Forms Distribution Of Inorganic Carbon In Sediments From Dalinuoer Lake And Compared With The Other Three Lakes Of Inner Mongolia Plateau, China

The sediments are important sources and sinks of the global carbon, which plays an important role in the carbon cycle. Among them, the inorganic carbon takes a considerable share. Lakes are abundant in the arid/semiarid region of Inner Mongolia Xin Jiang Plateau, but many of them are salt lakes and saline lakes so that the lake water resources are poor. In recent years, most lakes in the region have quickly becoming salty, area withered and dry, which greatly damaged the ecological environments of the lakes and their catchments. Due to the rich and diverse resources of Inner Mongolia plateau lakes and wetlands, they are crucial to regional economic development and people’s lives. So they occupy an important position in the overall study of China’s lakes and wetlands.This study was carried out on the Dalinuoer Lake (DLNE) Based on the theories and methods of environmental geochemistry, biogeochemistry, pollution ecology and limnology, the geochemical behaviors of inorganic carbon in sediments of the Dalinuoer Lake are studied. The distributions of inorganic carbon forms are analyzed in detail. The influence of C、N、P、Si on carbon cycle in the Dalinuoer Lake is discussed. Furthermore, the forms of inorganic carbon contribution to the carbon cycle of lake ecosystem was qualitative assessed and different form inorganic carbon which can participate in the recycled potential volume was estimated. On this basis, combining the inorganic carbon which has received from phased research achievements of our project team, Selecting Wuliangsuhai Lake、Daihai Lake、 Dalinuoer Lake、Hulun Lake, the different of the mechanism of inorganic carbon content in lake sediments were Discussed. From this work it may provide valuable database for the studies of environmental geochemical cycle and function transformation of source/sink of carbon in lakes sediment. The conclusions reached in this paper are as follows:1. The dominant forms of IC in sediment from DLNE is NH2OH·HCl form. The Potential amount of IC forms contribution to carbon recycling rank as:NH2OH·HCl form> NaCl form> NaOH form> NH3·H2O form. The contributions to carbon cycling of IC forms rank as:NaCl form> NH2OHHCl form> NaOH form> NH3H2O form> HCl form.2. The saturation indexes of calcium carbonate in DLNE lake water over the past three decades were calculated for the first time, which implied have the precipitation conditions of authigenic carbonate. The results showed that the precipitation of authigenic carbonate in cold and arid regions lake was one of the most important mechanisms in the inorganic carbon cycles, the eutrophication level of lake and the photosynthesis of algae were all the significant aspects influencing carbonate precipitation.3. The difference of inorganic carbon geochemistry characteristics were first interpreted in lake sediments from Inner Mongolia plateau. The results revealed that the geographical location and characteristics of lake, the type of lake ecosystems and biomass, the mineralization degree of organic matter and the human disturbance were all the important factors affecting the geochemistry characteristics of lake sediments.