Ancient lake

Under a Langzeitsee (English ancient lake ) refers to a lake which continuously performs at least one million years water, because usually freshwater lakes and reservoirs are far younger. Numerous post-glacial lakes (eg Lake Constance ) are not 20,000 years old. The short existence of such state waters located on the regular entry of sediment by the inflows. This silted up the lake within a few millennia. Most of the reason for the long life of long-term lakes located in a geological formation. Here, for example, is counteracted by the plate tectonics of the silting.

Biological significance of long-term lakes

In evolutionary biology, long-term lakes serve as " laboratories " of nature. Similar to the famous Galapagos Islands such lakes form as it were islands of water in an ocean of land. Due to the long life can often develop species that are native only in the respective lake in such isolated habitats: the so-called endemic species. Evolutionary biologists investigate the characteristics and conditions that led to the emergence of new species within a manageable compared to the mainland or ocean ecosystem of the lake. In Lake Tanganyika in Central Africa, the radiation of cichlids is investigated, for example. In Europe, Lake Ohrid, a center of evolutionary research is on there endemic molluscs.

Selected long-term lakes

• Lake Baikal (Russia)
• Lake Biwa (Japan)
• Lake Ohrid ( South East Europe)
• Lake Tanganyika (East Africa)
• Lake Malawi (East Africa)
• Lake Titicaca (South America)

• Still waters