Effects of eutrophication on size and biomass of crustacean zooplankton in a tropical reservoir

Abstract

This is a long-term study (1993-1998) on the effects of increasing eutrophication on the crustacean zooplankton structure in a eutrophic reservoir. The study first demonstrates that the eutrophication increase verified is a phenomenon well described by a single abiotic variable: total phosphorus. During the study period, zooplankton suffered extensive qualitative and quantitative changes. Significant size and biomass responses of certain zooplankton groups to the temporal variations of total phosphorus were found. These findings suggest that the variables size and biomass of major zooplankton groups should always be considered simultaneously in order to assess impacts caused by eutrophication on the structure of zooplankton.

Determination of eutrophic areas in Mundaú/Manguaba lagoons, Alagoas-Brazil, through studies of the phytoplanktonic community

“…Sendacz et al (2006) presented data on zootoplankton biomass and trophic conditions in reservoirs in São Paulo state and conclude that different patterns of numerical densities and levels of biomass occurred with various trophic conditions. The results of this paper concur with the findings, as well as those of Pinto-Coelho et al (2005). The high phytoplanktonic density values obtained in Mundaú and Manguaba Lagoons characterized the two lagoons as strongly impacted environments.…”

Cage culture with tilapia induces alteration in the diet of natural fish populations: the case of Auchenipterus osteomystax

“…However, there is little effort in determining the impacts that may be caused to aquatic environments, such as destruction of natural habitats, eutrophication (carrying capacity), introduction of alien species or decrease in genetic variability, changes in the structure and dynamics of the biota, with possible local extinctions (Agostinho et al, 1999a;Alves e Baccarin, 2005;Schober, 2005). Among all these factors, eutrophication is the most important modification induced by humans (Pinto-Coelho et al, 2005) and there are few studies evaluating its effects on biodiversity for the neotropical region (Crossetti et al, 2008). In spite of the paucity of information on the impact that caging has on aquatic biota and the multiple uses of public waters, this type of aquaculture has been strongly supported by governmental agencies and hydropower companies.…”

Zooplankton community resilience and aquatic environmental stability on aquaculture practices: a study using net cages

“…Previous studies during 2001 (Lansac-Tôha et al, 2005), 2004 recorded similar abundances that were observed in the beginning of this study (T0) in the same reservoir (original conditions of the environment). In general, the nutrient input in the aquatic environments may act as a disturbance that produces a pulse effect and renders the environment more productive, consequently increasing the abundance and biomass of plankton organisms (Angeler et al, 2000;Carpenter et al, 2001;Pinto-Coelho et al, 2005). In the net cage culture, management involves a continuous addition of energy into the aquatic environment due to daily feeding.…”