The production and release of microcystin related to phytoplankton biodiversity and water salinity in two cyanobacteria blooming lakes

Abstract

To find the connections between microcystins and the phytoplankton community, coupled with environmental factors, we investigated 2 cyanobacteria blooming lakes, Lake Taihu (at the center of the Yangtze River Delta, eastern China) and Lake Yanghe (near Qinhuangdao City, northern China). Two years of data, including water quality and the amounts of phytoplankton, microcystins, and the congeners in both algal cells and water, were collected from the 2 lakes during 2013 and 2014. The results showed that both the microcystin quota and release percentage were positively correlated with biodiversity of phytoplankton and the Chlorophyta to phytoplankton ratio, but were negatively correlated with cyanobacteria abundance and the cyanobacteria to phytoplankton ratio; both the microcystin quota and release percentage were closely related to the intensity of competition between cyanobacteria and other phytoplankton; meanwhile, microcystins played a role in the competition between cyanobacteria and other phytoplankton. Salinity had a significantly negative relationship with both cellular and total microcystins, but a significantly positive relationship with the microcystin releasing percentage, indicating that an increase in salinity inhibited the production of microcystins but promoted their release into the aquatic environment. In addition, the average number of microcystins in Lake Yanghe was several times higher than the provisional guideline value adopted by the World Health Organization, indicating a possible health risk to local people. Environ Toxicol Chem 2018;37:2312-2322. © 2018 SETAC.

Influence of Environmental Factors on Occurrence of Cyanobacteria and Abundance of Saxitoxin-Producing Cyanobacteria in a Subtropical Drinking Water Reservoir in Brazil

“…Several environmental factors have been shown to control the MC production in cyanobacteria. Thus, microcystin production is reported to vary with salinity [91,92], temperature [93,94], light intensity [95,96], pH [97,98] and nutrients [99,100]. However, in the Itupararanga reservoir, no significant correlations between environmental variables, MC concentrations and potentially toxic genera were found.…”

Spatial and temporal variability of cyanobacteria in two subtropical reservoirs: community composition, molecular and cyanotoxin analyses

“…as recommended by the World Health Organization (WHO, 2011). Numerous studies reported that microcystin production could vary with the salinity (Jia et al, 2018;Vergalli et al, 2020), temperature (Bui et al, 2018;Walls et al, 2018), light intensity (Wiedner et al, 2003;Xie et al, 2016;Wang et al, 2019), pH (Francy et al, 2016Huang et al, 2019), and nutrients . However, no significant correlations between environmental variables, MC concentrations and potentially toxic genera were found in this study.…”