Research advances in methane production by river microorganisms

Methane (CH₄), an important greenhouse gas, exerts a substantial influence on global climate change. Rivers are crucial sites for methane production, but the complexity of environmental conditionsin rivers makes it difficult to conduct in-depth research on methane generation by river microorganisms with traditional methods. This article first outlines the basic classification of methanogenic microbes, their distribution and the pathways of methane formation such as the hydrogen nutrition metabolism pathway, the formic acid fermentation pathway, the acetic acid fermentation pathway, the methyl nutrition pathway, and the non-enzymatic reaction pathway. Then, it explores the eight environmental factors affecting the methane production process of river microorganisms: temperature, pH value, redox potential, flow rate and water level, water flow shear force, meteorological conditions, and vegetation type. Subsequently, an overview is provided of the application of molecular biology techniques including PCR technology and high-throughput sequencing, in the study of river microbial methane production. Finally, it points out the problems in current research on methane production by river microorganisms, which are the insufficiency in characterizing river environments, limitations in the application of PCR and sequencing technology, as well as the complexity of data interpretation and analysis. Moreover, it discusses future research on river methane emissions from three directions: the construction and application of river environmental models, the deeper application of molecular biology technology, and knowledge sharing and intelligent analysis, providing new ideas and methods for the exploration on river microbial methane production.