ESTIMATING AQUIFER CONTRIBUTIONS TO CARBON CYCLE BUDGETS BASED ON DISSOLVED ORGANIC MATTER CHARACTERIZATION IN KARST AQUIFERS

摘要

Global carbon cycle budgets developed by the Intergovernmental Panel on Climate Change and others disregard the flux of organic and inorganic carbon through continental aquifers (Zhu et al., 2010), even though 97% of the world's liquid freshwater occurs as groundwater (van der Leeden et al., 1990). Recent studies indicate that inland waters, including lakes, reservoirs, rivers, and aquifers, receive twice as much terrestrial organic carbon as dissolved and colloidal organic matter compared to the oceans (Cole et al., 2007; Tranvik et al., 2009). One of the reasons for limited inclusion of continental aquifers in global carbon cycles is because the processes involved in carbon transformation and storage in aquifers are poorly understood, mostly due to the inaccessibility of aquifers and the lack of model systems (Danielopol et al., 2003). However, carbonate caves offer venues for carbon cycle studies as aquifer systems can be directly accessed for experimentation and observation, and the alteration or generation of organic matter can be linked to specific chemical and physiological processes.