Study Of Influence Of Sediment Transport And Distribution On Xiamen Amphioxus Habitat And Protected Areas

Xiamen City is located on the southeast coast of China.The sea area is about 355 square kilometers and has nearly 2,000 marine species.The Amphioxus,as "the agedoriginal species" in Xiamen sea waters,has existed on the earth for about 450 million years.The habitat density and biomass of abundant marine benthic organisms such as the Amphioxus,are closely related to the sediments characteristic contained in the inhabited seabed.Recent years,the rapid development of the Xiamen modernization,involving the activities of seawater dredging,reclamation and sand dumping,has caused seawater turbidity and changes on seabed sediment quality which has a big impact on the Amphioxus habitat and the protected areas.Therefore,in order to protect the Xiamen Amphioxus,investigating on the transport characteristics and siltation distribution of the sediment in the Xiamen Bay sea area through the tidal currents and waves,is of a great scientific contribution to the marine development activities and to protect the marine ecology in Xiamen bay.In this paper,a model of sediment transport in Xiamen Bay governed by the waves and tidal currents forces,is conducted to simulate the sediment movement in Xiamen Bay.Then,based on the qualitative and quantitative analysis from the model results,the seasonal sediment transport characteristics of Xiamen Bay and the distribution of seabed siltation are discussed.Based on the positive and negative correlations between the sediment components contained in the bottom of the seabed and the habitat density and biomass of Amphioxus,this study analyzed and discussed the impact of the sediment transport trend and siltation distribution in Xiamen Bay on the Amphioxus habitat and protected areas.First,establish the Xiamen Bay hydrodynamic model,wave model and sediment transport model by using the data of water depth,sand,etc..And then validated the model using the observation data.Secondly,this study simulated the movement of suspended sediment and bedload sediment in Xiamen Bay.Afterward,the seasonal transport characteristics and the concentration distribution characteristics of suspended sediment are analyzed from the model results,as well as the seasonal silt distribution characteristics of bedload sediment.Finally according to the simulated movement trend of suspended sediment,and the distribution characteristics of siltation of bedload sediments has shown their impact on the Amphioxus habitat and protected areas.It is concluded that the sediment transport and siltation distribution in Xiamen Bay will affect Amphioxus habitats and protected areas.In terms of the trend of suspended sediment movement,the impact of the suspended sediment movement in the east,south and southeast on the habitat and protected areas is to suppress Amphioxus biomass,in terms of silting amount of bed load silt,the impact of very fine sand,coarse-medium sand and gravel-coarse sand on Amphioxus habitats and protected areas is to promote biomass,and the degree of beneficial influence of siltation The index is very fine sand is better than coarse-medium sand is better than gravel-coarse sand.