The dynamic mechanism of rapid sediment deposition in the mangrove region of the Guangxi Beibu Gulf

The rapid sediment deposition induced by storm and reclamation has both positive and negative effects on the mangrove. In this study, the rapid sediment deposition is found to cause the mangrove mortality in the Tieshan Harbor of Guangxi Beibu Gulf (GBG). Based on modeling and observational results, the reduced tidal current velocity caused by the wharf construction is not the main reason for the mangrove mortality. The sediment generated from the reclamation overflow, accompanied by the effect of entrance avenue, jointly lead to the rapid sediment deposition in the mangrove region and then contribute to the mangrove mortality. Gale process and drainage outlet also make a subsidiary contribution to the rapid sediment deposition. When the entrance avenue was excavated and the reclamation overflow port was moved as well as the drainage outlets were closed, the biomass and perched density of intertidal animals in the mangrove region obviously increased from January to July 2021, corresponding to the decrease of sediment deposition rate during the period.

Automated summary

This study finds that rapid sediment deposition has had a negative impact on the mangrove, leading to mortality. The overflow of sediment generated from reclamation and the influence of entrance channels are identified as the main factors contributing to sediment deposition and mangrove mortality.