Physical-biological interactions in the Southern Ocean

Abstract

Physical-biological interactions in the Southern Ocean were investigated using remote sensing data from several different satellite sensors. Satellite sea surface temperature data were used to study the dynamics of the Antarctic Polar Front (PF). Satellite ocean color data were used to estimate surface chlorophyll concentrations and their relation to various physical forcings within the Southern Ocean. A detailed study of phytoplankton blooms at the Antarctic Polar Front revealed that elevated chlorophyll concentrations (phytoplankton blooms) occur most often in areas where the PF interacts with large topographic features within the Southern Ocean. The physical dynamics of the PF are strongly influenced by the topography, and in turn strongly influence phytoplankton bloom dynamics. The analysis of satellite data from the modern Southern Ocean indicates that phytoplankton are limited by the availability of the micronutrient iron in most areas. This iron-limitation implies that the elevated iron inputs during glacial periods would have led to increased phytoplankton primary and export production and a stronger sink for atmospheric CO₂ in the Southern Ocean.