Effects of anthropogenic activities on soil microbial community structure and methane anaerobic oxidation rate in coastal wetlands of Yellow River Delta, China

Abstract

Anaerobic oxidation of methane (AOM) is widely recognized in wetland soils as an important sink for methane (CH₄), a potent greenhouse gas, and an important pathway for CH4 reduction. However, the process of AOM in coastal wetland soil in the context of various anthropogenic impacts and the impacts on microorganisms are not clear due to the intricate interplay among numerous factors in nature and the impacts of anthropogenic activities. Therefore, in this study, laboratory culture methods integrated with molecular biology techniques were used to investigate the rate of AOM in soils of different depths under the influence of several typical anthropogenic activities in the Yellow River Delta, as well as the mechanisms of influence on environmental and microbiological factors. The findings of the study indicated that AOM rates decrease with depth; the effects of various forms of nitrogen (N) on the anaerobic oxidation of soil methane in different soil horizons were inconsistent; and inorganic nitrogen (NH₄⁺, NO₂¯) was found to affect AOM processes by influencing some of the functional communities (ANME-2d, ANME, and Geobacter), as well as some microorganisms (Euryarchaeota, Methanosarcinales) that indirectly affect the AOM process. Moreover, Geobacter, ANME, and ANME-2d were the key functional microorganisms influencing the AOM process in the anthropogenic samples and served as crucial factors in the AOM process. Therefore, this study could provide data support and a theoretical basis for mitigating global warming.