General Situation of the Study Area -- Freeze-thaw rules of wetland soils -- Dynamics of Dissolved Carbon and Nitrogen in Soils-Water-Ice System during Freeze-thaw Period -- Freeze-thaw Effects on Dissolved Organic Carbon sorption/desorption -- Freeze-thaw Effects on Ammonium Sorption/desorption -- Freeze-thaw Effects on Soil Organic Carbon and Nitrogen Mineralization -- Dynamics of Accumulation and Release of Dissolved Carbon and Nitrogen.

Freezing and thawing of soils is a common phenomenon in the winter-cold zone. The thesis titled “Material Cycling of Wetland Soils Driven by Freeze-Thaw Effects” systematically explores the freeze-thaw effects on the accumulation and release processes of carbon and nitrogen in wetland soils, which is a good step toward the investigation of biogeochemical processes in wetlands in seasonal freeze-thaw areas. It is also developing strategies aimed at global warming effects on the accumulation and release of carbon and nitrogen in wetlands. Dr. Xiaofei Yu works at the Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, China.