Ecology of phytoplankton community in two branches of Billings Reservoir (São Paulo, SP) with different trophic states / Ecologia da comunidade fitoplactônica em dois braços da Represa Billings (São Paulo, SP) com diferentes graus de trofia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The aim of this work was to compare the phytoplankton community composition and diversity in Rio Grande and Taquacetuba branches (Billings Reservoir) and to determinate its controlling factors. Water samples were collected in six depths on February, May, August and November 2005. Physical and chemical variables and the phytoplankton community were analyzed. In Rio Grande, 72 phytoplankton taxa were found, distributed among 7 classes. High diversity and uniformity were observed and water body was classified as oligo/mesotrophic. Relative abundance alternate among Zygnemaphyceae, Bacillariophyceae, Euglenophyceae and Chlorophyceae; among C- e R-strategists e among assemblages D, X1, W1 e T. Vertically, alternation of abundant classes was observed due to morphologic characteristics and/or different physiological requirements. In Taquacetuba, 66 phytoplankton taxa were found, distributed among 7 classes. Low diversity and uniformity were observed and water body was classified as eu/supereutrophic. Cyanobacteria R-strategist dominated, especially S1 e Sn assemblages. Apparently, phytoplankton dynamics in Taquacetuba is controlled by competitive exclusion and disturbs, because cyanobacteria dominance inhibit the growth of other classes, while the high diversity in Rio Grande is kept by the presence of disturbs. These patterns observed can be explained by differences on physical and chemical variables, on water intake functioning and on water destinations. Rio Grande is constantly treated with copper sulfate to control algae biomass and to maintain good water quality to public supply. Although, sulfatation as a palliative measure need to be cautious and more studies are necessary to avoid problems still unknown in long term. Taquacetubas water is transferred without treatment to Guarapiranga Reservoir. It could be compromising the water quality of Guarapiranga, which supply a great part of São Paulo city population.

ASSUNTO(S)

assemblages abastecimento público seasonal and vertical variability water supply fitoplâncton transposição billings-guarapiranga. grupos funcionais variabilidade sazonal e vertical billings-guapiranga water transferation phytoplankton

ACESSO AO ARTIGO

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