DMS consists of a single sulfur molecule stuck between two methyl (CH3) groups. Produced by marine and freshwater algae, DMS is a breakdown product of dimethylsulfoniopropionate (DMSP; an osmoregulatory compound) and forms when algal cells lyse. DMS has a very low boiling point, which means that once it’s formed in the water, it readily evaporates.
When DMS evaporates, it oxidizes to form sulfur dioxide, which is an important cloud-forming molecule. An increase in the amount of algae in the ocean would theoretically increase the concentration of DMS in the air and subsequently form more clouds. Clouds do a great job of reflecting incident solar radiation back into space. This increase in the earth’s reflectance (termed “albedo”) would lower global temperatures. The CLAW hypothesis, as this theory is now known, is an acronym for each of the authors’ last names of the original paper (Charlson et al. 1987).
That is where my work comes in. In addition to studying plastic ingestion in procellariiform seabirds, I am also investigating the role these amazing birds play in a marine tritrophic interaction, mediated by the infochemical, DMS. From its humble beginnings as a mere biological waste product, DMS has turned into one of the most well-studied molecules on the planet. An interesting tale, indeed.