Processes driving seasonal variability in DMS, DMSP, and DMSO concentrations and turnover in coastal Antarctic waters

Using several novel analytical and experimental techniques, we document variability in DMS, DMSP, and DMSO (DMS/P/O) concentrations and quantify dominant production and removal terms in the mixed layer DMS budget.

Our results demonstrate considerable seasonal variability in the concentration of DMS (range 0-20 nM), total DMSP (8-160 nM), and total DMSO (4-160 nM). Over the seasonal cycle, dissolved DMSP concentrations were well correlated with total DMSP concentrations and the abundance of Phaeocystis antarctica, while DMSO concentrations (total and dissolved) were well correlated with DMS concentrations. DMSP cleavage from the dissolved pool (mean rate=5.5 nM d(-1)) and release from microzooplankton grazing (mean 5.6 nM d(-1)) were the dominant sources of DMS, with smaller DMS production rates associated with DMSO reduction from the dissolved pool (mean 2.6 nM d(-1)) and krill grazing (mean 0.82 nM d(-1)).