Ocean phytoplankton are a significant source of dimethyl sulfide (DMS), influencing marine cloud formation. Model studies suggest that Arctic sea ice decline might increase DMS emissions, but observational evidence is lacking. This study presents a high-resolution 55-year ice core record of methane sulfonic acid (MSA) flux (a DMS oxidation product) from southeast Greenland. Springtime MSA fluxes correlate with Irminger Sea chlorophyll-a concentrations, while summertime fluxes were three to six times higher from 2002–2014 than 1972–2001, attributed to earlier sea ice retreat and increased chlorophyll-a in coastal waters.

Yutaka Kurosaki, Sumito Matoba, Yoshinori Iizuka, Koji Fujita, Rigen Shimada