Modelling of the seasonal patterns of dimethylsulphide production and fate during 1989 at a site in the North Sea

This modelling study aimed to extend our understanding of the biogeochemistry of the climatically active gas dimethylsulphide (DMS) in marine surface waters to an annual cycle. Processes involved in the production and fate of DMS and its precursor beta-dimethylsulphoniopropionate (DMSP), a product of phytoplankton synthesis, were incorporated into a complex, coupled one-dimensional physical ecosystem model (European Regional Seas Ecosystem Model (ERSEM) and the General Ocean Turbulence Model (GOTM)) to create a model of DMS biogeochemistry at a seasonally stratified site in the North Sea for 1989. The model was validated against nutrient concentrations, biological standing stocks, biological production, DMS and DMSP concentrations, and DMS sea to air flux determined throughout 1989 during the North Sea Project. The validation results demonstrated that complex ecosystem models, combined with a comprehensive network of processes that control the production and fate of DMSP and DMS, could accurately mimic DMS biogeochemistry. The model provides insights into the impact of seasonally changing physical forcing on the relative contribution of individual processes to DMS production and sea to air flux.