Prestvannet
Conservation area
The lake Prestvannet, rarely also called Prestvatn, is an approximately eight -acre artificial lake on the Norwegian island Tromsøya in the province (county ) Troms. Since 1970, the Prestvannet with its immediate surroundings a conservation area, which also serves the protection of animals.
- 2.1 Water Quality
- 2.2 Flora 2.2.1 Water plants
- 2.2.2 marsh plants
- 2.3.1 birds
- 2.3.2 fish
Geography
General
The Prestvannet lies entirely in the city of Tromsø. It is located in the southern part of the island Tromsøya at 96 meters above sea level ( Moh ). The lake is shallow and usually no deeper than four meters. Only in the center greater depths are reached. The entire conservation area has a size of approximately 18 hectares. The lake itself is 7.88 acres in size and goes south into a large-scale wetland. Other small wetlands are located in the northwest, northeast and the eastern shore. To the wetland, a birch forest connects.
Formation
As part of the drinking water supply of the city of Tromsø in 1867, the lake was dammed on a moor landscape with smaller ponds. However, he served only as a temporary reservoir of drinking water, because the water quality turned out to be too bad. With the construction of the new water plant in Slettaelva in 1921, the use has been discontinued.
Islands
The lake is Torfinseln that were likely to be flooded by the rapid flooding of the moorland. In 1870, many Torfinseln were counted and also Sparre Schneider reported in 1889 by a series of floating islands of peat. Furthermore, it may solve part of the Torfkante. They will get back to grow into floating islands later with the reason. The number varies from year to year. Bacteria decompose organic material in the lake. This creates gases which require the buoyancy process of Torfinseln. This depends on the water temperature.
Ecology
Water quality
The water is rich in nutrients, with large amounts of humus. This caused the color of the water is not very transparent. With a water test in August 2005, the phosphorus content was very high.
Flora
There are basically two different types of plants that grow in the Prestvannet: aquatic plants and wetland plants. The birch forest belongs to the genus of downy birch.
Aquatic plants
It is home to a total of only three different types of aquatic plants in the lake. They are among the most common in Norway. The most numerous is Berchtold dwarf pondweed ( Potamogeton berchtoldii ), which situates itself in depths of one to one and a half meters. It occurs both in nutrient-rich than in nutrient-poor waters. In addition, it tolerates the low light conditions in the lake and grows well on the flooded peat soil. In the north and east of the lake of the mare's tail ( Hippuris vulgaris ) is native. He is also found on dry mud banks. In the deeper areas of the lake are found sporadically Floating pondweed ( Potamogeton natans ).
Marsh plants
Sedges ( Carex aquatilis and Carex rostrata ) is growing around the lake and is even found on the Torfinseln. Many of the marsh plants grow up to two meters deep here. The pond horsetail ( Equisetum fluviatile ) grows in the northeast of the lake, forming many floating islands that look like mainland. Other marsh plants that grow around the lake, marsh blood eye are ( Potentilla palustris ) and fever clover ( Menyanthes trifoliata ).
Fauna
By Torfinseln find many birds protected breeding areas on the lake. The orders most often expressed are the Anseriformes, Charadriiformes and Passeriformes dar. The table below is a selection of species represented is listed. Some of the species are observed every year and others appear irregular. The order of birds of prey is one of the rare visitors to the lake. In addition, herons and feral pigeons are sighted on the lake. A special feature is the breeding place of the red-throated diver, as the birds are very shy and usually avoid being close to people. Tromsø is one of the few places where the bird breeds in the vicinity of people. Because species richness is the welfare of the nature reserve of great interest.
Pisces
Due to the low oxygen content of only two different types of fish could be located. The three-spined stickleback does not need much oxygen, but because of the climate, it is quite possible that the lake freezes completely. This dies every winter a part of the stock. The crucian carp which was also suspended in the lake can switch a shortage of oxygen from aerobic to anaerobic metabolism. Through an anaerobic metabolism produces lactic acid, which is fermented to ethanol ( lactic acid fermentation). This alcohol acts in the blood by its lower freezing point than " antifreeze " so that the crucian carp can survive complete freezing through the lake. Excess alcohol can be excreted through the gills.
Leisure and Tourism
The lake is now a recreational area for the city of Tromsø. Bridges, bridges and benches were installed, from which you can watch the birds. Information boards clarify the visitor on. The adjacent forest area is a popular hiking area in Tromsø.