8. The Seasonal Variation of Temperature, pH and Dissolved Oxygen Concentration

In order to have a complete picture of the limno-ecological conditions, 17 measuring and sampling points were chosen. The points chosen covered the whole of the bathymetric and morphological spectrum of the lake. The measurements were carried out on the surface and from meter to meter as far as the bottom and they were repeated in every season; spring, summer, autumn and winter. The pH of the water is found to be slightly alkaline throughout the year with a range of 7.5–8.0 (Fig. 8.5). Very rarely, in certain conditions, the pH value falls within the circum-neutral category. The existence of dissolved oxygen is essential for the water table. Even given this, the Red Lake is not the object of extraordinary biological diversity, which follows from the fact that its existence is relatively recent. All these parameters are important because, at their junction, they define the vegetal and animal life conditions that the Red Lake has to offer. The geographic location of the lakes in Romania, in distinct landform units (mountains, hills, and plains, littoral) creates different environments for the manifestation of trophicity. According to the value of the nutrients, the greatest parts of the lakes (wetlands) are situated in the mesotrophic, meso-eutrophic, eutrophic, eutro-hypertrophic and hypertrophic categories.