The SWEDARP 1997/98 marine expedition: overview

The SWEDARP 1997/98 expedition aboard the S.A. Agulhas focused on three study areas along the 6°E meridian: 60°S, the location of the spring ice edge; 56°S, the location of the winter ice edge; and 50.5°S, the Antarctic Polar Front. This intensive study was preceded by a north–south transect through the area measuring surface water properties while under way. An extensive measurement programme included hydrography, tracers, nutrients, organic carbon, trace metals, bacteria, and primary and secondary producers (including production and grazing rates). Analysis of the results from the three study areas does not identify a single factor limiting primary production: water column stability and the optical regime, and probably iron supply contributed to the control of primary production. The study area acted as a sink for atmospheric CO2 at the time of measurement, while analysis of water column carbon inventories indicated a net CO2 source integrated over the spring season.