Terrestrial dimethyl sulfide: Template for astrobiology

Abstract

Dimethyl sulfide (DMS) is a volatile breakdown product of dimethyl-sulfonio-propionate (DMSP). DMS is synthesized by marine phytoplankton, plays a central role in Earth's sulfur cycle and has growing relevance in astrobiology. DMS formation is mediated by complex microbial, viral, enzymatic and photochemical processes that reflect dynamic interactions within marine ecosystems. Bacterial pathways responsible for DMSP degradation are genetically diverse and ecologically widespread, while viral lysis of phytoplankton contributes to release and recycling of sulfur compounds. Once released into the atmosphere, DMS contributes to sulfate aerosol formation, influencing cloud condensation and planetary albedo - an example of biogeochemical feedback between ocean life and climate. This report reviews terrestrial DMS production, including microbial, viral and abiotic contributions. Given its volatility, detectability and potential biological origin, DMS is considered a promising biosignature candidate in the search for life on exoplanets.

Keywords: Dimethyl sulfide (DMS); Hycean sub-Neptune exoplanets; James Webb Space Telescope MIRI instrument; asteroseismology; astrobiology; atmospheric chemistry; biosignatures; climate feedback; dimethyl-sulfonio-propionate (DMSP); mid-infrared transmission spectra; sulfur cycling pathways; terrestrial marine microbial metabolism; vegetation reflectance; viruses.