Space-temporal dynamics of limnological variables in a floodplain wetland located at Ribeira do Iguape Valley (São Paulo, Brazil) at different hydrological periods

Abstract

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 (São 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.

Exploring factors driving macrophytes in rivers—A case study in Middle Atlas Morocco

“…Similar to other rivers throughout the world that have high fluctuations in hydrochemical parameters (Benassi et al, 2012; Manolaki & Papastergiadou, 2013), the studied rivers proved the presence of variations in several hydrochemical parameters. However, these parameters provide only a partial description of the watercourses.…”

Influence of water fluctuations on the limnological characteristics of two floodplain lagoons (Ribeira do Iguape Valley, state of São Paulo, Brazil)

“…globally impacted ecosystems due to pressure from agricultural and industrial activities, urbanization, and structures for the managing of water resources, which cause changes in their flow regimes (Barliwa, 1995;Jong et al, 2015;Kansiime et al 2007;Rebelo et al 2010). In the Ribeira Valley region (São Paulo, Brazil), aquatic ecosystems have been submitted to an increasing pressure from anthropic activities, represented mainly by agriculture, industrial and mining activities, in addition to impacts caused by the discharge of domestic and industrial effluents (Benassi et al, 2012;Cunha et al, 2010). Since actions for environmental quality management of wetlands in river-floodplain systems should be supported by conservation plans, on a basin scale, that include actions involving scientific knowledge integrated to ecological and socio-economic aspects (Clare et al, 2011;Margules & Pressey, 2000), current study investigates changes in the limnological characteristics of two lagoons in neighboring river basins in response to variations in hydrometric levels of the adjacent rivers.…”