Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

Fig. 40. Vertical distribution of the concentrations of Pb and Hg (цд/д, dry weight) in the sediment core of Lake Elientja. 2.2.3. Hydrobiology studies No direct hydrobiological investigations have been carried out in this lake. 2.3. LAKE GARDSJOEN Lake Gardsjoen (watershed of the River Jacobselv) is located 31 km to the north of the town of Zapolyarny. The oval­ shaped lake is relatively small (area of the lake 0.75 km2) and not deep (maxi­ mum depth 16 m), and is of glacial ori­ gin. The maximum length is 1.65 km and maximum width 0.7 km. The points of maximum depth are located in the central part of the lake. According to the landscape type, the watershed area belongs to the tundra zone, with heights up to 282 m. The lake shores are high and covered by shrubs an colourless both during high water periods Physico-geographical charact Watershed River Jacobselv— the Barents Sea Latitude 69°42.460' Longitude 30°51.068' Height above sea level, m 82.0 Maximum length, km 1.65 Maximum width, km 0.7 Maximum depth, m 10 Area, km 2 0.75 Watershed area, km 2 10.5 Study period 2003-2005 birch woodland. The water of the lake is id episodes of high precipitation. 2.3.1. Hydrochemistry The proximity of the sea has considerable influence on the water quality of the lake. The pH in the water is neutral and the water has a low total mineralization (average 20.1 mg/l) and alkalinity (average 60 |ieq/l). During flood periods the pH drops slightly, i.e. oxidation processes do not develop due to the buffering capacity of the water. The lake has low concentrations of base cations and anions, with sodium (average 3.61 mg/l) and chloride (average 5.82 mg/l) predominating. The annual chemical cycle of the lake is characterized by a slight reduction in the oxidizability and pH of the water during flood periods when the amount of precipita­ tion and inflow of humic water increase. 78 Catalogue of Lakes in the Russian, Finnish and Norwegian BorderArea