Summary:

In article the influence of loads of biogenic substances (total nitrogen and total phosphorus) inflowing with water of Wisła river on eutrophication process of water Goczałkowice reservoir was presented. The research was conducted in years 2004-2006 and 2010-2011, in vegetative seasons. The loading total phosphorus of Goczałkowice reservoir was calculated and the acceptable load and dangerous load of total phosphorus (according to Vollenveider 1976) have both been calculated. The enumerated value of loading of total phosphorus load was compared to the value of acceptable loads and dangerous loads. Moreover, biomass of phytoplankton (given in wet mass) was calculated and a species composition of phytoplankton was determined. The analyses declared that the loads of total phosphorus, which were contributed with water of Wisła river were lesser in years 2010-2011 (averagely 0,147 g P•m-2•year-1) than loads, which flowed in years 2004-2006
(0,681 g P•m-2•year-1). The first exchanged loads had exceeded only values of acceptable loads. It can indicate to the improvement of the conditions in the catchment area. In spite of the lesser inflow of the loads, it was ascertained that water of the reservoir still points out eutrophic character. The high concentrations of total phosphorus (averagely 0,05 mg P•dm-3 (2004-2006) and averagely 0,062 mg P•dm-3 (2010-2011)), total nitrogen (averagely 1,26 mg N•dm-3 (2004-2006) and averagely 1,38 mg N•dm-3 (2010-2011)), chlorophyll a (averagely 26,83 μg•dm-3 (2004-2006) and 33,36 μg•dm-3 (2011)) and the high values of phytoplankton biomass (averagely 7,39 mg•dm-3 (2004-2006)) in the reservoir, also typically for eutrophic water a species of phytoplankton (i.a. Microcystis viridis (A. Br. in Rabenh.) Lemm., Coelastrum sp., Euglena viridis (Carter) confirm the eutrophic status of the reservoir.