PRIMARY PRODUCTION IN SOUTHERN-OCEAN WATERS

The Southern Ocean forms a link between major ocean basins, is the sit e of deep and intermediate water ventilation, and is one of the few ar eas where macronutrients are underutilized by phytoplankton. Paradoxic ally, prior estimates of annual primary production are insufficient to support the Antarctic food web. Here we present results from a primar y production algorithm based upon monthly climatological phytoplankton pigment concentrations from the coastal zone color scanner (CZCS), Ph ytoplankton production was forced using monthly temperature profiles a nd a radiative transfer model that computed changes in photosynthetica lly usable radiation at each CZCS pixel location. Average daily produc tivity (g C m(-2) d(-1)) and total monthly production (Tg C month(-1)) were calculated for each of five geographic sectors (defined by longi tude) and three ecological provinces (defined by sea ice coverage and bathymetry as the pelagic province, the marginal ice zone, and the she lf). Annual primary production in the Southern Ocean (south of 50 degr ees S) was calculated to be 4414 Tg C yr(-1), 4-5 times higher than pr evious estimates made from in situ data. Primary production was greate st in the month of December (816 Tg C month(-1)) and in the pelagic pr ovince (contributing 88.6% of the annual primary production). Because of their small size the marginal ice zone (MIZ) and the shelf contribu ted only 9.5% and 1.8%, respectively, despite exhibiting higher daily production rates. The Ross Sea was the most productive region, account ing for 28% of annual production. The fourfold increase in the estimat e of primary production for the Southern Ocean likely makes the notion of an ''Antarctic paradox'' (primary production insufficient to suppo rt the populations of Southern Ocean grazers, including krill, copepod s, microzooplankton, etc.) obsolete.