Magelungen is one of the biggest 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,...

s in 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....

, located between the municipalities of Stockholm and Huddinge

Huddinge Municipality

Huddinge Municipality is a municipality in Stockholm County in east central Sweden. Its seat is located in Huddinge, which is a part of Stockholm urban area.The municipality is the second most populated in Stockholm County....

. It is considered as of great recreational value and is popular for bathing, yachting, and fishing in summers, and tour skating

Tour skating

Tour skating is a sport and recreational form oflong distance ice skating on natural ice.The Nordic style of tour skating is popular in the Nordic countries,especially Sweden, but increasingly in...

 in winters. It is bordering two nature reserves: Fagersjöskogen/Farstanäset and Rågsved Open-Air Area.

Catchment area

Less than half of the catchment area is composed of forest and open grasslands. Some 10 per cent is wetlands and parks, and the remaining area used for one-family houses and blocks of flats. Two bridges crosses the lake and several major roads are passing through the catchment area, as do the above ground tracks of the metro and suburban railway. South of the lake is a larger continuous forest, a golfe course, and an open-air centre. On the northern side are, besides the nature reserve, area used for riding and 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...

.

The primary catchment area is relatively small and composed of three ditches — Magelungsdiket

Magelungsdiket

Magelungsdiket is one of three inflows of Lake Magelungen in southern Stockholm, Sweden. It empties into the lake from north together with Kräppladiket while Djupån reaches the southern end of the lake....

, Kräppladiket

Kräppladiket

Kräppladiket is one of the three inflow rivers of Lake Magelungen in southern Stockholm, Sweden. It empties into the lake in its northern end together with Magelungsdiket while Djupån joins the lake on its southern end....

, and Djupån — together contributing about 3 million cubic metres annually. 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...

 is brought to the lake via a great number of pipes together bringing about 10 million cubic metre. The remaining catchment area brings less than 1 million cubic metres annually.

Environmental influence

Most of the 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...

 discharged into the lake, totalling 1,800 kg/year, is brought from the lake Ågestasjön

Ågestasjön

- External links :...

 (~1,000 kg) through the Norrån

Norrån

Norrån is a river in Södermanland, Sweden.-External links:*...

 river, while the primary catchment area brings some 500 kg. Of the 25 tons of 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...

 brought annually to the lake, about 18 tons comes from Norrån and some 6 tons from the primary catchment area. The deepest south-eastern part of the lake suffers from oxygen deficiency and hydrogen sulphide which causes high levels of phosphorus. Most of the zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

 and copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 comes from roofs, while high levels of metals have been reported in stormwater from a local industrial area.

Flora and fauna

In the south-eastern part of the lake phytoplankton

Phytoplankton

Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...

s are dominated by various species of cyanobacterias, some of which are nitrogen-binding and potentially poisonous, and exceptionally other nutrient-demanding algae and dinoflagellates. Zooplankton

Zooplankton

Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...

 are only found in small quantities. Variations in quantity appears between the southern and northern parts of the lake, with more an abundant presence of green algae

Green algae

The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...

 in the northern end where dinoflagellates are substituted also by diatom

Diatom

Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...

s. Striking when it comes to 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 is the abundance of Spiked Water-milfoil

Myriophyllum spicatum

Myriophyllum spicatum is a species of Myriophyllum native to Europe, Asia, and north Africa. It is a submerged aquatic plant, and grows in still or slow-moving water.-Description:...

 and Rigid Hornswort

Ceratophyllum

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

 in the north-western part of the lake. An inventory in 1998 also documented Chara globularis

Charales

Charales is an order of pondweeds, freshwater algae in the division Charophyta. They are green plants believed to be the closest relatives of the green land plants. Linnaeus established the genus Chara in 1753.-Description:...

, Common waterweed

American waterweed

Elodea canadensis is a perennial aquatic plant, or submergent macrophyte, native to most of North America. It was first recorded from the British Isles in about 1836.-Distribution:...

, White Water-lily

Nymphaea alba

Nymphaea alba, also known as the European White Waterlily, White Lotus, or Nenuphar, is an aquatic flowering plant of the family Nymphaeaceae....

, Yellow water-lily

Nuphar lutea

Nuphar lutea is an aquatic plant of the family Nymphaeaceae, native to temperate regions of Europe, northwest Africa, and western Asia.-Growth:...

, Branched Bur-reed

Sparganium

Sparganium is a genus of flowering plants, containing about 20 species in temperate regions of both the Northern and Southern Hemispheres. It was previously placed alone in the family Sparganiaceae...

, Flowering rush, and Stratiotes aloides

Stratiotes

Stratiotes is a genus of submerged aquatic plant commonly known as water soldiers. A characteristic of the genus is the habit of the plants rising to the surface at flowering time.-Description:...

.

An inventory of the fauna in 1997 documented some 55 species, which considered a relatively high diversity. Most prevalent was freshwater Gastropods

Gastropoda

The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...

, Caddisflies

Trichoptera

The caddisflies are an order, Trichoptera, of insects with approximately 12,000 described species. Also called sedge-flies or rail-flies, they are small moth-like insects having two pairs of hairy membranous wings...

, and Leech

Leech

Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...

es, and Beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s. Common fishes are Perch

Perch

Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. The perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning spotted, and the...

, Abramis bjoerkna, Roach

Rutilus

Rutilus is a genus of fishes in the family Cyprinidae, commonly called roaches. Locally, the name "roach" without any further qualifiers is also used for particular species, particularly the Common Roach Rutilus (Latin for "shining, red, golden, auburn") is a genus of fishes in the family...

, and Zander

Zander

Zander is a species of fish. The scientific name is Sander lucioperca , and it is closely allied to perch. Zander are often called pike-perch as they resemble the pike with their elongated body and head, and the perch with their spiny dorsal fin. Zander are not, as is commonly believed, a pike and...

; but Burbot

Burbot

The burbot is the only gadiform fish inhabiting freshwaters. It is also known as mariah, the lawyer, and eelpout. It is closely related to the marine common ling and the cusk...

, European smelt

European smelt

The Smelt or European smelt is a species of fish in the Osmeridae family.- Shape and appearance :The body of the European smelt is typically 15 to 18 cm long, slender and slightly flattened on either side. Larger fish may reach 30 cm in length. Smelts have a slightly translucent body...

, and eel

Eel

Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

 have also been reported. Zander, Grass carp

Grass carp

The grass carp is a herbivorous, freshwater fish species of family Cyprinidae, and the only species of the genus Ctenopharyngodon. It is cultivated in China for food, but was introduced in Europe and the United States for aquatic weed control...

, and Trout

Trout

Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

 have been introduced. Angling is thus popular in the lake. Crayfish plague

Crayfish plague

Crayfish plague, Aphanomyces astaci, is a water mould that infects crayfish, most notably the European Astacus which dies within a few weeks of being infected...

 struck the lake in 1978 but Signal crayfish

Signal crayfish

The signal crayfish, Pacifastacus leniusculus, is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the Scandinavian Astacus astacus fisheries, which were being damaged by crayfish plague, but the imports turned out to be a carrier of that disease...

 was reintroduced in 1984.

An number of bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s breed along the north-western shore, including Eurasian Coot

Eurasian Coot

The Eurasian Coot, Fulica atra, also known as Coot, is a member of the rail and crake bird family, the Rallidae. The Australian subspecies is known as the Australian Coot.-Distribution:...

, Common Moorhen

Common Moorhen

The Common Moorhen is a bird in the Rallidae family with an almost worldwide distribution. The North and South American Committees of the AOU and the IOC have voted on or before July 2011 to split the American forms into a new species Common Gallinule, however, no other committee has voted to...

, 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....

, and Great Crested Grebe

Great Crested Grebe

The Great Crested Grebe is a member of the grebe family of water birds.- Description :The Great Crested Grebe is long with a wingspan. It is an excellent swimmer and diver, and pursues its fish prey underwater. The adults are unmistakable in summer with head and neck decorations...

. Lesser Spotted Woodpecker

Lesser Spotted Woodpecker

The Lesser Spotted Woodpecker is a member of the woodpecker family Picidae. It is assigned to the genus Dendrocopos ....

 have been reported in the surrounding forest and the lake is the home of a rare couple of Marsh harrier

Marsh harrier

The marsh harriers are birds of prey of the harrier subfamily. They are medium-sized raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds...

. Except for 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...

, Common Gull

Common Gull

The Common Gull or Mew Gull Larus canus is a medium-sized gull which breeds in northern Asia, northern Europe and northwestern North America. It migrates further south in winter...

, Herring Gull, and Common Tern

Common Tern

The Common Tern is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding in temperate and sub-Arctic regions of Europe, Asia and east and central North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. It is sometimes...

, also Osprey

Osprey

The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...

, Heron

Ardea (genus)

Ardea is a genus of herons. Linnaeus named this genus as the Great Herons, referring to the generally large size of these birds, typically 80–100 cm or more in length....

, Canada Goose

Canada Goose

The Canada Goose is a wild goose belonging to the genus Branta, which is native to arctic and temperate regions of North America, having a black head and neck, white patches on the face, and a brownish-gray body....

, Mute Swan

Mute Swan

The Mute Swan is a species of swan, and thus a member of the duck, goose and swan family Anatidae. It is native to much of Europe and Asia, and the far north of Africa. It is also an introduced species in North America, Australasia and southern Africa. The name 'mute' derives from it being less...

, and Greylag Goose

Greylag Goose

The Greylag Goose , Anser anser, is a bird with a wide range in the Old World. It is the type species of the genus Anser....

 have been sighted. Breeding species include Great Crested Grebe, Common Teal

Common Teal

The Eurasian Teal or Common Teal is a common and widespread duck which breeds in temperate Eurasia and migrates south in winter. The Eurasian Teal is often called simply the Teal due to being the only one of these small dabbling ducks in much of its range...

, Common Snipe

Common Snipe

The Common Snipe is a small, stocky wader native to the Old World. The breeding habitat is marshes, bogs, tundra and wet meadows throughout northern Europe and northern Asia...

, and Reed Bunting

Reed Bunting

The Reed Bunting, Emberiza schoeniclus, is a passerine bird in the bunting family Emberizidae, a group now separated by most modern authors from the finches, Fringillidae....

. Only occasionally seen are Garganey

Garganey

The Garganey is a small dabbling duck. It breeds in much of Europe and western Asia, but is strictly migratory, with the entire population moving to southern Africa, India Santragachi and Australasia in winter, where large flocks can occur. This species was first described by Linnaeus in 1758...

, Common Kingfisher, Osprey, 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...

 among others.

Frog

Frog

Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

 fry

Fry

-Food and cooking:* Frying, the act of cooking food in oil or fat** Pan frying, frying food in a flat pan** Stir frying, frying food in a wok and stirring it while it cooks* Full breakfast, a traditional cooked meal, also called a fry-up or Ulster fry...

 was reported in 2001 near the inflow of the lake, an indication 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 are resettling the area. Several species of bat

Bat

Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s have been sighted around the lake.