USAP-DC

{"dp_type": "Dataset", "free_text": "Sulfur"}

[{"awards": null, "bounds_geometry": null, "date_created": "Thu, 05 Sep 2024 00:00:00 GMT", "description": "The effects of soluble impurities on the flow of glaciers and ice sheets as well as the effects of ice flow on impurities migration are not well understood. This study investigates the effects of sulfuric acid (H2SO4) concentrations ranging from 10 to 25 ppm on the flow and fabric of polycrystalline ice under compression at temperatures of -3\u00b0C and -12\u00b0C. The results show that H2SO4-doped polycrystalline ice deforms significantly faster than high-purity polycrystalline ice, with the deformation rate being 1.5 to 3 times higher. At -12\u00b0C, the presence of H2SO4 within the grains induces the most ice softening, whereas at -3\u00b0C, H2SO4\u0027s softening effects are observed both within the grains and at grain boundaries. The migration of H2SO4 to grain boundaries during deformation leads to the formation of a liquid-like layer, with increased solubility at higher temperatures potentially homogenizing the impurities within the ice matrix. This homogenization at -3\u00b0C suggests that post-depositional processes near the bed of ice sheets could significantly alter sulfate records. At -12\u00b0C, where homogenization is absent, impurity-induced dislocation processes may heavily influence deformation and impurity migration. Additionally, the comparison of natural ice with lab-grown samples indicates that fabric development significantly impacts compressive strength and creep rates, with implications for the understanding of impurity-induced deformation processes in polar ice.", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere", "locations": "Antarctica", "north": null, "nsf_funding_programs": null, "persons": "Ogunmolasuyi, Ayobami", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": null, "title": "The Impacts of the Microstructural Location of H2SO4 on the Flow of Polycrystalline Ice", "uid": "601831", "west": null}, {"awards": "1851022 Fudge, Tyler", "bounds_geometry": ["POINT(123.33 -75.09)"], "date_created": "Fri, 22 Dec 2023 00:00:00 GMT", "description": "Volcanic deposition of sulfuric acid in ice cores is important both for understanding past volcanic activity and for synchronizing ice core timescales. Sulfuric acid has a low eutectic point, so it can potentially exist in liquid at grain boundaries and veins, accelerating chemical diffusion. A high effective diffusivity would allow post-depositional diffusion to obscure the climate history and the peak matching among older portions of ice cores. Here, we use records of sulfate from the EPICA Dome C (EDC) ice core to estimate the effective diffusivity of sulfuric acid in ice. We focus on EDC because multiple glacial-interglacial cycles are preserved, allowing analysis for long timescales and deposition in similar climates. We calculate the mean concentration gradient and the width of prominent volcanic events, and analyze the evolution of each with depth/age. We find the effective diffusivities for interglacials and glacial maximums to be 5 \u00b1 3 \u00d7 10-9 m2 a-1, an order of magnitude lower than a previous estimate derived from the Holocene portion of EDC (Barnes et al., 2003). The effective diffusivity may be even smaller if the bias from artificial smoothing from the sampling is accounted for. Effective diffusivity is not obviously affected by the ice temperature until about -10\u00b0C, 3000m depth, which is also where anomalous sulfate peaks begin to be observed (Traversi et al., 2009). Low effective diffusivity suggests that sulfuric acid is not readily diffusing in liquid-like veins in the upper portions of the Antarctic ice sheet and that records may be preserved in deep, old ice if the ice temperature remains well below the pressure melting point.", "east": 123.33, "geometry": ["POINT(123.33 -75.09)"], "keywords": "Antarctica", "locations": "Antarctica", "north": -75.09, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Fudge, T. J.; Severi, Mirko", "project_titles": "Collaborative Research: The Impact of Impurities and Stress State on Polycrystalline Ice Deformation", "projects": [{"proj_uid": "p0010211", "repository": "USAP-DC", "title": "Collaborative Research: The Impact of Impurities and Stress State on Polycrystalline Ice Deformation"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -75.09, "title": "EPICA Dome C Sulfate Data 7-3190m", "uid": "601759", "west": 123.33}, {"awards": "1543537 Priscu, John", "bounds_geometry": ["POINT(-149.50134 -84.640287)"], "date_created": "Wed, 01 Feb 2023 00:00:00 GMT", "description": "This dataset contains bulk sediment properties measurements from cores collected from Mercer Subglacial Lake by the SALSA project. Included are: physical properties (bulk density, mass water content, porosity, shear strength, particle size distribution, and mineralogy); carbon (inorganic and organic); iron (ascorbate- and dithionite-extractable); and sulfur (acid-volatile and chromium-reducible).", "east": -149.50134, "geometry": ["POINT(-149.50134 -84.640287)"], "keywords": "Antarctica; Carbon; Glacier; Glaciers/ice Sheet; Glaciers/Ice Sheet; Iron; Mercer Subglacial Lake; Mineralogy; Particle Size; Physical Properties; SALSA; Sediment Core; Sulfur; West Antarctic Ice Sheet", "locations": "West Antarctic Ice Sheet; Mercer Subglacial Lake; Antarctica; Mercer Subglacial Lake", "north": -84.640287, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Dore, John; Campbell, Timothy; Michaud, Alexander; Hawkings, Jon; Skidmore, Mark; Tranter, Martyn; Venturelli, Ryan A; Science Team, SALSA", "project_titles": "Collaborative Research: Subglacial Antarctic Lakes Scientific Access (SALSA): Integrated Study of Carbon Cycling in Hydrologically-active Subglacial Environments", "projects": [{"proj_uid": "p0010119", "repository": "USAP-DC", "title": "Collaborative Research: Subglacial Antarctic Lakes Scientific Access (SALSA): Integrated Study of Carbon Cycling in Hydrologically-active Subglacial Environments"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -84.640287, "title": "Discrete bulk sediment properties data from Mercer Subglacial Lake", "uid": "601661", "west": -149.50134}, {"awards": "1543450 Countway, Peter", "bounds_geometry": ["POLYGON((-66 -63,-65.7 -63,-65.4 -63,-65.1 -63,-64.8 -63,-64.5 -63,-64.2 -63,-63.9 -63,-63.6 -63,-63.3 -63,-63 -63,-63 -63.3,-63 -63.6,-63 -63.9,-63 -64.2,-63 -64.5,-63 -64.8,-63 -65.1,-63 -65.4,-63 -65.7,-63 -66,-63.3 -66,-63.6 -66,-63.9 -66,-64.2 -66,-64.5 -66,-64.8 -66,-65.1 -66,-65.4 -66,-65.7 -66,-66 -66,-66 -65.7,-66 -65.4,-66 -65.1,-66 -64.8,-66 -64.5,-66 -64.2,-66 -63.9,-66 -63.6,-66 -63.3,-66 -63))"], "date_created": "Tue, 03 Jan 2023 00:00:00 GMT", "description": "Biogenic sulfur samples were collected from Station E (Palmer Station, Antarctica) and from associated incubation experiments with Station E water. Samples were analyzed for Dimethyl Sulfide (DMS), particulate Dimethylsulfoniopropionate (DMSPp), dissolved Dimethylsulfoniopropionate (DMSPd), particulate Dimethylsulfoxide (DMSOp), dissolved Dimethylsulfoxide (DMSOd) and DMSP lyase activity. All analyses were performed at Palmer Station during scientific deployments. An overview of the methods used for these analyses is included in a secondary tab with the uploaded data.", "east": -63.0, "geometry": ["POINT(-64.5 -64.5)"], "keywords": "Antarctica; Biota; Dimethyl Sulfide; Dimethylsulfoniopropionate; Dimethylsulfoxide; DMSP; DMSP Lyase; Palmer Station", "locations": "Antarctica; Palmer Station", "north": -63.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Countway, Peter; Matrai, Patricia", "project_titles": "Microbial Community Structure and Expression of Functional Genes Involved in the Seasonal Cycling of DMSP in the Southern Ocean", "projects": [{"proj_uid": "p0010120", "repository": "USAP-DC", "title": "Microbial Community Structure and Expression of Functional Genes Involved in the Seasonal Cycling of DMSP in the Southern Ocean"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -66.0, "title": "Biogenic Sulfur Samples from Station E (Palmer Station, Antarctica) and Associated Incubation Experiments", "uid": "601648", "west": -66.0}, {"awards": "0944659 Kiene, Ronald", "bounds_geometry": ["POLYGON((-160 -68,-159 -68,-158 -68,-157 -68,-156 -68,-155 -68,-154 -68,-153 -68,-152 -68,-151 -68,-150 -68,-150 -69,-150 -70,-150 -71,-150 -72,-150 -73,-150 -74,-150 -75,-150 -76,-150 -77,-150 -78,-151 -78,-152 -78,-153 -78,-154 -78,-155 -78,-156 -78,-157 -78,-158 -78,-159 -78,-160 -78,-160 -77,-160 -76,-160 -75,-160 -74,-160 -73,-160 -72,-160 -71,-160 -70,-160 -69,-160 -68))"], "date_created": "Thu, 01 Jan 2015 00:00:00 GMT", "description": "Spectacular blooms of Phaeocystis antarctica in the Ross Sea, Antarctica are the source of some of the world\u0027s highest concentrations of dimethylsulfoniopropionate (DMSP) and its volatile degradation product, dimethylsulfide (DMS). The flux of DMS from the oceans to the atmosphere in this region and its subsequent gas phase oxidation generates aerosols that have a strong influence on cloud properties and possibly climate. In the oceans, DMS and DMSP are quantitatively significant components of the carbon, sulfur, and energy flows in marine food webs, especially in the Ross Sea. Despite its central role in carbon and sulfur biogeochemistry in the Ross Sea, surprisingly little is known about the physiological functions of DMSP in P. Antarctica. The research will isolate and characterize DMSP lyases from P. antarctica, with the goal of obtaining amino acid and gene sequence information on these important enzymes. The physiological studies will focus on the effects of varying intensities of photosynthetically active radiation, with and without ultraviolet radiation as these are factors that we have found to be important controls on DMSP and DMS dynamics. The research also will examine the effects of prolonged darkness on the dynamics of DMSP and related compounds in P. antarctica, as survival of this species during the dark Antarctic winter and at sub-euphotic depths appears to be an important part of the Phaeocystis? ecology. A unique aspect of this work is the focus on measurements of intracellular MSA, which if detected, would provide strong evidence for in vivo radical scavenging functions for methyl sulfur compounds. The study will advance understanding of what controls DMSP cycling and ultimately DMS emissions from the Ross Sea and also provide information on what makes P. antarctica so successful in this extreme environment. The research will directly benefit and build on several interrelated ocean-atmosphere programs including the International Surface Ocean Lower Atmosphere Study (SOLAS) program. The PIs will participate in several activities involving K-12 education, High School teacher training, public education and podcasting through the auspices of the Dauphin Island Sea Lab Discovery Hall program and SUNY ESF. Two graduate students will be employed full time, and six undergraduates (2 each summer) will be trained as part of this project.\n", "east": -150.0, "geometry": ["POINT(-155 -73)"], "keywords": "Antarctica; Biota; Chemistry:fluid; Chemistry:Fluid; Geochemistry; Oceans; Ross Sea", "locations": "Ross Sea; Antarctica", "north": -68.0, "nsf_funding_programs": null, "persons": "Kiene, Ronald", "project_titles": "Collaborative Research: Ecophysiology of DMSP and related compounds and their contributions to carbon and sulfur dynamics in Phaeocystis antarctica", "projects": [{"proj_uid": "p0000085", "repository": "USAP-DC", "title": "Collaborative Research: Ecophysiology of DMSP and related compounds and their contributions to carbon and sulfur dynamics in Phaeocystis antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Ecophysiology of DMSP and related compounds and their contributions to carbon and sulfur dynamics in Phaeocystis antarctica", "uid": "600150", "west": -160.0}, {"awards": "0944686 Kieber, David", "bounds_geometry": ["POLYGON((-160 -68,-159 -68,-158 -68,-157 -68,-156 -68,-155 -68,-154 -68,-153 -68,-152 -68,-151 -68,-150 -68,-150 -69,-150 -70,-150 -71,-150 -72,-150 -73,-150 -74,-150 -75,-150 -76,-150 -77,-150 -78,-151 -78,-152 -78,-153 -78,-154 -78,-155 -78,-156 -78,-157 -78,-158 -78,-159 -78,-160 -78,-160 -77,-160 -76,-160 -75,-160 -74,-160 -73,-160 -72,-160 -71,-160 -70,-160 -69,-160 -68))"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "Spectacular blooms of Phaeocystis antarctica in the Ross Sea, Antarctica are the source of some of the world\u0027s highest concentrations of dimethylsulfoniopropionate (DMSP) and its volatile degradation product, dimethylsulfide (DMS). The flux of DMS from the oceans to the atmosphere in this region and its subsequent gas phase oxidation generates aerosols that have a strong influence on cloud properties and possibly climate. In the oceans, DMS and DMSP are quantitatively significant components of the carbon, sulfur, and energy flows in marine food webs, especially in the Ross Sea. Despite its central role in carbon and sulfur biogeochemistry in the Ross Sea, surprisingly little is known about the physiological functions of DMSP in P. antarctica. The research will isolate and characterize DMSP lyases from P. antarctica, with the goal of obtaining amino acid and gene sequence information on these important enzymes. The physiological studies will focus on the effects of varying intensities of photosynthetically active radiation, with and without ultraviolet radiation as these are factors that we have found to be important controls on DMSP and DMS dynamics. The research also will examine the effects of prolonged darkness on the dynamics of DMSP and related compounds in P. antarctica, as survival of this species during the dark Antarctic winter and at sub-euphotic depths appears to be an important part of the Phaeocystis\u0027 ecology. A unique aspect of this work is the focus on measurements of intracellular MSA, which if detected, would provide strong evidence for in vivo radical scavenging functions for methyl sulfur compounds. The study will advance understanding of what controls DMSP cycling and ultimately DMS emissions from the Ross Sea and also provide information on what makes P. antarctica so successful in this extreme environment. The research will directly benefit and build on several interrelated ocean-atmosphere programs including the International Surface Ocean Lower Atmosphere Study (SOLAS) program. The PIs will participate in several activities involving K-12 education, High School teacher training, public education and podcasting through the auspices of the Dauphin Island Sea Lab Discovery Hall program and SUNY ESF. Two graduate students will be employed full time, and six undergraduates (2 each summer) will be trained as part of this project.\n", "east": -150.0, "geometry": ["POINT(-155 -73)"], "keywords": "Biota; Ross Sea; Southern Ocean", "locations": "Ross Sea; Southern Ocean", "north": -68.0, "nsf_funding_programs": null, "persons": "Kieber, David John", "project_titles": "Collaborative Research: Ecophysiology of DMSP and related compounds and their contributions to carbon and sulfur dynamics in Phaeocystis antarctica", "projects": [{"proj_uid": "p0000085", "repository": "USAP-DC", "title": "Collaborative Research: Ecophysiology of DMSP and related compounds and their contributions to carbon and sulfur dynamics in Phaeocystis antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Ecophysiology of DMSP and related compounds and their contributions to carbon and sulfur dynamics in Phaeocystis antarctica", "uid": "600117", "west": -160.0}, {"awards": "0337933 Cole-Dai, Jihong", "bounds_geometry": ["POINT(0 -90)"], "date_created": "Tue, 19 Nov 2013 00:00:00 GMT", "description": "A 180 m ice core drilled at South Pole in 2004/2005 was analyzed for concentrations of major ions at a depth resolution of approximately 2 cm. Measured ions are chloride, nitrate, sulfate, sodium, potassium, magnesium and calcium. The bottom of the core has been dated to 1830 years before 2004.", "east": 0.0, "geometry": ["POINT(0 -90)"], "keywords": "Antarctica; Chemistry:ice; Chemistry:Ice; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Ion Chromatograph; South Pole", "locations": "South Pole; Antarctica", "north": -90.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Cole-Dai, Jihong", "project_titles": "Collaborative Research: Investigating Atmospheric Chemistry and Dynamics through Oxygen and Sulfur Isotopes in Volcanic Sulfate from South Pole Ice Cores", "projects": [{"proj_uid": "p0000031", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Atmospheric Chemistry and Dynamics through Oxygen and Sulfur Isotopes in Volcanic Sulfate from South Pole Ice Cores"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Major Ion Concentrations in 2004 South Pole Ice Core", "uid": "609542", "west": 0.0}, {"awards": "0538520 Thiemens, Mark", "bounds_geometry": ["POINT(-114.216667 -78.916667)"], "date_created": "Mon, 01 Nov 2010 00:00:00 GMT", "description": "This data set contains measurements of multiple sulfur and oxygen isotopes from sulfates, from an ice core drilled at the West Antarctic Ice Sheet (WAIS) Divide site in 2005. The initial sulfate measurements, analyzed in 2008 from the 70 meter WAIS 2005A core, are 12 meter averages and span the pre-industrial to industrial transition, from the late 1700s to 2005. This data set is part of the West Antarctic Ice Sheet Divide Ice Core (WAISCORES) project.\n\nData are available via FTP in Microsoft Excel (.xlsx) format.", "east": -114.216667, "geometry": ["POINT(-114.216667 -78.916667)"], "keywords": "Antarctica; Chemistry:ice; Chemistry:Ice; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Ice Core Records; Paleoclimate; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -78.916667, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Thiemens, Mark H.", "project_titles": "Collaborative Research: Multiple-isotope Analysis of Nitrate and Sulfate in the West Antarctic Ice Sheet Divide Ice Core", "projects": [{"proj_uid": "p0000020", "repository": "USAP-DC", "title": "Collaborative Research: Multiple-isotope Analysis of Nitrate and Sulfate in the West Antarctic Ice Sheet Divide Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.916667, "title": "Multiple Isotope Analysis of Sulfate in the West Antarctic Ice Sheet Divide Ice Core", "uid": "609479", "west": -114.216667}, {"awards": "0338097 DiTullio, Giacomo", "bounds_geometry": ["POLYGON((-169.94 -52.24,-169.449 -52.24,-168.958 -52.24,-168.467 -52.24,-167.976 -52.24,-167.485 -52.24,-166.994 -52.24,-166.503 -52.24,-166.012 -52.24,-165.521 -52.24,-165.03 -52.24,-165.03 -54.879,-165.03 -57.518,-165.03 -60.157,-165.03 -62.796,-165.03 -65.435,-165.03 -68.074,-165.03 -70.713,-165.03 -73.352,-165.03 -75.991,-165.03 -78.63,-165.521 -78.63,-166.012 -78.63,-166.503 -78.63,-166.994 -78.63,-167.485 -78.63,-167.976 -78.63,-168.467 -78.63,-168.958 -78.63,-169.449 -78.63,-169.94 -78.63,-169.94 -75.991,-169.94 -73.352,-169.94 -70.713,-169.94 -68.074,-169.94 -65.435,-169.94 -62.796,-169.94 -60.157,-169.94 -57.518,-169.94 -54.879,-169.94 -52.24))"], "date_created": "Fri, 01 Jan 2010 00:00:00 GMT", "description": "The objectives of this proposal are to investigate the controls on the large-scale distribution and production of the two major bloom-forming phytoplankton taxa in the Southern Ocean, diatoms and Phaeocystis Antarctica. These two groups, through their involvement in the biogeochemical cycles of carbon, sulfur and nutrient elements, may have played important roles in the climate variations of the late Quaternary, and they also may be key players in future environmental change. A current paradigm is that irradiance and iron availability drive phytoplankton dynamics in the Southern Ocean. Recent work, however, suggests that carbon dioxide (CO2) concentrations may also be important in structuring algal assemblages, due to species-specific differences in the physiology. This proposal examines the interactive effects of iron, light and CO2 on the physiology, ecology and relative dominance of Phaeocystis and diatoms in the Southern Ocean. The Ross Sea is an ideal system in which to investigate the environmental factors that regulate the distribution and production of these two algal groups, since it is characterized by seasonal blooms of both P. Antarctica and diatoms that are typically separated in both space and time. This study will take the form of an interdisciplinary investigation that includes a field survey and statistical analysis of algal assemblage composition, iron, mixed layer depth, and CO2 levels in the southern Ross Sea, coupled with shipboard experiments to examine the response of diatom and P. Antarctica assemblages to high and low levels of iron, light and CO2 during spring and summer. This project will provide information on some of the major factors controlling the production and distribution of the two major bloom forming phytoplankton in the Southern Ocean and the related biogeochemical cycling of carbon, sulfur and nutrient elements. The results may ultimately advance the ability to predict how the Southern Ocean will be affected by and possibly modulate future climate change. This project will also make significant educational contributions at several levels, including the planned research involvement of graduate and undergraduate students, postdoctoral associates, a student teacher, and community outreach and educational activities. A number of activities are planned to interface the project with K-12 education. Presentations will be made at local schools to discuss the research and events of the research cruise. During the cruise there will be daily interactive email contact with elementary classrooms. Established websites will be used to allow students to learn about the ongoing research, and to allow researchers to communicate with students through text and downloaded images.", "east": -165.03, "geometry": ["POINT(-167.485 -65.435)"], "keywords": "Biota; Chemistry:fluid; Chemistry:Fluid; Diatom; Oceans; Phytoplankton; Ross Sea; Southern Ocean", "locations": "Ross Sea; Southern Ocean", "north": -52.24, "nsf_funding_programs": null, "persons": "DiTullio, Giacomo", "project_titles": "Collaborative Research: Interactive Effects of Iron, Light and Carbon Dioxide on Phytoplankton Community Dynamics in the Ross Sea", "projects": [{"proj_uid": "p0000540", "repository": "USAP-DC", "title": "Collaborative Research: Interactive Effects of Iron, Light and Carbon Dioxide on Phytoplankton Community Dynamics in the Ross Sea"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.63, "title": "Interactive Effects of Iron, Light and Carbon Dioxide on Phytoplankton Community Dynamics in the Ross Sea", "uid": "600036", "west": -169.94}, {"awards": "0440478 Tang, Kam", "bounds_geometry": ["POINT(166.66267 -77.85067)"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "Phaeocystis Antarctica is a widely distributed phytoplankton that forms dense blooms and aggregates in the Southern Ocean. This phytoplankton and plays important roles in polar ecology and biogeochemistry, in part because it is a dominant primary producer, a main component of organic matter vertical fluxes, and the principal producer of volatile organic sulfur in the region. Yet P. Antarctica is also one of the lesser known species in terms of its physiology, life history and trophic relationships with other organisms; furthermore, information collected on other Phaeocystis species and from different locations may not be applicable to P. Antarctica in the Ross Sea. P. Antarctica occurs mainly as two morphotypes: solitary cells and mucilaginous colonies, which differ significantly in size, architecture and chemical composition. Relative dominance between solitary cells and colonies determines not only the size spectrum of the population, but also its carbon dynamics, nutrient uptake and utilization. Conventional thinking of the planktonic trophic processes is also challenged by the fact that colony formation could effectively alter the predator-prey interactions and interspecific competition. However, the factors that regulate the differences between solitary and colonial forms of P. Antarctica are not well-understood. \n\nThe research objective of this proposal is therefore to address these over-arching questions: \n1. Do P. Antarctica solitary cells and colonies differ in growth, composition and photosynthetic rates? 2. How do nutrients and grazers affect colony development and size distribution of P. Antarctica? \n3. How do nutrients and grazers act synergistically to affect the long-term population dynamics of P. Antarctica? \n\nExperiments will be conducted in the McMurdo station with natural P. Antarctica assemblages and co-occurring grazers. Laboratory experiments will be conducted to study size-specific growth and photosynthetic rates of P. Antarctica, size-specific grazing mortality due to microzooplankton and mesozooplankton, the effects of macronutrients on the (nitrogen compounds) relative dominance of solitary cells and colonies, and the effects of micronutrient (Fe) and grazing related chemical signals on P. Antarctica colony development. Because this species is of critical importance in the Southern Ocean, and because this research will provide critical information on factors that regulate the role of P.Antarctica in food webs and biogeochemical cycles, a major gap in knowledge will be addressed. This project will train two marine science Ph.D. students. The investigators will also collaborate with the School of Education and a marine science museum to communicate polar science to a broader audience.", "east": 166.66267, "geometry": ["POINT(166.66267 -77.85067)"], "keywords": "Biota; McMurdo Sound; Oceans; Phytoplankton; Ross Sea; Southern Ocean; Zooplankton", "locations": "Southern Ocean; McMurdo Sound; Ross Sea", "north": -77.85067, "nsf_funding_programs": null, "persons": "Smith, Walker; Tang, Kam", "project_titles": "Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial forms of Phaeocystis antarctica", "projects": [{"proj_uid": "p0000214", "repository": "USAP-DC", "title": "Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial forms of Phaeocystis antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.85067, "title": "Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial Forms of Phaeocystis Antarctica", "uid": "600043", "west": 166.66267}, {"awards": "9615333 Saltzman, Eric", "bounds_geometry": ["POINT(-148.8 -81.7)"], "date_created": "Tue, 09 Mar 2004 00:00:00 GMT", "description": "This data set is a continuous, high-resolution record of biogenic sulfur (methanesulfonate, known as MSA and CH3SO3-) in the 1000 m deep Siple Dome A (SDMA) core, covering 100,000 to 20 years BP. The analysis was done on between August 2002 and November 2003 at the University of California, Irvine. Investigators used a mass spectrometer to measure methanesulfonate. Measurements are given as MSA concentration at various depths. Estimated age of the ice at each depth is also given.\n\nThis project was a part of the West Antarctic Ice Sheet Cores (WAISCORES) project for deep ice coring in West Antarctica. WAISCORES is supported by the Office of Polar Programs, National Science Foundation (NSF).", "east": -148.8, "geometry": ["POINT(-148.8 -81.7)"], "keywords": "Antarctica; Biota; Chemistry:ice; Chemistry:Ice; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Paleoclimate; Siple Dome; Siple Dome Ice Core; WAISCORES", "locations": "Siple Dome; Antarctica", "north": -81.7, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Saltzman, Eric; Dioumaeva, Irina; Finley, Brandon", "project_titles": "Biogenic Sulfur in the Siple Dome Ice Core", "projects": [{"proj_uid": "p0000251", "repository": "USAP-DC", "title": "Biogenic Sulfur in the Siple Dome Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": -81.7, "title": "Biogenic Sulfur in the Siple Dome Ice Core", "uid": "609201", "west": -148.8}]

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