Public Research Seminar by Earth, Ocean and Atmospheric Sciences (EOAS) Thrust, HKUST (GZ) - Submarine Groundwater Discharge and Coastal Ocean Acidification - Hydrological and Biogeochemical Cycling along the Terrestrial-Aquatic Continuum in a Changing Environment

Intensifying anthropogenic and climatic disturbances result in substantial changes in hydrological and biogeochemical cycling. However, complex interplays between hydrological and biogeochemical processes have not been adequately investigated, jeopardizing efforts to mitigate environmental changes. In recognition of this challenge, my research has been focused on understanding mechanisms regulating water, carbon, and nutrient cycling along the land-river continuum under environmental changes. My investigations highlight controls of water and nutrients on carbon cycling in forest and wetland ecosystems by limiting plant growth. Terrestrial carbon cycling in return affects water and nutrient cycling through regulating evapotranspiration, runoff, sediment and nitrogen export. Land conversion from cropland to forest reduces streamflow by enhancing water loss through evapotranspiration. Increases in forest cover also lead to reductions in riverine particulate organic carbon and nitrogen fluxes as a result of the protection of soil from erosion by forests. Increased use of chemical fertilizers for crop cultivation has been identified as the primary reason for increases in nitrogen export. Climate variability and change play a dominant role in the temporal variability of riverine water, carbon, and nutrient fluxes. Findings in my research have disentangled complex interactions among water, carbon, and nutrient cycling, and thus provide important implications for effective management of water quantity and quality in the context of environmental changes.