Evidence for global coupling of phytoplankton and atmospheric aerosols

Biological coupling between the ocean and atmosphere may have profound implications for global climate change. Atmospheric aerosols such as dust can directly influence the radiative balance of the earth, but evidence is accumulating to suggest it may also have more subtle effects. Biologically available iron in dust, for example, may stimulate phytoplankton blooms, which then draw down carbon dioxide and emit dimethylsulphide (DMS) to the atmosphere. The latter reacts to form methanesulphonate aerosols (MSA) that may also influence the radiation budget. Such coupling processes have been demonstrated in mesoscale experiments in two HNLC regions of ocean. We present a global analysis of remote sensed data that suggests coupling between phytoplankton and atmospheric aerosols may be more widespread in the world's oceans than previously thought. Collocation of clusters of covarying phytoplankton and aerosols with physical processes is compelling evidence for close biological coupling of ocean and atmosphere.