Advances in the response of surface-subsurface water exchange to activities of typical aquatic organisms in the hyporheic zone of rivers

The river hyporheic zone is the main area of surface-subsurface connection and exchange. Surface-subsurface water exchange promotes the transport and transformation of biogenic substances and can conserve water resources, stabilize regional ecological environment, which provide a great habitat for aquatic life. Therefore, understanding the relationship between the activities of aquatic animals and surface-subsurface water exchange is the key to deep cognition and scientific protection of aquatic ecosystems. This paper reviews previous studies on the feedback of aquatic activities to the surface-subsurface water exchange process, for example, the biofilm formed by benthic microorganisms can absorb or retain biogenic substances, prolonging and changing the migration time and path of substances; the activities of aquatic animals can affect the physical characteristics of riverbed, such as permeability and porosity of streambed, which in turn affect the hyporheic exchange flux and substances transformation efficiency; the block and disturbance of water flow by aquatic plants can also affect the surface-subsurface water exchange process. According to the current researches in this field, three important research directions of the relationship between river hyporheic exchange and aquatic organisms are proposed in this study: the theory of mutual feeding between hyporheic exchange and aquatic organisms; relationship between surface-subsurface water exchange and aquatic ecological function; biogeochemical coupling processes in hyporheic zone.