A Long‐Term Study on the Effect of Cyanobacterial Crude Extracts from Lake Chapultepec (Mexico City) on Selected Zooplankton Species

Abstract

Many urban lakes in Mexico City such as Lake Chapultepec are infested with high densities of cyanobacteria, particularly Microcystis. We tested the effect of cyanotoxins from cyanobacterial crude extracts on the demographic variables of zooplankton. The rotifers Brachionus havanaensis and Brachionus calyciflorus, and the cladocerans Ceriodaphnia dubia and Moina macrocopa were used for the assays. Temperature effects on the response of B. calyciflorus and 2 clones of M. macrocopa were tested. We hypothesized that with an increase in cyanotoxin concentration and temperature there would be an increase in the adverse effect on the test species and that the clone of Moina previously exposed to cyanobacteria from Lake Chapultepec would be more resistant to the cyanotoxins. Demography experiments showed that B. havanaensis was more sensitive than C. dubia. The negative effect of the cyanobacterial crude extract on B. calyciflorus was greater at 30°C than at 20°C or 25°C. The strain of M. macrocopa isolated from Lake Chapultepec was more resistant to the cyanotoxins than the strain that had not been previously exposed to the cyanobacteria. The present study indicated that cyanobacteria in Lake Chapultepec are highly toxic and, considering the recreational use of this lake, should be controlled.

The Use of Zooplankton Metrics to Determine the Trophic Status and Ecological Potential: An Approach in a Large Mediterranean Watershed

“…On the other hand, phytoplankton blooms, especially cyanobacterial blooms, can become an additional pressure [61]. Cyanobacteria are a poor-quality food resource [62], produce harmful cyanotoxins [63,64], and can promote zooplankton community shift into small-bodied species [65][66][67]. In comparison to large-bodied species, small species are less mechanically affected (clogging of their filtering apparatus) by the presence of cyanobacterial colonies, mainly of filamentous forms [68] in habitats with a eutrophic increment, where such blooms normally surge [59].…”

Experimental Studies on Zooplankton-Toxic Cyanobacteria Interactions: A Review

“…The adverse effects of cyanobacterial extracts have been studied since the early 2000s [ 30 , 92 ] on several cladocerans including Moina macrocopa , Ceriodaphnia dubia , Ceriodaphnia silvestrii, and Daphnia similis . Ever since, many studies indicate the toxicity of extracts from blooms on rotifers and cladocerans [ 29 , 38 , 39 , 41 , 43 , 93 ]. These studies are based on acute and chronic toxicity tests and data related to survivorship and fecundity of the test zooplankton.…”