Impact of land reclamation on marine hydrodynamic and ecological environment

Over the last decade, land reclamation with a large scale and fast speed has developed along the Chinese coastline. Land reclamations can earn profits for local economy but also produce significantly negative influences on marine ecosystems. We summarized the impact and mechanism of land reclamation on the marine environment and ecosystem in terms of hydrodynamics, biodiversity, and biogeochemical process. By means of changing its natural geometry (shoreline, geomorphology, and water area), land reclamation impacts ocean hydrodynamic environment (tidal regime and capacity of water exchange) and weakened the environmental capacity of bays. Large scale land reclamation can damage coastal habitat, significantly reduce the biodiversity, and threaten ecosystem structure and function. Meanwhile, the changed hydrodynamics and reduced biodiversity can influence the process of biogeochemical cycle, which will accelerate eutrophication and increase the risk of ecological disaster. The ecological remediation is very critical for reducing the negative impact from land reclamation. Three ecological methods are suggested to do remediation after land reclamation, which include increasing the biomass, establishing natural reserve, and returning the land back to sea. Based on the linear relationship between the ecosystem services and the ecological habitat area, the strategy and policy of ecological compensation are applied for quantifying its economic value. Internationally, based on the above linear relationship, quantitative parameters of ecosystem service and functioning have gradually applied into environmental management. With some nonlinear theories developed, the method of ecological compensation has been more and more reasonable. In China, the quantitative research on the environmental and ecological effect of land reclamation and the practical application of theory in management are still need improved. According to current research status and trend, the cross and integration of natural science and social science may be the most sensible and best way to the synthetically and accurately evaluate the impact of land reclamation on marine environment and ecosystem.