During the ANT XXI/4 cruise with R/V Polarstern different locations on two N-S transects across the Antarctic Circumpolar Current (ACC) were investigated. Special emphasis was given on locations sampled by the European Iron Fertilization Experiment (EIFEX) during the preceding cruise. At the sediment-water interface of this site, steep oxygen gradients measured by means of an in situ microprofiler reflect a recent sedimentation of highly reactive organic material. This sedimentation event is suggested to be directly related to a previous plankton bloom and consecutive particle export that was observed in the water column by the EIFEX Group. Accordingly, cells of diatoms, auto- and heterotroph dinoflagellates, containing intact nuclei and chlorophyll-a could be identified by fluorescence microscopy in the fluff layer at the top of retrieved sediment cores from this area. High bacterial activities confirm the extraordinary high fluxes also found at other locations of the Polar Front area. Observed fluxes compare well to the spatial pattern of high chlorophyll concentrations obtained from SEAWIFS satellite observations at the Polar Front, confirming the potential of high particle / carbon export of this region in the Southern Ocean.
AWI Organizations > Geosciences > Marine Geochemistry
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL2-Southern Ocean climate and ecosystem