Methane is the simplest hydrocarbon and an important greenhouse gas. It can be formed by microbial decomposition of organic matter under anoxic conditions, by thermal cracking of organic matter at high pressure in the deep subsurface, or by chemical reactions that might occur at the pressures and temperatures of Earth’s upper mantle. Abrupt methane/gas release and seepage of fossil fuels often lead to the development of giant geological structures such as mud volcanoes, which have been documented from marine and terrestrial settings. Melting of permafrost results in methane discharge directly to atmosphere and methane ebullition from terrestrial water bodies and wetlands significantly contribute to the atmospheric methane budget. Methane seepage considerably affects terrestrial and ocean redox chemistry sustaining yet poorly known ecosystems and mineral diagenesis. Furthermore, methane is a major component of natural gas and an important alternative energy source and fuel. The development of new technologies focused on making use of methane emissions provides significant energy, economic and environmental benefits.

The session will put emphasis on recent developments in the quantification of methane fluxes and evaluation of methane sinks in marine and terrestrial environments. A further aim is to highlight the significance of physical, (geo)chemical, (micro)biological, and geological controls governing methane release in ocean, permafrost, wetlands and lake systems. The session intends gathering scientists from the fields of geology, biogeochemistry, (geo)physics, modeling, microbiology as well as ecology, to evaluate our current knowledge of marine vs terrestrial methane turnover, interactions between element cycles and ecosystems, environmental controls and mechanisms. We anticipate synergy between marine and terrestrial sciences and a multifaceted view on methane cycling, associated (bio)geochemical processes and biota as well as related biotopes in the ocean and terrestrial domains.

The session also extends an invitation to all those who are dealing with environmental geo- and bio-engineering of methane emissions, methane as renewable energy source or alternative fuel.