High concentrations and turnover rates of DMS, DMSP and DMSO in Antarctic sea ice

The vast Antarctic sea‐ice zone (SIZ) is a potentially significant source of the climate‐active gas dimethylsulfide (DMS), yet few data are available on the concentrations and turnover rates of DMS and the related compounds dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) in sea ice environments. Here we present new measurements characterizing the spatial variability of DMS, DMSP, and DMSO concentrations across the Antarctic SIZ, and results from tracer experiments quantifying the production rates of DMS from various sources. We observed extremely high concentrations (>200 nM) and turnover rates (>100 nM d−1) of DMS in sea‐ice brines, indicating intense cycling of DMS/P/O. Our results demonstrate a previously unrecognized role for DMSO reduction as a major pathway of DMS production in Antarctic sea ice. Key Points Rapid DMSO reduction occurs in Antarctic sea ice Comparatively rapid S cycling and high DMS concentrations occur in sea ice This analytical technique identifies multiple DMS production pathways