Difference between revisions of "Lake Ladoga" - New World Encyclopedia

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Lake Ladoga, located in the northwestern part of Russia, is the largest lake in all of Europe. The span of the lake is so large that it lies within the borders of two political provinces: the Republic of Karelai and Leningrad Oblast. In total, Lake Ladoga covers an area of 6,700 fresh water square miles, excluding islands. The width of the lake averages 51 miles, while the length is approximately 136 miles. Along with its impressive size, the lake is also remarkably deep, measuring 167 feet on average. The deepest point of the lake is found just to the west of Valaam Island where the lake dips to 754 feet.  
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Lake Ladoga, located in the northwestern part of Russia, is the largest lake in all of Europe. The span of the lake is so large that it lies within the borders of two political provinces: the Republic of Karelai and Leningrad Oblast. In total, Lake Ladoga covers an area of 6,700 fresh water square miles, excluding all 660 of the islands on the lake. The width of the lake averages 51 miles, while the length is approximately 136 miles. Along with its impressive size, the lake is also remarkably deep, measuring 167 feet on average. The deepest point of the lake is found just to the west of Valaam Island where the lake dips to 754 feet.  
  
 
==Geography==
 
==Geography==
 
[[Image:la2-demis-ladoga.png|thumb|200px|left|Map of Lake Ladoga]]
 
[[Image:la2-demis-ladoga.png|thumb|200px|left|Map of Lake Ladoga]]
  
The lake's area is 17,891 [[square kilometre|km²]] (excluding the islands). Its length (north to south) is 219 km, average width is 83 km, average depth is 51 m, maximum depth is about 230 m (in north-western part). Basin area: 276,000 km², volume: 837 km³<ref>Sorokin, Aleksander I. et al. (1996). [http://www.springerlink.com/content/h2q32590g1218861/fulltext.pdf New morphometrical data of Lake Ladoga]. ''[[Hydrobiologia]]'' 322.1-3, 65-67.</ref> (earlier estimated as 908 km³);. There are about 660 islands, with a total area of 435 km². Ladoga's level above the sea is 5 m on average.<ref>Калесник С.В. Ладожское озеро. Л.: Гидрометеоиздат, 1968.</ref> Most of the islands, including the famous [[Valaam]] archipelago, [[Kilpola]] and [[Konevets]], are situated in the north-western part.
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Lake Ladoga was formed as a result of glacier movements approximately 10,000 years ago. According ot most geologists, the lake was originally part of the Blatic Sea that seperated from the main body of water when the Yoldia Sea began to recede around 8,000 years ago. According to this theory, Lake Ladoga and the Baltic Sea continued to be connected by a small strait untile the River NEva was fully formed. In approximately the 12th century A.D. Lake Ladoga and the Baltic Sea were completely seperated becuase the River Neva  was filled with water flowing from Lake Ladoga into the river from the break at Porogi.  
  
Separated from the [[Baltic Sea]] by the [[Karelian Isthmus]], it drains into the [[Gulf of Finland]] via the [[Neva River]].
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The modern form of Lake Ladoga is completely navigable, and serves as an important commercial conduit between the Baltic Sea and the Volga River. In order to facilitate trade along the lake, a canal was built to cut through the southern part of the lake. Ladoga Canal, which connects the Neva to the Svir River, has contributed significantly to commerce by allowing vessels to bypass the southern loop of the lake.  
 
 
The basin of the Ladoga includes about 50,000 lakes and 3,500 rivers longer than 10 km. About 85% of the water income is due to tributaries, 13% is due to [[Precipitation (meteorology)|precipitation]], and 2% is due to underground waters. The most significant tributaries are:
 
* [[Svir River]] from [[Lake Onega]] (south-east, discharge: 790 m³/s);
 
* [[Volkhov River]] from [[Lake Ilmen]] (south, discharge: 580 m³/s);
 
* [[Vuoksi River]] from [[Saimaa|Lake Saimaa]] in [[Finland]] (west, discharge: 540 m³/s).
 
* [[Syas River]] (south, discharge: 53 m³/s).
 
 
 
The Ladoga is navigable, being a part of [[Volga-Baltic Waterway]] connecting the [[Baltic Sea]] with the [[Volga River]]. The [[Ladoga Canal]] bypasses the lake in the southern part, connecting the Neva to the Svir.
 
  
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Lake Ladoga is fed by a series of tributaries and smaller rivers in teh Ladoga basin; approximately 3,500 rivers contribute to the water level in the area. In addition, the Svir River, the Volkhov River, the Vuoksi River, and the Syas River discharge into Lake Ladoga. While the flow of water from these rivers helps to keep the water table of Lake Ladoga at an acceptable level for the acquatic ecosystem, precipiation also plays a part in keeping Lake Ladoga full. The lake recieves approximately 13% of its water from precipitation, and while the percentage appears to be low, it would not be able to maintain a steady water level without annual rainfall.
  
 
[[Image:Lake Ladoga.PNG|left|thumb|120px]][[Image:Jezioro ancylusowe001.jpg|left|thumb|120px|[[Ancylus Lake]]]]
 
[[Image:Lake Ladoga.PNG|left|thumb|120px]][[Image:Jezioro ancylusowe001.jpg|left|thumb|120px|[[Ancylus Lake]]]]
Deglaciation following the [[Weichsel glaciation]] took place in the Lake Ladoga basin between 12,500 and 11,500 [[Before Present|radiocarbon years BP]]. Lake Ladoga was initially part of the [[Baltic Ice Lake]] (70-80 m. above present [[sea-level]]), a historical [[freshwater]] stage of [[Baltic Sea]]. It is possible, though not certain, that Ladoga was isolated from it during [[regression (geology)|regression]] of the subsequent [[Yoldia Sea]] [[brackish]] stage (10,200-9,500 BP). The isolation threshold should be at [[Heinjoki]] to the east of [[Vyborg]], where the [[Baltic Sea]] and Ladoga were connected by a strait or a river outlet at least until the formation of the River Neva, and possibly even much later, until 12th century AD or so.<ref>Ailio, Julius (1915). Die geographische Entwicklung des Ladogasees in postglazialer Zeit. ''Bull. Comm. Géol. Finlande'' 45, 1–159.</ref><ref name="davydova">Davydova, Natalia N. et al. (1996). [http://www.springerlink.com/content/m5423367j2p82762/fulltext.pdf Late- and postglacial history of lakes of the Karelian Isthmus]. ''[[Hydrobiologia]]'' 322.1-3, 199-204.</ref>
 
 
At 9,500 BP, [[Lake Onega]], previously draining into the [[White Sea]], started emptying into Ladoga via the [[River Svir]]. Between 9,500 and 9,100 BP, during the transgression of [[Ancylus Lake]], the next freshwater stage of the Baltic, Ladoga certainly became part of it, even if they hadn't been connected immediately before. During the Ancylus Lake subsequent regression, around 8,800 BP Ladoga became isolated.
 
 
Ladoga slowly [[transgression (geology)|transgressed]] in its southern part due to uplift of the [[Baltic Shield]] in the north. It was hypothesized, but not proven, that waters of the [[Litorina Sea]], the next brackish-water stage of the Baltic, occasionally invaded Ladoga between 7,000 and 5,000 BP. Around 5,000 BP the waters of the [[Saimaa Lake]] penetrated [[Salpausselkä]] and formed a new outlet, [[River Vuoksi]], entering Lake Ladoga in the northwestern corner and raising its level by 1-2 m.<ref>Saarnisto, Matti (1970). The Late Weichselian and Flandrian history of the Saimaa Lake complex. ''Societas Scientiarium Fennicae. Commentationes Physico-Mathematicae'' 37.</ref>
 
 
The River Neva originated when the Ladoga waters at last broke through the threshold at Porogi into the lower portions of [[Izhora River]], then a tributary of the [[Gulf of Finland]], between 4,000 and 2,000 BP. According to some new data, it happened at 3,100 [[Before Present|radiocarbon years BP]] (3,410-3,250 calendar years BP).<ref>Saarnisto, Matti & Tuulikki Grönlund (1996). [http://www.springerlink.com/content/j5148205236j4710/fulltext.pdf Shoreline displacement of Lake Ladoga - new data from Kilpolansaari]. ''[[Hydrobiologia]]'' 322.1-3, 205-215.</ref>
 
  
 
===Wildlife===
 
===Wildlife===

Revision as of 07:41, 19 December 2007

Lake Ladoga
Lake Ladoga - Northern shore
Northern shore
Location Northwestern Russia
Coordinates 61°00′N 31°00′ECoordinates: 61°00′N 31°00′E
Primary sources Svir, Volkhov, Vuoksi
Primary outflows Neva
Catchment area 276,000 km²
Basin countries Russia, Finland
Max length 219 km
Max width 138 km
Surface area 17,700 km²
Average depth 51 m
Max depth 230 m
Water volume 837 km³
Surface elevation 5 m
Islands about 660 (including Valaam)
Settlements see list

Lake Ladoga, located in the northwestern part of Russia, is the largest lake in all of Europe. The span of the lake is so large that it lies within the borders of two political provinces: the Republic of Karelai and Leningrad Oblast. In total, Lake Ladoga covers an area of 6,700 fresh water square miles, excluding all 660 of the islands on the lake. The width of the lake averages 51 miles, while the length is approximately 136 miles. Along with its impressive size, the lake is also remarkably deep, measuring 167 feet on average. The deepest point of the lake is found just to the west of Valaam Island where the lake dips to 754 feet.

Geography

Map of Lake Ladoga

Lake Ladoga was formed as a result of glacier movements approximately 10,000 years ago. According ot most geologists, the lake was originally part of the Blatic Sea that seperated from the main body of water when the Yoldia Sea began to recede around 8,000 years ago. According to this theory, Lake Ladoga and the Baltic Sea continued to be connected by a small strait untile the River NEva was fully formed. In approximately the 12th century C.E. Lake Ladoga and the Baltic Sea were completely seperated becuase the River Neva was filled with water flowing from Lake Ladoga into the river from the break at Porogi.

The modern form of Lake Ladoga is completely navigable, and serves as an important commercial conduit between the Baltic Sea and the Volga River. In order to facilitate trade along the lake, a canal was built to cut through the southern part of the lake. Ladoga Canal, which connects the Neva to the Svir River, has contributed significantly to commerce by allowing vessels to bypass the southern loop of the lake.

Lake Ladoga is fed by a series of tributaries and smaller rivers in teh Ladoga basin; approximately 3,500 rivers contribute to the water level in the area. In addition, the Svir River, the Volkhov River, the Vuoksi River, and the Syas River discharge into Lake Ladoga. While the flow of water from these rivers helps to keep the water table of Lake Ladoga at an acceptable level for the acquatic ecosystem, precipiation also plays a part in keeping Lake Ladoga full. The lake recieves approximately 13% of its water from precipitation, and while the percentage appears to be low, it would not be able to maintain a steady water level without annual rainfall.

Wildlife

Valaam Archipelago

The Ladoga is rich with fish. 48 forms (species and infraspecific taxa) of fish have been encountered in the lake, including roach, carp bream, zander, European perch, ruffe, endemic variety of smelt, two varieties of Coregonus albula (vendace), eight varieties of Coregonus lavaretus, a number of other Salmonidae as well as, albeit rarely, endangered Atlantic sturgeon. Commercial fishing was once a major industry but has been hurt by overfishing. After the war, between 1945–1954, the total annual catch increased and reached a maximum of 4,900 tonnes. However, unbalanced fishery led to the drastic decrease of catch in 1955–1963, sometimes to 1,600 tonnes per year. Trawling has been forbidden in Lake Ladoga since 1956 and some other restrictions were imposed. The situation gradually recovered, and in 1971-1990 the catch ranged between 4,900 and 6,900 tonnes per year, about the same level as the total catch in 1938.[1] Fish farms and recreational fishing are developing. [1]

It has its own endemic Ringed Seal subspecies known as the Ladoga Seal.

Since the beginning of the 1960s Ladoga has become considerably eutrophicated.[2]

Nizhnesvirsky Natural Reserve is situated along the shore of Lake Ladoga immediately to the north of the mouth of the River Svir.

History

Konevets Island

In the Middle Ages, the lake formed a vital part of the Trade Route from the Varangians to the Greeks, with the Norse emporium at Staraya Ladoga defending the mouth of the Volkhov since the 8th century. In the course of the Swedish-Novgorodian Wars, the area was disputed between the Novgorod Republic and Sweden. In the early 14th century, the fortresses of Korela (Kexholm) and Oreshek (Nöteborg) were established along the banks of the lake.

The ancient Valaam Monastery was founded on the island of Valaam, the largest in Lake Ladoga, abandoned between 1611–1715, magnificently restored in the 18th century, and evacuated to Finland during the Winter War in 1940. In 1989 the monastic activities in the Valaam were resumed. Other historic cloisters in the vicinity are the Konevets Monastery, which sits on the Konevets island, and the Alexander-Svirsky Monastery, which preserves fine samples of medieval Muscovite architecture.

During the Ingrian War, a fraction of the Ladoga coast was occupied by Sweden. In 1617, by the Treaty of Stolbovo, the northern and western coast was ceded by Russia to Sweden. In 1721, after the Great Northern War, it was restituted to Russia by the Treaty of Nystad. Later, in 1812–1940 the lake was shared between Finland and Russia. According to the conditions of the 1920 Tartu Peace Treaty militarization of the lake was severely restricted. However, both Soviet Russia and Finland had flotillas in Ladoga. After the Winter War (1939-1940) according to the Moscow Peace Treaty, Ladoga, previously shared with Finland, became an internal basin of the Soviet Union.

During the Continuation War (1941-1944) not only Finnish and Soviet, but also German and Italian (see Regia_Marina#Lake_Ladoga) vessels operated there. Under these circumstances, during much of the Siege of Leningrad (1941–1944), Lake Ladoga provided the only access to the besieged city. Supplies were transported into Leningrad with trucks on winter roads over the ice, the "Road of Life", and by boat in the summer. After the World War II, Finland lost the Karelia region to the USSR, and all Finnish citizens were evacuated from the ceded territory. Ladoga became an internal Soviet basin again. The nortern shore, Ladoga Karelia with the town of Sortavala, is now part of the Republic of Karelia. The western shore, Karelian Isthmus, became part of Leningrad Oblast.


Notes

  1. Kudersky, Leonid K. et al. (1996). Fishery of Lake Ladoga — past, present and future. Hydrobiologia 322.1-3, 57-64.
  2. Holopainen, Anna-Liisa et al. (1996) The trophic state of Lake Ladoga as indicated by late summer phytoplankton. Hydrobiologia 322.1-3, 9-16.

References
ISBN links support NWE through referral fees

  • Butler, Sue. 1998. Via Leeds to Lake Ladoga. Bradford: Redbeck Press. ISBN 9780946980642
  • Viljanen, Markku. 2004. Sustainable use, management and monitoring of fish resources in Lake Ladoga. Karjalan tutkimuslaitoksen raportteja, n:o 4/2004. [Joensuu]: Joensuun yliopisto. ISBN 9789524585019


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