Status of water objects in Republic of Karelia
2007
Lozovik, P.A. (ed.) | Kulikova, T.P. (ed.) | Martynova, N.N. (ed.)
In 1998-2006 integrated hydrochemical and hydrobiological observations were carried out at over 70 monitoring sites for describing pollution and nutrient status of the water objects: Lake Onego (LO), northern Lake Ladoga and their tributaries, Vygozersko-Ondskoye impoundment reservoir, Kostomuksha area waters (Kenti and Kontokki river systems), lakes Suojarvi and Iso-Pyhajarvi. In situ observations, biotesting and chemical control of wastewaters were implemented. In addition, the chemical composition of precipitation and chemical deposition was investigated throughout Karelia. The book emphasizes to LO : it belongs to the meso-polyhumic (Hum=45, Fe=0.82 mg/l) moderately alkaline circumneutral (Alk = 21 mg HCO3/I, pH = 7.1) eutrophic (Ptot — 33 ug/l) water class. Human-induced transformations are the heaviest in small watercourses. Chemical parameters in the Petrozavodsk Bay range widely in the winter season: (PO - 7—41 mg 0/1, Ptot-14-37 ug/1, 02 - 74-90%). In the ice-free period, water masses are more evenly distributed over the bay (PO - 9-15 mg O/l, P,0, - 15-31 ug/1, 02 - 87-95%). The hydrometeorological conditions are responsible for the intensity of water exchange between the bay and the lake. The tendency for increase in concentrations of organic matter, N, P and Fe in bottom sediments first recorded in the early 1980s still holds. In areas exposed to human impact (especially in the Kondopoga and Petrozavodsk bays), sediments are noted for high organic matter content with high С:N (16-44) and С:P (80-100) ratios and very high oxygen consumption. Bottom sediments in the bays are contaminated with hydrocarbons, phenols, lignosulphonates. Phytoplankton on LO demonstrates a rise in the proportions of chlorococcal, cryptophytic algae and cyanobacteria-indicators of eutrophic waters Golden algae lose in significance, which usually happens when the nutrient status of a waterbody changes. The structure of zooplankton comprises a considerable proportion of rotifers, including Kellicottia longispina, Asplanchna priodonta (sometimes up to 90%).
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