[{"awards": "1917009 Thomson, Stuart; 1916982 Teyssier, Christian; 1917176 Siddoway, Christine", "bounds_geometry": "POLYGON((-160.16 -67.15,-154.572 -67.15,-148.984 -67.15,-143.39600000000002 -67.15,-137.808 -67.15,-132.22 -67.15,-126.632 -67.15,-121.04400000000001 -67.15,-115.456 -67.15,-109.868 -67.15,-104.28 -67.15,-104.28 -68.165,-104.28 -69.18,-104.28 -70.19500000000001,-104.28 -71.21000000000001,-104.28 -72.225,-104.28 -73.24,-104.28 -74.255,-104.28 -75.27,-104.28 -76.285,-104.28 -77.3,-109.868 -77.3,-115.456 -77.3,-121.044 -77.3,-126.632 -77.3,-132.22 -77.3,-137.808 -77.3,-143.396 -77.3,-148.98399999999998 -77.3,-154.572 -77.3,-160.16 -77.3,-160.16 -76.285,-160.16 -75.27,-160.16 -74.255,-160.16 -73.24,-160.16 -72.225,-160.16 -71.21000000000001,-160.16 -70.19500000000001,-160.16 -69.18,-160.16 -68.165,-160.16 -67.15))", "dataset_titles": "Apatite fission track thermochronology data for detrital minerals, offshore clasts, and bedrock; U-Pb detrital zircon geochronological data, obtained by LA-ICP-MS", "datasets": [{"dataset_uid": "200333", "doi": "", "keywords": null, "people": null, "repository": "in progress", "science_program": null, "title": "Apatite fission track thermochronology data for detrital minerals, offshore clasts, and bedrock", "url": ""}, {"dataset_uid": "200332", "doi": "", "keywords": null, "people": null, "repository": "in progress", "science_program": null, "title": "U-Pb detrital zircon geochronological data, obtained by LA-ICP-MS", "url": ""}], "date_created": "Wed, 19 Oct 2022 00:00:00 GMT", "description": "Sediment records off the coast of Marie Byrd Land (MBL), Antarctica suggest frequent and dramatic changes in the size of the West Antarctic Ice Sheet (WAIS) over short (tens of thousands of years) and long (millions of years) time frames in the past. WAIS currently overrides much of MBL and covers the rugged and scoured bedrock landscape. The ice sheet carved narrow linear troughs that reach depths of two to three thousand meters below sea level as outlet glaciers flowed from the interior of the continent to the oceans. As a result, large volumes of fragmented continental bedrock were carried out to the seabed. The glaciers cut downward into a region of crystalline rocks (i.e. granite) whose temperature change as a function of rock depth happens to be significant. This strong geothermal gradient in the bedrock is favorable for determining when the bedrock experienced rapid exhumation or \"uncovering\". Analyzing the chemistry of minerals (zircon and apatite) within the eroded rocks will provide information about the rate and timing of the glacier removal of bedrock from the Antarctic continent. The research addresses the following questions: When did the land become high enough for a large ice sheet to form? What was the regional pre-glacial topography? Under what climate conditions, and at what point in the growth of an ice sheet, did glaciers begin to cut sharply into bedrock to form the narrow troughs that flow seaward? The research will lead to greater understanding of past Antarctic ice sheet fluctuations and identify precise timing of glacial incision. These results will refine ice sheet history and aid the international societal response to contemporary ice sheet change and its global consequences. The project will contribute to the training of two graduate and two undergraduate students in STEM. The objective is to clarify the onset of WAIS glacier incision and assess the evolution of Cenozoic paleo-topography. Low-temperature (T) thermochronology and Pecube 3-D thermo-kinematic modeling will be applied to date and characterize episodes of glacial erosional incision. Single-grain double- and triple-dating of zircon and apatite will reveal the detailed crustal thermal evolution of the region enabling the research team to determine the comparative topographic influences on glaciation versus bedrock uplift induced by Eocene to present tectonism/magmatism. High-T mineral thermochronometers across Marie Byrd Land (MBL) record rapid extension-related cooling at ~100 Ma from temperatures of \u003e800 degrees C to \u0026#8804; 300 degrees C. This signature forms a reference horizon, or paleogeotherm, through which the Cenozoic landscape history using low-T thermochronometers can be explored. MBL\u0027s elevated geothermal gradient, sustained during the Cenozoic, created favorable conditions for sensitive apatite and zircon low-T thermochronometers to record bedrock cooling related to glacial incision. Students will be trained to use state-of-the-art analytical facilities in Arizona and Minnesota, expanding the geo- and thermochronologic history of MBL from bedrock samples and offshore sedimentary deposits. The temperature and time data they acquire will provide constraints on paleotopography, isostasy, and the thermal evolution of MBL that will be modeled in 3D using Pecube model simulations. Within hot crust, less incision is required to expose bedrock containing the distinct thermochronometric profile; a prediction that will be tested with inverse Pecube 3-D models of the thermal field through which bedrock and detrital samples cooled. Using results from Pecube, the ICI-Hot team will examine time-varying topography formed in response to changes in erosion rates, topographic relief, geothermal gradient and/or flexural isostatic rigidity. These effects are manifestations of dynamic processes in the WAIS, including ice sheet loading, ice volume fluctuations, relative motion upon crustal faults, and magmatism-related elevation increase across the MBL dome. The project makes use of pre-existing sample collections housed at the US Polar Rock Repository, IODP\u0027s Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -104.28, "geometry": "POINT(-132.22 -72.225)", "instruments": null, "is_usap_dc": true, "keywords": "Marie Byrd Land; GLACIERS/ICE SHEETS; Zircon; Subglacial Topography; FIELD SURVEYS; TECTONICS; Ice Sheet; Thermochronology; Apatite; ROCKS/MINERALS/CRYSTALS; Erosion; United States Of America; LABORATORY", "locations": "United States Of America; Marie Byrd Land", "north": -67.15, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": "PHANEROZOIC", "persons": "Siddoway, Christine; Thomson, Stuart; Teyssier, Christian", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "in progress", "repositories": "in progress", "science_programs": null, "south": -77.3, "title": "Collaborative Research: Ice sheet erosional interaction with hot geotherm in West Antarctica", "uid": "p0010386", "west": -160.16}, {"awards": "1543533 Johnson, Jesse; 1543530 van der Veen, Cornelis", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": null, "datasets": null, "date_created": "Wed, 19 Oct 2022 00:00:00 GMT", "description": "Van der Veen/1543530 The objective of this research is to gain better understanding of the West Antarctic ice flow in the transition region from grounded ice to floating ice shelves and investigate the conditions that can initiate and sustain major retreat of these glaciers. Several major Antarctic outlet glaciers and ice streams will be investigated using a suite of observational techniques and modeling tools. Glaciers include Thwaites Glacier, which has become a focal point in the discussion of West Antarctic retreat, Whillans Ice Stream as an example of the archetype ice stream, and Byrd Glacier, a major outlet glacier draining East Antarctica through the Transantarctic Mountains into the Ross Ice Shelf. This study will investigate whether the ongoing changes in these glaciers will lead to long-term mass loss (the onset of ice sheet collapse), or whether these glaciers will quickly stabilize with a new geometry. To adequately incorporate the dynamic behavior of outlet glaciers and ice streams requires inclusion of the relevant physical processes, and the development of regional models that employ a numerical grid with a horizontal grid spacing sufficiently refined to capture smaller-scale bed topographic features that may control the flow of these glaciers. This award revisits the issue of stability of marine-terminating glaciers whose grounding line is located on a retrograded bed slope. In particular, an attempt will be made to resolve the question whether observed rapid changes are the result of perturbations at the terminus or grounding line, or whether these changes reflect ice-dynamical forcing over the grounded reaches. High-resolution satellite imagery will be used to investigate ice-flow perturbations on smaller spatial scales than has been done before, to evaluate the importance of localized sites of high basal resistance on grounding-line stability. This collaborative project involves a range of modeling strategies including force-budget analysis, flow-band modeling, Full Stokes modeling for local studies, and using the Ice Sheet System Model developed at JPL for regional modeling. Broader Impacts include training two graduate students in computer simulations and ice sheet modeling algorithms. The work will also expand on a web-based interactive flowline model, so that it includes more realistic grounding line dynamics.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "Ice Sheet Dynamics; MODELS; Iceberg Calving; GLACIERS/ICE SHEETS; Numerical Glacier Modeling; Basal Sliding; Antarctica", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "van der Veen, Cornelis; Stearns, Leigh; Paden, John", "platforms": "OTHER \u003e MODELS", "repositories": null, "science_programs": null, "south": -90.0, "title": "Collaborative Research: Stability and Dynamics of Antarctic Marine Outlet Glaciers", "uid": "p0010387", "west": -180.0}, {"awards": "2218402 Fegyveresi, John", "bounds_geometry": "POLYGON((-115 -85.5,-113.5 -85.5,-112 -85.5,-110.5 -85.5,-109 -85.5,-107.5 -85.5,-106 -85.5,-104.5 -85.5,-103 -85.5,-101.5 -85.5,-100 -85.5,-100 -85.65,-100 -85.8,-100 -85.95,-100 -86.1,-100 -86.25,-100 -86.4,-100 -86.55,-100 -86.7,-100 -86.85,-100 -87,-101.5 -87,-103 -87,-104.5 -87,-106 -87,-107.5 -87,-109 -87,-110.5 -87,-112 -87,-113.5 -87,-115 -87,-115 -86.85,-115 -86.7,-115 -86.55,-115 -86.4,-115 -86.25,-115 -86.1,-115 -85.95,-115 -85.8,-115 -85.65,-115 -85.5))", "dataset_titles": "Multi-Site Brittle Ice Data and Measurements", "datasets": [{"dataset_uid": "601786", "doi": "10.15784/601786", "keywords": "Antarctica; Brittle Ice; Cryosphere; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Glaciology; Ice Core; Ice Core Records; Ice Core Records; Physical Properties; Simple Dome; Siple Dome; South Pole; SPICEcore; Subgrain Boundaries; WAIS Divide", "people": "Barnett, Samantha; Fegyveresi, John", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Multi-Site Brittle Ice Data and Measurements", "url": "https://www.usap-dc.org/view/dataset/601786"}], "date_created": "Mon, 19 Sep 2022 00:00:00 GMT", "description": "Ice cores are a vital source of information about past climate. Research that utilizes ice cores benefits from an undamaged ice-core record. There is often a zone within ice sheets where the ice is brittle upon extraction in a core. Brittle-ice behavior occurs when the rapid decompression of the core as it is being extracted from the ice-sheet results in extensive fracturing. Ice from this zone can compromise the undamaged record. This project seeks to improve our understanding of the mechanisms involved in brittle-ice behavior and onset, with the goal of helping to guide field-site operations, core handling preparation, and planned laboratory measurement techniques for future ice-coring projects, including the upcoming work at Hercules Dome. This project requires no field work, as it will use existing observations and existing ice cores to gain an understanding of brittle ice. This is a high-risk and timely proposal that is early-concept and exploratory in nature, making it appropriate for the EAGER solicitation. The project will support an early-career researcher and provide training for a master\u2019s student who is a woman. And, finally, the project will develop educational and outreach materials for graduate and undergraduate courses and elementary schools. This project will examine and catalog brittle ice from several existing ice-core samples to specifically assess various ice physical properties affecting brittleness potential, including bubble size and number-density, ice fabric, grain statistics, fracture characteristics, and the location and properties of grain and subgrain boundaries. End members of this sample assessment have been identified and include Siple Dome, which exhibited major brittle behavior and damage, and South Pole ice core, which exhibited very-minor brittle behavior and almost no damage. Output datasets will include calibrated relationships for bubble number-density, mean grain and bubble sizes, subgrain prevalence and orientation, and a usable indicator for estimating brittle-ice onset and magnitude. There is an immediate applicability of results from this effort for the Hercules Dome drilling project. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -100.0, "geometry": "POINT(-107.5 -86.25)", "instruments": null, "is_usap_dc": true, "keywords": "Hercules Dome Ice Core; West Antarctica; Grain Statistics; LABORATORY; Ice Core; ICE SHEETS; Physical Properties; Brittle Ice; C-Axis Fabric; Bubble; ICE CORE RECORDS", "locations": "West Antarctica", "north": -85.5, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fegyveresi, John", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Hercules Dome Ice Core", "south": -87.0, "title": "EAGER: Constraining the Expected Brittle-ice Behavior for the Hercules Dome Ice-core Site.", "uid": "p0010378", "west": -115.0}, {"awards": "2114502 Tinto, Kirsteen", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": null, "datasets": null, "date_created": "Tue, 19 Jul 2022 00:00:00 GMT", "description": "This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). An important part of understanding future climate change is predicting changes in how fast the ice in Antarctica is moving. If ice flows more quickly towards the ocean, it will have a direct impact on sea level rise. One of the things that can influence the ice flow is the type of rock below the ice coverage in Antarctica. Sedimentary basins are large regions where sedimentary rocks accumulated in the past, often under ancient seas. It has been observed that where there are sediments below the ice, the ice can flow faster. This project seeks to understand what is below the ice and how the underlying rock influences the ice flow. Is it hard, crystalline rock? Is it a sedimentary basin? What is the relationship between sediments and ice flow? The answers to these questions will be addressed by using a combination of available data and geophysical methods. Information from well-known rock-types will be used to train the computer to recognize these features by using an application of artificial intelligence known as machine learning, which will help the characterization and identification of unknown sedimentary basins beneath the ice. The results of this project will be disseminated to a broad audience by holding workshops for teacher and students to explain our findings under the ice and to introduce the machine learning technique. Open-source codes used during this project will be made available for use in higher-level classrooms as well as in further studies. To date, no comprehensive distribution of onshore and offshore sedimentary basins over Antarctica has been developed. A combination of large-scale datasets will be used to characterize known basins and identify new sedimentary basins to produce the first continent-wide mapping of sedimentary basins and provide improved basal parametrizations conditions that have the potential to support more realistic ice sheet models. Available geophysical compilations of data and the location of well-known sedimentary basins will be used to apply an ensemble machine learning algorithm. The machine learning algorithm will learn complex relationships by voting among a collection of randomized decision trees. The gravity signal related to sedimentary basins known from other (e.g. seismic) techniques will be evaluated and unknown basins from aerogravity data regression analyses will be proposed by calculating a gravity residual that reflects density inhomogeneities. The gravimetric sedimentary basins identified from the regression analyses will be compared with an independent method of identifying sedimentary distribution, the Werner deconvolution method of estimating depth to magnetic sources. The hypothesis, which is sedimentary basins are correlated to fast ice flow behavior, will be tested by comparing the location of the sedimentary basins with locations of high ice flow by using available ice velocity observations. A relationship between sedimentary basins and ice streams will be defined qualitatively and quantitatively, aiming to evaluate if there are ice streams where no sedimentary basins are reported, or sedimentary basins with no ice streams related. The findings of these project can confirm if the presence of abundant sediments is a pre-requisite for ice streaming. Analyzing previously known sedimentary basins and identifying new ones in Antarctica is central to evaluating the influence of subglacial sediments on the ice sheet flow. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "GRAVITY ANOMALIES; ICE SHEETS; Antarctica", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Constantino, Renata", "platforms": null, "repositories": null, "science_programs": null, "south": -90.0, "title": "Pan-Antarctic Assessment of Sedimentary Basins and the Onset of Streaming Ice Flow from Machine Learning and Aerogravity Regression Analyses", "uid": "p0010351", "west": -180.0}, {"awards": "2114839 Passchier, Sandra", "bounds_geometry": null, "dataset_titles": "Argon thermochronological data on Pliocene ice-rafted detrital mineral grains from IODP Expedition 379 in the Amundsen Sea sector; Grain-size data for the Pliocene section at IODP Site U1533, Amundsen Sea", "datasets": [{"dataset_uid": "601900", "doi": "10.15784/601900", "keywords": "Amundsen Sea Sector; Antarctica; Cryosphere; Glaciation; Grain Size; Pliocene; Sediment Core Data; Sedimentology", "people": "Mino-Moreira, Lisbeth; Passchier, Sandra", "repository": "USAP-DC", "science_program": null, "title": "Grain-size data for the Pliocene section at IODP Site U1533, Amundsen Sea", "url": "https://www.usap-dc.org/view/dataset/601900"}, {"dataset_uid": "601907", "doi": "10.15784/601907", "keywords": "40Ar/39Ar; Amundsen Sea; Amundsen Sea Sector; Antarctica; Cryosphere; Ice-Rafted Detritus; IODP; Paleoclimate; Pliocene; Provenance; Sedimentology", "people": "Hemming, Sidney R.; Passchier, Sandra", "repository": "USAP-DC", "science_program": null, "title": "Argon thermochronological data on Pliocene ice-rafted detrital mineral grains from IODP Expedition 379 in the Amundsen Sea sector", "url": "https://www.usap-dc.org/view/dataset/601907"}], "date_created": "Wed, 25 Aug 2021 00:00:00 GMT", "description": "The West Antarctic Ice Sheet is the most vulnerable polar ice mass to warming and already a major contributor to global mean sea level rise. Its fate in the light of prolonged warming is a topic of major uncertainty. Accelerated sea level rise from ice mass loss in the polar regions is a major concern as a cause of increased coastal flooding affecting millions of people. This project will disclose a unique geological archive buried beneath the seafloor off the Amundsen Sea, Antarctica, which will reveal how the West Antarctic Ice Sheet behaved in a warmer climate in the past. The data and insights can be used to inform ice-sheet and ocean modeling used in coastal policy development. The project will also support the development of a competitive U.S. STEM workforce. Online class exercises for introductory geology classes will provide a gateway for qualified students into undergraduate research programs and this project will enhance the participation of women in science by funding the education of current female Ph.D. students. The project targets the long-term variability of the West Antarctic Ice Sheet over several glacial-interglacial cycles in the early Pliocene sedimentary record drilled by the International Ocean Discovery Program (IODP) Expedition 379 in the Amundsen Sea. Data collection includes 1) the sand provenance of ice-rafted debris and shelf diamictites and its sources within the Amundsen Sea and Antarctic Peninsula region; 2) sedimentary structures and sortable silt calculations from particle size records and reconstructions of current intensities and interactions; and 3) the bulk provenance of continental rise sediments compared to existing data from the Amundsen Sea shelf with investigations into downslope currents as pathways for Antarctic Bottom Water formation. The results are analyzed within a cyclostratigraphic framework of reflectance spectroscopy and colorimetry (RSC) and X-ray fluorescence scanner (XRF) data to gain insight into orbital forcing of the high-latitude processes. The early Pliocene Climatic Optimum (PCO) ~4.5-4.1 Ma spans a major warm period recognized in deep-sea stable isotope and sea-surface temperature records. This period also coincides with a global mean sea level highstand of \u003e 20 m requiring contributions in ice mass loss from Antarctica. The following hypotheses will be tested: 1) that the West Antarctic Ice Sheet retreated from the continental shelf break through an increase in sub iceshelf melt and iceberg calving at the onset of the PCO ~4.5 Ma, and 2) that dense shelf water cascaded down through slope channels after ~4.5 Ma as the continental shelf became exposed during glacial terminations. The project will reveal for the first time how the West Antarctic Ice Sheet operated in a warmer climate state prior to the onset of the current \u201cicehouse\u201d period ~3.3 Ma. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "USA/NSF; TERRIGENOUS SEDIMENTS; Amd/Us; SEDIMENTS; FIELD SURVEYS; Amundsen Sea; USAP-DC; AMD", "locations": "Amundsen Sea", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Passchier, Sandra", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "West Antarctic Ice-sheet Change and Paleoceanography in the Amundsen Sea Across the Pliocene Climatic Optimum", "uid": "p0010252", "west": null}, {"awards": "1443556 Thomson, Stuart; 1443342 Licht, Kathy", "bounds_geometry": null, "dataset_titles": "Apatite (U-Th)/He and TREE Data Central Transantarctic Mountains", "datasets": [{"dataset_uid": "601462", "doi": "10.15784/601462", "keywords": "Antarctica; Beardmore Glacier; Erosion; Landscape Evolution; Shackleton Glacier; Transantarctic Mountains; (U-Th)/He", "people": "He, John; Hemming, Sidney R.; Licht, Kathy; Reiners, Peter; Thomson, Stuart", "repository": "USAP-DC", "science_program": null, "title": "Apatite (U-Th)/He and TREE Data Central Transantarctic Mountains", "url": "https://www.usap-dc.org/view/dataset/601462"}], "date_created": "Wed, 09 Jun 2021 00:00:00 GMT", "description": "Antarctica is almost entirely covered by ice, in places over two miles thick. This ice hides a landscape that is less well known than the surface of Mars and represents one of Earth\u0027s last unexplored frontiers. Ice-penetrating radar images provide a remote glimpse of this landscape including ice-buried mountains larger than the European Alps and huge fjords twice as deep as the Grand Canyon. The goal of this project is to collect sediment samples derived from these landscapes to determine when and under what conditions these features formed. Specifically, the project seeks to understand the landscape in the context of the history and dynamics of the overlying ice sheet and past mountain-building episodes. This project accomplishes this goal by analyzing sand collected during previous sea-floor drilling expeditions off the coast of Antarctica. This sand was supplied from the continent interior by ancient rivers when it was ice-free over 34 million year ago, and later by glaciers. The project will also study bedrock samples from rare ice-free parts of the Transantarctic Mountains. The primary activity is to apply multiple advanced dating techniques to single mineral grains contained within this sand and rock. Different methods and minerals yield different dates that provide insight into how Antarctica?s landscape has eroded over the many tens of millions of years during which sand was deposited offshore. The dating techniques that are being developed and enhanced for this study have broad application in many branches of geoscience research and industry. The project makes cost-effective use of pre-existing sample collections housed at NSF facilities including the US Polar Rock Repository, the Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. The project will contribute to the STEM training of two graduate and two undergraduate students, and includes collaboration among four US universities as well as international collaboration between the US and France. The project also supports outreach in the form of a two-week open workshop giving ten students the opportunity to visit the University of Arizona to conduct STEM-based analytical work and training on Antarctic-based projects. Results from both the project and workshop will be disseminated through presentations at professional meetings, peer-reviewed publications, and through public outreach and media. The main objective of this project is to reconstruct a chronology of East Antarctic subglacial landscape evolution to understand the tectonic and climatic forcing behind landscape modification, and how it has influenced past ice sheet inception and dynamics. Our approach focuses on acquiring a record of the cooling and erosion history contained in East Antarctic-derived detrital mineral grains and clasts in offshore sediments deposited both before and after the onset of Antarctic glaciation. Samples will be taken from existing drill core and marine sediment core material from offshore Wilkes Land (100\u00b0E-160\u00b0E) and the Ross Sea. Multiple geo- and thermo-chronometers will be employed to reconstruct source region cooling history including U-Pb, fission-track, and (U-Th)/He dating of zircon and apatite, and 40Ar/39Ar dating of hornblende, mica, and feldspar. This offshore record will be augmented and tested by applying the same methods to onshore bedrock samples in the Transantarctic Mountains obtained from the US Polar Rock Repository and through fieldwork. The onshore work will additionally address the debated incision history of the large glacial troughs that cut the range, now occupied by glaciers draining the East Antarctic Ice Sheet. This includes collection of samples from several age-elevation transects, apatite 4He/3He thermochronometry, and Pecube thermo-kinematic modeling. Acquiring an extensive geo- and thermo-chronologic database will also provide valuable new information on the poorly known ice-hidden geology and tectonics of subglacial East Antarctica that has implications for improving supercontinent reconstructions and understanding continental break-up.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "LABORATORY; LANDSCAPE; AGE DETERMINATIONS; FIELD INVESTIGATION; GLACIAL PROCESSES; Transantarctic Mountains; USA/NSF; Thermochronology; Amd/Us; USAP-DC; TRACE ELEMENTS; Provenance Analysis; AMD; LANDFORMS; GLACIAL LANDFORMS", "locations": "Transantarctic Mountains", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Thomson, Stuart; Reiners, Peter; Licht, Kathy", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: East Antarctic Glacial Landscape Evolution (EAGLE): A Study using Combined Thermochronology, Geochronology and Provenance Analysis", "uid": "p0010188", "west": null}, {"awards": "1753101 Bernard, Kim", "bounds_geometry": "POLYGON((-65 -64,-64.7 -64,-64.4 -64,-64.1 -64,-63.8 -64,-63.5 -64,-63.2 -64,-62.9 -64,-62.6 -64,-62.3 -64,-62 -64,-62 -64.1,-62 -64.2,-62 -64.3,-62 -64.4,-62 -64.5,-62 -64.6,-62 -64.7,-62 -64.8,-62 -64.9,-62 -65,-62.3 -65,-62.6 -65,-62.9 -65,-63.2 -65,-63.5 -65,-63.8 -65,-64.1 -65,-64.4 -65,-64.7 -65,-65 -65,-65 -64.9,-65 -64.8,-65 -64.7,-65 -64.6,-65 -64.5,-65 -64.4,-65 -64.3,-65 -64.2,-65 -64.1,-65 -64))", "dataset_titles": "2019 Krill Carbon Content; 2019 Krill Morphometrics; CAREER: \"The Omnivores Dilemma\": The Effect of Autumn Diet on Winter Physiology and Condition of Juvenile Antarctic Krill; Expedition of NBP2205; Feeding Experiment - Krill Lipid Classes; Gerlache Strait Krill Demographics", "datasets": [{"dataset_uid": "601708", "doi": "10.15784/601708", "keywords": "Antarctica; Antarctic Krill; Palmer Station; Winter", "people": "Bernard, Kim", "repository": "USAP-DC", "science_program": null, "title": "2019 Krill Morphometrics", "url": "https://www.usap-dc.org/view/dataset/601708"}, {"dataset_uid": "601707", "doi": "10.15784/601707", "keywords": "Antarctica; Antarctic Krill; Palmer Station; Winter", "people": "Bernard, Kim", "repository": "USAP-DC", "science_program": null, "title": "Feeding Experiment - Krill Lipid Classes", "url": "https://www.usap-dc.org/view/dataset/601707"}, {"dataset_uid": "601706", "doi": "10.15784/601706", "keywords": "Abundance; Antarctica; Antarctic Krill", "people": "Bernard, Kim", "repository": "USAP-DC", "science_program": null, "title": "Gerlache Strait Krill Demographics", "url": "https://www.usap-dc.org/view/dataset/601706"}, {"dataset_uid": "200368", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "CAREER: \"The Omnivores Dilemma\": The Effect of Autumn Diet on Winter Physiology and Condition of Juvenile Antarctic Krill", "url": "https://www.bco-dmo.org/project/824760"}, {"dataset_uid": "601709", "doi": "10.15784/601709", "keywords": "Antarctica; Antarctic Krill; Palmer Station; Winter", "people": "Bernard, Kim", "repository": "USAP-DC", "science_program": null, "title": "2019 Krill Carbon Content", "url": "https://www.usap-dc.org/view/dataset/601709"}, {"dataset_uid": "200369", "doi": "10.7284/909918", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition of NBP2205", "url": "https://www.rvdata.us/search/cruise/NBP2205"}], "date_created": "Mon, 31 Aug 2020 00:00:00 GMT", "description": "Antarctic krill are essential in the Southern Ocean as they support vast numbers of marine mammals, seabirds and fishes, some of which feed almost exclusively on krill. Antarctic krill also constitute a target species for industrial fisheries in the Southern Ocean. The success of Antarctic krill populations is largely determined by the ability of their young to survive the long, dark winter, where food is extremely scarce. To survive the long-dark winter, young Antarctic krill must have a high-quality diet in autumn. However, warming in certain parts of Antarctica is changing the dynamics and quality of the polar food web, resulting in a shift in the type of food available to young krill in autumn. It is not yet clear how these dynamic changes are affecting the ability of krill to survive the winter. This project aims to fill an important gap in current knowledge on an understudied stage of the Antarctic krill life cycle, the 1-year old juveniles. The results derived from this work will contribute to the development of improved bioenergetic, population and ecosystem models, and will advance current scientific understanding of this critical Antarctic species. This CAREER project\u0027s core education and outreach objectives seek to enhance education and increase diversity within STEM fields. An undergraduate course will be developed that will integrate undergraduate research and writing in way that promotes authentic scientific inquiry and analysis of original research data by the students, and that enhances their communication skills. A graduate course will be developed that will promote students\u0027 skills in communicating their own research to a non-scientific audience. Graduate students will be supported through the proposed study and will gain valuable research experience. Traditionally underserved undergraduate students will be recruited to conduct independent research under the umbrella of the larger project. Throughout each field season, the research team will maintain a weekly blog that will include short videos, photographs and text highlighting the research, as well as their experiences living and working in Antarctica. The aim of the blog will be to engage the public and increase awareness and understanding of Antarctic ecosystems and the impact of warming, and of the scientific process of research and discovery. In this 5-year CAREER project, the investigator will use a combination of empirical and theoretical techniques to assess the effects of diet on 1-year old krill in autumn-winter. The research is centered on four hypotheses: (H1) autumn diet affects 1-year old krill physiology and condition at the onset of winter; (H2) autumn diet has an effect on winter physiology and condition of 1-year old krill under variable winter food conditions; (H3) the rate of change in physiology and condition of 1-year old krill from autumn to winter is dependent on autumn diet; and (H4) the winter energy budget of 1-year old krill will vary between years and will be dependent on autumn diet. Long-term feeding experiments and in situ sampling will be used to measure changes in the physiology and condition of krill in relation to their diet and feeding environment. Empirically-derived data will be used to develop theoretical models of growth rates and energy budgets to determine how diet will influence the overwinter survival of 1-year old krill. The research will be integrated with an education and outreach plan to (1) develop engaging undergraduate and graduate courses, (2) train and develop young scientists for careers in polar research, and (3) engage the public and increase their awareness and understanding. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -62.0, "geometry": "POINT(-63.5 -64.5)", "instruments": null, "is_usap_dc": true, "keywords": "Antarctic Peninsula; AMD; FIELD INVESTIGATION; ANIMALS/INVERTEBRATES; PELAGIC; Anvers Island; Amd/Us; USAP-DC; NSF/USA", "locations": "Antarctic Peninsula; Anvers Island", "north": -64.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Bernard, Kim", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "BCO-DMO; R2R; USAP-DC", "science_programs": null, "south": -65.0, "title": "CAREER: \"The Omnivore\u0027s Dilemma\": The Effect of Autumn Diet on Winter Physiology and Condition of Juvenile Antarctic Krill", "uid": "p0010124", "west": -65.0}, {"awards": "1543483 Sedwick, Peter", "bounds_geometry": "POLYGON((-180 -66,-179.5 -66,-179 -66,-178.5 -66,-178 -66,-177.5 -66,-177 -66,-176.5 -66,-176 -66,-175.5 -66,-175 -66,-175 -67.2,-175 -68.4,-175 -69.6,-175 -70.8,-175 -72,-175 -73.2,-175 -74.4,-175 -75.6,-175 -76.8,-175 -78,-175.5 -78,-176 -78,-176.5 -78,-177 -78,-177.5 -78,-178 -78,-178.5 -78,-179 -78,-179.5 -78,180 -78,178.5 -78,177 -78,175.5 -78,174 -78,172.5 -78,171 -78,169.5 -78,168 -78,166.5 -78,165 -78,165 -76.8,165 -75.6,165 -74.4,165 -73.2,165 -72,165 -70.8,165 -69.6,165 -68.4,165 -67.2,165 -66,166.5 -66,168 -66,169.5 -66,171 -66,172.5 -66,174 -66,175.5 -66,177 -66,178.5 -66,-180 -66))", "dataset_titles": "Impact of Convective Processes and Sea Ice Formation on the Distribution of Iron in the Ross Sea: Closing the Seasonal Cycle; NBP1704 Expedition Data", "datasets": [{"dataset_uid": "200150", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Impact of Convective Processes and Sea Ice Formation on the Distribution of Iron in the Ross Sea: Closing the Seasonal Cycle", "url": "https://www.bco-dmo.org/project/815403"}, {"dataset_uid": "001363", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "NBP1704 Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP1704"}], "date_created": "Mon, 22 Jun 2020 00:00:00 GMT", "description": "The waters of the Ross Sea continental shelf are among the most productive in the Southern Ocean, and may comprise a significant regional oceanic sink for atmospheric carbon dioxide. In this region, primary production can be limited by the supply of dissolved iron to surface waters during the growing season. Water-column observations, sampling and measurements are to be carried out in the late autumn-early winter time frame on the Ross Sea continental shelf and coastal polynyas (Terra Nova Bay and Ross Ice Shelf polynyas), in order to better understand what drives the biogeochemical redistribution of micronutrient iron species during the onset of convective mixing and sea-ice formation at this time of year, thereby setting conditions for primary production during the following spring. The spectacular field setting and remote, hostile conditions that accompany the proposed field study present exciting possibilities for STEM education and training. At the K-12 level, the project seeks to support the development of educational outreach materials targeting elementary and middle school students, pre-service science teachers, and in-service science teachers.", "east": 165.0, "geometry": "POINT(175 -72)", "instruments": null, "is_usap_dc": true, "keywords": "POLYNYAS; USAP-DC; NBP1704; Iron; Ross Sea; TRACE ELEMENTS; SALINITY/DENSITY; R/V NBP; MARINE ECOSYSTEMS; BIOGEOCHEMICAL CYCLES", "locations": "Ross Sea", "north": -66.0, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Sedwick, Peter", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "BCO-DMO", "repositories": "BCO-DMO; R2R", "science_programs": null, "south": -78.0, "title": "Impact of Convective Processes and Sea Ice Formation on the Distribution of Iron in the Ross Sea: Closing the Seasonal Cycle", "uid": "p0010111", "west": -175.0}, {"awards": "1743643 Passchier, Sandra", "bounds_geometry": null, "dataset_titles": "Major and trace element analyses of Eocene-Oligocene marine sediments from ODP Site 696, South Orkney Microcontinent; Particle-size distributions of Eocene-Oligocene sediment from ODP Site 696, South Orkney Microcontinent", "datasets": [{"dataset_uid": "601582", "doi": "10.15784/601582", "keywords": "Antarctica; Glaciation; IODP 650; IODP 696; Paleoceanography; Provenance; Sediment Core Data; Weathering; Weddell Sea", "people": "Passchier, Sandra; Lepp, Allison; States, Abbey; Li, Xiaona; Hojnacki, Victoria", "repository": "USAP-DC", "science_program": null, "title": "Major and trace element analyses of Eocene-Oligocene marine sediments from ODP Site 696, South Orkney Microcontinent", "url": "https://www.usap-dc.org/view/dataset/601582"}, {"dataset_uid": "601581", "doi": "10.15784/601581", "keywords": "Antarctica; Glaciation; IODP 696; Marine Geoscience; Marine Sediments; Paleoceanography; Sediment Core Data; Weddell Sea", "people": "Horowitz Castaldo, Josie; Passchier, Sandra; Lepp, Allison; Light, Jennifer", "repository": "USAP-DC", "science_program": null, "title": "Particle-size distributions of Eocene-Oligocene sediment from ODP Site 696, South Orkney Microcontinent", "url": "https://www.usap-dc.org/view/dataset/601581"}], "date_created": "Tue, 26 May 2020 00:00:00 GMT", "description": "Abstract (non-technical) Sea level rise is a problem of global importance and it is increasingly affecting the tens of millions of Americans living along coastlines. The melting of glaciers in mountain areas worldwide in response to global warming is a major cause of sea level rise and increases in nuisance coastal flooding. However, the world\u0027s largest land-based ice sheets are situated in the Polar Regions and their response under continued warming is very difficult to predict. One reason for this uncertainty is a lack of observations of ice behavior and melt under conditions of warming, as it is a relatively new global climate state lasting only a few generations so far. Researchers will investigate ice growth on Antarctica under past warm conditions using geological archives embedded in the layers of sand and mud under the sea floor near Antarctica. By peeling back at the layers beneath the seafloor investigators can read the history book of past events affecting the ice sheet. The Antarctic continent on the South Pole, carries the largest ice mass in the world. The investigator\u0027s findings will substantially improve scientists understanding of the response of ice sheets to global warming and its effect on sea level rise. Abstract (technical) The melt of land based ice is raising global sea levels with at present only minor contributions from polar ice sheets. However, the future role of polar ice sheets in climate change is one of the most critical uncertainties in predictions of sea level rise around the globe. The respective roles of oceanic and atmospheric greenhouse forcing on ice sheets are poorly addressed with recent measurements of polar climatology, because of the extreme rise in greenhouse forcing the earth is experiencing at this time. Data on the evolution of the West Antarctic ice sheet is particularly sparse. To address the data gap, researchers will reconstruct the timing and spatial distribution of Antarctic ice growth through the last greenhouse to icehouse climate transition around 37 to 33 Ma. They will collect sedimentological and geochemical data on core samples from a high-latitude paleoarchive to trace the shutdown of the chemical weathering system, the onset of glacial erosion, ice rafting, and sea ice development, as East and West Antarctic ice sheets coalesced in the Weddell Sea sector. Their findings will lead to profound increases in the understanding of the role of greenhouse forcing in ice sheet development and its effect on the global climate system. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "Amd/Us; AMD; SEDIMENTS; LABORATORY; USA/NSF; USAP-DC; Weddell Sea", "locations": "Weddell Sea", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Passchier, Sandra", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Timing and Spatial Distribution of Antarctic Ice Sheet Growth and Sea-ice Formation across the Eocene-Oligocene Transition", "uid": "p0010101", "west": null}, {"awards": "1807522 Jones, Tyler", "bounds_geometry": "POINT(-112.085 -79.467)", "dataset_titles": "Mid-Holocene high-resolution water isotope time series for the WAIS Divide ice core; Seasonal temperatures in West Antarctica during the Holocene ; Stable Isotopes of Ice in the Transition and Glacial Sections of the WAIS Divide Deep Ice Core", "datasets": [{"dataset_uid": "601326", "doi": "10.15784/601326", "keywords": "Antarctica; Delta 18O; Delta Deuterium; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Snow/ice; Snow/Ice; WAIS Divide Ice Core; Water Isotopes; West Antarctic Ice Sheet", "people": "Morris, Valerie; Jones, Tyler R.; Vaughn, Bruce; White, James", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Mid-Holocene high-resolution water isotope time series for the WAIS Divide ice core", "url": "https://www.usap-dc.org/view/dataset/601326"}, {"dataset_uid": "601603", "doi": "10.15784/601603", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Seasonality; Seasonal Temperatures; Temperature; Water Isotopes; West Antarctic Ice Sheet", "people": "Jones, Tyler R.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Seasonal temperatures in West Antarctica during the Holocene ", "url": "https://www.usap-dc.org/view/dataset/601603"}, {"dataset_uid": "601274", "doi": "10.15784/601274", "keywords": "Antarctica; Delta 18O; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Isotope; Snow/ice; Snow/Ice; WAIS Divide; WAIS Divide Ice Core; West Antarctic Ice Sheet", "people": "Jones, Tyler R.; Vaughn, Bruce; White, James; Price, Michael; Garland, Joshua; Bradley, Elizabeth; Morris, Valerie", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Stable Isotopes of Ice in the Transition and Glacial Sections of the WAIS Divide Deep Ice Core", "url": "https://www.usap-dc.org/view/dataset/601274"}], "date_created": "Tue, 26 May 2020 00:00:00 GMT", "description": "Ice cores contain detailed accounts of Earth\u0027s climate history. The collection of an ice core can be logistically challenging, and extraction of data from the core can be time-consuming as well as susceptible to both human and machine error. Furthermore, locked in measurements from ice cores is information that scientists have not yet found ways to recover. This project will apply techniques from information theory to ice-core data to unlock that information. The primary goal is to demonstrate that information theory can (a) identify regions of a specific ice-core record that are in need of further analysis and (b) provide some specific guidance for that analysis. A secondary goal is to demonstrate that information theory has practical and scientific utility for studies of past climate. This project aims to use information theory in two distinct ways: first, to identify regions of a core where information appears to be damaged or missing, perhaps due to human and/or machine error. In the segment of the West Antarctic Ice Sheet Divide core that is 5000-8000 years old, for instance, information-theoretic methods reveal significant levels of noise, probably due to a laboratory instrument, and something that was not visible in the raw data. This is a particularly important segment of the record, as it contains valuable clues about climatic shifts and the onset of the Holocene. Targeted re-sampling of this segment of the core and reanalysis with newer laboratory apparatus could resolve the data issues. The second way in which information theory can potentially aid in ice-core analysis is by extracting climate signals from the data--such as the accumulation rate at the core site over the period of its formation. This quantity usually requires significant time and effort to produce, but information theory could help to streamline that process. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -112.085, "geometry": "POINT(-112.085 -79.467)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS", "is_usap_dc": true, "keywords": "AMD; West Antarctic Ice Sheet; ISOTOPES; Amd/Us; USAP-DC; USA/NSF; Water Isotopes; WAIS Divide Ice Core; Deuterium; LABORATORY", "locations": "West Antarctic Ice Sheet", "north": -79.467, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Garland, Joshua; Jones, Tyler R.", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.467, "title": "Collaborative Research: Targeted resampling of deep polar ice cores using information theory", "uid": "p0010100", "west": -112.085}, {"awards": "9319854 Bell, Robin; 9319877 Finn, Carol; 9319369 Blankenship, Donald", "bounds_geometry": "POLYGON((-155 -77.5,-150 -77.5,-145 -77.5,-140 -77.5,-135 -77.5,-130 -77.5,-125 -77.5,-120 -77.5,-115 -77.5,-110 -77.5,-105 -77.5,-105 -78.2,-105 -78.9,-105 -79.6,-105 -80.3,-105 -81,-105 -81.7,-105 -82.4,-105 -83.1,-105 -83.8,-105 -84.5,-110 -84.5,-115 -84.5,-120 -84.5,-125 -84.5,-130 -84.5,-135 -84.5,-140 -84.5,-145 -84.5,-150 -84.5,-155 -84.5,-155 -83.8,-155 -83.1,-155 -82.4,-155 -81.7,-155 -81,-155 -80.3,-155 -79.6,-155 -78.9,-155 -78.2,-155 -77.5))", "dataset_titles": "SOAR-BSB Airborne gravity data for the CASERTZ/WAIS project; SOAR-IRE airborne gravity data for the CASERTZ/WAIS project; SOAR-TKD airborne gravity data for the CASERTZ/WAIS project; SOAR-WAZ Airborne gravity data for the CASERTZ/WAIS project", "datasets": [{"dataset_uid": "601289", "doi": "10.15784/601289", "keywords": "Aerogeophysics; Airborne Gravity; Airplane; Antarctica; Free Air Gravity; Glaciers/ice Sheet; Glaciers/Ice Sheet; Gravimeter; Gravity; Gravity Data; Marie Byrd Land; Potential Field; Solid Earth; WAIS", "people": "Bell, Robin; Arko, Robert A.", "repository": "USAP-DC", "science_program": null, "title": "SOAR-TKD airborne gravity data for the CASERTZ/WAIS project", "url": "https://www.usap-dc.org/view/dataset/601289"}, {"dataset_uid": "601290", "doi": "10.15784/601290", "keywords": "Aerogeophysics; Airborne Gravity; Airplane; Antarctica; Free Air Gravity; Glaciers/ice Sheet; Glaciers/Ice Sheet; Gravimeter; Gravity; Gravity Data; Marie Byrd Land; Potential Field; Solid Earth; WAIS", "people": "Bell, Robin; Arko, Robert A.", "repository": "USAP-DC", "science_program": null, "title": "SOAR-IRE airborne gravity data for the CASERTZ/WAIS project", "url": "https://www.usap-dc.org/view/dataset/601290"}, {"dataset_uid": "601291", "doi": "10.15784/601291", "keywords": "Aerogeophysics; Airborne Gravity; Airplane; Antarctica; Free Air Gravity; Glaciers/ice Sheet; Glaciers/Ice Sheet; Gravimeter; Gravity; Gravity Data; Marie Byrd Land; Potential Field; Solid Earth; WAIS", "people": "Bell, Robin; Arko, Robert A.", "repository": "USAP-DC", "science_program": null, "title": "SOAR-WAZ Airborne gravity data for the CASERTZ/WAIS project", "url": "https://www.usap-dc.org/view/dataset/601291"}, {"dataset_uid": "601288", "doi": "10.15784/601288", "keywords": "Aerogeophysics; Airborne Gravity; Airplane; Antarctica; Free Air Gravity; Geology/Geophysics - Other; Glaciers/ice Sheet; Glaciers/Ice Sheet; Gravimeter; Gravity; Gravity Data; Marie Byrd Land; Solid Earth; WAIS", "people": "Arko, Robert A.; Bell, Robin", "repository": "USAP-DC", "science_program": null, "title": "SOAR-BSB Airborne gravity data for the CASERTZ/WAIS project", "url": "https://www.usap-dc.org/view/dataset/601288"}], "date_created": "Fri, 24 Apr 2020 00:00:00 GMT", "description": "Blankenship: 9319369 Bell: 9319854 Behrendt: 9319877 This award supports a project to conduct an integrated geophysical survey over a large portion of the West Antarctic Ice Sheet (WAIS) toward an understanding of the dynamic behavior of the ice sheet and the nature of the lithosphere beneath the ice sheet. West Antarctica is characterized by two kinds of the Earth s most dynamic systems, a continental rift (the West Antarctic Rift System) and a marine based ice sheet (the WAIS). Active continental rift systems, caused by divergent plate motions, result in thinned continental crust. Associated with the thin crust are fault-bounded sedimentary basins, active volcanism, and elevated heat flow. Marine ice sheets are characterized by rapidly moving streams of ice, penetrating and draining a slowly moving ice reservoir. Evidence left by past marine ice sheets indicates that they may have a strongly non- linear response to long-term climate change which results in massive and rapid discharges of ice. Understanding the evolution of the ice stream system and its interaction with the interior ice is the key to understanding this non-linear response. Subglacial geology and ice dynamics are generally studied in isolation, but evidence is mounting that the behavior of the West Antarctic ice streams may be closely linked to the nature of the underlying West Antarctic rift system. The fast moving ice streams appear to glide on a lubricating layer of water-saturated till. This till requires easily eroded sediment and a source of water, both of which may be controlled by the geology of the rift system; the sediments from the fault-bounded basins and the water from the elevated heat flux associated with active lithospheric extension. This project represents an interdisciplinary aerogeophysical study to characterize the lithosphere of the West Antarctic rift system beneath critical regions of the WAIS. The objective is to determine the effects of the rift architect ure, as manifested by the distribution of sedimentary basins and volcanic constructs, on the ice stream system. The research tool is a unique geophysical aircraft with laser altimetry, ice penetrating radar, aerogravity, and aeromagnetic systems integrated with a high precision kinematic GPS navigation system. It is capable of imaging both the surface and bed of the ice sheet while simultaneously measuring the gravity and magnetic signature of the subglacial lithosphere. Work to be done under this award will build on work already completed in the southern sector of central West Antarctica and it will focus on the region of the Byrd Subglacial Basin and Ice Stream D. The ice sheet in these regions is completely covered by satellite imagery and so this project will be integrated with remote sensing studies of the ice stream. The changing dynamics of Ice Stream D, as with other West Antarctic ice streams, seem to be correlated with changes in the morphological provinces of the underlying rift system. The experimental targets proceed from the divide of the interior ice, downstream through the onset of streaming to the trunk of Ice Stream D. This study will be coordinated with surface glaciological investigations of Ice Stream D and will be used to guide cooperative over-snow seismic investigations of the central West Antarctic rift system. The data will also be used to select a site for future deep ice coring along the crest of the WAIS. These data represent baseline data for long term global change monitoring work and represent crucial boundary conditions for ice sheet modeling efforts.", "east": -105.0, "geometry": "POINT(-130 -81)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS", "is_usap_dc": true, "keywords": "USAP-DC; MAGNETIC FIELD; GRAVITY FIELD; Antarctica; GLACIERS/ICE SHEETS; Marie Byrd Land; Airborne Gravity", "locations": "Marie Byrd Land; Antarctica", "north": -77.5, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Glaciology", "paleo_time": null, "persons": "Bell, Robin; Blankenship, Donald D.; Finn, C. A.", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -84.5, "title": "Collaborative Research: Lithospheric Controls on the Behavior of the West Antarctic Ice Sheet: Corridor Aerogeophysics of Eastern Ross Transect Zone", "uid": "p0010094", "west": -155.0}, {"awards": "1341602 Crockett, Elizabeth; 1341663 O\u0027Brien, Kristin", "bounds_geometry": null, "dataset_titles": "Acclimation of cardiovascular function in Notothenia coriiceps; Adrenergic and adenosinergic regulation of the cardiovascular system in the Antarctic icefish Chaenocephalus aceratus; Cardiac metabolism in Antarctic fishes in response to an acute increase in temperature; Chaenocephalus aceratus HIF-1A mRNA, complete cds; Chionodraco rastrospinosus HIF-1A mRNA, partial cds; Effects of acute warming on cardiovascular performance of Antarctic fishes; Eleginops maclovinus HIF-1A mRNA, partial cds; Gymnodraco acuticeps HIF-1A mRNA, partial cds; Hypoxia response of hearts of Antarctic fishes; Maximum cardiac performance of Antarctic fishes that lack haemoglobin and myoglobin: exploring the effect of warming on nature\u2019s natural knockouts; Measurements of splenic contraction in Antarctic fishes; Mitochondrial membranes in cardiac muscle from Antarctic notothenioid fishes vary in phospholipid composition and membrane fluidity; Notothenia coriiceps HIF-1A mRNA, complete cds; Parachaenichthys charcoti HIF-1A mRNA, partial cds; Physical, chemical, and functional properties of neuronal membranes vary between species of Antarctic notothenioids differing in thermal tolerance; Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin", "datasets": [{"dataset_uid": "601410", "doi": "10.15784/601410", "keywords": "Antarctica; Antarctic Peninsula; Biota; Fish", "people": "O\u0027Brien, Kristin; Crockett, Elizabeth; Egginton, Stuart; Axelsson, Michael; Farrell, Anthony; Joyce, William", "repository": "USAP-DC", "science_program": null, "title": "Effects of acute warming on cardiovascular performance of Antarctic fishes", "url": "https://www.usap-dc.org/view/dataset/601410"}, {"dataset_uid": "200189", "doi": null, "keywords": null, "people": null, "repository": "GenBank", "science_program": null, "title": "Eleginops maclovinus HIF-1A mRNA, partial cds", "url": "https://www.ncbi.nlm.nih.gov/nuccore/KX950830"}, {"dataset_uid": "601407", "doi": "10.15784/601407", "keywords": "Antarctica; Antarctic Peninsula", "people": "Axelsson, Michael; Joyce, William; O\u0027Brien, Kristin", "repository": "USAP-DC", "science_program": null, "title": "Measurements of splenic contraction in Antarctic fishes", "url": "https://www.usap-dc.org/view/dataset/601407"}, {"dataset_uid": "200184", "doi": "10.5061/dryad.83vc5", "keywords": null, "people": null, "repository": "Dryad", "science_program": null, "title": "Maximum cardiac performance of Antarctic fishes that lack haemoglobin and myoglobin: exploring the effect of warming on nature\u2019s natural knockouts", "url": "https://doi.org/10.5061/dryad.83vc5"}, {"dataset_uid": "200185", "doi": "10.5061/dryad.k90h35k", "keywords": null, "people": null, "repository": "Dryad", "science_program": null, "title": "Mitochondrial membranes in cardiac muscle from Antarctic notothenioid fishes vary in phospholipid composition and membrane fluidity", "url": "https://doi.org/10.5061/dryad.k90h35k"}, {"dataset_uid": "200186", "doi": "10.5061/dryad.qm0b25h", "keywords": null, "people": null, "repository": "Dryad", "science_program": null, "title": "Physical, chemical, and functional properties of neuronal membranes vary between species of Antarctic notothenioids differing in thermal tolerance", "url": "https://doi.org/10.5061/dryad.qm0b25h"}, {"dataset_uid": "200187", "doi": null, "keywords": null, "people": null, "repository": "GenBank", "science_program": null, "title": "Chaenocephalus aceratus HIF-1A mRNA, complete cds", "url": "https://www.ncbi.nlm.nih.gov/nuccore/KX950828"}, {"dataset_uid": "601408", "doi": "10.15784/601408", "keywords": "Antarctica; Antarctic Peninsula", "people": "Farrell, Anthony; Crockett, Elizabeth; Axelsson, Michael; O\u0027Brien, Kristin; Egginton, Stuart; Joyce, William", "repository": "USAP-DC", "science_program": null, "title": "Acclimation of cardiovascular function in Notothenia coriiceps", "url": "https://www.usap-dc.org/view/dataset/601408"}, {"dataset_uid": "200188", "doi": null, "keywords": null, "people": null, "repository": "GenBank", "science_program": null, "title": "Notothenia coriiceps HIF-1A mRNA, complete cds", "url": "https://www.ncbi.nlm.nih.gov/nuccore/KX950829"}, {"dataset_uid": "601409", "doi": "10.15784/601409", "keywords": "Antarctica; Antarctic Peninsula", "people": "Joyce, Michael; O\u0027Brien, Kristin; Egginton, Stuart; Farrell, Anthony; Axelsson, Michael", "repository": "USAP-DC", "science_program": null, "title": "Adrenergic and adenosinergic regulation of the cardiovascular system in the Antarctic icefish Chaenocephalus aceratus", "url": "https://www.usap-dc.org/view/dataset/601409"}, {"dataset_uid": "601414", "doi": "10.15784/601414", "keywords": "Antarctica; Antarctic Peninsula", "people": "Evans, Elizabeth; Farnoud, Amir; Crockett, Elizabeth; O\u0027Brien, Kristin", "repository": "USAP-DC", "science_program": null, "title": "Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin", "url": "https://www.usap-dc.org/view/dataset/601414"}, {"dataset_uid": "200190", "doi": null, "keywords": null, "people": null, "repository": "GenBank", "science_program": null, "title": "Parachaenichthys charcoti HIF-1A mRNA, partial cds", "url": "https://www.ncbi.nlm.nih.gov/nuccore/KX950833"}, {"dataset_uid": "601405", "doi": "10.15784/601405", "keywords": "Antarctica; Antarctic Peninsula", "people": "O\u0027Brien, Kristin", "repository": "USAP-DC", "science_program": null, "title": "Cardiac metabolism in Antarctic fishes in response to an acute increase in temperature", "url": "https://www.usap-dc.org/view/dataset/601405"}, {"dataset_uid": "200191", "doi": null, "keywords": null, "people": null, "repository": "GenBank", "science_program": null, "title": "Gymnodraco acuticeps HIF-1A mRNA, partial cds", "url": "https://www.ncbi.nlm.nih.gov/nuccore/kx950832"}, {"dataset_uid": "200192", "doi": null, "keywords": null, "people": null, "repository": "GenBank", "science_program": null, "title": "Chionodraco rastrospinosus HIF-1A mRNA, partial cds", "url": "https://www.ncbi.nlm.nih.gov/nuccore/kx950831"}, {"dataset_uid": "601406", "doi": "10.15784/601406", "keywords": "Antarctica; Antarctic Peninsula", "people": "O\u0027Brien, Kristin", "repository": "USAP-DC", "science_program": null, "title": "Hypoxia response of hearts of Antarctic fishes", "url": "https://www.usap-dc.org/view/dataset/601406"}], "date_created": "Wed, 26 Feb 2020 00:00:00 GMT", "description": "The ocean surrounding Antarctica is home to an extraordinary assemblage of fishes, dominated by a single group that are extremely well-suited to life in icy waters and which are of significant ecological importance there. Of great concern is the capacity of these fishes to withstand increases in temperature as the region of the Western Antarctic Peninsula warms at a rate faster than any other area in the Southern hemisphere. One particular group of Antarctic fishes, known as the icefishes, are particularly vulnerable to increases in temperature because unlike all other vertebrates on earth, icefishes are white-blooded due to their lack of the oxygen-binding protein hemoglobin. This greatly reduces their capacity to transport and deliver oxygen to tissues compared to red-blooded Antarctic fishes. Previous studies have shown that icefishes are indeed less tolerant to elevations in temperature but the underlying factors are completely unknown. Additionally, it is not understood if red- or white-blooded Antarctic fishes can adjust, or acclimate, to modest increases in temperature, similar to those changes in temperature the animals might experience as the earth warms. The investigators will determine if heart function and/or nervous system function limits thermal tolerance of Antarctic fishes, and will determine their capacity to acclimate to warmer temperatures. The project will further the NSF goal of training new generations of scientists by training graduate and undergraduate students. In addition, the project will collaborate with a high school biology teacher from a school which serves a largely minority student body. The students will learn about the marine environment, and will construct a camera to be used in the field to learn more about Antarctic fishes. Two students and the teacher will also attend a summer marine biology internship program. Antarctic fishes within the suborder Notothenioidei (called \"notothenioids\") are among the organisms on earth least able to deal with changes in temperature. The hemoglobinless icefish are even less able to withstand temperature changes than are red-blooded notothenioids. While this is well documented, the underlying physiological and biochemical mechanisms responsible are unknown. The investigators will test the hypotheses that cardiac work is significantly greater in icefishes compared to red-blooded species, and that as temperature increases, the greater cardiac work of icefishes, coupled with reduced blood oxygen-carrying capacity, results in cardiac failure at a lower temperature compared to red-blooded species. They also hypothesize that neuronal function limits thermal tolerance of red-blooded notothenioids. These hypotheses will be tested using a wide variety of experiments. For example, the investigators will measure heart rate concurrently with critical thermal maximum. They will also characterize metabolic and gene-expression responses to elevated temperature and determine if mitochondrial function contributes to thermal tolerance using a variety of techniques. To determine if neuronal function limits thermal tolerance they will quantify behavioral responses to warming of whole animals and to warming of only the brain area. They will also determine if acclimation to warmer temperatures impacts heart function and they will measure activities of a variety of enzymes from central metabolic pathways.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "Antarctica; Amd/Us; FISH; USA/NSF; FIELD INVESTIGATION; AMD; Antarctic Peninsula; LABORATORY; USAP-DC", "locations": "Antarctica; Antarctic Peninsula", "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Crockett, Elizabeth; O\u0027Brien, Kristin", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "Dryad; GenBank; USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: The Physiological and Biochemical Underpinnings of Thermal Tolerance in Antarctic Notothenioid Fishes", "uid": "p0010084", "west": null}, {"awards": "1246111 Dalziel, Ian", "bounds_geometry": "POLYGON((-44 -53,-42.9 -53,-41.8 -53,-40.7 -53,-39.6 -53,-38.5 -53,-37.4 -53,-36.3 -53,-35.2 -53,-34.1 -53,-33 -53,-33 -53.4,-33 -53.8,-33 -54.2,-33 -54.6,-33 -55,-33 -55.4,-33 -55.8,-33 -56.2,-33 -56.6,-33 -57,-34.1 -57,-35.2 -57,-36.3 -57,-37.4 -57,-38.5 -57,-39.6 -57,-40.7 -57,-41.8 -57,-42.9 -57,-44 -57,-44 -56.6,-44 -56.2,-44 -55.8,-44 -55.4,-44 -55,-44 -54.6,-44 -54.2,-44 -53.8,-44 -53.4,-44 -53))", "dataset_titles": "BAS Geological Collection: Central Scotia Sea (full data link not provided); Nathaniel B Palmer NBP 1408; South Georgia: SOG1, SOG2, SOG3", "datasets": [{"dataset_uid": "200107", "doi": "", "keywords": null, "people": null, "repository": "British Antarctic Survey", "science_program": null, "title": "BAS Geological Collection: Central Scotia Sea (full data link not provided)", "url": "https://www.bas.ac.uk/data/our-data/collections/geological-collections/"}, {"dataset_uid": "200106", "doi": "", "keywords": null, "people": null, "repository": "MGDS", "science_program": null, "title": "Nathaniel B Palmer NBP 1408", "url": "http://www.marine-geo.org/tools/search/entry.php?id=NBP1408"}, {"dataset_uid": "200105", "doi": "", "keywords": null, "people": null, "repository": "UNAVCO", "science_program": null, "title": "South Georgia: SOG1, SOG2, SOG3", "url": "https://www.unavco.org/data/gps-gnss/gps-gnss.html"}], "date_created": "Tue, 28 Jan 2020 00:00:00 GMT", "description": "Intellectual Merit: Opening of Drake Passage and the West Scotia Sea south of Tierra del Fuego broke the final continental barrier to onset of a complete Antarctic Circumpolar Current (ACC). Initiation of the ACC has been associated in time with a major, abrupt, drop in global temperatures and the rapid expansion of the Antarctic ice sheets at 33-34 Ma. Events leading to the formation of the Drake Passage gateway are poorly known. Understanding the tectonic evolution of the floor of the Central Scotia Sea (CSS) and the North Scotia Ridge is a key to this understanding. Previous work has demonstrated that superimposed constructs formed a volcanic arc that likely blocked direct eastward flow from the Pacific to the Atlantic through the opening Drake Passage gateway as the active South Sandwich arc does today. The PIs propose a cruise to test, develop and refine, with further targeted mapping and dredging, their theory of CSS tectonics and the influence it had on the onset and development of the ACC. In addition they propose an installation of GPS receiver to test their paleogeographic reconstructions and determine whether South Georgia is moving as part of the South American plate. Broader impacts: A graduate student will be involved in all stages of the research. Undergraduate students will also be involved as watch-standers. A community college teacher will participate in the cruise. The PIs will have a website on which there will be images of the actual ocean floor dredging in operation. The teacher will participate with web and outreach support through PolarTREC. Results of the cruise are of broad interest to paleoceanographers, paleoclimate modelers and paleobiogeographers.", "east": -33.0, "geometry": "POINT(-38.5 -55)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "Scotia Sea; PLATE BOUNDARIES; TECTONIC PROCESSES; NOT APPLICABLE; COASTAL ELEVATION; Southern Ocean; USAP-DC", "locations": "Scotia Sea; Southern Ocean", "north": -53.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Glaciology", "paleo_time": null, "persons": "Dalziel, Ian W.; Lawver, Lawrence; Krissek, Lawrence", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "British Antarctic Survey", "repositories": "British Antarctic Survey; MGDS; UNAVCO", "science_programs": null, "south": -57.0, "title": "Collaborative Research: Role of the Central Scotia Sea Floor and North Scotia Ridge in the Onset and Development of the Antarctic Circumpolar Current", "uid": "p0010078", "west": -44.0}, {"awards": "1444167 Detrich, H. William", "bounds_geometry": "POLYGON((-70 -58,-68.5 -58,-67 -58,-65.5 -58,-64 -58,-62.5 -58,-61 -58,-59.5 -58,-58 -58,-56.5 -58,-55 -58,-55 -59.8,-55 -61.6,-55 -63.4,-55 -65.2,-55 -67,-55 -68.8,-55 -70.6,-55 -72.4,-55 -74.2,-55 -76,-56.5 -76,-58 -76,-59.5 -76,-61 -76,-62.5 -76,-64 -76,-65.5 -76,-67 -76,-68.5 -76,-70 -76,-70 -74.2,-70 -72.4,-70 -70.6,-70 -68.8,-70 -67,-70 -65.2,-70 -63.4,-70 -61.6,-70 -59.8,-70 -58))", "dataset_titles": "Assembled Contig Dat for Daane et al. (2019); E-MTAB-6759: RNA-seq across tissues in four Notothenioid species (Antarctic icefish); Expedition Data of LMG1603; Expedition Data of LMG1604; Expedition Data of LMG1605; Expedition Data of LMG1803; Expedition Data of LMG1804; Expedition Data of LMG1805; Full raw data set, computer code, and evolutionary trajectories for all species in Damsgaard et al. (2019); Histology-, CT-, ultrasound-, and MRI-scans (~2 TB) for Damsgaard et al. (2019); PRJNA420419: Genome and Transcriptome Data for Kim et al. (2019) Blackfin Icefish Genome; PRJNA531677: Sequencing Data for Daane et al. (2019); S-BSST132: Assembled Transcriptomes for Berthelot et al. (2018); SRP047484 RAD-tag Sequences of Genetically Mapped Notothenia coriiceps embryos; SRP118539: RAD-tag Sequences of Genetically Mapped Chaenocephalus aceratus Embryos; Transposable element sequences and genome sizes, refs 142597 to MF142757", "datasets": [{"dataset_uid": "200252", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG1604", "url": "https://www.rvdata.us/search/cruise/LMG1604"}, {"dataset_uid": "200094", "doi": "", "keywords": null, "people": null, "repository": "Array Express", "science_program": null, "title": "E-MTAB-6759: RNA-seq across tissues in four Notothenioid species (Antarctic icefish)", "url": "https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-6759/"}, {"dataset_uid": "200096", "doi": "", "keywords": null, "people": null, "repository": "NCBI SRA", "science_program": null, "title": "SRP047484 RAD-tag Sequences of Genetically Mapped Notothenia coriiceps embryos", "url": "https://www.ncbi.nlm.nih.gov/sra/?term=SRP047484"}, {"dataset_uid": "200098", "doi": "", "keywords": null, "people": null, "repository": "NCBI BioProject", "science_program": null, "title": "PRJNA531677: Sequencing Data for Daane et al. (2019)", "url": "https://www.ncbi.nlm.nih.gov/bioproject/PRJNA531677"}, {"dataset_uid": "200253", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG1605", "url": "https://www.rvdata.us/search/cruise/LMG1605"}, {"dataset_uid": "200095", "doi": "", "keywords": null, "people": null, "repository": "BioStudies", "science_program": null, "title": "S-BSST132: Assembled Transcriptomes for Berthelot et al. (2018)", "url": "https://www.ebi.ac.uk/biostudies/studies/S-BSST132"}, {"dataset_uid": "200092", "doi": "", "keywords": null, "people": null, "repository": "NCBI BioProject", "science_program": null, "title": "PRJNA420419: Genome and Transcriptome Data for Kim et al. (2019) Blackfin Icefish Genome", "url": "https://www.ncbi.nlm.nih.gov/bioproject/?term=prjna420419"}, {"dataset_uid": "200093", "doi": "", "keywords": null, "people": null, "repository": "NCBI SRA", "science_program": null, "title": "SRP118539: RAD-tag Sequences of Genetically Mapped Chaenocephalus aceratus Embryos", "url": "https://www.ncbi.nlm.nih.gov/sra/SRP118539 "}, {"dataset_uid": "200102", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "Transposable element sequences and genome sizes, refs 142597 to MF142757", "url": "https://www.ncbi.nlm.nih.gov/nuccore?LinkName=pubmed_nuccore\u0026from_uid=29739320"}, {"dataset_uid": "200103", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Full raw data set, computer code, and evolutionary trajectories for all species in Damsgaard et al. (2019)", "url": "https://github.com/elifesciences-publications/Retinaevolution"}, {"dataset_uid": "200104", "doi": "", "keywords": null, "people": null, "repository": "eLife", "science_program": null, "title": "Histology-, CT-, ultrasound-, and MRI-scans (~2 TB) for Damsgaard et al. (2019)", "url": "https://retinaevolution.bios.au.dk/eLife%20documentation/README.txt"}, {"dataset_uid": "200251", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG1804", "url": "https://www.rvdata.us/search/cruise/LMG1804"}, {"dataset_uid": "200250", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG1603", "url": "https://www.rvdata.us/search/cruise/LMG1603"}, {"dataset_uid": "200249", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG1803", "url": "https://www.rvdata.us/search/cruise/LMG1803"}, {"dataset_uid": "200099", "doi": "10.5281/zenodo.2628936", "keywords": null, "people": null, "repository": "Zenodo", "science_program": null, "title": "Assembled Contig Dat for Daane et al. (2019)", "url": "https://zenodo.org/record/2628936#.Xegqj3dFw2w"}, {"dataset_uid": "200254", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG1805", "url": "https://www.rvdata.us/search/cruise/LMG1805"}], "date_created": "Wed, 04 Dec 2019 00:00:00 GMT", "description": "Antarctic fish and their early developmental stages are an important component of the food web that sustains life in the cold Southern Ocean (SO) that surrounds Antarctica. They feed on smaller organisms and in turn are eaten by larger animals, including seals and killer whales. Little is known about how rising ocean temperatures will impact the development of Antarctic fish embryos and their growth after hatching. This project will address this gap by assessing the effects of elevated temperatures on embryo viability, on the rate of embryo development, and on the gene \"toolkits\" that respond to temperature stress. One of the two species to be studied does not produce red blood cells, a defect that may make its embryos particularly vulnerable to heat. The outcomes of this research will provide the public and policymakers with \"real world\" data that are necessary to inform decisions and design strategies to cope with changes in the Earth\u0027s climate, particularly with respect to protecting life in the SO. The project will also further the NSF goals of training new generations of scientists, including providing scientific training for undergraduate and graduate students, and of making scientific discoveries available to the general public. This includes the unique educational opportunity for undergraduates to participate in research in Antarctica and engaging the public in several ways, including the development of professionally-produced educational videos with bi-lingual closed captioning. Since the onset of cooling of the SO about 40 million years ago, evolution of Antarctic marine organisms has been driven by the development of cold temperatures. Because body temperatures of Antarctic fishes fall in a narrow range determined by their habitat (-1.9 to +2.0 C) they are particularly attractive models for understanding how organismal physiology and biochemistry have been shaped to maintain life in a cooling environment. The long-term objective of this project is to understand the capacities of Antarctic fishes to acclimatize and/or adapt to rapid oceanic warming through analysis of their underlying genetic \"toolkits.\" This objective will be accomplished through three Specific Aims: 1) assessing the effects of elevated temperatures on gene expression during development of embryos; 2) examining the effects of elevated temperatures on embryonic morphology and on the temporal and spatial patterns of gene expression; and 3) evaluating the evolutionary mechanisms that have led to the loss of the red blood cell genetic program by the white-blooded fishes. Aims 1 and 2 will be investigated by acclimating experimental embryos of both red-blooded and white-blooded fish to elevated temperatures. Differential gene expression will be examined through the use of high throughput RNA sequencing. The temporal and spatial patterns of gene expression in the context of embryonic morphology (Aim 2) will be determined by microscopic analysis of embryos \"stained\" with (hybridized to) differentially expressed gene probes revealed by Aim 1; other developmental marker genes will also be used. The genetic lesions resulting from loss of red blood cells by the white-blooded fishes (Aim 3) will be examined by comparing genes and genomes in the two fish groups.", "east": -55.0, "geometry": "POINT(-62.5 -67)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "NOT APPLICABLE; Polar; South Shetland Islands; USAP-DC; COASTAL", "locations": "Polar; South Shetland Islands", "north": -58.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Detrich, H. William", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "R2R", "repositories": "Array Express; BioStudies; eLife; GitHub; NCBI BioProject; NCBI GenBank; NCBI SRA; R2R; Zenodo", "science_programs": null, "south": -76.0, "title": "Antarctic Notothenioid Fishes: Sentinel Taxa for Southern Ocean Warming", "uid": "p0010073", "west": -70.0}, {"awards": "1643735 Li, Yun; 1643901 Zhang, Weifeng; 2021245 Li, Yun", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": "Dynamic fine-scale sea-icescape shapes adult emperor penguin foraging habitat in East Antarctica; Monthly Stratification Climatology (1978-2021) in Antarctic Coastal Polynyas", "datasets": [{"dataset_uid": "601209", "doi": "10.15784/601209", "keywords": "Animal Behavior Observation; Antarctica; Biota; East Antarctica; GPS; Oceans; Penguin; Southern Ocean", "people": "Pinaud, David; Wienecke, Barbara; Kirkwood, Roger; Ropert-Coudert, Yan; Resinger, Ryan; Jonsen, Ian; Porter-Smith, Rick; Barbraud, Christophe; Ji, Rubao; Jenouvrier, Stephanie; Sumner, Michael; Bost, Charles-Andr\u00e9; Labrousse, Sara; Fraser, Alexander; Tamura, Takeshi", "repository": "USAP-DC", "science_program": null, "title": "Dynamic fine-scale sea-icescape shapes adult emperor penguin foraging habitat in East Antarctica", "url": "https://www.usap-dc.org/view/dataset/601209"}, {"dataset_uid": "601628", "doi": "10.15784/601628", "keywords": "Antarctic; Antarctica; Antarctic Coastal Polynyas; Polynya", "people": "Zhang, Weifeng; Shunk, Nathan; Li, Yun", "repository": "USAP-DC", "science_program": null, "title": "Monthly Stratification Climatology (1978-2021) in Antarctic Coastal Polynyas", "url": "https://www.usap-dc.org/view/dataset/601628"}], "date_created": "Wed, 07 Aug 2019 00:00:00 GMT", "description": "During winter, sea-ice coverage along the Antarctic coast is punctuated by numerous polynyas--isolated openings of tens to hundreds of kilometer wide. These coastal polynyas are hotspots of sea ice production and the primary source regions of the bottom water in the global ocean. They also host high levels of biological activities and are the feeding grounds of Emperor penguins and marine mammals. The polynyas are a key component of the Antarctic coastal system and crucial for the survival of penguins and many other species. These features also differ dramatically from each other in timing of formation, duration, phytoplankton growth season, and overall biological productivity. Yet, the underlying reasons for differences among them are largely unknown. This project studies the fundamental biophysical processes at a variety of polynyas, examines the connection between the physical environment and the phytoplankton and penguin ecology, and investigates the mechanisms behind polynya variability. The results of this interdisciplinary study will provide a context for interpretation of field measurements in Antarctic coastal polynyas, set a baseline for future polynya studies, and examine how polynya ecosystems may respond to local and large-scale environmental changes. The project will include educational and outreach activities that convey scientific messages to a broad audience. It aims to increase public awareness of the interconnection between large-scale environmental change and Antarctic coastal systems. The main objectives of this study are to form a comprehensive understanding of the temporal and spatial variability of Antarctic coastal polynyas and the physical controls of polynya ecosystems. The project takes an interdisciplinary approach and seeks to establish a modeling system centered on the Regional Ocean Modeling System. This system links the ice and ocean conditions to the plankton ecology and penguin population. Applications of the modeling system in representative polynyas, in conjunction with analysis of existing observations, will determine the biophysical influences of individual forcing factors. In particular, this study will test a set of hypothesized effects of winds, offshore water intrusion, ice-shelf melting, sea-ice formation, glacier tongues, and ocean stratification on the timing of polynya phytoplankton bloom and the overall polynya biological productivity. The project will also examine how changing polynya state affects penguin breeding success, adult survival, and population growth. The team will conduct idealized sensitivity analysis to explore implications of forcing variability, including local and large-scale environmental change, on Antarctic coastal ecosystems.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "Southern Ocean; Animal Behavior; Penguin; FIELD INVESTIGATION; USAP-DC; COASTAL; PENGUINS; SEA ICE; Antarctica; OCEAN MIXED LAYER", "locations": "Southern Ocean; Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Integrated System Science; Antarctic Integrated System Science; Antarctic Ocean and Atmospheric Sciences; Antarctic Ocean and Atmospheric Sciences; Antarctic Integrated System Science", "paleo_time": null, "persons": "Zhang, Weifeng; Ji, Rubao; Jenouvrier, Stephanie; Maksym, Edward; Li, Yun", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Collaborative Research: Polynyas in Coastal Antarctica (PICA): Linking Physical Dynamics to Biological Variability", "uid": "p0010044", "west": -180.0}, {"awards": "1247510 Detrich, H. William", "bounds_geometry": null, "dataset_titles": "E-MTAB-6759: RNA-seq across tissues in four Notothenioid species (Antarctic icefish); Expedition Data; Expedition data of LMG1003; Expedition data of LMG1004; PRJNA420419: Chaenocephalus aceratus Genome sequencing; PRJNA66471: Notothenia coriiceps Genome Sequencing Notothenia coriiceps isolate:Sejong01 (black rockcod); S-BSST 132: Assembled Transcriptomes for Berthelot et al. (2018); SRA091269: Notothenia coriiceps RNA Raw Sequence Reads; SRP047484: RAD-tag Sequences of Genetically Mapped Notothenia coriiceps Embryos ; SRP118539: RAD-tag Sequences of Genetically Mapped Chaenocephalus aceratus Embryos", "datasets": [{"dataset_uid": "200026", "doi": "", "keywords": null, "people": null, "repository": "NCBI SRA", "science_program": null, "title": "SRA091269: Notothenia coriiceps RNA Raw Sequence Reads", "url": "https://www.ncbi.nlm.nih.gov/sra/?term=SRA091269"}, {"dataset_uid": "200146", "doi": "", "keywords": null, "people": null, "repository": "NCBI SRA", "science_program": null, "title": "SRP047484: RAD-tag Sequences of Genetically Mapped Notothenia coriiceps Embryos ", "url": "https://www.ncbi.nlm.nih.gov/sra/?term=SRP047484"}, {"dataset_uid": "200145", "doi": "", "keywords": null, "people": null, "repository": "BioStudies", "science_program": null, "title": "S-BSST 132: Assembled Transcriptomes for Berthelot et al. (2018)", "url": "https://www.ebi.ac.uk/biostudies/studies/S-BSST132"}, {"dataset_uid": "200144", "doi": "", "keywords": null, "people": null, "repository": "Array Express", "science_program": null, "title": "E-MTAB-6759: RNA-seq across tissues in four Notothenioid species (Antarctic icefish)", "url": "https://www.ebi.ac.uk/arrayexpress/experiments/E-MTAB-6759/"}, {"dataset_uid": "200143", "doi": "", "keywords": null, "people": null, "repository": "NCBI BioProject", "science_program": null, "title": "PRJNA420419: Chaenocephalus aceratus Genome sequencing", "url": "https://www.ncbi.nlm.nih.gov/bioproject/420419"}, {"dataset_uid": "001508", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0807"}, {"dataset_uid": "200142", "doi": "", "keywords": null, "people": null, "repository": "NCBI BioProject", "science_program": null, "title": "PRJNA66471: Notothenia coriiceps Genome Sequencing Notothenia coriiceps isolate:Sejong01 (black rockcod)", "url": "https://www.ncbi.nlm.nih.gov/bioproject/66471"}, {"dataset_uid": "200093", "doi": "", "keywords": null, "people": null, "repository": "NCBI SRA", "science_program": null, "title": "SRP118539: RAD-tag Sequences of Genetically Mapped Chaenocephalus aceratus Embryos", "url": "https://www.ncbi.nlm.nih.gov/sra/SRP118539 "}, {"dataset_uid": "002685", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1004", "url": "https://www.rvdata.us/search/cruise/LMG1004"}, {"dataset_uid": "002684", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1003", "url": "https://www.rvdata.us/search/cruise/LMG1003"}, {"dataset_uid": "001509", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0806"}], "date_created": "Mon, 08 Apr 2019 00:00:00 GMT", "description": "Since the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~40-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. As circum-Antarctic coastal temperatures declined during this period from ~20\u00b0C to the modern ?1.9 to +2.0\u00b0C (reached ~8-10 million years ago), the psychrophilic (cold-loving) ectotherms of the Southern Ocean evolved compensatory molecular, cellular, and physiological traits that enabled them to maintain normal metabolic function at cold temperatures. Today, these organisms are threatened by rapid warming of the Southern Ocean over periods measured in centuries (as much as 5\u00b0C/100 yr), a timeframe so short that re-adaptation and/or acclimatization to the ?new warm? may not be possible. Thus, the long-term goals of this research project are: 1) to understand the biochemical and physiological capacities of the embryos of Antarctic notothenioid fish to resist or compensate for rapid oceanic warming; and 2) to assess the genetic toolkit available to support the acclimatization and adaptation of Antarctic notothenioid embryos to their warming habitat. The specific aims of this work are: 1) to determine the capacity of the chaperonin complex of notothenioid fishes to assist protein folding at temperatures between ?4 and +20\u00b0C; and 2) to evaluate the genetic responses of notothenioid embryos, measured as global differential gene transcription, to temperature challenge, with ?1.9\u00b0C as the ?normal? control and +4 and +10\u00b0C as high temperature insults. The physiology of embryonic development of marine stenotherms under future climate change scenarios is an important but understudied problem. This project will provide valuable insights into the capacity of Antarctic fish embryos to acclimatize and adapt to plausible climate change scenarios by examining multiple levels of biological organization, from the biochemical to the organismal. The results should also be broadly applicable to understanding the impact of global warming on marine biota worldwide. The research will also introduce graduate and REU undergraduate students to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SAMPLERS \u003e TRAWLS/NETS \u003e BOTTOM TRAWL", "is_usap_dc": false, "keywords": "AQUATIC SCIENCES; R/V LMG; USAP-DC; Southern Ocean", "locations": "Southern Ocean", "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Detrich, H. William", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "NCBI SRA", "repositories": "Array Express; BioStudies; NCBI BioProject; NCBI SRA; R2R", "science_programs": null, "south": null, "title": "Protein Folding and Embryogenesis in Antarctic Fishes: A Comparative Approach to Environmental Stress", "uid": "p0010024", "west": null}, {"awards": "1246045 Waddington, Edwin", "bounds_geometry": "POLYGON((-180 -70,-144 -70,-108 -70,-72 -70,-36 -70,0 -70,36 -70,72 -70,108 -70,144 -70,180 -70,180 -72,180 -74,180 -76,180 -78,180 -80,180 -82,180 -84,180 -86,180 -88,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -88,-180 -86,-180 -84,-180 -82,-180 -80,-180 -78,-180 -76,-180 -74,-180 -72,-180 -70))", "dataset_titles": "Code for inference of fabric from sonic velocity and thin-section measurements.; Code for models involving stochastic treatment of ice fabric", "datasets": [{"dataset_uid": "000244", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Code for models involving stochastic treatment of ice fabric", "url": "https://github.com/mjhay/stochastic_fabric"}, {"dataset_uid": "000243", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Code for inference of fabric from sonic velocity and thin-section measurements.", "url": "https://github.com/mjhay/neem_sonic_model"}], "date_created": "Mon, 02 Apr 2018 00:00:00 GMT", "description": "Waddington/1246045 This award supports a project to investigate the onset and growth of folds and other disturbances seen in the stratigraphic layers of polar ice sheets. The intellectual merit of the work is that it will lead to a better understanding of the grain-scale processes that control the development of these stratigraphic features in the ice and will help answer questions such as what processes can initiate such disturbances. Snow is deposited on polar ice sheets in layers that are generally flat, with thicknesses that vary slowly along the layers. However, ice cores and ice-penetrating radar show that in some cases, after conversion to ice, and following lengthy burial, the layers can become folded, develop pinch-and-swell structures (boudinage), and be sheared by ice flow, at scales ranging from centimeters to hundreds of meters. The processes causing these disturbances are still poorly understood. Disturbances appear to develop first at the ice-crystal scale, then cascade up to larger scales with continuing ice flow and strain. Crystal-scale processes causing distortions of cm-scale layers will be modeled using Elle, a microstructure-modeling package, and constrained by fabric thin-sections and grain-elongation measurements from the West Antarctic Ice Sheet divide ice-core. A full-stress continuum anisotropic ice-flow model coupled to an ice-fabric evolution model will be used to study bulk flow of anisotropic ice, to understand evolution and growth of flow disturbances on the meter and larger scale. Results from this study will assist in future ice-core site selection, and interpretation of stratigraphy in ice cores and radar, and will provide improved descriptions of rheology and stratigraphy for ice-sheet flow models.The broader impacts are that it will bring greater understanding to ice dynamics responsible for stratigraphic disturbance. This information is valuable to constrain depth-age relationships in ice cores for paleoclimate study. This will allow researchers to put current climate change in a more accurate context. This project will provide three years of support for a graduate student as well as support and research experience for an undergraduate research assistant; this will contribute to development of talent needed to address important future questions in glaciology and climate change. The research will be communicated to the public through outreach events and results from the study will be disseminated through public and professional meetings as well as journal publications. The project does not require field work in Antarctica.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "NOT APPLICABLE; USAP-DC", "locations": null, "north": -70.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Waddington, Edwin D.", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "GitHub", "repositories": "GitHub", "science_programs": null, "south": -90.0, "title": "Anisotropic Ice and Stratigraphic Disturbances", "uid": "p0000073", "west": -180.0}, {"awards": "1246317 Mittal, Rajat; 1246296 Yen, Jeannette", "bounds_geometry": null, "dataset_titles": "Hydrodynamics of Spongiobranchaea australis; Tomographic PIV measurements of swimming shelled Antarctic pteropod", "datasets": [{"dataset_uid": "601058", "doi": "10.15784/601058", "keywords": "Biota; Fish; Southern Ocean", "people": "Mittal, Rajat", "repository": "USAP-DC", "science_program": null, "title": "Hydrodynamics of Spongiobranchaea australis", "url": "https://www.usap-dc.org/view/dataset/601058"}, {"dataset_uid": "601108", "doi": "10.15784/601108", "keywords": "Antarctica; Biota; Glaciology", "people": "Yen, Jeannette; Adhikari, Deepak; Webster, Donald R", "repository": "USAP-DC", "science_program": null, "title": "Tomographic PIV measurements of swimming shelled Antarctic pteropod", "url": "https://www.usap-dc.org/view/dataset/601108"}], "date_created": "Fri, 29 Sep 2017 00:00:00 GMT", "description": "Ocean acidification (OA) poses a serious threat, particularly to organisms that precipitate calcium carbonate from seawater. One organism with an aragonite shell that is a key to high latitude ecosystems is the pteropod. With OA, the pteropod shell will thin because the aragonite is highly soluble. As the shell thins, it changes the mass distribution and buoyancy of the animal, which will affect locomotion and through it, all locomotion dependent behavior such as foraging, mating, predator avoidance and migratory patterns. A lower shell weight will be counterbalanced by a smaller mucus web potentially decreasing ingestion rates and carbon flux rates. This interdisciplinary research relies on biological studies of swimming behavior of the pteropod mollusk Limacina helicina in their natural environments with fluid mechanics analyses of swimming hydrodynamics via 3D tomographic particle-image velocimetry and computational fluid dynamics (CFD). This work will: (a) determine how the L. helicina uses its \u0027wings\u0027 (parapodia) to propel itself; (b) examine whether its locomotory kinematics provide efficient propulsion; (c) identify the factors that influence swimming trajectory and \u0027wobble\u0027; and (d) synthesize all data and insights into guidelines for the potential use of pteropod swimming behavior as a bioassay for OA. The loss of these sentinels of anthropogenic increases in CO2 may result in an ecological shift since thecosome pteropods are responsible for ingesting nearly half the primary production in the Southern Ocean and also serve as a primary food resource to upper trophic levels like fish. Since locomotory data can be gathered immediately, the bioassay being developed in this proposal may serve as an early warning of the impending onset of OA effects on this important member of the plankton. Students and researchers will collaborate in a rich interdisciplinary research environment by working with a biological oceanographer, a fluid mechanics expert and a CFD expert coupled with the teamsmanship needed for work in the Antarctic. By setting up a one-of-a-kind 3D tomography system for visualizing flow around planktonic organisms in Norway and at Palmer Station, we increase international exchange of state-of-the-art techniques. The educational impact of the current research will be multiplied by including in the research team, undergraduate students, high-school students and underrepresented minorities in addition to graduate students.", "east": null, "geometry": null, "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "USAP-DC; NOT APPLICABLE; Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Yen, Jeannette; Mittal, Rajat; Webster, Donald R", "platforms": "Not provided; OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: Pteropod Swimming Behavior as a Bio Assay for Ocean Acidification", "uid": "p0000139", "west": null}, {"awards": "1245283 Passchier, Sandra", "bounds_geometry": "POLYGON((66 -68,67.3 -68,68.6 -68,69.9 -68,71.2 -68,72.5 -68,73.8 -68,75.1 -68,76.4 -68,77.7 -68,79 -68,79 -68.2,79 -68.4,79 -68.6,79 -68.8,79 -69,79 -69.2,79 -69.4,79 -69.6,79 -69.8,79 -70,77.7 -70,76.4 -70,75.1 -70,73.8 -70,72.5 -70,71.2 -70,69.9 -70,68.6 -70,67.3 -70,66 -70,66 -69.8,66 -69.6,66 -69.4,66 -69.2,66 -69,66 -68.8,66 -68.6,66 -68.4,66 -68.2,66 -68))", "dataset_titles": "Antarctic Geochemistry Data and Mean Annual Temperature Reconstruction through the Eocene-Oligocene Transition; GSA Data Repository Item 2016298 - Passchier, S., Ciarletta, D.J., Miriagos, T.E., Bijl, P.K., and Bohaty, S.M., 2016, An Antarctic stratigraphic record of step-wise ice growth through the Eocene-Oligocene transition: GSA Bulletin, doi:10.1130/B31482.1.; Particle-size distributions of Eocene-Oligocene sediment from ODP Site 739, Prydz Bay; Particle-size distributions of Eocene-Oligocene sediment from ODP Site 742, Prydz Bay; Particle-size distributions of Eocene sediment from ODP Site 1166, Prydz Bay", "datasets": [{"dataset_uid": "601454", "doi": "10.15784/601454", "keywords": "Antarctica; Eocene; Marine Geoscience; ODP742; Oligocene; Particle Size; Prydz Bay; Sediment Core Data", "people": "Passchier, Sandra; Ciarletta, Daniel", "repository": "USAP-DC", "science_program": null, "title": "Particle-size distributions of Eocene-Oligocene sediment from ODP Site 742, Prydz Bay", "url": "https://www.usap-dc.org/view/dataset/601454"}, {"dataset_uid": "200200", "doi": "10.1130/2016298", "keywords": null, "people": null, "repository": "Publication", "science_program": null, "title": " GSA Data Repository Item 2016298 - Passchier, S., Ciarletta, D.J., Miriagos, T.E., Bijl, P.K., and Bohaty, S.M., 2016, An Antarctic stratigraphic record of step-wise ice growth through the Eocene-Oligocene transition: GSA Bulletin, doi:10.1130/B31482.1.", "url": "https://gsapubs.figshare.com/articles/journal_contribution/Supplemental_material_An_Antarctic_stratigraphic_record_of_step-wise_ice_growth_through_the_Eocene-Oligocene_transition/12534185"}, {"dataset_uid": "601453", "doi": "10.15784/601453", "keywords": "Antarctica; Eocene; Marine Geoscience; ODP739; Oligocene; Particle Size; Prydz Bay; Sediment Core Data", "people": "Ciarletta, Daniel; Passchier, Sandra", "repository": "USAP-DC", "science_program": null, "title": "Particle-size distributions of Eocene-Oligocene sediment from ODP Site 739, Prydz Bay", "url": "https://www.usap-dc.org/view/dataset/601453"}, {"dataset_uid": "601455", "doi": "10.15784/601455", "keywords": "Antarctica; Eocene; Marine Geoscience; ODP1166; Particle Size; Prydz Bay; Sediment Core Data", "people": "Ciarletta, Daniel; Passchier, Sandra", "repository": "USAP-DC", "science_program": null, "title": "Particle-size distributions of Eocene sediment from ODP Site 1166, Prydz Bay", "url": "https://www.usap-dc.org/view/dataset/601455"}, {"dataset_uid": "000192", "doi": "", "keywords": null, "people": null, "repository": "NCEI", "science_program": null, "title": "Antarctic Geochemistry Data and Mean Annual Temperature Reconstruction through the Eocene-Oligocene Transition", "url": "https://www.ncdc.noaa.gov/paleo-search/study/21770"}], "date_created": "Tue, 25 Apr 2017 00:00:00 GMT", "description": "Intellectual Merit: This project will investigate glacial advance and retreat of the East Antarctic Ice Sheet through the Eocene-Oligocene transition, a major episode of ice growth. In Prydz Bay, East Antarctica, a 130-170 m thick Eocene-Oligocene transition interval of glaciomarine sediments was cored in drillholes of the Ocean Drilling Program at Sites 739, 742 and 1166. Correlations between the Prydz Bay drillholes have recently been made through well-log and multichannel seismic interpretations. Recent drilling on the Wilkes Land margin of East Antarctica recovered earliest Oligocene sediments overlying a major regional unconformity in two drillholes. The PI will study the lithostratigraphy and weathering history of cores in the five drillholes, to establish a unique Eocene-Oligocene transition record within Antarctic continental margin sediments of glacial advance and retreat cycles, the onset of physical weathering, and glacio-isostasy and self-gravitation processes with implications for the margin architecture, sediment routing, and off-shore sediment dispersal. Cores from the five drillholes will be re-examined through detailed core description using an updated classification scheme, so that lithofacies can be compared between drillholes. Samples will be collected for detailed laser particle size and bulk major element geochemistry via ICP-AES to determine the degree of chemical alteration of the sediments. Phases of major ice growth will be recognized as marker beds of physically eroded sediment and will be correlated to isotopic records documenting Antarctic ice growth offshore in the Southern Ocean. Broader impacts: This project will benefit a large minority undergraduate student population through the availability of up to two paid laboratory internships, a classroom exercise, and the availability of research equipment supported by this award. The project also allows support and training of a graduate student.", "east": 79.0, "geometry": "POINT(72.5 -69)", "instruments": null, "is_usap_dc": true, "keywords": "ICE SHEETS; Not provided; Prydz Bay; SEDIMENTS", "locations": "Prydz Bay", "north": -68.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Passchier, Sandra", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "NCEI; Publication; USAP-DC", "science_programs": null, "south": -70.0, "title": "The Stratigraphic Expression of the Onset of Glaciation in Eocene-Oligocene Successions on the Antarctic Continental Margin", "uid": "p0000309", "west": 66.0}, {"awards": "1245659 Petrenko, Vasilii; 1246148 Severinghaus, Jeffrey; 1245821 Brook, Edward J.", "bounds_geometry": "POINT(162.167 -77.733)", "dataset_titles": "Gas and Dust Measurements for Taylor Glacier and Taylor Dome Ice Cores; Last Interglacial Mean Ocean Temperature; Mean Ocean Temperature in Marine Isotope Stage 4; Measurements of 14CH4 and 14CO in ice from Taylor Glacier: Last Deglaciation; N2O Concentration and Isotope Data for 74-59 ka from Taylor Glacier, Antarctica; Taylor Glacier CO2 Isotope Data 74-59 kyr; Taylor Glacier Noble Gases - Younger Dryas; The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "datasets": [{"dataset_uid": "601176", "doi": "10.15784/601176", "keywords": "Antarctica; CO2; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Methane; Noble Gas; Noble Gas Isotopes; Snow/ice; Snow/Ice; Taylor Glacier; Younger Dryas", "people": "Shackleton, Sarah", "repository": "USAP-DC", "science_program": "Taylor Dome Ice Core", "title": "Taylor Glacier Noble Gases - Younger Dryas", "url": "https://www.usap-dc.org/view/dataset/601176"}, {"dataset_uid": "601198", "doi": "10.15784/601198", "keywords": "Antarctica; Blue Ice; Chemistry:ice; Chemistry:Ice; CO2; Dust; Gas; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Mass Spectrometer; Methane; Nitrogen Isotopes; Oxygen Isotope; Paleoclimate; Snow/ice; Snow/Ice; Taylor Dome; Taylor Dome Ice Core", "people": "Dyonisius, Michael; Menking, James; Brook, Edward J.; Marcott, Shaun; Barker, Stephen; Shackleton, Sarah; Petrenko, Vasilii; McConnell, Joseph; Rhodes, Rachel; Bauska, Thomas; Severinghaus, Jeffrey P.; Baggenstos, Daniel", "repository": "USAP-DC", "science_program": null, "title": "Gas and Dust Measurements for Taylor Glacier and Taylor Dome Ice Cores", "url": "https://www.usap-dc.org/view/dataset/601198"}, {"dataset_uid": "600163", "doi": "10.15784/600163", "keywords": "Antarctica; Atmosphere; Geochemistry; Ice Core Records; Isotope; Paleoclimate; Taylor Glacier; Transantarctic Mountains", "people": "Brook, Edward J.", "repository": "USAP-DC", "science_program": null, "title": "The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "url": "https://www.usap-dc.org/view/dataset/600163"}, {"dataset_uid": "601398", "doi": "10.15784/601398", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Data; Ice Core Gas Records; Ice Core Records; Marine Isotope Stage 4; MIS 4; Nitrous Oxide; Pleistocene; Taylor Dome Ice Core; Taylor Glacier", "people": "Severinghaus, Jeffrey P.; Menking, James; Brook, Edward J.; Schilt, Adrian; Shackleton, Sarah; Dyonisius, Michael; Petrenko, Vasilii", "repository": "USAP-DC", "science_program": "Taylor Dome Ice Core", "title": "N2O Concentration and Isotope Data for 74-59 ka from Taylor Glacier, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601398"}, {"dataset_uid": "601218", "doi": "10.15784/601218", "keywords": "Antarctica; Carbon-14; Carbon Dioxide; Chemistry:ice; Chemistry:Ice; CO2; Dome C Ice Core; Epica; Epica Dome C; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Chemistry; Ice Core Data; Ice Core Gas Records; Ice Core Records; Isotope Data; Last Interglacial; Mass Spectrometer; Mass Spectrometry; Methane; Oxygen; Oxygen Isotope; Paleotemperature; Pleistocene; Snow/ice; Snow/Ice; Taylor Dome Ice Core; Taylor Glacier", "people": "Shackleton, Sarah", "repository": "USAP-DC", "science_program": "Dome C Ice Core", "title": "Last Interglacial Mean Ocean Temperature", "url": "https://www.usap-dc.org/view/dataset/601218"}, {"dataset_uid": "601218", "doi": "10.15784/601218", "keywords": "Antarctica; Carbon-14; Carbon Dioxide; Chemistry:ice; Chemistry:Ice; CO2; Dome C Ice Core; Epica; Epica Dome C; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Chemistry; Ice Core Data; Ice Core Gas Records; Ice Core Records; Isotope Data; Last Interglacial; Mass Spectrometer; Mass Spectrometry; Methane; Oxygen; Oxygen Isotope; Paleotemperature; Pleistocene; Snow/ice; Snow/Ice; Taylor Dome Ice Core; Taylor Glacier", "people": "Shackleton, Sarah", "repository": "USAP-DC", "science_program": "Taylor Dome Ice Core", "title": "Last Interglacial Mean Ocean Temperature", "url": "https://www.usap-dc.org/view/dataset/601218"}, {"dataset_uid": "601600", "doi": "10.15784/601600", "keywords": "Antarctica; Taylor Glacier", "people": "Bauska, Thomas; Buffen, Aron; Brook, Edward J.; Shackleton, Sarah; Menking, James; Menking, Andy; Petrenko, Vasilii; Dyonisius, Michael; Severinghaus, Jeffrey P.; Barker, Stephen", "repository": "USAP-DC", "science_program": null, "title": "Taylor Glacier CO2 Isotope Data 74-59 kyr", "url": "https://www.usap-dc.org/view/dataset/601600"}, {"dataset_uid": "601260", "doi": "10.15784/601260", "keywords": "Antarctica; Carbon-14; Cosmogenic; Ice Core; Methane", "people": "Dyonisius, Michael; Petrenko, Vasilii", "repository": "USAP-DC", "science_program": "Taylor Dome Ice Core", "title": "Measurements of 14CH4 and 14CO in ice from Taylor Glacier: Last Deglaciation", "url": "https://www.usap-dc.org/view/dataset/601260"}, {"dataset_uid": "601415", "doi": "10.15784/601415", "keywords": "Antarctica; Glaciology; Ice Core Data; Ice Core Records; Paleoclimate; Paleotemperature; Taylor Glacier", "people": "Shackleton, Sarah", "repository": "USAP-DC", "science_program": null, "title": "Mean Ocean Temperature in Marine Isotope Stage 4", "url": "https://www.usap-dc.org/view/dataset/601415"}], "date_created": "Mon, 13 Jul 2015 00:00:00 GMT", "description": "1245659/Petrenko This award supports a project to use the Taylor Glacier, Antarctica, ablation zone to collect ice samples for a range of paleoenvironmental studies. A record of carbon-14 of atmospheric methane (14CH4) will be obtained for the last deglaciation and the Early Holocene, together with a supporting record of CH4 stable isotopes. In-situ cosmogenic 14C content and partitioning of 14C between different species (14CH4, C-14 carbon monoxide (14CO) and C-14 carbon dioxide (14CO2)) will be determined with unprecedented precision in ice from the surface down to ~67 m. Further age-mapping of the ablating ice stratigraphy will take place using a combination of CH4, CO2, \u0026#948;18O of oxygen gas and H2O stable isotopes. High precision, high-resolution records of CO2, \u0026#948;13C of CO2, nitrous oxide (N2O) and N2O isotopes will be obtained for the last deglaciation and intervals during the last glacial period. The potential of 14CO2 and Krypton-81 (81Kr) as absolute dating tools for glacial ice will be investigated. The intellectual merit of proposed work includes the fact that the response of natural methane sources to continuing global warming is uncertain, and available evidence is insufficient to rule out the possibility of catastrophic releases from large 14C-depleted reservoirs such as CH4 clathrates and permafrost. The proposed paleoatmospheric 14CH4 record will improve our understanding of the possible magnitude and timing of CH4 release from these reservoirs during a large climatic warming. A thorough understanding of in-situ cosmogenic 14C in glacial ice (production rates by different mechanisms and partitioning between species) is currently lacking. Such an understanding will likely enable the use of in-situ 14CO in ice at accumulation sites as a reliable, uncomplicated tracer of the past cosmic ray flux and possibly past solar activity, as well as the use of 14CO2 at both ice accumulation and ice ablation sites as an absolute dating tool. Significant gaps remain in our understanding of the natural carbon cycle, as well as in its responses to global climate change. The proposed high-resolution, high-precision records of \u0026#948;13C of CO2 would provide new information on carbon cycle changes both during times of rising CO2 in a warming climate and falling CO2 in a cooling climate. N2O is an important greenhouse gas that increased by ~30% during the last deglaciation. The causes of this increase are still largely uncertain, and the proposed high-precision record of N2O concentration and isotopes would provide further insights into N2O source changes in a warming world. The broader impacts of proposed work include an improvement in our understanding of the response of these greenhouse gas budgets to global warming and inform societally important model projections of future climate change. The continued age-mapping of Taylor Glacier ablation ice will add value to this high-quality, easily accessible archive of natural environmental variability. Establishing 14CO as a robust new tracer for past cosmic ray flux would inform paleoclimate studies and constitute a valuable contribution to the study of the societally important issue of climate change. The proposed work will contribute to the development of new laboratory and field analytical systems. The data from the study will be made available to the scientific community and the broad public through the NSIDC and NOAA Paleoclimatology data centers. 1 graduate student each will be trained at UR, OSU and SIO, and the work will contribute to the training of a postdoc at OSU. 3 UR undergraduates will be involved in fieldwork and research. The work will support a new, junior UR faculty member, Petrenko. All PIs have a strong history of and commitment to scientific outreach in the forms of media interviews, participation in filming of field projects, as well as speaking to schools and the public about their research, and will continue these activities as part of the proposed work. This award has field work in Antarctica.", "east": 162.167, "geometry": "POINT(162.167 -77.733)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS; NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "Not provided; USAP-DC; FIELD INVESTIGATION; Stratigraphy; FIELD SURVEYS; Antarctica; Paleoenvironment; Methane; Ice Core; Carbon Dioxide; FIXED OBSERVATION STATIONS; Stable Isotopes; Ablation Zone; Taylor Glacier; Nitrous Oxide; USA/NSF; LABORATORY; AMD; Cosmogenic; Amd/Us", "locations": "Taylor Glacier; Antarctica", "north": -77.733, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Petrenko, Vasilii; Brook, Edward J.; Severinghaus, Jeffrey P.; PETRENKO, VASILLI", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e FIXED OBSERVATION STATIONS; Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Taylor Dome Ice Core", "south": -77.733, "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "uid": "p0000283", "west": 162.167}, {"awards": "0944517 Detrich, H. William", "bounds_geometry": "POLYGON((-67.42 -61.2,-66.28 -61.2,-65.14 -61.2,-64 -61.2,-62.86 -61.2,-61.72 -61.2,-60.58 -61.2,-59.44 -61.2,-58.3 -61.2,-57.16 -61.2,-56.02 -61.2,-56.02 -61.71,-56.02 -62.22,-56.02 -62.73,-56.02 -63.24,-56.02 -63.75,-56.02 -64.26,-56.02 -64.77,-56.02 -65.28,-56.02 -65.79,-56.02 -66.3,-57.16 -66.3,-58.3 -66.3,-59.44 -66.3,-60.58 -66.3,-61.72 -66.3,-62.86 -66.3,-64 -66.3,-65.14 -66.3,-66.28 -66.3,-67.42 -66.3,-67.42 -65.79,-67.42 -65.28,-67.42 -64.77,-67.42 -64.26,-67.42 -63.75,-67.42 -63.24,-67.42 -62.73,-67.42 -62.22,-67.42 -61.71,-67.42 -61.2))", "dataset_titles": "Cruise LMG1203; Cruise LMG1205; Cruise LMG1206; GenBank KC594078, FJ914563.1, FJ914564.1, FJ914565.1, FJ896018.1, FJ896019.1, FJ896022.1, FJ896023.1, FJ896024.1, FJ896025.1, FJ896026.1", "datasets": [{"dataset_uid": "000160", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Cruise LMG1203", "url": "https://www.rvdata.us/search/cruise/LMG1203"}, {"dataset_uid": "000159", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "GenBank KC594078, FJ914563.1, FJ914564.1, FJ914565.1, FJ896018.1, FJ896019.1, FJ896022.1, FJ896023.1, FJ896024.1, FJ896025.1, FJ896026.1", "url": "http://www.ncbi.nlm.nih.gov/genbank/"}, {"dataset_uid": "000161", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Cruise LMG1205", "url": "https://www.rvdata.us/search/cruise/LMG1205"}, {"dataset_uid": "000162", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Cruise LMG1206", "url": "https://www.rvdata.us/search/cruise/LMG1206"}], "date_created": "Fri, 20 Dec 2013 00:00:00 GMT", "description": "Since the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~40-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. The biochemical and physiological challenges facing ectotherms living in the Southern Ocean include the reduction of reaction rates and metabolic fluxes and a pervasive weakening of macromolecular interactions. Yet, Southern Ocean ectotherms are now threatened by warming over periods measured in centuries or less. The proposed research seeks to understand the molecular mechanisms of cold adaptation in Antarctic marine fishes and to assess the physiological capacity of these organisms to resist or compensate for rapid oceanic warming. The P.I. will characterize two important and interacting protein systems, the tubulins that form microtubules and the chaperonin CCT (cytoplasmic chaperonin-containing TCP-1, a family of proteins that assists the folding of the tubulins). Higher-level, integrative responses to global temperature change will be analyzed by studying the thermal dependence of cleavage in Antarctic fish embryos (a microtubule-dependent process). The objectives are (1) to determine the contributions of five novel amino acid substitutions found in Antarctic fish beta-tubulins to microtubule assembly at cold temperature. (2) to compare the functional properties of CCT from testis tissues of Antarctic fishes and mammals. (3) to evaluate the effects of increased temperature on embryogenesis in Antarctic fishes. The research will introduce graduate and REU undergraduate students to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem. The proposed work also will benefit society by developing a cold-functioning chaperonin protein folding system, of great value to the biopharmaceutical and biotechnological industries for use in folding insoluble proteins.", "east": -56.02, "geometry": "POINT(-61.72 -63.75)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -61.2, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Detrich, H. William", "platforms": "Not provided", "repo": "R2R", "repositories": "NCBI GenBank; R2R", "science_programs": null, "south": -66.3, "title": "Microtubule Function, Protein Folding, and Embryogenesis in Antarctic Fishes: An Integrative Approach", "uid": "p0000664", "west": -67.42}, {"awards": "0636883 Bell, Robin", "bounds_geometry": "POLYGON((20 -75,23 -75,26 -75,29 -75,32 -75,35 -75,38 -75,41 -75,44 -75,47 -75,50 -75,50 -76.5,50 -78,50 -79.5,50 -81,50 -82.5,50 -84,50 -85.5,50 -87,50 -88.5,50 -90,47 -90,44 -90,41 -90,38 -90,35 -90,32 -90,29 -90,26 -90,23 -90,20 -90,20 -88.5,20 -87,20 -85.5,20 -84,20 -82.5,20 -81,20 -79.5,20 -78,20 -76.5,20 -75))", "dataset_titles": "Data portal at Lamont for airborne data", "datasets": [{"dataset_uid": "000111", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Data portal at Lamont for airborne data", "url": "http://wonder.ldeo.columbia.edu/wordpress/"}], "date_created": "Tue, 02 Apr 2013 00:00:00 GMT", "description": "Bell/0636883\u003cbr/\u003e\u003cbr/\u003eThis award support a project to study the role that subglacial water plays in the overall stability of major ice sheets. An estimated 22,000 km3 of water is currently stored within Antarctica\u0027s subglacial lakes. Movement of this water occurs through a complex and largely inferred drainage system in both East and West Antarctica. Geomorphic evidence for the catastrophic drainage of subglacial lakes documents repeated events. These major flood events appear to have drained the largest subglacial lakes situated in the relatively stable interior of the East Antarctic ice sheet. Emerging evidence suggests there is a close connection between significant subglacial lakes and the onset of the Recovery Ice Stream one of the largest in East Antarctica. Our preliminary analysis of the Recovery Lakes region, East Antarctica suggests a direct linkage between lakes and streaming ice flow, specifically the 800 km long Recovery Ice Stream and its tributaries. Located just upslope of the Recovery Ice Stream, the Recovery Lakes Region is composed of 3 well-defined lakes and a fourth, ambiguous, \u0027lake-like\u0027 feature. While other large lakes have a localized impact on ice surface slope, the Recovery Lakes Region lakes are coincident with an abrupt regional change in the ice sheet surface slope. Satellite imagery demonstrates that the downslope margin of this lake area contains distinct flow strips and crevasses: both indicative of increasing ice velocities. The discovery of a series of large lakes coincident with the onset of rapid ice flow in East Antarctica clearly links subglacial lakes and ice sheet dynamics for the first time. The evidence linking the onset of streaming in the Recovery Drainage Ice Stream to the series of large subglacial lakes raises the fundamental question: How can subglacial lakes trigger the onset of ice streaming? We advance two possible mechanisms: (i) Subglacial lakes can produce accelerated ice flow through the drainage of lake water beneath the ice sheet downslope of the lakes. (ii) Subglacial lakes can produce accelerated ice flow accelerated ice flow by modifying the basal thermal gradient via basal accretion over the lakes so when the ice sheet regrounds basal melting dominates. To evaluate the contribution of lake water and the changing basal thermal gradient, we propose an integrated program incorporating satellite imagery analysis, a series of reconnaissance aerogeophysical profiles over the Recovery Lake Region and the installation of continuous GPS sites over the Recovery Lakes. This analysis and new data will enable us (1) to produce a velocity field over the Recovery Lakes Region, (2) to map the ice thickness changes over the lakes due to acceleration triggered thinning, basal melting and freezing, (3) determine the depth and possible the tectonic origin of the Recovery Lakes and (4) determine the stability of these lakes over time. These basic data sets will enable us to advance our understanding of how subglacial lakes trigger the onset of streaming. The intellectual merit of this project is that it will be the first systematic analysis of ice streams triggering the onset of ice streams. This work has profound implications for the modeling of ice sheet behavior in the future, the geologic record of abrupt climate changes and the longevity of subglacial lakes. The broader impacts of the project are programs that will reach students of all ages through undergraduates involved in the research, formal presentations in teacher education programs and ongoing public outreach efforts at major science museums. Subglacial Antarctic lake environments are emerging as a premier, major frontier for exploration during the IPY 2007-2009.", "east": 50.0, "geometry": "POINT(35 -82.5)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e AEM; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e IMAGING RADARS \u003e IMAGING RADAR SYSTEMS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e ALTIMETERS \u003e LIDAR/LASER ALTIMETERS \u003e LIDAR ALTIMETERS", "is_usap_dc": false, "keywords": "DHC-6; Basal Melting; Ice Stream; Ice Thickness; Velocity; Ice Stream Stability; Basal Freezing; Antarctica; Drainage; Aerogeophysical; Subglacial Lake; Flood Event", "locations": "Antarctica", "north": -75.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Bell, Robin; Studinger, Michael S.", "platforms": "AIR-BASED PLATFORMS \u003e PROPELLER \u003e DHC-6", "repo": "PI website", "repositories": "PI website", "science_programs": null, "south": -90.0, "title": "Subglacial Lakes and the Onset of Ice Streaming: Recovery Lakes", "uid": "p0000702", "west": 20.0}, {"awards": "0631494 Priscu, John; 0631659 Morgan-Kiss, Rachael", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": "GenBank (NCBI) 18S rRNA genes: GU969060 to GU969102, rbcL genes: GU132860 to GU132939; McMurdo Dry Valleys Long-Term Ecological Research (MCM LTER) Program", "datasets": [{"dataset_uid": "000126", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "GenBank (NCBI) 18S rRNA genes: GU969060 to GU969102, rbcL genes: GU132860 to GU132939", "url": "http://www.ncbi.nlm.nih.gov/genbank/"}, {"dataset_uid": "000125", "doi": "", "keywords": null, "people": null, "repository": "LTER", "science_program": null, "title": "McMurdo Dry Valleys Long-Term Ecological Research (MCM LTER) Program", "url": "http://www.mcmlter.org/"}], "date_created": "Fri, 08 Oct 2010 00:00:00 GMT", "description": "Data collected on the permanently ice-covered lakes of the McMurdo Dry Valleys (MCM) during the late 1950\u0027s as part of the International Geophysical Year (IGY) showed that they were the only year round liquid water environments on the continent. Organisms in the lakes must possess novel physiological strategies that allow them to survive at low temperature and under extended darkness. Subsequent research has now shown that most organisms in the lakes are not just \"surviving the extremes\" but are actively feeding, growing and reproducing. However, nearly all research on the MCM lakes is restricted to the austral spring and summer when logistical support is provided. The unique aspects of physiological adaptation and metabolic function during the permanently cold and prolonged darkness of the Antarctic winter remain unknown. As part of the \"International Polar Year 2007-2008\" (IPY), the proposed research will study lakes within the Taylor Valley during the transition to polar night to test the overarching hypothesis that the onset of darkness induces a cascade of physiological changes that alters the functional role of autotrophic and heterotrophic microplankton within the lakes. This overarching theme will be addressed through an interdisciplinary study of selected biological components of the lake ecosystems using genomic and physiological tools to understand not only how individual organisms survive, but how they control ecosystem function during this seasonal transition. \u003cbr/\u003e\u003cbr/\u003eThis project is directly relevant to IPY objectives as it addresses a major identified theme (Adaptations to Life in Extreme Cold and Prolonged Darkness) with an international (UK, NZ),\u003cbr/\u003emultidisciplinary team. The research has substantial broader impacts, as it will add to the body of long-term data accumulated by the MCM LTER and MCM Microbial Observatory projects in a synergistic manner; and it will include three undergraduates, a graduate student and two young female investigators. The project is linked to a highly visible education, outreach and human diversity programs supported by the McMurdo LTER, and initiates new outreach programs, including the Passport to Knowledge program.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -60.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Morgan-Kiss, Rachael; Priscu, John; Mikucki, Jill", "platforms": "Not provided", "repo": "NCBI GenBank", "repositories": "LTER; NCBI GenBank", "science_programs": "LTER", "south": -90.0, "title": "Collaborative Research: IPY- Plankton Dynamics in the McMurdo Dry Valley Lakes During the Transition to Polar Night", "uid": "p0000525", "west": -180.0}, {"awards": "0635470 Detrich, H. William", "bounds_geometry": "POLYGON((-67.41667 -61.2,-66.27667 -61.2,-65.13667 -61.2,-63.99667 -61.2,-62.85667 -61.2,-61.71667 -61.2,-60.57667 -61.2,-59.43667 -61.2,-58.29667 -61.2,-57.15667 -61.2,-56.01667 -61.2,-56.01667 -61.71,-56.01667 -62.22,-56.01667 -62.73,-56.01667 -63.24,-56.01667 -63.75,-56.01667 -64.26,-56.01667 -64.77,-56.01667 -65.28,-56.01667 -65.79,-56.01667 -66.3,-57.15667 -66.3,-58.29667 -66.3,-59.43667 -66.3,-60.57667 -66.3,-61.71667 -66.3,-62.85667 -66.3,-63.99667 -66.3,-65.13667 -66.3,-66.27667 -66.3,-67.41667 -66.3,-67.41667 -65.79,-67.41667 -65.28,-67.41667 -64.77,-67.41667 -64.26,-67.41667 -63.75,-67.41667 -63.24,-67.41667 -62.73,-67.41667 -62.22,-67.41667 -61.71,-67.41667 -61.2))", "dataset_titles": "Expedition Data; Expedition data of LMG1003; Expedition data of LMG1004; Sequence data", "datasets": [{"dataset_uid": "000133", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "Sequence data", "url": "http://www.ncbi.nlm.nih.gov/genbank/"}, {"dataset_uid": "001509", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0806"}, {"dataset_uid": "001508", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0807"}, {"dataset_uid": "002684", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1003", "url": "https://www.rvdata.us/search/cruise/LMG1003"}, {"dataset_uid": "002685", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1004", "url": "https://www.rvdata.us/search/cruise/LMG1004"}], "date_created": "Mon, 06 Sep 2010 00:00:00 GMT", "description": "Abstract\u003cbr/\u003e\u003cbr/\u003eSince the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~38-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. Because they live at very low and stable temperatures, Antarctic fishes of the suborder Nototheniodei are particularly attractive as models for understanding the mechanisms of biomolecular cold adaptation, or the compensatory restructuring of biochemical and physiological systems to preserve biological function in cold thermal regimes. Two interrelated and potentially co-evolved systems, the tubulins that form microtubules and the chaperonin-containing TCP1 (t-complex protein-1) complex (CCT) that assists the folding of tubulins, provide an unparalleled opportunity to elucidate these mechanisms. This research will yield new and important knowledge regarding: 1) cold adaptation of microtubule assembly and of chaperonin function; and 2) the co-evolutionary origin of tubulin-binding specificity by CCT. The first objective of this proposal is to determine the contributions of five novel amino acid substitutions found in Antarctic fish beta-tubulins to microtubule assembly at cold temperature. The second objective is to establish a chaperonin folding system in vitro using CCT purified from testis tissue of Antarctic fishes and to evaluate its thermal properties and mechanism. The third objective is to evaluate, through phylogenetically controlled contrasts, the hypothesis that CCT and its tubulin substrates from Antarctic fishes have co-evolved to function at cold temperatures. The broader impacts of this proposal include introduction of graduate and REU undergraduate students of Northeastern University to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem. Because much of the research on the biogenesis and function of cold-adapted proteins will be performed in the field at Palmer Station, these students will gain invaluable experience in the practical considerations of expeditionary biological science. The research also will increase knowledge about molecular cold adaptation in one of the Earth\u0027s extreme environments, and hence is relevant to the formulation of refined hypotheses regarding potential extraterrestrial life on Mars or Europa. The cold-functioning chaperonin protein folding system will be of great value to the biopharmaceutical and biotechnological industries for use in folding insoluble proteins.", "east": -56.01667, "geometry": "POINT(-61.71667 -63.75)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e ADCP", "is_usap_dc": true, "keywords": "R/V LMG", "locations": null, "north": -61.2, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Detrich, H. William", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "NCBI GenBank", "repositories": "NCBI GenBank; R2R", "science_programs": null, "south": -66.3, "title": "Protein Folding and Function at Cold Temperature: Co-Evolution of the Chaperonin CCT and Tubulins from Antarctic Fishes", "uid": "p0000470", "west": -67.41667}, {"awards": "9317598 Asper, Vernon", "bounds_geometry": "POLYGON((-180 -43.56582,-144.00001 -43.56582,-108.00002 -43.56582,-72.00003 -43.56582,-36.00004 -43.56582,-0.000049999999987 -43.56582,35.99994 -43.56582,71.99993 -43.56582,107.99992 -43.56582,143.99991 -43.56582,179.9999 -43.56582,179.9999 -46.943299,179.9999 -50.320778,179.9999 -53.698257,179.9999 -57.075736,179.9999 -60.453215,179.9999 -63.830694,179.9999 -67.208173,179.9999 -70.585652,179.9999 -73.963131,179.9999 -77.34061,143.99991 -77.34061,107.99992 -77.34061,71.99993 -77.34061,35.99994 -77.34061,-0.000050000000016 -77.34061,-36.00004 -77.34061,-72.00003 -77.34061,-108.00002 -77.34061,-144.00001 -77.34061,-180 -77.34061,-180 -73.963131,-180 -70.585652,-180 -67.208173,-180 -63.830694,-180 -60.453215,-180 -57.075736,-180 -53.698257,-180 -50.320778,-180 -46.943299,-180 -43.56582))", "dataset_titles": "Expedition Data", "datasets": [{"dataset_uid": "002252", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9406"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "9317598 Asper The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will focus on the collection of vertical flux samples which will be analyzed for carbon, nitrogen and total mass flux and also provided to the other investigators for their specific analyses. Profiles of the abundance of large aggregates in the water column using a non- contact photographic method will be made. These data will be used to complement other particle determinations, to investigate the role of these aggregates in particle flux and to determine the mechanisms of particle export as a function of season and phytoplankton species. The end result will be a better understanding of the bloom processes and significant contributions to the data base on aggregates and export mechanisms in this environment.", "east": 179.9999, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": -43.56582, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Asper, Vernon; Smith, Walker", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -77.34061, "title": "Collaborative Research on Bloom Dynamics and Food Web Structure in the Ross Sea: Vertical Flux of Carbon and Nitrogen", "uid": "p0000646", "west": -180.0}, {"awards": "9726180 Dorman, LeRoy", "bounds_geometry": null, "dataset_titles": "Expedition data of NBP9905", "datasets": [{"dataset_uid": "002581", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP9905", "url": "https://www.rvdata.us/search/cruise/NBP9905"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "This award, provided by the Office of Polar Programs of the National Science Foundation, supports research to investigate the seismicity and tectonics of the South Shetland Arc and the Bransfield Strait. This region presents an intriguing and unique tectonic setting, with slowing of subduction, cessation of island arc volcanism, as well as the apparent onset of backarc rifting occurring within the last four million years. This project will carry out a 5-month deployment of 14 ocean bottom seismographs (OBSs) to complement and extend a deployment of 6 broadband land seismic stations that were successfully installed during early 1997. The OBSs include 2 instruments with broadband sensors, and all have flowmeters for measuring and sampling hydrothermal fluids. The OBSs will be used to examine many of the characteristics of the Shetland- Bransfield tectonic system, including: --- The existence and depth of penetration of a Shetland Slab: The existence of a downgoing Shetland slab will be determined from earthquake locations and from seismic tomography. The maximum depth of earthquake activity and the depth of the slab velocity anomaly will constrain the current configuration of the slab, and may help clarify the relationship between the subducting slab and the cessation of arc volcanism. -- Shallow Shetland trench seismicity?: No teleseismic shallow thrust faulting seismicity has been observed along the South Shetland Trench from available seismic information. Using the OBS data, the level of small earthquake activity along the shallow thrust zone will be determined and compared to other regions undergoing slow subduction of young oceanic lithosphere, such as Cascadia, which also generally shows very low levels of thrust zone seismicity. -- Mode of deformation along the Bransfield Rift: The Bransfield backarc has an active rift in the center, but there is considerable evidence for off-rift faulting. There is a long-standing controversy about whet her back-arc extension occurs along discrete rift zones, or is more diffuse geographically. This project will accurately locate small earthquakes to better determine whether Bransfield extension is discrete or diffuse. -- Identification of volcanism and hydrothermal activity: Seismic records will be used to identify the locations of active seafloor volcanism along the Bransfield rift. Flowmeters attached to the OBSs will record and sample the fluid flux out of the sediments. -- Upper mantle structure of the Bransfield - evidence for partial melting?: Other backarc basins show very slow upper mantle seismic velocities and high seismic attenuation, characteristics due to the presence of partially molten material. This project will use seismic tomography to resolve the upper mantle structure of the Bransfield backarc, allowing comparison with other backarc regions and placing constraints on the existence of partially molten material and the importance of partial melting as a mantle process in this region. Collaborative awards: OPP 9725679 and OPP 9726180", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e MSBS", "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Wiens, Douglas", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Study of the Structure and Tectonics of the South Shetland Trench and Bransfield Backarc Using Ocean Bottom Seismographs", "uid": "p0000801", "west": null}, {"awards": "0088143 Luyendyk, Bruce; 0087392 Bartek, Louis", "bounds_geometry": "POLYGON((-179.99786 -75.91667,-143.99852 -75.91667,-107.99918 -75.91667,-71.99984 -75.91667,-36.0005 -75.91667,-0.00115999999997 -75.91667,35.99818 -75.91667,71.99752 -75.91667,107.99686 -75.91667,143.9962 -75.91667,179.99554 -75.91667,179.99554 -76.183531,179.99554 -76.450392,179.99554 -76.717253,179.99554 -76.984114,179.99554 -77.250975,179.99554 -77.517836,179.99554 -77.784697,179.99554 -78.051558,179.99554 -78.318419,179.99554 -78.58528,143.9962 -78.58528,107.99686 -78.58528,71.99752 -78.58528,35.99818 -78.58528,-0.00116000000003 -78.58528,-36.0005 -78.58528,-71.99984 -78.58528,-107.99918 -78.58528,-143.99852 -78.58528,-179.99786 -78.58528,-179.99786 -78.318419,-179.99786 -78.051558,-179.99786 -77.784697,-179.99786 -77.517836,-179.99786 -77.250975,-179.99786 -76.984114,-179.99786 -76.717253,-179.99786 -76.450392,-179.99786 -76.183531,-179.99786 -75.91667))", "dataset_titles": "Expedition Data; NBP0301 data; NBP0306 data", "datasets": [{"dataset_uid": "001724", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0301"}, {"dataset_uid": "001668", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0306"}, {"dataset_uid": "000105", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "NBP0306 data", "url": "https://www.rvdata.us/search/cruise/NBP0306"}, {"dataset_uid": "000104", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "NBP0301 data", "url": "https://www.rvdata.us/search/cruise/NBP0301"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "Luyendyk et.al.: OPP 0088143\u003cbr/\u003eBartek: OPP 0087392\u003cbr/\u003eDiebold: OPP 0087983\u003cbr/\u003e\u003cbr/\u003eThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative research program in marine geology and geophysics in the southern central and eastern Ross Sea. The project will conduct sites surveys for drilling from the Ross Ice Shelf into the seafloor beneath it. Many of the outstanding problems concerning the evolution of the East and West Antarctic Ice Sheets, Antarctic climate, global sea level, and the tectonic history of the West Antarctic Rift System can be addressed by drilling into the seafloor of the Ross Sea. Climate data for Cretaceous and Early Cenozoic time are lacking for this sector of Antarctica. Climate questions include: Was there any ice in Late Cretaceous time? What was the Antarctic climate during the Paleocene-Eocene global warming? When was the Cenozoic onset of Antarctic glaciation, when did glaciers reach the coast and when did they advance out onto the margin? Was the Ross Sea shelf non-marine in Late Cretaceous time; when did it become marine? Tectonic questions include: What was the timing of the Cretaceous extension in the Ross Sea rift; where was it located? What is the basement composition and structure? Where are the time and space limits of the effects of Adare Trough spreading? Another drilling objective is to sample and date the sedimentary section bounding the mapped RSU6 unconformity in the Eastern Basin and Central Trough to resolve questions about its age and regional extent. Deep Sea Drilling Project (DSDP) Leg 28 completed sampling at four drill sites in the early 1970\u0027s but had low recovery and did not sample the Early Cenozoic. Other drilling has been restricted to the McMurdo Sound area of the western Ross Sea and results can be correlated into the Victoria Land Basin but not eastward across basement highs. Further, Early Cenozoic and Cretaceous rocks have not been sampled. A new opportunity is developing to drill from the Ross Ice Shelf. This is a successor program to the Cape Roberts Drilling Project. One overriding difficulty is the need for site surveys at drilling locations under the ice shelf. This project will overcome this impediment by conducting marine geophysical drill site surveys at the front of the Ross Ice Shelf in the Central Trough and Eastern Basin. The surveys will be conducted a kilometer or two north of the ice shelf front where recent calving events have resulted in a southerly position of the ice shelf edge. In several years the northward advance of the ice shelf will override the surveyed locations and drilling could be accomplished. Systems to be used include swath bathymetry, gravity, magnetics, chirp sonar, high resolution seismic profiling, and 48 fold seismics. Cores will be collected to obtain samples for geotechnical properties, to study sub-ice shelf modern sedimentary processes, and at locations where deeper section is exposed.\u003cbr/\u003e\u003cbr/\u003eThis survey will include long profiles and detailed grids over potential drill sites. Survey lines will be tied to existing geophysical profiles and DSDP 270. A recent event that makes this plan timely is the calving of giant iceberg B-15 (in March, 2000) and others from the ice front in the eastern Ross Sea. This new calving event and one in 1987 have exposed 16,000 square kilometers of seafloor that had been covered by ice shelf for decades and is not explored. Newly exposed territory can now be mapped by modern geophysical methods. This project will map geological structure and stratigraphy below unconformity RSU6 farther south and east, study the place of Roosevelt Island in the Ross Sea rifting history, and determine subsidence history during Late Cenozoic time (post RSU6) in the far south and east. Finally the project will observe present day sedimentary processes beneath the ice shelf in the newly exposed areas.", "east": 179.99554, "geometry": "POINT(0 -89.999)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e TURBIDITY METERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e ADCP; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e MSBS", "is_usap_dc": true, "keywords": "R/V NBP", "locations": null, "north": -75.91667, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Bartek, Louis; Luyendyk, Bruce P.", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -78.58528, "title": "Collaborative Research: Antarctic Cretaceous-Cenozoic Climate, Glaciation, and Tectonics: Site surveys for drilling from the edge of the Ross Ice Shelf", "uid": "p0000425", "west": -179.99786}, {"awards": "9317538 Nelson, David", "bounds_geometry": null, "dataset_titles": "Expedition Data; Expedition data of NBP9406", "datasets": [{"dataset_uid": "002591", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP9406", "url": "https://www.rvdata.us/search/cruise/NBP9406"}, {"dataset_uid": "002252", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9406"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "9317538 Nelson The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will test the closely related hypotheses that: (1) phytoplankton growth is controlled primarily by the relationship between solar irradiance and mixed-layer depth throughout the spring (2) diatom growth rates are much higher in spring than at any other time of year, in response to the more favorable irradiance/mixing relationships, and (3) persistence of diatom blooms in summer results from the diatoms\u0027 ability to outcompete other groups under the light-limited conditions that develop in turbid, high-biomass waters. These hypotheses will be tested by (1) obtaining the first reliable estimates of the Sverdrup \"critical depth\" in the Antarctic so that the changing relationship between the critical depth and the mixed- layer depth in spring can be defined, and (2) estimating diatom growth rates and the gross and net production attributable to diatoms throughout the spring. The results will provide information critical to an understanding of phytoplankton bloom dynamics in the Ross Sea.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Smith, Walker", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Collaborative Research: Bloom Dynamics and Food-Web Structure in the Ross Sea: The Irradiance/Mixing Regime and Diatom Growith in Spring", "uid": "p0000810", "west": null}, {"awards": "9316035 Gowing, Marcia", "bounds_geometry": null, "dataset_titles": "Expedition Data; Expedition data of NBP9406", "datasets": [{"dataset_uid": "002592", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP9406", "url": "https://www.rvdata.us/search/cruise/NBP9406"}, {"dataset_uid": "002252", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9406"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. The focus of this proposal is the role of microzooplankton in controlling the production and fate of carbon during the two types of blooms. Objectives are: 1) to determine biomass, abundance, size and selected species composition of primary producer assemblages, 2) to determine similar features of nano- and microplanktonic heterotrophic assemblages, 3) to measure total community grazing on heterotrophic bacteria and phytoplankton, 4) to examine which grazers are the major herbivores and bacterivores, and 5) to measure the contribution of microzooplankton and mesozooplankton egesta, sinking of algal cells and colonies, and sinking of protozoan assemblages associated with detritus to the total carbon flux from the euphotic zone through 250 m depth. Water samples for abundance and biomass determinations will be taken and samples will be examined with epifluorescence microscopy. Grazing rates will be measured using the dilution grazing technique and the dual-isotope radiolabeling single cell method. Carbon fluxes will be determined on sinking material collected with particle interceptor traps at the base of the euphotic zone and two deeper depths, using microscopical analysis . An understanding of these processes and other fundamental processes studied by collaborating investigators will contribute to the understanding of the role of the Southern Ocean in present, past and predicted future sequestration of carbon, as well as in other global elemental cycles.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Walker", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Collaborative Research: Bloom Dynamics and Food Web Structure in the Ross Sea: Role of Microzooplankton in Controlling Production", "uid": "p0000811", "west": null}, {"awards": "9317587 Smith, Walker", "bounds_geometry": null, "dataset_titles": "Expedition Data; Expedition data of NBP9406", "datasets": [{"dataset_uid": "002252", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9406"}, {"dataset_uid": "002582", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP9406", "url": "https://www.rvdata.us/search/cruise/NBP9406"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will conduct a set of process-oriented experiments designed to elucidate the controls of phytoplankton productivity, growth and accumulation as well as the mechanisms which control bacterial abundance and productivity in Antarctic waters. Specifically, the relative photosynthetic and nutrient (nitrate, ammonium) characteristics of diatom- vs. Phaeocystis- dominated assemblages will be examined to test if Phaeocystis simply grows faster under spring conditions in the Ross Sea. Phytoplankton and bacterial biomass, productivity and their interactions will be measured to elucidate the complex physical-chemical-biological interactions which occur. Substantial understanding of the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions will result from this research. Finally, because the Antarctic is the ocean\u0027s largest high-nutrient, low biomass system, and hence has the greatest potential for sequestering carbon dioxide, knowledge of the dynamics of the Ross Sea phytoplankton will also increase our understanding of the carbo n cycle of the Southern Ocean.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Walker", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Collaborative Research: Bloom Dynamics and Food Web Structure in the Ross Sea: Primary Productivity, New Production and Bacterial Growth", "uid": "p0000802", "west": null}, {"awards": "0538594 Ponganis, Paul", "bounds_geometry": "POLYGON((165.983 -77.683,166.0164 -77.683,166.0498 -77.683,166.0832 -77.683,166.1166 -77.683,166.15 -77.683,166.1834 -77.683,166.2168 -77.683,166.2502 -77.683,166.2836 -77.683,166.317 -77.683,166.317 -77.6897,166.317 -77.6964,166.317 -77.7031,166.317 -77.7098,166.317 -77.7165,166.317 -77.7232,166.317 -77.7299,166.317 -77.7366,166.317 -77.7433,166.317 -77.75,166.2836 -77.75,166.2502 -77.75,166.2168 -77.75,166.1834 -77.75,166.15 -77.75,166.1166 -77.75,166.0832 -77.75,166.0498 -77.75,166.0164 -77.75,165.983 -77.75,165.983 -77.7433,165.983 -77.7366,165.983 -77.7299,165.983 -77.7232,165.983 -77.7165,165.983 -77.7098,165.983 -77.7031,165.983 -77.6964,165.983 -77.6897,165.983 -77.683))", "dataset_titles": "The Aerobic Dive Limit: Oxygen Transport and Depletion in Emperor Penguins", "datasets": [{"dataset_uid": "600057", "doi": "10.15784/600057", "keywords": "Antarctica; Biota; Oceans; Penguin; Southern Ocean", "people": "Ponganis, Paul", "repository": "USAP-DC", "science_program": null, "title": "The Aerobic Dive Limit: Oxygen Transport and Depletion in Emperor Penguins", "url": "https://www.usap-dc.org/view/dataset/600057"}], "date_created": "Sun, 20 Dec 2009 00:00:00 GMT", "description": "The research will examine blood and muscle oxygen store depletion in relation to the documented aerobic dive limit (ADL, onset of post-dive blood lactate accumulation) in diving of emperor penguins. The intellectual merits of this proposal involve its evaluation of the physiological basis of the ADL concept. The ADL is probably the most commonly-used, but rarely measured, factor to interpret and model the behavior and foraging ecology of diving animals. Based on prior studies, and on recent investigations of respiratory and blood oxygen depletion during dives of emperor penguins, it is hypothesized that the ADL is a result of the depletion of myoglobin (Mb)-bound oxygen and increased glycolysis in the primary locomotory muscles. This project will accurately define the physiological mechanisms underlying the ADL through 1) evaluation of the rate and magnitude of muscle oxygen depletion during dives in relation to the previously measured ADL, 2) characterization of the hemoglobin-oxygen dissociation curve in blood of emperor penguins and comparison of that curve to those of other diving and non-diving species, 3) application of the emperor hemoglogin-oxygen dissociation curve to previously collected oxygen and hemoglobin data in order to estimate the rate and magnitude of blood oxygen depletion during dives, and 4) measurement of muscle phosphoocreatine and glycogen concentrations in order to estimate their potential contributions to muscle energy metabolism during diving. The project also continues the census and monitoring of the emperor colonies in the Ross Sea, which is especially important in light of both fisheries activity and the movement of iceberg B15-A. Broader impacts of the project include: 1) technological development of microprocessor-based, \"backpack\" near-infrared spectrophotometer, which will be applicable not only to other species, but also to other fields (i.e., exercise physiology), 2) collaboration with the Department of Anesthesia at the U.S. Naval Hospital in San Diego in the training of anesthesia residents in research techniques, 3) the training and thesis research of two graduate students in these techniques and in Antarctic field research, and 4) a better understanding of the ADL concept and its use in the fields of diving behavior and physiology. In addition the annual census of emperor penguin colonies in the Ross Sea, in conjunction with the continued evaluation of previously developed remote cameras to monitor colony status, will form the basis of a new educational web site, and allow development of an educational outreach program to school children through SeaWorld of San Diego.", "east": 166.317, "geometry": "POINT(166.15 -77.7165)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -77.683, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Ponganis, Paul", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.75, "title": "The Aerobic Dive Limit: Oxygen Transport and Depletion in Emperor Penguins", "uid": "p0000535", "west": 165.983}, {"awards": "0636269 Harpp, Karen", "bounds_geometry": "POLYGON((161.55 -77.50314,161.5883 -77.50314,161.6266 -77.50314,161.66490000000002 -77.50314,161.7032 -77.50314,161.7415 -77.50314,161.7798 -77.50314,161.8181 -77.50314,161.8564 -77.50314,161.8947 -77.50314,161.933 -77.50314,161.933 -77.507124,161.933 -77.51110800000001,161.933 -77.515092,161.933 -77.519076,161.933 -77.52306,161.933 -77.527044,161.933 -77.531028,161.933 -77.535012,161.933 -77.538996,161.933 -77.54298,161.8947 -77.54298,161.8564 -77.54298,161.8181 -77.54298,161.7798 -77.54298,161.7415 -77.54298,161.7032 -77.54298,161.66490000000002 -77.54298,161.6266 -77.54298,161.5883 -77.54298,161.55 -77.54298,161.55 -77.538996,161.55 -77.535012,161.55 -77.531028,161.55 -77.527044,161.55 -77.52306,161.55 -77.519076,161.55 -77.515092,161.55 -77.51110800000001,161.55 -77.507124,161.55 -77.50314))", "dataset_titles": null, "datasets": null, "date_created": "Wed, 03 Jun 2009 00:00:00 GMT", "description": "This project is a field and laboratory based investigation of the Vanda dike swarm in the Dry Valleys of Antarctica. These dikes crosscut Cambro-Ordovician granitoid plutons produced during the Ross Orogeny, and mark the transition between the cessation of subduction and the onset of extensional magmatism. Many dying convergent plate margins convert to extensional magmatism, and the Dry Valleys provide a magnificent opportunity to examine the shallow roots of a plate that experienced this transition. Because of their exceptional exposure, bimodal felsic and mafic compositions, and complex field relations, the Vanda dikes have the potential to reveal insights into this important phase of Antarctic tectonic history. \u003cbr/\u003eThe broader impacts include collaboration between a primarily undergraduate and two research institutions, and support for undergraduate participation in an exciting, field-based research project.", "east": 161.933, "geometry": "POINT(161.7415 -77.52306)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -77.50314, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Harpp, Karen", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -77.54298, "title": "Collaborative Research, RUI: The Transition from Subduction to Extensional Magmatism in the Dry Valleys of Antarctica", "uid": "p0000546", "west": 161.55}, {"awards": "0338279 Siddoway, Christine", "bounds_geometry": "POLYGON((-157 -75,-155.3 -75,-153.6 -75,-151.9 -75,-150.2 -75,-148.5 -75,-146.8 -75,-145.1 -75,-143.4 -75,-141.7 -75,-140 -75,-140 -75.3,-140 -75.6,-140 -75.9,-140 -76.2,-140 -76.5,-140 -76.8,-140 -77.1,-140 -77.4,-140 -77.7,-140 -78,-141.7 -78,-143.4 -78,-145.1 -78,-146.8 -78,-148.5 -78,-150.2 -78,-151.9 -78,-153.6 -78,-155.3 -78,-157 -78,-157 -77.7,-157 -77.4,-157 -77.1,-157 -76.8,-157 -76.5,-157 -76.2,-157 -75.9,-157 -75.6,-157 -75.3,-157 -75))", "dataset_titles": "Bedrock sample data, Ford Ranges region (Marie Byrd Land)", "datasets": [{"dataset_uid": "601829", "doi": "10.15784/601829", "keywords": "Antarctica; Cryosphere; Gondwana; Marie Byrd Land; Migmatite", "people": "Siddoway, Christine", "repository": "USAP-DC", "science_program": null, "title": "Bedrock sample data, Ford Ranges region (Marie Byrd Land)", "url": "https://www.usap-dc.org/view/dataset/601829"}], "date_created": "Wed, 09 Jul 2008 00:00:00 GMT", "description": "This project will study migmatite domes found in the Fosdick Mountains of the Ford Ranges, western Marie Byrd Land, Antarctica. This area offers unique, three-dimensional exposures that may offer new insight into dome formation, which is a fundamental process of mountain building. These domes are derived from sedimentary and plutonic protoliths that are complexly interfolded at decimeter to kilometer scales. Preliminary findings from geobarometry and U-Pb monazite dating of anatexite suggest that peak metamorphism was underway at 105 Ma at crustal depths of ~25 km, followed by decompression as the Fosdick dome was emplaced to 16-17 km, or possibly as low as 8.5 km, in the crust by 99 Ma. Near-isothermal conditions were maintained during ascent, favorable for producing substantial volumes of melt through biotite-dehydration melting. This dome has been interpreted as a product of extensional exhumation. This is a viable interpretation from the regional standpoint, because the dome was emplaced in mid-Cretaceous time during the rapid onset of divergent tectonics along the proto- Pacific margin of Gondwana. However, the complex internal structures of the Fosdick Mountains have yet to be considered and may be more consistent with alternative intepretations such as upward extrusion within a contractional setting or lateral flow within a transcurrent attachment zone. This proposal is for detailed structural analysis, paired with geothermobarometry and geochronology, to determine the flow behavior and structural style that produced the internal architecture of the Fosdick dome. The results will improve our general understanding of the role of gneiss domes in transferring material and heat during mountain-building, and will characterize the behavior of the middle crust during a time of rapid transition from divergent to convergent tectonics along the active margin of Gondwana. In terms of broader impacts, this work will train undergraduate and graduate students, and involve them as collaborators in the development of curricular materials. It will also foster mentoring relationships between graduate and undergraduate students.", "east": -140.0, "geometry": "POINT(-148.5 -76.5)", "instruments": null, "is_usap_dc": false, "keywords": "Transcurrent Faults; Geochronology; Tectonic; Detachment Faults; Structural Geology; Not provided; Gneiss Dome; Migmatite", "locations": null, "north": -75.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Siddoway, Christine; Teyssier, Christian", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Gneiss Dome architecture: Investigation of Form and Process in the Fosdick Mountains, W. Antarctica", "uid": "p0000744", "west": -157.0}, {"awards": "0229638 Ponganis, Paul", "bounds_geometry": "POLYGON((163 -77,163.4 -77,163.8 -77,164.2 -77,164.6 -77,165 -77,165.4 -77,165.8 -77,166.2 -77,166.6 -77,167 -77,167 -77.1,167 -77.2,167 -77.3,167 -77.4,167 -77.5,167 -77.6,167 -77.7,167 -77.8,167 -77.9,167 -78,166.6 -78,166.2 -78,165.8 -78,165.4 -78,165 -78,164.6 -78,164.2 -78,163.8 -78,163.4 -78,163 -78,163 -77.9,163 -77.8,163 -77.7,163 -77.6,163 -77.5,163 -77.4,163 -77.3,163 -77.2,163 -77.1,163 -77))", "dataset_titles": "Diving Physiology and Behavior of Emperor Penguins", "datasets": [{"dataset_uid": "600031", "doi": "10.15784/600031", "keywords": "Antarctica; Biota; Oceans; Penguin; Southern Ocean", "people": "Ponganis, Paul", "repository": "USAP-DC", "science_program": null, "title": "Diving Physiology and Behavior of Emperor Penguins", "url": "https://www.usap-dc.org/view/dataset/600031"}], "date_created": "Mon, 31 Mar 2008 00:00:00 GMT", "description": "The emperor penguin, Aptenodytes forsteri, is the premier avian diver and a top predator in the Antarctic ecosystem. The routine occurrence of 500-m diver during foraging trips to sea is both a physiological and behavior enigma. The objectives of this project address how and why emperors dive as deep and long as they do. The project examines four major topics in the diving biology of emperor penguins: pressure tolerance, oxygen store management, end-organ tolerance of diving hypoxemia/ischemia, and deep-dive foraging behavior. These subjects are relevant to the role of the emperor as a top predator in the Antarctic ecosystem, and to critical concepts in diving physiology, including decompression sickness, nitrogen narcosis, shallow water blackout, hypoxemic tolerance, and extension of aerobic dive time. The following hypotheses will be tested: 1) Prevention of nitrogen narcosis and decompression sickness in emperor penguins is achieved by inhibition of pulmonary gas exchange at depth. 2) Shallow water black out does not occur because of greater cerebral hypoxemic tolerance, and, in deep dives, because of resumption of pulmonary gas exchange during final ascent. 3) The rate of depletion of the blood oxygen store is a function of depth of dive and heart rate. 4) The aerobic dive limit (ADL) reflects the onset of lactate accumulation in locomotory muscle, not total depletion of all oxygen stores. 5) Elevation of tissue antioxidant capacity and free-radical scavenging enzyme activities protect against the routine ischemia/reperfusion which occur during diving. 6) During deep dives, the Antarctic silverfish, Pleuorogramma antarcticum, is the primary prey item for emperors. \u003cbr/\u003e\u003cbr/\u003eIn addition to evaluation of the hypotheses below, the project has broader impacts in several areas such as partnership with foreign and national institutes and organizations (e.g., the National Institute of Polar Research of Japan, Centro de Investigacioines del Noroeste of Mexico, National Geographic, the University of Texas Southwestern Medical Center, and Sea World). Participation in National Geographic television documentaries will provide unique educational opportunities for the general public; development of state-of-the-art technology (e.g., blood oxygen electrode recorders, blood samplers, and miniaturized digital cameras) will lay the groundwork for future research by this group and others; and the effects of the B15 iceberg on breeding success of emperor penguins will continue to be evaluated with population censuses during planned fieldwork at several Ross Sea emperor penguin colonies.", "east": 167.0, "geometry": "POINT(165 -77.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -77.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Ponganis, Paul", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Diving Physiology and Behavior of Emperor Penguins", "uid": "p0000239", "west": 163.0}, {"awards": "9909436 Farley, Kenneth", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Wed, 11 Jul 2007 00:00:00 GMT", "description": "9909436 Farley This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports an investigation of the uplift history of the Dry Valleys segment of the Transantarctic Mountains. The overall goal is to further constrain the exhumation history of the Transantarctic Mountains by using the newly developed apatite (U-Th)/He dating method on samples collected in vertical profiles. This approach, combined with existing apatite fission track information will constrain the rate and patterns of exhumation across the Transantarctic Mountains since their inception as a rift-flank uplift in the early Cenozoic. This project will complement other projects and build on previous interpretations of the exhumation and tectonic history determined using apatite fission track thermochronology. It will bridge the gap between information on erosion rates determined from fission track thermochronology and from cosmogenic surface exposure dating and integrate the exhumation history of the mountains with their landscape evolution. As such, the results from this project will address an outstanding problem in Antarctic science; namely the stability of the East Antarctic Ice Sheet, and the timing of the transition from a \"warm\" dynamic ice sheet to a cold polar ice sheet. Highly relevant to this issue is the landscape evolution of the Transantarctic Mountains because many diverse lines of evidence for the rate of landscape evolution have been used to argue for a dynamic ice sheet up until either the Pliocene (the \"dynamic\" ice sheet model) or the middle Miocene (the \"stable\" ice sheet model). Understanding the past stability or dynamic fluctuations of the East Antarctic ice sheet with respect to the climate record is, of course, important for understanding how the present ice sheet may respond to global warming. The specific objective of this project is to determine apatite (U-Th)/He age versus elevation trends for a number of vertical profiles from locations within the Transantarctic Mountain front and across the structural grain of the range. Fission track data already exist for all of these profiles, with apatite fission track ages ranging from 150-30 Ma. The greater precision of the (U-Th)/He technique and the fact it records information at lower temperatures (closure temperature of ~70 degrees Celsius; limits of 40-85 degrees Celsius for the He partial retention zone) will allow examination of the exhumation history of the TAM in more detail from ca 130 Ma to ~20 Ma. Another facet is to examine areas where Cretaceous exhumation is recorded and areas where the fission track profiles indicate periods of thermal and tectonic stability and minimal erosion throughout the Cretaceous. The variation of timing of the onset of more rapid exhumation accompanying uplift and formation of the Transantarctic Mountains in the early Cenozoic will also be examined.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Farley, Kenneth", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "Collaborative Research: Exhumation of the Transantarctic Mountains: Constraints from (U-Th)/He Dating of Apatites", "uid": "p0000281", "west": null}, {"awards": "9725882 Raymond, Charles", "bounds_geometry": "POLYGON((-141.6722 -80.1678,-141.34195 -80.1678,-141.0117 -80.1678,-140.68145 -80.1678,-140.3512 -80.1678,-140.02095 -80.1678,-139.6907 -80.1678,-139.36045 -80.1678,-139.0302 -80.1678,-138.69995 -80.1678,-138.3697 -80.1678,-138.3697 -80.4863,-138.3697 -80.8048,-138.3697 -81.1233,-138.3697 -81.4418,-138.3697 -81.7603,-138.3697 -82.0788,-138.3697 -82.3973,-138.3697 -82.7158,-138.3697 -83.0343,-138.3697 -83.3528,-138.69995 -83.3528,-139.0302 -83.3528,-139.36045 -83.3528,-139.6907 -83.3528,-140.02095 -83.3528,-140.3512 -83.3528,-140.68145 -83.3528,-141.0117 -83.3528,-141.34195 -83.3528,-141.6722 -83.3528,-141.6722 -83.0343,-141.6722 -82.7158,-141.6722 -82.3973,-141.6722 -82.0788,-141.6722 -81.7603,-141.6722 -81.4418,-141.6722 -81.1233,-141.6722 -80.8048,-141.6722 -80.4863,-141.6722 -80.1678))", "dataset_titles": "Radar Investigations of Antarctic Ice Stream Margins, Siple Dome, 1998", "datasets": [{"dataset_uid": "609303", "doi": "10.7265/N52B8VZP", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPR; Radar; Siple Dome", "people": "Raymond, Charles; Nereson, Nadine A.", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Radar Investigations of Antarctic Ice Stream Margins, Siple Dome, 1998", "url": "https://www.usap-dc.org/view/dataset/609303"}], "date_created": "Fri, 06 Jul 2007 00:00:00 GMT", "description": "9725882 Raymond This award is for support for a program of surface-based radio echo sounding to examine the geometry of the internal layering and the presence or absence of thawed zones outside the margins of active Ice Streams B and E and across the flow band feeding Ice Stream D. Melting in the marginal shear zone and/or on the bed outside an ice stream relates to the amount of support of the ice stream from the sides compared to the bed and the conditions that limit expansion of its width. Radar observations will be extended over the crest of adjacent inter-ice-stream ridges (B/C and D/E) and areas next to the flow band in the onset of D. The purpose is to examine internal layering indicative of the histories of these areas adjacent to ice streams and to determine whether ice streams have expanded into these presently stable areas in the past. These goals concerning the physical controls and history of ice stream width relate to how the discharge of ice streams has changed in the past and could change in the future to affect sea level.", "east": -138.3697, "geometry": "POINT(-140.02095 -81.7603)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS", "is_usap_dc": true, "keywords": "Ice Stream; Antarctica; Bed Geometry; GROUND-BASED OBSERVATIONS; Internal Layering; Internal Layer Geometry; Siple Dome; Shabtaie Ridge; Not provided; Engelhardt Ridge; Ice Stream Margins; Radar; Whillans Ice Stream; GPS; Bed Reflectivity; Macayeal Ice Stream; Surface Geometry", "locations": "Antarctica; Engelhardt Ridge; Macayeal Ice Stream; Shabtaie Ridge; Siple Dome; Whillans Ice Stream", "north": -80.1678, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Raymond, Charles; Nereson, Nadine A.", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; Not provided; SPACE-BASED PLATFORMS \u003e NAVIGATION SATELLITES \u003e GLOBAL POSITIONING SYSTEM (GPS) \u003e GPS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": -83.3528, "title": "Internal Stratigraphy and Basal Conditions at the Margins ofActive Ice Streams of the Siple Coast, Antarctica", "uid": "p0000626", "west": -141.6722}, {"awards": "0548918 van de Flierdt, Christina-Maria", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Thu, 07 Jun 2007 00:00:00 GMT", "description": "This Small Grant for Exploratory Research supports development of a geochemical technique to time the onset of glacial erosion from Antarctica\u0027s continental ice sheets. The technique pairs neodymium (Nd) and hafnium (Hf) isotope proxies from the authigenic (seawater-derived) ferromanganese phase precipitated in marine sediments. This technique promises to be a sensitive indicator of glacial erosion. Non-radiogenic Hf is contained in the mineral zircon, which can only be released by the abrasive grinding that accompanies glacial erosion. Previous attempts to develop this technique encountered difficulty due to the minute amounts of Hf involved and the difficulty in its extraction. The PIs have developed a new chemical protocol that should allow them to selectively extract authigenic Hf from bulk sediments. If successful, studies of the Eocene-Oligocene boundary from two drill cores the Weddell Sea and Kerguelen Plateau will be carried out. This boundary is considered the initiation point for formation of Antarctica\u0027s current ice sheets. If successful, this method will benefit scientists with interests as diverse as continental weathering, ocean circulation, Cenozoic paleoceanography and paleoclimate, and Antarctic geology. \u003cbr/\u003e\u003cbr/\u003eThe broader impacts of this work are development of a new analytical technique that may improve society\u0027s understanding of the potential for global climate change from the perspective of the deep time record.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Van De Flierdt, Christina-Maria", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "SGER: Development of the Paired Authigenic Neodymium-Hafnium Isotope Weathering Tracer From Marine Sediments in the Circum Antarctic Realm", "uid": "p0000130", "west": null}, {"awards": "0125610 Waddington, Edwin", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Mon, 30 Apr 2007 00:00:00 GMT", "description": "0125610\u003cbr/\u003eWaddington\u003cbr/\u003e\u003cbr/\u003eThis award provides three years of funding to study the transition from slow inland flow to fast ice stream flow by making use of a suite of geophysical measurements that have been made near the onset region of ice stream D in West Antarctica. These data provide a unique opportunity to develop and validate glaciological models of the controlling processes in ice stream onset zones. Important processes to quantify are motion at the bed and deformation in the ice. Previous analyses indicate that the controlling resistive forces shift from the bed to the sides during the transition from slow inland flow to fast, streaming flow. Model sensitivity analyses will be used to investigate the relative importance of feedbacks between basal processes and ice deformation in the transition from inland to ice stream flow. Model experiments will determine what factors control the location of the onset of streaming flow, and how that location might migrate when conditions at the bed, or along the flow direction, changes over time. The overall goal of this work is to improve understanding of the evolution of the WAIS drainage system. This study is a first step towards understanding the physics that govern the transition from slow inland flow to fast streaming flow.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES", "is_usap_dc": false, "keywords": "FIXED OBSERVATION STATIONS", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Price, Stephen", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e FIXED OBSERVATION STATIONS", "repositories": null, "science_programs": null, "south": null, "title": "Model Investigations of the Transition from Inland to Ice Stream Flow", "uid": "p0000759", "west": null}, {"awards": "9814816 Blankenship, Donald", "bounds_geometry": "POLYGON((-129 -80.5,-128.4 -80.5,-127.8 -80.5,-127.2 -80.5,-126.6 -80.5,-126 -80.5,-125.4 -80.5,-124.8 -80.5,-124.2 -80.5,-123.6 -80.5,-123 -80.5,-123 -80.55,-123 -80.6,-123 -80.65,-123 -80.7,-123 -80.75,-123 -80.8,-123 -80.85,-123 -80.9,-123 -80.95,-123 -81,-123.6 -81,-124.2 -81,-124.8 -81,-125.4 -81,-126 -81,-126.6 -81,-127.2 -81,-127.8 -81,-128.4 -81,-129 -81,-129 -80.95,-129 -80.9,-129 -80.85,-129 -80.8,-129 -80.75,-129 -80.7,-129 -80.65,-129 -80.6,-129 -80.55,-129 -80.5))", "dataset_titles": null, "datasets": null, "date_created": "Tue, 13 Feb 2007 00:00:00 GMT", "description": "9814816 Blankenship This award supports a four year project to develop of better understanding the ice streams of the Ross Sea Embayment (A--F) which drain the interior West Antarctic Ice Sheet (WAIS) by rapidly moving vast quantities of ice to the calving front of the Ross Ice Shelf. The project will examine the role of these ice streams as buffers between the interior ice and the floating ice shelves. The reasons for their fast flow, the factors controlling their current grounding-line-, margin-, and head-positions are crucial to any attempt at modeling the WAIS system and predicting the future of the ice sheet. For the Antarctic ice streams of the Siple Coast, the transition from no-sliding (or all internal deformation) to motion dominated by sliding is defined as the \"onset-region\". To fully understand (and adequately model) the WAIS, this onset region must be better understood. The lateral margins of the ice streams are also a transition that need better explanation. Hypotheses on controls of the location of the onset region range from the \"purely-glaciologic\" to the \"purely-geologic. Thus, to model the ice sheet accurately, the basal boundary conditions (roughness, wetness, till properties) and a good subglacial geologic map, showing the distribution, thickness, and properties of the sedimentary basins, are required. These parameters can be estimated from seismic, radar, and other geophysical methods. The transition region of ice stream D will be studied in detail with this coupled geophysical experiment. In addition, selected other locations on ice streams C \u0026 D will be made, to compare and contrast conditions with the main site on ice stream D. Site-selection for the main camp will be based on existing radar, GPS, and satellite data as well as input from the modeling community.", "east": -123.0, "geometry": "POINT(-126 -80.75)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR", "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": -80.5, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Blankenship, Donald D.", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -81.0, "title": "Collaborative Research: Characterizing the Onset of Ice Stream Flow: A Ground Geophysical Field Program", "uid": "p0000603", "west": -129.0}, {"awards": "9318121 Anandakrishnan, Sridhar", "bounds_geometry": null, "dataset_titles": "Ice Velocity Data from Ice Stream C, West Antarctica", "datasets": [{"dataset_uid": "609106", "doi": "10.7265/N5CZ3539", "keywords": "Antarctica; Geodesy; Geology/Geophysics - Other; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; GPS; WAIS", "people": "Anandakrishnan, Sridhar", "repository": "USAP-DC", "science_program": null, "title": "Ice Velocity Data from Ice Stream C, West Antarctica", "url": "https://www.usap-dc.org/view/dataset/609106"}], "date_created": "Sat, 01 Dec 2001 00:00:00 GMT", "description": "9318121 Anandakrishnan This award is for support for a three year project to test the hypothesis that a controlling parameter of fast ice-stream flow is the hydrologic state of discrete zones of high friction (\"sticky spots\") at the bed of the ice streams. Previous work has discovered an enormous difference in basal microearthquake activity between fast-flowing ice stream B and ice stream C, which stopped flowing within the last 200 years. It is hypothesized that the basal water system is lubricating the sticky spots under the fast ice stream and thus inhibiting microearthquake activity, and at the same time permitting fast ice flow. This experiment is intended to collect a continuous record of wide-bandwidth microearthquake data from a variety of sites, on the ice streams, in the transition zone, and on the inland ice. ***", "east": null, "geometry": null, "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS", "is_usap_dc": true, "keywords": "Glaciology; USAP-DC; Ice Stream; Velocity Measurements; Ice Velocity; GROUND-BASED OBSERVATIONS; Ice Sheet; West Antarctic Ice Sheet; Ice Stream C Velocities; GPS; Antarctica", "locations": "Antarctica; West Antarctic Ice Sheet", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Anandakrishnan, Sridhar", "platforms": "LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Microearthquake Monitoring of Ice Stream C, West Antarctica: A Sensor for Sticky Spots", "uid": "p0000161", "west": null}]
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Siddoway, Christine; Thomson, Stuart; Teyssier, Christian
No project link provided
in progress
No project link provided
in progress
Sediment records off the coast of Marie Byrd Land (MBL), Antarctica suggest frequent and dramatic changes in the size of the West Antarctic Ice Sheet (WAIS) over short (tens of thousands of years) and long (millions of years) time frames in the past. WAIS currently overrides much of MBL and covers the rugged and scoured bedrock landscape. The ice sheet carved narrow linear troughs that reach depths of two to three thousand meters below sea level as outlet glaciers flowed from the interior of the continent to the oceans. As a result, large volumes of fragmented continental bedrock were carried out to the seabed. The glaciers cut downward into a region of crystalline rocks (i.e. granite) whose temperature change as a function of rock depth happens to be significant. This strong geothermal gradient in the bedrock is favorable for determining when the bedrock experienced rapid exhumation or "uncovering". Analyzing the chemistry of minerals (zircon and apatite) within the eroded rocks will provide information about the rate and timing of the glacier removal of bedrock from the Antarctic continent. The research addresses the following questions: When did the land become high enough for a large ice sheet to form? What was the regional pre-glacial topography? Under what climate conditions, and at what point in the growth of an ice sheet, did glaciers begin to cut sharply into bedrock to form the narrow troughs that flow seaward? The research will lead to greater understanding of past Antarctic ice sheet fluctuations and identify precise timing of glacial incision. These results will refine ice sheet history and aid the international societal response to contemporary ice sheet change and its global consequences. The project will contribute to the training of two graduate and two undergraduate students in STEM. The objective is to clarify the onset of WAIS glacier incision and assess the evolution of Cenozoic paleo-topography. Low-temperature (T) thermochronology and Pecube 3-D thermo-kinematic modeling will be applied to date and characterize episodes of glacial erosional incision. Single-grain double- and triple-dating of zircon and apatite will reveal the detailed crustal thermal evolution of the region enabling the research team to determine the comparative topographic influences on glaciation versus bedrock uplift induced by Eocene to present tectonism/magmatism. High-T mineral thermochronometers across Marie Byrd Land (MBL) record rapid extension-related cooling at ~100 Ma from temperatures of >800 degrees C to ≤ 300 degrees C. This signature forms a reference horizon, or paleogeotherm, through which the Cenozoic landscape history using low-T thermochronometers can be explored. MBL's elevated geothermal gradient, sustained during the Cenozoic, created favorable conditions for sensitive apatite and zircon low-T thermochronometers to record bedrock cooling related to glacial incision. Students will be trained to use state-of-the-art analytical facilities in Arizona and Minnesota, expanding the geo- and thermochronologic history of MBL from bedrock samples and offshore sedimentary deposits. The temperature and time data they acquire will provide constraints on paleotopography, isostasy, and the thermal evolution of MBL that will be modeled in 3D using Pecube model simulations. Within hot crust, less incision is required to expose bedrock containing the distinct thermochronometric profile; a prediction that will be tested with inverse Pecube 3-D models of the thermal field through which bedrock and detrital samples cooled. Using results from Pecube, the ICI-Hot team will examine time-varying topography formed in response to changes in erosion rates, topographic relief, geothermal gradient and/or flexural isostatic rigidity. These effects are manifestations of dynamic processes in the WAIS, including ice sheet loading, ice volume fluctuations, relative motion upon crustal faults, and magmatism-related elevation increase across the MBL dome. The project makes use of pre-existing sample collections housed at the US Polar Rock Repository, IODP's Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
van der Veen, Cornelis; Stearns, Leigh; Paden, John
No dataset link provided
Van der Veen/1543530 The objective of this research is to gain better understanding of the West Antarctic ice flow in the transition region from grounded ice to floating ice shelves and investigate the conditions that can initiate and sustain major retreat of these glaciers. Several major Antarctic outlet glaciers and ice streams will be investigated using a suite of observational techniques and modeling tools. Glaciers include Thwaites Glacier, which has become a focal point in the discussion of West Antarctic retreat, Whillans Ice Stream as an example of the archetype ice stream, and Byrd Glacier, a major outlet glacier draining East Antarctica through the Transantarctic Mountains into the Ross Ice Shelf. This study will investigate whether the ongoing changes in these glaciers will lead to long-term mass loss (the onset of ice sheet collapse), or whether these glaciers will quickly stabilize with a new geometry. To adequately incorporate the dynamic behavior of outlet glaciers and ice streams requires inclusion of the relevant physical processes, and the development of regional models that employ a numerical grid with a horizontal grid spacing sufficiently refined to capture smaller-scale bed topographic features that may control the flow of these glaciers. This award revisits the issue of stability of marine-terminating glaciers whose grounding line is located on a retrograded bed slope. In particular, an attempt will be made to resolve the question whether observed rapid changes are the result of perturbations at the terminus or grounding line, or whether these changes reflect ice-dynamical forcing over the grounded reaches. High-resolution satellite imagery will be used to investigate ice-flow perturbations on smaller spatial scales than has been done before, to evaluate the importance of localized sites of high basal resistance on grounding-line stability. This collaborative project involves a range of modeling strategies including force-budget analysis, flow-band modeling, Full Stokes modeling for local studies, and using the Ice Sheet System Model developed at JPL for regional modeling. Broader Impacts include training two graduate students in computer simulations and ice sheet modeling algorithms. The work will also expand on a web-based interactive flowline model, so that it includes more realistic grounding line dynamics.
Ice cores are a vital source of information about past climate. Research that utilizes ice cores benefits from an undamaged ice-core record. There is often a zone within ice sheets where the ice is brittle upon extraction in a core. Brittle-ice behavior occurs when the rapid decompression of the core as it is being extracted from the ice-sheet results in extensive fracturing. Ice from this zone can compromise the undamaged record. This project seeks to improve our understanding of the mechanisms involved in brittle-ice behavior and onset, with the goal of helping to guide field-site operations, core handling preparation, and planned laboratory measurement techniques for future ice-coring projects, including the upcoming work at Hercules Dome. This project requires no field work, as it will use existing observations and existing ice cores to gain an understanding of brittle ice. This is a high-risk and timely proposal that is early-concept and exploratory in nature, making it appropriate for the EAGER solicitation. The project will support an early-career researcher and provide training for a master’s student who is a woman. And, finally, the project will develop educational and outreach materials for graduate and undergraduate courses and elementary schools. This project will examine and catalog brittle ice from several existing ice-core samples to specifically assess various ice physical properties affecting brittleness potential, including bubble size and number-density, ice fabric, grain statistics, fracture characteristics, and the location and properties of grain and subgrain boundaries. End members of this sample assessment have been identified and include Siple Dome, which exhibited major brittle behavior and damage, and South Pole ice core, which exhibited very-minor brittle behavior and almost no damage. Output datasets will include calibrated relationships for bubble number-density, mean grain and bubble sizes, subgrain prevalence and orientation, and a usable indicator for estimating brittle-ice onset and magnitude. There is an immediate applicability of results from this effort for the Hercules Dome drilling project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). An important part of understanding future climate change is predicting changes in how fast the ice in Antarctica is moving. If ice flows more quickly towards the ocean, it will have a direct impact on sea level rise. One of the things that can influence the ice flow is the type of rock below the ice coverage in Antarctica. Sedimentary basins are large regions where sedimentary rocks accumulated in the past, often under ancient seas. It has been observed that where there are sediments below the ice, the ice can flow faster. This project seeks to understand what is below the ice and how the underlying rock influences the ice flow. Is it hard, crystalline rock? Is it a sedimentary basin? What is the relationship between sediments and ice flow? The answers to these questions will be addressed by using a combination of available data and geophysical methods. Information from well-known rock-types will be used to train the computer to recognize these features by using an application of artificial intelligence known as machine learning, which will help the characterization and identification of unknown sedimentary basins beneath the ice. The results of this project will be disseminated to a broad audience by holding workshops for teacher and students to explain our findings under the ice and to introduce the machine learning technique. Open-source codes used during this project will be made available for use in higher-level classrooms as well as in further studies. To date, no comprehensive distribution of onshore and offshore sedimentary basins over Antarctica has been developed. A combination of large-scale datasets will be used to characterize known basins and identify new sedimentary basins to produce the first continent-wide mapping of sedimentary basins and provide improved basal parametrizations conditions that have the potential to support more realistic ice sheet models. Available geophysical compilations of data and the location of well-known sedimentary basins will be used to apply an ensemble machine learning algorithm. The machine learning algorithm will learn complex relationships by voting among a collection of randomized decision trees. The gravity signal related to sedimentary basins known from other (e.g. seismic) techniques will be evaluated and unknown basins from aerogravity data regression analyses will be proposed by calculating a gravity residual that reflects density inhomogeneities. The gravimetric sedimentary basins identified from the regression analyses will be compared with an independent method of identifying sedimentary distribution, the Werner deconvolution method of estimating depth to magnetic sources. The hypothesis, which is sedimentary basins are correlated to fast ice flow behavior, will be tested by comparing the location of the sedimentary basins with locations of high ice flow by using available ice velocity observations. A relationship between sedimentary basins and ice streams will be defined qualitatively and quantitatively, aiming to evaluate if there are ice streams where no sedimentary basins are reported, or sedimentary basins with no ice streams related. The findings of these project can confirm if the presence of abundant sediments is a pre-requisite for ice streaming. Analyzing previously known sedimentary basins and identifying new ones in Antarctica is central to evaluating the influence of subglacial sediments on the ice sheet flow. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
The West Antarctic Ice Sheet is the most vulnerable polar ice mass to warming and already a major contributor to global mean sea level rise. Its fate in the light of prolonged warming is a topic of major uncertainty. Accelerated sea level rise from ice mass loss in the polar regions is a major concern as a cause of increased coastal flooding affecting millions of people. This project will disclose a unique geological archive buried beneath the seafloor off the Amundsen Sea, Antarctica, which will reveal how the West Antarctic Ice Sheet behaved in a warmer climate in the past. The data and insights can be used to inform ice-sheet and ocean modeling used in coastal policy development. The project will also support the development of a competitive U.S. STEM workforce. Online class exercises for introductory geology classes will provide a gateway for qualified students into undergraduate research programs and this project will enhance the participation of women in science by funding the education of current female Ph.D. students. The project targets the long-term variability of the West Antarctic Ice Sheet over several glacial-interglacial cycles in the early Pliocene sedimentary record drilled by the International Ocean Discovery Program (IODP) Expedition 379 in the Amundsen Sea. Data collection includes 1) the sand provenance of ice-rafted debris and shelf diamictites and its sources within the Amundsen Sea and Antarctic Peninsula region; 2) sedimentary structures and sortable silt calculations from particle size records and reconstructions of current intensities and interactions; and 3) the bulk provenance of continental rise sediments compared to existing data from the Amundsen Sea shelf with investigations into downslope currents as pathways for Antarctic Bottom Water formation. The results are analyzed within a cyclostratigraphic framework of reflectance spectroscopy and colorimetry (RSC) and X-ray fluorescence scanner (XRF) data to gain insight into orbital forcing of the high-latitude processes. The early Pliocene Climatic Optimum (PCO) ~4.5-4.1 Ma spans a major warm period recognized in deep-sea stable isotope and sea-surface temperature records. This period also coincides with a global mean sea level highstand of > 20 m requiring contributions in ice mass loss from Antarctica. The following hypotheses will be tested: 1) that the West Antarctic Ice Sheet retreated from the continental shelf break through an increase in sub iceshelf melt and iceberg calving at the onset of the PCO ~4.5 Ma, and 2) that dense shelf water cascaded down through slope channels after ~4.5 Ma as the continental shelf became exposed during glacial terminations. The project will reveal for the first time how the West Antarctic Ice Sheet operated in a warmer climate state prior to the onset of the current “icehouse” period ~3.3 Ma. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Antarctica is almost entirely covered by ice, in places over two miles thick. This ice hides a landscape that is less well known than the surface of Mars and represents one of Earth's last unexplored frontiers. Ice-penetrating radar images provide a remote glimpse of this landscape including ice-buried mountains larger than the European Alps and huge fjords twice as deep as the Grand Canyon. The goal of this project is to collect sediment samples derived from these landscapes to determine when and under what conditions these features formed. Specifically, the project seeks to understand the landscape in the context of the history and dynamics of the overlying ice sheet and past mountain-building episodes. This project accomplishes this goal by analyzing sand collected during previous sea-floor drilling expeditions off the coast of Antarctica. This sand was supplied from the continent interior by ancient rivers when it was ice-free over 34 million year ago, and later by glaciers. The project will also study bedrock samples from rare ice-free parts of the Transantarctic Mountains. The primary activity is to apply multiple advanced dating techniques to single mineral grains contained within this sand and rock. Different methods and minerals yield different dates that provide insight into how Antarctica?s landscape has eroded over the many tens of millions of years during which sand was deposited offshore. The dating techniques that are being developed and enhanced for this study have broad application in many branches of geoscience research and industry. The project makes cost-effective use of pre-existing sample collections housed at NSF facilities including the US Polar Rock Repository, the Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. The project will contribute to the STEM training of two graduate and two undergraduate students, and includes collaboration among four US universities as well as international collaboration between the US and France. The project also supports outreach in the form of a two-week open workshop giving ten students the opportunity to visit the University of Arizona to conduct STEM-based analytical work and training on Antarctic-based projects. Results from both the project and workshop will be disseminated through presentations at professional meetings, peer-reviewed publications, and through public outreach and media. The main objective of this project is to reconstruct a chronology of East Antarctic subglacial landscape evolution to understand the tectonic and climatic forcing behind landscape modification, and how it has influenced past ice sheet inception and dynamics. Our approach focuses on acquiring a record of the cooling and erosion history contained in East Antarctic-derived detrital mineral grains and clasts in offshore sediments deposited both before and after the onset of Antarctic glaciation. Samples will be taken from existing drill core and marine sediment core material from offshore Wilkes Land (100°E-160°E) and the Ross Sea. Multiple geo- and thermo-chronometers will be employed to reconstruct source region cooling history including U-Pb, fission-track, and (U-Th)/He dating of zircon and apatite, and 40Ar/39Ar dating of hornblende, mica, and feldspar. This offshore record will be augmented and tested by applying the same methods to onshore bedrock samples in the Transantarctic Mountains obtained from the US Polar Rock Repository and through fieldwork. The onshore work will additionally address the debated incision history of the large glacial troughs that cut the range, now occupied by glaciers draining the East Antarctic Ice Sheet. This includes collection of samples from several age-elevation transects, apatite 4He/3He thermochronometry, and Pecube thermo-kinematic modeling. Acquiring an extensive geo- and thermo-chronologic database will also provide valuable new information on the poorly known ice-hidden geology and tectonics of subglacial East Antarctica that has implications for improving supercontinent reconstructions and understanding continental break-up.
Antarctic krill are essential in the Southern Ocean as they support vast numbers of marine mammals, seabirds and fishes, some of which feed almost exclusively on krill. Antarctic krill also constitute a target species for industrial fisheries in the Southern Ocean. The success of Antarctic krill populations is largely determined by the ability of their young to survive the long, dark winter, where food is extremely scarce. To survive the long-dark winter, young Antarctic krill must have a high-quality diet in autumn. However, warming in certain parts of Antarctica is changing the dynamics and quality of the polar food web, resulting in a shift in the type of food available to young krill in autumn. It is not yet clear how these dynamic changes are affecting the ability of krill to survive the winter. This project aims to fill an important gap in current knowledge on an understudied stage of the Antarctic krill life cycle, the 1-year old juveniles. The results derived from this work will contribute to the development of improved bioenergetic, population and ecosystem models, and will advance current scientific understanding of this critical Antarctic species. This CAREER project's core education and outreach objectives seek to enhance education and increase diversity within STEM fields. An undergraduate course will be developed that will integrate undergraduate research and writing in way that promotes authentic scientific inquiry and analysis of original research data by the students, and that enhances their communication skills. A graduate course will be developed that will promote students' skills in communicating their own research to a non-scientific audience. Graduate students will be supported through the proposed study and will gain valuable research experience. Traditionally underserved undergraduate students will be recruited to conduct independent research under the umbrella of the larger project. Throughout each field season, the research team will maintain a weekly blog that will include short videos, photographs and text highlighting the research, as well as their experiences living and working in Antarctica. The aim of the blog will be to engage the public and increase awareness and understanding of Antarctic ecosystems and the impact of warming, and of the scientific process of research and discovery. In this 5-year CAREER project, the investigator will use a combination of empirical and theoretical techniques to assess the effects of diet on 1-year old krill in autumn-winter. The research is centered on four hypotheses: (H1) autumn diet affects 1-year old krill physiology and condition at the onset of winter; (H2) autumn diet has an effect on winter physiology and condition of 1-year old krill under variable winter food conditions; (H3) the rate of change in physiology and condition of 1-year old krill from autumn to winter is dependent on autumn diet; and (H4) the winter energy budget of 1-year old krill will vary between years and will be dependent on autumn diet. Long-term feeding experiments and in situ sampling will be used to measure changes in the physiology and condition of krill in relation to their diet and feeding environment. Empirically-derived data will be used to develop theoretical models of growth rates and energy budgets to determine how diet will influence the overwinter survival of 1-year old krill. The research will be integrated with an education and outreach plan to (1) develop engaging undergraduate and graduate courses, (2) train and develop young scientists for careers in polar research, and (3) engage the public and increase their awareness and understanding. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
The waters of the Ross Sea continental shelf are among the most productive in the Southern Ocean, and may comprise a significant regional oceanic sink for atmospheric carbon dioxide. In this region, primary production can be limited by the supply of dissolved iron to surface waters during the growing season. Water-column observations, sampling and measurements are to be carried out in the late autumn-early winter time frame on the Ross Sea continental shelf and coastal polynyas (Terra Nova Bay and Ross Ice Shelf polynyas), in order to better understand what drives the biogeochemical redistribution of micronutrient iron species during the onset of convective mixing and sea-ice formation at this time of year, thereby setting conditions for primary production during the following spring. The spectacular field setting and remote, hostile conditions that accompany the proposed field study present exciting possibilities for STEM education and training. At the K-12 level, the project seeks to support the development of educational outreach materials targeting elementary and middle school students, pre-service science teachers, and in-service science teachers.
Abstract (non-technical) Sea level rise is a problem of global importance and it is increasingly affecting the tens of millions of Americans living along coastlines. The melting of glaciers in mountain areas worldwide in response to global warming is a major cause of sea level rise and increases in nuisance coastal flooding. However, the world's largest land-based ice sheets are situated in the Polar Regions and their response under continued warming is very difficult to predict. One reason for this uncertainty is a lack of observations of ice behavior and melt under conditions of warming, as it is a relatively new global climate state lasting only a few generations so far. Researchers will investigate ice growth on Antarctica under past warm conditions using geological archives embedded in the layers of sand and mud under the sea floor near Antarctica. By peeling back at the layers beneath the seafloor investigators can read the history book of past events affecting the ice sheet. The Antarctic continent on the South Pole, carries the largest ice mass in the world. The investigator's findings will substantially improve scientists understanding of the response of ice sheets to global warming and its effect on sea level rise. Abstract (technical) The melt of land based ice is raising global sea levels with at present only minor contributions from polar ice sheets. However, the future role of polar ice sheets in climate change is one of the most critical uncertainties in predictions of sea level rise around the globe. The respective roles of oceanic and atmospheric greenhouse forcing on ice sheets are poorly addressed with recent measurements of polar climatology, because of the extreme rise in greenhouse forcing the earth is experiencing at this time. Data on the evolution of the West Antarctic ice sheet is particularly sparse. To address the data gap, researchers will reconstruct the timing and spatial distribution of Antarctic ice growth through the last greenhouse to icehouse climate transition around 37 to 33 Ma. They will collect sedimentological and geochemical data on core samples from a high-latitude paleoarchive to trace the shutdown of the chemical weathering system, the onset of glacial erosion, ice rafting, and sea ice development, as East and West Antarctic ice sheets coalesced in the Weddell Sea sector. Their findings will lead to profound increases in the understanding of the role of greenhouse forcing in ice sheet development and its effect on the global climate system. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Ice cores contain detailed accounts of Earth's climate history. The collection of an ice core can be logistically challenging, and extraction of data from the core can be time-consuming as well as susceptible to both human and machine error. Furthermore, locked in measurements from ice cores is information that scientists have not yet found ways to recover. This project will apply techniques from information theory to ice-core data to unlock that information. The primary goal is to demonstrate that information theory can (a) identify regions of a specific ice-core record that are in need of further analysis and (b) provide some specific guidance for that analysis. A secondary goal is to demonstrate that information theory has practical and scientific utility for studies of past climate. This project aims to use information theory in two distinct ways: first, to identify regions of a core where information appears to be damaged or missing, perhaps due to human and/or machine error. In the segment of the West Antarctic Ice Sheet Divide core that is 5000-8000 years old, for instance, information-theoretic methods reveal significant levels of noise, probably due to a laboratory instrument, and something that was not visible in the raw data. This is a particularly important segment of the record, as it contains valuable clues about climatic shifts and the onset of the Holocene. Targeted re-sampling of this segment of the core and reanalysis with newer laboratory apparatus could resolve the data issues. The second way in which information theory can potentially aid in ice-core analysis is by extracting climate signals from the data--such as the accumulation rate at the core site over the period of its formation. This quantity usually requires significant time and effort to produce, but information theory could help to streamline that process. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Blankenship: 9319369 Bell: 9319854 Behrendt: 9319877 This award supports a project to conduct an integrated geophysical survey over a large portion of the West Antarctic Ice Sheet (WAIS) toward an understanding of the dynamic behavior of the ice sheet and the nature of the lithosphere beneath the ice sheet. West Antarctica is characterized by two kinds of the Earth s most dynamic systems, a continental rift (the West Antarctic Rift System) and a marine based ice sheet (the WAIS). Active continental rift systems, caused by divergent plate motions, result in thinned continental crust. Associated with the thin crust are fault-bounded sedimentary basins, active volcanism, and elevated heat flow. Marine ice sheets are characterized by rapidly moving streams of ice, penetrating and draining a slowly moving ice reservoir. Evidence left by past marine ice sheets indicates that they may have a strongly non- linear response to long-term climate change which results in massive and rapid discharges of ice. Understanding the evolution of the ice stream system and its interaction with the interior ice is the key to understanding this non-linear response. Subglacial geology and ice dynamics are generally studied in isolation, but evidence is mounting that the behavior of the West Antarctic ice streams may be closely linked to the nature of the underlying West Antarctic rift system. The fast moving ice streams appear to glide on a lubricating layer of water-saturated till. This till requires easily eroded sediment and a source of water, both of which may be controlled by the geology of the rift system; the sediments from the fault-bounded basins and the water from the elevated heat flux associated with active lithospheric extension. This project represents an interdisciplinary aerogeophysical study to characterize the lithosphere of the West Antarctic rift system beneath critical regions of the WAIS. The objective is to determine the effects of the rift architect ure, as manifested by the distribution of sedimentary basins and volcanic constructs, on the ice stream system. The research tool is a unique geophysical aircraft with laser altimetry, ice penetrating radar, aerogravity, and aeromagnetic systems integrated with a high precision kinematic GPS navigation system. It is capable of imaging both the surface and bed of the ice sheet while simultaneously measuring the gravity and magnetic signature of the subglacial lithosphere. Work to be done under this award will build on work already completed in the southern sector of central West Antarctica and it will focus on the region of the Byrd Subglacial Basin and Ice Stream D. The ice sheet in these regions is completely covered by satellite imagery and so this project will be integrated with remote sensing studies of the ice stream. The changing dynamics of Ice Stream D, as with other West Antarctic ice streams, seem to be correlated with changes in the morphological provinces of the underlying rift system. The experimental targets proceed from the divide of the interior ice, downstream through the onset of streaming to the trunk of Ice Stream D. This study will be coordinated with surface glaciological investigations of Ice Stream D and will be used to guide cooperative over-snow seismic investigations of the central West Antarctic rift system. The data will also be used to select a site for future deep ice coring along the crest of the WAIS. These data represent baseline data for long term global change monitoring work and represent crucial boundary conditions for ice sheet modeling efforts.
The ocean surrounding Antarctica is home to an extraordinary assemblage of fishes, dominated by a single group that are extremely well-suited to life in icy waters and which are of significant ecological importance there. Of great concern is the capacity of these fishes to withstand increases in temperature as the region of the Western Antarctic Peninsula warms at a rate faster than any other area in the Southern hemisphere. One particular group of Antarctic fishes, known as the icefishes, are particularly vulnerable to increases in temperature because unlike all other vertebrates on earth, icefishes are white-blooded due to their lack of the oxygen-binding protein hemoglobin. This greatly reduces their capacity to transport and deliver oxygen to tissues compared to red-blooded Antarctic fishes. Previous studies have shown that icefishes are indeed less tolerant to elevations in temperature but the underlying factors are completely unknown. Additionally, it is not understood if red- or white-blooded Antarctic fishes can adjust, or acclimate, to modest increases in temperature, similar to those changes in temperature the animals might experience as the earth warms. The investigators will determine if heart function and/or nervous system function limits thermal tolerance of Antarctic fishes, and will determine their capacity to acclimate to warmer temperatures. The project will further the NSF goal of training new generations of scientists by training graduate and undergraduate students. In addition, the project will collaborate with a high school biology teacher from a school which serves a largely minority student body. The students will learn about the marine environment, and will construct a camera to be used in the field to learn more about Antarctic fishes. Two students and the teacher will also attend a summer marine biology internship program. Antarctic fishes within the suborder Notothenioidei (called "notothenioids") are among the organisms on earth least able to deal with changes in temperature. The hemoglobinless icefish are even less able to withstand temperature changes than are red-blooded notothenioids. While this is well documented, the underlying physiological and biochemical mechanisms responsible are unknown. The investigators will test the hypotheses that cardiac work is significantly greater in icefishes compared to red-blooded species, and that as temperature increases, the greater cardiac work of icefishes, coupled with reduced blood oxygen-carrying capacity, results in cardiac failure at a lower temperature compared to red-blooded species. They also hypothesize that neuronal function limits thermal tolerance of red-blooded notothenioids. These hypotheses will be tested using a wide variety of experiments. For example, the investigators will measure heart rate concurrently with critical thermal maximum. They will also characterize metabolic and gene-expression responses to elevated temperature and determine if mitochondrial function contributes to thermal tolerance using a variety of techniques. To determine if neuronal function limits thermal tolerance they will quantify behavioral responses to warming of whole animals and to warming of only the brain area. They will also determine if acclimation to warmer temperatures impacts heart function and they will measure activities of a variety of enzymes from central metabolic pathways.
Intellectual Merit: Opening of Drake Passage and the West Scotia Sea south of Tierra del Fuego broke the final continental barrier to onset of a complete Antarctic Circumpolar Current (ACC). Initiation of the ACC has been associated in time with a major, abrupt, drop in global temperatures and the rapid expansion of the Antarctic ice sheets at 33-34 Ma. Events leading to the formation of the Drake Passage gateway are poorly known. Understanding the tectonic evolution of the floor of the Central Scotia Sea (CSS) and the North Scotia Ridge is a key to this understanding. Previous work has demonstrated that superimposed constructs formed a volcanic arc that likely blocked direct eastward flow from the Pacific to the Atlantic through the opening Drake Passage gateway as the active South Sandwich arc does today. The PIs propose a cruise to test, develop and refine, with further targeted mapping and dredging, their theory of CSS tectonics and the influence it had on the onset and development of the ACC. In addition they propose an installation of GPS receiver to test their paleogeographic reconstructions and determine whether South Georgia is moving as part of the South American plate. Broader impacts: A graduate student will be involved in all stages of the research. Undergraduate students will also be involved as watch-standers. A community college teacher will participate in the cruise. The PIs will have a website on which there will be images of the actual ocean floor dredging in operation. The teacher will participate with web and outreach support through PolarTREC. Results of the cruise are of broad interest to paleoceanographers, paleoclimate modelers and paleobiogeographers.
Antarctic fish and their early developmental stages are an important component of the food web that sustains life in the cold Southern Ocean (SO) that surrounds Antarctica. They feed on smaller organisms and in turn are eaten by larger animals, including seals and killer whales. Little is known about how rising ocean temperatures will impact the development of Antarctic fish embryos and their growth after hatching. This project will address this gap by assessing the effects of elevated temperatures on embryo viability, on the rate of embryo development, and on the gene "toolkits" that respond to temperature stress. One of the two species to be studied does not produce red blood cells, a defect that may make its embryos particularly vulnerable to heat. The outcomes of this research will provide the public and policymakers with "real world" data that are necessary to inform decisions and design strategies to cope with changes in the Earth's climate, particularly with respect to protecting life in the SO. The project will also further the NSF goals of training new generations of scientists, including providing scientific training for undergraduate and graduate students, and of making scientific discoveries available to the general public. This includes the unique educational opportunity for undergraduates to participate in research in Antarctica and engaging the public in several ways, including the development of professionally-produced educational videos with bi-lingual closed captioning. Since the onset of cooling of the SO about 40 million years ago, evolution of Antarctic marine organisms has been driven by the development of cold temperatures. Because body temperatures of Antarctic fishes fall in a narrow range determined by their habitat (-1.9 to +2.0 C) they are particularly attractive models for understanding how organismal physiology and biochemistry have been shaped to maintain life in a cooling environment. The long-term objective of this project is to understand the capacities of Antarctic fishes to acclimatize and/or adapt to rapid oceanic warming through analysis of their underlying genetic "toolkits." This objective will be accomplished through three Specific Aims: 1) assessing the effects of elevated temperatures on gene expression during development of embryos; 2) examining the effects of elevated temperatures on embryonic morphology and on the temporal and spatial patterns of gene expression; and 3) evaluating the evolutionary mechanisms that have led to the loss of the red blood cell genetic program by the white-blooded fishes. Aims 1 and 2 will be investigated by acclimating experimental embryos of both red-blooded and white-blooded fish to elevated temperatures. Differential gene expression will be examined through the use of high throughput RNA sequencing. The temporal and spatial patterns of gene expression in the context of embryonic morphology (Aim 2) will be determined by microscopic analysis of embryos "stained" with (hybridized to) differentially expressed gene probes revealed by Aim 1; other developmental marker genes will also be used. The genetic lesions resulting from loss of red blood cells by the white-blooded fishes (Aim 3) will be examined by comparing genes and genomes in the two fish groups.
During winter, sea-ice coverage along the Antarctic coast is punctuated by numerous polynyas--isolated openings of tens to hundreds of kilometer wide. These coastal polynyas are hotspots of sea ice production and the primary source regions of the bottom water in the global ocean. They also host high levels of biological activities and are the feeding grounds of Emperor penguins and marine mammals. The polynyas are a key component of the Antarctic coastal system and crucial for the survival of penguins and many other species. These features also differ dramatically from each other in timing of formation, duration, phytoplankton growth season, and overall biological productivity. Yet, the underlying reasons for differences among them are largely unknown. This project studies the fundamental biophysical processes at a variety of polynyas, examines the connection between the physical environment and the phytoplankton and penguin ecology, and investigates the mechanisms behind polynya variability. The results of this interdisciplinary study will provide a context for interpretation of field measurements in Antarctic coastal polynyas, set a baseline for future polynya studies, and examine how polynya ecosystems may respond to local and large-scale environmental changes. The project will include educational and outreach activities that convey scientific messages to a broad audience. It aims to increase public awareness of the interconnection between large-scale environmental change and Antarctic coastal systems. The main objectives of this study are to form a comprehensive understanding of the temporal and spatial variability of Antarctic coastal polynyas and the physical controls of polynya ecosystems. The project takes an interdisciplinary approach and seeks to establish a modeling system centered on the Regional Ocean Modeling System. This system links the ice and ocean conditions to the plankton ecology and penguin population. Applications of the modeling system in representative polynyas, in conjunction with analysis of existing observations, will determine the biophysical influences of individual forcing factors. In particular, this study will test a set of hypothesized effects of winds, offshore water intrusion, ice-shelf melting, sea-ice formation, glacier tongues, and ocean stratification on the timing of polynya phytoplankton bloom and the overall polynya biological productivity. The project will also examine how changing polynya state affects penguin breeding success, adult survival, and population growth. The team will conduct idealized sensitivity analysis to explore implications of forcing variability, including local and large-scale environmental change, on Antarctic coastal ecosystems.
Since the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~40-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. As circum-Antarctic coastal temperatures declined during this period from ~20°C to the modern ?1.9 to +2.0°C (reached ~8-10 million years ago), the psychrophilic (cold-loving) ectotherms of the Southern Ocean evolved compensatory molecular, cellular, and physiological traits that enabled them to maintain normal metabolic function at cold temperatures. Today, these organisms are threatened by rapid warming of the Southern Ocean over periods measured in centuries (as much as 5°C/100 yr), a timeframe so short that re-adaptation and/or acclimatization to the ?new warm? may not be possible. Thus, the long-term goals of this research project are: 1) to understand the biochemical and physiological capacities of the embryos of Antarctic notothenioid fish to resist or compensate for rapid oceanic warming; and 2) to assess the genetic toolkit available to support the acclimatization and adaptation of Antarctic notothenioid embryos to their warming habitat. The specific aims of this work are: 1) to determine the capacity of the chaperonin complex of notothenioid fishes to assist protein folding at temperatures between ?4 and +20°C; and 2) to evaluate the genetic responses of notothenioid embryos, measured as global differential gene transcription, to temperature challenge, with ?1.9°C as the ?normal? control and +4 and +10°C as high temperature insults. The physiology of embryonic development of marine stenotherms under future climate change scenarios is an important but understudied problem. This project will provide valuable insights into the capacity of Antarctic fish embryos to acclimatize and adapt to plausible climate change scenarios by examining multiple levels of biological organization, from the biochemical to the organismal. The results should also be broadly applicable to understanding the impact of global warming on marine biota worldwide. The research will also introduce graduate and REU undergraduate students to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem.
Waddington/1246045 This award supports a project to investigate the onset and growth of folds and other disturbances seen in the stratigraphic layers of polar ice sheets. The intellectual merit of the work is that it will lead to a better understanding of the grain-scale processes that control the development of these stratigraphic features in the ice and will help answer questions such as what processes can initiate such disturbances. Snow is deposited on polar ice sheets in layers that are generally flat, with thicknesses that vary slowly along the layers. However, ice cores and ice-penetrating radar show that in some cases, after conversion to ice, and following lengthy burial, the layers can become folded, develop pinch-and-swell structures (boudinage), and be sheared by ice flow, at scales ranging from centimeters to hundreds of meters. The processes causing these disturbances are still poorly understood. Disturbances appear to develop first at the ice-crystal scale, then cascade up to larger scales with continuing ice flow and strain. Crystal-scale processes causing distortions of cm-scale layers will be modeled using Elle, a microstructure-modeling package, and constrained by fabric thin-sections and grain-elongation measurements from the West Antarctic Ice Sheet divide ice-core. A full-stress continuum anisotropic ice-flow model coupled to an ice-fabric evolution model will be used to study bulk flow of anisotropic ice, to understand evolution and growth of flow disturbances on the meter and larger scale. Results from this study will assist in future ice-core site selection, and interpretation of stratigraphy in ice cores and radar, and will provide improved descriptions of rheology and stratigraphy for ice-sheet flow models.The broader impacts are that it will bring greater understanding to ice dynamics responsible for stratigraphic disturbance. This information is valuable to constrain depth-age relationships in ice cores for paleoclimate study. This will allow researchers to put current climate change in a more accurate context. This project will provide three years of support for a graduate student as well as support and research experience for an undergraduate research assistant; this will contribute to development of talent needed to address important future questions in glaciology and climate change. The research will be communicated to the public through outreach events and results from the study will be disseminated through public and professional meetings as well as journal publications. The project does not require field work in Antarctica.
Ocean acidification (OA) poses a serious threat, particularly to organisms that precipitate calcium carbonate from seawater. One organism with an aragonite shell that is a key to high latitude ecosystems is the pteropod. With OA, the pteropod shell will thin because the aragonite is highly soluble. As the shell thins, it changes the mass distribution and buoyancy of the animal, which will affect locomotion and through it, all locomotion dependent behavior such as foraging, mating, predator avoidance and migratory patterns. A lower shell weight will be counterbalanced by a smaller mucus web potentially decreasing ingestion rates and carbon flux rates. This interdisciplinary research relies on biological studies of swimming behavior of the pteropod mollusk Limacina helicina in their natural environments with fluid mechanics analyses of swimming hydrodynamics via 3D tomographic particle-image velocimetry and computational fluid dynamics (CFD). This work will: (a) determine how the L. helicina uses its 'wings' (parapodia) to propel itself; (b) examine whether its locomotory kinematics provide efficient propulsion; (c) identify the factors that influence swimming trajectory and 'wobble'; and (d) synthesize all data and insights into guidelines for the potential use of pteropod swimming behavior as a bioassay for OA. The loss of these sentinels of anthropogenic increases in CO2 may result in an ecological shift since thecosome pteropods are responsible for ingesting nearly half the primary production in the Southern Ocean and also serve as a primary food resource to upper trophic levels like fish. Since locomotory data can be gathered immediately, the bioassay being developed in this proposal may serve as an early warning of the impending onset of OA effects on this important member of the plankton. Students and researchers will collaborate in a rich interdisciplinary research environment by working with a biological oceanographer, a fluid mechanics expert and a CFD expert coupled with the teamsmanship needed for work in the Antarctic. By setting up a one-of-a-kind 3D tomography system for visualizing flow around planktonic organisms in Norway and at Palmer Station, we increase international exchange of state-of-the-art techniques. The educational impact of the current research will be multiplied by including in the research team, undergraduate students, high-school students and underrepresented minorities in addition to graduate students.
Intellectual Merit: This project will investigate glacial advance and retreat of the East Antarctic Ice Sheet through the Eocene-Oligocene transition, a major episode of ice growth. In Prydz Bay, East Antarctica, a 130-170 m thick Eocene-Oligocene transition interval of glaciomarine sediments was cored in drillholes of the Ocean Drilling Program at Sites 739, 742 and 1166. Correlations between the Prydz Bay drillholes have recently been made through well-log and multichannel seismic interpretations. Recent drilling on the Wilkes Land margin of East Antarctica recovered earliest Oligocene sediments overlying a major regional unconformity in two drillholes. The PI will study the lithostratigraphy and weathering history of cores in the five drillholes, to establish a unique Eocene-Oligocene transition record within Antarctic continental margin sediments of glacial advance and retreat cycles, the onset of physical weathering, and glacio-isostasy and self-gravitation processes with implications for the margin architecture, sediment routing, and off-shore sediment dispersal. Cores from the five drillholes will be re-examined through detailed core description using an updated classification scheme, so that lithofacies can be compared between drillholes. Samples will be collected for detailed laser particle size and bulk major element geochemistry via ICP-AES to determine the degree of chemical alteration of the sediments. Phases of major ice growth will be recognized as marker beds of physically eroded sediment and will be correlated to isotopic records documenting Antarctic ice growth offshore in the Southern Ocean. Broader impacts: This project will benefit a large minority undergraduate student population through the availability of up to two paid laboratory internships, a classroom exercise, and the availability of research equipment supported by this award. The project also allows support and training of a graduate student.
1245659/Petrenko This award supports a project to use the Taylor Glacier, Antarctica, ablation zone to collect ice samples for a range of paleoenvironmental studies. A record of carbon-14 of atmospheric methane (14CH4) will be obtained for the last deglaciation and the Early Holocene, together with a supporting record of CH4 stable isotopes. In-situ cosmogenic 14C content and partitioning of 14C between different species (14CH4, C-14 carbon monoxide (14CO) and C-14 carbon dioxide (14CO2)) will be determined with unprecedented precision in ice from the surface down to ~67 m. Further age-mapping of the ablating ice stratigraphy will take place using a combination of CH4, CO2, δ18O of oxygen gas and H2O stable isotopes. High precision, high-resolution records of CO2, δ13C of CO2, nitrous oxide (N2O) and N2O isotopes will be obtained for the last deglaciation and intervals during the last glacial period. The potential of 14CO2 and Krypton-81 (81Kr) as absolute dating tools for glacial ice will be investigated. The intellectual merit of proposed work includes the fact that the response of natural methane sources to continuing global warming is uncertain, and available evidence is insufficient to rule out the possibility of catastrophic releases from large 14C-depleted reservoirs such as CH4 clathrates and permafrost. The proposed paleoatmospheric 14CH4 record will improve our understanding of the possible magnitude and timing of CH4 release from these reservoirs during a large climatic warming. A thorough understanding of in-situ cosmogenic 14C in glacial ice (production rates by different mechanisms and partitioning between species) is currently lacking. Such an understanding will likely enable the use of in-situ 14CO in ice at accumulation sites as a reliable, uncomplicated tracer of the past cosmic ray flux and possibly past solar activity, as well as the use of 14CO2 at both ice accumulation and ice ablation sites as an absolute dating tool. Significant gaps remain in our understanding of the natural carbon cycle, as well as in its responses to global climate change. The proposed high-resolution, high-precision records of δ13C of CO2 would provide new information on carbon cycle changes both during times of rising CO2 in a warming climate and falling CO2 in a cooling climate. N2O is an important greenhouse gas that increased by ~30% during the last deglaciation. The causes of this increase are still largely uncertain, and the proposed high-precision record of N2O concentration and isotopes would provide further insights into N2O source changes in a warming world. The broader impacts of proposed work include an improvement in our understanding of the response of these greenhouse gas budgets to global warming and inform societally important model projections of future climate change. The continued age-mapping of Taylor Glacier ablation ice will add value to this high-quality, easily accessible archive of natural environmental variability. Establishing 14CO as a robust new tracer for past cosmic ray flux would inform paleoclimate studies and constitute a valuable contribution to the study of the societally important issue of climate change. The proposed work will contribute to the development of new laboratory and field analytical systems. The data from the study will be made available to the scientific community and the broad public through the NSIDC and NOAA Paleoclimatology data centers. 1 graduate student each will be trained at UR, OSU and SIO, and the work will contribute to the training of a postdoc at OSU. 3 UR undergraduates will be involved in fieldwork and research. The work will support a new, junior UR faculty member, Petrenko. All PIs have a strong history of and commitment to scientific outreach in the forms of media interviews, participation in filming of field projects, as well as speaking to schools and the public about their research, and will continue these activities as part of the proposed work. This award has field work in Antarctica.
Since the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~40-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. The biochemical and physiological challenges facing ectotherms living in the Southern Ocean include the reduction of reaction rates and metabolic fluxes and a pervasive weakening of macromolecular interactions. Yet, Southern Ocean ectotherms are now threatened by warming over periods measured in centuries or less. The proposed research seeks to understand the molecular mechanisms of cold adaptation in Antarctic marine fishes and to assess the physiological capacity of these organisms to resist or compensate for rapid oceanic warming. The P.I. will characterize two important and interacting protein systems, the tubulins that form microtubules and the chaperonin CCT (cytoplasmic chaperonin-containing TCP-1, a family of proteins that assists the folding of the tubulins). Higher-level, integrative responses to global temperature change will be analyzed by studying the thermal dependence of cleavage in Antarctic fish embryos (a microtubule-dependent process). The objectives are (1) to determine the contributions of five novel amino acid substitutions found in Antarctic fish beta-tubulins to microtubule assembly at cold temperature. (2) to compare the functional properties of CCT from testis tissues of Antarctic fishes and mammals. (3) to evaluate the effects of increased temperature on embryogenesis in Antarctic fishes. The research will introduce graduate and REU undergraduate students to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem. The proposed work also will benefit society by developing a cold-functioning chaperonin protein folding system, of great value to the biopharmaceutical and biotechnological industries for use in folding insoluble proteins.
Bell/0636883<br/><br/>This award support a project to study the role that subglacial water plays in the overall stability of major ice sheets. An estimated 22,000 km3 of water is currently stored within Antarctica's subglacial lakes. Movement of this water occurs through a complex and largely inferred drainage system in both East and West Antarctica. Geomorphic evidence for the catastrophic drainage of subglacial lakes documents repeated events. These major flood events appear to have drained the largest subglacial lakes situated in the relatively stable interior of the East Antarctic ice sheet. Emerging evidence suggests there is a close connection between significant subglacial lakes and the onset of the Recovery Ice Stream one of the largest in East Antarctica. Our preliminary analysis of the Recovery Lakes region, East Antarctica suggests a direct linkage between lakes and streaming ice flow, specifically the 800 km long Recovery Ice Stream and its tributaries. Located just upslope of the Recovery Ice Stream, the Recovery Lakes Region is composed of 3 well-defined lakes and a fourth, ambiguous, 'lake-like' feature. While other large lakes have a localized impact on ice surface slope, the Recovery Lakes Region lakes are coincident with an abrupt regional change in the ice sheet surface slope. Satellite imagery demonstrates that the downslope margin of this lake area contains distinct flow strips and crevasses: both indicative of increasing ice velocities. The discovery of a series of large lakes coincident with the onset of rapid ice flow in East Antarctica clearly links subglacial lakes and ice sheet dynamics for the first time. The evidence linking the onset of streaming in the Recovery Drainage Ice Stream to the series of large subglacial lakes raises the fundamental question: How can subglacial lakes trigger the onset of ice streaming? We advance two possible mechanisms: (i) Subglacial lakes can produce accelerated ice flow through the drainage of lake water beneath the ice sheet downslope of the lakes. (ii) Subglacial lakes can produce accelerated ice flow accelerated ice flow by modifying the basal thermal gradient via basal accretion over the lakes so when the ice sheet regrounds basal melting dominates. To evaluate the contribution of lake water and the changing basal thermal gradient, we propose an integrated program incorporating satellite imagery analysis, a series of reconnaissance aerogeophysical profiles over the Recovery Lake Region and the installation of continuous GPS sites over the Recovery Lakes. This analysis and new data will enable us (1) to produce a velocity field over the Recovery Lakes Region, (2) to map the ice thickness changes over the lakes due to acceleration triggered thinning, basal melting and freezing, (3) determine the depth and possible the tectonic origin of the Recovery Lakes and (4) determine the stability of these lakes over time. These basic data sets will enable us to advance our understanding of how subglacial lakes trigger the onset of streaming. The intellectual merit of this project is that it will be the first systematic analysis of ice streams triggering the onset of ice streams. This work has profound implications for the modeling of ice sheet behavior in the future, the geologic record of abrupt climate changes and the longevity of subglacial lakes. The broader impacts of the project are programs that will reach students of all ages through undergraduates involved in the research, formal presentations in teacher education programs and ongoing public outreach efforts at major science museums. Subglacial Antarctic lake environments are emerging as a premier, major frontier for exploration during the IPY 2007-2009.
Data collected on the permanently ice-covered lakes of the McMurdo Dry Valleys (MCM) during the late 1950's as part of the International Geophysical Year (IGY) showed that they were the only year round liquid water environments on the continent. Organisms in the lakes must possess novel physiological strategies that allow them to survive at low temperature and under extended darkness. Subsequent research has now shown that most organisms in the lakes are not just "surviving the extremes" but are actively feeding, growing and reproducing. However, nearly all research on the MCM lakes is restricted to the austral spring and summer when logistical support is provided. The unique aspects of physiological adaptation and metabolic function during the permanently cold and prolonged darkness of the Antarctic winter remain unknown. As part of the "International Polar Year 2007-2008" (IPY), the proposed research will study lakes within the Taylor Valley during the transition to polar night to test the overarching hypothesis that the onset of darkness induces a cascade of physiological changes that alters the functional role of autotrophic and heterotrophic microplankton within the lakes. This overarching theme will be addressed through an interdisciplinary study of selected biological components of the lake ecosystems using genomic and physiological tools to understand not only how individual organisms survive, but how they control ecosystem function during this seasonal transition. <br/><br/>This project is directly relevant to IPY objectives as it addresses a major identified theme (Adaptations to Life in Extreme Cold and Prolonged Darkness) with an international (UK, NZ),<br/>multidisciplinary team. The research has substantial broader impacts, as it will add to the body of long-term data accumulated by the MCM LTER and MCM Microbial Observatory projects in a synergistic manner; and it will include three undergraduates, a graduate student and two young female investigators. The project is linked to a highly visible education, outreach and human diversity programs supported by the McMurdo LTER, and initiates new outreach programs, including the Passport to Knowledge program.
Abstract<br/><br/>Since the advent of Antarctic continental glaciation, the opening of the Drake Passage between South America and the Antarctic Peninsula, and the onset of cooling of the Southern Ocean ~38-25 million years ago, evolution of the Antarctic marine biota has been driven by the development of extreme cold temperatures. Because they live at very low and stable temperatures, Antarctic fishes of the suborder Nototheniodei are particularly attractive as models for understanding the mechanisms of biomolecular cold adaptation, or the compensatory restructuring of biochemical and physiological systems to preserve biological function in cold thermal regimes. Two interrelated and potentially co-evolved systems, the tubulins that form microtubules and the chaperonin-containing TCP1 (t-complex protein-1) complex (CCT) that assists the folding of tubulins, provide an unparalleled opportunity to elucidate these mechanisms. This research will yield new and important knowledge regarding: 1) cold adaptation of microtubule assembly and of chaperonin function; and 2) the co-evolutionary origin of tubulin-binding specificity by CCT. The first objective of this proposal is to determine the contributions of five novel amino acid substitutions found in Antarctic fish beta-tubulins to microtubule assembly at cold temperature. The second objective is to establish a chaperonin folding system in vitro using CCT purified from testis tissue of Antarctic fishes and to evaluate its thermal properties and mechanism. The third objective is to evaluate, through phylogenetically controlled contrasts, the hypothesis that CCT and its tubulin substrates from Antarctic fishes have co-evolved to function at cold temperatures. The broader impacts of this proposal include introduction of graduate and REU undergraduate students of Northeastern University to state-of-the-art biochemical, cellular, and molecular-biological research relevant to ecological and environmental issues of the Antarctic marine ecosystem. Because much of the research on the biogenesis and function of cold-adapted proteins will be performed in the field at Palmer Station, these students will gain invaluable experience in the practical considerations of expeditionary biological science. The research also will increase knowledge about molecular cold adaptation in one of the Earth's extreme environments, and hence is relevant to the formulation of refined hypotheses regarding potential extraterrestrial life on Mars or Europa. The cold-functioning chaperonin protein folding system will be of great value to the biopharmaceutical and biotechnological industries for use in folding insoluble proteins.
9317598 Asper The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will focus on the collection of vertical flux samples which will be analyzed for carbon, nitrogen and total mass flux and also provided to the other investigators for their specific analyses. Profiles of the abundance of large aggregates in the water column using a non- contact photographic method will be made. These data will be used to complement other particle determinations, to investigate the role of these aggregates in particle flux and to determine the mechanisms of particle export as a function of season and phytoplankton species. The end result will be a better understanding of the bloom processes and significant contributions to the data base on aggregates and export mechanisms in this environment.
This award, provided by the Office of Polar Programs of the National Science Foundation, supports research to investigate the seismicity and tectonics of the South Shetland Arc and the Bransfield Strait. This region presents an intriguing and unique tectonic setting, with slowing of subduction, cessation of island arc volcanism, as well as the apparent onset of backarc rifting occurring within the last four million years. This project will carry out a 5-month deployment of 14 ocean bottom seismographs (OBSs) to complement and extend a deployment of 6 broadband land seismic stations that were successfully installed during early 1997. The OBSs include 2 instruments with broadband sensors, and all have flowmeters for measuring and sampling hydrothermal fluids. The OBSs will be used to examine many of the characteristics of the Shetland- Bransfield tectonic system, including: --- The existence and depth of penetration of a Shetland Slab: The existence of a downgoing Shetland slab will be determined from earthquake locations and from seismic tomography. The maximum depth of earthquake activity and the depth of the slab velocity anomaly will constrain the current configuration of the slab, and may help clarify the relationship between the subducting slab and the cessation of arc volcanism. -- Shallow Shetland trench seismicity?: No teleseismic shallow thrust faulting seismicity has been observed along the South Shetland Trench from available seismic information. Using the OBS data, the level of small earthquake activity along the shallow thrust zone will be determined and compared to other regions undergoing slow subduction of young oceanic lithosphere, such as Cascadia, which also generally shows very low levels of thrust zone seismicity. -- Mode of deformation along the Bransfield Rift: The Bransfield backarc has an active rift in the center, but there is considerable evidence for off-rift faulting. There is a long-standing controversy about whet her back-arc extension occurs along discrete rift zones, or is more diffuse geographically. This project will accurately locate small earthquakes to better determine whether Bransfield extension is discrete or diffuse. -- Identification of volcanism and hydrothermal activity: Seismic records will be used to identify the locations of active seafloor volcanism along the Bransfield rift. Flowmeters attached to the OBSs will record and sample the fluid flux out of the sediments. -- Upper mantle structure of the Bransfield - evidence for partial melting?: Other backarc basins show very slow upper mantle seismic velocities and high seismic attenuation, characteristics due to the presence of partially molten material. This project will use seismic tomography to resolve the upper mantle structure of the Bransfield backarc, allowing comparison with other backarc regions and placing constraints on the existence of partially molten material and the importance of partial melting as a mantle process in this region. Collaborative awards: OPP 9725679 and OPP 9726180
Luyendyk et.al.: OPP 0088143<br/>Bartek: OPP 0087392<br/>Diebold: OPP 0087983<br/><br/>This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative research program in marine geology and geophysics in the southern central and eastern Ross Sea. The project will conduct sites surveys for drilling from the Ross Ice Shelf into the seafloor beneath it. Many of the outstanding problems concerning the evolution of the East and West Antarctic Ice Sheets, Antarctic climate, global sea level, and the tectonic history of the West Antarctic Rift System can be addressed by drilling into the seafloor of the Ross Sea. Climate data for Cretaceous and Early Cenozoic time are lacking for this sector of Antarctica. Climate questions include: Was there any ice in Late Cretaceous time? What was the Antarctic climate during the Paleocene-Eocene global warming? When was the Cenozoic onset of Antarctic glaciation, when did glaciers reach the coast and when did they advance out onto the margin? Was the Ross Sea shelf non-marine in Late Cretaceous time; when did it become marine? Tectonic questions include: What was the timing of the Cretaceous extension in the Ross Sea rift; where was it located? What is the basement composition and structure? Where are the time and space limits of the effects of Adare Trough spreading? Another drilling objective is to sample and date the sedimentary section bounding the mapped RSU6 unconformity in the Eastern Basin and Central Trough to resolve questions about its age and regional extent. Deep Sea Drilling Project (DSDP) Leg 28 completed sampling at four drill sites in the early 1970's but had low recovery and did not sample the Early Cenozoic. Other drilling has been restricted to the McMurdo Sound area of the western Ross Sea and results can be correlated into the Victoria Land Basin but not eastward across basement highs. Further, Early Cenozoic and Cretaceous rocks have not been sampled. A new opportunity is developing to drill from the Ross Ice Shelf. This is a successor program to the Cape Roberts Drilling Project. One overriding difficulty is the need for site surveys at drilling locations under the ice shelf. This project will overcome this impediment by conducting marine geophysical drill site surveys at the front of the Ross Ice Shelf in the Central Trough and Eastern Basin. The surveys will be conducted a kilometer or two north of the ice shelf front where recent calving events have resulted in a southerly position of the ice shelf edge. In several years the northward advance of the ice shelf will override the surveyed locations and drilling could be accomplished. Systems to be used include swath bathymetry, gravity, magnetics, chirp sonar, high resolution seismic profiling, and 48 fold seismics. Cores will be collected to obtain samples for geotechnical properties, to study sub-ice shelf modern sedimentary processes, and at locations where deeper section is exposed.<br/><br/>This survey will include long profiles and detailed grids over potential drill sites. Survey lines will be tied to existing geophysical profiles and DSDP 270. A recent event that makes this plan timely is the calving of giant iceberg B-15 (in March, 2000) and others from the ice front in the eastern Ross Sea. This new calving event and one in 1987 have exposed 16,000 square kilometers of seafloor that had been covered by ice shelf for decades and is not explored. Newly exposed territory can now be mapped by modern geophysical methods. This project will map geological structure and stratigraphy below unconformity RSU6 farther south and east, study the place of Roosevelt Island in the Ross Sea rifting history, and determine subsidence history during Late Cenozoic time (post RSU6) in the far south and east. Finally the project will observe present day sedimentary processes beneath the ice shelf in the newly exposed areas.
9317538 Nelson The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will test the closely related hypotheses that: (1) phytoplankton growth is controlled primarily by the relationship between solar irradiance and mixed-layer depth throughout the spring (2) diatom growth rates are much higher in spring than at any other time of year, in response to the more favorable irradiance/mixing relationships, and (3) persistence of diatom blooms in summer results from the diatoms' ability to outcompete other groups under the light-limited conditions that develop in turbid, high-biomass waters. These hypotheses will be tested by (1) obtaining the first reliable estimates of the Sverdrup "critical depth" in the Antarctic so that the changing relationship between the critical depth and the mixed- layer depth in spring can be defined, and (2) estimating diatom growth rates and the gross and net production attributable to diatoms throughout the spring. The results will provide information critical to an understanding of phytoplankton bloom dynamics in the Ross Sea.
The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. The focus of this proposal is the role of microzooplankton in controlling the production and fate of carbon during the two types of blooms. Objectives are: 1) to determine biomass, abundance, size and selected species composition of primary producer assemblages, 2) to determine similar features of nano- and microplanktonic heterotrophic assemblages, 3) to measure total community grazing on heterotrophic bacteria and phytoplankton, 4) to examine which grazers are the major herbivores and bacterivores, and 5) to measure the contribution of microzooplankton and mesozooplankton egesta, sinking of algal cells and colonies, and sinking of protozoan assemblages associated with detritus to the total carbon flux from the euphotic zone through 250 m depth. Water samples for abundance and biomass determinations will be taken and samples will be examined with epifluorescence microscopy. Grazing rates will be measured using the dilution grazing technique and the dual-isotope radiolabeling single cell method. Carbon fluxes will be determined on sinking material collected with particle interceptor traps at the base of the euphotic zone and two deeper depths, using microscopical analysis . An understanding of these processes and other fundamental processes studied by collaborating investigators will contribute to the understanding of the role of the Southern Ocean in present, past and predicted future sequestration of carbon, as well as in other global elemental cycles.
The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will conduct a set of process-oriented experiments designed to elucidate the controls of phytoplankton productivity, growth and accumulation as well as the mechanisms which control bacterial abundance and productivity in Antarctic waters. Specifically, the relative photosynthetic and nutrient (nitrate, ammonium) characteristics of diatom- vs. Phaeocystis- dominated assemblages will be examined to test if Phaeocystis simply grows faster under spring conditions in the Ross Sea. Phytoplankton and bacterial biomass, productivity and their interactions will be measured to elucidate the complex physical-chemical-biological interactions which occur. Substantial understanding of the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions will result from this research. Finally, because the Antarctic is the ocean's largest high-nutrient, low biomass system, and hence has the greatest potential for sequestering carbon dioxide, knowledge of the dynamics of the Ross Sea phytoplankton will also increase our understanding of the carbo n cycle of the Southern Ocean.
The research will examine blood and muscle oxygen store depletion in relation to the documented aerobic dive limit (ADL, onset of post-dive blood lactate accumulation) in diving of emperor penguins. The intellectual merits of this proposal involve its evaluation of the physiological basis of the ADL concept. The ADL is probably the most commonly-used, but rarely measured, factor to interpret and model the behavior and foraging ecology of diving animals. Based on prior studies, and on recent investigations of respiratory and blood oxygen depletion during dives of emperor penguins, it is hypothesized that the ADL is a result of the depletion of myoglobin (Mb)-bound oxygen and increased glycolysis in the primary locomotory muscles. This project will accurately define the physiological mechanisms underlying the ADL through 1) evaluation of the rate and magnitude of muscle oxygen depletion during dives in relation to the previously measured ADL, 2) characterization of the hemoglobin-oxygen dissociation curve in blood of emperor penguins and comparison of that curve to those of other diving and non-diving species, 3) application of the emperor hemoglogin-oxygen dissociation curve to previously collected oxygen and hemoglobin data in order to estimate the rate and magnitude of blood oxygen depletion during dives, and 4) measurement of muscle phosphoocreatine and glycogen concentrations in order to estimate their potential contributions to muscle energy metabolism during diving. The project also continues the census and monitoring of the emperor colonies in the Ross Sea, which is especially important in light of both fisheries activity and the movement of iceberg B15-A. Broader impacts of the project include: 1) technological development of microprocessor-based, "backpack" near-infrared spectrophotometer, which will be applicable not only to other species, but also to other fields (i.e., exercise physiology), 2) collaboration with the Department of Anesthesia at the U.S. Naval Hospital in San Diego in the training of anesthesia residents in research techniques, 3) the training and thesis research of two graduate students in these techniques and in Antarctic field research, and 4) a better understanding of the ADL concept and its use in the fields of diving behavior and physiology. In addition the annual census of emperor penguin colonies in the Ross Sea, in conjunction with the continued evaluation of previously developed remote cameras to monitor colony status, will form the basis of a new educational web site, and allow development of an educational outreach program to school children through SeaWorld of San Diego.
This project is a field and laboratory based investigation of the Vanda dike swarm in the Dry Valleys of Antarctica. These dikes crosscut Cambro-Ordovician granitoid plutons produced during the Ross Orogeny, and mark the transition between the cessation of subduction and the onset of extensional magmatism. Many dying convergent plate margins convert to extensional magmatism, and the Dry Valleys provide a magnificent opportunity to examine the shallow roots of a plate that experienced this transition. Because of their exceptional exposure, bimodal felsic and mafic compositions, and complex field relations, the Vanda dikes have the potential to reveal insights into this important phase of Antarctic tectonic history. <br/>The broader impacts include collaboration between a primarily undergraduate and two research institutions, and support for undergraduate participation in an exciting, field-based research project.
This project will study migmatite domes found in the Fosdick Mountains of the Ford Ranges, western Marie Byrd Land, Antarctica. This area offers unique, three-dimensional exposures that may offer new insight into dome formation, which is a fundamental process of mountain building. These domes are derived from sedimentary and plutonic protoliths that are complexly interfolded at decimeter to kilometer scales. Preliminary findings from geobarometry and U-Pb monazite dating of anatexite suggest that peak metamorphism was underway at 105 Ma at crustal depths of ~25 km, followed by decompression as the Fosdick dome was emplaced to 16-17 km, or possibly as low as 8.5 km, in the crust by 99 Ma. Near-isothermal conditions were maintained during ascent, favorable for producing substantial volumes of melt through biotite-dehydration melting. This dome has been interpreted as a product of extensional exhumation. This is a viable interpretation from the regional standpoint, because the dome was emplaced in mid-Cretaceous time during the rapid onset of divergent tectonics along the proto- Pacific margin of Gondwana. However, the complex internal structures of the Fosdick Mountains have yet to be considered and may be more consistent with alternative intepretations such as upward extrusion within a contractional setting or lateral flow within a transcurrent attachment zone. This proposal is for detailed structural analysis, paired with geothermobarometry and geochronology, to determine the flow behavior and structural style that produced the internal architecture of the Fosdick dome. The results will improve our general understanding of the role of gneiss domes in transferring material and heat during mountain-building, and will characterize the behavior of the middle crust during a time of rapid transition from divergent to convergent tectonics along the active margin of Gondwana. In terms of broader impacts, this work will train undergraduate and graduate students, and involve them as collaborators in the development of curricular materials. It will also foster mentoring relationships between graduate and undergraduate students.
The emperor penguin, Aptenodytes forsteri, is the premier avian diver and a top predator in the Antarctic ecosystem. The routine occurrence of 500-m diver during foraging trips to sea is both a physiological and behavior enigma. The objectives of this project address how and why emperors dive as deep and long as they do. The project examines four major topics in the diving biology of emperor penguins: pressure tolerance, oxygen store management, end-organ tolerance of diving hypoxemia/ischemia, and deep-dive foraging behavior. These subjects are relevant to the role of the emperor as a top predator in the Antarctic ecosystem, and to critical concepts in diving physiology, including decompression sickness, nitrogen narcosis, shallow water blackout, hypoxemic tolerance, and extension of aerobic dive time. The following hypotheses will be tested: 1) Prevention of nitrogen narcosis and decompression sickness in emperor penguins is achieved by inhibition of pulmonary gas exchange at depth. 2) Shallow water black out does not occur because of greater cerebral hypoxemic tolerance, and, in deep dives, because of resumption of pulmonary gas exchange during final ascent. 3) The rate of depletion of the blood oxygen store is a function of depth of dive and heart rate. 4) The aerobic dive limit (ADL) reflects the onset of lactate accumulation in locomotory muscle, not total depletion of all oxygen stores. 5) Elevation of tissue antioxidant capacity and free-radical scavenging enzyme activities protect against the routine ischemia/reperfusion which occur during diving. 6) During deep dives, the Antarctic silverfish, Pleuorogramma antarcticum, is the primary prey item for emperors. <br/><br/>In addition to evaluation of the hypotheses below, the project has broader impacts in several areas such as partnership with foreign and national institutes and organizations (e.g., the National Institute of Polar Research of Japan, Centro de Investigacioines del Noroeste of Mexico, National Geographic, the University of Texas Southwestern Medical Center, and Sea World). Participation in National Geographic television documentaries will provide unique educational opportunities for the general public; development of state-of-the-art technology (e.g., blood oxygen electrode recorders, blood samplers, and miniaturized digital cameras) will lay the groundwork for future research by this group and others; and the effects of the B15 iceberg on breeding success of emperor penguins will continue to be evaluated with population censuses during planned fieldwork at several Ross Sea emperor penguin colonies.
9909436 Farley This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports an investigation of the uplift history of the Dry Valleys segment of the Transantarctic Mountains. The overall goal is to further constrain the exhumation history of the Transantarctic Mountains by using the newly developed apatite (U-Th)/He dating method on samples collected in vertical profiles. This approach, combined with existing apatite fission track information will constrain the rate and patterns of exhumation across the Transantarctic Mountains since their inception as a rift-flank uplift in the early Cenozoic. This project will complement other projects and build on previous interpretations of the exhumation and tectonic history determined using apatite fission track thermochronology. It will bridge the gap between information on erosion rates determined from fission track thermochronology and from cosmogenic surface exposure dating and integrate the exhumation history of the mountains with their landscape evolution. As such, the results from this project will address an outstanding problem in Antarctic science; namely the stability of the East Antarctic Ice Sheet, and the timing of the transition from a "warm" dynamic ice sheet to a cold polar ice sheet. Highly relevant to this issue is the landscape evolution of the Transantarctic Mountains because many diverse lines of evidence for the rate of landscape evolution have been used to argue for a dynamic ice sheet up until either the Pliocene (the "dynamic" ice sheet model) or the middle Miocene (the "stable" ice sheet model). Understanding the past stability or dynamic fluctuations of the East Antarctic ice sheet with respect to the climate record is, of course, important for understanding how the present ice sheet may respond to global warming. The specific objective of this project is to determine apatite (U-Th)/He age versus elevation trends for a number of vertical profiles from locations within the Transantarctic Mountain front and across the structural grain of the range. Fission track data already exist for all of these profiles, with apatite fission track ages ranging from 150-30 Ma. The greater precision of the (U-Th)/He technique and the fact it records information at lower temperatures (closure temperature of ~70 degrees Celsius; limits of 40-85 degrees Celsius for the He partial retention zone) will allow examination of the exhumation history of the TAM in more detail from ca 130 Ma to ~20 Ma. Another facet is to examine areas where Cretaceous exhumation is recorded and areas where the fission track profiles indicate periods of thermal and tectonic stability and minimal erosion throughout the Cretaceous. The variation of timing of the onset of more rapid exhumation accompanying uplift and formation of the Transantarctic Mountains in the early Cenozoic will also be examined.
9725882 Raymond This award is for support for a program of surface-based radio echo sounding to examine the geometry of the internal layering and the presence or absence of thawed zones outside the margins of active Ice Streams B and E and across the flow band feeding Ice Stream D. Melting in the marginal shear zone and/or on the bed outside an ice stream relates to the amount of support of the ice stream from the sides compared to the bed and the conditions that limit expansion of its width. Radar observations will be extended over the crest of adjacent inter-ice-stream ridges (B/C and D/E) and areas next to the flow band in the onset of D. The purpose is to examine internal layering indicative of the histories of these areas adjacent to ice streams and to determine whether ice streams have expanded into these presently stable areas in the past. These goals concerning the physical controls and history of ice stream width relate to how the discharge of ice streams has changed in the past and could change in the future to affect sea level.
This Small Grant for Exploratory Research supports development of a geochemical technique to time the onset of glacial erosion from Antarctica's continental ice sheets. The technique pairs neodymium (Nd) and hafnium (Hf) isotope proxies from the authigenic (seawater-derived) ferromanganese phase precipitated in marine sediments. This technique promises to be a sensitive indicator of glacial erosion. Non-radiogenic Hf is contained in the mineral zircon, which can only be released by the abrasive grinding that accompanies glacial erosion. Previous attempts to develop this technique encountered difficulty due to the minute amounts of Hf involved and the difficulty in its extraction. The PIs have developed a new chemical protocol that should allow them to selectively extract authigenic Hf from bulk sediments. If successful, studies of the Eocene-Oligocene boundary from two drill cores the Weddell Sea and Kerguelen Plateau will be carried out. This boundary is considered the initiation point for formation of Antarctica's current ice sheets. If successful, this method will benefit scientists with interests as diverse as continental weathering, ocean circulation, Cenozoic paleoceanography and paleoclimate, and Antarctic geology. <br/><br/>The broader impacts of this work are development of a new analytical technique that may improve society's understanding of the potential for global climate change from the perspective of the deep time record.
0125610<br/>Waddington<br/><br/>This award provides three years of funding to study the transition from slow inland flow to fast ice stream flow by making use of a suite of geophysical measurements that have been made near the onset region of ice stream D in West Antarctica. These data provide a unique opportunity to develop and validate glaciological models of the controlling processes in ice stream onset zones. Important processes to quantify are motion at the bed and deformation in the ice. Previous analyses indicate that the controlling resistive forces shift from the bed to the sides during the transition from slow inland flow to fast, streaming flow. Model sensitivity analyses will be used to investigate the relative importance of feedbacks between basal processes and ice deformation in the transition from inland to ice stream flow. Model experiments will determine what factors control the location of the onset of streaming flow, and how that location might migrate when conditions at the bed, or along the flow direction, changes over time. The overall goal of this work is to improve understanding of the evolution of the WAIS drainage system. This study is a first step towards understanding the physics that govern the transition from slow inland flow to fast streaming flow.
9814816 Blankenship This award supports a four year project to develop of better understanding the ice streams of the Ross Sea Embayment (A--F) which drain the interior West Antarctic Ice Sheet (WAIS) by rapidly moving vast quantities of ice to the calving front of the Ross Ice Shelf. The project will examine the role of these ice streams as buffers between the interior ice and the floating ice shelves. The reasons for their fast flow, the factors controlling their current grounding-line-, margin-, and head-positions are crucial to any attempt at modeling the WAIS system and predicting the future of the ice sheet. For the Antarctic ice streams of the Siple Coast, the transition from no-sliding (or all internal deformation) to motion dominated by sliding is defined as the "onset-region". To fully understand (and adequately model) the WAIS, this onset region must be better understood. The lateral margins of the ice streams are also a transition that need better explanation. Hypotheses on controls of the location of the onset region range from the "purely-glaciologic" to the "purely-geologic. Thus, to model the ice sheet accurately, the basal boundary conditions (roughness, wetness, till properties) and a good subglacial geologic map, showing the distribution, thickness, and properties of the sedimentary basins, are required. These parameters can be estimated from seismic, radar, and other geophysical methods. The transition region of ice stream D will be studied in detail with this coupled geophysical experiment. In addition, selected other locations on ice streams C & D will be made, to compare and contrast conditions with the main site on ice stream D. Site-selection for the main camp will be based on existing radar, GPS, and satellite data as well as input from the modeling community.
9318121 Anandakrishnan This award is for support for a three year project to test the hypothesis that a controlling parameter of fast ice-stream flow is the hydrologic state of discrete zones of high friction ("sticky spots") at the bed of the ice streams. Previous work has discovered an enormous difference in basal microearthquake activity between fast-flowing ice stream B and ice stream C, which stopped flowing within the last 200 years. It is hypothesized that the basal water system is lubricating the sticky spots under the fast ice stream and thus inhibiting microearthquake activity, and at the same time permitting fast ice flow. This experiment is intended to collect a continuous record of wide-bandwidth microearthquake data from a variety of sites, on the ice streams, in the transition zone, and on the inland ice. ***