Effects of salinity on methane emissions and methanogenic archaeal communities in different habitat of saline-alkali wetlands

The increase in temperature caused by global climate change has promoted the salinization of wetlands. Inland saline-alkaline wetlands have an environment of over-humidity and shallow water and are hot spots for CH 4 emissions. However, there are few reports on the effect of salinity on CH 4 emissions in inland saline-alkaline wetlands. This study conducted simulation experiments of increased salinity to investigate the impact of salinity, habitat, and their interactions on CH 4 emissions, as well as to examine the response of methanogenic archaea to salinity. Overall, salinity inhibited CH 4 emissions. But there were different responses in the three habitat soils. Salinity decreased the relative abundance of methanogenic archaea and changed the community structure. In addition, salinity changed soil pH and dissolved organic carbon (DOC) and ammonium (NH 4 + ) concentrations, which were significantly correlated with methanogenic archaea. Our study showed that salinity changed the soil physicochemical properties and characteristics of the methanogenic archaeal community, affecting CH 4 emissions.