The Southern Ocean "superbloom" of 2000: implications for carbon cycling

During the austral spring bloom in January-February, 2000 the concentration of surface chlorophyll-a (Chl) in the Southern Ocean was higher than the long-term average based on the 1997-2005 ocean color data. Chlorophyll anomalies were not uniformly distributed as areas with 3-4 times higher Chl were interspersed with areas of up to 3-4 times lower than the long-term mean. In general, Chl was nearly 50% higher in the Indian, Atlantic and Western Pacific sectors south of 60S but about normal in Western Pacific. All sectors south of 60S had also colder than normal sea-surface temperature (SST). Export flux of carbon calculated according to the model of Laws (2004) was almost double for the whole Southern Ocean during early 2000 compared to 1997. The interannual fluctuations in the rate of carbon removal from the euphotic zone should have implications for global carbon cycling and gas exchange. We investigate the relationships between these anomalies and various climatic indices (SOI, the Antarctic Circumpolar Wave), and the potential mechanisms causing the Chl anomalies.