The role of lakes in inflow of water and biogenic substances in the polish part of the southern Baltic Sea

Abstract

Polish rivers, which make up 20% of the Baltic Sea's catchment area, transport a load of nitrogen and phosphorus compounds into the sea. Theoretically, this load should be strongly correlated with the amount of water flowing in those rivers. However, this is not the case, especially in terms of the phosphorus compounds, since most of them come from point source pollution. The outflow load is also significantly influenced by nonpoint source pollution from farmland, which is very difficult to quantify. About 50% of nitrogen and 30% of phosphorus appear to come from nonpoint source pollution. It is important to realize that the load from nonpoint source pollution also includes the load of phosphorus and nitrogen transformed by lakes. Only recently, however, has this issue been mentioned in the specialist literature. In Polish studies on lake balance this remains a marginal issue. A limited number of observations indicate that lakes are capable of both limiting and increasing the load (mainly from the bottom sediments). This article presents some data on this issue which suggest that the roles of lakes in the transformation of the load of biogenic substances may be significant, but diverse.

The Functioning of a Water Body Within a Fluvio-Lacustrine System as an Effect of Excessive Nitrogen Loading—The Case of Lake Symsar and its Drainage Area (Northeastern Poland)

“…Nitrogen is one of the main nutrients responsible for the eutrophication process. One-third of the average inflow of water to the Baltic Sea originates from Poland [4], with approximately 25% nitrogen and 40% phosphorus reaching the sea via the fluvial route. In the area of Northern Poland, the route of almost every river runs through lakes [4].…”

“…The lakes of Northeastern Poland enable the limitation of the transport of pollutants via rivers to the Baltic Sea. By converting the load, they can reduce or increase it, depending on the volume of loading [4]. According to Hillbricht-Ilkowska and Kostrzewska-Szlakowska [14], fluvio-lacustrine systems are perceived as systems of alternate lake and river sections connected to one another by the continuous exchange of components.…”

Total Alkaline Phosphatase Activity in Bottom Sediments of Rusalka Lake in the City of Szczecin

“…Szczecin is situated in North-Western Poland, in the western part of West Pomeranian Voivodeship in the Polish-German border [24].…”

“…This is the reservoir formed by the medieval Mill River House Osówka [24]. Lake morphometric data: Length -670 m, width -70 m, the height of the mirror -16 m above sea level, type of lake: prohibitive [24] Map 1. Location of the measuring point in Rusalka lake in Szczecin 53°26'44″N 14°32'05″E…”

Total Alkaline Phosphatase Activity in Water of Rusalka Lake in the City of Szczecin

“…This is the reservoir formed by the medieval Mill River House Osówka [24]. Lake morphometric data: Length -670 m, width -70 m, the height of the mirror -16 m above sea level, type of lake: prohibitive [24]. Samples of littoral and sublittoral water were taken with a Ruttner sampler with a capacity of 2 dm 3 .…”