Environmental contextDimethylated sulfur compounds can exert multiple biological and environmental effects including climate regulation. Climate change and other anthropogenic factors are predicted to affect coral-reef ecosystems where these sulfur compounds are particularly abundant. We review the processes that regulate the production of dimethylated sulfur compounds in coral reefs and the potential consequences of environmental changes on their biogenic cycle in such fragile ecosystems under future climate change scenarios. AbstractDimethylsulfoniopropionate (DMSP) and its main breakdown products dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) are biogenic species in the marine environment. In coral reefs, these dimethylated sulfur compounds (DSCs) have been reported at greater concentrations than in other marine ecosystems, which is most likely attributable to the extraordinary large biodiversity of coral reef communities (e.g. corals, macroalgae, coralline algae, invertebrates) and to the unique ability of zooxanthellate corals to synthesise DMSP from both the animal host and algal symbionts. Besides the various biological functions that have been attributed to DSCs, including thermoregulation, osmoregulation, chemoattraction and antioxidant response, DMS is suspected to take part in a climate feedback loop that could help counteract global warming. Nowadays, anthropogenic effects such as pollution, overfishing, increased sedimentation and global climate change are imminently threatening the health of coral reef communities around the world, with possible consequences on the natural cycle of DSCs within these ecosystems. This review provides insight into the biogeochemistry of DSCs in coral reefs and discusses the implications of projected changes in DSC production in these increasingly stressed ecosystems under future climate change scenarios. It shows that DSC dynamics will incontestably be affected in the near future, with possible feedback consequences on local climate.
Differential vulnerability to climate change yields novel deep-reef communities