**3. Results**

#### *3.1. Polluted versus Pristine Site: Water Temperature, Visibility and TOC*

Visibility was on average 3.8 times lower at the polluted site (6.5 ± 1.7 m; mean ± SD throughout text unless stated otherwise) when compared with pristine site (25 ± 1.1 m; Figure 3). The water temperatures that were recorded at the polluted site ranged between 19–26 ◦C (Figure 3). During summer periods, especially in August, as a result of intensive fish feeding activities, Secchi disk water depth dropped to 4–6 m at the polluted site (Figure 3). TOC levels at the

polluted site (280 ± 0.07 <sup>μ</sup>mol L<sup>−</sup>1) were 2.4 times higher than the TOC levels at the pristine site (110 ± 0.01 <sup>μ</sup>mol L<sup>−</sup>1).

**Figure 3.** Water temperature (in ◦C, black squares with dottled line) and Secchi water depth (in m, black and white circles with continuous line) measurements for the pristine and polluted site over a 31-month time frame (June 2011–December 2013).
