湿地占陆地表面积的5%~8%,其碳储量却达到陆地碳库的30%,是一个非常重要的土壤碳库。在气候变化和土地利用变化的影响下,全球约一半的湿地正受到干旱或退化的威胁;人为排水或干旱造成的水位下降很可能将湿地由碳汇变成碳源。但是,在野外观测中,土壤有机碳对湿地水位下降或干旱的响应并不一致,其机理亟待进一步明确。 Wetlands account for 5% to 8% of the surface area of ​​the land, and their carbon storage reaches 30% of the land carbon pool, which is a very important soil carbon pool. Under the influence of climate change and land-use change, about half of the world’s wetlands are under the threat of drought or degradation. The drop of water level caused by man-made drainage or drought is likely to change wetlands from carbon sinks to carbon sources. However, in field observations, the response of soil organic carbon to declining water level or drought in wetlands is not consistent, and its mechanism needs to be further clarified.