About 6-16% of atmospheric CH₄ emitted from natural sources is derived from lake ecosystems. It is believed that CH₄ is produced in anoxic sediments via methanogenesis. However, recent studies revealed that aerobic planktonic microbes can produce methane through the use of methylphosphonic acid (MPn) by C-P lyase enzyme. But, there is no study examining the effects of cell nutritional conditions (N starved or P starved) on aerobic methane production.

We performed the batch-culture experiments of planktonic microbes to identify the effects of cell starvation on aerobic methane production rates under N and P limited conditions. First, we confirmed aerobic CH₄ production by MPn addition treatment. Moreover, we found that MPn + Ni addition accelerated the aerobic CH₄ production. However, MPn + Pi addition did not increase the CH₄ production, indicating the opportunistic utilization of MPn alternative to Pi under phosphorus limited conditions. The present results suggest that the input of excess N into lake ecosystems promotes the metabolism of MPn by planktonic microorganisms, which leads to increase of aerobic methane production in phosphorus-limited oligotrophic lakes.