Abstract:Microalgae play an important role in carbon sequestration in aquatic ecosystems. This review focuses on the proposal of biological carbon pump in aquatic ecosystems at karst areas, the role of microalgae biological carbon pump, the main environmental factors that affect microalgal carbon sequestration, and the research progress in carbon sequestration by microalgae in karst areas. By solving the key scientific problems to be put forward, we can provide the information of in-depth study on biological carbon pump mechanism by microalgae in karst aquatic ecosystems. Besides, the carbon sink potential of karst ecosystems will be scientifically understood and the karst carbon cycle theory also will be enriched.