QUALITY ASSESSMENT OF SOME WATER BODIES IN DONG NAI NATURE – CULTURE RESERVE USING ZOOPLANKTONIC INDICATORS

Abstract

The research investigated water quality in important aquatic ecosystems vital to local biodiversity at the Dong Nai Nature and Culture Reserve. There were 121 zooplankton species in five major groups: Protozoa, Rotatoria, Cladocera, Copepoda, and Ostracoda. The Shannon-Wiener diversity score ranged from 1.1 to 3.68, indicating moderate to severe contamination in all sampling locations (β-mesosaprobic to polysaprobic). Chemical Oxygen Demand (COD) readings in water samples were grade D according to Vietnamese National Standard TCVN 08:2023/BTNMT, indicating polluted aquatic systems. In the study, pollution-indicator zooplankton species such Brachionus calyciflorus, angularis, falcatus, Lecane lunaris, Diaphanosoma brachyurum, Thermocyclops hyalinus, and Keratella cochlearis were widespread. Both biological and physicochemical indices yielded consistent results, however biological indicators were more sensitive to pollution levels. Zooplankton-based biotic indices are essential for ecological monitoring, allowing detailed assessments of aquatic ecosystem health and stability.