Blooming of harmful cyanobacterium Raphidiopsis raciborskii in Buon Phong reservoir, Daklak province

Abstract

This study investigates species biodiversity composition, morphological characteristics and fluctuation in cell density of cyanobacterial Raphidiopsis raciborskii, and cylindrospermopsin toxin concentration in Buon Phong reservoir. The cylindrospermopsin concentration in the reservoir was identified by using the ELISA test. The results show that 23 species of cyanobacteria in 10 genera, 5 families, 3 orders (Chroococcales, Oscillatoriales, Noctoscales) were identified. Straight filamentous Raphidiopsis raciborskii bloomed all year round in the reservoir with cell densities of 53,6 ×10⁶–58,3 × 10⁷ cells/L. The results of the ELISA test show that cylindrospermopsin toxin in the reservoir existed during the 12 months of the studied period, ranging from 0.04 to 0.72 µg/L. Although the toxin concentration is below the hazard level (1 µg/L), the presence of cylindrospermopsin in the reservoir poses a potential risk because the reservoir water is used for domestic, livestock and aquaculture activities.