A study of dispersal patterns of reef corals in Vietnam under the influence of current regime of Bien Dong

Abstract

Recognizing the flow regime in the breeding season is the dominant factor for the marine biota, a flow diagram of the Bien Dong (East Vietnam Sea) in the transitional season has been established to examine the relationship between the current and its distribution and diversity of reef-forming coral in the sea of Vietnam. The data source for modeling the current regime is updated from the Climate Forecast System Reanalysis of the National Center for Environmental Prediction (NCEP CFSR) and exploited from the HYCOM + NCODA Global 1/12.5 database for the period 1993-2012 and of HYCOM + NCODA Global 1/12o Analysis for the period from 2013 to 2020. Along with that, the finite element method (FEM) was used to build a 3D hydrodynamic model. Based on the constructed flow diagram, the dispersal capacity of coral larvae in each sea area is assessed to compare with previous observations on the species diversity of reef-forming corals. The finding includes: (1) the Gulf of Tonkin and Gulf of Thailand exhibit poor exchange and lower diversity than the continental shelf and coastal waters of Vietnam; (2) Cape Varella is a vital boundary dividing the East Vietnam Sea, forming the most diverse areas in good exchange conditions of water bodies in the south of the 13°N parallel, including the Truong Sa (Spratly) Islands. This system can be considered as part of the Coral Triangle in the Bien Dong.