Ecotoxicological investigation of cyanobacterial crude extracts to Daphnia magna under subchronic test conditions

Authors : Tanduc Nguyen TANDUC NGUYEN, Xuanquang Ngo XUANQUANG NGO, Thanhluu Pham THANHLUU PHAM, Thanhson Dao THANHSON DAO

Pages : 498-507

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Cyanobacterial blooms often consist of mixtures of microcystin-producing and microcystin-free species, and both can cause unpredictable effects on aquatic organisms. In this work, the subchronic effects of the cyanobacterial crude extracts insert ignore into journalissuearticles values(CCEs); from microcystin-producing and microcystin-free cyanobacteria with different microcystin concentrations insert ignore into journalissuearticles values(1, 10, and 50 mu gLinsert ignore into journalissuearticles values(-1););on Daphnia magna were investigated. The life-history trait responses of D. magna to CCEs were determined based on survival, reproduction, and somatic growth. In addition, the physiological response, represented by the feeding rate of D. magna on green algae insert ignore into journalissuearticles values(Scenedesmus sp.);, after exposure to both types of crude extracts was estimated. Our results showed that both microcystin-containing insert ignore into journalissuearticles values(MCCE); and microcystin-free insert ignore into journalissuearticles values(NCCE); crude extracts insignificantly reduced survival but strongly enhanced reproduction and somatic growth of organisms. However, degradation of eggs and neonates of the gravid females exposed to CCEs was observed. In addition, the feeding rate of D. magna exposed to MCCE increased significantly, whereas no change in the feeding rate was observed for NCCE-exposed D. magna. In general, new and interesting aspects of the toxicity of MCCE and NCCE were revealed by this study, which contributes to the understanding of the toxicity of Pseudanabaena sp. extract on D. magna under bioassays.
Keywords : Cyanobacteria, ecotoxicology, feeding rate, life history traits, somatic growth