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

2.5. LAKE GUOKALABBALAT Lake Guokalabbalat (watershed of the River Kobbholmselva) is located 30 km to the north of the town of Zapolyarny. The elongated lake is relatively small (area of the lake 0.13 km2), not deep (maximum depth 11 m), and is of glacial origin. The maxi­ mum length is 650 m and maximum width 410 m. The points of maximum depth are located in the central part of the lake. The lake forms part of a lake-river system. According to the landscape type, the watershed belongs to the tun­ dra zone with heights of up to 349 m. Boulder beds occur throughout almost the whole littoral zone. The lake shores are high and covered by grass and shrub vegetation. The water of the lake is col­ ourless both during high water periods and episodes of high precipitation. Physico-geographical characteristics Watershed River Kobbholmselva— the Barents Sea Latitude 69°42.200' Longitude 30°46.752' Height above sea level, m 186.0 Maximum length, km 0.65 Maximum width, km 0.41 Maximum depth, m 11 Area, km 2 0.13 Watershed area, km 2 5.25 Study period 1996-2005 Hydrochemical properties pH 6.34 6.09-6.55 Electrical conductivity, mS/cm 31 27-33 Ca, mg/l 1.32 1.10-1.45 Mg, mg/l 0.68 0.62-0.74 Na, mg/l 3.13 2.72-3.50 K, mg/l 0.28 0.23-0.38 HC03, mg/l M 1.3-2.5 S04, mg/l 4.00 3.81-4.17 Cl, mg/l 5.20 4.37-5.70 Total mineralization, mg/l 16.6 14.4-18.1 Alkalinity, |aeq/l 32 22-41 2.5.1. Hydrochemistry The proximity of the sea has a consider­ able influence on the water quality. The water in the lake is slightly acidified and has a low total mineralization (aver­ age 16.6 mg/l) and alkalinity (average 32 peq/1). During flood periods the pH drops slightly, i.e. oxidation processes do not develop due to the buffering capaci­ ty of the water. The lake has low concen­ trations of base cations and anions, with sodium (average 3.13 mg/l) and chloride (average 5.2 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 precipitation and inflow of humic wa­ ter increase. Elevated concentrations of P and N are important criteria when estimating water eutrophication. The concentrations of and relationships between species of P and N vary according to the season and the dy­ namics is to a greater extent determined by the level of production and, consequently, the trophicity of the water body. The average concentrations of total P and total N during the vegetation period are 5 pg/l and 147 pg/l, respectively. According to the concentrations of mineral nutrients, the lake is classified as ol- igotrophic. The colour values and organic matter (2.6 mg/l) and Fe concentrations (average 15.8 pg/l) are typical of small water bodies in the region. During flood pe- Catalogue ofLakes in the Russian, Finnish and Norwegian BorderArea