Lappkärret

Infobox_lake
lake_name = Lappkärret
image_lake = Lappkarret_2007.jpg
caption_lake = (November 2007)
image_bathymetry =
caption_bathymetry =
coords = coord|59|22|6.48|N|18|4|6.90|E|region:SE_type:waterbody_scale:10000|display=inline,title
type =
inflow = Subsoil water
outflow = Lilla Värtan
catchment = 17 ha
basin_countries = Sweden
length =
width =
area = 2.3 ha
depth = 0.7 m
max-depth = 1.1 m
volume = 16,000 m³
residence_time = 5 months
shore =
elevation =
islands =
cities = Norra Djurgården
reference = Vattenprogram, p 2.1]

Lappkärret ( _sv. Laplander Marsh) is a small lake at Norra Djurgården in north-eastern central Stockholm, Sweden. It is one of six lakes in Djurgården, the others being: Lillsjön, Uggleviken, Isbladskärret, Laduviken, and Spegeldammen.

Through its location in the national city park Ekoparken, it is considered as a lake of great recreational value, especially popular among ornithologists and frequently used in classes at the University of Stockholm located nearby. As the name implies, it used to be a marsh until construction works for the student apartments at Lappkärrsberget punctured a subsoil spring in the 1960s. Today, the lake empties into the strait Lilla Värtan through a culvert and forms part of a proposed nature reserve at Norra Djurgården.

Catchment area

Most of the catchment area is composed of open fields and areas of spruce and deciduous forest, with a single trafficked road passing west of the lake. Next to a group of nearby allotment-gardens is a 4-H farmyard with horses and sheep.Vattenprogram, p 2.3]

Environmental influence

Most of the inflow is believed to come from subsoil water with some contribution from stormwater and snow-melting. Local land usage produces small amounts of nutrients and no conduits guides surface water to the lake. The lake is alkali and saliferous with high levels of oxygen, phosphorus, and phosphate, but low levels of inorganic nitrogen. Notwithstanding various levels of chlorophyll, water transparency exceeds the depth of the lake and pH is reported as constant.

Flora and fauna

In the mid 1980s, isolated occurrences of Rigid Hornwort had established in the lake, and, by the mid 1990s, abundant quantities of other aquatic plants such as Ivy Duckweed and the liverwort Riccia Fluitans, were reported along open edges of the lake. During that decade, submarine vegetation covered the entire lake bed which greatly cleared up the lake. In the mid 1980s, the only fauna reported was sparse occurrences of larvae and non-biting midges. Within ten years, however, the fauna had evolved considerably, probably due to the rich vegetation, to include Oligochaeta, Gasteropods, and dragonfly larvae and today also the dragonfly species Aeshna osiliensis, Common Winter Damselfly, and several others.Vattenprogram, p 2.3-2.6]

The only fish in the lake is Crucian Carp, probably introduced in the early 1980s. Attempts have been made to reduce the population with various results. In the mid 1970 a colony of Black-headed Gulls together with Slavonian Grebe, Mallard, Little Grebe, and Gadwall. The Black-headed Gull is a key species, offering protection to other species, and has now abandoned the lake which is, however, still considered as of great importance to bird life with several species still breeding there. Several protected species of amphibians can be seen by the lake, including Common Frog, Common Toad, Moor Frog, and Smooth Newt.

Visiting

Both the lake and the surrounding national park is easily accessible by metro, bus, bicycle, or by foot. The nearest metro station is Universitetet and bus 40 stops not far away.

See also

* Geography of Stockholm
* Lakes in Sweden

Notes

References

* cite web
url = http://www.stockholmvatten.se/Stockholmvatten/commondata/infomaterial/Sjo/01laduv.pdf
title = Vattenprogram för Stockholm 2000 - Lappkärret
publisher = Stockholm vatten
accessdate = 2007-05-25
language = Swedish
format=PDF
* cite web
url = http://portal.miljomiljarden.se/wf_miljomiljarden/home/ext_projects_view.asp?projectid=132
title = B144 Lappkärret - nytt utlopp ("New outlet")
publisher = City of Stockholm
accessdate = 2007-05-25
language = Swedish

External links

* cite web
url = http://www.stockholmvatten.se/Stockholmvatten/Vattnets-vag/Sjovard/Sjoar-och-vattendrag/Lappkarret/
title = Lappkärret
publisher = Stockholm vatten
accessdate = 2007-05-25
language = Swedish