Abstract
Natural lakes are significant global sources of CO2 emissions; however, data from lakes in karst regions, which cover 15.2 % of the Earth’s surface, remain insufficiently categorized. This study seeks to elucidate the carbon budget processes and drivers in karst lakes by selecting representative karst and non-karst lakes within the same region. Utilizing high-resolution monitoring, carbon isotope analysis, and mathematical modeling, we investigated the carbon source-sink functions and their controlling factors across different lithologies. Our findings reveal that metabolic processes, quantified using a bookkeeping model, are crucial for driving the diurnal coupling of hydrochemistry and carbon cycling, with karst lakes displaying a pronounced net autotrophic state. Carbon sink fluxes, determined via the boundary layer method, were estimated to be 38 t C km−2 yr−1 for the karst lake, and 11 t C km−2 yr−1 for the non-karst lake. This indicates that despite high dissolved inorganic carbon (DIC) concentrations, the metabolic processes in karst waters, facilitated by their high pH and efficient DIC fertilization, lead to a lower CO2 emission. Furthermore, the low Revelle factor (3.8–4.8) highlights the strong carbonate buffering capacity of karst lakes against CO2. These findings emphasize the capacity of karst lakes to maintain net autotrophy and function as carbon sinks, together with the need to consider lithological differences in future assessments of regional or global lake carbon budgets.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
