Ladoga lake

Lake Ladoga

Area: 18 135 km2
Maximum depth: 230 m

Lake Ladoga is a lake in Karelia (North and East coast) and Leningrad region (the Western, southern and South-Eastern shore), the largest freshwater lake in Europe. Belongs to the basin of the Baltic sea Atlantic ocean. The lake area without the Islands is from 17.6 thousand km2 (including the Islands 18.1 thousand km2); the volume of water - 30 km3; the length from North to South is 219 km, the maximum width is 138 km Depth non-uniformly: in the North part of it ranges from 70 to 230 m, in South - from 20 to 70 m On the shores of the Ladoga lake is located the town of Priozersk, Novaya Ladoga, Shlisselburg, Leningrad region, Sortavala, Pitkyaranta, Lahdenpohja in Karelia. In the lake Ladoga fall 35 rivers, and originates only one - Neva. In the southern half of the lake - three large Bay: Svirskaya, Volkhov and Schliesselburg lips.

Climate.

The climate over lake Ladoga is moderate, transitional from temperate continental to temperate Maritime. This type of climate is explained by the geographical position and atmospheric circulation typical of the Leningrad region. This is due to the relatively small number of arriving at the earth's surface and in the atmosphere of the sun's heat. Because of the small amount of solar heat, moisture evaporates slowly. For a year is on average 62 Sunny days. Therefore, throughout most of the year is dominated by days, with cloudy and overcast weather, the scattered light. The length of the day varies from 5 hours 51 minutes on the winter solstice to 18 hours 50 minutes in the summer solstice. Above the lake there are the so-called "white nights", the upcoming may 25-26, when the sun is below the horizon for not more than 9 degrees, and the twilight practically coincide with the morning. The white nights end on July 16-17. In total length of the white nights over 50 days. The amplitude of monthly sums of direct solar radiation on a horizontal surface under clear skies from 25 MJ/m2 in December to 686 MJ/m2 in June. Clouds decreases in average per year, the arrival of total solar radiation by 21 %, and direct solar radiation by 60 %. Average annual total radiation 3156 MJ/m2. The number of sunshine hours - in 1628 year.

A noticeable influence on the climatic conditions renders the lake itself. It is characterized by smoothing the extreme values of the climatic characteristics, resulting in the continental air masses passing over the surface of the lake, take the nature of the Maritime air masses. The average temperature in the area of Ladoga lake +3.2 °C. the Average temperature of the coldest month (February) ?8.8 °C, and the warmest (July) is +16.3 °C. the Average annual rainfall is about 475 mm, the Lowest monthly precipitation in February - March (24 mm), the highest - in September (58 mm). During the year a greater part of lake Ladoga is dominated by Western and South-Western winds. Average monthly wind speed in the open part of the lake and on the majority of Islands from October to January - February 6-9 m/s, in the remaining months 4-7 m/S. On the coast of the average monthly wind speed varies from 3 to 5 m/S. the Wind are observed seldom. In October, on lake Ladoga, there are often storm winds with speeds of over 20 m/s, the maximum wind speed reaches 34 m/S. the Breezes are observed on the coast in the summer on a calm Sunny days and clear nights. Lake breeze begins around 9 am and lasts until 20 PM, his rate of 2-6 m/s; it spreads on 9-15 km inland. Fogs occur most often in the spring, late summer and autumn.

Shore, bottom topography and hydrography of the lake.

The lake area without the Islands is from 17.6 thousand km2 (including the Islands 18.1 thousand km2); the length from North to South is 219 km, the maximum width is 138 km of the Volume of water lake - 30 km3. This is 12 times larger than annually flows into him rivers and taken by the Neva river. Seasonal fluctuations of water level in the lake is small due to the significant area of the water surface of the reservoir and because of the relatively small annual variation in the number of flowing water. The last is caused by the presence of large lakes within the catchment area of lake Ladoga and the availability of hydropower on all major tributaries that together provides a relatively uniform supply of water throughout the year. Lake shoreline more than 1000 km. North shore, from Priozersk to the West to Pitkaranta in the East, mostly high, rocky, highly rugged, form numerous Peninsula and inlets (fjords and skerries), and small Islands separated by the Straits. The southern shore is low, poorly cut, flooded due to neotectonic submeridional distortion of the lake. The coast here is replete shoals, rocky reefs and banks. In the southern half of the lake - three large Bay: Svirskaya, Volkhov and Schliesselburg lips. East coast Malaysian, it gets two gulfs - Lunkulansaari, Axoloti, separated from the lake one of the largest Islands of Ladoga - Mantsinsaari. Here there are the wide, sandy beaches. The Western coast has less indented. It is overgrown with dense mixed forest and brush, damaged close to the water's edge, along which the scattering of boulders. Ridge of stones often depart from the capes far into the lake, forming dangerous underwater rocks.

For the relief of the bottom of Ladoga lake is characterized by the depth increases from South to North. Depth non-uniformly: in the North part of it ranges from 70 to 230 m, in South - from 20 to 70 m Average depth of the lake - 50 m, the largest - 233 m (to the North of the island of Valaam). The seabed of the Northern part uneven crossed with troughs, and the southern part of the more peaceful and is more smoothness. Lake Ladoga ranks eighth among the deepest lakes in Russia. Transparency at the Western coast of lake Ladoga 2-2,5 m on the East coast of 1-2 m in the mouth areas of 0.3-0.9 m, and the lake is increased to 4.5 M. the Lowest transparency was observed in the Volkhov Bay (0.5-1 m), and the highest - West of Valaam Islands (summer 8-9, in the winter of more than 10 m). On the lake there are constant unrest. During strong storms water in it "boils", and the waves are almost entirely covered with foam. The water regime is characterized negative and positive events (water level fluctuations 50-70 cm annually, up to 3 m), seiche (up to 3-4 m), height of waves at storm up to 6 m The lake freezes in December (coastal area) and February (Central part), opened in April - may. The Central part is covered with solid ice only in very severe winters. Because of the long and severe winter cooling water in the lake and the summer is very cold; it warms only in a thin upper layer and the coastal strip. The temperature regime differs in the Central deep part of the lake and the coast. The temperature of surface water in August to 24 °C in the South, 18-20 °C in the centre, near the bottom, about 4 °C, in the winter under ice 0-2 °C. The water is fresh and clean (except the sites polluted by industrial effluents), minerals and salts dissolved in very small quantities. Water belongs to the hydrocarbonate class (low content of salts of calcium and magnesium, slightly more Nickel, aluminium).

Pool and Islands.

In the lake Ladoga fall 35 rivers. The biggest river which runs into it, is the Svir river, which gives it water from lake Onega. Also in the lake receives water through the river Vuoksi from lake Saimaa, and through the Volkhov river - from lake Ilmen. It also fall into the Morje river, Aloha, Stormy, Cokoliniame, soskuanjoki river, Iijoki, Aurajoki, Tohmajoki, Janisjoki, Susquenita, Uksunyoki, Tolemaico, Miinalanjoki, Vidlitsa, Tuloksa, Olonka, Abanka, Veronica, Syas, Lava, Brandy, Naziya and others. The Neva river is the only river that flows from lake Ladoga. The catchment area is 258 600 km2. Approximately 85 % (3820 mm) positive part of water balance gives the flow of river water, 13 % (610 mm) atmospheric deposition and 2 % (90 mm) - groundwater inflow. About 92 % (4170 mm) expenditure side of the balance goes to the flow of the Neva river, 8 % (350 mm) - on the water surface evaporation. The water level in the lake is not constant. His hesitation is well marked by more than a light strip on the surface of leaving the rocks into the water. On Ladoga lake is about 660 Islands (the area more than 1 ha) total area 435 km2. About 500 of them are concentrated in the Northern part of the lake, in the so-called Northern district, and also in structure of Valaam (approx 50 Islands, including the island Byebye), West of the archipelago, and the island group of Mantsinsaari (approx 40 Islands). The biggest Islands are Riekkalansaari (55.3 km2), Mantsinsaari (39.4 km2), Kilpola (32.1 km2), the Island (30.3 km2) and Valaam (27.8 km). The most famous in the Ladoga lake Valaam Islands - an archipelago of some 50 Islands area of 36 km2, due to the location on the main island of the archipelago of the Valaam monastery. Also known island of Konevets, on which the monastery is located.

Flora and fauna.

The Northern and Eastern coast of Ladoga lake belong to the subzone of middle taiga and South and West to the subzone of the South taiga. For characteristic of the middle taiga spruce forests-such as bilberry without undergrowth, with a closed stand and continuous cover of the brilliant green moss. In the subzone of the South taiga's dominated by dark coniferous breeds with undergrowth, where sometimes there are lime, maple, elm, you receive the herb layer with the participation of Asherah grasses and mosses are less developed than in the middle taiga subzone. The most typical type of forest spruce-kiselychnyk. Island lake rocky, with high, up to 60-70 m, sometimes steep banks covered with forest, sometimes almost glabrous or with sparse vegetation. Southern and South-Western shore of the lake, over 150 km overgrown with reed and cattail. Here are the shelter and nesting of waterfowl. On the Islands many nests of gulls, they grow blueberries, cranberries, and the larger is the mushrooms. In Ladoga there are 120 species of higher aquatic plants. Along the shores of the Islands and the mainland stretch reed-beds with a width of 5-10 m In a deeply embedded in the dry bays are experiencing diverse groups of macrophytes. Width of a strip of vegetation in these areas reaches 70-100 meters. There is almost no vegetation along the Eastern and Western shores of the lake. In the open waters of the lake vegetation is weakly developed. This is because the depth, the water temperature, small quantity of salts dissolved nutrients, coarse sediment, as well as frequent and strong emotion. Therefore, the most diverse vegetation is found in the North of the Northern area of lake Ladoga. In the lake common 154 species of diatoms, 126 species of green and 76 species of blue-green algae. In-depth Ladoga waters contains only 60-70 thousand microorganisms in cm3, and in the surface layer - from 180 to 300 thousand, that speaks about the weak capacity of the lake to cleanse itself.

In the Ladoga lake was revealed 378 species of zooplankton. More than half of the species accounted for rotifers. The fourth part of the total number of species is the simplest, and 23 percent fall together on cladocerans and copepods. The most common in the lake zooplankton species are daphnids and Cyclops. A large group of aquatic invertebrates inhabit the bottom of the lake. In Ladoga they found 385 species (mostly various crustaceans). The first place in the structure of benthofauna belongs to insect larvae, which accounted for more than half of all species of benthic animals 202 species. Further there are worms (66 species), water mites, or hydracarina, molluscs, crustaceans and other. The lake is rich in freshwater fish for spawning go upstream. In lake Ladoga live 53 species and fish species: Ladoga slingshot, salmon, trout, char, whitefish, vendace, smelt, bream, Sirte, blue bream, silver bream, redfin, ASP, catfish, perch, roach, perch, pike, burbot, and others. Human impact on the water reduces numbers of valuable fish - salmon, trout, brook trout, lake whitefish river and others, and the Atlantic sturgeon and Volkhov whitefish listed in the Red book of Russia. The most productive areas refers shallow southern part of the lake with depths up to 15-20 m, where is concentrated the main fish, and the least productive - North skerry area. From the Gulf of Finland on the Neva river for spawning in the Volkhov river and other rivers, passes through lake sturgeon. Along the southern and South-Eastern shore of lake Ladoga usual perch. Resides in the lake salmon, which in the autumn goes to the river, where the spawns. In lake Ladoga and bred the Volkhov whitefish, Siberian sturgeon and other fish. In the Ladoga area meets regularly 256 bird species belonging to 17 orders. On transit migration in spring and autumn it is marked more than 50 species of birds. Travel links Ladoga cover the area from Iceland to India and from South Africa to the New Earth. The most attractive to birds areas is South of the region. Here on migration meet grebes, swans, geese, ducks, waders, gulls, terns, cranes and rails, and the nesting of ducks, tufted ducks, common pochard, gulls, terns, large and medium-Curlew, black-tailed Godwit, common Redshank, Golden shorebirds and other waders, gray crane, white-tailed eagle, osprey, the red-footed Falcon, eagle owl, great grey owl, short-eared owls and other birds. Northern skerries are nesting red-necked grebe, large and medium mergansers, gulls (including sea gulls and lesser black-backed gulls, terns (including Arctic terns), shorebirds and many other species on migration are observed clusters of Arctic ducks and waders. In the Ladoga lake is home to the only pinnipeds, the Ladoga ringed seal. The number of seals in the lake is estimated at 4000-5000 goals (data of 2000). Species listed in the Red book.

 


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