Karst carbon sink processes and effects: A review

On shorter time scales, the karst carbon cycle coupled with photosynthesis, is a potential carbon sink. The surface water biological carbon pump (BCP) plays an important role by transforming dissolved inorganic carbon (DIC) to organic carbon (OC), forming a stable carbon sink through a series of biogeochemical processes on shorter timescales (i.e., years to thousands of years). A comprehensive understanding of the karst carbon sink (KCS) is important in understanding its role in the global carbon budget and carbon neutrality. In this paper, we review the current progress and prospect future research of KCS. The world is facing a quick change in climate and rapid variation in land-use, so the interaction mechanism between the above two and KCS needs to be further understood. Manual intervention to increase KCS also deserves attention. Meanwhile, due to the complexity of the karst system and karst carbon cycle, a comprehensive (water, rock, soil, atmosphere, biology) karst carbon cycle monitoring system needs to be established, integrating different types of carbon sink (e.g., soil, forest, karst) under a research framework. An in-depth understanding of these aspects will help KCS better serve the sustainable development of human society.