The distribution of dimethyl sulphide and dimethylsulphoniopropionate in Antarctic waters and sea ice

Dimethyl sulphide (DMS) and particulate and dissolved fractions of dimethylsulphoniopropionate (DMSPp and DMSPd) were measured on two simultaneous cruises through the Drake Passage to the Bellingshausen Sea, Antarctica, during October to December 1992. Overall, average surface water concentrations for DMS and DMSPp were 2 nM (0.15–27 nM) and 25.6 nM (2–69 nM), respectively. Higher concentrations (DMS 5.8 and DMSPp 41.2 nM) were observed in a phytoplankton bloom forming a band between 67.2° and 68.2°S, associated with the Southern Polar Front. Concentrations of DMS + DMSP in ice were very high (up to 546 nM) but in the underlying water were 20 to 500 times lower. Comparison of sulphur data, pigments and phytoplankton species counts showed correlation of DMSPp with 19ʹ-hexanoyloxyfucoxanthin (Hex) and Phaeocystis sp. A seasonal cycle for DMS in Antarctic surface waters, based on all available literature data, is discussed in terms of the probable Antarctic Ocean contribution to the global ocean DMS flux.