VARIATION OF SOIL ENZYME ACTIVITIES IN WETLANDS FROM PERMAFROST TO SEASONALLY FROZEN SOIL REGION IN NORTHEAST CHINA

摘要

Soil enzyme activities are sensitive indicators of soil organic matter (SOM) dynamics brought about by climate change. The distribution of soil enzyme activities in wetlands from different types of frozen region in Northeast China was evaluated in this paper. The results showed that the specific enzyme activities of P-glucosidase, invertase, dehydrogenase, urease, and acid phosphatase showed the highest values in seasonally frozen ground indicating faster turnover rate of SOM. Specific activities of invertase and acid phosphatase were higher in discontinuous permafrost than in continuous permafrost. The temperature, SOM and vegetation species regulated soil enzyme activities. Soil dehydrogenase and urease activities increased with soil MBC (microbial biomass carbon) concentrations. P-Glucosidase and acid phosphatase activities were significantly related to DOC (dissolved organic carbon) concentrations suggesting that these two enzymes drive the release of labile components from the SOM. This study helps better understanding relations between soil enzyme and soil labile carbon fractions, and further facilitates the understanding of the stability of soil carbon pool in permafrost wetland of Northeast China.