Australian scientists have discovered that the coral animal—not its algae symbiont—makes an important sulphur based molecule dimethylsulphoniopropionate (DSMP). DSMP can assist the coral in many ways, ranging from cellular protection in times of heat stress to local climate cooling by encouraging cloud formation.
DSMP is responsible for the “characteristic smell of the ocean”, indicating how abundant the molecule is in the marine environment.
This discovery that corals produce DSMP is the first time an animal has been identified as a DSMP producer. Previously it was assumed that the algae symbiont was responsible for its production. The researchers found that DSMP production increased when corals were subjected to water temperatures that put them under heat stress. DSMP and its breakdown products act as antioxidants protecting the coral tissues from environmental stress. DSMP also serves as nuclei for the formation of water droplets in the atmosphere; thus, its help to create clouds.
A decrease in corals could result in a major decrease in DSMP production, which in turn will limit cloud formation. “Cloud production, especially in the tropics, is an important regulator of climate—because clouds shade Earth and reflect much of the sun’s heat back into space. If fewer clouds are produced, less heat will be reflected — which ultimately will lead to warmer sea surface temperatures,” Dr Raina the lead author explains.
“Considering declining trends in coral cover and predicted increases in coral mortality worldwide caused by anthropogenic stressors, the associated decline in sulphur aerosol production from coral reefs may further destabilise local climate regulation and accelerate degradation of this globally important and diverse ecosystem.” The researchers are from the Australian Institute of Marine Science (AIMS).
The full journal article can be accessed here.