Abstract: In the context of global climate change and human activities, wetlands are facing significant salinization or desalinization, especially in saline wetlands in inland and coastal regions. Wetlands are major natural sources of atmospheric methane. Methane emission of wetlands is the result of production, oxidation and transport of methane. Salts are recognized as one of the key factors controlling methane emission from wetlands. Salinity change may greatly influence watersoil chemistry, plant community composition and productivity, organic matter accumulation rate and microbialmediated biogeochemical processes, thus altering the emissions of methane. This paper reviews the progresses of studies on methane production, oxidation, transport and emission in wetlands. This paper also analyzes the mechanisms of how salts affect the processes of substrate supply, microbial (methanogen and methanotrophs) abundance, activities and community composition, plants, enzyme activities, electron acceptors, soil pH and Eh. Accordingly, five directions are proposed to be considered in the future: 1) integrated studies on the effects of salts on biogeochemical processes of methane emission; 2) coupling influences of salinity background, changing magnitude and speed of salinization on methane emission; 3) how different ions and their diverse associations affect the processes of methane emission; 4) evaluating how salinity affects methanogens and methanotrophs by combing traditional methods based on laboratory culture techniques with molecular biological tools and stable isotope probing techniques; and 5) spatiotemporal variations of the responses of methane emission to salts.

Key words: sand burial, greenhouse gases, biocrust, desert