Laduviken ( sv, Barn Bay) is a

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

Norra Djurgården NORRA or Norra may refer to: * Nordic Regional Airlines, a Finnish airline operating on behalf of, and formerly majority-owned by, Finnair * National Off-Road Racing Association, a desert off-road racing association * Norra (village) Norra (germa ...

, a semi-rural area in north-eastern

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

, forming part of the

Royal National City Park The Royal National City Park ( sv, Kungliga nationalstadsparken) is a national city park, established by the Riksdag in 1995, and located in the municipalities of Stockholm, Solna and Lidingö in Sweden. 1/ km²2/ Population per km² Gallery ...

. It is one of six lakes in

Djurgården Djurgården ( or ) or, more officially, ''Kungliga Djurgården'' (), is an island in central Stockholm, Sweden. Djurgården is home to historical buildings and monuments, museums, galleries, the amusement park Gröna Lund, the open-air museum ...

, the others being: Lillsjön, Uggleviken,

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 Royal National City Park, also carefully monitored by several organizations, including t ...

, Lappkärret, and

Spegeldammen Spegeldammen ( sv, (the) Mirror Pond) is a small lake in 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. ...

Catchment area

Most of the catchment area is composed of open grassland with scattered oaks and other

hardwood Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...

. West of the lake, the buildings of the

Stockholm University Stockholm University ( sv, Stockholms universitet) is a public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, so ...

take up some 20 per cent of the surface and a few roads, a traffic route, the suburban railway

Roslagsbanan Roslagsbanan is a narrow gauge commuter railway system in Roslagen, Stockholm County, Sweden. Its combined route length is and there are 38 stations. It is built to the Swedish three foot () gauge. The Storstockholms Lokaltrafik (SL) classifies ...

, and the subterranean metro passes through the area. East of the lake are some minor one-family houses and commercial buildings. The terrain north of the lake is flat while the southern shore is steep and, as the area west of the lake is drained by a ditch dug through a filled-up wetland, most of the catchment area is located there and most of the inflow comes from an ooze and oil separator treating water from human-made structures. A tiny river guides the outflow east to the bay Husarviken which is part of the strait

Lilla Värtan Lilla Värtan ( sv, Smaller 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, and is ...

. In the late 1970s, the lake was deepened by dredging to prevent it from becoming choked-up during the 21st century, and a system of canals was then created in the western end of the lake. As part of a national park, the lake is considered as of great recreational value.Vattenprogram, p 1.3-1.4

Environmental influence

Most of the

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

reaching the lake are most likely derived from the university, while

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

contribution is derived from surrounding landscape and equal shares of

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

input stems from all surrounding areas and structures. Generally the lake is considered as in good health with low levels of most metals and

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

s, even though presence of

hydrogen sulphide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

has been recorded relatively frequently, levels of copper in top sediments did increase during the 1990s, and analysis's of subsoil water in 1997 showed signs of environmental contamination.

Flora and fauna

Presence of

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...

is low in August with exceptional

blue green algae Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blue ...

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

, and

golden algae The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, ''Prymnesium parvum'', which ...

. Occurrence of

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

is more varied with several species of

rotifer The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John H ...

cladocera The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more ...

ns, and

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s. Among the

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

s in the lake fennel pondweed is notable as it normally only occurs in sea bays. Other aquatic plants and

nymphoides ''Nymphoides'', or floatingheart, is a genus of aquatic flowering plants in the family Menyanthaceae. The genus name refers to their resemblance to the water lily '' Nymphaea''. ''Nymphoides'' are aquatic plants with submerged roots and floating ...

include

rigid hornwort ''Ceratophyllum demersum'', commonly known as hornwort, rigid hornwort, coontail, or coon's tail, is a species of ''Ceratophyllum''. It is a submerged, free-floating aquatic plant, with a cosmopolitan distribution, native to all continents except ...

, broad-leaved pondweed,

perfoliate pondweed ''Potamogeton perfoliatus'' (claspingleaf pondweed, perfoliate pondweed, redhead grass) is a perennial aquatic plant in the family Potamogetonaceae occurring in both standing and flowing freshwater habitats. It is widely distributed globally, oc ...

, water-starwort, ''

Nymphaea alba ''Nymphaea alba'', the white waterlily, European white water lily or white nenuphar , is an aquatic flowering plant in the family Nymphaeaceae. It is native to North Africa, temperate Asia, Europe and tropical Asia (Jammu and Kashmir). Descript ...

'', ''

Lemna ''Lemna'' is a genus of free-floating aquatic plants referred to by the common name "Lemnoideae, duckweed". They are morphologically divergent members of the arum family Araceae. These rapidly growing plants have found uses as a Model organism, m ...

'', and '' Chara tomentosa'' (for which the lake is, together with

Kyrksjön Kyrksjön ( sv, Church Lake) is a small lake in Bromma, a western suburb in Stockholm, Sweden. Named after its vicinity to the old Bromma Church, the lake was made part of the nature reserve Kyrksjölöten in 1997. Three other lakes are located ...

, the only locale in Stockholm).Vattenprogram, p 1.4-1.7 The sparse fauna before the dredging of the lake, after 1995 evolved into a pretty considerable variety of species typical for shallow lakes rich in nutrients. Two species of freshwater snails, ''

Bithynia leachii ''Bithynia leachii'' is species of small freshwater snail with an operculum, an aquatic prosobranch gastropod mollusk in the family Bithyniidae. Distribution It is a Palearctic species found in North Africa and Europe to East Siberia. * Cze ...

'' and '' Gyraulus crista'', were earlier considered as endangered. Noteworthy is also the population of several freshwater mussels,

duck mussel Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfam ...

and swan mussel, and '' Hippeutis complanatus'', the latter two declining. A species of

Oligochaeta Oligochaeta () is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadrile earthworm ...

new in Sweden has been reported in the lake just like did the rare

hairy dragonfly ''Brachytron'' is a monotypic genus of European dragonfly of the family Aeshnidae containing the hairy dragonfly (''Brachytron pratense''), also known as the hairy hawker or spring hawker. Description The hairy dragonfly is named for its hairy ...

. An inventory of dragonfly larvae in 2000 unveiled several other species (mostly

red-eyed damselfly ''Erythromma najas'', the red-eyed damselfly, is a member of the Coenagrionidae family of damselfly, damselflies. Appearance The species is a small damselfly, long, predominantly black with iridescent blue markings. The male resembles blue-tai ...

but also

common blue damselfly ''Enallagma cyathigerum'' (common blue damselfly, common bluet, or northern bluet) is a species found mainly between latitudes 40°N and 72°N; It is widely distributed in the Palearctic, and the Nearctic species '' Enallagma annexum'' was at on ...

azure damselfly The azure damselfly (''Coenagrion puella'') is a species of damselfly found in most of Europe. It is notable for its distinctive black and blue colouring. They are commonly found around ponds and lakesides during the summer. Morphology Adults ...

, variable damselfly, and northern damselfly (''Coenagrion hastulatum''). Fish population reflects the shortage of oxygen with an absence of

carp bream The common bream, freshwater bream, bream, bronze bream, carp bream or sweaty bream (''Abramis brama''), is a European species of freshwater fish in the family Cyprinidae. It is now considered to be the only species in the genus ''Abramis''. ...

and silver bream and an abundance of

perch Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Percif ...

roach Roach may refer to: Animals * Cockroach, various insect species of the order Blattodea * Common roach (''Rutilus rutilus''), a fresh and brackish water fish of the family Cyprinidae ** ''Rutilus'' or roaches, a genus of fishes * California roach ...

, and

crucian carp The crucian carp (''Carassius carassius'') is a medium-sized member of the common carp family Cyprinidae. It occurs widely in northern European regions. Its name derives from the Low German ''karusse'' or ''karutze'', possibly from Medieval Lat ...

dating back to before the dredging. The outlet forms a threshold for migrating species.

Mallard The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...

and

great crested grebe The great crested grebe (''Podiceps cristatus'') is a member of the grebe family of water birds noted for its elaborate mating display. Taxonomy The great crested grebe was formally described by the Swedish naturalist Carl Linnaeus in 1758 in t ...

are breeding in the lake, just like are occasionally

common moorhen The common moorhen (''Gallinula chloropus''), also known as the waterhen or swamp chicken, is a bird species in the rail family (Rallidae). It is distributed across many parts of the Old World. The common moorhen lives around well-vegetated mars ...

and

Canada goose The Canada goose (''Branta canadensis''), or Canadian goose, is a large wild goose with a black head and neck, white cheeks, white under its chin, and a brown body. It is native to the arctic and temperate regions of North America, and it is o ...

(introduced in Sweden in the 1930s).

Marsh warbler The marsh warbler (''Acrocephalus palustris'') is an Old World warbler currently classified in the family Acrocephalidae. It breeds in temperate Europe and the western Palearctic and winters mainly in southeast Africa. It is notable for incorpora ...

and

gray heron The grey heron (''Ardea cinerea'') is a long-legged wading bird of the heron family, Ardeidae, native throughout temperate Europe and Asia and also parts of Africa. It is resident in much of its range, but some populations from the more northern ...

are often seen among the reed. Even though reed have been cleared to attract

wader 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...

s, as a locale for birs, the lake hasn't met expectations much due to neglected attention of the canals and islands. There are three species of protected

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

s in the lake:

common frog The common frog or grass frog (''Rana temporaria''), also known as the European common frog, European common brown frog, European grass frog, European Holarctic true frog, European pond frog or European brown frog, is a semi-aquatic amphibian o ...

common toad The common toad, European toad, or in Anglophone parts of Europe, simply the toad (''Bufo bufo'', from Latin ''bufo'' "toad"), is a frog found throughout most of Europe (with the exception of Ireland, Iceland, and some Mediterranean islands), in ...

, and smooth newt. The deers once abundant in the area have been superseded by

roe deer The roe deer (''Capreolus capreolus''), also known as the roe, western roe deer, or European roe, is a species of deer. The male of the species is sometimes referred to as a roebuck. The roe is a small deer, reddish and grey-brown, and well-adapt ...

s.SNF

Visiting

The lake and the national city park are easily accessible by bus, metro, bicycle, or by foot. Nearest metro station is Universitetet. Each year the relay race Convinistafetten is held around Laduviken.

Notes

References

* *

External links

* {{cite web , url=http://www.stockholmvatten.se/Stockholmvatten/Vattnets-vag/Sjovard/Sjoar-och-vattendrag/Laduviken/ , title=Laduviken , publisher=Stockholm Vatten , accessdate=2007-05-23 , language=Swedish , archiveurl=https://web.archive.org/web/20070927014255/http://www.stockholmvatten.se/Stockholmvatten/Vattnets-vag/Sjovard/Sjoar-och-vattendrag/Laduviken/ , archivedate=2007-09-27 , url-status=dead Geography of Stockholm Lakes of Stockholm County Lakes in Djurgården