Advancements in studying the biogeochemistry of methane in marine depositional systems through trace element geochemistry

The habitable planet, shaped by geological processes and microbial activity, is currently threatened by global warming. Methane, as an important greenhouse gas, is responsible for 20% of global warming. The largest amount of methane on the Earth is found in marine sediment. In these methane-rich marine environments, microbial process such as methanogenesis, anaerobic methane oxidation, and aerobic methane oxidation play a crucial role. In this review, the methane cycle mediated by enzymes or coenzymes containing trace elements was analyzed from the perspective of geological microbiology, the potential trace element demand of microorganisms was examined, and the geochemical evidence of trace elements and isotopes that primarily related to the study of the marine methane cycle in recent years were emphasized. At present, the pure culture of microorganisms involved in the methane cycle presents challenges, and to accurately describe biogeochemical processes in geochemical research is difficult. Therefore, interdisciplinary research that combines microbiology and geochemistry offers clear advantages and promising prospects. Understanding the interplay between microbial activities and trace elements in marine methane-rich environments is crucial for investigating the marine methane cycle and regulating global methane emissions in the context of current global warming. Additionally, this knowledge is anticipated to offer a distinctive vantage point for analyzing historical methane emission events and their global ecological/environmental impacts.