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Marques,Paulo Henrique C.; Oliveira,Haydée Torres de; Machado,Eunice da Costa. |
The Piraquara river basin (Upper Iguaçu River basin - Brazil) was studied as an ecological system throughout a complete seasonal cycle, comprising the rainy and dry season. Analyzes of 16 physical and chemical water variables (dissolved oxygen, biochemical oxygen demand, temperature, pH, conductivity, total nitrogen, total phosphorus, ortophosphates, nitrite, nitrate, ammonium, reagent silicate, total suspended solids, chlorophyll - a, flow velocity and depth) showed correlations between water composition and watershed physiographic features, and the Principal Component Analysis allowed to evidence spatial gradients and seasonal differences. The sampling points were clustered in patches with homogeneous behavior, according to ecologycal concepts: patch 1,... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lotic Ecossystems; Water Chemistry; Subtropical Stream; River Continuum; Upper Iguaçu Watershed. |
Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132003000300010 |
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Primavesi,Odo; Freitas,Alfredo Ribeiro de; Primavesi,Ana Cândida; Oliveira,Haydée Torres de. |
The Canchims creek watershed in São Carlos, SP, Brazil, was chosen to evaluate water quality affected by dairy and beef cattle production systems based on tropical pasture. The water samples were collected monthly, during three years, at six sampling points: spring in a tropical forest, spring in an intensive dairy production system, two dam springs, and stream water upward and at the delta. Results showed differences (P<0.01) among sampling points for the mean parameters. True color, hardness, turbidity, electric conductivity, alkalinity, pH, chemical oxygen demand and consumed oxygen explained well differences among sampling points. According to current legislation standards, water quality fitted with most of the established parameters for class 2,... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dairy cattle; Beef cattle; Intensive management; Pasture; Water quality; Watershed. |
Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000200013 |
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