![]() ![]() A short-time previous exposure to cyanobacteria improves the fitness of some cladocerans, which could be transferred to offspring via maternal effects 13, 14, 15. For example, some copepods can avoid the ingestion of toxic cells via detecting cyanobacterial metabolites based on the selective feeding 11, 12. Nonetheless, in the context of “arms-race” hypothesis, the zooplankton develop adaptations to alleviate the harmful effects by cyanobacteria 9, 10. In addition, the colonial or filamentous morphology in cyanobacteria inhibits the grazing activity by clogging the zooplankton filtering apparatus 7, 8. The deficiency in nutrition like sterols and long-chained polyunsaturated fatty acids suppresses the carbon metabolism and thereby declines the zooplankton growth 5, 6. The production of toxic metabolites including microcystins usually causes sublethal or lethal effects for zooplankton survival 4. These aggravated blooms often lead to adverse changes in aquatic ecosystem properties, including toxin production, weakened trophic cascades, and deterioration of water quality 2, 3.Ĭompared with other phytoplankton, cyanobacteria are generally accepted as poor food reducing zooplankton fitness. micrura, which contributes to the diversified zooplankton shifts observed in fields during cyanobacteria blooms.Ĭyanobacteria blooms occur with increased frequency, persistence and wide water ranges due to the eutrophication associated with global warming 1. aeruginosa strengthens the advantage of D. As a result, the competitive advantage of Daphnia became more pronounced, as indicated by the higher Daphnia: Moina biomass ratio with increased Microcystis proportions. ![]() Nonetheless, the population inhibition of Daphnia by competition was alleviated by the increased Microcystis proportion in diet. aeruginosa treatment suppressed the population growths of the two cladocerans, with the reduced carrying capacities. However, the Daphnia was less inhibited with the higher biomass, suggesting the competitive dominance of Daphnia. aeruginosa, the biomasses of the two cladocerans were decreased by the competition between them. No competitive exclusion occurred for the two species under the tested diet combinations. ![]() ![]() aeruginosa, and the rest of green alga Chlorella pyrenoidosa. We evaluated the competitive responses of small Moina micrura and large Daphnia similoides to the presence of Microcystis using mixed diets comprising 0%, 20%, and 35% of toxic M. The influence of Microcystis on competitive dominance by different sized zooplanktons showed species-specific dependence. Microcystis blooms are generally associated with zooplankton shifts by disturbing interspecific relationships. ![]()
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