The Role of DMSP and DMS in the Global Sulfur Cycle and Climate Regulation

Abstract

In 1972 Lovelock et al. published evidence of the ubiquity of DMS in surface seawater and proposed that marine DMS was the key compound transferring sulfur from the sea to the land via the atmosphere. At that time biochemical data were already available which suggested that DMSP could be the precursor of DMS in marine ecosystems. In the intervening years thousands of DMS and DMSP measurements have been made in coastal, shelf and open ocean waters and much more is now known about the water column processes which lead to DMS production. This paper will concentrate on the regional and global aspects of DMSP, which result from its role as the major precursor of DMS. DMS is now known to have 3 major environmental roles: it is the dominant volatile compound in the global sulfur cycle, the products of its atmospheric oxidation are acidic and therefore affect the acid-base balance of aerosols and rainwater, and aerosol particles derived from DMS are efficient cloud condensation nuclei (CCN) which have climatic significance. I will focus on the marine environment and discuss the sea-to-air exchange process, aspects of the atmospheric chemistry of DMS, the role of DMS in the sulfur cycle and its climatic significance.