Advance in Research on Carbon Cycling in Wetlands
SONG Chang-Chun ( Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun, Jilin 130012)
Wedands have an important role in storing carbon and the carbon stored in which accounts for 15% of the total terrestrial carbon storage. The area of wetlands decreased rapidly due to climatic change and human activities. The normal hydrologic cycling process and carbon cycling process have been changed and the evolution of wetlands maybe a very important factor that is responsible for the rise of global CO2. Climatic condition is the main driving factor of carbon biogeochemical cycling in wetlands. Carbon cycling in wetlands distinguishes from that in other types of ecosystems because of special eco-hydrological process and soil environment. The key factors influencing carbon accumulation and decomposition are vegetation community, temperature and hydrological conditions ( especially water table). Transpiration of soil and vegetation has positive correlation with the soil temperature and increases linearly as water table decreases. Similarly, flooding can increase CO2 emission of wetlands and hydrological process of wetlands determines the input and output of dissolved organic carbon.