Moina macrocopa demographic response to harmful cyanobacteria

摘要

The Virgilio Uribe Rowing Canal in Xochimilco, Mexico City has cyanobacterial blooms throughout the year, often of the genus Microcystis. Here we evaluated the demographic responses of Moina macrocopa in the presence of cyanotoxins obtained by freezing and sonication of blooms collected in June (2017), September (2017) and March (2018). Acute toxicity tests (LC50) showed that the median lethal concentration, on Moina macrocopa was 1.56, 1.30 and 2.56 mu g/L, in June, September and March, respectively. The life table of M. macrocopa was done using 5% and 10% of the LC50, fed on Scenedesmus acutus (0.5 x 10(6) cells/mL) with four replicates per treatment. We found that cyanotoxins reduced the survival and fecundity of Moina macrocopa. The population growth rates ranged from 0.27 and 0.49 d(-1) for the blooms collected in June, 0.38 and 0.52 d(-1) for those of September and 0.42 and 0.52 d(-1) for the blooms in March. We found that most of the cyanobacterial strains of the rowing canal are toxic and may have adverse effects on humans exposed to them daily. (C) 2020 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.