Antarctic intertidal sediments are overlooked hotspots of dimethyl sulfide production associated with Granulosicoccus-containing microbial communities

Dimethyl sulfide (DMS) is a volatile organosulfur compound that contributes to global climate regulation through its role in atmospheric aerosol formation. The Southern Ocean is an important source of DMS and represents a key region for marine sulfur cycling. However, previous studies have primarily focused on pelagic ecosystems, and the microbial drivers of DMS cycling in Antarctic coastal sediments remain poorly understood. Here, we integrated 16S and 18S rRNA gene amplicon sequencing, metagenomics, and DMSP-amendment incubation to characterize the DMS cycling in intertidal sediments of the climate-sensitive Fildes Peninsula. Our results revealed notable potential for DMS production via the DMSP cleavage pathway, in contrast to the demethylation-dominated pelagic ocean. Furthermore, the incubation experiments confirmed rapid DMS generation upon the addition of DMSP. Granulosicoccus , Ilumatobacter , and Cocleimonas were the potential drivers of DMS cycling, with genomic reconstruction demonstrating their roles in the biogeochemical cycles of sulfur and nitrogen. Our findings identify Antarctic intertidal sediments as potential hotspots of DMS production mediated by the DMSP cleavage pathway and Granulosicoccus -dominated microbial communities, necessitating their inclusion in polar biogeochemical models under climate change.