Title : Phytoplankton, Dimethyl sulfide and Aerosols in the Polar Atmosphere
Abstract : Marine phytoplankton can produce gaseous dimethyl sulfide (DMS), which is the most abundant form of sulfur released into the atmosphere through sea air gas exchange. The polar oceans are known to be the most productive ocean in terms of DMS due to the high abundance of DMS producing phytoplankton. The oceanic emission of DMS into the marine atmosphere has received increasing attention during the last 30 years because of its possible contribution to cloud formation and its subsequent impact on climate. However, the climate role of DMS remains largely unknown because of lack of evidence supporting DMS derived formation of aerosol particles and their subsequent activation into cloud condensation nuclei (CCN). The Arctic and Antarctic Oceans are facing drastic regional warming, thereby, these regions undergo rapid environmental changes (i.e., increasing temperature, acidification, sea ice decline, shallowing mixed layer depth). These changes may cumulatively have cascading effects on biogenic DMS emissions and sulfur aerosol formation. We recorded and analyzed the atmospheric DMS mixing ratios at Arctic ( Ny Ålesund , Svalbard; 78.5 N,11.8 E) and Antarctic (King Sejong Station; 62.1oS, 58.5oW) sites during phytoplankton bloom periods and found varying regional relationships between the atmospheric DMS and the extent of exposure of the air mass to the phytoplankton biomass in the ocean surrounding the observation site. Furthermore, the connection between biogenic DMS and the formation of aerosol particles in the Arctic and Antarctic atmosphere was evaluated by analyzing atmospheric DMS mixing ratios, aerosol particle size distribution, aerosol chemical composition and satellite derived estimates for oceanic biological characteristics data. The results indicate that oceanic DMS emissions could play a key role in the formation and growth of aerosol particles.
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