Space-temporal dynamics of limnological variables in a floodplain wetland located at Ribeira do Iguape Valley (S o Paulo, Brazil) at different hydrological periods Dinamica espa o-temporal de variáveis limnológicas em uma área alagada localizada no Vale do Ribeira do Iguape (S o Paulo, Brasil) em diferentes períodos hidrológicos

AIM: The main goal of this research was to investigate the influence of the hydrological pulses on the space-temporal dynamics of physical and chemical variables in a wetland adjacent to Jacupiranguinha River (S o Paulo, Brazil); METHODS: Eleven sampling points were distributed among the wetland, a tributary by its left side and the adjacent river. Four samplings were carried out, covering the rainy and the dry periods. Measures of pH, dissolved oxygen, electrical conductivity and redox potential were taken in regular intervals of the water column using a multiparametric probe. Water samples were collected for the nitrogen and total phosphorus analysis, as well as their dissolved fractions (dissolved inorganic phosphorus, total dissolved phosphorus, ammoniacal nitrogen and nitrate). Total alkalinity and suspended solids were also quantified; RESULTS: The Multivariate Analysis of Variance showed the influence of the seasonality on the variability of the investigated variables, while the Principal Component Analysis gave rise in two statistical significant axes, which delimited two groups representative of the rainy and dry periods. Hydrological pulses from Jacupiranguinha River, besides contributing to the inputs of nutrients and sediments during the period of connectivity, accounted for the decrease in spatial gradients in the wetland. This "homogenization effect" was evidenced by the Cluster Analysis. The research also showed an industrial raw effluent as the main point source of phosphorus to the Jacupiranguinha River and, indirectly, to the wetland; CONCLUSIONS: Therefore, considering the scarcity of information about the wetlands in the study area, this research, besides contributing to the understanding of the influence of hydrological pulses on the investigated environmental variables, showed the need for adoption of conservation policies of these ecosystems face the increase anthropic pressures that they have been submitted, which may result in lack of their ecological, social and economic functions. OBJETIVO: O objetivo desta pesquisa foi investigar a influência dos pulsos de inunda o sobre a dinamica espa o-temporal de variáveis físicas e químicas em uma área alagada adjacente ao Rio Jacupiranguinha (S o Paulo, Brasil). Onze pontos de amostragem foram distribuídos entre a área alagada, incluindo um tributário pela margem esquerda e o canal do rio adjacente; MéTODOS: Quatro campanhas de amostragem foram realizadas, cobrindo os períodos seco e chuvoso. Medidas de pH, oxigênio dissolvido, condutividade elétrica e potencial redox foram realizadas e