Phytoplankton structure in two contrasting cascade reservoirs (Paranapanema River, Southeast Brazil)

Abstract

A series of eleven reservoirs was constructed in the Paranapanema River, southeast Brazil, for hydropower production. The phytoplankton structure and its relations with the environmental variables were studied in two of these reservoirs: a large upstream located storage system (high water retention time) and a small run-of-river system (short water retention time). The samples were collected quarterly for two consecutive years, at four sampling stations in each reservoir. Higher phytoplankton richness was observed in the semi-lotic compartments. Higher values of diversities were observed in the upper region of the run-of-river reservoir, under the influence of the larger storage reservoir discharges, and lower values were observed in deeper layers of this same reservoir. The pronounced variation on seasonal rain precipitation and operational water releases, retention time and quota had major influence in the phytoplankton assemblages. The influence of other environmental variables was also indicated by a canonical correlation analysis. Chlamydophyceae, Dinophyceae, Zygnemaphyceae, Chrysophyceae, Chlorophyceae, Bacillariophyceae and Cyanobacteria were positively correlated with higher transparency and depth; Euglenophyceae with temperature and Cryptophyceae with total phosphorus, dissolved oxygen, conductivity, turbidity, total nitrogen and total suspended solids. The influence of the storage reservoir on the phytoplankton of the downstream run-of-river reservoir was more evident in the dry period. During the rainy period the lateral tributaries effects seems to have a higher influence, especially on the smaller studied reservoir.

Climate factors and limnological conditions shaping phytoplankton community in two subtropical cascading reservoirs

“…Slight Increased water retention time was important in structuring Itaúba reservoir with marked decrease of species richness and increase in dominance of a few species. Increased cell density related to increased water retention time, was also described for other Brazilian reservoirs (Ferrareze & Nogueira, 2006;Perbiche-Neves et al, 2011). Such environmental conditions favored the development of Ceratium furcoides in high densities, a species adapted to longer water retention periods.…”

Spatiotemporal dynamics of C and N isotopic signature of zooplankton: a seasonal study on a man-made lake in the Mediterranean region

“…The biodiversity and conservation of such reservoirs are particularly sensitive to climate change (Moss et al, 2009) and are considered as stressed environments (Leira and Cantonati, 2008 and references therein;Naselli-Flores, 2003;Henry et al, 2011;Perbiche-Neves et al, 2011). Compared with natural lakes, artificial waterbodies are subject to severe fluctuations in the water level from seasonal and interannual climatic variations, as well as abstraction for irrigation, hydropower and drinking water.…”

Copépodes (Crustacea, Calanoida, Cyclopoida) planctônicos em reservatórios profundos e dendríticos: efeitos do tempo de residência e da idade de formação

“…compartimentalização espacial, como observado para os cladóceros (Perbiche-Neves & Nogueira, 2010) e fitoplâncton (Perbiche-Neves et al, 2011). Zonas lacustres, intermediárias e lóticas costumam ser identificadas em reservatórios, e a mistura de águas intermediárias ou lacustres com desembocadura de tributários (ponto MSC, por exemplo) podem ocasionar elevados valores de diversidade (H').…”