Temporal and Spatial Variation of Thermal Profile and its Effect on the Chemical, Biological and Physical Parameters in the Subtropical Reservoir of Sal to Santiago-Parana-Brazil

The thermal profile of reservoirs is important in the distribution of chemical and biological compounds. The purpose of this study is to evaluate the spatial and temporal variation pattern of the thermal profile of the Salto Santiago reservoir during summer and winter in different points and to study the relationship between this structure and some physical, chemical and biological variables in four collection points. Temperature and oxygen sample collections were made onsite every meter from the surface to the bottom. Other variables such as pH, chlorophyll a, suspended matter, total phosphorus, orthophosphate and nitrate were evaluated in the laboratory according to the methodology recommended by the Standard Method for analysis. The analysis of the thermal profile showed two different periods such as a circulation in winter with low thermal resistance to circulation (TRC) values, and a stratification in summer with high TRC values. Statistical analyses of relations between this parameter indicated a spatial homogeneity in summer and winter and different between the two periods. Furthermore, correlations in the summer were significant, with negative values for the Total, orthophosphate and dissolved oxygen parameters and positive values for chlorophyll a, and nitrate in the winter