Relating Dimethyl Sulphide and Methanethiol Fluxes to Surface Biota in the South-West Pacific Using Shipboard Air-Sea Interface Tanks

Using an original experimental setup with deckboard incubations of seawater, emission fluxes of the climate relevant gases Dimethyl sulphide (DMS) and methanethiol (MeSH) were measured in the South West Pacific Ocean during the Sea2Cloud voyage. MeSH contributed 11-18% to the atmospheric sulphur budget. The experiments revealed significant correlations between DMS and MeSH fluxes and nanophytoplankton cell abundance. This highlights the pivotal role of this phytoplankton size class in mediating marine emissions to the atmosphere. The addition of ozone in one of the incubation tanks headspace had a limiting effect on DMS emissions, while no effect on MeSH emissions. These results, published in JGR-Atmospheres journal, provide insights to better constrain sulfur gas emissions in chemistry transport models.
Reference: Rocco, M., Dunne, E., Salignat, R., et al. (2025). Relating dimethyl sulphide and methanethiol fluxes to surface biota in the south-west Pacific using shipboard air-sea interface tanks. J. Geophys. Res.: Atmos., 130, e2024JD041072. https://doi.org/10.1029/2024JD041072