Lac Pavin
| Lac Pavin | ||
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| Geographical location | France | |
| Data | ||
| Coordinates | 45 ° 29 '45 " N , 2 ° 53' 17" E | |
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| Altitude above sea level | 1197 m | |
| surface | 44 ha | |
| Maximum depth | 92 m | |
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particularities |
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The Lac Pavin is a volcanic maar lake in the French Massif Central on the south-eastern edge of the Monts Dore . At around 6000 years old, the maar is one of the youngest volcanic objects in the Auvergne.
location and size
The lake is 1197 m high in the Auvergne in the Puy-de-Dôme department between the towns of Besse-en-Chandesse and the ski resort of Super Besse . It is about 44 hectares and up to 92 m deep.
Meromictic lake
The Lac Pavin is unique in France in its water circulation: it runs meromictically . The mixture of the water covers only the first 60 meters in the semi-annual and annual cycle. The water at the bottom of the lake, between 60 and 92 meters, is held there and saturated with gases such as carbon dioxide , methane and hydrogen sulphide , which are created by the breakdown of organic material and give the water a bad smell. The gas content makes it necessary to monitor the lake, as an increase can lead to a sudden and dangerous discharge. According to scientists, however, the water has not reached saturation and is in a less dangerous stable state. However, earth movements or seismics can disturb this equilibrium and trigger a sudden degassing through the release of the gas contained in the underlying sediment.
The lake is home to the char , which has adapted to deep waters (30 to 70 meters). Methane-forming bacteria also live in Lac Pavin, as do other species that feed on this gas.
Legend
According to a legend, every stone thrown into it triggers a storm.
Web links
Individual evidence
- ↑ Lac Pavin in the Global Volcanism Program of the Smithsonian Institution (English)
- ↑ a b Le lac Pavin: un lac méromictique (invité Michel Meybeck) dans l'émission Planète terre de France Culture du 22 September 2010.
- ↑ Lehours AC, Carrias JF, Amblard C, Sime-Ngando T, Fonty G, “Les bactéries du lac Pavin”, Pour la Science , January 2010, pp. 30-35.
- ↑ Michelin: The Green Guide - Auvergne Berry, 2009 edition, page 93