Estudo da comunidade fitoplanctônica como bioindicador de poluição em três reservatórios em série do Parque Estadual das Fontes do Ipiranga (PEFI), São Paulo, SP / Phytoplankton community’s study as bioindicator of pollution in three cascading reservoir system in Parque Estadual das Fontes do Ipiranga (PEFI), São Paulo, SP

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The three shallow cascading reservoir system are located in Parque Estadual das Fontes do Ipiranga (PEFI) Biological Reserve in the southern of São Paulo city where located headwater Ipiranga Stream. The first reservoir is linked to Lago das Garças, a shallow and eutrophic environment, where have become frequent blooms of Cyanobacteria that produce aggressive toxins which cause problems to environment and public health. Objective. This study aimed to analyze the sazonal variation of the phytoplankton community of three shallow cascading reservoir system subsequent of a eutrophic lake and avaliated the water quality. Material and Methods. Samples were collected quarterly during the period of one year (October/2005 to July/2006), in the deepest part of the each lake, in two depths. Morphometric variables (superficial area, perimeter, maximum length and depth), climatic variables (air temperature and precipitation), physical and chemical variables (water temperature, transparence of water, euphotic zone, pH, conductivity, turbidity, dissolved oxygen, biochemical oxygen demand, nutrients), biological variables (total and fecal coliforms, chlorophyll-a, pheopigments, species composition, density, biovolume, cells number and descriptions species) were determined. Qualitative samples were collected at the surface using planktonic net (20 µm) and identificated using a binocular optic microscope. Quantitative samples were obtained by collecting bottle and counting in inverted microscope. Multivariate statistical analysis was applied to calculate the correlations between biological and environmental data. Results. The phytoplankton community was composed of 125 taxons distributed in 12 classes: Chlorophyceae (38,8%) was the main class regarding species richness and density, followed by the Cyanobacteria (23,8%), Euglenophyceae (8,7%), Cryptophyceae (6,3%), Zygnemaphyceae (5,5%), Bacillariophyceae (4,7%) and 11,1% for others classes (Chrysophyceae, Coscinodiscophyceae, Dinophyceae, Xanthophyceae, Craspedomonadophyceae and Fragilariophyceae). Taxons that had appeared during all study are: Microcystis aeruginosa, Cylindrospermopsis raciborskii, Planktothrix agardhii (Cyanobacteria). Cylindrospermopsis raciborskii and Chroococcus minutus are descriptions species and they can be considered bioindicator of pollution because their density are elevated (79,4% of total density). Conclusions. The phytoplankton community as well as the environmental variables responded to the seasonality, predominance of Cyanophyceae in spring and Chlorophyceae in others stations. It didn’t have improvement in the quality of the water during the serie.

ASSUNTO(S)

reservatórios em série eutrofização florações de cianobactérias eutrophication cyanobacterial blooms cascading reservoir system

ACESSO AO ARTIGO

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