Spatial and seasonal dynamics of water physical–chemical parameters in rivers and lakes of an Argentinian Patagonia basin

The Senguer River basin, located in central Argentinian Patagonia, has its headwater in the Andean Range and ends in extra-Andean Patagonian plains. Within this region, the water bodies may be affected by their localization and the climatic and hydrological seasonality. At the lower basin, there are higher temperatures, evaporation and human impact, and lower precipitation and land cover. In addition, rainfall and runoff are higher during the winter and spring, while temperatures, wind intensity, and evaporation are higher during the summer and autumn. However, the characteristics and dynamics of the water bodies of this basin are not well known. This work aims to study the physical–chemical characteristics of the rivers and lakes of the Senguer River basin to establish their spatial and seasonal variations. During 1 year, seasonally, it was measured the concentration of total, organic and inorganic suspended sediments (TSS, OSS, ISS, respectively), total dissolved solids (TDS), pH, dissolved oxygen (DO), water temperature, chlorophyll a (Chl a), total phosphorus and Secchi disk depth. At the lower basin, water bodies present higher TSS, TDS, Chl a, and turbidity. The seasonal variability has a high impact on TSS (higher on the spring) and water temperature (higher on summer); however, the effect on the other variables is lower relative to the importance of the localization. The two extremes of the basin, Fontana Lake (Fo; located in the Andean zone) and Musters Lake (Mu; located extra-Andean plains), differed in TSS (Fo = 0.4 ± 0.3 mg L⁻¹; Mu = 4.3 ± 2.8 mg L⁻¹), TDS (Fo = 14 ± 1 mg L⁻¹; Mu = 278 ± 9 mg L⁻¹), water transparency (Fo = 11.8 ± 1.2 m; Mu = 3.1 ± 2.4 mg L⁻¹), and Chl a (Fo = 0.42 ± 0.17 μg L⁻¹; Mu = 3.93 ± 2.23 μg L⁻¹). Our results allow a better understanding of the differences between the Andean and extra-Andean water bodies in Patagonia.