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Mývatn - Laxá

Les noms des biens figurent dans la langue dans laquelle les Etats parties les ont soumis.

Islande (Europe et Amérique du nord)
Date de soumission : 18/12/2001
Critères: (vii)(viii)(ix)(x)
Catégorie : Naturel
Soumis par : Menntamalaraduneytid. Ministry of Education, Science and Culture
Coordonnées 65°35' N - 17°00' W
Ref.: 1611

Description

The Mývatn area has unique geological and biological conservation values. The area is part of the Mid-Atlantic Ridge, which stretches as a zone of active volcanism through Iceland from southwest to northeast. The landscape is dominated by post-glacial lava flows extruded by several kinds of volcanoes. An elongate zone of fissures and craters provides visible proof of the fracturing of the earth's crust as the American and Eurasian Plates glide away from each other. Several core areas with volcanic activity (volcanic systems) can be found along this zone. Askja and Krafla have been active recently, providing new information about processes relating to continental drift. Similar areas are rare, and must be sought in Ethiopia, on Hawaii or other small groups of islands, such as the Azores, the Canaries, or the Galapagos Islands.



There is considerable geothermal activity in the area, including bubbling pools of boiling mud, sulphur springs and hot springs. The Earth's crust is extremely thin here and the surface is painted with sulphur and other chemicals. There are also large numbers of pseudo-craters around Mývatn. These form by explosions as hot lava flows into water or over wetland. The best known one is SkUtusta6agigar, which also has special protection status.



Moisture is trapped by the Porous bedrock and moves beneath the surface until itre-appears in a series of springs which supply systems of rivers and lakes. The largest of these is the wetiand area of Mývatn - Laxci. Mývatn (37 km') is situated 278 metres above sea level and contains more than 50 islands. This is one of the largest known assemblages of pseudocraters. The name Mývatn derives from the vast numbers of non-biting midges that live around the lake, sometimes forming clouds or columns.



Some 115 species of birds have so far been recorded in the Mývatn area, and Mývatn and Lax6 have one of the world's richest populations of aquatic birds. At least 28 species of duck have been recorded, the most common being: Tufted duck (Aythya fuligula), Scaup (Aythya marila) and Wigeon (Anas Penelope). Other common ducks are: Barrow's goldeneye (Bucephala islandica), Red-breasted merganser (Mergus serrator), Common scoter (Melanifta nigra) and Mallard (Anas platyrhynchos). In Iceland, 13 of the breeding duck species are extremely rare. Mývatn, along with its immediate surroundings, is the only known breeding area for Barrow's goldeneye in Europe, and the Harlequin duck (Histrionicus histlionicus) has its eastern-most breeding area here. In addition to ducks, 240 breeding pairs of Slavonian grebes (Podiceps auritius) have been recorded, as well as 200 wintering Whooper swans (Cygnus cygnus), Red-necked phalaropes (Phalaropus lobatus), Great Northern divers (Gavia immer) and Red-throated divers (Gavia stellata).



The rich bird life principally owes its presence to the abundant supply of nutrients in the lake, with its enormous primary production and huge quantities of insects and other small creatures. The lake is extremely shallow, so that birds can easily feed off the bottom. The size of the lake, its extensive shallows, many islands, long shoreline, dry climate and varied landscape are other factors of significance for the rich bird life



Considering that this is Iceland, the climate is extremely favourable. The average temperature in January is -0.2 'C and warmest month, July, has an average temperature of 10.2 'C. The area is also one of the sunniest in Iceland and has an annual precipitation of only 400 mm. Since Mývatn is extremely shallow (maximum 4 metres, except for the part where siliceous algae (diatoms) are extracted), sufficient sunlight penetrates to produce an extremely rich bottom vegetation. The fauna in the area leaves a distinctive impression on the vegetation in the area.



Even though Mývatn is a relatively small area, it embodies enormous contrasts. The bare areas of young lava contrast with the older lava, covered with mosses and lichens. Where vegetation development has advanced furthest, vascular plants, bushes and the small, crooked, Icelandic birch trees also occur.



Because the Mývatn area is a farming district, there are numerous buildings, roads and other construction. There is also a factory based on the siliceous alga resources, extracting a 5 1 0 metre thick layer on the bottom of the lake. The factory has permission to operate for a limited period. The natural features in the area are also exploited by the tourist industry that attracts many visitors during the summer.