Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and potential relevance for the environment [Dataset]

We investigated marine algae as a source of methane (CH4) in oxic surface waters of oceans. The widespread haptophytes Emiliania huxleyi, Phaeocystis globosa and Chrysochromulina sp. were investigated. We performed CH4 production and stable carbon isotope measurements and provide unambiguous evidence that all three investigated marine algae are involved in the production of CH4 under oxic conditions. In cultures that were treated with 13C-labeled hydrogen carbonate, 13C values of CH4 increased with incubation time, resulting from the conversion of 13C–hydrogen carbonate to 13CH4. The addition of 13C-labeled dimethyl sulfide, dimethyl sulfoxide, and methionine sulfoxide – known algal metabolites that are ubiquitous in marine surface layers – resulted in the occurrence of 13C-enriched CH4 in cultures of E. huxleyi, clearly indicating that methylated sulfur compounds are also precursors of CH4. We propose that haptophyte mediated CH4 production could be a common and important process in marine surface waters.