|Title||Responses of a tropical micro-crustacean, Daphnia lumholtzi, upon exposures to dissolved toxins and living cells of cyanobacteria|
|Author(s)||Vo, Thi My Chi; Bui, Ba Trung; Wiegand, Claudia; Dinh, Khuong V.; Dao, Thanh Son|
|Source||Environmental Technology and Innovation 19 (2020). - ISSN 2352-1864|
|Department(s)||Aquatic Ecology and Water Quality Management|
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Acute lethal concentration - Clutch size - Cylindrospermopsis curvispora - Microcystins - Reproduction - Survival proportion|
The mass development and expansion of cyanobacteria release cyanotoxins in the aquatic environment and cause serious problems for grazers such as micro-zooplankton. In contrast to aquatic ecosystems in temperate regions, impacts of cyanobacteria and their toxins on tropical micro-crustaceans are relatively understudied. In this study, acute and chronic effects of pure microcystin-LR (MC-LR), a crude extract of water bloom sample with a dominance of Microcystis aeruginosa containing microcystins (MCE) and living cells of Cylindrospermopsis curvispora were tested on a tropical micro-crustacean, Daphnia lumholtzi. The 24 h- and 48 h-LC50 values for MC-LR ranged from 247–299, and 331–409 μg MCE L−1, respectively. Exposures to 1–25 μg MCE L−1 decreased survival, fecundity, and reproduction of D. lumholtzi. The impacts of C. curvispora cells on life-history traits of D. lumholtzi were density-dependent and more severe than the impacts of dissolved microcystins. It could be that the adverse effects of C. curvispora on D. lumholtzi are linked to a combination of potential toxic metabolites, mal-nutrients, feeding and swimming interference. Daphnia lumholtzi used in this study is more sensitive to microcystins compared to Daphnia species from temperate regions. Therefore, we highly suggest using D. lumholtzi as a model species for toxicity testing and monitoring on water quality, particularly in tropical countries.