Response of soil methanogenic bacterial communities to different precipitation gradients in the Bird Island Wetland

Methanogenic bacteria play an important role in the process of wetland CH₄ emission. Changes in precipitation patterns have and will continue to affect the structure and function of wetland ecosystems, affecting the process of wetland CH₄ emission. In this study, the lakeside wetland of Bird Island in Qinghai Lake was taken as the research object, five precipitation gradients were set up, and the mcrA Amplifier sequencing technique was used to detect soil methanogenic bacteria in order to explore changes in their community characteristics in response to to different precipitation gradients. The results showed that the dominant methanogenic bacteria in the soil of Bird Island were Methanomicrobiales, Methanosarcinales, and Methanobacteriales. The prediction of the FAPROTAX function showed that hydrogen-trophic methanogens were dominant in soil, which inferred that H₂/CO₂ reduced to the main pathway of CH₄ production in Bird Island soil. LEfSe analysis showed that five precipitation gradients coexisted with 31 different microflora, and the number of differential microflora was the most under the treatment of 50% precipitation, with 10 different microflora from the order to species level. Overall, the community diversity of methanogens in Bird Island soil was stable, but the community structure was sensitive to changes in precipitation, and the relative abundance of some microflora changed significantly (P < 0.05). The results can provide some reference for predicting the influence of precipitation change on soil carbon cycle in BirdIsland wetland.