The Investigation of the Connections Among Hydrogeological Factors and the Emissions of Two Greenhouse Gases in Lake Sediment

Wet ecosystems are important in terms of global greenhouse gas emissions, where a high soil water content is one of the most typical features. However, the roles of hydrogeological properties in sediment during the emission process of methane and carbon dioxide remain to be researched, especially in lake ecosystems. In this study, through investigating the layered sediment in Chaohu Lake, we discovered that strong correlations exist between the water content and microbial gas emissions (methane and carbon dioxide). To further examine these correlations, a systematic analysis of the hydrogeological properties in sediment, gas emission features, methane bubble emission theories and microbiomics was conducted. The results revealed that microbial methane emissions can influence sediment structure and the interstitial water content. Differently, the similar distributions in different layers probably lead to the correlations between microbial carbon dioxide emission and the water content. This research also discusses the connections with other hydrogeological parameters (particle features, interstitial space, etc.) during the emission process. In addition, this study addresses the significance of methane emissions for the material exchange between overlying water and sediment. The effect of microbial gas emissions on sediment physical-chemical properties also provides meaningful information for researching the relationships among environmental factors and microbial ecology.