The survey of phytoplankton density fluctuation in Dong Nai river (from Song Be river to An Hao wharf)

Abstract

Dong Nai river is known for its important role in the economic development of Vietnam such as the main water supply for the South-East region of Vietnam, hydropower development, especially capture fishery. One of the problems to be concerned is the fishery resources and their impact on Dong Nai river. Phytoplankton has been known as an important component involved the food chain, as well as a reflection factor of the water environment quality. The study of phytoplankton will contribute important information in the evaluation of the biodiversity and environmental quality in Dong Nai river. Therefore, study was conducted to evaluate the variation of phytoplankton density in Dong Nai river. The research on the phytoplankton density was studied from 32 samples collected in March, June, August and December 2014 at 8 locations of Dong Nai river (from Song Be river to An Hao wharf). The species compositions of phytoplankton included 145 taxa of Cyanophyta, Chrysophyta, Bacillariophyta, Chlorophyta, Euglenophyta, and Dinophyta. The dominant genus were Staurastrum, Cosmarium, and Melosira. The phytoplankton density ranged from 10,709 to 201,258 individuals.L. The densities in March and June were higher than those in September and December.