Dimethyl sulphide and Phaeocystis: A review

Dimethyl sulphide (DMS) is the dominant sulphur gas found in surface marine waters and there is compelling evidence that it is formed biologically in these environments. In all areas so far investigated the oceans are found to be highly supersaturated (typically by two orders of magnitude) with respect to atmospheric levels of DMS, which indicates a net flux of the gas out of the oceans. In this paper, we first briefly review the environmental importance of the gas and particularly the role of its sea-to-air flux on atmospheric chemistry and physics. Then we discuss what is known of its mode of formation and cycling in seawater, before looking more specifically at the role and significance of Phaeocystis as a producer of DMS.