HR: 11:20h
AN: OS22B-05 INVITED     [Abstracts]
TI: Multi-Satellite Characterization of Interannual Variation in Primary Production and Air-Sea CO₂ Flux in the Ross Sea, Antarctica
AU: * Arrigo, K R
EM: arrigo@stanford.edu
AF: Stanford University, Department of Geophysics, Stanford, CA 94305-2215 United States
AB: The Ross Sea is the most productive sector of the Southern Ocean, the largest of the three iron limited HNLC regions. This productivity supports a rich upper trophic level community, including large numbers of penguins, seals, and whales. It also represents a large sink for atmospheric CO₂. Since the advent of ocean color remote sensing using satellites such as CZCS, SeaWiFS, and MODIS, it has become increasingly clear that productivity in the Ross Sea is also characterized by a great deal of interannual variability. Passive microwave data from the Special Sensor Microwave/Imager show that distributions of sea ice within the Ross Sea vary markedly from year to year, with some years experiencing nearly ice-free springtime conditions while others remain nearly ice covered. This extreme variability in sea ice cover is due to changes in climate state as well as some unusual events specific to the Ross Sea, such as the calving of two enormous icebergs, one in 2000 and the other in 2002. Variation in ice cover during austral spring and summer impacts the growth of the phytoplankton community, whose cumulative rate of annual primary production ranges widely, from <10 Tg C in 2002-03 to almost 40 Tg C in 1999-00. When these satellite data are used in conjunction with a three-dimensional ocean ecosystem model of the Ross Sea, the calculated air-sea fluxes of CO₂ are even more variable, varying over 50-fold between 1997 and 2004. Not surprisingly, the lowest atmospheric flux of CO₂ into the surface waters of the Ross Sea (0.10 Tg C) is associated with the year having the lowest primary production and highest sea ice cover. The extreme sensitivity of rates of primary production and particularly air-sea CO₂ fluxes to changes in sea ice distribution in the Southern Ocean suggest that this region may undergo dramatic changes if global temperatures continue to rise, as they have in the vicinity of the Antarctic Peninsula.
DE: 4255 Numerical modeling (0545, 0560)
DE: 4275 Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934)
DE: 4806 Carbon cycling (0428)
DE: 4855 Phytoplankton
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005