The Environmental Character Study Of The CO₂Concentration And Dissolve Inorganic Carbon δ¹³C In Karst Environment

Recently, research of global change is getting more and more concerns from the international community. Problems as temperature rise, sea level ascend which were probably caused by atmospheric greenhouse gases have been put into the government agenda with economic development goals around nations. Geological record plays an essential role in revealing the regularity of paleoclimate, we can benefit in interpreting the environmental information of spelethems through the research. Study of carbon isotopes in the atmosphere and the cave sediments can help us to archive of paleoclimate change. Although stable carbon isotope has been used broadly, valuable records from δ13C are still scarce.In this study, in order to detect the variation characteristics of carbon isotope and to reveal the significations ofδ13C in the reconstruction of paleo-environment, Furong cave karst system were systematically investigated and the CO2concentration of cave air was monitored, too. Several results have been achieved as followings:(1) The relationship of CO2concentration is:CO2concentration in soil>CO2concentration in the cave>CO2concentration outside the cave. CO2concentration in soil has the most intense fluctuation.(2) Continuous monitoring results indicated that the concentration of soil CO2was higher during summer months and lower in winter, the concentration of air CO2outside the Furong cave was lower during summer months and higher in winter. the lowest CO2 in the cave concentration occurred in January.(3) The DIC-813C values of different water in the study area varied with a significant seasonal and spatial characteristic. The DIC-δ13C values of spring water has the largest variation magnitude. The DIC-δ13C values of pool water are obvious heavier than that of drip water, the reason is that pool water have undergone intensive evaporation. The DIC-813C values of soil infiltrating water is lighter than that of spring water and drip water. Because spring water and drip water have Penetrated to rock layer and mixed inorganic carbon of carbonate rock. The DIC-δ13C values of drip water in different position of cave show different changing Patterns, might be relative to different sources and different routes of drip water.(4) It was found that the concentration of HCO3、the pH of karst waters、drop rate and the concentration of CO2in the cave will influence on the DIC-δ13C values of cave waters. Precipitation might have more important influence on the DIC-813C of karst waters than air temperature...