eutrophication

The paper evaluates the potential impact of internal biogenic pollutants (phosphorus) on the trophic state of the deep, stratified Lake Swiete in Obra, Poland (area 23.3 ha, depth 15.3 m). The amount of phosphorus in interstitial water was analyzed on the basis of spatial studies of 10 cm of surface sediments of bottom sediments. It has been shown that the release of loading accumulated in the water can worsen the trophic state of the lake.

Lake Czarne is an example of a lake that has not been studied until today. The main goal of study is to characterize the hydrochemical properties of Lake Czarne (3.9 ha, 5.1 m) and its trophic condition. The lake waters were characterized by an enough high content of nutrients, up to 0.253 mg P l-1 and 5.10 mg N l-1. The high fertility of the lake was exhibited also by the values of BOD5 reaching 12.4 mg O2 l-1 and low transparency – mean value 0.6 m.