New Insights into Volatile Methylated Sulfur over the Southern Ocean

A new study from the Multidisciplinary Investigations of the Southern Ocean (MISO) voyage has revealed that physical-biogeochemical controls on climatically relevant sulfur gases differ markedly across the Southern Ocean and Antarctic coast. Atmospheric dimethyl sulfide (DMS) and methanethiol (MeSH) are important precursors of climate-cooling sulfate aerosol, but their sources, chemistry and fate remain poorly understood. During the 2024 austral summer voyage, extreme DMS episodes near the Antarctic coast were strongly related to recent air mass exposure to highly biologically productive waters, while MeSH exhibited different controls like heterotrophic activity and photo-physical conditions. Over the open Southern Ocean, DMS and MeSH were tightly coupled, but biological productivity alone could not explain their variability; instead, physical ocean structure and atmospheric boundary-layer conditions played an important role. These findings provide new insights into the marine sulfur cycle and support coupled, regime-aware approaches to improve aerosol and cloud representation in Southern Ocean climate models.

Reference: Mynard, C., Franklin, E. B., Alroe, J., et al. (2026). Drivers of atmospheric volatile methylated sulfur variability across the Southern Ocean and Antarctic coast. Atmos. Chem. Phys., 26(16), 11583–11604. https://doi.org/10.5194/acp-26-11583-2026