Oxic methane formation in dimethyl-sulfide-enriched lake waters

Accumulations of CH4 in well-oxygenated lake waters have been widely reported but the mechanisms behind this methane paradox remain elusive. One explanation involves CH4 generation from dimethyl sulfide (DMS), produced from dimethylsulfopropionate (DMSP) released by phytoplankton. To test this hypothesis in a freshwater system, microbial community structures in the upper toxic water column of two basins of Lake Lugano have been followed by 16S rRNA amplicon sequencing. The community structures are linked to phytoplankton blooms and associated production of DMS and methane in the toxic water.