The Geochemical Characteristics Of Organic Carbon In The Wuliangsuhai Lake And Daihai Lake

This study was carried out on the different mechanism of carbon form distribution in the sediments of the Wuliangsuhai Lake (WLSH) and the Daihai Lake (DH), where are representative on the different mechanism and characteristic of eutrophication. The distribution of organic carbon form and microorganism biomass in sediments of the two lakes are studied, which includes the impacts of environmental factors on the distribution of organic carbon form and microbial biomass, the pulling function to the carbon cycling of the lake ecosystem by the eutrophication levels and types. The results are described as follows:1. First carried out on the simulation experiment on the process of the organic matter degradation, and analyzed the dissolved carbon and microbial biomass dynamic change trend, to support the data to the contributions of organic carbon of the carbon cycle.2. The speciation of organic carbon distributions in sediments show that the speciation concentrations of organic carbon of WLSH are lower than that of DH, but LFOC/TOC value is lager than that in DH, so that light-fraction of organic matter of WLSH sediments is more important to the carbon cycling than that of DH.3. PQ value can reflect the degree of humification. The lager of the PQ values the higher of degree of humification, contrarily, the lower of degree of humification. From the PQ value of two lakes we can see that, the PQ value of WLSH is lager than that of DH, so that the humus of WLSH sediments is less important to the carboncycling than that of the DH.4. The microbial biomass of the WLSH are lower than those of the DH; the microbial biomass in the southeast of the WLSH are higher than those in other part of the WLSH; the microbial biomass in the middle of the DH are higher than those in the lake shoal of the DH.