Expanding ripples in the marine sulfur cycle: scaling up from microscale biological processes to global climate

Abstract

A major portion of the biogeochemical cycling of organic sulfur in the pelagic ocean occurs through dimethylated forms: dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO). The burst of interest in these compounds began with the hypothesized involvement of the volatile species, DMS, in aerosol and cloud formation, hence in climate regulation, over the oceans. This set the need for elucidating and understanding their spatial distribution and temporal dynamics at the global scale, which was hampered by the notion that most of the mechanistic bases occur at the microscale. Indeed, extensive research has revealed that dimethylated sulfur compounds are involved in mechanisms against ecophysiological stress, chemotaxis among plankton microbes, and sulfur transference among trophic levels of planktonic food webs. Molecular tools (including genomics), single cell biogeochemistry methods, and microscale behavior observation techniques are being used to understand the bases of large-­scale patterns that are to be related to climate forcing. Whenever we get lost in the scaling up, the concept of ‘emergent property’ is used as a short cut