Aerobic methane production data from marine ecosystems

The 13C labelling experiments were conducted with MPn, DMS, and TMA, in which the carbon atom of the methyl group(s) was enriched in 13C enrichment. Preparation of 13C-MPn, 13C2-DMS, and 13C3-TMA was performed by gravimetrically mixing 13C-MPn, 13C2-DMS, and 13C3-TMA with unlabelled MPn, DMS, and TMA at a ratio of 1:99, respectively. A final concentration of 1 mM was used for each methylated compound. All groups were incubated under natural conditions (light and temperature) and manually shook every 6 hours to avoid the “bottle effect”. At 0, 2, 4 and 6 days, water samples for methane analysis were collected in 20 ml glass bottles from all the treatments separately. The samples were analysed immediately after collection. The bottles were immediately sealed with butyl rubber stoppers and aluminium caps. All samples were analysed after 7 days. The incubation experiments were repeated at least three times. The concentrations of methane and carbon dioxide and their stable carbon isotpic signatures were monitored during the incubation experiments.