The nitrogen dynamics within river watersheds have been profoundly altered by climate change and human activities, significantly affecting the transport and cycling of this essential nutrient into estuarine and coastal environments. These changes can lead to detrimental consequences for marine ecosystems, such as eutrophication, hypoxia, and acidification. Despite the significant implications, the complex interplay of nitrogen cycling between rivers and coastal areas is not yet fully understood. This study concentrates on the land-sea interface, using the Jiulong River-Estuary-Xiamen Bay system as a case study. Our findings reveal that the transport and concentration of dissolved inorganic nitrogen along the river-estuary-coastal continuum follow a nonlinear pattern. The nitrogen dynamics and export, notably through the estuarine turbidity maximum zone, are predominantly influenced by hydro-biogeochemical processes. This research highlights the importance of comprehensive observation, laboratory experimentation, and modeling to better understand the complexities of the watershed-coast ecosystem. It also aims to steer efforts towards achieving a sustainable coastal environment and a healthy ocean.

 

ammonia nitrogen,estuary,eutrophic water,greenhouse gasses