{"dp_type": "Project", "free_text": "West Antarctic Shelf"}
[{"awards": "2026045 Schofield, Oscar; 2224611 Schofield, Oscar", "bounds_geometry": "POLYGON((-79.65 -63.738,-77.9728 -63.738,-76.29560000000001 -63.738,-74.61840000000001 -63.738,-72.94120000000001 -63.738,-71.26400000000001 -63.738,-69.58680000000001 -63.738,-67.9096 -63.738,-66.2324 -63.738,-64.5552 -63.738,-62.878 -63.738,-62.878 -64.3683,-62.878 -64.9986,-62.878 -65.6289,-62.878 -66.25919999999999,-62.878 -66.8895,-62.878 -67.5198,-62.878 -68.1501,-62.878 -68.7804,-62.878 -69.41069999999999,-62.878 -70.041,-64.5552 -70.041,-66.2324 -70.041,-67.9096 -70.041,-69.5868 -70.041,-71.26400000000001 -70.041,-72.94120000000001 -70.041,-74.61840000000001 -70.041,-76.29560000000001 -70.041,-77.9728 -70.041,-79.65 -70.041,-79.65 -69.41069999999999,-79.65 -68.7804,-79.65 -68.1501,-79.65 -67.5198,-79.65 -66.8895,-79.65 -66.25919999999999,-79.65 -65.6289,-79.65 -64.9986,-79.65 -64.3683,-79.65 -63.738))", "dataset_titles": "Expedition Data of LMG2301; Expedition Data of NBP2113; Palmer LTER data in the Environmental Data Initiative Repository", "datasets": [{"dataset_uid": "200370", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of NBP2113", "url": "https://www.rvdata.us/search/cruise/NBP2113"}, {"dataset_uid": "200367", "doi": "", "keywords": null, "people": null, "repository": "EDI", "science_program": null, "title": "Palmer LTER data in the Environmental Data Initiative Repository", "url": "https://portal.edirepository.org/nis/browseServlet?searchValue=PAL"}, {"dataset_uid": "200371", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data of LMG2301", "url": "https://www.rvdata.us/search/cruise/LMG2301"}], "date_created": "Wed, 26 Jul 2023 00:00:00 GMT", "description": "Part 1: Non-technical description The goal of all LTER sites is to conduct policy-relevant ecosystem research for questions that require tens of years of data and cover large geographical areas. The Palmer Antarctica Long Term Ecological Research (PAL-LTER) site has been in operation since 1990 and has been studying how the marine ecosystem west of the Antarctica Peninsula (WAP) is responding to a climate that is changing as rapidly as any place on the Earth. The study is evaluating how warming conditions and decreased ice cover leading to extended periods of open water are affecting many aspects of ecosystem function. The team is using combined cutting-edge approaches including yearly ship-based research cruises, small-boat weekly sampling, autonomous vehicles, animal biologging, oceanographic floats and seafloor moorings, manipulative lab-based process studies and modeling to evaluate both seasonal and annual ecosystem responses. These combined approaches are allowing for the study the ecosystem changes at scales needed to assess both short-term and long-term drivers. The study region also includes submarine canyons that are special regions of enhanced biological activity within the WAP. This research program is paired with a comprehensive education and outreach program promoting the global significance of Antarctic science and research. In addition to training for graduate and undergraduate students, they are using newly-developed Polar Literacy Principles as a foundation in a virtual schoolyard program that shares polar instructional materials and provides learning opportunities for K-12 educators. The PAL-LTER team is also leveraging the development of Out of School Time materials for afterschool and summer camp programs, sharing Palmer LTER-specific teaching materials with University, Museum, and 4-H Special Interest Club partners. Part 2: Technical description Polar ecosystems are among the most rapidly changing on Earth. The Palmer LTER (PAL-LTER) program builds on three decades of coordinated research along the western side of the Antarctic Peninsula (WAP) to gain new mechanistic and predictive understanding of ecosystem changes in response to disturbances spanning long-term decadal (\u2018press\u2019) drivers and changes due to higher-frequency (\u2018pulse\u2019) drivers, such as large storms and extreme seasonal anomaly in sea ice cover. The influence of major natural climate modes that modulate variations in sea ice, weather, and oceanographic conditions to drive changes in ecosystem structure and function (e.g., El Ni\u00f1o Southern Oscillation and Southern Annular Mode) are being studied at multiple time scales \u2013from diel, seasonal, interannual, to decadal intervals, and space scales\u2013from hemispheric to global scale investigated by remote sensing, the regional scales. Specifically, the team is evaluating how variability of physical properties (such as vertical and alongshore connectivity processes) interact to modulate biogeochemical cycling and community ecology in the WAP region. The study is providing an evaluation of ecosystem resilience and ecological responses to long-term \u201cpress-pulse\u201d drivers and a decadal-level reversal in sea ice coverage. This program is providing fundamental understanding of population and biogeochemical responses for a marine ecosystem experiencing profound change. 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": -62.878, "geometry": "POINT(-71.26400000000001 -66.8895)", "instruments": null, "is_usap_dc": true, "keywords": "SEA ICE; PLANKTON; PELAGIC; West Antarctic Shelf; R/V NBP; OCEAN MIXED LAYER; COMMUNITY DYNAMICS; PENGUINS; R/V LMG", "locations": "West Antarctic Shelf", "north": -63.738, "nsf_funding_programs": "Antarctic Integrated System Science; Antarctic Integrated System Science", "paleo_time": null, "persons": "Schofield, Oscar; Steinberg, Deborah", "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": "EDI; R2R", "science_programs": "LTER", "south": -70.041, "title": "LTER: Ecological Response and Resilience to \u201cPress-Pulse\u201d Disturbances and a Recent Decadal Reversal in Sea Ice Trends Along the West Antarctic Peninsula", "uid": "p0010426", "west": -79.65}, {"awards": "2138277 Gallagher, Katherine", "bounds_geometry": "POLYGON((-78 -62,-76.2 -62,-74.4 -62,-72.6 -62,-70.8 -62,-69 -62,-67.2 -62,-65.4 -62,-63.6 -62,-61.8 -62,-60 -62,-60 -63,-60 -64,-60 -65,-60 -66,-60 -67,-60 -68,-60 -69,-60 -70,-60 -71,-60 -72,-61.8 -72,-63.6 -72,-65.4 -72,-67.2 -72,-69 -72,-70.8 -72,-72.6 -72,-74.4 -72,-76.2 -72,-78 -72,-78 -71,-78 -70,-78 -69,-78 -68,-78 -67,-78 -66,-78 -65,-78 -64,-78 -63,-78 -62))", "dataset_titles": "Current velocity and direction data from Regional Ocean Modeling System simulations (2006-2007 \u0026 2010-2011); Current velocity and direction data from Regional Ocean Modeling System simulations (2008-2009 \u0026 2018-2019); Passive particle trajectories from Regional Ocean Modeling System simulations 2008-2009 \u0026 2018-2019; Simulated krill trajectory data from Regional Ocean Modeling System simulations 2006-2007 \u0026 2010-2011; Simulated krill trajectory data from Regional Ocean Modeling System simulations 2008-2009 \u0026 2018-2019; Simulated marine debris trajectories along the West Antarctic Peninsula in 2008-2009 and 2018-2019", "datasets": [{"dataset_uid": "601734", "doi": "10.15784/601734", "keywords": "Antarctica; Modeling; Regional Ocean Modeling System; West Antarctic Shelf", "people": "Gallagher, Katherine", "repository": "USAP-DC", "science_program": null, "title": "Simulated marine debris trajectories along the West Antarctic Peninsula in 2008-2009 and 2018-2019", "url": "https://www.usap-dc.org/view/dataset/601734"}, {"dataset_uid": "601655", "doi": "10.15784/601655", "keywords": "Antarctica; Antarctic Krill; Model Data; Physical Oceanography; Regional Ocean Modeling System; ROMS; West Antarctic Shelf", "people": "Gallagher, Katherine", "repository": "USAP-DC", "science_program": null, "title": "Simulated krill trajectory data from Regional Ocean Modeling System simulations 2008-2009 \u0026 2018-2019", "url": "https://www.usap-dc.org/view/dataset/601655"}, {"dataset_uid": "601682", "doi": "10.15784/601682", "keywords": "Antarctica; Physical Oceanography; Regional Ocean Modeling System; ROMS", "people": "Gallagher, Katherine", "repository": "USAP-DC", "science_program": null, "title": "Passive particle trajectories from Regional Ocean Modeling System simulations 2008-2009 \u0026 2018-2019", "url": "https://www.usap-dc.org/view/dataset/601682"}, {"dataset_uid": "601656", "doi": "10.15784/601656", "keywords": "Antarctica; Model Data; Ocean Currents; Physical Oceanography; Regional Ocean Modeling System; ROMS; West Antarctic Shelf", "people": "Gallagher, Katherine", "repository": "USAP-DC", "science_program": null, "title": "Current velocity and direction data from Regional Ocean Modeling System simulations (2008-2009 \u0026 2018-2019)", "url": "https://www.usap-dc.org/view/dataset/601656"}, {"dataset_uid": "601779", "doi": "10.15784/601779", "keywords": "Antarctica; Cryosphere; Model Data; Ocean Currents; Physical Oceanography; Regional Ocean Modeling System; ROMS; West Antarctic Shelf", "people": "Gallagher, Katherine", "repository": "USAP-DC", "science_program": null, "title": "Current velocity and direction data from Regional Ocean Modeling System simulations (2006-2007 \u0026 2010-2011)", "url": "https://www.usap-dc.org/view/dataset/601779"}, {"dataset_uid": "601780", "doi": "10.15784/601780", "keywords": "Antarctica; Antarctic Krill; Cryosphere; Model Data; Physical Oceanography; Regional Ocean Modeling System; ROMS; West Antarctic Shelf", "people": "Gallagher, Katherine", "repository": "USAP-DC", "science_program": null, "title": "Simulated krill trajectory data from Regional Ocean Modeling System simulations 2006-2007 \u0026 2010-2011", "url": "https://www.usap-dc.org/view/dataset/601780"}], "date_created": "Tue, 19 Jul 2022 00:00:00 GMT", "description": "Pygoscelis penguins are central place foragers during the summer while they raise their chicks. They leave and return to the same colony location after hunting for food and rely on the availability of Antarctic krill, their primary food source. This research focuses on whether penguin diets and colony location reflect the retention of prey around and near colonies on the West Antarctic Peninsula. Eddies and other oceanographic processes may facilitate prey retention at certain locations, driving penguin colony establishment and success. This project hypothesizes that Pygoscelis penguin diets will be composed of more Antarctic krill (Euphausia superba) when local prey retention is high, possibly due to subsurface eddies. This hypothesis will be tested using satellite-based estimates of Pygoscelis penguin diet composition using multispectral sensor data to estimate nitrogen values and infer trophic level. Prey retention will be calculated along the peninsula using the Regional Ocean Modeling System (ROMS). Simulated particles and diel vertical migration will be used to mimic krill behavior. These particles can be experimentally seeded across multiple depths in multiple years to assess residence times in the system. Using penguin colony data from the Mapping Application for Penguin Populations and Projected Dynamics (MAPPPD), the PI will correlate diet and retention metrics to local penguin colony growth and persistence and build a predictive model of where colonies may form in the future. 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": -60.0, "geometry": "POINT(-69 -67)", "instruments": null, "is_usap_dc": true, "keywords": "Antarctic Peninsula; PENGUINS; SPECIES/POPULATION INTERACTIONS; OCEAN CURRENTS", "locations": "Antarctic Peninsula", "north": -62.0, "nsf_funding_programs": "Post Doc/Travel", "paleo_time": null, "persons": "Gallagher, Katherine", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -72.0, "title": "OPP-PRF Pygoscelis Penguin Response to Potential Prey Retention along the West Antarctic Peninsula", "uid": "p0010349", "west": -78.0}, {"awards": "1746087 Tarrant, Ann", "bounds_geometry": "POLYGON((-80 -60,-77.5 -60,-75 -60,-72.5 -60,-70 -60,-67.5 -60,-65 -60,-62.5 -60,-60 -60,-57.5 -60,-55 -60,-55 -61,-55 -62,-55 -63,-55 -64,-55 -65,-55 -66,-55 -67,-55 -68,-55 -69,-55 -70,-57.5 -70,-60 -70,-62.5 -70,-65 -70,-67.5 -70,-70 -70,-72.5 -70,-75 -70,-77.5 -70,-80 -70,-80 -69,-80 -68,-80 -67,-80 -66,-80 -65,-80 -64,-80 -63,-80 -62,-80 -61,-80 -60))", "dataset_titles": "Calanoides acutus: Transcriptome and gene expression data; BioProject PRJNA757455; Calanus propinquus: Transcriptome and gene expression data; BioProject PRJNA669816; Expedition data of LMG1901; Rhincalanus gigas: Transcriptome and gene expression data; BioProject PRJNA666170", "datasets": [{"dataset_uid": "200284", "doi": "", "keywords": null, "people": null, "repository": "NCBI", "science_program": null, "title": "Calanoides acutus: Transcriptome and gene expression data; BioProject PRJNA757455", "url": "https://www.ncbi.nlm.nih.gov/bioproject/?term=PRJNA757455"}, {"dataset_uid": "200125", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1901", "url": "https://www.rvdata.us/search/cruise/LMG1901"}, {"dataset_uid": "200239", "doi": "", "keywords": null, "people": null, "repository": "NCBI", "science_program": null, "title": "Rhincalanus gigas: Transcriptome and gene expression data; BioProject PRJNA666170", "url": "https://www.ncbi.nlm.nih.gov/bioproject/PRJNA666170"}, {"dataset_uid": "200283", "doi": "", "keywords": null, "people": null, "repository": "NCBI", "science_program": null, "title": "Calanus propinquus: Transcriptome and gene expression data; BioProject PRJNA669816", "url": "https://www.ncbi.nlm.nih.gov/bioproject/PRJNA669816"}], "date_created": "Fri, 06 Aug 2021 00:00:00 GMT", "description": "Animals in the polar oceans have adapted to dramatic seasonal changes in day length, food availability, and ice cover, as well as to consistently cold waters. This project focuses on the adaptations of copepods - small animals that live in the water column and are an important food source to many different predators. The field studies will take place in the western Antarctic Peninsula, an environment and ecosystem that is rapidly changing. Antarctic copepods have developed particular feeding and behavioral strategies to survive in their very seasonal environment, however it is not known how each of these species will respond to environmental change. The overall goal of this project is to examine and compare these adaptations across species and to understand how each species responds to short-term changes in food availability. The project contains three main objectives: the first objective is to compare the sets of genes across species, especially looking at genes related to storage of energy from food. The second objective is to measure and compare the responses of copepods to changes in food availability. The third objective is to determine how variation across the western Antarctic Pensinsula habitat affects the feeding condition of the copepods. To make the data more useful to the broader research community, a database will be developed enabling easy comparison of genetic information between copepod species. This project will provide hands-on training opportunities to graduate and undergraduate student and will seek to recruit students from underrepresented groups. Results and scientific concepts will be shared through outreach activities, including an expedition blog, a series of interactive animations, and public presentations. Polar marine organisms have adapted to dramatic seasonal changes in photoperiod, light intensity, and ice cover, as well as to cold but stable thermal environments. The western Antarctic Peninsula, the focal region for the field studies, has experienced rapid warming and ice melt. While it is difficult to predict exactly how physical conditions in this region will change, effects on species distributions have already been documented. Large Antarctic copepods in the families Calanidae and Rhincalanidae are dominant components of the mesozooplankton that use different metabolic and behavioral strategies to optimize their use of a highly seasonal food supply. The overall goal of this project is to leverage molecular approaches to examine the physiological and metabolic adaptations at the individual and species level. The project focuses on three main objectives: the first objective is to characterize the gene complement and stage-specific gene expression patterns in Antarctic copepods within an evolutionary context. The second objective is to measure and compare the physiological and molecular responses of juvenile copepods to variable feeding conditions. The third objective is to characterize metabolic variation within natural copepod populations. The metabolically diverse Antarctic copepods also provide an excellent opportunity to compare mechanisms regulating energy storage and utilization and to test hypotheses regarding the roles of specific genes. The field studies will aim to utilize information from an ongoing long term research program (the Palmer Long-Term Ecological Research), which complements the ongoing program and provides extensive context for this project. To make the data more useful to the research community, a database will be developed facilitating comparison of transcriptomes between copepod species. This project will provide hands-on training opportunities to graduate and undergraduate students. Efforts will be made to recruit students who are members of underrepresented minorities. Results and scientific concepts will be broadly disseminated through an expedition blog, a series of interactive animations, and public presentations. 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": -55.0, "geometry": "POINT(-67.5 -65)", "instruments": null, "is_usap_dc": true, "keywords": "ARTHROPODS; AMD; PELAGIC; USA/NSF; USAP-DC; PLANKTON; West Antarctic Shelf; Amd/Us; SHIPS", "locations": "West Antarctic Shelf", "north": -60.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Tarrant, Ann", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e SHIPS", "repo": "NCBI", "repositories": "NCBI; R2R", "science_programs": null, "south": -70.0, "title": "Physiological Ecology of \"Herbivorous\" Antarctic Copepods", "uid": "p0010239", "west": -80.0}, {"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": "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": "1551195 Burdige, David", "bounds_geometry": "POLYGON((-71 -64,-70.1 -64,-69.2 -64,-68.3 -64,-67.4 -64,-66.5 -64,-65.6 -64,-64.7 -64,-63.8 -64,-62.9 -64,-62 -64,-62 -64.4,-62 -64.8,-62 -65.2,-62 -65.6,-62 -66,-62 -66.4,-62 -66.8,-62 -67.2,-62 -67.6,-62 -68,-62.9 -68,-63.8 -68,-64.7 -68,-65.6 -68,-66.5 -68,-67.4 -68,-68.3 -68,-69.2 -68,-70.1 -68,-71 -68,-71 -67.6,-71 -67.2,-71 -66.8,-71 -66.4,-71 -66,-71 -65.6,-71 -65.2,-71 -64.8,-71 -64.4,-71 -64))", "dataset_titles": "Expedition data of NBP1601; Project: Organic Carbon Oxidation and Iron Remobilization by West Antarctic Shelf Sediments", "datasets": [{"dataset_uid": "200148", "doi": "", "keywords": null, "people": null, "repository": "BCO-DMO", "science_program": null, "title": "Project: Organic Carbon Oxidation and Iron Remobilization by West Antarctic Shelf Sediments", "url": "https://www.bco-dmo.org/project/806864"}, {"dataset_uid": "002665", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP1601", "url": "https://www.rvdata.us/search/cruise/NBP1601"}], "date_created": "Tue, 16 Jun 2020 00:00:00 GMT", "description": "General Statement: The continental shelf region west of the Antarctic Peninsula has recently undergone dramatic changes and ecosystem shifts, and the community of organisms that live in, or feed off, the sea floor sediments is being impacted by species invasions from the north. Previous studies of these sediments indicate that this community may consume much more of the regional productivity than previously estimated, suggesting that sediments are a rich and important component of this ecosystem and one that may be ripe for dramatic change. Furthermore, under richer sediment conditions, iron is mobilized and released back to the water column. Since productivity in this ecosystem is thought to be limited by the availability of iron, increased rates of iron release from these sediments could stimulate productivity and promote greater overall ecosystem change. In this research, a variety of sites across the shelf region will be sampled to accurately evaluate the role of sediments in consuming ecosystem productivity and to estimate the current level of iron release from the sediments. This project will provide a baseline set of sediment results that will present a more complete picture of the west Antarctic shelf ecosystem, will allow for comparison with water column measurements and for evaluation of the fundamental workings of this important ecosystem. This is particularly important since high latitude systems may be vulnerable to the effects of climate fluctuations. Both graduate and undergraduate students will be trained. Presentations will be made at scientific meetings, at other universities, and at outreach events. A project web site will present key results to the public and explain how this new information improves understanding of Antarctic ecosystems. Technical Description of Project: In order to determine the role of sediments within the west Antarctic shelf ecosystem, this project will determine the rates of sediment organic matter oxidation at a variety of sites across the Palmer Long Term Ecosystem Research (LTER) study region. To estimate the rates of release of iron and manganese from the sediments, these same sites will be sampled for detailed vertical distributions of the concentrations of these metals both in the porewaters and in important mineral phases. Since sediment sampling will be done at LTER sites, the sediment data can be correlated with the rich productivity data set from the LTER. In detail, the project: a) will determine the rates of oxygen consumption, organic carbon oxidation, nutrient release, and iron mobilization by shelf sediments west of the Antarctic Peninsula; b) will investigate the vertical distribution of diagenetic reactions within the sediments; and c) will assess the regional importance of these sediment rates. Sediment cores will be used to determine sediment-water fluxes of dissolved oxygen, total carbon dioxide, nutrients, and the vertical distributions of these dissolved compounds, as well as iron and manganese in the pore waters. Bulk sediment properties of porosity, organic carbon and nitrogen content, carbonate content, biogenic silica content, and multiple species of solid-phase iron, manganese, and sulfur species will also be determined. These measurements will allow determination of total organic carbon oxidation and denitrification rates, and the proportion of aerobic versus anaerobic respiration at each site. Sediment diagenetic modeling will link the processes of organic matter oxidation to metal mobilization. Pore water and solid phase iron and manganese distributions will be used to model iron diagenesis in these sediments and to estimate the iron flux from the sediments to the overlying waters. Finally, the overall regional average and distribution of the sediment processes will be compared with the distributions of seasonally averaged chlorophyll biomass and productivity.", "east": -62.0, "geometry": "POINT(-66.5 -66)", "instruments": null, "is_usap_dc": true, "keywords": "BIOGEOCHEMICAL CYCLES; Iron Remobilization; R/V NBP; NBP1601; SEDIMENT CHEMISTRY; USAP-DC; West Antarctic Shelf", "locations": "West Antarctic Shelf", "north": -64.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Burdige, David; Christensen, John", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "BCO-DMO", "repositories": "BCO-DMO; R2R", "science_programs": null, "south": -68.0, "title": "Organic carbon oxidation and iron remobilization by West Antarctic shelf sediments ", "uid": "p0010108", "west": -71.0}]
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Project Title/Abstract/Map | NSF Award(s) | Date Created | PIs / Scientists | Dataset Links and Repositories | Abstract | Bounds Geometry | Geometry | Selected | Visible | |||||||
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LTER: Ecological Response and Resilience to “Press-Pulse” Disturbances and a Recent Decadal Reversal in Sea Ice Trends Along the West Antarctic Peninsula
|
2026045 2224611 |
2023-07-26 | Schofield, Oscar; Steinberg, Deborah |
|
Part 1: Non-technical description The goal of all LTER sites is to conduct policy-relevant ecosystem research for questions that require tens of years of data and cover large geographical areas. The Palmer Antarctica Long Term Ecological Research (PAL-LTER) site has been in operation since 1990 and has been studying how the marine ecosystem west of the Antarctica Peninsula (WAP) is responding to a climate that is changing as rapidly as any place on the Earth. The study is evaluating how warming conditions and decreased ice cover leading to extended periods of open water are affecting many aspects of ecosystem function. The team is using combined cutting-edge approaches including yearly ship-based research cruises, small-boat weekly sampling, autonomous vehicles, animal biologging, oceanographic floats and seafloor moorings, manipulative lab-based process studies and modeling to evaluate both seasonal and annual ecosystem responses. These combined approaches are allowing for the study the ecosystem changes at scales needed to assess both short-term and long-term drivers. The study region also includes submarine canyons that are special regions of enhanced biological activity within the WAP. This research program is paired with a comprehensive education and outreach program promoting the global significance of Antarctic science and research. In addition to training for graduate and undergraduate students, they are using newly-developed Polar Literacy Principles as a foundation in a virtual schoolyard program that shares polar instructional materials and provides learning opportunities for K-12 educators. The PAL-LTER team is also leveraging the development of Out of School Time materials for afterschool and summer camp programs, sharing Palmer LTER-specific teaching materials with University, Museum, and 4-H Special Interest Club partners. Part 2: Technical description Polar ecosystems are among the most rapidly changing on Earth. The Palmer LTER (PAL-LTER) program builds on three decades of coordinated research along the western side of the Antarctic Peninsula (WAP) to gain new mechanistic and predictive understanding of ecosystem changes in response to disturbances spanning long-term decadal (‘press’) drivers and changes due to higher-frequency (‘pulse’) drivers, such as large storms and extreme seasonal anomaly in sea ice cover. The influence of major natural climate modes that modulate variations in sea ice, weather, and oceanographic conditions to drive changes in ecosystem structure and function (e.g., El Niño Southern Oscillation and Southern Annular Mode) are being studied at multiple time scales –from diel, seasonal, interannual, to decadal intervals, and space scales–from hemispheric to global scale investigated by remote sensing, the regional scales. Specifically, the team is evaluating how variability of physical properties (such as vertical and alongshore connectivity processes) interact to modulate biogeochemical cycling and community ecology in the WAP region. The study is providing an evaluation of ecosystem resilience and ecological responses to long-term “press-pulse” drivers and a decadal-level reversal in sea ice coverage. This program is providing fundamental understanding of population and biogeochemical responses for a marine ecosystem experiencing profound change. 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. | POLYGON((-79.65 -63.738,-77.9728 -63.738,-76.29560000000001 -63.738,-74.61840000000001 -63.738,-72.94120000000001 -63.738,-71.26400000000001 -63.738,-69.58680000000001 -63.738,-67.9096 -63.738,-66.2324 -63.738,-64.5552 -63.738,-62.878 -63.738,-62.878 -64.3683,-62.878 -64.9986,-62.878 -65.6289,-62.878 -66.25919999999999,-62.878 -66.8895,-62.878 -67.5198,-62.878 -68.1501,-62.878 -68.7804,-62.878 -69.41069999999999,-62.878 -70.041,-64.5552 -70.041,-66.2324 -70.041,-67.9096 -70.041,-69.5868 -70.041,-71.26400000000001 -70.041,-72.94120000000001 -70.041,-74.61840000000001 -70.041,-76.29560000000001 -70.041,-77.9728 -70.041,-79.65 -70.041,-79.65 -69.41069999999999,-79.65 -68.7804,-79.65 -68.1501,-79.65 -67.5198,-79.65 -66.8895,-79.65 -66.25919999999999,-79.65 -65.6289,-79.65 -64.9986,-79.65 -64.3683,-79.65 -63.738)) | POINT(-71.26400000000001 -66.8895) | false | false | |||||||
OPP-PRF Pygoscelis Penguin Response to Potential Prey Retention along the West Antarctic Peninsula
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2138277 |
2022-07-19 | Gallagher, Katherine | Pygoscelis penguins are central place foragers during the summer while they raise their chicks. They leave and return to the same colony location after hunting for food and rely on the availability of Antarctic krill, their primary food source. This research focuses on whether penguin diets and colony location reflect the retention of prey around and near colonies on the West Antarctic Peninsula. Eddies and other oceanographic processes may facilitate prey retention at certain locations, driving penguin colony establishment and success. This project hypothesizes that Pygoscelis penguin diets will be composed of more Antarctic krill (Euphausia superba) when local prey retention is high, possibly due to subsurface eddies. This hypothesis will be tested using satellite-based estimates of Pygoscelis penguin diet composition using multispectral sensor data to estimate nitrogen values and infer trophic level. Prey retention will be calculated along the peninsula using the Regional Ocean Modeling System (ROMS). Simulated particles and diel vertical migration will be used to mimic krill behavior. These particles can be experimentally seeded across multiple depths in multiple years to assess residence times in the system. Using penguin colony data from the Mapping Application for Penguin Populations and Projected Dynamics (MAPPPD), the PI will correlate diet and retention metrics to local penguin colony growth and persistence and build a predictive model of where colonies may form in the future. 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. | POLYGON((-78 -62,-76.2 -62,-74.4 -62,-72.6 -62,-70.8 -62,-69 -62,-67.2 -62,-65.4 -62,-63.6 -62,-61.8 -62,-60 -62,-60 -63,-60 -64,-60 -65,-60 -66,-60 -67,-60 -68,-60 -69,-60 -70,-60 -71,-60 -72,-61.8 -72,-63.6 -72,-65.4 -72,-67.2 -72,-69 -72,-70.8 -72,-72.6 -72,-74.4 -72,-76.2 -72,-78 -72,-78 -71,-78 -70,-78 -69,-78 -68,-78 -67,-78 -66,-78 -65,-78 -64,-78 -63,-78 -62)) | POINT(-69 -67) | false | false | ||||||||
Physiological Ecology of "Herbivorous" Antarctic Copepods
|
1746087 |
2021-08-06 | Tarrant, Ann | Animals in the polar oceans have adapted to dramatic seasonal changes in day length, food availability, and ice cover, as well as to consistently cold waters. This project focuses on the adaptations of copepods - small animals that live in the water column and are an important food source to many different predators. The field studies will take place in the western Antarctic Peninsula, an environment and ecosystem that is rapidly changing. Antarctic copepods have developed particular feeding and behavioral strategies to survive in their very seasonal environment, however it is not known how each of these species will respond to environmental change. The overall goal of this project is to examine and compare these adaptations across species and to understand how each species responds to short-term changes in food availability. The project contains three main objectives: the first objective is to compare the sets of genes across species, especially looking at genes related to storage of energy from food. The second objective is to measure and compare the responses of copepods to changes in food availability. The third objective is to determine how variation across the western Antarctic Pensinsula habitat affects the feeding condition of the copepods. To make the data more useful to the broader research community, a database will be developed enabling easy comparison of genetic information between copepod species. This project will provide hands-on training opportunities to graduate and undergraduate student and will seek to recruit students from underrepresented groups. Results and scientific concepts will be shared through outreach activities, including an expedition blog, a series of interactive animations, and public presentations. Polar marine organisms have adapted to dramatic seasonal changes in photoperiod, light intensity, and ice cover, as well as to cold but stable thermal environments. The western Antarctic Peninsula, the focal region for the field studies, has experienced rapid warming and ice melt. While it is difficult to predict exactly how physical conditions in this region will change, effects on species distributions have already been documented. Large Antarctic copepods in the families Calanidae and Rhincalanidae are dominant components of the mesozooplankton that use different metabolic and behavioral strategies to optimize their use of a highly seasonal food supply. The overall goal of this project is to leverage molecular approaches to examine the physiological and metabolic adaptations at the individual and species level. The project focuses on three main objectives: the first objective is to characterize the gene complement and stage-specific gene expression patterns in Antarctic copepods within an evolutionary context. The second objective is to measure and compare the physiological and molecular responses of juvenile copepods to variable feeding conditions. The third objective is to characterize metabolic variation within natural copepod populations. The metabolically diverse Antarctic copepods also provide an excellent opportunity to compare mechanisms regulating energy storage and utilization and to test hypotheses regarding the roles of specific genes. The field studies will aim to utilize information from an ongoing long term research program (the Palmer Long-Term Ecological Research), which complements the ongoing program and provides extensive context for this project. To make the data more useful to the research community, a database will be developed facilitating comparison of transcriptomes between copepod species. This project will provide hands-on training opportunities to graduate and undergraduate students. Efforts will be made to recruit students who are members of underrepresented minorities. Results and scientific concepts will be broadly disseminated through an expedition blog, a series of interactive animations, and public presentations. 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. | POLYGON((-80 -60,-77.5 -60,-75 -60,-72.5 -60,-70 -60,-67.5 -60,-65 -60,-62.5 -60,-60 -60,-57.5 -60,-55 -60,-55 -61,-55 -62,-55 -63,-55 -64,-55 -65,-55 -66,-55 -67,-55 -68,-55 -69,-55 -70,-57.5 -70,-60 -70,-62.5 -70,-65 -70,-67.5 -70,-70 -70,-72.5 -70,-75 -70,-77.5 -70,-80 -70,-80 -69,-80 -68,-80 -67,-80 -66,-80 -65,-80 -64,-80 -63,-80 -62,-80 -61,-80 -60)) | POINT(-67.5 -65) | false | false | ||||||||
Collaborative Research: Chemoautotrophy in Antarctic Bacterioplankton Communities Supported by the Oxidation of Urea-derived Nitrogen
|
1643466 1643345 |
2020-12-18 | Hollibaugh, James T.; Popp, Brian |
|
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. | 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)) | POINT(-71.1170125 -66.644054165) | false | false | |||||||
Production and Fate of Oxylipins in Waters of the Western Antarctic Peninsula: Linkages Between UV Radiation, Lipid Peroxidation, and Carbon Cycling
|
1543328 |
2020-06-19 | Van Mooy, Benjamin |
|
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. | None | None | false | false | |||||||
Organic carbon oxidation and iron remobilization by West Antarctic shelf sediments
|
1551195 |
2020-06-16 | Burdige, David; Christensen, John |
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General Statement: The continental shelf region west of the Antarctic Peninsula has recently undergone dramatic changes and ecosystem shifts, and the community of organisms that live in, or feed off, the sea floor sediments is being impacted by species invasions from the north. Previous studies of these sediments indicate that this community may consume much more of the regional productivity than previously estimated, suggesting that sediments are a rich and important component of this ecosystem and one that may be ripe for dramatic change. Furthermore, under richer sediment conditions, iron is mobilized and released back to the water column. Since productivity in this ecosystem is thought to be limited by the availability of iron, increased rates of iron release from these sediments could stimulate productivity and promote greater overall ecosystem change. In this research, a variety of sites across the shelf region will be sampled to accurately evaluate the role of sediments in consuming ecosystem productivity and to estimate the current level of iron release from the sediments. This project will provide a baseline set of sediment results that will present a more complete picture of the west Antarctic shelf ecosystem, will allow for comparison with water column measurements and for evaluation of the fundamental workings of this important ecosystem. This is particularly important since high latitude systems may be vulnerable to the effects of climate fluctuations. Both graduate and undergraduate students will be trained. Presentations will be made at scientific meetings, at other universities, and at outreach events. A project web site will present key results to the public and explain how this new information improves understanding of Antarctic ecosystems. Technical Description of Project: In order to determine the role of sediments within the west Antarctic shelf ecosystem, this project will determine the rates of sediment organic matter oxidation at a variety of sites across the Palmer Long Term Ecosystem Research (LTER) study region. To estimate the rates of release of iron and manganese from the sediments, these same sites will be sampled for detailed vertical distributions of the concentrations of these metals both in the porewaters and in important mineral phases. Since sediment sampling will be done at LTER sites, the sediment data can be correlated with the rich productivity data set from the LTER. In detail, the project: a) will determine the rates of oxygen consumption, organic carbon oxidation, nutrient release, and iron mobilization by shelf sediments west of the Antarctic Peninsula; b) will investigate the vertical distribution of diagenetic reactions within the sediments; and c) will assess the regional importance of these sediment rates. Sediment cores will be used to determine sediment-water fluxes of dissolved oxygen, total carbon dioxide, nutrients, and the vertical distributions of these dissolved compounds, as well as iron and manganese in the pore waters. Bulk sediment properties of porosity, organic carbon and nitrogen content, carbonate content, biogenic silica content, and multiple species of solid-phase iron, manganese, and sulfur species will also be determined. These measurements will allow determination of total organic carbon oxidation and denitrification rates, and the proportion of aerobic versus anaerobic respiration at each site. Sediment diagenetic modeling will link the processes of organic matter oxidation to metal mobilization. Pore water and solid phase iron and manganese distributions will be used to model iron diagenesis in these sediments and to estimate the iron flux from the sediments to the overlying waters. Finally, the overall regional average and distribution of the sediment processes will be compared with the distributions of seasonally averaged chlorophyll biomass and productivity. | POLYGON((-71 -64,-70.1 -64,-69.2 -64,-68.3 -64,-67.4 -64,-66.5 -64,-65.6 -64,-64.7 -64,-63.8 -64,-62.9 -64,-62 -64,-62 -64.4,-62 -64.8,-62 -65.2,-62 -65.6,-62 -66,-62 -66.4,-62 -66.8,-62 -67.2,-62 -67.6,-62 -68,-62.9 -68,-63.8 -68,-64.7 -68,-65.6 -68,-66.5 -68,-67.4 -68,-68.3 -68,-69.2 -68,-70.1 -68,-71 -68,-71 -67.6,-71 -67.2,-71 -66.8,-71 -66.4,-71 -66,-71 -65.6,-71 -65.2,-71 -64.8,-71 -64.4,-71 -64)) | POINT(-66.5 -66) | false | false |