North Sea and Wadden Sea microbial communities in microcosm incubations with adjusted methane, temperature and salinity conditions

Global warming induced alterations in ocean temperature and precipitation patterns are increasingly impacting coastal ecosystems. In this study, we investigate the resilience and adaptability of aerobic methane-oxidizing bacteria (MOBs) in response to changing environmental conditions. We conducted microcosm incubation experiments with waters from the North Sea and the Wadden Sea collected during different seasons, and explored how variations in methane availability, temperature, and salinity influence the MOB community structure and functional capacity. We observed increased relative abundances of MOBs in experiments with elevated methane concentrations. Temperature and salinity variations exerted smaller effects on MOB composition and relative abundance. A strong effect on MOB community development was furthermore caused by the origin of the inoculum (location and season). Our results suggest functional redundancy in the variable pools of microbial inocula enabling multiple MOB clades to cope with drastic changes in environmental parameters.