Laduviken
Encyclopedia
Laduviken is a lake
in Norra Djurgården, a rural area in north-eastern Stockholm
, Sweden
, forming part of the national city park
Ekoparken
(Nationalstadsparken). It is one of six lakes in Djurgården, the others being: Lillsjön
, Uggleviken
, Isbladskärret
, Lappkärret
, and Spegeldammen
.
Most of the catchment area is composed of open grassland with scattered oaks and other hardwood
. West of the lake, the buildings of the Stockholm University
take up some 20 per cent of the surface and a few roads, a traffic route, the suburban railway Roslagsbanan
, 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
. 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.
reaching the lake are most likely derived from the university, while nitrogen
contribution is derived from surrounding landscape and equal shares of copper
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
s, even though presence of hydrogen sulphide 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.
is low in August with exceptional Blue Green Algae, Green Algae
, and Golden Algae
. Occurrence of zooplankton
is more varied with several species of Rotifer
s, Cladocera
ns, and Copepod
s. Among the aquatic plant
s in the lake Fennel Pondweed
is notable as it normally only occurs in sea bays. Other aquatic plants and nymphoides
include Rigid Hornwort
, Broad-leaved Pondweed
, Perfoliate Pondweed
, Water-Starwort
, Nymphaea Alba
, Lemna
, and Chara Tomentosa
(for which the lake is, together with Kyrksjön
, the only locale in Stockholm).
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
and Gyraulus crista
, were earlier considered as endangered. Noteworthy is also the population of several freshwater mussels, Duck mussel
and Swan mussel
, and Hippeutis complanatus
, the latter two declining. A species of Oligochaeta
new in Sweden has been reported in the lake just like did the rare Hairy Dragonfly
. An inventory of dragonfly larvae in 2000 unveiled several other species (mostly Red-eyed Damselfly
but also Common Blue Damselfly
, Azure Damselfly
, Variable Damselfly
, and Northern Damselfly (Coenagrion hastulatum). Fish population reflects the shortage of oxygen with an absence of Carp bream
and Silver bream and an abundance of Perch
, Roach
, and Crucian carp
dating back to before the dredging. The outlet forms a threshold for migrating species.
Mallard
and Great Crested Grebe
are breeding in the lake, just like are occasionally Common Moorhen
and Canada Goose
(introduced in Sweden in the 1930s). Marsh Warbler
and Gray Heron are often seen among the reed. Even though reed have been cleared to attract wader
s, as a locale for birs, the lake hasn't meat expectations much due to neglected attention of the canals and islands. There are three species of protected frog
s in the lake: Common Frog
, Common Toad
, and Smooth Newt
. The deers once abundant in the area have been superseded by Roe Deer
s.
.
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,...
in Norra Djurgården, a rural area in north-eastern 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....
, forming part of 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"....
(Nationalstadsparken). 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...
, Lappkärret
Lappkärret
Lappkärret 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....
, 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....
.
Catchment area
Hardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...
. West of the lake, the buildings of the Stockholm University
Stockholm University
Stockholm University is a state university in Stockholm, Sweden. It has over 28,000 students at four faculties, making it one of the largest universities in Scandinavia. The institution is also frequently regarded as one of the top 100 universities in the world...
take up some 20 per cent of the surface and a few roads, a traffic route, the suburban railway Roslagsbanan
Roslagsbanan
-SL southern network:*Stockholms östra–Djursholms Ösby–Roslags Näsby–Vallentuna–Lindholmen–Kårsta *Stockholms östra–Djursholms Ösby–Roslags Näsby–Åkersberga–Österskär...
, 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
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...
. 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.
Environmental influence
Most of the phosphorusPhosphorus
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...
reaching the lake are most likely derived from the university, while 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...
contribution is derived from surrounding landscape and equal shares of 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...
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
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
s, even though presence of hydrogen sulphide 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 phytoplanktonPhytoplankton
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...
is low in August with exceptional Blue Green Algae, 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...
, and Golden Algae
Golden algae
The golden algae or chrysophytes are a large group of algae, found mostly in freshwater.The term "chrysophyceae" should not be confused with the term Chrysophyta, which is more ambiguous.-Members:...
. Occurrence of 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"...
is more varied with several species of Rotifer
Rotifer
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696, and other forms were described by Anton van Leeuwenhoek in 1703...
s, Cladocera
Cladocera
Cladocera is an order of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed. They are ubiquitous in inland aquatic habitats, but rare in the oceans. Most are long, with a down-turned head, and a carapace covering the apparently...
ns, and Copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s. Among the 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 in the lake Fennel Pondweed
Potamogeton
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed...
is notable as it normally only occurs in sea bays. Other aquatic plants and nymphoides
Nymphoides
Nymphoides 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 leaves that hold the small flowers above the water surface. Flowers are sympetalous,...
include Rigid Hornwort
Hornwort
Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant.Hornworts may be found worldwide,...
, Broad-leaved Pondweed
Potamogeton
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed...
, Perfoliate Pondweed
Potamogeton
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae. Most are known by the common name pondweed, although many unrelated plants may be called pondweed, such as Canadian pondweed...
, Water-Starwort
Callitriche
Callitriche is a genus of largely aquatic plants known as water-starworts. Previously, it was the only genus in the family Callitrichaceae. However, according to the APG II system this family is now included in the Plantaginaceae...
, Nymphaea Alba
Nymphaea alba
Nymphaea alba, also known as the European White Waterlily, White Lotus, or Nenuphar, is an aquatic flowering plant of the family Nymphaeaceae....
, Lemna
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 Chara Tomentosa
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:...
(for which the lake is, together with Kyrksjön
Kyrksjön
Kyrksjön is a small lake in Bromma, a western suburb in Stockholm, Sweden. Named after its vicinity to the old church Bromma kyrka, the lake was made part of the nature reserve Kyrksjölöten in 1997...
, the only locale in Stockholm).
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
Bithynia leachii is species of small freshwater snail with an operculum, an aquatic prosobranch gastropod mollusk in the family Bithyniidae.-Shell description:The shell of the species grows to be 6.5 mm in maximum dimension....
and Gyraulus crista
Gyraulus crista
Gyraulus crista, commonly called the Nautilus ramshorn, is a minute species of freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.Synonyms:* Armiger crista* Planorbis crista...
, were earlier considered as endangered. Noteworthy is also the population of several freshwater mussels, Duck mussel
Duck mussel
Duck mussel, Anodonta anatina, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.Synonym: Anodonta piscinalis Nilsson, 1823Subspecies:*Anodonta anatina anatina...
and Swan mussel
Swan mussel
The swan mussel, Anodonta cygnea, is a large species of freshwater mussel, an aquatic bivalve mollusc in the family Unionidae, the river mussels....
, and Hippeutis complanatus
Hippeutis complanatus
Hippeutis complanatus, or the flat ram's-horn snail, is a species of minute air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk or micromollusk in the family Planorbidae, the ram's horn snails....
, the latter two declining. A species of 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...
new in Sweden has been reported in the lake just like did the rare Hairy Dragonfly
Hairy Dragonfly
Brachytron is a monophyletic genus of European dragonfly of the family Aeshnidae containing the Hairy Dragonfly , also known as the Hairy Hawker.- Description :...
. An inventory of dragonfly larvae in 2000 unveiled several other species (mostly Red-eyed Damselfly
Red-eyed Damselfly
Red-eyed Damselfly Erythromma najas is a member of the damselfly family Coenagrionidae.-Appearance:The species is a small damselfly, long, predominantly black with iridescent blue markings. The male resembles blue-tailed damselflies but is distinguished by its large, spaced eyes that are a deep red...
but also Common Blue Damselfly
Common Blue Damselfly
The Common Blue Damselfly or Northern Bluet is a European damselfly.The species can reach a length of 32 to 35 mm...
, Azure Damselfly
Azure Damselfly
The Azure Damselfly is a species of damselfly found in most of Europe. It is notable for its distinctive black and blue colouring.-Males:...
, Variable Damselfly
Variable Damselfly
Coenagrion pulchellum, the Variable Damselfly or Variable Bluet, is a European damselfly. Despite its name, it is not the only blue damselfly prone to variable patterning....
, and Northern Damselfly (Coenagrion hastulatum). Fish population reflects the shortage of oxygen with an absence of Carp bream
Carp bream
The common bream, freshwater bream, bream, bronze bream or carp bream, Abramis brama, is a European species of freshwater fish in the family Cyprinidae....
and Silver bream and an abundance of 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...
, 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 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...
dating back to before the dredging. The outlet forms a threshold for migrating species.
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...
are breeding in the lake, just like are occasionally 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...
and 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....
(introduced in Sweden in the 1930s). Marsh Warbler
Marsh Warbler
The Marsh Warbler, Acrocephalus palustris, is an Old World warbler currently classified in the family Acrocephalidae. It breeds in temperate Europe and western Asia and winters mainly in south east Africa...
and Gray Heron are often seen among the reed. Even though reed have been cleared to attract wader
Wader
Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...
s, as a locale for birs, the lake hasn't meat expectations much due to neglected attention of the canals and islands. There are three species of protected 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...
s in the lake: 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...
, 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...
. The deers once abundant in the area have been superseded by Roe Deer
Roe Deer
The European Roe Deer , also known as the Western Roe Deer, chevreuil or just Roe Deer, is a Eurasian species of deer. It is relatively small, reddish and grey-brown, and well-adapted to cold environments. Roe Deer are widespread in Western Europe, from the Mediterranean to Scandinavia, and from...
s.
Visiting
The lake and the national city park are easily accessible by bus, metro, bicycle, or by foot. Nearest metro station is UniversitetetUniversitetet
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....
.