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

摘要

Many urban lakes in Mexico City such as Lake Chapultepec are infested with high densities of cyanobacteria, particularlyMicrocystis. We tested the effect of cyanotoxins from cyanobacterial crude extracts on the demographic variables of zooplankton. The rotifersBrachionus havanaensisandBrachionus calyciflorus, and the cladoceransCeriodaphnia dubiaandMoina macrocopawere used for the assays. Temperature effects on the response ofB. calyciflorusand 2 clones ofM. macrocopawere 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 ofMoinapreviously exposed to cyanobacteria from Lake Chapultepec would be more resistant to the cyanotoxins. Demography experiments showed thatB. havanaensiswas more sensitive thanC. dubia. The negative effect of the cyanobacterial crude extract onB. calycifloruswas greater at 30 degrees C than at 20 degrees C or 25 degrees C. The strain ofM. macrocopaisolated 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.Environ Toxicol Chem2020;00:1-11. (c) 2020 SETAC