Sulfur Compound Cues Oceanic Snack Time

When phytoplankton release an organosulfur compound called dimethylsulfoniopropionate (DMSP), it’s a beacon for a variety of creatures, including sea urchins, fish, birds, and seals, to come to an oceanic food hot spot to look for a snack. A team of scientists has now resolved a debate about whether marine microbes also find a whiff of DMSP enticing: It turns out, they do (Science 2010, 329, 342). Justin R. Seymour of the University of Technology Sydney, in Australia, and coworkers report that a diversity of bacteria, zooplankton, and other phytoplankton rush toward high concentrations of DMSP and consume it as a source of carbon and reduced sulfur, sometimes producing dimethylsulfide (DMS) as a by-product. In addition to adding clarity to the dynamics of marine food webs, the finding is valuable to climate scientists because cycling of DMSP and DMS is a primary source of sulfur aerosols in Earth’s atmosphere. The aerosols in turn lead to cloud formation and affect global temperatures.