Can lower activity of sediment aerobic methanotrophs explain why coastal areas are hotpots for marine methane emissions? The role of animal-bacteria interactions, light and other abiotic drivers

In marine systems, shallow coastal areas are hotspots for methane (CH4) emissions.

Here, much of the CH4 is produced in sediments by methanogenic archaea, but methanotrophs that oxidize CH4 function as an important ‘benthic filter’. Much research efforts focus on the environmental drivers of anaerobic oxidation in marine sediments.

However, how biotic and abiotic factors shaping the sediment surface regulates aerobic methanotrophs are much less understood.

These microbes live in the top layer of sediments with oxygen, a dynamic environment engineered by benthic fauna and by the exposure to light and a myriad of other abiotic factors. There is today a knowledge gap on how such drivers mediate aerobic CH4 oxidation and its consequences to CH4 fluxes.

In this project an ambitious approach is proposed to clarify to what extent aerobic methanotrophy in sediments modulates CH4 emissions from shallow coastal areas. Are CH4 emissions related to the low abundance and activity of sediment aerobic methanotrophs? How are these microbes affected by fauna-bacteria interactions and light exposure in the sediment surface?

The proposed project includes collaboration with scientists from molecular ecology, benthic ecology, and biogeochemistry to tackle these questions.

The aim is to produce important outcomes with the potential to change the current understanding of how ecological interactions drive CH4 dynamics in marine systems and their consequences to climate change.