Vesijärvi is a lake of 111 square kilometres (43 sq mi) near Lahti in southern Finland. It suffered severe effects of eutrophication in the 1960s and a restoration programme began in the 1970s; by the start of the 2020s, the lake's water quality and ecosystem had significantly improved.[2] The Enonselkä Basin is a part of Vesijärvi.

Vesijärvi
Vesijärvi at night
Vesijärvi is located in Finland
Vesijärvi
Vesijärvi
LocationPäijänne Tavastia
Coordinates61°04′58″N 025°32′18″E / 61.08278°N 25.53833°E / 61.08278; 25.53833
Basin countriesFinland
Max. length25 km (16 mi)
Surface area107.57 km2 (41.53 sq mi)
Average depth6 m (20 ft)
Max. depth42 m (138 ft)
Water volume484×10^6 m3 (17.1×10^9 cu ft)
Shore length1181 km (112 mi)
Surface elevation81.4 m (267 ft)
SettlementsAsikkala, Lahti
References[1]
1 Shore length is not a well-defined measure.
View from harbour
Road that separates Pikku-Vesijärvi from Vesijärvi

The name of the lake means literally 'Water Lake'.

Cyanobacteria bloom remediation

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  • Biomanipulation is an approach that applies the top-down model of community organization to alter ecosystem characteristics.
  • Ecologists used cyanobacteria blooms as an alternative to using chemical treatments.
  • Lake Vesijärvi was polluted by city sewage and industrial wastewater until 1976, at which point pollution controls reduced these inputs. By 1986 massive blooms of cyanobacteria began occurring, as well as dense populations of roach, a fish that benefited from the pollution's mineral nutrients. Roach eat zooplankton that otherwise keep cyanobacteria in check. To remediate this problem, ecologists removed about a million of kilograms of fish, reducing roach to 20% of their former abundance, between 1989 and 1994, and stocked the lake with pike perch which eats roach. The water has since become clear, and the last cyanobacteria bloom was in 1989.[3]
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  • The ninth track on Geographer's 2012 album Myth is titled "Vesijärvi".

See also

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References

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  1. ^ Finnish Environment Institute: Finnish lakes larger than 40 square kilometers Archived July 25, 2011, at the Wayback Machine
  2. ^ "Sinisiä särkiä, leväpuuroa ja kelluvaa kakkaa – Lahden saastuneen Vesijärven puhdistumisesta tuli hieno onnistumistarina" [Blue roach, algae porridge and floating poo - Lahti's polluted Vesijärvi turned into a success story] (in Finnish). Yle. 6 July 2023. Retrieved 23 July 2023.
  3. ^ "Vesijärvi - Lake Ecosystem Dynamics". www.helsinki.fi. Archived from the original on 2012-10-06.
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  Media related to Vesijärvi at Wikimedia Commons

 
Location in Finland (yellow dot)