The response of zooplankton assemblages to variations in the water quality of four man-made lakes in semi-arid northeastern Brazil

Abstract

The response of zooplankton assemblages to variations in the water quality of four man-made lakes, caused by eutrophication and siltation, was investigated by means of canonical correspondence analysis. Monte Carlo simulations using the CCA eigenvalues as test statistics revealed that changes in zooplankton species composition along the environmental gradients of trophic state and abiogenic turbidity were highly significant. Brachionus calyciflorus, Thermocyclops sp. and Argyrodiaptomus sp. were good indicators of eutrophic conditions, whereas B. dolabratus, Keratella tropica and Hexarthra mira were good indicators of high turbidity due to suspended sediments. Overall, our results showed that changes in the water quality of man-made lakes in a tropical semi-arid region have significant effects on the structure of zooplankton assemblages that can potentially affect the functioning of these ecosystems.

Zooplankton assemblages in eutrophic reservoirs of the Brazilian semi-arid

“…This differentiation was previously observed by Sousa et al (2008), and our results in MDS analysis confirm this taxonomic heterogeneity in the reservoirs.…”

“…These reservoirs differ in many parameters, but all share low transparencies, as a consequence of high turbidity. In tropical semi-arid regions, the droughts and the irregularity of rainfall, responsible for the annual and inter-annual instability of the rains, together with high evaporation rates, shallow soils, and large drainage-basin areas are key factors in controlling water quality and ecological processes in the reservoirs (Sousa et al, 2008).…”

“…One of the first studies relating zooplankton and environmental conditions of the reservoirs were conducted by Sousa et al (2008) and Vieira et al (2009), who described how variations in water quality can influence the zooplankton composition. In the present study, we aimed to identify the zooplankton structure and composition in eutrophic reservoirs of the state of Rio Grande do Norte in northeast Brazil, and to identify the principal factors that influence the taxonomic and quantitative structure of the zooplankton community in these enriched aquatic systems.…”

Zooplankton communities of two lake outlets in relation to abiotic factors

“…In lakes, stronger correlations between the zooplankton community and abiotic factors are observed, in particular those characterising the water chemistry [11,44,45]. In contrast, in water courses, zooplankton abundance is correlated more strongly with physical parameters, mainly river regime [31,46].…”

Seasonal evolution of the zooplankton community in two riverine wetlands of the Ticino River (Lombardy, Northern Italy)

“…Despite the anthropogenic pressure and a complete absence of submerged vegetation, the zooplankton community in the SL is composed of the same pool of species that we detected in the TO (see Table 2), but the dominant species was the juvenile form of the copepod T. dybowskii, a widespread copepod which generally inhabits small water bodies (Maier, 1990); high abundance of this species could be interpreted as a sign of eutrophic conditions (Sousa et al, 2008). In spring 2012, we also observed a demographic explosion of b-mesosaprobic rotifer species (e.g., Asplanchna priodonta, Brachionus angularis and B. calyciflorus) which became the most abundant group of the community (Sla´decˇek, 1983).…”