[{"awards": "1841228 Lyons, W. Berry", "bounds_geometry": "POLYGON((163.37428 -77.558627,163.3922735 -77.558627,163.410267 -77.558627,163.4282605 -77.558627,163.446254 -77.558627,163.4642475 -77.558627,163.482241 -77.558627,163.5002345 -77.558627,163.518228 -77.558627,163.5362215 -77.558627,163.554215 -77.558627,163.554215 -77.56397510000001,163.554215 -77.5693232,163.554215 -77.5746713,163.554215 -77.5800194,163.554215 -77.5853675,163.554215 -77.59071560000001,163.554215 -77.5960637,163.554215 -77.60141180000001,163.554215 -77.6067599,163.554215 -77.612108,163.5362215 -77.612108,163.518228 -77.612108,163.5002345 -77.612108,163.482241 -77.612108,163.4642475 -77.612108,163.446254 -77.612108,163.4282605 -77.612108,163.410267 -77.612108,163.3922735 -77.612108,163.37428 -77.612108,163.37428 -77.6067599,163.37428 -77.60141180000001,163.37428 -77.5960637,163.37428 -77.59071560000001,163.37428 -77.5853675,163.37428 -77.5800194,163.37428 -77.5746713,163.37428 -77.5693232,163.37428 -77.56397510000001,163.37428 -77.558627))", "dataset_titles": "Commonwealth Stream Diel Water Chemistry; Hyporheic zone geochemistry of Wales Stream, Taylor Valley, Antarctica; isotopic signature of massive buried ice, eastern Taylor Valley, Antarctica", "datasets": [{"dataset_uid": "601844", "doi": "10.15784/601844", "keywords": "Antarctica; Commonwealth Stream; Cryosphere; Diel; Inlandwaters; McMurdo Dry Valleys; Stream Chemistry; Water Chemisty", "people": "Gardner, Christopher B.", "repository": "USAP-DC", "science_program": null, "title": "Commonwealth Stream Diel Water Chemistry", "url": "https://www.usap-dc.org/view/dataset/601844"}, {"dataset_uid": "601847", "doi": "10.15784/601847", "keywords": "Antarctica; Cryosphere; Nutrients; Stable Isotopes; Taylor Valley; Trace Elements", "people": "Gardner, Christopher B.", "repository": "USAP-DC", "science_program": null, "title": "Hyporheic zone geochemistry of Wales Stream, Taylor Valley, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601847"}, {"dataset_uid": "601848", "doi": "10.15784/601848", "keywords": "Antarctica; Buried Ice; Cryosphere; Stable Isotopes; Stable Water Isotopes; Taylor Valley", "people": "Gardner, Christopher B.", "repository": "USAP-DC", "science_program": null, "title": "isotopic signature of massive buried ice, eastern Taylor Valley, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601848"}], "date_created": "Wed, 16 Oct 2024 00:00:00 GMT", "description": "Phytoplankton, or microscopic marine algae, are an important part of the carbon cycle and can lower the rates of atmospheric carbon dioxide by transferring the atmospheric carbon into the oceans. The concentration of phytoplankton in the Southern Ocean is regularly limited by the availability of marine iron. This in turn influences the rate of carbon transfer from the atmosphere to the ocean. The primary source of iron in the Southern Ocean is eroded continental rock. Understanding the current and future sources of iron to the Southern Ocean as a result of increased melting of terrestrial glaciers is necessary for predicting future concentrations of Southern Ocean phytoplankton and the subsequent influence on the carbon cycle. A poorly understood source of iron to the Southern Ocean is stream input from ice-free regions such as the McMurdo Dry Valleys in Antarctica. This source of iron is likely to become larger if glaciers retreat. This study investigates the sources and amount of iron transported by McMurdo Dry Valley streams directly into the Southern Ocean. Because not all forms of iron can be used by phytoplankton, experiments will be performed to determine how available iron is to phytoplankton and how iron mixes with seawater. Immersive 360-degree video, infographics, and educational videos of findings from this project will be shared on social media, at schools and science events, and in an urban science center. In the Southern Ocean (SO) there is an excess of macronutrients but regional primary production is limited or co-limited due to iron. An addition of iron to the ocean will affect biochemical cycles, increase primary production, and affect the structure and composition of phytoplankton communities in the SO. Iron flux to the SO is globally significant, as increased Fe fertilization leads to increased carbon sequestration which acts as a negative feedback to increased atmospheric pCO2. One source of potentially bioavailable iron to the coastal regions of the SO is from direct sub-aerial stream discharge in ice-free areas of Antarctica, a source that may become more important if terrestrial glaciers retreat. It is imperative to understand the source, nature, potential fate, and flux of iron to the SO if better predictive models for the carbon cycle and atmospheric chemistry are to be developed. This project will investigate in-stream processes and characteristics controlling dissolved iron draining into the Ross Sea including photoreduction, temperature, and complexation with organic matter. The novel study will quantify bioavailability of particulate iron and bioavailability of dissolved iron in Antarctic in streams draining into the SO. On-site speciation measurements will be performed on dissolved iron species, particulate iron speciation will be determined using high-resolution spectroscopy, mixing experiments will be performed with coastal marine water, and the bioavailability of Fe will be determined through marine bioassays. This project will provide two students with valuable Antarctic field experience and reach thousands of individuals through existing partnerships with K-12 schools, public STEM events, an urban science center, and a strong social media presence. 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": 163.554215, "geometry": "POINT(163.4642475 -77.5853675)", "instruments": null, "is_usap_dc": true, "keywords": "SURFACE WATER CHEMISTRY; Iron Fertilization; McMurdo Dry Valleys; Weathering", "locations": "McMurdo Dry Valleys", "north": -77.558627, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Lyons, W. Berry; Gardner, Christopher B.", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.612108, "title": "Fe Behavior and Bioavailability in Sub-aerial Runoff into the Ross Sea", "uid": "p0010483", "west": 163.37428}, {"awards": "2142491 Young, Jodi", "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, 26 Jul 2023 00:00:00 GMT", "description": "Sea ice in Antarctic coastal waters shape ecosystems, both in the surface waters and at the bottom of the ocean, environments that depend on algae living in sea ice for their productivity. With high variability in sea ice formation and melt between years and as a response to climate change, it is of importance to obtain better understanding of the interaction of sea ice with algae, as well as provide better data for global climate models. This project will accomplish those goals by measuring phytoplankton growth and cellular properties in sea ice with experiments performed using an ice tank. Laboratory experiments will be based on previous observations in the Antarctic Peninsula coastal waters, providing realistic conditions to emulate. The scientific importance of the proposed work aligns with the National Science Foundation goals to understand the biological and chemical properties of sea ice bio-geo-chemistry and its feedbacks with seasonal sea ice dynamics and climate. The finding from this project will be of interest to a broad scientific community, including oceanographers, biologists, chemists, and ecosystem and ocean modelers. To address the scarcity of data on sea ice microbes that limits our ability to predict future Antarctic climate with accuracy, the principal investigator will develop an Antarctic Science Minor in order to train future scientists with an environmental perspective and prepare the future US workforce with a strong scientific background on Earth and Biological Sciences. There is a paucity of data to understand the processes underlying observed patters in sea ice quality and their interaction with the sea-ice microbial community. This project will provide a mechanistic understanding of primary production and physiology of sympagic algae over the seasonal cycle of formation and melt of Antarctic sea ice. Although sea ice is central to the Antarctic coastal ecosystems, little is known of how they affect, and are in turn affected, by sea-ice algae. This project concentrates on first-year sea ice, forming and melting each year, creating unique and very dynamic habitats. The study will be structured by 4 main objectives: 1) how different algal species adapt to the seasonal changes in sea ice conditions, 2) how different methods to measure primary production (carbon dioxide drawdown, oxygen production and variable fluorescence) relate in sea ice and differ from sea water measurements, 3) how sympagic algae influence the physical structure of sea ice, 4) how sympagic algae contribute to organic matter cycling during ice melt. Due to expected changes in sea ice due to climate change, this study is uniquely positioned to provide needed data on short-term and seasonal processes. Results from this study will be useful to refine models of algal production in Antarctic and Arctic ecosystems, data not available to date as sea ice and its biogeochemistry are often poorly represented in earth system models. This project will also provide education for graduate and undergraduate students as well as material to develop class curriculum for middle-school students. 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": "MARINE ECOSYSTEMS", "locations": null, "north": -60.0, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Young, Jodi", "platforms": null, "repositories": null, "science_programs": null, "south": -90.0, "title": "CAREER: Experimentally Testing the Role of Sympagic Algae in Sea-ice Environments using a Laboratory Scale Ice-tank.", "uid": "p0010425", "west": -180.0}, {"awards": "2135184 Arrigo, Kevin; 2135186 Baumberger, Tamara; 2135185 Resing, Joseph", "bounds_geometry": "POLYGON((155 -61,156.5 -61,158 -61,159.5 -61,161 -61,162.5 -61,164 -61,165.5 -61,167 -61,168.5 -61,170 -61,170 -61.2,170 -61.4,170 -61.6,170 -61.8,170 -62,170 -62.2,170 -62.4,170 -62.6,170 -62.8,170 -63,168.5 -63,167 -63,165.5 -63,164 -63,162.5 -63,161 -63,159.5 -63,158 -63,156.5 -63,155 -63,155 -62.8,155 -62.6,155 -62.4,155 -62.2,155 -62,155 -61.8,155 -61.6,155 -61.4,155 -61.2,155 -61))", "dataset_titles": null, "datasets": null, "date_created": "Fri, 30 Sep 2022 00:00:00 GMT", "description": "Phytoplankton blooms throughout the world\u2019s oceans support critical marine ecosystems and help remove carbon dioxide (CO2) from the atmosphere. Traditionally, it has been assumed that phytoplankton blooms in the Southern Ocean are stimulated by iron from either nearby land or sea-ice. However, recent work demonstrates that hydrothermal vents may be an additional iron source for phytoplankton blooms. This enhancement of phytoplankton productivity by different iron sources supports rich marine ecosystems and leads to the sequestration of carbon in the deep ocean. Our proposed work will uncover the importance of hydrothermal activity in stimulating a large phytoplankton bloom along the southern boundary of the Antarctic Circumpolar Current just north of the Ross Sea. It will also lead towards a better understanding of the overall impact of hydrothermal activity on the carbon cycle in the Southern Ocean, which appears to trigger local hotspots of biological activity which are a potential sink for atmospheric CO2. This project will encourage the participation of underrepresented groups in ocean sciences, as well as providing educational opportunities for high school and undergraduate students, through three different programs. Stanford University\u2019s Summer Undergraduate Research in Geoscience and Engineering (SURGE) program provides undergraduates from different US universities and diverse cultural backgrounds the opportunity to spend a summer doing a research project at Stanford. The Stanford Earth Summer Undergraduate Research Program (SESUR) is for Stanford undergraduates who want to learn more about environmental science by performing original research. Finally, Stanford\u2019s School of Earth, Energy, and Environmental Sciences High School Internship Program enables young scientists to serve as mentors, prepares high school students for college, and serves to strengthen the partnership between Stanford and local schools. Students present their results at the Fall AGU meeting as part of the AGU Bright STaRS program. This project will form the basis of at least two PhD dissertations. The Stanford student will participate in Stanford\u2019s Woods Institute Rising Environmental Leaders Program (RELP), a year-round program that helps graduate students hone their leadership and communication skills to maximize the impact of their research. The graduate student will also participate in Stanford\u2019s Grant Writing Academy where they will receive training in developing and articulating research strategies to tackle important scientific questions. This interdisciplinary program combines satellite and ship-based measurements of a large poorly understood phytoplankton bloom (the AAR bloom) in the northwestern Ross Sea sector of the Southern Ocean with a detailed modeling study of the physical processes linking deep dissolved iron (DFe) reservoirs to the surface phytoplankton bloom. Prior to the cruise, we will implement a numerical model (CROCO) for our study region so that we can better understand the circulation, plumes, turbulence, fronts, and eddy field around the AAR bloom and how they transport and mix hydrothermally produced DFe vertically. Post cruise, observations of the vertical distribution of 3He (combined with DMn and DFe), will be used as initial conditions for a passive tracer in the model, and tracer dispersal will be assessed to better quantify the role of the various turbulent processes in upwelling DFe-rich waters to the upper ocean. The satellite-based component of the program will characterize the broader sampling region before, during, and after our cruise. During the cruise, our automated software system at Stanford University will download and process images of sea ice concentration, Chl-a concentration, sea surface temperature (SST), and sea surface height (SSH) and send them electronically to the ship. Operationally, our goal is to use all available satellite data and preliminary model results to target shipboard sampling both geographically and temporally to optimize sampling of the AAR bloom. We will use available BGC-Argo float data to help characterize the AAR bloom. In collaboration with SOCCOM, we will deploy additional BGC-Argo floats (if available) during our transit through the study area to allow us to better characterize the bloom. The centerpiece of our program will be a 40-day process study cruise in austral summer. The cruise will consist of an initial \u201cradiator\u201d pattern of hydrographic surveys/sections along the AAR followed by CTDs to selected submarine volcanoes. When/if eddies are identified, they will be sampled either during or after the initial surveys. The radiator pattern, or parts thereof, will be repeated 2-3 times. Hydrographic survey stations will include vertical profiles of temperature, salinity, oxygen, oxidation-reduction potential, light scatter, and PAR (400-700 nm). Samples will be collected for trace metals, ligands, 3He, and total suspended matter. Where intense hydrothermal activity is identified, samples for pH and total CO2 will also be collected to characterize the hydrothermal system. Water samples will be collected for characterization of macronutrients, and phytoplankton physiology, abundance, species composition, and size. During transits, we will continuously measure atmospheric conditions, current speed and direction, and surface SST, salinity, pCO2, and fluorescence from the ship\u2019s systems to provide detailed maps of these parameters. The ship will be used as a platform for conducting phytoplankton DFe bioassay experiments at key stations throughout the study region both inside and outside the bloom. We will also perform detailed comparisons of algal taxonomic composition, physiology, and size structure inside and outside the bloom to determine the potential importance of each community on local biogeochemistry. 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": 170.0, "geometry": "POINT(162.5 -62)", "instruments": null, "is_usap_dc": true, "keywords": "BIOGEOCHEMICAL CYCLES; Antarctica; TRACE ELEMENTS; Hydrothermal Vent; Phytoplankton; Primary Production", "locations": "Antarctica", "north": -61.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Ocean and Atmospheric Sciences; Antarctic Integrated System Science; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Arrigo, Kevin; Thomas, Leif N; Baumberger, Tamara; Resing, Joseph", "platforms": null, "repositories": null, "science_programs": null, "south": -63.0, "title": "Collaborative Research: Understanding the Massive Phytoplankton Blooms over the Australian-Antarctic Ridge", "uid": "p0010381", "west": 155.0}, {"awards": "1744767 Sanders, Robert", "bounds_geometry": "POLYGON((-68 -64,-67.4 -64,-66.8 -64,-66.2 -64,-65.6 -64,-65 -64,-64.4 -64,-63.8 -64,-63.2 -64,-62.6 -64,-62 -64,-62 -64.5,-62 -65,-62 -65.5,-62 -66,-62 -66.5,-62 -67,-62 -67.5,-62 -68,-62 -68.5,-62 -69,-62.6 -69,-63.2 -69,-63.8 -69,-64.4 -69,-65 -69,-65.6 -69,-66.2 -69,-66.8 -69,-67.4 -69,-68 -69,-68 -68.5,-68 -68,-68 -67.5,-68 -67,-68 -66.5,-68 -66,-68 -65.5,-68 -65,-68 -64.5,-68 -64))", "dataset_titles": "Companion datasets to Diversity of microbial eukaryotes along the West Antarctic peninsula in austral spring.; Expedition Data of NBP1910; Expedition Data of NBP 2205; LMG1904 expedition data; NBP1910_protist_community_RNA Raw sequence reads; NBP2205_protist_community_RNA Raw sequence reads will be made available here after processing is completed", "datasets": [{"dataset_uid": "200147", "doi": "10.7284/908260", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "LMG1904 expedition data", "url": "https://www.rvdata.us/search/cruise/LMG1904"}, {"dataset_uid": "200320", "doi": "10.6084/m9.figshare.19514110.v3", "keywords": null, "people": null, "repository": "Figshare", "science_program": null, "title": "Companion datasets to Diversity of microbial eukaryotes along the West Antarctic peninsula in austral spring.", "url": "https://doi.org/10.6084/m9.figshare.19514110.v3"}, {"dataset_uid": "200325", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of NBP1910", "url": "https://www.rvdata.us/search/cruise/NBP1910"}, {"dataset_uid": "200365", "doi": "", "keywords": null, "people": null, "repository": "NCBI", "science_program": null, "title": "NBP1910_protist_community_RNA Raw sequence reads; NBP2205_protist_community_RNA Raw sequence reads will be made available here after processing is completed", "url": "https://www.ncbi.nlm.nih.gov/search/all/?term=PRJNA807326"}, {"dataset_uid": "200366", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of NBP 2205", "url": "https://www.rvdata.us/search/cruise/NBP2205"}], "date_created": "Wed, 27 Jul 2022 00:00:00 GMT", "description": "Traditional models of oceanic food chains have consisted of photosynthetic algae (phytoplankton) being ingested by small animals (zooplankton), which were ingested by larger animals (fish). These traditional models changed as new methods allowed recognition of the importance of bacteria and other non-photosynthetic protozoa in more complex food webs. More recently, the wide-spread existence of mixotrophs (organisms that can both photosynthesize and ingest food particles) and their importance as microbial predators has been recognized in many oceanographic areas. In the Southern Ocean, the only two surveys of mixotrophs have suggested that there may be seasonal differences in their importance as predators. During the long polar night (winter), the ability of mixotrophs to ingest particulate food may aid in their survival thus ensuring a sufficient population in spring to support a phytoplankton bloom once photosynthesis rates can increase. Thus mixotrophs may provide a critical early food source upon which zooplankton and larger animals depend on for growth and reproduction. This project will advance understanding of mixotroph diversity and their ecological impact within the Southern Ocean microbial food web. Specifically, efforts will be focused on mixotrophy in the western Antarctica peninsula region during the austral spring and autumn when there are likely to be changes in the relative importance of photosynthesis and ingestion to mixotrophs. The project will provide research opportunities for undergraduate and graduate students and a post-doctoral researcher. There will be real-time outreach from the Southern Ocean to the public via blogs and interviews, and to high school art students through an established program that blends science and art education. Despite traditional views of protists as either \"phototrophic\" or \"heterotrophic,\" there are many photosynthetic protists that consume prey (mixotrophy). Mixotrophy is a widespread phenomenon in aquatic systems and phytoplankton groups with known mixotrophic species, notably chrysophytes, cryptophytes, prymnesiophytes, prasinophytes and dinoflagellates, are present and often abundant in Antarctic waters. However, in the Southern Ocean, the presence of mixotrophic phytoflagellates has been surveyed only twice: in the Ross Sea during Austral spring 2008 and summer 2011. The primary goals of the project are to gain better understanding of mixotroph diversity and their ecological impact with respect to the Southern Ocean microbial food web. The contribution of mixotrophs to primary production and bacterial consumption is likely linked to the taxonomic composition of the community and the abundance of particular species. Abundances of novel mixotrophic species will be evaluated via qPCR, which will be coupled with assessments of rates of feeding and photosynthesis with the goal of describing how active mixotrophs direct the movement of carbon through food webs. These experiments will help the determination of how viable and widespread mixotrophy is as a nutritional strategy in polar waters and give direct information on the currently unknown diversity of mixotrophic taxa under different environmental conditions occurring in austral spring and autumn. Furthermore, the methods will simultaneously yield information on the whole communities of protists - mixotrophic, phototrophic and heterotrophic. In addition, a method to examine aspects of the taxonomic and functional diversities of the bacterivorous/mixotrophic community will be employed. A thymidine analog (BrdU) will be used to label DNA of eukaryotes feeding on bacteria. The BrdU-labeled eukaryotic DNA will be isolated using immunoprecipitation. High-throughput sequencing of the labeled DNA (bacterivores) versus unlabeled community DNA will determine the diversity of bacterivorous mixotrophs relative to other microeukaryotes. Flow cytometric sorting based on chlorophyll to focus on mixotrophic species. These approaches will elucidate a gap in current knowledge of the influence of microbial interactions in the Southern Ocean under different conditions. 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(-65 -66.5)", "instruments": null, "is_usap_dc": true, "keywords": "Antarctic Peninsula; PLANKTON; COASTAL", "locations": "Antarctic Peninsula", "north": -64.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Sanders, Robert; Gast, Rebecca; Jeffrey, Wade H.", "platforms": null, "repo": "R2R", "repositories": "Figshare; NCBI; R2R", "science_programs": null, "south": -69.0, "title": "Collaborative Research: Diversity and ecological impacts of Antarctic mixotrophic phytoplankton", "uid": "p0010357", "west": -68.0}, {"awards": "0003956 Burns, Jennifer; 9981683 Costa, Daniel", "bounds_geometry": "POLYGON((-70 -65,-69.5 -65,-69 -65,-68.5 -65,-68 -65,-67.5 -65,-67 -65,-66.5 -65,-66 -65,-65.5 -65,-65 -65,-65 -65.5,-65 -66,-65 -66.5,-65 -67,-65 -67.5,-65 -68,-65 -68.5,-65 -69,-65 -69.5,-65 -70,-65.5 -70,-66 -70,-66.5 -70,-67 -70,-67.5 -70,-68 -70,-68.5 -70,-69 -70,-69.5 -70,-70 -70,-70 -69.5,-70 -69,-70 -68.5,-70 -68,-70 -67.5,-70 -67,-70 -66.5,-70 -66,-70 -65.5,-70 -65))", "dataset_titles": "Crabeater seal oxygen stores", "datasets": [{"dataset_uid": "601583", "doi": "10.15784/601583", "keywords": "Antarctica; Crabeater Seal; GLOBEC; Hemoglobin; LMG0104; LMG0106; LMG0204; LMG0205; Marguerite Bay; Myoglobin; Oxygen Stores; Seals", "people": "Burns, Jennifer", "repository": "USAP-DC", "science_program": null, "title": "Crabeater seal oxygen stores", "url": "https://www.usap-dc.org/view/dataset/601583"}], "date_created": "Wed, 29 Jun 2022 00:00:00 GMT", "description": "This collaborative study between the University of California, Santa Cruz, Duke University, the University of South Florida, the University of Alaska-Anchorage, and the University of California, San Diego will examine the identification of biological and physical features associated with the abundance and distribution of individual Antarctic predators; the identification and characterization of biological \u0027hot spots\u0027 within the Western Antarctic Peninsula; and the development of temporally and spatially explicit models of krill consumption within the WAP by vertebrate predators. It is one of several data synthesis and modeling components that use the data obtained in the course of the field work of the Southern Ocean Global Ocean Ecosystems Dynamics (SO GLOBEC) experiment.\u003cbr/\u003eSO-Globec is a multidisciplinary effort focused on understanding the physical and biological factors that influence growth, reproduction, recruitment and survival of Antarctic krill (Euphausia superba). The program uses a multi-trophic level approach that includes the predators and competitors of Antarctic krill, represented by other zooplankton, fish, penguins, seals, and cetaceans. It is currently in a synthesis and modeling phase. This collaborative project is concerned with understanding how predators utilize \u0027hot spots\u0027, i.e. locally intense areas of biological productivity, and how \u0027hot spots\u0027 might temporally and spatially structure krill predation rates, and will be integrated with other synthesis and modeling studies that deal with the hydrography primary production, and krill dynamics.", "east": -65.0, "geometry": "POINT(-67.5 -67.5)", "instruments": null, "is_usap_dc": true, "keywords": "Marguerite Bay; MARINE ECOSYSTEMS", "locations": "Marguerite Bay", "north": -65.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Burns, Jennifer; Costa, Daniel", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -70.0, "title": "Foraging Ecology of Crabeater Seals (Lobodon Carcinophagus)", "uid": "p0010345", "west": -70.0}, {"awards": "1643652 Hofmann, Eileen; 1643618 Arrigo, Kevin", "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": "Antarctic biological model output; Antarctic dFe model dyes", "datasets": [{"dataset_uid": "200211", "doi": "10.26008/1912/bco-dmo.858663.1", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Antarctic biological model output", "url": "https://www.bco-dmo.org/dataset/858663"}, {"dataset_uid": "200210", "doi": "10.26008/1912/bco-dmo.782848.1", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Antarctic dFe model dyes", "url": "https://www.bco-dmo.org/dataset/782848"}], "date_created": "Thu, 29 Apr 2021 00:00:00 GMT", "description": "Coastal waters surrounding Antarctica represent some of the most biologically rich and most untouched ecosystems on Earth. In large part, this biological richness is concentrated within the numerous openings that riddle the expansive sea ice (these openings are known as polynyas) near the Antarctic continent. These polynyas represent regions of enhanced production known as hot-spots and support the highest animal densities in the Southern Ocean. Many of them are also located adjacent to floating extensions of the vast Antarctic Ice Sheet and receive a substantial amount of meltwater runoff each year during the summer. However, little is known about the specific processes that make these ecosystems so biologically productive. Of the 46 Antarctic coastal polynyas that are presently known, only a handful have been investigated in detail. This project will develop ecosystem models for the Ross Sea polynya, Amundsen polynya, and Pine Island polynya; three of the most productive Antarctic coastal polynyas. The primary goal is to use these models to better understand the fundamental physical, chemical, and biological interacting processes and differences in these processes that make these systems so biologically productive yet different in some respects (e.g. size and productivity) during the present day settings. Modeling efforts will also be extended to potentially assess how these ecosystems may have functioned in the past and how they might change in the future under different physical and chemical and climatic settings. The project will advance the education of underrepresented minorities through Stanford?s Summer Undergraduate Research in Geoscience and Engineering (SURGE) Program. SURGE will provide undergraduates the opportunity to gain mentored research experiences at Stanford University in engineering and the geosciences. Old Dominion University also will utilize an outreach programs for local public and private schools as well as an ongoing program supporting the Boy Scout Oceanography merit badge program to create outreach and education impacts. Polynyas (areas of open water surrounded by sea ice) are disproportionately productive regions of polar ecosystems, yet controls on their high rates of production are not well understood. This project will provide quantitative assessments of the physical and chemical processes that control phytoplankton abundance and productivity within polynyas, how these differ for different polynyas, and how polynyas may change in the future. Of particular interest are the interactions among processes within the polynyas and the summertime melting of nearby ice sheets, including the Thwaites and Pine Island glaciers. In this proposed study, we will develop a set of comprehensive, high resolution coupled physical-biological models and implement these for three major, but diverse, Antarctic polynyas. These polynyas, the Ross Sea polynya, the Amundsen polynya, and Pine Island polynya, account for \u003e50% of the total Antarctic polynya production. The research questions to be addressed are: 1) What environmental factors exert the greatest control of primary production in polynyas around Antarctica? 2) What are the controlling physics that leads to the heterogeneity of dissolved iron (dFe) supply to the euphotic zone in polynyas around the Antarctic continental shelf? What effect does this have on local rates of primary production? 3) What are the likely changes in the supply of dFe to the euphotic zone in the next several decades due to climate-induced changes in the physics (winds, sea-ice, ice shelf basal melt, cross-shelf exchange, stratification and vertical mixing) and how will this affect primary productivity around the continent? The Ross Sea, Amundsen, and Pine Island polynyas are some of the best-sampled polynyas in Antarctica, facilitating model parameterization and validation. Furthermore, these polynyas differ widely in their size, location, sea ice dynamics, relationship to melting ice shelves, and distance from the continental shelf break, making them ideal case studies. For comparison, the western Antarctic Peninsula (wAP), a productive continental shelf where polynyas are a relatively minor contributor to biological production, will also be modeled. Investigating specific processes within different types Antarctic coastal waters will provide a better understand of how these important biological oases function and how they might change under different environmental conditions.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "Trace Metal; AMD; PELAGIC; POLYNYAS; PHYTOPLANKTON; MODELS; Amd/Us; USAP-DC; MICROALGAE; USA/NSF; Polynya; TRACE ELEMENTS; ICE SHEETS; Antarctica", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "van Dijken, Gert; Arrigo, Kevin; Dinniman, Michael; Hofmann, Eileen", "platforms": "OTHER \u003e MODELS \u003e MODELS", "repo": "BCO-DMO", "repositories": "BCO-DMO", "science_programs": null, "south": -90.0, "title": "Collaborative Research: Elucidating Environmental Controls of Productivity in Polynas and the Western Antarctic Peninsula", "uid": "p0010175", "west": -180.0}, {"awards": "1643466 Hollibaugh, James; 1643345 Popp, Brian", "bounds_geometry": "POLYGON((-78.20206667 -64.03195833,-76.785055836 -64.03195833,-75.368045002 -64.03195833,-73.951034168 -64.03195833,-72.534023334 -64.03195833,-71.1170125 -64.03195833,-69.700001666 -64.03195833,-68.282990832 -64.03195833,-66.865979998 -64.03195833,-65.448969164 -64.03195833,-64.03195833 -64.03195833,-64.03195833 -64.554377497,-64.03195833 -65.076796664,-64.03195833 -65.599215831,-64.03195833 -66.121634998,-64.03195833 -66.644054165,-64.03195833 -67.166473332,-64.03195833 -67.688892499,-64.03195833 -68.211311666,-64.03195833 -68.733730833,-64.03195833 -69.25615,-65.448969164 -69.25615,-66.865979998 -69.25615,-68.282990832 -69.25615,-69.700001666 -69.25615,-71.1170125 -69.25615,-72.534023334 -69.25615,-73.951034168 -69.25615,-75.368045002 -69.25615,-76.785055836 -69.25615,-78.20206667 -69.25615,-78.20206667 -68.733730833,-78.20206667 -68.211311666,-78.20206667 -67.688892499,-78.20206667 -67.166473332,-78.20206667 -66.644054165,-78.20206667 -66.121634998,-78.20206667 -65.599215831,-78.20206667 -65.076796664,-78.20206667 -64.554377497,-78.20206667 -64.03195833))", "dataset_titles": "\"Collaborative research: Chemoautotrophy in Antarctic bacterioplankton communities supported by the oxidation of urea-derived nitrogen\"; Expedition data of LMG1801", "datasets": [{"dataset_uid": "200124", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1801", "url": "https://www.rvdata.us/search/cruise/LMG1801"}, {"dataset_uid": "200193", "doi": "Not yet assigned", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "\"Collaborative research: Chemoautotrophy in Antarctic bacterioplankton communities supported by the oxidation of urea-derived nitrogen\"", "url": "https://www.bco-dmo.org/project/775717"}], "date_created": "Fri, 18 Dec 2020 00:00:00 GMT", "description": "Part 1: Nitrification is the conversion of ammonium to nitrate by a two-step process involving two different guilds of microorganisms: ammonia- and nitrite-oxidizers. The process is central to the global nitrogen cycle, affecting everything from retention of fertilizer on croplands to removal of excess nitrogen from coastal waters before it can cause blooms of harmful algae. It also produces nitrous oxide, an ozone-destroying, greenhouse gas. The energy derived from both steps of nitrification is used to convert inorganic carbon into microbial biomass. The biomass produced contributes to the overall food web production of the Southern Ocean and may be a particularly important subsidy during winter when low light levels restrict the other major source of biomass, primary production by single-celled plants. This project addresses three fundamental questions about the biology and geochemistry of polar oceans, with a focus on the process of nitrification. The first question the project will address concerns the contribution of chemoautotrophy (based on nitrification) to the overall supply of organic carbon to the food web of the Southern Ocean. Previous measurements indicate that it contributes about 9% to the Antarctic food web on an annual basis, but those measurements did not include the additional production associated with nitrite oxidation. The second question to be addressed is related to the first and concerns the coupling between the steps of the process. The third seeks to determine the significance of the contribution of other sources of nitrogen, (specifically organic nitrogen and urea released by other organisms) to nitrification because these contributions may not be assessed by standard protocols. Measurements made by others suggest that urea in particular might be as important as ammonium to nitrification in polar regions. This project will result in training a postdoctoral researcher and provide undergraduate students opportunities to gain hand-on experience with research on microbial geochemistry. The Palmer LTER (PAL) activities have focused largely on the interaction between ocean climate and the marine food web affecting top predators. Relatively little effort has been devoted to studying processes related to the microbial geochemistry of nitrogen cycling as part of the Palmer Long Term Ecological Research (LTER) program, yet these are a major themes at other sites. This work will contribute substantially to understanding an important aspect of nitrogen cycling and bacterioplankton production in the PAL-LTER study area. The team will be working synergistically and be participating fully in the education and outreach efforts of the Palmer LTER, including making highlights of the findings available for posting to their project web site and participating in any special efforts they have in the area of outreach. Part 2: The proposed work will quantify oxidation rates of 15N supplied as ammonium, urea and nitrite, allowing us to estimate the contribution of urea-derived N and complete nitrification (ammonia to nitrate) to chemoautotrophy and bacterioplankton production in Antarctic coastal waters. The project will compare these estimates to direct measurements of the incorporation of 14C into organic matter the dark for an independent estimate of chemoautotrophy. The team aims to collect samples spanning the water column: from surface water (~10 m), winter water (50-100 m) and circumpolar deep water (\u003e150 m); on a cruise surveying the continental shelf and slope west of the Antarctic Peninsula in the austral summer of 2018. Other samples will be taken to measure the concentrations of nitrate, nitrite, ammonia and urea, for qPCR analysis of the abundance of relevant microorganisms, and for studies of related processes. The project will rely on collaboration with the existing Palmer LTER to ensure that ancillary data (bacterioplankton abundance and production, chlorophyll, physical and chemical variables) will be available. The synergistic activities of this project along with the LTER activities will provide a unique opportunity to assess chemoautotrophy in context of the overall ecosystem?s dynamics- including both primary and secondary production processes.", "east": -64.03195833, "geometry": "POINT(-71.1170125 -66.644054165)", "instruments": null, "is_usap_dc": true, "keywords": "Pal-Lter; NITROGEN; SHIPS; USAP-DC; MARINE ECOSYSTEMS; BACTERIA/ARCHAEA; BIOGEOCHEMICAL CYCLES; Amd/Us; West Antarctic Shelf; USA/NSF; AMD", "locations": "West Antarctic Shelf; Pal-Lter", "north": -64.03195833, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Hollibaugh, James T.; Popp, Brian", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e SHIPS", "repo": "R2R", "repositories": "BCO-DMO; R2R", "science_programs": null, "south": -69.25615, "title": "Collaborative Research: Chemoautotrophy in Antarctic Bacterioplankton Communities Supported by the Oxidation of Urea-derived Nitrogen", "uid": "p0010150", "west": -78.20206667}, {"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": "001363", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "NBP1704 Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP1704"}, {"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"}], "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": "R2R", "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": "1543328 Van Mooy, Benjamin", "bounds_geometry": null, "dataset_titles": "Lipidomics of Antarctic waters. (TBD)", "datasets": [{"dataset_uid": "200149", "doi": "TBD", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Lipidomics of Antarctic waters. (TBD)", "url": "https://www.bco-dmo.org/data"}], "date_created": "Fri, 19 Jun 2020 00:00:00 GMT", "description": "The depletion of stratospheric ozone over Antarctica leads to abnormally high levels of ultraviolet radiation (UVR) from the sun reaching the surface of the ocean. This phenomenon is predicted to continue for the next half century, despite bans on ozone-destroying pollutants. Phytoplankton in the near surface ocean are subjected to variable amounts of UVR and contain a lot of lipids (fats). Because phytoplankton are at the base of the food chain their lipids makes their way into the Antarctic marine ecosystem\u0027s food web. The molecular structures of phytoplankton lipids are easily altered by UVR. When this happens, their lipids can be transformed from healthy molecules into potentially harmful molecules(oxylipins) known to be disruptive to reproductive and developmental processes. This project will use state-of-the-art molecular methods to answer questions about extent to which UVR damages lipid molecules in phytoplankton, and how these resultant molecules might effect the food chain in the ocean near Antarctica. Lipid peroxidation is often invoked as consequence of increased exposure of phytoplankton to UVR-produced reactive oxygen species (ROS), but the literature is practically silent on peroxidized lipids and their byproducts (i.e. oxylipins) in the ocean. In waters of the West Antarctic Peninsula (WAP), spring-time blooms of diatoms contribute significantly to overall marine primary production. Oxylipins from diatoms can be highly bioactive; their impact on zooplankton grazers, bacteria, and other phytoplankton has been the subject of intense study. However, almost all of this work has focused on the production of oxylipins via enzymatic pathways, not by pathways involving UVR and/or ROS. Furthermore, rigorous experimental work on the effects of oxylipins has been confined almost exclusively to pure cultures and artificial communities. Thus, the true potential of these molecules to disrupt carbon cycling is very poorly-constrained, and is entirely unknown in the waters of the WAP. Armed with new highly-sensitive, state-of-the-art analytical techniques based on high-mass-resolution mass spectrometry, the principal investigator and his research group have begun to uncover an exquisite diversity of oxylipins in natural WAP planktonic communities. These techniques will be applied to understand the connections between UVR, ROS, oxylipins, and carbon cycling. The project will answer the question of how UVR, via ROS, affects oxylipin production by diatoms in WAP surface waters in controlled experiments conducted at a field station. With the answer to this question in hand, the project will also seek to answer how this phenomenon impacts the flow of carbon, particularly the export of organic carbon from the system, during a research cruise. The level of UVR-induced stresses experienced by oxylipin-rich planktonic communities in the WAP is unique, making Antarctica the only location for answering these fundamental questions. Major activities will include laboratory experiments with artificial membranes and diatom cultures, as well field experiments with phytoplankton, zooplankton, and bacteria in WAP waters.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "Oxylipins; Palmer Station; UV Radiation; USAP-DC; West Antarctic Shelf; NOT APPLICABLE; AQUATIC SCIENCES; Phytoplankton", "locations": "West Antarctic Shelf; Palmer Station", "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Van Mooy, Benjamin", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "BCO-DMO", "repositories": "BCO-DMO", "science_programs": null, "south": null, "title": "Production and Fate of Oxylipins in Waters of the Western Antarctic Peninsula: Linkages Between UV Radiation, Lipid Peroxidation, and Carbon Cycling", "uid": "p0010109", "west": null}, {"awards": "1744645 Young, Jodi", "bounds_geometry": "POLYGON((-64.4 -64.2,-64.38 -64.2,-64.36 -64.2,-64.34 -64.2,-64.32 -64.2,-64.3 -64.2,-64.28 -64.2,-64.26 -64.2,-64.24 -64.2,-64.22 -64.2,-64.2 -64.2,-64.2 -64.26,-64.2 -64.32,-64.2 -64.38,-64.2 -64.44,-64.2 -64.5,-64.2 -64.56,-64.2 -64.62,-64.2 -64.68,-64.2 -64.74,-64.2 -64.8,-64.22 -64.8,-64.24 -64.8,-64.26 -64.8,-64.28 -64.8,-64.3 -64.8,-64.32 -64.8,-64.34 -64.8,-64.36 -64.8,-64.38 -64.8,-64.4 -64.8,-64.4 -64.74,-64.4 -64.68,-64.4 -64.62,-64.4 -64.56,-64.4 -64.5,-64.4 -64.44,-64.4 -64.38,-64.4 -64.32,-64.4 -64.26,-64.4 -64.2))", "dataset_titles": "Dataset: Particulate Organic Carbon and Particulate Nitrogen; Dataset: Photosynthetic Pigments; Dataset: Physical Profiles of Temperature, Salinity, and Brine Volume; Sea-ice diatom compatible solute shifts", "datasets": [{"dataset_uid": "200378", "doi": "10.26008/1912/bco-dmo.913655.1", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Dataset: Physical Profiles of Temperature, Salinity, and Brine Volume", "url": "https://www.bco-dmo.org/dataset/913655"}, {"dataset_uid": "200377", "doi": "10.26008/1912/bco-dmo.913222.1", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Dataset: Photosynthetic Pigments", "url": "https://www.bco-dmo.org/dataset/913222"}, {"dataset_uid": "200322", "doi": "10.21228/M84386", "keywords": null, "people": null, "repository": "Metabolomics workbench", "science_program": null, "title": "Sea-ice diatom compatible solute shifts", "url": "https://www.metabolomicsworkbench.org/data/DRCCMetadata.php?Mode=Study\u0026StudyID=ST001393"}, {"dataset_uid": "200376", "doi": "10.26008/1912/bco-dmo.913566.1", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Dataset: Particulate Organic Carbon and Particulate Nitrogen", "url": "https://www.bco-dmo.org/dataset/913566"}], "date_created": "Tue, 23 Jul 2019 00:00:00 GMT", "description": "Rapid changes in the extent and thickness of sea ice during the austral spring subject microorganisms within or attached to the ice to large fluctuations in temperature, salinity, light and nutrients. This project aims to identify cellular responses in sea-ice algae to increasing temperature and decreasing salinity during the spring melt along the western Antarctic Peninsula and to determine how associated changes at the cellular level can potentially affect dynamic, biologically driven processes. Understanding how sea-ice algae cope with, and are adapted to, their environment will not only help predict how polar ecosystems may change as the extent and thickness of sea ice change, but will also provide a better understanding of the widespread success of photosynthetic life on Earth. The scientific context and resulting advances from the research will be communicated to the general public through outreach activities that includes work with Science Communication Fellows and the popular Polar Science Weekend at the Pacific Science Center in Seattle, Washington. The project will provide student training to college students as well as provide for educational experiences for K-12 school children. There is currently a poor understanding of feedback relationships that exist between the rapidly changing environment in the western Antarctic Peninsula region and sea-ice algal production. The large shifts in temperature and salinity that algae experience during the spring melt affect critical cellular processes, including rates of enzyme-catalyzed reactions involved in photosynthesis and respiration, and the production of stress-protective compounds. These changes in cellular processes are poorly constrained but can be large and may have impacts on local ecosystem productivity and biogeochemical cycles. In particular, this study will focus on the thermal sensitivity of enzymes and the cycling of compatible solutes and exopolymers used for halo- and cryo-protection, and how they influence primary production and the biogeochemical cycling of carbon and nitrogen. Approaches will include field sampling during spring melt, incubation experiments of natural sea-ice communities under variable temperature and salinity conditions, and controlled manipulation of sea-ice algal species in laboratory culture. Employment of a range of techniques, from fast repetition rate fluorometry and gross and net photosynthetic measurements to metabolomics and enzyme kinetics, will tease apart the mechanistic effects of temperature and salinity on cell metabolism and primary production with the goal of quantifying how these changes will impact biogeochemical processes along the western Antarctic Peninsula. 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": -64.2, "geometry": "POINT(-64.3 -64.5)", "instruments": null, "is_usap_dc": true, "keywords": "USAP-DC; SHIPS; DIATOMS; Antarctic Peninsula", "locations": "Antarctic Peninsula", "north": -64.2, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Young, Jodi; Deming, Jody", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e SHIPS", "repo": "BCO-DMO", "repositories": "BCO-DMO; Metabolomics workbench", "science_programs": null, "south": -64.8, "title": "Spring Blooms of Sea Ice Algae Along the Western Antarctic Peninsula: Effects of Warming and Freshening on Cell Physiology and Biogeochemical Cycles.", "uid": "p0010039", "west": -64.4}, {"awards": "1341479 Marchetti, Adrian", "bounds_geometry": "POLYGON((-72.8 -48,-67.12 -48,-61.44 -48,-55.76 -48,-50.08 -48,-44.4 -48,-38.72 -48,-33.04 -48,-27.36 -48,-21.68 -48,-16 -48,-16 -50.02,-16 -52.04,-16 -54.06,-16 -56.08,-16 -58.1,-16 -60.12,-16 -62.14,-16 -64.16,-16 -66.18,-16 -68.2,-21.68 -68.2,-27.36 -68.2,-33.04 -68.2,-38.72 -68.2,-44.4 -68.2,-50.08 -68.2,-55.76 -68.2,-61.44 -68.2,-67.12 -68.2,-72.8 -68.2,-72.8 -66.18,-72.8 -64.16,-72.8 -62.14,-72.8 -60.12,-72.8 -58.1,-72.8 -56.08,-72.8 -54.06,-72.8 -52.04,-72.8 -50.02,-72.8 -48))", "dataset_titles": "16S and 18S Sequence data; Fragilariopsis kerguelensis iron and light transcriptomes; Physiology and transcriptomes of polar isolates; Polar isolate transcriptomes; Sequence data from Ocean Station Papa seawater ; Sequence data RNA-Seq of marine phytoplankton: FeB12", "datasets": [{"dataset_uid": "200016", "doi": "", "keywords": null, "people": null, "repository": "iMicrobe", "science_program": null, "title": "Fragilariopsis kerguelensis iron and light transcriptomes", "url": "https://www.imicrobe.us/#/projects/104"}, {"dataset_uid": "200021", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "16S and 18S Sequence data", "url": "https://www.ncbi.nlm.nih.gov/bioproject/PRJNA299401"}, {"dataset_uid": "200020", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Physiology and transcriptomes of polar isolates", "url": "https://www.bco-dmo.org/project/653229"}, {"dataset_uid": "200019", "doi": "", "keywords": null, "people": null, "repository": "Cyverse Data Commons", "science_program": null, "title": "Polar isolate transcriptomes", "url": "http://datacommons.cyverse.org/search/?search_term=unc_phyto_isolates"}, {"dataset_uid": "200018", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "Sequence data from Ocean Station Papa seawater ", "url": "https://www.ncbi.nlm.nih.gov/sra/SRP006906"}, {"dataset_uid": "200017", "doi": "", "keywords": null, "people": null, "repository": "NCBI GenBank", "science_program": null, "title": "Sequence data RNA-Seq of marine phytoplankton: FeB12", "url": "https://www.ncbi.nlm.nih.gov/sra/SRP074366"}], "date_created": "Mon, 11 Mar 2019 00:00:00 GMT", "description": "The Southern Ocean surrounding Antarctica is changing rapidly in response to Earth\u0027s warming climate. These changes will undoubtedly influence communities of primary producers (the organisms at the base of the food chain, particularly plant-like organisms using sunlight for energy) by altering conditions that influence their growth and composition. Because primary producers such as phytoplankton play an important role in global biogeochemical cycling, it is essential to understand how they will respond to changes in their environment. The growth of phytoplankton in certain regions of the Southern Ocean is constrained by steep gradients in chemical and physical properties that vary in both space and time. Light and iron have been identified as key variables influencing phytoplankton abundance and distribution within Antarctic waters. Microscopic algae known as diatoms are dominant members of the phytoplankton and sea ice communities, accounting for significant proportions of primary production. The overall objective of this project is to identify the molecular bases for the physiological responses of polar diatoms to varying light and iron conditions. The project should provide a means of evaluating the extent these factors regulate diatom growth and influence net community productivity in Antarctic waters. The project will also further the NSF goals of making scientific discoveries available to the general public and of training new generations of scientists. It will facilitate the teaching and learning of polar-related topics by translating the research objectives into readily accessible educational materials for middle-school students. This project will also provide funding to enable a graduate student and several undergraduate students to be trained in the techniques and perspectives of modern biology. Although numerous studies have investigated how polar diatoms are affected by varying light and iron, the cellular mechanisms leading to their distinct physiological responses remain unknown. Using comparative transcriptomics, the expression patterns of key genes and metabolic pathways in several ecologically important polar diatoms recently isolated from Antarctic waters and grown under varying iron and irradiance conditions will be examined. In addition, molecular indicators for iron and light limitation will be developed within these polar diatoms through the identification of iron- and light-responsive genes -- the expression patterns of which can be used to determine their physiological status. Upon verification in laboratory cultures, these indicators will be utilized by way of metatranscriptomic sequencing to examine iron and light limitation in natural diatom assemblages collected along environmental gradients in Western Antarctic Peninsula waters. In order to fully understand the role phytoplankton play in Southern Ocean biogeochemical cycles, dependable methods that provide a means of elucidating the physiological status of phytoplankton at any given time and location are essential.", "east": -16.0, "geometry": "POINT(-44.4 -58.1)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "NOT APPLICABLE; AQUATIC SCIENCES; PHYTOPLANKTON; USAP-DC; Southern Ocean; Sea Surface; DIATOMS", "locations": "Sea Surface; Southern Ocean", "north": -48.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Marchetti, Adrian", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "iMicrobe", "repositories": "BCO-DMO; Cyverse Data Commons; iMicrobe; NCBI GenBank", "science_programs": null, "south": -68.2, "title": "Iron and Light Limitation in Ecologically Important Polar Diatoms: Comparative Transcriptomics and Development of Molecular Indicators", "uid": "p0010018", "west": -72.8}, {"awards": "1656344 Bowman, Jeff", "bounds_geometry": "POLYGON((-64.1 -64.75,-64.08 -64.75,-64.06 -64.75,-64.04 -64.75,-64.02 -64.75,-64 -64.75,-63.98 -64.75,-63.96 -64.75,-63.94 -64.75,-63.92 -64.75,-63.9 -64.75,-63.9 -64.775,-63.9 -64.8,-63.9 -64.825,-63.9 -64.85,-63.9 -64.875,-63.9 -64.9,-63.9 -64.925,-63.9 -64.95,-63.9 -64.975,-63.9 -65,-63.92 -65,-63.94 -65,-63.96 -65,-63.98 -65,-64 -65,-64.02 -65,-64.04 -65,-64.06 -65,-64.08 -65,-64.1 -65,-64.1 -64.975,-64.1 -64.95,-64.1 -64.925,-64.1 -64.9,-64.1 -64.875,-64.1 -64.85,-64.1 -64.825,-64.1 -64.8,-64.1 -64.775,-64.1 -64.75))", "dataset_titles": "\r\nMetadata accompanying BioProject SUB4579142 ; Western Antarctic Peninsula Marine Metatranscriptomes Sep 29 2018", "datasets": [{"dataset_uid": "601153", "doi": "", "keywords": "Antarctic; Antarctica; Bacteria; Bacteria Production; Biota; Chlorophyll; LTER Palmer Station; Primary Production; Sea Ice; Southern Ocean", "people": "Bowman, Jeff", "repository": "USAP-DC", "science_program": null, "title": "\r\nMetadata accompanying BioProject SUB4579142 ", "url": "https://www.usap-dc.org/view/dataset/601153"}, {"dataset_uid": "200010", "doi": "", "keywords": null, "people": null, "repository": "NCBI SRA", "science_program": null, "title": "Western Antarctic Peninsula Marine Metatranscriptomes Sep 29 2018", "url": "https://submit.ncbi.nlm.nih.gov/subs/sra/SUB4579142/overview"}], "date_created": "Thu, 31 Jan 2019 00:00:00 GMT", "description": "This EAGER project will compare gene expression patterns in the planktonic communities under ice covers that form in coastal embayment\u0027s in the Antarctic Peninsula. Previous efforts taking advantage of unique ice conditions in November and December of 2015 allowed researchers to conduct an experiment to examine the role of sea ice cover on microbial carbon and energy transfer during the winter-spring transition. The EAGER effort will enable the researchers to conduct the \"omics\" analyses of the phytoplankton to determine predominant means by which energy is acquired and used in these settings. This EAGER effort will apply new expertise to fill an existing gap in ecological observations along the West Antarctic Peninsula. The principle product of the proposed work will be a novel dataset to be analyzed and by an early career researcher from an underserved community (veteran). The critical baseline data contained in this dataset enable a comparison of eukaryotic and prokaryotic gene expression patterns to establish the relative importance of chemoautotrophy, heterotrophy, mixotrophy, and phototrophy during the experiments. this information and data will be made immediately available to the broader scientific community, and will enable the development of further hypotheses on ecosystem change as sea ice cover changes in the region. Very little gene expression data is currently available for the Antarctic marine environment, and no gene expression data is available during the ecologically critical winter to spring transition. Moreover, ice cover in bays is common along the West Antarctic Peninsula yet the opportunity to study cryptophyte phytoplankton physiology beneath such ice conditions in coastal embayments is rare.", "east": -63.9, "geometry": "POINT(-64 -64.875)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "USAP-DC; NOT APPLICABLE; Antarctica; COASTAL", "locations": "Antarctica", "north": -64.75, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Bowman, Jeff", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "USAP-DC", "repositories": "NCBI SRA; USAP-DC", "science_programs": null, "south": -65.0, "title": "A Preliminary Assessment of the Influence of Ice Cover on Microbial Carbon and Energy Acquisition during the Antarctic Winter-spring Seasonal Transition", "uid": "p0010003", "west": -64.1}, {"awards": "1341440 Jin, Meibing; 1341558 Ji, Rubao; 1341547 Stroeve, Julienne", "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": "Antarctic MIZ, Pack Ice and Polynya Maps from Passive Microwave Satellite Data; Ice-ocean-ecosystem model output; Sea ice chlorophyll concentrations in Antarctic coastal polynyas and seasonal ice zones", "datasets": [{"dataset_uid": "601136", "doi": "10.15784/601136", "keywords": "Antarctica; Biota; Model Data; Oceans; Southern Ocean", "people": "Jin, Meibing", "repository": "USAP-DC", "science_program": null, "title": "Ice-ocean-ecosystem model output", "url": "https://www.usap-dc.org/view/dataset/601136"}, {"dataset_uid": "601219", "doi": "10.15784/601219", "keywords": "Antarctica; Biota; Chlorophyll; Chlorophyll Concentration; Oceans; Polynya; Sea Ice Concentration; Seasonal Ice Zone; Southern Ocean", "people": "Ji, Rubao", "repository": "USAP-DC", "science_program": null, "title": "Sea ice chlorophyll concentrations in Antarctic coastal polynyas and seasonal ice zones", "url": "https://www.usap-dc.org/view/dataset/601219"}, {"dataset_uid": "601115", "doi": "10.15784/601115", "keywords": "Antarctica; Pack Ice; Polynya; Sea Ice; Southern Ocean", "people": "Stroeve, Julienne", "repository": "USAP-DC", "science_program": null, "title": "Antarctic MIZ, Pack Ice and Polynya Maps from Passive Microwave Satellite Data", "url": "https://www.usap-dc.org/view/dataset/601115"}], "date_created": "Tue, 20 Nov 2018 00:00:00 GMT", "description": "The aim of study is to understand how climate-related changes in snow and ice affect predator populations in the Antarctic, using the Ad\u00e9lie penguin as a focal species due to its long history as a Southern Ocean \u0027sentinel\u0027 species and the number of long-term research programs monitoring its abundance, distribution, and breeding biology. Understanding the environmental factors that control predator population dynamics is critically important for projecting the state of populations under future climate change scenarios, and for designing better conservation strategies for the Antarctic ecosystem. For the first time, datasets from a network of observational sites for the Ad\u00e9lie penguin across the entire Antarctic will be combined and analyzed, with a focus on linkages among the ice environment, primary production, and the population responses of Ad\u00e9lie penguins. The project will also further the NSF goals of making scientific discoveries available to the general public and of training new generations of scientists. The results of this project can be used to illustrate intuitively to the general public the complex interactions between ice, ocean, pelagic food web and top predators. This project also offers an excellent platform to demonstrate the process of climate-change science - how scientists simulate climate change scenarios and interpret model results. This project supports the training of undergraduate and graduate students in the fields of polar oceanography, plankton and seabird ecology, coupled physical-biological modeling and mathematical ecology. The results will be broadly disseminated to the general oceanographic research community through scientific workshops, conferences and peer-reviewed journal articles, and to undergraduate and graduate education communities, K-12 schools and organizations, and the interested public through web-based servers using existing infrastructure at the investigators\u0027 institutions. The key question to be addressed in this project is how climate impacts the timing of periodic biological events (phenology) and how interannual variation in this periodic forcing influences the abundance of penguins in the Antarctic. The focus will be on the timing of ice algae and phytoplankton blooms because the high seasonality of sea ice and associated pulsed primary productivity are major drivers of the Antarctic food web. This study will also examine the responses of Ad\u00e9lie penguins to changes in sea ice dynamics and ice algae-phytoplankton phenology. Ad\u00e9lie penguins, like many other Antarctic seabirds, are long-lived, upper trophic-level predators that integrate the effects of sea ice on the food web at regional scales, and thus serve as a reliable biological indicator of environmental changes. The proposed approach is designed to accommodate the limits of measuring and modeling the intermediate trophic levels between phytoplankton and penguins (e.g., zooplankton and fish) at the pan-Antarctic scale, which are important but latent variables in the Southern Ocean food web. Through the use of remotely sensed and in situ data, along with state of the art statistical approaches (e.g. wavelet analysis) and numerical modeling, this highly interdisciplinary study will advance our understanding of polar ecosystems and improve the projection of future climate change scenarios.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "USAP-DC; MARINE ECOSYSTEMS; NOT APPLICABLE; Antarctica", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Jin, Meibing; Stroeve, Julienne; Ji, Rubao", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Collaborative Research: Phytoplankton Phenology in the Antarctic: Drivers, Patterns, and Implications for the Adelie Penguin", "uid": "p0000001", "west": -180.0}, {"awards": "1103428 Thurber, Andrew", "bounds_geometry": "POLYGON((165 -77,165.5 -77,166 -77,166.5 -77,167 -77,167.5 -77,168 -77,168.5 -77,169 -77,169.5 -77,170 -77,170 -77.1,170 -77.2,170 -77.3,170 -77.4,170 -77.5,170 -77.6,170 -77.7,170 -77.8,170 -77.9,170 -78,169.5 -78,169 -78,168.5 -78,168 -78,167.5 -78,167 -78,166.5 -78,166 -78,165.5 -78,165 -78,165 -77.9,165 -77.8,165 -77.7,165 -77.6,165 -77.5,165 -77.4,165 -77.3,165 -77.2,165 -77.1,165 -77))", "dataset_titles": "McMurdo Spiophanes beds 16s V4 region community composition from sediment cores at McMurdo Station, Antarctia on Sept 9th, 2012 (McMurdo Benthos project); Stable isotopic composition of McMurdo Benthos", "datasets": [{"dataset_uid": "000202", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "McMurdo Spiophanes beds 16s V4 region community composition from sediment cores at McMurdo Station, Antarctia on Sept 9th, 2012 (McMurdo Benthos project)", "url": "https://www.bco-dmo.org/dataset/716443"}, {"dataset_uid": "000201", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Stable isotopic composition of McMurdo Benthos", "url": "https://www.bco-dmo.org/dataset/716462"}], "date_created": "Tue, 10 Oct 2017 00:00:00 GMT", "description": "The biota of the world\u0027s seafloor is fueled by bursts of seasonal primary production. For food-limited sediment communities to persist, a balance must exist between metazoan consumption of and competition with bacteria, a balance which likely changes through the seasons. Polar marine ecosystems are ideal places to study such complex interactions due to stark seasonal shifts between heterotrophic and autotrophic communities, and temperatures that may limit microbial processing of organic matter. The research will test the following hypotheses: 1) heterotrophic bacteria compete with macrofauna for food; 2) as phytoplankton populations decline macrofauna increasingly consume microbial biomass to sustain their populations; and 3) in the absence of seasonal photosynthetic inputs, macrofaunal biodiversity will decrease unless supplied with microbially derived nutrition. Observational and empirical studies will test these hypotheses at McMurdo Station, Antarctica, where a high-abundance macro-infaunal community is adapted to this boom-and-bust cycle of productivity. The investigator will mentor undergraduates from a predominantly minority-serving institution, in the fields of invertebrate taxonomy and biogeochemistry. The general public and young scientists will be engaged through lectures at local K-12 venues and launch of an interactive website. The results will better inform scientists and managers about the effects of climate change on polar ecosystems and the mechanisms of changing productivity patterns on global biodiversity.", "east": 170.0, "geometry": "POINT(167.5 -77.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -77.0, "nsf_funding_programs": null, "paleo_time": null, "persons": "Thurber, Andrew", "platforms": "Not provided", "repo": "BCO-DMO", "repositories": "BCO-DMO", "science_programs": null, "south": -78.0, "title": "PostDoctoral Research Fellowship", "uid": "p0000416", "west": 165.0}, {"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": "601108", "doi": "10.15784/601108", "keywords": "Antarctica; Biota; Glaciology", "people": "Webster, Donald R; Yen, Jeannette; Adhikari, Deepak", "repository": "USAP-DC", "science_program": null, "title": "Tomographic PIV measurements of swimming shelled Antarctic pteropod", "url": "https://www.usap-dc.org/view/dataset/601108"}, {"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"}], "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": "0944165 McGillicuddy, Dennis; 0944254 Smith, Walker", "bounds_geometry": "POLYGON((168 -65,168.2 -65,168.4 -65,168.6 -65,168.8 -65,169 -65,169.2 -65,169.4 -65,169.6 -65,169.8 -65,170 -65,170 -65,170 -65,170 -65,170 -65,170 -65,170 -65,170 -65,170 -65,170 -65,170 -65,169.8 -65,169.6 -65,169.4 -65,169.2 -65,169 -65,168.8 -65,168.6 -65,168.4 -65,168.2 -65,168 -65,168 -65,168 -65,168 -65,168 -65,168 -65,168 -65,168 -65,168 -65,168 -65,168 -65))", "dataset_titles": "Data from expdition NBP1201; Expedition Data; Project data: Processes Regulating Iron Supply at the Mesoscale - Ross Sea", "datasets": [{"dataset_uid": "000155", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Project data: Processes Regulating Iron Supply at the Mesoscale - Ross Sea", "url": "http://www.bco-dmo.org/project/2155"}, {"dataset_uid": "000156", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Data from expdition NBP1201", "url": "http://www.bco-dmo.org/deployment/506350"}, {"dataset_uid": "001442", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP1201"}], "date_created": "Wed, 08 Jul 2015 00:00:00 GMT", "description": "The Ross Sea continental shelf is one of the most productive areas in the Southern Ocean, and may comprise a significant, but unaccounted for, oceanic CO2 sink, largely driven by phytoplankton production. The processes that control the magnitude of primary production in this region are not well understood, but data suggest that iron limitation is a factor. Field observations and model simulations indicate four potential sources of dissolved iron to surface waters of the Ross Sea: (1) circumpolar deep water intruding from the shelf edge; (2) sediments on shallow banks and nearshore areas; (3) melting sea ice around the perimeter of the polynya; and (4) glacial meltwater from the Ross Ice Shelf. The principal investigators hypothesize that hydrodynamic transport via mesoscale currents, fronts, and eddies facilitate the supply of dissolved iron from these four sources to the surface waters of the Ross Sea polynya. These hypotheses will be tested through a combination of in situ observations and numerical modeling, complemented by satellite remote sensing. In situ observations will be obtained during a month-long cruise in the austral summer. The field data will be incorporated into model simulations, which allow quantification of the relative contributions of the various hypothesized iron supply mechanisms, and assessment of their impact on primary production. The research will provide new insights and a mechanistic understanding of the complex oceanographic phenomena that regulate iron supply, primary production, and biogeochemical cycling. The research will thus form the basis for predictions about how this system may change in a warming climate. The broader impacts include training of graduate and undergraduate students, international collaboration, and partnership with several ongoing outreach programs that address scientific research in the Southern Ocean. The research also will contribute to the goals of the international research programs ICED (Integrated Climate and Ecosystem Dynamics) and GEOTRACES (Biogeochemical cycling and trace elements in the marine environment).", "east": 170.0, "geometry": "POINT(169 -65)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e FLUOROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e PROFILERS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e XBT; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e ECHO SOUNDERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e MBES; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e THERMOSALINOGRAPHS", "is_usap_dc": true, "keywords": "R/V NBP; Not provided", "locations": null, "north": -65.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Walker; McGillicuddy, Dennis", "platforms": "Not provided; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "BCO-DMO", "repositories": "BCO-DMO; R2R", "science_programs": null, "south": -65.0, "title": "Collaborative Research: Impact of Mesoscale Processes on Iron Supply and Phytoplankton Dynamics in the Ross Sea", "uid": "p0000330", "west": 168.0}, {"awards": "9909367 Leventer, Amy", "bounds_geometry": "POLYGON((26.27227 -42.81742,38.414467 -42.81742,50.556664 -42.81742,62.698861 -42.81742,74.841058 -42.81742,86.983255 -42.81742,99.125452 -42.81742,111.267649 -42.81742,123.409846 -42.81742,135.552043 -42.81742,147.69424 -42.81742,147.69424 -45.454494,147.69424 -48.091568,147.69424 -50.728642,147.69424 -53.365716,147.69424 -56.00279,147.69424 -58.639864,147.69424 -61.276938,147.69424 -63.914012,147.69424 -66.551086,147.69424 -69.18816,135.552043 -69.18816,123.409846 -69.18816,111.267649 -69.18816,99.125452 -69.18816,86.983255 -69.18816,74.841058 -69.18816,62.698861 -69.18816,50.556664 -69.18816,38.414467 -69.18816,26.27227 -69.18816,26.27227 -66.551086,26.27227 -63.914012,26.27227 -61.276938,26.27227 -58.639864,26.27227 -56.00279,26.27227 -53.365716,26.27227 -50.728642,26.27227 -48.091568,26.27227 -45.454494,26.27227 -42.81742))", "dataset_titles": "Diatom assemblages from Edward VIII Gulf, Kemp Coast, East Antarctica; NB0101 Expedition Data; Quantitative Diatom Assemblage Data from Iceberg Alley, Mac. Robertson Shelf, East Antarctica acquired during expedition NBP0101", "datasets": [{"dataset_uid": "601177", "doi": "10.15784/601177", "keywords": "Antarctica; Biota; Diatom; East Antarctica; Microscopy; NBP0101; Oceans; Paleoceanography; Paleoclimate; R/v Nathaniel B. Palmer; Sediment Corer", "people": "Leventer, Amy", "repository": "USAP-DC", "science_program": null, "title": "Diatom assemblages from Edward VIII Gulf, Kemp Coast, East Antarctica", "url": "https://www.usap-dc.org/view/dataset/601177"}, {"dataset_uid": "601307", "doi": null, "keywords": "Antarctica; Biota; Diatom; East Antarctica; Mac. Robertson Shelf; Marine Geoscience; Microscope; NBP0101; Paleoclimate; Piston Corer; R/v Nathaniel B. Palmer; Sediment Core; Species Abundance", "people": "Leventer, Amy", "repository": "USAP-DC", "science_program": null, "title": "Quantitative Diatom Assemblage Data from Iceberg Alley, Mac. Robertson Shelf, East Antarctica acquired during expedition NBP0101", "url": "https://www.usap-dc.org/view/dataset/601307"}, {"dataset_uid": "001879", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "NB0101 Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0101"}], "date_created": "Thu, 03 Mar 2011 00:00:00 GMT", "description": "9909367 Leventer This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a multi-institutional, international (US - Australia) marine geologic and geophysical investigation of Prydz Bay and the MacRobertson Shelf, to be completed during an approximately 60-day cruise aboard the RVIB N.B. Palmer. The primary objective is to develop a record of climate and oceanographic change during the Quaternary, using sediment cores collected via kasten and jumbo piston coring. Core sites will be selected based on seismic profiling (Seabeam 2112 and Bathy2000). Recognition of the central role of the Antarctic Ice Sheet to global oceanic and atmospheric systems is based primarily on data collected along the West Antarctic margin, while similar extensive and high resolution data sets from the much more extensive East Antarctic margin are sparse. Goals of this project include (1) development of a century- to millennial-scale record of Holocene paleoenvironments, and (2) testing of hypotheses concerning the sedimentary record of previous glacial and interglacial events on the shelf, and evaluation of the timing and extent of maximum glaciation along this 500 km stretch of the East Antarctic margin. High-resolution seismic mapping and coring of sediments deposited in inner shelf depressions will be used to reconstruct Holocene paleoenvironments. In similar depositional settings in the Antarctic Peninsula and Ross Sea, sedimentary records demonstrate millennial- and century- scale variability in primary production and sea-ice extent during the Holocene, which have been linked to chronological periodicities in radiocarbon distribution, suggesting the possible role of solar variability in driving some changes in Holocene climate. Similar high-resolution Holocene records from the East Antarctic margin will be used to develop a circum-Antarctic suite of data regarding the response of southern glacial and oceanographic systems to late Quaternary climate change. In addition, these data will help us to evaluate the response of the East Antarctic margin to global warming. Initial surveys of the Prydz Channel - Amery Depression region reveal sequences deposited during previous Pleistocene interglacials. The upper Holocene and lower (undated) siliceous units can be traced over 15,000 km2 of the Prydz Channel, but more sub-bottom seismic reflection profiling in conjunction with dense coring over this region is needed to define the spatial distribution and extent of the units. Chronological work will determine the timing and duration of previous periods of glacial marine sedimentation on the East Antarctic margin during the late Pleistocene. Analyses will focus on detailed sedimentologic, geochemical, micropaleontological, and paleomagnetic techniques. This multi-parameter approach is the most effective way to extract a valuable paleoenvironmental signal in these glacial marine sediments. These results are expected to lead to a significant advance in understanding of the behavior of the Antarctic ice-sheet and ocean system in the recent geologic past. The combination of investigators, all with many years of experience working in high latitude marine settings, will provide an effective team to complete the project. University and College faculty (Principal Investigators on this project) will supervise a combination of undergraduate and post-graduate students involved in all stages of the project so that educational objectives will be met in tandem with the research goals of the project.", "east": 147.69424, "geometry": "POINT(86.983255 -56.00279)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e SEDIMENT CORERS", "is_usap_dc": false, "keywords": "R/V NBP; USAP-DC", "locations": null, "north": -42.81742, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Leventer, Amy", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "USAP-DC", "repositories": "R2R; USAP-DC", "science_programs": null, "south": -69.18816, "title": "Quaternary Glacial History and Paleoenvironments of the East Antarctic Margin", "uid": "p0000609", "west": 26.27227}, {"awards": "0732535 Arrigo, Kevin", "bounds_geometry": "POLYGON((-130 -67,-127.1 -67,-124.2 -67,-121.3 -67,-118.4 -67,-115.5 -67,-112.6 -67,-109.7 -67,-106.8 -67,-103.9 -67,-101 -67,-101 -67.9,-101 -68.8,-101 -69.7,-101 -70.6,-101 -71.5,-101 -72.4,-101 -73.3,-101 -74.2,-101 -75.1,-101 -76,-103.9 -76,-106.8 -76,-109.7 -76,-112.6 -76,-115.5 -76,-118.4 -76,-121.3 -76,-124.2 -76,-127.1 -76,-130 -76,-130 -75.1,-130 -74.2,-130 -73.3,-130 -72.4,-130 -71.5,-130 -70.6,-130 -69.7,-130 -68.8,-130 -67.9,-130 -67))", "dataset_titles": "GEOTRACES International Data Assembly Centre Accession# NIO100280", "datasets": [{"dataset_uid": "000212", "doi": "", "keywords": null, "people": null, "repository": "GEOTRACES", "science_program": null, "title": "GEOTRACES International Data Assembly Centre Accession# NIO100280", "url": "http://www.bodc.ac.uk/geotraces/"}], "date_created": "Thu, 24 Feb 2011 00:00:00 GMT", "description": "IPY: Shedding dynamic light on iron limitation: The interplay of iron\u003cbr/\u003elimitation and dynamic irradiance in governing the phytoplankton\u003cbr/\u003edistribution in the Ross Sea\u003cbr/\u003e\u003cbr/\u003eThe Southern Ocean plays an important role in the global carbon cycle, accounting for approximately 25% of total anthropogenic CO2 uptake by the oceans, mainly via primary production. In the Ross Sea, primary production is dominated by two taxa that are distinct in location and timing. Diatoms dominate in the shallow mixed layer of the continental shelf, whereas the colony forming Phaeocystis antarctica (Prymnesiophyceae) dominate in the more deeply mixed, open regions. Significantly, both groups have vastly different nutrient utilization characteristics, and support very different marine food webs. Their responses to climate change, and the implications for carbon export, are unclear. Previous studies show that light availability and the quality of the light climate (static versus dynamic) play a major role in defining where and when the different phytoplankton taxa bloom. However, iron (Fe) limitation of the algal communities in both the sub-Arctic and the Southern Ocean is now well documented. Moreover, phytoplankton Fe demand varies as a function of irradiance. The main hypothesis of the proposed research is: The interaction between Fe limitation and dynamic irradiance governs phytoplankton distributions in the Ross Sea. Our strategy to test this hypothesis is three-fold: 1) The photoacclimation of the different phytoplankton taxa to different light conditions under Fe limitation will be investigated in experiments in the laboratory under controlled Fe conditions. 2) The photophysiological mechanisms found in these laboratory experiments will then be tested in the field on two cruises with international IPY partners. 3) Finally, data generated during the lab and field parts of the project will be used to parameterize a dynamic light component of the Coupled Ice Atmosphere and Ocean (CIAO) model of the Ross Sea. Using the improved model, we will run future climate scenarios to test the impact of climate change on the phytoplankton community structure, distribution, primary production and carbon export in the Southern Ocean. The proposed research complies with IPY theme\" Understanding Environmental change in Polar Regions\" and includes participation in an international cruise. Detailed model descriptions and all of the results generated from these studies will be made public via a DynaLiFe website. Improving the CIAO model will give us and other IPY partners the opportunity to test the ecological consequences of physiological characteristics observed in Antarctic phytoplankton under current and future climate scenarios. Outreach will include participation in Stanford\u0027s Summer Program for Professional Development for Science Teachers, Stanford\u0027s School of Earth Sciences high school internship program, and development of curriculum for local science training centers, including the Chabot Space and Science Center.", "east": -101.0, "geometry": "POINT(-115.5 -71.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -67.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Arrigo, Kevin", "platforms": "Not provided", "repo": "GEOTRACES", "repositories": "GEOTRACES", "science_programs": null, "south": -76.0, "title": "IPY: Shedding dynamic light on iron limitation: The interplay of iron limitation and dynamic irradiance in governing the phytoplankton distribution in the Ross Sea", "uid": "p0000112", "west": -130.0}, {"awards": "0636723 Helly, John; 0636543 Murray, Alison; 0636440 Long, David; 0636319 Shaw, Timothy", "bounds_geometry": "POLYGON((-55 -52,-53.5 -52,-52 -52,-50.5 -52,-49 -52,-47.5 -52,-46 -52,-44.5 -52,-43 -52,-41.5 -52,-40 -52,-40 -53.3,-40 -54.6,-40 -55.9,-40 -57.2,-40 -58.5,-40 -59.8,-40 -61.1,-40 -62.4,-40 -63.7,-40 -65,-41.5 -65,-43 -65,-44.5 -65,-46 -65,-47.5 -65,-49 -65,-50.5 -65,-52 -65,-53.5 -65,-55 -65,-55 -63.7,-55 -62.4,-55 -61.1,-55 -59.8,-55 -58.5,-55 -57.2,-55 -55.9,-55 -54.6,-55 -53.3,-55 -52))", "dataset_titles": "Antarctic Iceberg Tracking Database; Free-Drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean; Free Drifting Icebergs as Proliferation Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "datasets": [{"dataset_uid": "600064", "doi": "10.15784/600064", "keywords": "Biota; Chemistry:fluid; Chemistry:Fluid; Geochemistry; Oceans; Sea Ice; Sea Surface; Southern Ocean; Weddell Sea", "people": "Shaw, Tim; Twining, Benjamin", "repository": "USAP-DC", "science_program": null, "title": "Free Drifting Icebergs as Proliferation Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "url": "https://www.usap-dc.org/view/dataset/600064"}, {"dataset_uid": "000134", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Antarctic Iceberg Tracking Database", "url": "http://www.scp.byu.edu/data/iceberg/database1.html"}, {"dataset_uid": "600067", "doi": "10.15784/600067", "keywords": "Antarctica; NBP0902; Oceans; Physical Oceanography; Southern Ocean; Weddell Sea", "people": "Helly, John", "repository": "USAP-DC", "science_program": null, "title": "Free-Drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "url": "https://www.usap-dc.org/view/dataset/600067"}, {"dataset_uid": "600065", "doi": "10.15784/600065", "keywords": "Biota; Geochemistry; NBP0902; Oceans; Physical Oceanography; Sea Ice; Southern Ocean; Weddell Sea", "people": "Murray, Alison", "repository": "USAP-DC", "science_program": null, "title": "Free-Drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "url": "https://www.usap-dc.org/view/dataset/600065"}], "date_created": "Mon, 22 Nov 2010 00:00:00 GMT", "description": "Atmospheric warming has been associated with retreating glaciers, disintegrating ice shelves, and the increasing prevalence of icebergs in the Southern Ocean over the last decade. Our preliminary study of two icebergs in the NW Weddell Sea, an area of high iceberg concentration, showed significant delivery of terrestrial material accompanied by significant enhancement of phytoplankton and zooplankton/micronekton abundance, and primary production surrounding the icebergs. We hypothesize that nutrient enrichment by free-drifting icebergs will increase primary production and sedimentation of organic carbon, thus increasing the draw-down and sequestration of CO2 in the Southern Ocean and impacting the global carbon cycle. Our research addresses the following questions:1) What is the relationship between the physical dynamics of free-drifting icebergs and the Fe and nutrient distributions of the surrounding water column? 2) What is the relationship between Fe and nutrient distributions associated with free-drifting icebergs and the organic carbon dynamics of the ice-attached and surrounding pelagic communities (microbes, zooplankton, micronekton)? 3) What is impact on the export flux of particulate organic carbon from the mixed layer? An interdisciplinary approach is proposed to examine iceberg structure and dynamics, biogeochemical processes, and carbon cycling that includes measurement of trace element, nutrient and radionuclide distributions; organic carbon dynamics mediated by microbial, ice-attached and zooplankton communities; and particulate organic carbon export fluxes. Results from this project will further our understanding of the relationship between climate change and carbon sequestration in the Southern Ocean. Our findings will be incorporated into the Antarctic Research division of the Ocean Exploration Center (OEC) as part of the SIOExplorer: Digital Library Project. The OEC allows users to access content, which is classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. Graduate students, undergraduates, teachers, and volunteers are important participants in the proposed field and laboratory work. For the K-12 level, a professional writer of children\u0027s books will participate in cruises to produce an account of the expedition and a daily interactive website.", "east": -40.0, "geometry": "POINT(-47.5 -58.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -52.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Twining, Benjamin; Shaw, Tim; Long, David; Murray, Alison; Helly, John", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "PI website; USAP-DC", "science_programs": null, "south": -65.0, "title": "Collaborative Research: Free Drifting Icebergs as Proliferation Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "uid": "p0000511", "west": -55.0}, {"awards": "0636730 Vernet, Maria", "bounds_geometry": "POLYGON((-55 -52,-53.5 -52,-52 -52,-50.5 -52,-49 -52,-47.5 -52,-46 -52,-44.5 -52,-43 -52,-41.5 -52,-40 -52,-40 -53.3,-40 -54.6,-40 -55.9,-40 -57.2,-40 -58.5,-40 -59.8,-40 -61.1,-40 -62.4,-40 -63.7,-40 -65,-41.5 -65,-43 -65,-44.5 -65,-46 -65,-47.5 -65,-49 -65,-50.5 -65,-52 -65,-53.5 -65,-55 -65,-55 -63.7,-55 -62.4,-55 -61.1,-55 -59.8,-55 -58.5,-55 -57.2,-55 -55.9,-55 -54.6,-55 -53.3,-55 -52))", "dataset_titles": "Free-drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "datasets": [{"dataset_uid": "600068", "doi": "10.15784/600068", "keywords": "Antarctica; Biota; Chemistry:fluid; Chemistry:Fluid; Geochemistry; NBP0902; Oceans; Physical Oceanography; Sea Surface; Southern Ocean; Weddell Sea", "people": "Vernet, Maria", "repository": "USAP-DC", "science_program": null, "title": "Free-drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean", "url": "https://www.usap-dc.org/view/dataset/600068"}], "date_created": "Mon, 22 Nov 2010 00:00:00 GMT", "description": "Atmospheric warming has been associated with retreating glaciers, disintegrating ice shelves, and the increasing prevalence of icebergs in the Southern Ocean over the last decade. Our preliminary study of two icebergs in the NW Weddell Sea, an area of high iceberg concentration, showed significant delivery of terrestrial material accompanied by significant enhancement of phytoplankton and zooplankton/micronekton abundance, and primary production surrounding the icebergs. We hypothesize that nutrient enrichment by free-drifting icebergs will increase primary production and sedimentation of organic carbon, thus increasing the draw-down and sequestration of CO2 in the Southern Ocean and impacting the global carbon cycle. Our research addresses the following questions:1) What is the relationship between the physical dynamics of free-drifting icebergs and the Fe and nutrient distributions of the surrounding water column? 2) What is the relationship between Fe and nutrient distributions associated with free-drifting icebergs and the organic carbon dynamics of the ice-attached and surrounding pelagic communities (microbes, zooplankton, micronekton)? 3) What is impact on the export flux of particulate organic carbon from the mixed layer? An interdisciplinary approach is proposed to examine iceberg structure and dynamics, biogeochemical processes, and carbon cycling that includes measurement of trace element, nutrient and radionuclide distributions; organic carbon dynamics mediated by microbial, ice-attached and zooplankton communities; and particulate organic carbon export fluxes. Results from this project will further our understanding of the relationship between climate change and carbon sequestration in the Southern Ocean. Our findings will be incorporated into the Antarctic Research division of the Ocean Exploration Center (OEC) as part of the SIOExplorer: Digital Library Project. The OEC allows users to access content, which is classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. Graduate students, undergraduates, teachers, and volunteers are important participants in the proposed field and laboratory work. For the K-12 level, a professional writer of children\u0027s books will participate in cruises to produce an account of the expedition and a daily interactive website.", "east": -40.0, "geometry": "POINT(-47.5 -58.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -52.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Vernet, Maria", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -65.0, "title": "Collaborative Reseach: Free-drifting Icebergs as Proliferating Dispersion Sites of Iron Enrichment, Organic Carbon Production and Export in the Southern Ocean.", "uid": "p0000532", "west": -55.0}, {"awards": "9727077 Smith, Kenneth", "bounds_geometry": "POLYGON((-70.907166 -52.348,-69.6496994 -52.348,-68.3922328 -52.348,-67.1347662 -52.348,-65.8772996 -52.348,-64.619833 -52.348,-63.3623664 -52.348,-62.1048998 -52.348,-60.8474332 -52.348,-59.5899666 -52.348,-58.3325 -52.348,-58.3325 -53.600917,-58.3325 -54.853834,-58.3325 -56.106751,-58.3325 -57.359668,-58.3325 -58.612585,-58.3325 -59.865502,-58.3325 -61.118419,-58.3325 -62.371336,-58.3325 -63.624253,-58.3325 -64.87717,-59.5899666 -64.87717,-60.8474332 -64.87717,-62.1048998 -64.87717,-63.3623664 -64.87717,-64.619833 -64.87717,-65.8772996 -64.87717,-67.1347662 -64.87717,-68.3922328 -64.87717,-69.6496994 -64.87717,-70.907166 -64.87717,-70.907166 -63.624253,-70.907166 -62.371336,-70.907166 -61.118419,-70.907166 -59.865502,-70.907166 -58.612585,-70.907166 -57.359668,-70.907166 -56.106751,-70.907166 -54.853834,-70.907166 -53.600917,-70.907166 -52.348))", "dataset_titles": "Expedition Data; Expedition data of LMG0002; Expedition data of LMG0005", "datasets": [{"dataset_uid": "002670", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG0002", "url": "https://www.rvdata.us/search/cruise/LMG0002"}, {"dataset_uid": "001964", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0010"}, {"dataset_uid": "002667", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG0005", "url": "https://www.rvdata.us/search/cruise/LMG0005"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "9727077 SMITH The annual expansion and contraction of ice cover in the Southern Ocean is the largest seasonal process in the World Ocean. This seasonal variability in ice cover creates extensive fluctuations in primary production, which heavily impacts pelagic and benthic communities. This research will initiate a long time-series study of the water column and sea floor using long-term, autonomous monitoring and sampling systems developed for use in the Antarctic. The study will be located in Post Foster, Deception Island, which supports a pelagic and benthic fauna representative of the Antarctic coastal zone and experiences seasonal ice cover. A bottom-moored, upward-looking acoustic instrument will be deployed on the sea floor for a period of one year to monitor the vertical distribution, abundance and biomass of acoustically-detectable macrozooplankton and micronekton in the water column. Collections will be made over this period using a newly-developed vertically-profiling pump sampling. Simultaneously, a time-lapse camera system will be moored on the sea floor to monitor the spatial distribution, sizes and movements of the epibenthic megafauna component of the benthic community. The instrumentation development will allow the research project to focus on the effect of the seasonal sea ice cycle on the distribution, abundance and biomass of the macrozooplankton and micronekton in the water column. Similar questions on the distribution, abundance, size and movements of the epibenthic megafauna will be addressed. Results from this study will provide a valuable data base for the evaluation of the pelagic and benthic community responses to seasonal variability in the Southern Ocean.", "east": -58.3325, "geometry": "POINT(-64.619833 -58.612585)", "instruments": null, "is_usap_dc": false, "keywords": "R/V LMG", "locations": null, "north": -52.348, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Kenneth", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -64.87717, "title": "Influence of Seasonal Ice Cover on Pelagic and Benthic Communities: Long Time-Series Studies", "uid": "p0000608", "west": -70.907166}, {"awards": "0529815 Smith, Kenneth", "bounds_geometry": "POLYGON((-68.12004 -52.65918,-65.348168 -52.65918,-62.576296 -52.65918,-59.804424 -52.65918,-57.032552 -52.65918,-54.26068 -52.65918,-51.488808 -52.65918,-48.716936 -52.65918,-45.945064 -52.65918,-43.173192 -52.65918,-40.40132 -52.65918,-40.40132 -53.972709,-40.40132 -55.286238,-40.40132 -56.599767,-40.40132 -57.913296,-40.40132 -59.226825,-40.40132 -60.540354,-40.40132 -61.853883,-40.40132 -63.167412,-40.40132 -64.480941,-40.40132 -65.79447,-43.173192 -65.79447,-45.945064 -65.79447,-48.716936 -65.79447,-51.488808 -65.79447,-54.26068 -65.79447,-57.032552 -65.79447,-59.804424 -65.79447,-62.576296 -65.79447,-65.348168 -65.79447,-68.12004 -65.79447,-68.12004 -64.480941,-68.12004 -63.167412,-68.12004 -61.853883,-68.12004 -60.540354,-68.12004 -59.226825,-68.12004 -57.913296,-68.12004 -56.599767,-68.12004 -55.286238,-68.12004 -53.972709,-68.12004 -52.65918))", "dataset_titles": "Expedition Data; Expedition data of LMG0514A", "datasets": [{"dataset_uid": "002668", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG0514A", "url": "https://www.rvdata.us/search/cruise/LMG0514A"}, {"dataset_uid": "001484", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0902"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "This project seeks to examine the importance of icebergs to the pelagic ecosystem of the North-West Weddell Sea. Atmospheric warming has been associated with retreating glaciers and the increasing prevalence of icebergs in the Southern Ocean over the last decade. The highest concentration of icebergs occurs in the NW Weddell Sea, where they drift in a clockwise pattern to the northeast, following the contours of the Antarctic Peninsula through an area dubbed \"Iceberg Alley\". Little is known about the impact of free-drifting icebergs on the pelagic ecosystem of the Weddell Sea or on the Southern Ocean as a whole. It is hypothesized that as drifting islands, icebergs of small to intermediate size (\u003c 10 km in largest dimension) impart unique physical, chemical and biological characteristics to the surrounding water. Three general questions will be asked to address this hypothesis: 1) What are the dynamics (approximate size, abundance and spatial distribution) of free-drifting icebergs on temporal scales of days to months, based on correlation of field measurements with imagery derived from satellite sensors? 2) What is the relationship between the size of free-drifting icebergs and the structure of the associated pelagic communities? 3) What is the estimated combined impact of free-drifting icebergs in the NW Weddell Sea on the biological characteristics of the pelagic zone? This interdisciplinary study will use standard oceanographic sampling coupled with unique methodology for staging shipboard data from all types of sensors and survey methods to determine the sphere of influence for a diverse set of biological factors as a function of iceberg size. The exploratory research proposed here will provide critical data on the effects of atmospheric warming in the Antarctic Peninsula region. The recent prevalence of free drifting icebergs in the Southern Ocean should have a pronounced enrichment effect on the surrounding pelagic ecosystem, altering community dynamics. Enhanced primary production associated with these icebergs could influence the global carbon cycle since the Southern Ocean is considered a major sink for excess CO2 from the atmosphere. \u003cbr/\u003eThe proposed research will include an innovative education component through the Ocean Exploration Center (OEC), whose focus is to provide a comprehensive view of the oceans, intelligible to non-scientists and researchers alike, with direct access to state-of-the-art databases and selected websites. The OEC will allow users to access content which has been classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. The results from this iceberg project will be incorporated into the Antarctic Research division of the OEC, providing databases documenting the impact of free-drifting icebergs on the surrounding pelagic ecosystem. These data then will be extrapolated to evaluate the impact of icebergs on the ecosystem of the Weddell Sea. Graduate students, undergraduates, teachers and volunteers are an important part of the proposed field and laboratory work.", "east": -40.40132, "geometry": "POINT(-54.26068 -59.226825)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e PRESSURE/HEIGHT METERS \u003e PRESSURE SENSORS; 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 CTD; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS; 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", "is_usap_dc": false, "keywords": "R/V LMG; R/V NBP", "locations": null, "north": -52.65918, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Ken", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -65.79447, "title": "Free Drifting Icebergs: Influence of Floating Islands on Pelagic Ecosystems in the Weddell Sea.", "uid": "p0000551", "west": -68.12004}, {"awards": "9909933 Ross, Robin; 9910175 Vernet, Maria", "bounds_geometry": "POLYGON((-71.077 -57.9543,-70.015 -57.9543,-68.953 -57.9543,-67.891 -57.9543,-66.829 -57.9543,-65.767 -57.9543,-64.705 -57.9543,-63.643 -57.9543,-62.581 -57.9543,-61.519 -57.9543,-60.457 -57.9543,-60.457 -58.98629,-60.457 -60.01828,-60.457 -61.05027,-60.457 -62.08226,-60.457 -63.11425,-60.457 -64.14624,-60.457 -65.17823,-60.457 -66.21022,-60.457 -67.24221,-60.457 -68.2742,-61.519 -68.2742,-62.581 -68.2742,-63.643 -68.2742,-64.705 -68.2742,-65.767 -68.2742,-66.829 -68.2742,-67.891 -68.2742,-68.953 -68.2742,-70.015 -68.2742,-71.077 -68.2742,-71.077 -67.24221,-71.077 -66.21022,-71.077 -65.17823,-71.077 -64.14624,-71.077 -63.11425,-71.077 -62.08226,-71.077 -61.05027,-71.077 -60.01828,-71.077 -58.98629,-71.077 -57.9543))", "dataset_titles": "Expedition Data; Expedition data of LMG0205; Expedition data of NBP0104; Expedition data of NBP0202; Expedition data of NBP0204", "datasets": [{"dataset_uid": "001861", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0106"}, {"dataset_uid": "002657", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0104", "url": "https://www.rvdata.us/search/cruise/NBP0104"}, {"dataset_uid": "002704", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG0205", "url": "https://www.rvdata.us/search/cruise/LMG0205"}, {"dataset_uid": "002586", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0202", "url": "https://www.rvdata.us/search/cruise/NBP0202"}, {"dataset_uid": "002643", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0204", "url": "https://www.rvdata.us/search/cruise/NBP0204"}, {"dataset_uid": "001856", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0105"}, {"dataset_uid": "001757", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0205"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "The U.S. Global Ocean Ecosystems Dynamics (U.S. GLOBEC) program has the goal of understanding and ultimately predicting how populations of marine animal species respond to natural and anthropogenic changes in climate. Research in the Southern Ocean (SO) indicates strong coupling between climatic processes and ecosystem dynamics via the annual formation and destruction of sea ice. The Southern Ocean GLOBEC Program (SO GLOBEC) will investigate the dynamic relationship between physical processes and ecosystem responses through identification of critical parameters that affect the distribution, abundance and population dynamics of target species. The overall goals of the SO GLOBEC program are to elucidate shelf circulation processes and their effect on sea ice formation and krill distribution, and to examine the factors which govern krill survivorship and availability to higher trophic levels, including penguins, seals and whales. The focus of the U.S. contribution to the international SO GLOBEC program will be on winter processes. This component will focus on water-column primary production using direct experimental estimates, modeling restuls from a fast repetition rate fluorometer and modeling of primary production from both optical as well as biophysical models. This research will be coordinated with components focused on sea ice production and sea ice habitat. The result of the integrated SO GLOBEC program will be to improve the predictability of living marine resources, especially with respect to local and global climatic shifts.", "east": -60.457, "geometry": "POINT(-65.767 -63.11425)", "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 LMG; R/V NBP", "locations": null, "north": -57.9543, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Vernet, Maria; Costa, Daniel; Ross, Robin Macurda; Smith, Raymond", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -68.2742, "title": "GLOBEC: Winter Ecology of Larval Krill: Quantifying their Interaction with the Pack Ice Habitat", "uid": "p0000605", "west": -71.077}, {"awards": "9816049 DeMaster, David", "bounds_geometry": "POLYGON((-70.90654 -52.35368,-70.220384 -52.35368,-69.534228 -52.35368,-68.848072 -52.35368,-68.161916 -52.35368,-67.47576 -52.35368,-66.789604 -52.35368,-66.103448 -52.35368,-65.417292 -52.35368,-64.731136 -52.35368,-64.04498 -52.35368,-64.04498 -53.639401,-64.04498 -54.925122,-64.04498 -56.210843,-64.04498 -57.496564,-64.04498 -58.782285,-64.04498 -60.068006,-64.04498 -61.353727,-64.04498 -62.639448,-64.04498 -63.925169,-64.04498 -65.21089,-64.731136 -65.21089,-65.417292 -65.21089,-66.103448 -65.21089,-66.789604 -65.21089,-67.47576 -65.21089,-68.161916 -65.21089,-68.848072 -65.21089,-69.534228 -65.21089,-70.220384 -65.21089,-70.90654 -65.21089,-70.90654 -63.925169,-70.90654 -62.639448,-70.90654 -61.353727,-70.90654 -60.068006,-70.90654 -58.782285,-70.90654 -57.496564,-70.90654 -56.210843,-70.90654 -54.925122,-70.90654 -53.639401,-70.90654 -52.35368))", "dataset_titles": "Expedition Data; Expedition data of LMG0003", "datasets": [{"dataset_uid": "001983", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0004"}, {"dataset_uid": "002690", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG0003", "url": "https://www.rvdata.us/search/cruise/LMG0003"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "OPP98-15823 P.I. Craig Smith\u003cbr/\u003eOPP98-16049 P.I. David DeMaster\u003cbr/\u003e\u003cbr/\u003ePrimary production in Antarctic coastal waters is highly seasonal, yielding an intense pulse of biogenic particles to the continental shelf floor. This seasonal pulse may have major ramifications for carbon cycling, benthic ecology and material burial on the west Antarctic Peninsula (WAP) shelf. Thus, we propose a multii-disciplinary program to evaluate the seafloor accumulation, fate and benthic community impacts of bloom material along a transect of three stations crossing the Antarctic shelf in the Palmer LTER study area. Using a seasonal series of five cruises to our transect, we will test the following hypostheses: (1) A substantial proportion of spring/summer export production is deposited ont eh WAP shelf as phytodetritus or fecal pellets. (2) The deposited bloom production is a source of labile particulate organic carbon for benthos for an extended period of time (months). (3) Large amounts of labile bloom POC are rapidly subducted into the sediment column by the deposit-feeding and caching activities of benthos. (4) Macrobenthic detritivores sustain a rapid increase in biomass and abundance following the spring/summer particulate organic carbon pulse. To test these hypotheses, we will evaluate seabed deposition and lability of particulate organic carbon, patterns of particulate organic carbon mixing into sediments, seasonal variations in macrofaunal and megafaunal abundance, biomass and reproductive condition, and rates of particulate organic carbon and silica mineralization and accumulation in the seabed. Fluxes of biogenic materials and radionuclides into midwater particle traps will be contrasted with seabed deposition and burial rates to establish water-column and seabed preservation efficiencies for these materials. The project will substantially improve our understanding of the spring/summer production pulse on the WAP shelf and its impacts on seafloor communities and carbon cycling in Antarctic coastal systems.", "east": -64.04498, "geometry": "POINT(-67.47576 -58.782285)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS", "is_usap_dc": false, "keywords": "R/V NBP; R/V LMG", "locations": null, "north": -52.35368, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "DeMaster, David; Smith, Craig", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -65.21089, "title": "Collaborative Research: Bentho-Pelagic Coupling on the West Antarctic Peninsula Shelf: The Impact and Fate of Bloom Material at the Seafloor", "uid": "p0000618", "west": -70.90654}, {"awards": "0650034 Smith, Kenneth", "bounds_geometry": null, "dataset_titles": "Expedition Data; Expedition data of NBP0806; Expedition data of NBP0902", "datasets": [{"dataset_uid": "001484", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0902"}, {"dataset_uid": "002649", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0806", "url": "https://www.rvdata.us/search/cruise/NBP0806"}, {"dataset_uid": "002650", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0902", "url": "https://www.rvdata.us/search/cruise/NBP0902"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "This project seeks to examine the importance of icebergs to the pelagic ecosystem of the North-West Weddell Sea. Atmospheric warming has been associated with retreating glaciers and the increasing prevalence of icebergs in the Southern Ocean over the last decade. The highest concentration of icebergs occurs in the NW Weddell Sea, where they drift in a clockwise pattern to the northeast, following the contours of the Antarctic Peninsula through an area dubbed \"Iceberg Alley\". Little is known about the impact of free-drifting icebergs on the pelagic ecosystem of the Weddell Sea or on the Southern Ocean as a whole. It is hypothesized that as drifting islands, icebergs of small to intermediate size (\u003c 10 km in largest dimension) impart unique physical, chemical and biological characteristics to the surrounding water. Three general questions will be asked to address this hypothesis: 1) What are the dynamics (approximate size, abundance and spatial distribution) of free-drifting icebergs on temporal scales of days to months, based on correlation of field measurements with imagery derived from satellite sensors? 2) What is the relationship between the size of free-drifting icebergs and the structure of the associated pelagic communities? 3) What is the estimated combined impact of free-drifting icebergs in the NW Weddell Sea on the biological characteristics of the pelagic zone? This interdisciplinary study will use standard oceanographic sampling coupled with unique methodology for staging shipboard data from all types of sensors and survey methods to determine the sphere of influence for a diverse set of biological factors as a function of iceberg size. The exploratory research proposed here will provide critical data on the effects of atmospheric warming in the Antarctic Peninsula region. The recent prevalence of free drifting icebergs in the Southern Ocean should have a pronounced enrichment effect on the surrounding pelagic ecosystem, altering community dynamics. Enhanced primary production associated with these icebergs could influence the global carbon cycle since the Southern Ocean is considered a major sink for excess CO2 from the atmosphere. \u003cbr/\u003eThe proposed research will include an innovative education component through the Ocean Exploration Center (OEC), whose focus is to provide a comprehensive view of the oceans, intelligible to non-scientists and researchers alike, with direct access to state-of-the-art databases and selected websites. The OEC will allow users to access content which has been classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. The results from this iceberg project will be incorporated into the Antarctic Research division of the OEC, providing databases documenting the impact of free-drifting icebergs on the surrounding pelagic ecosystem. These data then will be extrapolated to evaluate the impact of icebergs on the ecosystem of the Weddell Sea. Graduate students, undergraduates, teachers and volunteers are an important part of the proposed field and laboratory work.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS; 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", "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Ken", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Free Drifting Icebergs: Influence of Floating Islands on Pelagic Ecosystems in the Weddell Sea.", "uid": "p0000840", "west": null}, {"awards": "9815823 Smith, Craig", "bounds_geometry": "POLYGON((-70.90683 -52.35533,-69.8661302 -52.35533,-68.8254304 -52.35533,-67.7847306 -52.35533,-66.7440308 -52.35533,-65.703331 -52.35533,-64.6626312 -52.35533,-63.6219314 -52.35533,-62.5812316 -52.35533,-61.5405318 -52.35533,-60.499832 -52.35533,-60.499832 -53.818664,-60.499832 -55.281998,-60.499832 -56.745332,-60.499832 -58.208666,-60.499832 -59.672,-60.499832 -61.135334,-60.499832 -62.598668,-60.499832 -64.062002,-60.499832 -65.525336,-60.499832 -66.98867,-61.5405318 -66.98867,-62.5812316 -66.98867,-63.6219314 -66.98867,-64.6626312 -66.98867,-65.703331 -66.98867,-66.7440308 -66.98867,-67.7847306 -66.98867,-68.8254304 -66.98867,-69.8661302 -66.98867,-70.90683 -66.98867,-70.90683 -65.525336,-70.90683 -64.062002,-70.90683 -62.598668,-70.90683 -61.135334,-70.90683 -59.672,-70.90683 -58.208666,-70.90683 -56.745332,-70.90683 -55.281998,-70.90683 -53.818664,-70.90683 -52.35533))", "dataset_titles": "Expedition Data; Expedition data of LMG0009", "datasets": [{"dataset_uid": "002689", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG0009", "url": "https://www.rvdata.us/search/cruise/LMG0009"}, {"dataset_uid": "001880", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0102"}, {"dataset_uid": "001983", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP0004"}, {"dataset_uid": "001811", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0009"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "OPP98-15823 P.I. Craig Smith OPP98-16049 P.I. David DeMaster Primary production in Antarctic coastal waters is highly seasonal, yielding an intense pulse of biogenic particles to the continental shelf floor. This seasonal pulse may have major ramifications for carbon cycling, benthic ecology and material burial on the west Antarctic Peninsula (WAP) shelf. Thus, we propose a multii-disciplinary program to evaluate the seafloor accumulation, fate and benthic community impacts of bloom material along a transect of three stations crossing the Antarctic shelf in the Palmer LTER study area. Using a seasonal series of five cruises to our transect, we will test the following hypostheses: (1) A substantial proportion of spring/summer export production is deposited ont eh WAP shelf as phytodetritus or fecal pellets. (2) The deposited bloom production is a source of labile particulate organic carbon for benthos for an extended period of time (months). (3) Large amounts of labile bloom POC are rapidly subducted into the sediment column by the deposit-feeding and caching activities of benthos. (4) Macrobenthic detritivores sustain a rapid increase in biomass and abundance following the spring/summer particulate organic carbon pulse. To test these hypotheses, we will evaluate seabed deposition and lability of particulate organic carbon, patterns of particulate organic carbon mixing into sediments, seasonal variations in macrofaunal and megafaunal abundance, biomass and reproductive condition, and rates of particulate organic carbon and silica mineralization and accumulation in the seabed. Fluxes of biogenic materials and radionuclides into midwater particle traps will be contrasted with seabed deposition and burial rates to establish water-column and seabed preservation efficiencies for these materials. The project will substantially improve our understanding of the spring/summer production pulse on the WAP shelf and its impacts on seafloor communities and carbon cycling in Antarctic coastal systems.", "east": -60.499832, "geometry": "POINT(-65.703331 -59.672)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS", "is_usap_dc": false, "keywords": "R/V NBP; R/V LMG", "locations": null, "north": -52.35533, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Craig", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": "LTER", "south": -66.98867, "title": "Bentho-Pelagic Coupling on the West Antarctic Peninsula Shelf: The Impact and Fate of Bloom Material at the Seafloor", "uid": "p0000610", "west": -70.90683}, {"awards": "9419605 Dunbar, Robert; 9896356 Dunbar, Robert", "bounds_geometry": "POLYGON((-180 -43.56493,-144.00001 -43.56493,-108.00002 -43.56493,-72.00003 -43.56493,-36.00004 -43.56493,-0.000049999999987 -43.56493,35.99994 -43.56493,71.99993 -43.56493,107.99992 -43.56493,143.99991 -43.56493,179.9999 -43.56493,179.9999 -47.023783,179.9999 -50.482636,179.9999 -53.941489,179.9999 -57.400342,179.9999 -60.859195,179.9999 -64.318048,179.9999 -67.776901,179.9999 -71.235754,179.9999 -74.694607,179.9999 -78.15346,143.99991 -78.15346,107.99992 -78.15346,71.99993 -78.15346,35.99994 -78.15346,-0.000050000000016 -78.15346,-36.00004 -78.15346,-72.00003 -78.15346,-108.00002 -78.15346,-144.00001 -78.15346,-180 -78.15346,-180 -74.694607,-180 -71.235754,-180 -67.776901,-180 -64.318048,-180 -60.859195,-180 -57.400342,-180 -53.941489,-180 -50.482636,-180 -47.023783,-180 -43.56493))", "dataset_titles": "Expedition Data", "datasets": [{"dataset_uid": "002132", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9709"}, {"dataset_uid": "002094", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9807"}, {"dataset_uid": "002154", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9606"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "This project is an interdisciplinary study, titled Research on Ocean-Atmosphere Variability and Ecosystem Response in the Ross Sea (ROAVERRS), of atmospheric forcing, ocean hydrography, sea ice dynamics, primary productivity, and pelagic-benthic coupling in the southwestern Ross Sea, Antarctica. The primary goal is to examine how changes in aspects of the polar climate system, in this case wind and temperature, combine to influence marine productivity on a large antarctic continental shelf. In the Ross Sea, katabatic winds and mesocyclones influence the spatial and temporal distribution of sea ice as well as the upper ocean mixed layer depth, and thus control primary production within the sea ice as well as in the open water system. The structure, standing stock and productivity of bottom- dwelling biological communities are also linked to meteorological processes through interseasonal and interannual variations in horizontal and vertical fluxes of organic carbon produced in the upper ocean. Linkages among the atmospheric, oceanic, and biological systems will be investigated during a three-year field study of the southwestern Ross Sea ecosystem. Direct measurements will include regional wind and air temperatures derived from automatic weather stations; ice cover, ice movement, and sea surface temperatures derived from a variety of satellite-based sensors; hydrographic characteristics of the upper ocean and primary productivity in the ice and in the water derived from research cruises and satellite studies; vertical flux of organic material and water movement derived from oceanographic moorings containing sediment traps and current meters, and the abundance, distribution, and respiration rates of biological communities on the sea floor, derived from box cores, benthic photographs and shipboard incubations. Based on archived meteorological data, it is expected that the atmospheric variability during the study period will be such that changes in airflow pat terns and their influence on oceanographic and biological patterns can be monitored, and their direct and indirect linkages that are the focus of the research can be deduced. Results from this study will contribute to our knowledge of atmospheric and oceanic forcing of marine ecosystems, and lead to a better understanding of marine ecosystem response to climatic variations. ***", "east": 179.9999, "geometry": "POINT(0 -89.999)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS", "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": -43.56493, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences; Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Dunbar, Robert", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -78.15346, "title": "Research on Ocean-Atmosphere Variability and Ecosystem Response in the Ross Sea (ROAVERRS)", "uid": "p0000635", "west": -180.0}, {"awards": "9118439 Karl, David", "bounds_geometry": "POLYGON((-76.8432 -52.3533,-74.99221 -52.3533,-73.14122 -52.3533,-71.29023 -52.3533,-69.43924 -52.3533,-67.58825 -52.3533,-65.73726 -52.3533,-63.88627 -52.3533,-62.03528 -52.3533,-60.18429 -52.3533,-58.3333 -52.3533,-58.3333 -54.01689,-58.3333 -55.68048,-58.3333 -57.34407,-58.3333 -59.00766,-58.3333 -60.67125,-58.3333 -62.33484,-58.3333 -63.99843,-58.3333 -65.66202,-58.3333 -67.32561,-58.3333 -68.9892,-60.18429 -68.9892,-62.03528 -68.9892,-63.88627 -68.9892,-65.73726 -68.9892,-67.58825 -68.9892,-69.43924 -68.9892,-71.29023 -68.9892,-73.14122 -68.9892,-74.99221 -68.9892,-76.8432 -68.9892,-76.8432 -67.32561,-76.8432 -65.66202,-76.8432 -63.99843,-76.8432 -62.33484,-76.8432 -60.67125,-76.8432 -59.00766,-76.8432 -57.34407,-76.8432 -55.68048,-76.8432 -54.01689,-76.8432 -52.3533))", "dataset_titles": "Expedition Data", "datasets": [{"dataset_uid": "002292", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9302"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "The annual advance and retreat of pack ice may be the major physical determinant of spatial/temporal changes in the structure and function of antarctic marine communities. Interannual cycles and/or trends in the annual extent of pack ice may also have significant effects on all levels of the food web, from total annual primary production to breeding success in seabirds. Historical records indicate a 6 to 8 year cycle in the maximum extent of pack ice in the winter. During this decade winters were colder in 1980 and 1981, and again in 1986 and 1987. In order to understand the interactions between pack ice and ecosystem dynamics, especially the influences of the well- documented interannual variability in ice cover on representative populations, a long-term ecological research (LTER) site has been established in the Antarctic Peninsula region near Palmer Station. The LTER project, will conduct comprehensive measurements of ice-dominated ecosystems in this region with a focus on primary production, krill populations and swarms and seabirds. A primary emphasis will be placed on the development of ecosystem models that will provide a predictive capability for issues related to global environmental change. This proposal will add to the existing LTER project detailed studies of the biogeochemical cycling of carbon and associated bioelements. The microbiology and carbon flux component of LTER will provide measurements of a suite of core parameters relevant to the carbon cycle and will test several hypotheses pertaining to carbon flux, including bacterial productivity and nutrient regeneration.", "east": -58.3333, "geometry": "POINT(-67.58825 -60.67125)", "instruments": null, "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": -52.3533, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Karl, David; Ross, Robin Macurda", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": "LTER", "south": -68.9892, "title": "Long-term Ecological Research (LTER) on the Antarctic Marine Ecosystem: Microbiology and Carbon Flux", "uid": "p0000651", "west": -76.8432}, {"awards": "9011927 Ross, Robin; 9632763 Smith, Raymond", "bounds_geometry": "POLYGON((-79.68459 -52.36474,-77.851019 -52.36474,-76.017448 -52.36474,-74.183877 -52.36474,-72.350306 -52.36474,-70.516735 -52.36474,-68.683164 -52.36474,-66.849593 -52.36474,-65.016022 -52.36474,-63.182451 -52.36474,-61.34888 -52.36474,-61.34888 -54.071087,-61.34888 -55.777434,-61.34888 -57.483781,-61.34888 -59.190128,-61.34888 -60.896475,-61.34888 -62.602822,-61.34888 -64.309169,-61.34888 -66.015516,-61.34888 -67.721863,-61.34888 -69.42821,-63.182451 -69.42821,-65.016022 -69.42821,-66.849593 -69.42821,-68.683164 -69.42821,-70.516735 -69.42821,-72.350306 -69.42821,-74.183877 -69.42821,-76.017448 -69.42821,-77.851019 -69.42821,-79.68459 -69.42821,-79.68459 -67.721863,-79.68459 -66.015516,-79.68459 -64.309169,-79.68459 -62.602822,-79.68459 -60.896475,-79.68459 -59.190128,-79.68459 -57.483781,-79.68459 -55.777434,-79.68459 -54.071087,-79.68459 -52.36474))", "dataset_titles": "Expedition Data; Expedition data of NBP0105", "datasets": [{"dataset_uid": "002045", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9906"}, {"dataset_uid": "001578", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0601"}, {"dataset_uid": "002605", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0105", "url": "https://www.rvdata.us/search/cruise/NBP0105"}, {"dataset_uid": "002292", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9302"}, {"dataset_uid": "001817", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0201"}, {"dataset_uid": "001613", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0501"}, {"dataset_uid": "001665", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0401"}, {"dataset_uid": "001488", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0901"}, {"dataset_uid": "001998", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0001"}, {"dataset_uid": "001884", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0101"}, {"dataset_uid": "001649", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0301"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "The annual advance and retreat of pack ice may be the major physical determinant of spatial and temporal changes in the structure and function of antarctic marine communities. Interannual cycles and/or trends in the annual extent of pack ice may also have significant effects on all levels of the food web, from total annual primary production to breeding success in seabirds. Historical records indicate a six to eight year cycle in the maximum extent of pack ice in the winter. During this decade, winters were colder in 1980 and 1981, and again in 1986 and 1987. Winter-over survival in Adelie penguins varied on the same cycle, higher in winters with heavy pack ice. This Long Term Ecological Research (LTER) project will define ecological processes linking the extent of annual pack ice with the biological dynamics of different trophic levels within antarctic marine communities. The general focus is on interannual variability in representative populations from the antarctic marine food web and on mechanistic linkages that control the observed variability in order to develop broader generalizations applicable to other large marine environments. To achieve these objectives, data from several spatial and temporal scales, including remote sensing, a field approach that includes an annual monitoring program, a series of process-oriented research cruises, and a modeling effort to provide linkages on multiple spatial and temporal scales between biological and environmental components of the ecosystem will be employed.", "east": -61.34888, "geometry": "POINT(-70.516735 -60.896475)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; 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 PRESSURE/HEIGHT METERS \u003e PRESSURE SENSORS; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e TURBIDITY METERS; IN SITU/LABORATORY INSTRUMENTS \u003e MAGNETIC/MOTION SENSORS \u003e GRAVIMETERS \u003e GRAVIMETERS", "is_usap_dc": false, "keywords": "R/V LMG; R/V NBP", "locations": null, "north": -52.36474, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Smith, Raymond; Ross, Robin Macurda; Fraser, William; Martinson, Douglas; Ducklow, Hugh", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": "LTER", "south": -69.42821, "title": "Long-Term Ecological Research on the Antarctic Marine Ecosystem: An Ice-Dominated Environment", "uid": "p0000236", "west": -79.68459}, {"awards": "9615342 Neale, Patrick", "bounds_geometry": null, "dataset_titles": "Expedition data of LMG9809", "datasets": [{"dataset_uid": "002720", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG9809", "url": "https://www.rvdata.us/search/cruise/LMG9809"}, {"dataset_uid": "002719", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG9809", "url": "https://www.rvdata.us/search/cruise/LMG9809"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "Neale 9615342 Increases in ultraviolet-B radiation (UV-B, 280-320) associated with the Antarctic ozone hole have been shown to inhibit the photosynthesis of phytoplankton, but the overall effect on water column production is still a matter of debate and continued investigation. Investigations have also revealed that even at \"normal\" levels of Antarctic stratospheric ozone, UV-B and UV-A (320-400 nm) appear to have strong effects on water column production. The role of UV in the ecology of phytoplankton primary production has probably been underappreciated in the past and could be particularly important to the estimation of primary production in the presence of vertical mixing. This research focuses on quantifying UV effects on photosynthesis of Antarctic phytoplankton by defining biological weighting functions for UV-inhibition. In the past, techniques were developed to describe photosynthesis as a function of UV and visible irradiance using laboratory cultures. Further experimentation with natural assemblages from McMurdo Station in Antarctica showed that biological weighting functions are strongly related to light history. Most recently, measurements in the open waters of the Southern Ocean confirmed that there is substantial variability in the susceptibility of phytoplankton assemblages to UV. It was also discovered that inhibition of photosynthesis in Antarctic phytoplankton got progressively worse on the time scale of hours, with no evidence of recovery. Even under benign conditions, losses of photosynthetic capability persisted unchanged for several hours. This was in contrast with laboratory cultures and some natural assemblages which quickly attained a steady- state rate of photosynthesis during exposure to UV, reflecting a balance between damage and recovery processes. Slow reversal of UV-induced damage has profound consequences for water-column photosynthesis, especially during vertical mixing. Results to date have been used to model th e influence of UV, ozone depletion and vertical mixing on photosynthesis in Antarctic waters. Data indicate that normal levels of UV can have a significant impact on natural phytoplankton and that the effects can be exacerbated by ozone depletion as well as vertical mixing. Critical questions remain poorly resolved, however, and these are the focus of the present proposal. New theoretical and experimental approaches will be used to investigate UV responses in both the open waters of the Weddell-Scotia confluence and coastal waters near Palmer Station. In particular, measurements will be made of the kinetics of UV inhibition and recovery on time scales ranging from minutes to days. Variability in biological weighting functions between will be calculated for pelagic and coastal phytoplankton in the Southern Ocean. The results will provide absolute estimates of photosynthesis under in situ, as well as under altered, UV irradiance; broaden the range of assemblages for which biological weighting functions have been determined; and clarify how kinetics of inhibition and recovery should be represented in mixed layer models.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "R/V LMG", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Mopper, Kenneth; Neale, Patrick", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "New Approaches to Measuring and Understanding the Effects of Ultraviolet Radiation on Photosynthesis by Antarctic Phytoplankton", "uid": "p0000871", "west": null}, {"awards": "9220373 Neale, Patrick", "bounds_geometry": null, "dataset_titles": "Expedition Data; Expedition data of NBP9306", "datasets": [{"dataset_uid": "002282", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/NBP9306"}, {"dataset_uid": "002589", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP9306", "url": "https://www.rvdata.us/search/cruise/NBP9306"}], "date_created": "Fri, 19 Jun 2009 00:00:00 GMT", "description": "Increases in middle ultraviolet radiation associated with the Antarctic ozone hole have been shown to inhibit the photosynthesis of phytoplankton, and results have been extrapolated to estimate the effect of ozone depletion on primary productivity in the marginal ice zone. This research will refine the assessment by specifying detailed wavelength-dependent biological weighting functions for the inhibition of photosynthesis by ultraviolet radiation, and by considering the mitigating effects of vertical mixing. Biological weighting functions of phytoplankton in the marginal ice zone will be measured under controlled conditions and applied in a new model of photosynthesis to predict primary productivity in situ, as well as under altered ultraviolet irradiance. These predictions will be compared with observations on samples from the water column and with measurements during incubations of several hours under different irradiance regimes. Results of these comparisons will be used to test the model and to quantify the potential artifact of long incubations. Assumptions about the kinetics of photoinhibition and recovery, critical to modeling the effects of vertical mixing, will be examined with time-course experiments. Results will be incorporated into a model of photosynthesis and photoinhibition in the water column that will be used to predict the influence of ozone depletion on marine primary production, particularly in the marginal zone.", "east": null, "geometry": null, "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS", "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Neale, Patrick", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Effects of Ultraviolet Radiation on the Photosynthesis of Phytoplankton in the Antarctic Marginal Ice Zone", "uid": "p0000808", "west": null}, {"awards": "0742057 Gallager, Scott", "bounds_geometry": "POLYGON((-168.291 -64.846,-165.018 -64.846,-161.745 -64.846,-158.472 -64.846,-155.199 -64.846,-151.926 -64.846,-148.653 -64.846,-145.38 -64.846,-142.107 -64.846,-138.834 -64.846,-135.561 -64.846,-135.561 -66.0269,-135.561 -67.2078,-135.561 -68.3887,-135.561 -69.5696,-135.561 -70.7505,-135.561 -71.9314,-135.561 -73.1123,-135.561 -74.2932,-135.561 -75.4741,-135.561 -76.655,-138.834 -76.655,-142.107 -76.655,-145.38 -76.655,-148.653 -76.655,-151.926 -76.655,-155.199 -76.655,-158.472 -76.655,-161.745 -76.655,-165.018 -76.655,-168.291 -76.655,-168.291 -75.4741,-168.291 -74.2932,-168.291 -73.1123,-168.291 -71.9314,-168.291 -70.7505,-168.291 -69.5696,-168.291 -68.3887,-168.291 -67.2078,-168.291 -66.0269,-168.291 -64.846))", "dataset_titles": "SGER: Primary and Secondary Production and Carbon Flux Through the Microbial Community Along the Western Antarctic Marginal Ice Zone on the Oden Southern Ocean 2007 Expeditions", "datasets": [{"dataset_uid": "600086", "doi": "10.15784/600086", "keywords": "Amundsen Sea; Biota; Microbiology; Navigation; Oceans; Oden; OSO2007; Sample/collection Description; Sample/Collection Description; Southern Ocean", "people": "Gallager, Scott; Dennett, Mark", "repository": "USAP-DC", "science_program": null, "title": "SGER: Primary and Secondary Production and Carbon Flux Through the Microbial Community Along the Western Antarctic Marginal Ice Zone on the Oden Southern Ocean 2007 Expeditions", "url": "https://www.usap-dc.org/view/dataset/600086"}], "date_created": "Mon, 16 Mar 2009 00:00:00 GMT", "description": "Abstract\u003cbr/\u003e\u003cbr/\u003eThe research will continue and extend the study in the Southern Ocean that was initiated during the Oden Southern Ocean 2006 expedition in collaboration with Swedish scientist Mellissa Chierici. We will quantify carbon flux through the food web in the marginal ice zone (MIZ) by measuring size fractionated primary and secondary production, grazing and carbon flux through nanoplankton (2-20 um), microplankton (20-200um), and mesoplankton (200-2000 um). Community structure, species abundance and size specific grazing rates will be quantified using a variety of techniques both underway and at ice stations along the MIZ. The proposed cruise track extends across the Drake Passage to the Western Antarctic Peninsula (WAP) with three station transects along a gradient from the open ocean through the marginal ice zone (MIZ) in the Bellinghausen and Amundsen Seas and into the Ross Sea Polynya. Ice stations along each transect will provide material to characterize production associated with annual ice. Underway measurements of primary and secondary production (chlorophyll, CDOM, microplankton, and mesoplankton) and hydrography (temperature, salinity, pH, DO, turbidity) will establish a baseline for future cruises and as support for other projects such as biogeochemical studies on carbon dioxide drawdown and trace metal work on primary production. The outcome of these measurements will be a description of nano to mesoplankton standing stocks, community structure, and carbon flux along the MIZ in the Bellinghausen and Amundsen Seas and the Ross Sea Polynya.", "east": -135.561, "geometry": "POINT(-151.926 -70.7505)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -64.846, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Gallager, Scott; Dennett, Mark", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -76.655, "title": "SGER: Primary and Secondary Production and Carbon Flux Through the Microbial Community Along the Western Antarctic Marginal Ice Zone on the Oden Southern Ocean 2007 Expeditions", "uid": "p0000563", "west": -168.291}, {"awards": "0230276 Ward, Bess", "bounds_geometry": "POLYGON((162 -77.2,162.16 -77.2,162.32 -77.2,162.48 -77.2,162.64 -77.2,162.8 -77.2,162.96 -77.2,163.12 -77.2,163.28 -77.2,163.44 -77.2,163.6 -77.2,163.6 -77.26,163.6 -77.32,163.6 -77.38,163.6 -77.44,163.6 -77.5,163.6 -77.56,163.6 -77.62,163.6 -77.68,163.6 -77.74,163.6 -77.8,163.44 -77.8,163.28 -77.8,163.12 -77.8,162.96 -77.8,162.8 -77.8,162.64 -77.8,162.48 -77.8,162.32 -77.8,162.16 -77.8,162 -77.8,162 -77.74,162 -77.68,162 -77.62,162 -77.56,162 -77.5,162 -77.44,162 -77.38,162 -77.32,162 -77.26,162 -77.2))", "dataset_titles": "What Limits Denitrification and Bacterial Growth in Lake Bonney, Taylor Valley, Antarctica?", "datasets": [{"dataset_uid": "600033", "doi": "10.15784/600033", "keywords": "Antarctica; Biota; CTD Data; Dry Valleys; Lake Bonney; Lake Vanda; Microbiology; Taylor Valley", "people": "Ward, Bess", "repository": "USAP-DC", "science_program": null, "title": "What Limits Denitrification and Bacterial Growth in Lake Bonney, Taylor Valley, Antarctica?", "url": "https://www.usap-dc.org/view/dataset/600033"}], "date_created": "Sun, 18 Jan 2009 00:00:00 GMT", "description": "Denitrification is the main process by which fixed nitrogen is lost from ecosystems and the regulation of this process may directly affect primary production and carbon cycling over short and long time scales. Previous investigations of the role of bioactive metals in regulating denitrification in bacteria from permanently ice-covered Lake Bonney in the Taylor Valley of East Antarctica indicated that denitrifying bacteria can be negatively affected by metals such as copper, iron, cadmium, lead, chromium, nickel, silver and zinc; and that there is a distinct difference in denitrifying activity between the east and west lobes of the lake. Low iron concentrations were found to exacerbate the potential toxicity of the other metals, while silver has the potential to specifically inhibit denitrification because of its ability to interfere with copper binding in redox proteins, such as nitrite reductase and nitrous oxide reductase. High silver concentrations might prevent the functioning of nitrous oxide reductase in the same way that simple copper limitation does, thereby causing the buildup of nitrous oxide and resulting in a nonfunctional nitrogen cycle. Other factors, such as oxygen concentration, are likely also to affect bacterial activity in Lake Bonney. This project will investigate silver toxicity, general metal toxicity and oxygen concentration to determine their effect on denitrification in the lake by using a suite of \"sentinel\" strains of denitrifying bacteria (isolated from the lake) incubated in Lake Bonney water and subjected to various treatments. The physiological responses of these strains to changes in metal and oxygen concentration will be quantified by flow cytometric detection of single cell molecular probes whose sensitivity and interpretation have been optimized for the sentinel strains. Understanding the relationships between metals and denitrification is expected to enhance our understanding of not only Lake Bonney\u0027s unusual nitrogen cycle, but more generally, of the potential role of metals in the regulation of microbial nitrogen transformations.\u003cbr/\u003e\u003cbr/\u003eThe broader impacts of this work include not only a better understanding of regional biogeochemistry and global perspectives on these processes; but also the training of graduate students and a substantial outreach effort for school children.", "east": 163.6, "geometry": "POINT(162.8 -77.5)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD", "is_usap_dc": true, "keywords": "FIELD SURVEYS", "locations": null, "north": -77.2, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Ward, Bess", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.8, "title": "Collaborative Research: What Limits Denitrification and Bacterial Growth in Lake Bonney, Taylor Valley, Antarctica?", "uid": "p0000223", "west": 162.0}, {"awards": "0444040 Zhou, Meng; 0443403 Measures, Christopher; 0230445 Measures, Christopher", "bounds_geometry": "POLYGON((-63 -60.3,-62 -60.3,-61 -60.3,-60 -60.3,-59 -60.3,-58 -60.3,-57 -60.3,-56 -60.3,-55 -60.3,-54 -60.3,-53 -60.3,-53 -60.77,-53 -61.24,-53 -61.71,-53 -62.18,-53 -62.65,-53 -63.12,-53 -63.59,-53 -64.06,-53 -64.53,-53 -65,-54 -65,-55 -65,-56 -65,-57 -65,-58 -65,-59 -65,-60 -65,-61 -65,-62 -65,-63 -65,-63 -64.53,-63 -64.06,-63 -63.59,-63 -63.12,-63 -62.65,-63 -62.18,-63 -61.71,-63 -61.24,-63 -60.77,-63 -60.3))", "dataset_titles": "Expedition Data", "datasets": [{"dataset_uid": "001663", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG0402"}], "date_created": "Mon, 12 Jan 2009 00:00:00 GMT", "description": "The Shackleton Fracture Zone (SFZ) in the Drake Passage defines a boundary between low and high phytoplankton waters. West of Drake Passage, Southern Ocean waters south of the Polar Front and north of the Antarctic continent shelf have very low satellite-derived surface chlorophyll concentrations. Chlorophyll and mesoscale eddy kinetic energy are higher east of SFZ compared to values west of the ridge. In situ data from a 10-year survey of the region as part of the National Marine Fisheries Service\u0027s Antarctic Marine Living Resources program confirm the existence of a strong hydrographic and chlorophyll gradient in the region. An interdisciplinary team of scientists hypothesizes that bathymetry, including the 2000 m deep SFZ, influences mesoscale circulation and transport of iron leading to the observed phytoplankton patterns. To address this\u003cbr/\u003ehypothesis, the team proposes to examine phytoplankton and bacterial physiological states (including responses to iron enrichment) and structure of the plankton communities from virus to zooplankton, the concentration and distribution of Fe, Mn, and Al, and mesoscale flow patterns near the SFZ. Relationships between iron concentrations and phytoplankton characteristics will be examined in the context of the mesoscale transport of trace nutrients to determine how much of the observed variability in phytoplankton biomass can be attributed to iron supply, and to determine the most important sources of iron to pelagic waters east of the Drake Passage. The goal is to better understand how plankton productivity and community structure in the Southern Ocean are affected by the coupling between bathymetry, mesoscale circulation, and limiting nutrient distributions.\u003cbr/\u003e\u003cbr/\u003eThe research program includes rapid surface surveys of chemical, plankton, and hydrographic properties complemented by a mesoscale station grid for vertical profiles, water sampling, and bottle incubation enrichment experiments. Distributions of manganese and aluminum will be determined to help distinguish aeolian, continental shelf and upwelling sources of iron. The physiological state of the phytoplankton will be monitored by active fluorescence methods sensitive to the effects of iron limitation. Mass concentrations of pigment, carbon and nitrogen will be obtained by analysis of filtered samples, cell size distributions by flow cytometry, and species identification by microscopy. Primary production and photosynthesis parameters (absorption, quantum yields, variable fluorescence) will be measured on depth profiles, during surface surveys and on bulk samples from enrichment experiments. Viruses and bacteria will be examined for abundances, and bacterial production will be assessed in terms of whether it is limited by either iron or organic carbon sources. The proposed work will improve our understanding of processes controlling distributions of iron and the response of plankton communities in the Southern Ocean. This proposal also includes an outreach component comprised of Research Experiences for Undergraduates (REU), Teachers Experiencing the Antarctic and Arctic (TEA), and the creation of an educational website and K-12 curricular modules based on the project.", "east": -53.0, "geometry": "POINT(-58 -62.65)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e PRESSURE/HEIGHT METERS \u003e PRESSURE SENSORS; 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", "is_usap_dc": true, "keywords": "R/V LMG", "locations": null, "north": -60.3, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Measures, Christopher; Selph, Karen; Zhou, Meng", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": -65.0, "title": "Collaborative Research: Plankton Community Structure and Iron Distribution in the Southern Drake Passage", "uid": "p0000585", "west": -63.0}]
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Phytoplankton, or microscopic marine algae, are an important part of the carbon cycle and can lower the rates of atmospheric carbon dioxide by transferring the atmospheric carbon into the oceans. The concentration of phytoplankton in the Southern Ocean is regularly limited by the availability of marine iron. This in turn influences the rate of carbon transfer from the atmosphere to the ocean. The primary source of iron in the Southern Ocean is eroded continental rock. Understanding the current and future sources of iron to the Southern Ocean as a result of increased melting of terrestrial glaciers is necessary for predicting future concentrations of Southern Ocean phytoplankton and the subsequent influence on the carbon cycle. A poorly understood source of iron to the Southern Ocean is stream input from ice-free regions such as the McMurdo Dry Valleys in Antarctica. This source of iron is likely to become larger if glaciers retreat. This study investigates the sources and amount of iron transported by McMurdo Dry Valley streams directly into the Southern Ocean. Because not all forms of iron can be used by phytoplankton, experiments will be performed to determine how available iron is to phytoplankton and how iron mixes with seawater. Immersive 360-degree video, infographics, and educational videos of findings from this project will be shared on social media, at schools and science events, and in an urban science center. In the Southern Ocean (SO) there is an excess of macronutrients but regional primary production is limited or co-limited due to iron. An addition of iron to the ocean will affect biochemical cycles, increase primary production, and affect the structure and composition of phytoplankton communities in the SO. Iron flux to the SO is globally significant, as increased Fe fertilization leads to increased carbon sequestration which acts as a negative feedback to increased atmospheric pCO2. One source of potentially bioavailable iron to the coastal regions of the SO is from direct sub-aerial stream discharge in ice-free areas of Antarctica, a source that may become more important if terrestrial glaciers retreat. It is imperative to understand the source, nature, potential fate, and flux of iron to the SO if better predictive models for the carbon cycle and atmospheric chemistry are to be developed. This project will investigate in-stream processes and characteristics controlling dissolved iron draining into the Ross Sea including photoreduction, temperature, and complexation with organic matter. The novel study will quantify bioavailability of particulate iron and bioavailability of dissolved iron in Antarctic in streams draining into the SO. On-site speciation measurements will be performed on dissolved iron species, particulate iron speciation will be determined using high-resolution spectroscopy, mixing experiments will be performed with coastal marine water, and the bioavailability of Fe will be determined through marine bioassays. This project will provide two students with valuable Antarctic field experience and reach thousands of individuals through existing partnerships with K-12 schools, public STEM events, an urban science center, and a strong social media presence. 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.
Sea ice in Antarctic coastal waters shape ecosystems, both in the surface waters and at the bottom of the ocean, environments that depend on algae living in sea ice for their productivity. With high variability in sea ice formation and melt between years and as a response to climate change, it is of importance to obtain better understanding of the interaction of sea ice with algae, as well as provide better data for global climate models. This project will accomplish those goals by measuring phytoplankton growth and cellular properties in sea ice with experiments performed using an ice tank. Laboratory experiments will be based on previous observations in the Antarctic Peninsula coastal waters, providing realistic conditions to emulate. The scientific importance of the proposed work aligns with the National Science Foundation goals to understand the biological and chemical properties of sea ice bio-geo-chemistry and its feedbacks with seasonal sea ice dynamics and climate. The finding from this project will be of interest to a broad scientific community, including oceanographers, biologists, chemists, and ecosystem and ocean modelers. To address the scarcity of data on sea ice microbes that limits our ability to predict future Antarctic climate with accuracy, the principal investigator will develop an Antarctic Science Minor in order to train future scientists with an environmental perspective and prepare the future US workforce with a strong scientific background on Earth and Biological Sciences. There is a paucity of data to understand the processes underlying observed patters in sea ice quality and their interaction with the sea-ice microbial community. This project will provide a mechanistic understanding of primary production and physiology of sympagic algae over the seasonal cycle of formation and melt of Antarctic sea ice. Although sea ice is central to the Antarctic coastal ecosystems, little is known of how they affect, and are in turn affected, by sea-ice algae. This project concentrates on first-year sea ice, forming and melting each year, creating unique and very dynamic habitats. The study will be structured by 4 main objectives: 1) how different algal species adapt to the seasonal changes in sea ice conditions, 2) how different methods to measure primary production (carbon dioxide drawdown, oxygen production and variable fluorescence) relate in sea ice and differ from sea water measurements, 3) how sympagic algae influence the physical structure of sea ice, 4) how sympagic algae contribute to organic matter cycling during ice melt. Due to expected changes in sea ice due to climate change, this study is uniquely positioned to provide needed data on short-term and seasonal processes. Results from this study will be useful to refine models of algal production in Antarctic and Arctic ecosystems, data not available to date as sea ice and its biogeochemistry are often poorly represented in earth system models. This project will also provide education for graduate and undergraduate students as well as material to develop class curriculum for middle-school students. 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.
Arrigo, Kevin; Thomas, Leif N; Baumberger, Tamara; Resing, Joseph
No dataset link provided
Phytoplankton blooms throughout the world’s oceans support critical marine ecosystems and help remove carbon dioxide (CO2) from the atmosphere. Traditionally, it has been assumed that phytoplankton blooms in the Southern Ocean are stimulated by iron from either nearby land or sea-ice. However, recent work demonstrates that hydrothermal vents may be an additional iron source for phytoplankton blooms. This enhancement of phytoplankton productivity by different iron sources supports rich marine ecosystems and leads to the sequestration of carbon in the deep ocean. Our proposed work will uncover the importance of hydrothermal activity in stimulating a large phytoplankton bloom along the southern boundary of the Antarctic Circumpolar Current just north of the Ross Sea. It will also lead towards a better understanding of the overall impact of hydrothermal activity on the carbon cycle in the Southern Ocean, which appears to trigger local hotspots of biological activity which are a potential sink for atmospheric CO2. This project will encourage the participation of underrepresented groups in ocean sciences, as well as providing educational opportunities for high school and undergraduate students, through three different programs. Stanford University’s Summer Undergraduate Research in Geoscience and Engineering (SURGE) program provides undergraduates from different US universities and diverse cultural backgrounds the opportunity to spend a summer doing a research project at Stanford. The Stanford Earth Summer Undergraduate Research Program (SESUR) is for Stanford undergraduates who want to learn more about environmental science by performing original research. Finally, Stanford’s School of Earth, Energy, and Environmental Sciences High School Internship Program enables young scientists to serve as mentors, prepares high school students for college, and serves to strengthen the partnership between Stanford and local schools. Students present their results at the Fall AGU meeting as part of the AGU Bright STaRS program. This project will form the basis of at least two PhD dissertations. The Stanford student will participate in Stanford’s Woods Institute Rising Environmental Leaders Program (RELP), a year-round program that helps graduate students hone their leadership and communication skills to maximize the impact of their research. The graduate student will also participate in Stanford’s Grant Writing Academy where they will receive training in developing and articulating research strategies to tackle important scientific questions. This interdisciplinary program combines satellite and ship-based measurements of a large poorly understood phytoplankton bloom (the AAR bloom) in the northwestern Ross Sea sector of the Southern Ocean with a detailed modeling study of the physical processes linking deep dissolved iron (DFe) reservoirs to the surface phytoplankton bloom. Prior to the cruise, we will implement a numerical model (CROCO) for our study region so that we can better understand the circulation, plumes, turbulence, fronts, and eddy field around the AAR bloom and how they transport and mix hydrothermally produced DFe vertically. Post cruise, observations of the vertical distribution of 3He (combined with DMn and DFe), will be used as initial conditions for a passive tracer in the model, and tracer dispersal will be assessed to better quantify the role of the various turbulent processes in upwelling DFe-rich waters to the upper ocean. The satellite-based component of the program will characterize the broader sampling region before, during, and after our cruise. During the cruise, our automated software system at Stanford University will download and process images of sea ice concentration, Chl-a concentration, sea surface temperature (SST), and sea surface height (SSH) and send them electronically to the ship. Operationally, our goal is to use all available satellite data and preliminary model results to target shipboard sampling both geographically and temporally to optimize sampling of the AAR bloom. We will use available BGC-Argo float data to help characterize the AAR bloom. In collaboration with SOCCOM, we will deploy additional BGC-Argo floats (if available) during our transit through the study area to allow us to better characterize the bloom. The centerpiece of our program will be a 40-day process study cruise in austral summer. The cruise will consist of an initial “radiator” pattern of hydrographic surveys/sections along the AAR followed by CTDs to selected submarine volcanoes. When/if eddies are identified, they will be sampled either during or after the initial surveys. The radiator pattern, or parts thereof, will be repeated 2-3 times. Hydrographic survey stations will include vertical profiles of temperature, salinity, oxygen, oxidation-reduction potential, light scatter, and PAR (400-700 nm). Samples will be collected for trace metals, ligands, 3He, and total suspended matter. Where intense hydrothermal activity is identified, samples for pH and total CO2 will also be collected to characterize the hydrothermal system. Water samples will be collected for characterization of macronutrients, and phytoplankton physiology, abundance, species composition, and size. During transits, we will continuously measure atmospheric conditions, current speed and direction, and surface SST, salinity, pCO2, and fluorescence from the ship’s systems to provide detailed maps of these parameters. The ship will be used as a platform for conducting phytoplankton DFe bioassay experiments at key stations throughout the study region both inside and outside the bloom. We will also perform detailed comparisons of algal taxonomic composition, physiology, and size structure inside and outside the bloom to determine the potential importance of each community on local biogeochemistry. 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.
Traditional models of oceanic food chains have consisted of photosynthetic algae (phytoplankton) being ingested by small animals (zooplankton), which were ingested by larger animals (fish). These traditional models changed as new methods allowed recognition of the importance of bacteria and other non-photosynthetic protozoa in more complex food webs. More recently, the wide-spread existence of mixotrophs (organisms that can both photosynthesize and ingest food particles) and their importance as microbial predators has been recognized in many oceanographic areas. In the Southern Ocean, the only two surveys of mixotrophs have suggested that there may be seasonal differences in their importance as predators. During the long polar night (winter), the ability of mixotrophs to ingest particulate food may aid in their survival thus ensuring a sufficient population in spring to support a phytoplankton bloom once photosynthesis rates can increase. Thus mixotrophs may provide a critical early food source upon which zooplankton and larger animals depend on for growth and reproduction. This project will advance understanding of mixotroph diversity and their ecological impact within the Southern Ocean microbial food web. Specifically, efforts will be focused on mixotrophy in the western Antarctica peninsula region during the austral spring and autumn when there are likely to be changes in the relative importance of photosynthesis and ingestion to mixotrophs. The project will provide research opportunities for undergraduate and graduate students and a post-doctoral researcher. There will be real-time outreach from the Southern Ocean to the public via blogs and interviews, and to high school art students through an established program that blends science and art education. Despite traditional views of protists as either "phototrophic" or "heterotrophic," there are many photosynthetic protists that consume prey (mixotrophy). Mixotrophy is a widespread phenomenon in aquatic systems and phytoplankton groups with known mixotrophic species, notably chrysophytes, cryptophytes, prymnesiophytes, prasinophytes and dinoflagellates, are present and often abundant in Antarctic waters. However, in the Southern Ocean, the presence of mixotrophic phytoflagellates has been surveyed only twice: in the Ross Sea during Austral spring 2008 and summer 2011. The primary goals of the project are to gain better understanding of mixotroph diversity and their ecological impact with respect to the Southern Ocean microbial food web. The contribution of mixotrophs to primary production and bacterial consumption is likely linked to the taxonomic composition of the community and the abundance of particular species. Abundances of novel mixotrophic species will be evaluated via qPCR, which will be coupled with assessments of rates of feeding and photosynthesis with the goal of describing how active mixotrophs direct the movement of carbon through food webs. These experiments will help the determination of how viable and widespread mixotrophy is as a nutritional strategy in polar waters and give direct information on the currently unknown diversity of mixotrophic taxa under different environmental conditions occurring in austral spring and autumn. Furthermore, the methods will simultaneously yield information on the whole communities of protists - mixotrophic, phototrophic and heterotrophic. In addition, a method to examine aspects of the taxonomic and functional diversities of the bacterivorous/mixotrophic community will be employed. A thymidine analog (BrdU) will be used to label DNA of eukaryotes feeding on bacteria. The BrdU-labeled eukaryotic DNA will be isolated using immunoprecipitation. High-throughput sequencing of the labeled DNA (bacterivores) versus unlabeled community DNA will determine the diversity of bacterivorous mixotrophs relative to other microeukaryotes. Flow cytometric sorting based on chlorophyll to focus on mixotrophic species. These approaches will elucidate a gap in current knowledge of the influence of microbial interactions in the Southern Ocean under different conditions. 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 collaborative study between the University of California, Santa Cruz, Duke University, the University of South Florida, the University of Alaska-Anchorage, and the University of California, San Diego will examine the identification of biological and physical features associated with the abundance and distribution of individual Antarctic predators; the identification and characterization of biological 'hot spots' within the Western Antarctic Peninsula; and the development of temporally and spatially explicit models of krill consumption within the WAP by vertebrate predators. It is one of several data synthesis and modeling components that use the data obtained in the course of the field work of the Southern Ocean Global Ocean Ecosystems Dynamics (SO GLOBEC) experiment.<br/>SO-Globec is a multidisciplinary effort focused on understanding the physical and biological factors that influence growth, reproduction, recruitment and survival of Antarctic krill (Euphausia superba). The program uses a multi-trophic level approach that includes the predators and competitors of Antarctic krill, represented by other zooplankton, fish, penguins, seals, and cetaceans. It is currently in a synthesis and modeling phase. This collaborative project is concerned with understanding how predators utilize 'hot spots', i.e. locally intense areas of biological productivity, and how 'hot spots' might temporally and spatially structure krill predation rates, and will be integrated with other synthesis and modeling studies that deal with the hydrography primary production, and krill dynamics.
Coastal waters surrounding Antarctica represent some of the most biologically rich and most untouched ecosystems on Earth. In large part, this biological richness is concentrated within the numerous openings that riddle the expansive sea ice (these openings are known as polynyas) near the Antarctic continent. These polynyas represent regions of enhanced production known as hot-spots and support the highest animal densities in the Southern Ocean. Many of them are also located adjacent to floating extensions of the vast Antarctic Ice Sheet and receive a substantial amount of meltwater runoff each year during the summer. However, little is known about the specific processes that make these ecosystems so biologically productive. Of the 46 Antarctic coastal polynyas that are presently known, only a handful have been investigated in detail. This project will develop ecosystem models for the Ross Sea polynya, Amundsen polynya, and Pine Island polynya; three of the most productive Antarctic coastal polynyas. The primary goal is to use these models to better understand the fundamental physical, chemical, and biological interacting processes and differences in these processes that make these systems so biologically productive yet different in some respects (e.g. size and productivity) during the present day settings. Modeling efforts will also be extended to potentially assess how these ecosystems may have functioned in the past and how they might change in the future under different physical and chemical and climatic settings. The project will advance the education of underrepresented minorities through Stanford?s Summer Undergraduate Research in Geoscience and Engineering (SURGE) Program. SURGE will provide undergraduates the opportunity to gain mentored research experiences at Stanford University in engineering and the geosciences. Old Dominion University also will utilize an outreach programs for local public and private schools as well as an ongoing program supporting the Boy Scout Oceanography merit badge program to create outreach and education impacts. Polynyas (areas of open water surrounded by sea ice) are disproportionately productive regions of polar ecosystems, yet controls on their high rates of production are not well understood. This project will provide quantitative assessments of the physical and chemical processes that control phytoplankton abundance and productivity within polynyas, how these differ for different polynyas, and how polynyas may change in the future. Of particular interest are the interactions among processes within the polynyas and the summertime melting of nearby ice sheets, including the Thwaites and Pine Island glaciers. In this proposed study, we will develop a set of comprehensive, high resolution coupled physical-biological models and implement these for three major, but diverse, Antarctic polynyas. These polynyas, the Ross Sea polynya, the Amundsen polynya, and Pine Island polynya, account for >50% of the total Antarctic polynya production. The research questions to be addressed are: 1) What environmental factors exert the greatest control of primary production in polynyas around Antarctica? 2) What are the controlling physics that leads to the heterogeneity of dissolved iron (dFe) supply to the euphotic zone in polynyas around the Antarctic continental shelf? What effect does this have on local rates of primary production? 3) What are the likely changes in the supply of dFe to the euphotic zone in the next several decades due to climate-induced changes in the physics (winds, sea-ice, ice shelf basal melt, cross-shelf exchange, stratification and vertical mixing) and how will this affect primary productivity around the continent? The Ross Sea, Amundsen, and Pine Island polynyas are some of the best-sampled polynyas in Antarctica, facilitating model parameterization and validation. Furthermore, these polynyas differ widely in their size, location, sea ice dynamics, relationship to melting ice shelves, and distance from the continental shelf break, making them ideal case studies. For comparison, the western Antarctic Peninsula (wAP), a productive continental shelf where polynyas are a relatively minor contributor to biological production, will also be modeled. Investigating specific processes within different types Antarctic coastal waters will provide a better understand of how these important biological oases function and how they might change under different environmental conditions.
Part 1: Nitrification is the conversion of ammonium to nitrate by a two-step process involving two different guilds of microorganisms: ammonia- and nitrite-oxidizers. The process is central to the global nitrogen cycle, affecting everything from retention of fertilizer on croplands to removal of excess nitrogen from coastal waters before it can cause blooms of harmful algae. It also produces nitrous oxide, an ozone-destroying, greenhouse gas. The energy derived from both steps of nitrification is used to convert inorganic carbon into microbial biomass. The biomass produced contributes to the overall food web production of the Southern Ocean and may be a particularly important subsidy during winter when low light levels restrict the other major source of biomass, primary production by single-celled plants. This project addresses three fundamental questions about the biology and geochemistry of polar oceans, with a focus on the process of nitrification. The first question the project will address concerns the contribution of chemoautotrophy (based on nitrification) to the overall supply of organic carbon to the food web of the Southern Ocean. Previous measurements indicate that it contributes about 9% to the Antarctic food web on an annual basis, but those measurements did not include the additional production associated with nitrite oxidation. The second question to be addressed is related to the first and concerns the coupling between the steps of the process. The third seeks to determine the significance of the contribution of other sources of nitrogen, (specifically organic nitrogen and urea released by other organisms) to nitrification because these contributions may not be assessed by standard protocols. Measurements made by others suggest that urea in particular might be as important as ammonium to nitrification in polar regions. This project will result in training a postdoctoral researcher and provide undergraduate students opportunities to gain hand-on experience with research on microbial geochemistry. The Palmer LTER (PAL) activities have focused largely on the interaction between ocean climate and the marine food web affecting top predators. Relatively little effort has been devoted to studying processes related to the microbial geochemistry of nitrogen cycling as part of the Palmer Long Term Ecological Research (LTER) program, yet these are a major themes at other sites. This work will contribute substantially to understanding an important aspect of nitrogen cycling and bacterioplankton production in the PAL-LTER study area. The team will be working synergistically and be participating fully in the education and outreach efforts of the Palmer LTER, including making highlights of the findings available for posting to their project web site and participating in any special efforts they have in the area of outreach. Part 2: The proposed work will quantify oxidation rates of 15N supplied as ammonium, urea and nitrite, allowing us to estimate the contribution of urea-derived N and complete nitrification (ammonia to nitrate) to chemoautotrophy and bacterioplankton production in Antarctic coastal waters. The project will compare these estimates to direct measurements of the incorporation of 14C into organic matter the dark for an independent estimate of chemoautotrophy. The team aims to collect samples spanning the water column: from surface water (~10 m), winter water (50-100 m) and circumpolar deep water (>150 m); on a cruise surveying the continental shelf and slope west of the Antarctic Peninsula in the austral summer of 2018. Other samples will be taken to measure the concentrations of nitrate, nitrite, ammonia and urea, for qPCR analysis of the abundance of relevant microorganisms, and for studies of related processes. The project will rely on collaboration with the existing Palmer LTER to ensure that ancillary data (bacterioplankton abundance and production, chlorophyll, physical and chemical variables) will be available. The synergistic activities of this project along with the LTER activities will provide a unique opportunity to assess chemoautotrophy in context of the overall ecosystem?s dynamics- including both primary and secondary production processes.
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.
The depletion of stratospheric ozone over Antarctica leads to abnormally high levels of ultraviolet radiation (UVR) from the sun reaching the surface of the ocean. This phenomenon is predicted to continue for the next half century, despite bans on ozone-destroying pollutants. Phytoplankton in the near surface ocean are subjected to variable amounts of UVR and contain a lot of lipids (fats). Because phytoplankton are at the base of the food chain their lipids makes their way into the Antarctic marine ecosystem's food web. The molecular structures of phytoplankton lipids are easily altered by UVR. When this happens, their lipids can be transformed from healthy molecules into potentially harmful molecules(oxylipins) known to be disruptive to reproductive and developmental processes. This project will use state-of-the-art molecular methods to answer questions about extent to which UVR damages lipid molecules in phytoplankton, and how these resultant molecules might effect the food chain in the ocean near Antarctica. Lipid peroxidation is often invoked as consequence of increased exposure of phytoplankton to UVR-produced reactive oxygen species (ROS), but the literature is practically silent on peroxidized lipids and their byproducts (i.e. oxylipins) in the ocean. In waters of the West Antarctic Peninsula (WAP), spring-time blooms of diatoms contribute significantly to overall marine primary production. Oxylipins from diatoms can be highly bioactive; their impact on zooplankton grazers, bacteria, and other phytoplankton has been the subject of intense study. However, almost all of this work has focused on the production of oxylipins via enzymatic pathways, not by pathways involving UVR and/or ROS. Furthermore, rigorous experimental work on the effects of oxylipins has been confined almost exclusively to pure cultures and artificial communities. Thus, the true potential of these molecules to disrupt carbon cycling is very poorly-constrained, and is entirely unknown in the waters of the WAP. Armed with new highly-sensitive, state-of-the-art analytical techniques based on high-mass-resolution mass spectrometry, the principal investigator and his research group have begun to uncover an exquisite diversity of oxylipins in natural WAP planktonic communities. These techniques will be applied to understand the connections between UVR, ROS, oxylipins, and carbon cycling. The project will answer the question of how UVR, via ROS, affects oxylipin production by diatoms in WAP surface waters in controlled experiments conducted at a field station. With the answer to this question in hand, the project will also seek to answer how this phenomenon impacts the flow of carbon, particularly the export of organic carbon from the system, during a research cruise. The level of UVR-induced stresses experienced by oxylipin-rich planktonic communities in the WAP is unique, making Antarctica the only location for answering these fundamental questions. Major activities will include laboratory experiments with artificial membranes and diatom cultures, as well field experiments with phytoplankton, zooplankton, and bacteria in WAP waters.
Rapid changes in the extent and thickness of sea ice during the austral spring subject microorganisms within or attached to the ice to large fluctuations in temperature, salinity, light and nutrients. This project aims to identify cellular responses in sea-ice algae to increasing temperature and decreasing salinity during the spring melt along the western Antarctic Peninsula and to determine how associated changes at the cellular level can potentially affect dynamic, biologically driven processes. Understanding how sea-ice algae cope with, and are adapted to, their environment will not only help predict how polar ecosystems may change as the extent and thickness of sea ice change, but will also provide a better understanding of the widespread success of photosynthetic life on Earth. The scientific context and resulting advances from the research will be communicated to the general public through outreach activities that includes work with Science Communication Fellows and the popular Polar Science Weekend at the Pacific Science Center in Seattle, Washington. The project will provide student training to college students as well as provide for educational experiences for K-12 school children. There is currently a poor understanding of feedback relationships that exist between the rapidly changing environment in the western Antarctic Peninsula region and sea-ice algal production. The large shifts in temperature and salinity that algae experience during the spring melt affect critical cellular processes, including rates of enzyme-catalyzed reactions involved in photosynthesis and respiration, and the production of stress-protective compounds. These changes in cellular processes are poorly constrained but can be large and may have impacts on local ecosystem productivity and biogeochemical cycles. In particular, this study will focus on the thermal sensitivity of enzymes and the cycling of compatible solutes and exopolymers used for halo- and cryo-protection, and how they influence primary production and the biogeochemical cycling of carbon and nitrogen. Approaches will include field sampling during spring melt, incubation experiments of natural sea-ice communities under variable temperature and salinity conditions, and controlled manipulation of sea-ice algal species in laboratory culture. Employment of a range of techniques, from fast repetition rate fluorometry and gross and net photosynthetic measurements to metabolomics and enzyme kinetics, will tease apart the mechanistic effects of temperature and salinity on cell metabolism and primary production with the goal of quantifying how these changes will impact biogeochemical processes along the western Antarctic Peninsula. 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 Southern Ocean surrounding Antarctica is changing rapidly in response to Earth's warming climate. These changes will undoubtedly influence communities of primary producers (the organisms at the base of the food chain, particularly plant-like organisms using sunlight for energy) by altering conditions that influence their growth and composition. Because primary producers such as phytoplankton play an important role in global biogeochemical cycling, it is essential to understand how they will respond to changes in their environment. The growth of phytoplankton in certain regions of the Southern Ocean is constrained by steep gradients in chemical and physical properties that vary in both space and time. Light and iron have been identified as key variables influencing phytoplankton abundance and distribution within Antarctic waters. Microscopic algae known as diatoms are dominant members of the phytoplankton and sea ice communities, accounting for significant proportions of primary production. The overall objective of this project is to identify the molecular bases for the physiological responses of polar diatoms to varying light and iron conditions. The project should provide a means of evaluating the extent these factors regulate diatom growth and influence net community productivity in Antarctic waters. The project will also further the NSF goals of making scientific discoveries available to the general public and of training new generations of scientists. It will facilitate the teaching and learning of polar-related topics by translating the research objectives into readily accessible educational materials for middle-school students. This project will also provide funding to enable a graduate student and several undergraduate students to be trained in the techniques and perspectives of modern biology. Although numerous studies have investigated how polar diatoms are affected by varying light and iron, the cellular mechanisms leading to their distinct physiological responses remain unknown. Using comparative transcriptomics, the expression patterns of key genes and metabolic pathways in several ecologically important polar diatoms recently isolated from Antarctic waters and grown under varying iron and irradiance conditions will be examined. In addition, molecular indicators for iron and light limitation will be developed within these polar diatoms through the identification of iron- and light-responsive genes -- the expression patterns of which can be used to determine their physiological status. Upon verification in laboratory cultures, these indicators will be utilized by way of metatranscriptomic sequencing to examine iron and light limitation in natural diatom assemblages collected along environmental gradients in Western Antarctic Peninsula waters. In order to fully understand the role phytoplankton play in Southern Ocean biogeochemical cycles, dependable methods that provide a means of elucidating the physiological status of phytoplankton at any given time and location are essential.
This EAGER project will compare gene expression patterns in the planktonic communities under ice covers that form in coastal embayment's in the Antarctic Peninsula. Previous efforts taking advantage of unique ice conditions in November and December of 2015 allowed researchers to conduct an experiment to examine the role of sea ice cover on microbial carbon and energy transfer during the winter-spring transition. The EAGER effort will enable the researchers to conduct the "omics" analyses of the phytoplankton to determine predominant means by which energy is acquired and used in these settings. This EAGER effort will apply new expertise to fill an existing gap in ecological observations along the West Antarctic Peninsula. The principle product of the proposed work will be a novel dataset to be analyzed and by an early career researcher from an underserved community (veteran). The critical baseline data contained in this dataset enable a comparison of eukaryotic and prokaryotic gene expression patterns to establish the relative importance of chemoautotrophy, heterotrophy, mixotrophy, and phototrophy during the experiments. this information and data will be made immediately available to the broader scientific community, and will enable the development of further hypotheses on ecosystem change as sea ice cover changes in the region. Very little gene expression data is currently available for the Antarctic marine environment, and no gene expression data is available during the ecologically critical winter to spring transition. Moreover, ice cover in bays is common along the West Antarctic Peninsula yet the opportunity to study cryptophyte phytoplankton physiology beneath such ice conditions in coastal embayments is rare.
The aim of study is to understand how climate-related changes in snow and ice affect predator populations in the Antarctic, using the Adélie penguin as a focal species due to its long history as a Southern Ocean 'sentinel' species and the number of long-term research programs monitoring its abundance, distribution, and breeding biology. Understanding the environmental factors that control predator population dynamics is critically important for projecting the state of populations under future climate change scenarios, and for designing better conservation strategies for the Antarctic ecosystem. For the first time, datasets from a network of observational sites for the Adélie penguin across the entire Antarctic will be combined and analyzed, with a focus on linkages among the ice environment, primary production, and the population responses of Adélie penguins. The project will also further the NSF goals of making scientific discoveries available to the general public and of training new generations of scientists. The results of this project can be used to illustrate intuitively to the general public the complex interactions between ice, ocean, pelagic food web and top predators. This project also offers an excellent platform to demonstrate the process of climate-change science - how scientists simulate climate change scenarios and interpret model results. This project supports the training of undergraduate and graduate students in the fields of polar oceanography, plankton and seabird ecology, coupled physical-biological modeling and mathematical ecology. The results will be broadly disseminated to the general oceanographic research community through scientific workshops, conferences and peer-reviewed journal articles, and to undergraduate and graduate education communities, K-12 schools and organizations, and the interested public through web-based servers using existing infrastructure at the investigators' institutions. The key question to be addressed in this project is how climate impacts the timing of periodic biological events (phenology) and how interannual variation in this periodic forcing influences the abundance of penguins in the Antarctic. The focus will be on the timing of ice algae and phytoplankton blooms because the high seasonality of sea ice and associated pulsed primary productivity are major drivers of the Antarctic food web. This study will also examine the responses of Adélie penguins to changes in sea ice dynamics and ice algae-phytoplankton phenology. Adélie penguins, like many other Antarctic seabirds, are long-lived, upper trophic-level predators that integrate the effects of sea ice on the food web at regional scales, and thus serve as a reliable biological indicator of environmental changes. The proposed approach is designed to accommodate the limits of measuring and modeling the intermediate trophic levels between phytoplankton and penguins (e.g., zooplankton and fish) at the pan-Antarctic scale, which are important but latent variables in the Southern Ocean food web. Through the use of remotely sensed and in situ data, along with state of the art statistical approaches (e.g. wavelet analysis) and numerical modeling, this highly interdisciplinary study will advance our understanding of polar ecosystems and improve the projection of future climate change scenarios.
The biota of the world's seafloor is fueled by bursts of seasonal primary production. For food-limited sediment communities to persist, a balance must exist between metazoan consumption of and competition with bacteria, a balance which likely changes through the seasons. Polar marine ecosystems are ideal places to study such complex interactions due to stark seasonal shifts between heterotrophic and autotrophic communities, and temperatures that may limit microbial processing of organic matter. The research will test the following hypotheses: 1) heterotrophic bacteria compete with macrofauna for food; 2) as phytoplankton populations decline macrofauna increasingly consume microbial biomass to sustain their populations; and 3) in the absence of seasonal photosynthetic inputs, macrofaunal biodiversity will decrease unless supplied with microbially derived nutrition. Observational and empirical studies will test these hypotheses at McMurdo Station, Antarctica, where a high-abundance macro-infaunal community is adapted to this boom-and-bust cycle of productivity. The investigator will mentor undergraduates from a predominantly minority-serving institution, in the fields of invertebrate taxonomy and biogeochemistry. The general public and young scientists will be engaged through lectures at local K-12 venues and launch of an interactive website. The results will better inform scientists and managers about the effects of climate change on polar ecosystems and the mechanisms of changing productivity patterns on global biodiversity.
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.
The Ross Sea continental shelf is one of the most productive areas in the Southern Ocean, and may comprise a significant, but unaccounted for, oceanic CO2 sink, largely driven by phytoplankton production. The processes that control the magnitude of primary production in this region are not well understood, but data suggest that iron limitation is a factor. Field observations and model simulations indicate four potential sources of dissolved iron to surface waters of the Ross Sea: (1) circumpolar deep water intruding from the shelf edge; (2) sediments on shallow banks and nearshore areas; (3) melting sea ice around the perimeter of the polynya; and (4) glacial meltwater from the Ross Ice Shelf. The principal investigators hypothesize that hydrodynamic transport via mesoscale currents, fronts, and eddies facilitate the supply of dissolved iron from these four sources to the surface waters of the Ross Sea polynya. These hypotheses will be tested through a combination of in situ observations and numerical modeling, complemented by satellite remote sensing. In situ observations will be obtained during a month-long cruise in the austral summer. The field data will be incorporated into model simulations, which allow quantification of the relative contributions of the various hypothesized iron supply mechanisms, and assessment of their impact on primary production. The research will provide new insights and a mechanistic understanding of the complex oceanographic phenomena that regulate iron supply, primary production, and biogeochemical cycling. The research will thus form the basis for predictions about how this system may change in a warming climate. The broader impacts include training of graduate and undergraduate students, international collaboration, and partnership with several ongoing outreach programs that address scientific research in the Southern Ocean. The research also will contribute to the goals of the international research programs ICED (Integrated Climate and Ecosystem Dynamics) and GEOTRACES (Biogeochemical cycling and trace elements in the marine environment).
9909367 Leventer This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a multi-institutional, international (US - Australia) marine geologic and geophysical investigation of Prydz Bay and the MacRobertson Shelf, to be completed during an approximately 60-day cruise aboard the RVIB N.B. Palmer. The primary objective is to develop a record of climate and oceanographic change during the Quaternary, using sediment cores collected via kasten and jumbo piston coring. Core sites will be selected based on seismic profiling (Seabeam 2112 and Bathy2000). Recognition of the central role of the Antarctic Ice Sheet to global oceanic and atmospheric systems is based primarily on data collected along the West Antarctic margin, while similar extensive and high resolution data sets from the much more extensive East Antarctic margin are sparse. Goals of this project include (1) development of a century- to millennial-scale record of Holocene paleoenvironments, and (2) testing of hypotheses concerning the sedimentary record of previous glacial and interglacial events on the shelf, and evaluation of the timing and extent of maximum glaciation along this 500 km stretch of the East Antarctic margin. High-resolution seismic mapping and coring of sediments deposited in inner shelf depressions will be used to reconstruct Holocene paleoenvironments. In similar depositional settings in the Antarctic Peninsula and Ross Sea, sedimentary records demonstrate millennial- and century- scale variability in primary production and sea-ice extent during the Holocene, which have been linked to chronological periodicities in radiocarbon distribution, suggesting the possible role of solar variability in driving some changes in Holocene climate. Similar high-resolution Holocene records from the East Antarctic margin will be used to develop a circum-Antarctic suite of data regarding the response of southern glacial and oceanographic systems to late Quaternary climate change. In addition, these data will help us to evaluate the response of the East Antarctic margin to global warming. Initial surveys of the Prydz Channel - Amery Depression region reveal sequences deposited during previous Pleistocene interglacials. The upper Holocene and lower (undated) siliceous units can be traced over 15,000 km2 of the Prydz Channel, but more sub-bottom seismic reflection profiling in conjunction with dense coring over this region is needed to define the spatial distribution and extent of the units. Chronological work will determine the timing and duration of previous periods of glacial marine sedimentation on the East Antarctic margin during the late Pleistocene. Analyses will focus on detailed sedimentologic, geochemical, micropaleontological, and paleomagnetic techniques. This multi-parameter approach is the most effective way to extract a valuable paleoenvironmental signal in these glacial marine sediments. These results are expected to lead to a significant advance in understanding of the behavior of the Antarctic ice-sheet and ocean system in the recent geologic past. The combination of investigators, all with many years of experience working in high latitude marine settings, will provide an effective team to complete the project. University and College faculty (Principal Investigators on this project) will supervise a combination of undergraduate and post-graduate students involved in all stages of the project so that educational objectives will be met in tandem with the research goals of the project.
IPY: Shedding dynamic light on iron limitation: The interplay of iron<br/>limitation and dynamic irradiance in governing the phytoplankton<br/>distribution in the Ross Sea<br/><br/>The Southern Ocean plays an important role in the global carbon cycle, accounting for approximately 25% of total anthropogenic CO2 uptake by the oceans, mainly via primary production. In the Ross Sea, primary production is dominated by two taxa that are distinct in location and timing. Diatoms dominate in the shallow mixed layer of the continental shelf, whereas the colony forming Phaeocystis antarctica (Prymnesiophyceae) dominate in the more deeply mixed, open regions. Significantly, both groups have vastly different nutrient utilization characteristics, and support very different marine food webs. Their responses to climate change, and the implications for carbon export, are unclear. Previous studies show that light availability and the quality of the light climate (static versus dynamic) play a major role in defining where and when the different phytoplankton taxa bloom. However, iron (Fe) limitation of the algal communities in both the sub-Arctic and the Southern Ocean is now well documented. Moreover, phytoplankton Fe demand varies as a function of irradiance. The main hypothesis of the proposed research is: The interaction between Fe limitation and dynamic irradiance governs phytoplankton distributions in the Ross Sea. Our strategy to test this hypothesis is three-fold: 1) The photoacclimation of the different phytoplankton taxa to different light conditions under Fe limitation will be investigated in experiments in the laboratory under controlled Fe conditions. 2) The photophysiological mechanisms found in these laboratory experiments will then be tested in the field on two cruises with international IPY partners. 3) Finally, data generated during the lab and field parts of the project will be used to parameterize a dynamic light component of the Coupled Ice Atmosphere and Ocean (CIAO) model of the Ross Sea. Using the improved model, we will run future climate scenarios to test the impact of climate change on the phytoplankton community structure, distribution, primary production and carbon export in the Southern Ocean. The proposed research complies with IPY theme" Understanding Environmental change in Polar Regions" and includes participation in an international cruise. Detailed model descriptions and all of the results generated from these studies will be made public via a DynaLiFe website. Improving the CIAO model will give us and other IPY partners the opportunity to test the ecological consequences of physiological characteristics observed in Antarctic phytoplankton under current and future climate scenarios. Outreach will include participation in Stanford's Summer Program for Professional Development for Science Teachers, Stanford's School of Earth Sciences high school internship program, and development of curriculum for local science training centers, including the Chabot Space and Science Center.
Atmospheric warming has been associated with retreating glaciers, disintegrating ice shelves, and the increasing prevalence of icebergs in the Southern Ocean over the last decade. Our preliminary study of two icebergs in the NW Weddell Sea, an area of high iceberg concentration, showed significant delivery of terrestrial material accompanied by significant enhancement of phytoplankton and zooplankton/micronekton abundance, and primary production surrounding the icebergs. We hypothesize that nutrient enrichment by free-drifting icebergs will increase primary production and sedimentation of organic carbon, thus increasing the draw-down and sequestration of CO2 in the Southern Ocean and impacting the global carbon cycle. Our research addresses the following questions:1) What is the relationship between the physical dynamics of free-drifting icebergs and the Fe and nutrient distributions of the surrounding water column? 2) What is the relationship between Fe and nutrient distributions associated with free-drifting icebergs and the organic carbon dynamics of the ice-attached and surrounding pelagic communities (microbes, zooplankton, micronekton)? 3) What is impact on the export flux of particulate organic carbon from the mixed layer? An interdisciplinary approach is proposed to examine iceberg structure and dynamics, biogeochemical processes, and carbon cycling that includes measurement of trace element, nutrient and radionuclide distributions; organic carbon dynamics mediated by microbial, ice-attached and zooplankton communities; and particulate organic carbon export fluxes. Results from this project will further our understanding of the relationship between climate change and carbon sequestration in the Southern Ocean. Our findings will be incorporated into the Antarctic Research division of the Ocean Exploration Center (OEC) as part of the SIOExplorer: Digital Library Project. The OEC allows users to access content, which is classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. Graduate students, undergraduates, teachers, and volunteers are important participants in the proposed field and laboratory work. For the K-12 level, a professional writer of children's books will participate in cruises to produce an account of the expedition and a daily interactive website.
Atmospheric warming has been associated with retreating glaciers, disintegrating ice shelves, and the increasing prevalence of icebergs in the Southern Ocean over the last decade. Our preliminary study of two icebergs in the NW Weddell Sea, an area of high iceberg concentration, showed significant delivery of terrestrial material accompanied by significant enhancement of phytoplankton and zooplankton/micronekton abundance, and primary production surrounding the icebergs. We hypothesize that nutrient enrichment by free-drifting icebergs will increase primary production and sedimentation of organic carbon, thus increasing the draw-down and sequestration of CO2 in the Southern Ocean and impacting the global carbon cycle. Our research addresses the following questions:1) What is the relationship between the physical dynamics of free-drifting icebergs and the Fe and nutrient distributions of the surrounding water column? 2) What is the relationship between Fe and nutrient distributions associated with free-drifting icebergs and the organic carbon dynamics of the ice-attached and surrounding pelagic communities (microbes, zooplankton, micronekton)? 3) What is impact on the export flux of particulate organic carbon from the mixed layer? An interdisciplinary approach is proposed to examine iceberg structure and dynamics, biogeochemical processes, and carbon cycling that includes measurement of trace element, nutrient and radionuclide distributions; organic carbon dynamics mediated by microbial, ice-attached and zooplankton communities; and particulate organic carbon export fluxes. Results from this project will further our understanding of the relationship between climate change and carbon sequestration in the Southern Ocean. Our findings will be incorporated into the Antarctic Research division of the Ocean Exploration Center (OEC) as part of the SIOExplorer: Digital Library Project. The OEC allows users to access content, which is classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. Graduate students, undergraduates, teachers, and volunteers are important participants in the proposed field and laboratory work. For the K-12 level, a professional writer of children's books will participate in cruises to produce an account of the expedition and a daily interactive website.
9727077 SMITH The annual expansion and contraction of ice cover in the Southern Ocean is the largest seasonal process in the World Ocean. This seasonal variability in ice cover creates extensive fluctuations in primary production, which heavily impacts pelagic and benthic communities. This research will initiate a long time-series study of the water column and sea floor using long-term, autonomous monitoring and sampling systems developed for use in the Antarctic. The study will be located in Post Foster, Deception Island, which supports a pelagic and benthic fauna representative of the Antarctic coastal zone and experiences seasonal ice cover. A bottom-moored, upward-looking acoustic instrument will be deployed on the sea floor for a period of one year to monitor the vertical distribution, abundance and biomass of acoustically-detectable macrozooplankton and micronekton in the water column. Collections will be made over this period using a newly-developed vertically-profiling pump sampling. Simultaneously, a time-lapse camera system will be moored on the sea floor to monitor the spatial distribution, sizes and movements of the epibenthic megafauna component of the benthic community. The instrumentation development will allow the research project to focus on the effect of the seasonal sea ice cycle on the distribution, abundance and biomass of the macrozooplankton and micronekton in the water column. Similar questions on the distribution, abundance, size and movements of the epibenthic megafauna will be addressed. Results from this study will provide a valuable data base for the evaluation of the pelagic and benthic community responses to seasonal variability in the Southern Ocean.
This project seeks to examine the importance of icebergs to the pelagic ecosystem of the North-West Weddell Sea. Atmospheric warming has been associated with retreating glaciers and the increasing prevalence of icebergs in the Southern Ocean over the last decade. The highest concentration of icebergs occurs in the NW Weddell Sea, where they drift in a clockwise pattern to the northeast, following the contours of the Antarctic Peninsula through an area dubbed "Iceberg Alley". Little is known about the impact of free-drifting icebergs on the pelagic ecosystem of the Weddell Sea or on the Southern Ocean as a whole. It is hypothesized that as drifting islands, icebergs of small to intermediate size (< 10 km in largest dimension) impart unique physical, chemical and biological characteristics to the surrounding water. Three general questions will be asked to address this hypothesis: 1) What are the dynamics (approximate size, abundance and spatial distribution) of free-drifting icebergs on temporal scales of days to months, based on correlation of field measurements with imagery derived from satellite sensors? 2) What is the relationship between the size of free-drifting icebergs and the structure of the associated pelagic communities? 3) What is the estimated combined impact of free-drifting icebergs in the NW Weddell Sea on the biological characteristics of the pelagic zone? This interdisciplinary study will use standard oceanographic sampling coupled with unique methodology for staging shipboard data from all types of sensors and survey methods to determine the sphere of influence for a diverse set of biological factors as a function of iceberg size. The exploratory research proposed here will provide critical data on the effects of atmospheric warming in the Antarctic Peninsula region. The recent prevalence of free drifting icebergs in the Southern Ocean should have a pronounced enrichment effect on the surrounding pelagic ecosystem, altering community dynamics. Enhanced primary production associated with these icebergs could influence the global carbon cycle since the Southern Ocean is considered a major sink for excess CO2 from the atmosphere. <br/>The proposed research will include an innovative education component through the Ocean Exploration Center (OEC), whose focus is to provide a comprehensive view of the oceans, intelligible to non-scientists and researchers alike, with direct access to state-of-the-art databases and selected websites. The OEC will allow users to access content which has been classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. The results from this iceberg project will be incorporated into the Antarctic Research division of the OEC, providing databases documenting the impact of free-drifting icebergs on the surrounding pelagic ecosystem. These data then will be extrapolated to evaluate the impact of icebergs on the ecosystem of the Weddell Sea. Graduate students, undergraduates, teachers and volunteers are an important part of the proposed field and laboratory work.
The U.S. Global Ocean Ecosystems Dynamics (U.S. GLOBEC) program has the goal of understanding and ultimately predicting how populations of marine animal species respond to natural and anthropogenic changes in climate. Research in the Southern Ocean (SO) indicates strong coupling between climatic processes and ecosystem dynamics via the annual formation and destruction of sea ice. The Southern Ocean GLOBEC Program (SO GLOBEC) will investigate the dynamic relationship between physical processes and ecosystem responses through identification of critical parameters that affect the distribution, abundance and population dynamics of target species. The overall goals of the SO GLOBEC program are to elucidate shelf circulation processes and their effect on sea ice formation and krill distribution, and to examine the factors which govern krill survivorship and availability to higher trophic levels, including penguins, seals and whales. The focus of the U.S. contribution to the international SO GLOBEC program will be on winter processes. This component will focus on water-column primary production using direct experimental estimates, modeling restuls from a fast repetition rate fluorometer and modeling of primary production from both optical as well as biophysical models. This research will be coordinated with components focused on sea ice production and sea ice habitat. The result of the integrated SO GLOBEC program will be to improve the predictability of living marine resources, especially with respect to local and global climatic shifts.
OPP98-15823 P.I. Craig Smith<br/>OPP98-16049 P.I. David DeMaster<br/><br/>Primary production in Antarctic coastal waters is highly seasonal, yielding an intense pulse of biogenic particles to the continental shelf floor. This seasonal pulse may have major ramifications for carbon cycling, benthic ecology and material burial on the west Antarctic Peninsula (WAP) shelf. Thus, we propose a multii-disciplinary program to evaluate the seafloor accumulation, fate and benthic community impacts of bloom material along a transect of three stations crossing the Antarctic shelf in the Palmer LTER study area. Using a seasonal series of five cruises to our transect, we will test the following hypostheses: (1) A substantial proportion of spring/summer export production is deposited ont eh WAP shelf as phytodetritus or fecal pellets. (2) The deposited bloom production is a source of labile particulate organic carbon for benthos for an extended period of time (months). (3) Large amounts of labile bloom POC are rapidly subducted into the sediment column by the deposit-feeding and caching activities of benthos. (4) Macrobenthic detritivores sustain a rapid increase in biomass and abundance following the spring/summer particulate organic carbon pulse. To test these hypotheses, we will evaluate seabed deposition and lability of particulate organic carbon, patterns of particulate organic carbon mixing into sediments, seasonal variations in macrofaunal and megafaunal abundance, biomass and reproductive condition, and rates of particulate organic carbon and silica mineralization and accumulation in the seabed. Fluxes of biogenic materials and radionuclides into midwater particle traps will be contrasted with seabed deposition and burial rates to establish water-column and seabed preservation efficiencies for these materials. The project will substantially improve our understanding of the spring/summer production pulse on the WAP shelf and its impacts on seafloor communities and carbon cycling in Antarctic coastal systems.
This project seeks to examine the importance of icebergs to the pelagic ecosystem of the North-West Weddell Sea. Atmospheric warming has been associated with retreating glaciers and the increasing prevalence of icebergs in the Southern Ocean over the last decade. The highest concentration of icebergs occurs in the NW Weddell Sea, where they drift in a clockwise pattern to the northeast, following the contours of the Antarctic Peninsula through an area dubbed "Iceberg Alley". Little is known about the impact of free-drifting icebergs on the pelagic ecosystem of the Weddell Sea or on the Southern Ocean as a whole. It is hypothesized that as drifting islands, icebergs of small to intermediate size (< 10 km in largest dimension) impart unique physical, chemical and biological characteristics to the surrounding water. Three general questions will be asked to address this hypothesis: 1) What are the dynamics (approximate size, abundance and spatial distribution) of free-drifting icebergs on temporal scales of days to months, based on correlation of field measurements with imagery derived from satellite sensors? 2) What is the relationship between the size of free-drifting icebergs and the structure of the associated pelagic communities? 3) What is the estimated combined impact of free-drifting icebergs in the NW Weddell Sea on the biological characteristics of the pelagic zone? This interdisciplinary study will use standard oceanographic sampling coupled with unique methodology for staging shipboard data from all types of sensors and survey methods to determine the sphere of influence for a diverse set of biological factors as a function of iceberg size. The exploratory research proposed here will provide critical data on the effects of atmospheric warming in the Antarctic Peninsula region. The recent prevalence of free drifting icebergs in the Southern Ocean should have a pronounced enrichment effect on the surrounding pelagic ecosystem, altering community dynamics. Enhanced primary production associated with these icebergs could influence the global carbon cycle since the Southern Ocean is considered a major sink for excess CO2 from the atmosphere. <br/>The proposed research will include an innovative education component through the Ocean Exploration Center (OEC), whose focus is to provide a comprehensive view of the oceans, intelligible to non-scientists and researchers alike, with direct access to state-of-the-art databases and selected websites. The OEC will allow users to access content which has been classified to one of four levels: entry (grade K-6), student (grade 6-12), college, and research. The results from this iceberg project will be incorporated into the Antarctic Research division of the OEC, providing databases documenting the impact of free-drifting icebergs on the surrounding pelagic ecosystem. These data then will be extrapolated to evaluate the impact of icebergs on the ecosystem of the Weddell Sea. Graduate students, undergraduates, teachers and volunteers are an important part of the proposed field and laboratory work.
OPP98-15823 P.I. Craig Smith OPP98-16049 P.I. David DeMaster Primary production in Antarctic coastal waters is highly seasonal, yielding an intense pulse of biogenic particles to the continental shelf floor. This seasonal pulse may have major ramifications for carbon cycling, benthic ecology and material burial on the west Antarctic Peninsula (WAP) shelf. Thus, we propose a multii-disciplinary program to evaluate the seafloor accumulation, fate and benthic community impacts of bloom material along a transect of three stations crossing the Antarctic shelf in the Palmer LTER study area. Using a seasonal series of five cruises to our transect, we will test the following hypostheses: (1) A substantial proportion of spring/summer export production is deposited ont eh WAP shelf as phytodetritus or fecal pellets. (2) The deposited bloom production is a source of labile particulate organic carbon for benthos for an extended period of time (months). (3) Large amounts of labile bloom POC are rapidly subducted into the sediment column by the deposit-feeding and caching activities of benthos. (4) Macrobenthic detritivores sustain a rapid increase in biomass and abundance following the spring/summer particulate organic carbon pulse. To test these hypotheses, we will evaluate seabed deposition and lability of particulate organic carbon, patterns of particulate organic carbon mixing into sediments, seasonal variations in macrofaunal and megafaunal abundance, biomass and reproductive condition, and rates of particulate organic carbon and silica mineralization and accumulation in the seabed. Fluxes of biogenic materials and radionuclides into midwater particle traps will be contrasted with seabed deposition and burial rates to establish water-column and seabed preservation efficiencies for these materials. The project will substantially improve our understanding of the spring/summer production pulse on the WAP shelf and its impacts on seafloor communities and carbon cycling in Antarctic coastal systems.
This project is an interdisciplinary study, titled Research on Ocean-Atmosphere Variability and Ecosystem Response in the Ross Sea (ROAVERRS), of atmospheric forcing, ocean hydrography, sea ice dynamics, primary productivity, and pelagic-benthic coupling in the southwestern Ross Sea, Antarctica. The primary goal is to examine how changes in aspects of the polar climate system, in this case wind and temperature, combine to influence marine productivity on a large antarctic continental shelf. In the Ross Sea, katabatic winds and mesocyclones influence the spatial and temporal distribution of sea ice as well as the upper ocean mixed layer depth, and thus control primary production within the sea ice as well as in the open water system. The structure, standing stock and productivity of bottom- dwelling biological communities are also linked to meteorological processes through interseasonal and interannual variations in horizontal and vertical fluxes of organic carbon produced in the upper ocean. Linkages among the atmospheric, oceanic, and biological systems will be investigated during a three-year field study of the southwestern Ross Sea ecosystem. Direct measurements will include regional wind and air temperatures derived from automatic weather stations; ice cover, ice movement, and sea surface temperatures derived from a variety of satellite-based sensors; hydrographic characteristics of the upper ocean and primary productivity in the ice and in the water derived from research cruises and satellite studies; vertical flux of organic material and water movement derived from oceanographic moorings containing sediment traps and current meters, and the abundance, distribution, and respiration rates of biological communities on the sea floor, derived from box cores, benthic photographs and shipboard incubations. Based on archived meteorological data, it is expected that the atmospheric variability during the study period will be such that changes in airflow pat terns and their influence on oceanographic and biological patterns can be monitored, and their direct and indirect linkages that are the focus of the research can be deduced. Results from this study will contribute to our knowledge of atmospheric and oceanic forcing of marine ecosystems, and lead to a better understanding of marine ecosystem response to climatic variations. ***
The annual advance and retreat of pack ice may be the major physical determinant of spatial/temporal changes in the structure and function of antarctic marine communities. Interannual cycles and/or trends in the annual extent of pack ice may also have significant effects on all levels of the food web, from total annual primary production to breeding success in seabirds. Historical records indicate a 6 to 8 year cycle in the maximum extent of pack ice in the winter. During this decade winters were colder in 1980 and 1981, and again in 1986 and 1987. In order to understand the interactions between pack ice and ecosystem dynamics, especially the influences of the well- documented interannual variability in ice cover on representative populations, a long-term ecological research (LTER) site has been established in the Antarctic Peninsula region near Palmer Station. The LTER project, will conduct comprehensive measurements of ice-dominated ecosystems in this region with a focus on primary production, krill populations and swarms and seabirds. A primary emphasis will be placed on the development of ecosystem models that will provide a predictive capability for issues related to global environmental change. This proposal will add to the existing LTER project detailed studies of the biogeochemical cycling of carbon and associated bioelements. The microbiology and carbon flux component of LTER will provide measurements of a suite of core parameters relevant to the carbon cycle and will test several hypotheses pertaining to carbon flux, including bacterial productivity and nutrient regeneration.
The annual advance and retreat of pack ice may be the major physical determinant of spatial and temporal changes in the structure and function of antarctic marine communities. Interannual cycles and/or trends in the annual extent of pack ice may also have significant effects on all levels of the food web, from total annual primary production to breeding success in seabirds. Historical records indicate a six to eight year cycle in the maximum extent of pack ice in the winter. During this decade, winters were colder in 1980 and 1981, and again in 1986 and 1987. Winter-over survival in Adelie penguins varied on the same cycle, higher in winters with heavy pack ice. This Long Term Ecological Research (LTER) project will define ecological processes linking the extent of annual pack ice with the biological dynamics of different trophic levels within antarctic marine communities. The general focus is on interannual variability in representative populations from the antarctic marine food web and on mechanistic linkages that control the observed variability in order to develop broader generalizations applicable to other large marine environments. To achieve these objectives, data from several spatial and temporal scales, including remote sensing, a field approach that includes an annual monitoring program, a series of process-oriented research cruises, and a modeling effort to provide linkages on multiple spatial and temporal scales between biological and environmental components of the ecosystem will be employed.
Neale 9615342 Increases in ultraviolet-B radiation (UV-B, 280-320) associated with the Antarctic ozone hole have been shown to inhibit the photosynthesis of phytoplankton, but the overall effect on water column production is still a matter of debate and continued investigation. Investigations have also revealed that even at "normal" levels of Antarctic stratospheric ozone, UV-B and UV-A (320-400 nm) appear to have strong effects on water column production. The role of UV in the ecology of phytoplankton primary production has probably been underappreciated in the past and could be particularly important to the estimation of primary production in the presence of vertical mixing. This research focuses on quantifying UV effects on photosynthesis of Antarctic phytoplankton by defining biological weighting functions for UV-inhibition. In the past, techniques were developed to describe photosynthesis as a function of UV and visible irradiance using laboratory cultures. Further experimentation with natural assemblages from McMurdo Station in Antarctica showed that biological weighting functions are strongly related to light history. Most recently, measurements in the open waters of the Southern Ocean confirmed that there is substantial variability in the susceptibility of phytoplankton assemblages to UV. It was also discovered that inhibition of photosynthesis in Antarctic phytoplankton got progressively worse on the time scale of hours, with no evidence of recovery. Even under benign conditions, losses of photosynthetic capability persisted unchanged for several hours. This was in contrast with laboratory cultures and some natural assemblages which quickly attained a steady- state rate of photosynthesis during exposure to UV, reflecting a balance between damage and recovery processes. Slow reversal of UV-induced damage has profound consequences for water-column photosynthesis, especially during vertical mixing. Results to date have been used to model th e influence of UV, ozone depletion and vertical mixing on photosynthesis in Antarctic waters. Data indicate that normal levels of UV can have a significant impact on natural phytoplankton and that the effects can be exacerbated by ozone depletion as well as vertical mixing. Critical questions remain poorly resolved, however, and these are the focus of the present proposal. New theoretical and experimental approaches will be used to investigate UV responses in both the open waters of the Weddell-Scotia confluence and coastal waters near Palmer Station. In particular, measurements will be made of the kinetics of UV inhibition and recovery on time scales ranging from minutes to days. Variability in biological weighting functions between will be calculated for pelagic and coastal phytoplankton in the Southern Ocean. The results will provide absolute estimates of photosynthesis under in situ, as well as under altered, UV irradiance; broaden the range of assemblages for which biological weighting functions have been determined; and clarify how kinetics of inhibition and recovery should be represented in mixed layer models.
Increases in middle ultraviolet radiation associated with the Antarctic ozone hole have been shown to inhibit the photosynthesis of phytoplankton, and results have been extrapolated to estimate the effect of ozone depletion on primary productivity in the marginal ice zone. This research will refine the assessment by specifying detailed wavelength-dependent biological weighting functions for the inhibition of photosynthesis by ultraviolet radiation, and by considering the mitigating effects of vertical mixing. Biological weighting functions of phytoplankton in the marginal ice zone will be measured under controlled conditions and applied in a new model of photosynthesis to predict primary productivity in situ, as well as under altered ultraviolet irradiance. These predictions will be compared with observations on samples from the water column and with measurements during incubations of several hours under different irradiance regimes. Results of these comparisons will be used to test the model and to quantify the potential artifact of long incubations. Assumptions about the kinetics of photoinhibition and recovery, critical to modeling the effects of vertical mixing, will be examined with time-course experiments. Results will be incorporated into a model of photosynthesis and photoinhibition in the water column that will be used to predict the influence of ozone depletion on marine primary production, particularly in the marginal zone.
Abstract<br/><br/>The research will continue and extend the study in the Southern Ocean that was initiated during the Oden Southern Ocean 2006 expedition in collaboration with Swedish scientist Mellissa Chierici. We will quantify carbon flux through the food web in the marginal ice zone (MIZ) by measuring size fractionated primary and secondary production, grazing and carbon flux through nanoplankton (2-20 um), microplankton (20-200um), and mesoplankton (200-2000 um). Community structure, species abundance and size specific grazing rates will be quantified using a variety of techniques both underway and at ice stations along the MIZ. The proposed cruise track extends across the Drake Passage to the Western Antarctic Peninsula (WAP) with three station transects along a gradient from the open ocean through the marginal ice zone (MIZ) in the Bellinghausen and Amundsen Seas and into the Ross Sea Polynya. Ice stations along each transect will provide material to characterize production associated with annual ice. Underway measurements of primary and secondary production (chlorophyll, CDOM, microplankton, and mesoplankton) and hydrography (temperature, salinity, pH, DO, turbidity) will establish a baseline for future cruises and as support for other projects such as biogeochemical studies on carbon dioxide drawdown and trace metal work on primary production. The outcome of these measurements will be a description of nano to mesoplankton standing stocks, community structure, and carbon flux along the MIZ in the Bellinghausen and Amundsen Seas and the Ross Sea Polynya.
Denitrification is the main process by which fixed nitrogen is lost from ecosystems and the regulation of this process may directly affect primary production and carbon cycling over short and long time scales. Previous investigations of the role of bioactive metals in regulating denitrification in bacteria from permanently ice-covered Lake Bonney in the Taylor Valley of East Antarctica indicated that denitrifying bacteria can be negatively affected by metals such as copper, iron, cadmium, lead, chromium, nickel, silver and zinc; and that there is a distinct difference in denitrifying activity between the east and west lobes of the lake. Low iron concentrations were found to exacerbate the potential toxicity of the other metals, while silver has the potential to specifically inhibit denitrification because of its ability to interfere with copper binding in redox proteins, such as nitrite reductase and nitrous oxide reductase. High silver concentrations might prevent the functioning of nitrous oxide reductase in the same way that simple copper limitation does, thereby causing the buildup of nitrous oxide and resulting in a nonfunctional nitrogen cycle. Other factors, such as oxygen concentration, are likely also to affect bacterial activity in Lake Bonney. This project will investigate silver toxicity, general metal toxicity and oxygen concentration to determine their effect on denitrification in the lake by using a suite of "sentinel" strains of denitrifying bacteria (isolated from the lake) incubated in Lake Bonney water and subjected to various treatments. The physiological responses of these strains to changes in metal and oxygen concentration will be quantified by flow cytometric detection of single cell molecular probes whose sensitivity and interpretation have been optimized for the sentinel strains. Understanding the relationships between metals and denitrification is expected to enhance our understanding of not only Lake Bonney's unusual nitrogen cycle, but more generally, of the potential role of metals in the regulation of microbial nitrogen transformations.<br/><br/>The broader impacts of this work include not only a better understanding of regional biogeochemistry and global perspectives on these processes; but also the training of graduate students and a substantial outreach effort for school children.
The Shackleton Fracture Zone (SFZ) in the Drake Passage defines a boundary between low and high phytoplankton waters. West of Drake Passage, Southern Ocean waters south of the Polar Front and north of the Antarctic continent shelf have very low satellite-derived surface chlorophyll concentrations. Chlorophyll and mesoscale eddy kinetic energy are higher east of SFZ compared to values west of the ridge. In situ data from a 10-year survey of the region as part of the National Marine Fisheries Service's Antarctic Marine Living Resources program confirm the existence of a strong hydrographic and chlorophyll gradient in the region. An interdisciplinary team of scientists hypothesizes that bathymetry, including the 2000 m deep SFZ, influences mesoscale circulation and transport of iron leading to the observed phytoplankton patterns. To address this<br/>hypothesis, the team proposes to examine phytoplankton and bacterial physiological states (including responses to iron enrichment) and structure of the plankton communities from virus to zooplankton, the concentration and distribution of Fe, Mn, and Al, and mesoscale flow patterns near the SFZ. Relationships between iron concentrations and phytoplankton characteristics will be examined in the context of the mesoscale transport of trace nutrients to determine how much of the observed variability in phytoplankton biomass can be attributed to iron supply, and to determine the most important sources of iron to pelagic waters east of the Drake Passage. The goal is to better understand how plankton productivity and community structure in the Southern Ocean are affected by the coupling between bathymetry, mesoscale circulation, and limiting nutrient distributions.<br/><br/>The research program includes rapid surface surveys of chemical, plankton, and hydrographic properties complemented by a mesoscale station grid for vertical profiles, water sampling, and bottle incubation enrichment experiments. Distributions of manganese and aluminum will be determined to help distinguish aeolian, continental shelf and upwelling sources of iron. The physiological state of the phytoplankton will be monitored by active fluorescence methods sensitive to the effects of iron limitation. Mass concentrations of pigment, carbon and nitrogen will be obtained by analysis of filtered samples, cell size distributions by flow cytometry, and species identification by microscopy. Primary production and photosynthesis parameters (absorption, quantum yields, variable fluorescence) will be measured on depth profiles, during surface surveys and on bulk samples from enrichment experiments. Viruses and bacteria will be examined for abundances, and bacterial production will be assessed in terms of whether it is limited by either iron or organic carbon sources. The proposed work will improve our understanding of processes controlling distributions of iron and the response of plankton communities in the Southern Ocean. This proposal also includes an outreach component comprised of Research Experiences for Undergraduates (REU), Teachers Experiencing the Antarctic and Arctic (TEA), and the creation of an educational website and K-12 curricular modules based on the project.