Lappkärret is a small lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 at Norra Djurgården in north-eastern central Stockholm

Stockholm

Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

, Sweden

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

. It is one of six lakes in Djurgården, the others being: Lillsjön

Lillsjön, Djurgården

Lillsjön is a small, former lake at Norra Djurgården, a rural area in north-eastern central Stockholm, Sweden, forming part of the national city park Ekoparken...

, Uggleviken

Uggleviken

Uggleviken is a former bay and lake at Norra Djurgården, a rural area in north-eastern central Stockholm, Sweden, forming part of the national city park Ekoparken....

, Isbladskärret

Isbladskärret

Isbladskärret is a small lake on Djurgården, an island in central Stockholm, Sweden. The lake is much appreciated among bird-watchers, and, being part of the National park in central Stockholm, Ekoparken, also carefully monitored by several organizations, including the World Wide Fund for Nature...

, Laduviken, and Spegeldammen

Spegeldammen

Spegeldammen 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 Lappkärret....

.

Through its location in the national city park

National park

A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

 Ekoparken

Ekoparken

The Royal National City Park is the world's first National City Park, established in 1995 in the municipalities of Stockholm, Solna and Lidingö in Sweden.1/ km²2/ Population per km²- Pictures :Some places in "The Eco Park"....

, it is considered as a lake of great recreational value, especially popular among ornithologists

Ornithology

Ornithology is a branch of zoology that concerns the study of birds. Several aspects of ornithology differ from related disciplines, due partly to the high visibility and the aesthetic appeal of birds...

 and frequently used in classes at the University of Stockholm located nearby. As the name implies, it used to be a marsh

Marsh

In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

 until construction works for the student apartments at Lappkärrsberget

Lappkärrsberget

Lappkärrsberget is a residential area in Norra Djurgården in central-eastern Stockholm, Sweden. Located just north of the Stockholm University, it is known for the approximately 2,000 student flats located there. It is known amongst students as Lappis ....

 punctured a subsoil spring in the 1960s. Today, the lake empties into the strait Lilla Värtan

Lilla Värtan

Lilla Värtan or simply Värtan is a strait in Stockholm, Sweden. Separating mainland Stockholm from the island and municipality Lidingö, it stretches from Blockhusudden in the south to Stora Värtan in the north...

 through a culvert and forms part of a proposed nature reserve

Nature reserve

A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...

 at Norra Djurgården.

Catchment area

Most of the catchment area is composed of open fields and areas of spruce

Spruce

A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...

 and deciduous forest, with a single trafficked road passing west of the lake. Next to a group of nearby allotment-gardens

Allotment (gardening)

An allotment garden, often called simply an allotment, is a plot of land made available for individual, non-professional gardening. Such plots are formed by subdividing a piece of land into a few or up to several hundreds of land parcels that are assigned to individuals or families...

 is a 4-H

4-H

4-H in the United States is a youth organization administered by the National Institute of Food and Agriculture of the United States Department of Agriculture , with the mission of "engaging youth to reach their fullest potential while advancing the field of youth development." The name represents...

 farmyard with horses and sheep.

Environmental influence

Most of the inflow is believed to come from subsoil water with some contribution from stormwater

Stormwater

Stormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...

 and snow-melting. Local land usage produces small amounts of nutrients and no conduits guides surface water to the lake. The lake is alkali

Alkali

In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

 and saliferous with high levels of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

, phosphorus

Phosphorus

Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

, and phosphate

Phosphate

A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...

, but low levels of inorganic nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

. Notwithstanding various levels of chlorophyll

Chlorophyll

Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...

, water transparency exceeds the depth of the lake and pH

PH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 is reported as constant.

Flora and fauna

In the mid 1980s, isolated occurrences of Rigid Hornwort

Ceratophyllum

Ceratophyllum is a cosmopolitan genus of flowering plants, commonly found in ponds, marshes, and quiet streams in tropical and in temperate regions...

 had established in the lake, and, by the mid 1990s, abundant quantities of other aquatic plant

Aquatic plant

Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...

s such as Ivy Duckweed

Lemna

Lemna is a genus of free-floating aquatic plants from the duckweed family. These rapidly-growing plants have found uses as a model system for studies in community ecology, basic plant biology, in ecotoxicology, in production of biopharmaceuticals, and as a source of animal feeds for agriculture...

 and the liverwort

Marchantiophyta

The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....

 Riccia Fluitans

Riccia fluitans

Riccia fluitans, whose common name is crystalwort, is an aquatic floating plant of the liverwort genus Riccia which is popular among aquarists as a retreat for young fry and is used in live-bearing tanks. It can be found floating in ponds, and often forms thick mats on and under the water...

, 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 larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e and non-biting midges

Chironomidae

Chironomidae are a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae...

. Within ten years, however, the fauna had evolved considerably, probably due to the rich vegetation, to include Oligochaeta

Oligochaeta

Oligochaeta is a subclass of animals in the biological phylum Annelida, which is made up of many types of aquatic and terrestrial worms, and this includes all of the various earthworms...

, Gasteropods, and dragonfly

Odonata

Odonata is an order of insects, encompassing dragonflies and damselflies . The word dragonfly is also sometimes used to refer to all Odonata, but the back-formation odonate is a more correct English name for the group as a whole...

 larvae and today also the dragonfly species Aeshna osiliensis

Aeshna

Aeshna is the scientific name of a genus of dragonflies from the family Aeshnidae. They are also known as hawker dragonflies, or, in North America, as mosaic darners.-Description:These are relatively large dragonflies...

, Common Winter Damselfly

Sympecma fusca

The Common Winter Damselfly, Sympecma fusca, is a damselfly that is found in much of central and southern Europe. It does not have the bright blue or red colouration that is more usual for damselflies so it is often overlooked. It is one of only two species of European dragonflies that overwinter...

, and several others.

The only fish in the lake is Crucian Carp

Crucian carp

The crucian carp is a member of the family Cyprinidae, which includes many other fish, such as the common carp, or the smaller minnows. They inhabit lakes, ponds, and slow-moving rivers throughout Europe and Asia. The crucian is a medium-sized cyprinid, which rarely exceeds a weight of over 3.3...

, 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 Gull

Black-headed Gull

The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident...

s together with Slavonian Grebe

Slavonian Grebe

The Horned Grebe or Slavonian Grebe, Podiceps auritus, is a member of the grebe family of water birds. The Slavonian Grebe is an excellent swimmer and diver, and pursues its fish prey underwater...

, Mallard

Mallard

The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....

, Little Grebe

Little Grebe

The Little Grebe , also known as Dabchick, member of the grebe family of water birds. At 23 to 29 cm in length it is the smallest European member of its family. It is commonly found in open bodies of water across most of its range.-Description:The Little Grebe is a small water bird with a pointed...

, and Gadwall

Gadwall

The Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...

. 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 amphibian

Amphibian

Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

s can be seen by the lake, including Common Frog

Common Frog

The Common Frog, Rana temporaria also known as the European Common Frog or European Common Brown Frog is found throughout much of Europe as far north as well north of the Arctic Circle in Scandinavia and as far east as the Urals, except for most of Iberia, southern Italy, and the southern Balkans...

, Common Toad

Common Toad

The common toad or European toad is an amphibian widespread throughout Europe, with the exception of Iceland, Ireland and some Mediterranean islands...

, Moor Frog

Moor Frog

The Moor Frog is a slim, reddish-brown, semi-aquatic amphibian native to Europe and Asia. It is a member of the family Ranidae, or "true frogs".-Taxonomy:...

, and Smooth Newt

Smooth Newt

The Smooth Newt, also known as the Common Newt, Lissotriton vulgaris is the most common newt species of the Lissotriton genus of amphibians. L...

.

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

Universitetet

Universitetet, , is a Metro station in the Frescati area, close to Stockholm University , and the Museum of Natural History. It was opened on 12 January 1975....

and bus 40 stops not far away.