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Biology & Medicine
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Dr. Polly Penhale
Program Manager
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B-047-M
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NSF/OPP Award 00-87401
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Station:
McMurdo Station
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RPSC POC:
Karl Newyear
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Research Site(s):
McMurdo Station, USCG Icebreaker
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Dates in Antarctica:
Mid December to mid February
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Interannual Variability in the Antarctic-Ross Sea (IVARS): Nutrients and seasonal production
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Photo not available.
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Deploying Team Members:
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Britt Anderson
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Vernon L. Asper
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Robert Carroll
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Liza DeLizo
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Jennifer Dreyer
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Paul Field
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Grace Henderson
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Tina Johnson
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David Malmquist
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Kevin Martin
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Jacques Oliver
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Leah Oliver
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Scott Michael Polk
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Gillian Potter
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Jeremy Potter
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Marta Sanderson
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Amy R. Shields
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Walker O. Smith
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Sasha Tozzi
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Research Objectives:
The oceanography of the Ross Sea is relatively well known, including the physical oceanography and hydrography, nutrient concentrations (nitrate and silicic acid), and phytoplankton biomass and species composition. However, marked variations in these variables occur spatially and temporally. Indeed, the variations with time are the greatest factor in the Ross Sea habitat. For example, throughout much of the winter the Ross Sea is ice covered, and no incident radiation is available to drive photosynthesis. In contrast, during the summer months the Ross Sea is ice-free, and large accumulations of phytoplankton biomass occur.
In addition to these seasonal changes, variations among years occur in all oceanographic variables, whether they be current velocities and directions, ice concentration, winds, or phytoplankton productivity. The causes and consequences of these interannual variations, however, are poorly known. They likely have both local and remote drivers; that is, ice concentrations are likely controlled by the antarctic circumpolar wave and by basin-wide changes induced by El Niño. Regardless of the causes, the degree of variation among years in biological variables is unknown, and this is what IVARS seeks to explore. Ultimately researchers hope to understand not only the causes, but also the consequences to the food web of the region.
This project's objectives are to quantify the variations in seasonal community production in the southern Ross Sea and to assess the variations among years. This is done by two means: a) collecting nutrient profiles at a set grid/number of stations during two cruises, and b) deploying moorings with a variety of chemical and biological sensors that define the temporal pattern of nutrient uptake (and its oceanographic controls) at two locations. Together, an understanding of the spatial and temporal variations of community production can be obtained, and thus an idea of the interannual variations of the entire region. Ultimately researchers will link these with both large-scale processes of the Pacific Basin and food web effects.
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