Vesijärvi is a

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

of near

Lahti Lahti (; ) is a city in Finland and the regional capital of Päijät-Häme. It is located in the Finnish Lakeland. The population of Lahti is approximately , while the Lahti sub-region, sub-region has a population of approximately . It is the mo ...

in southern Finland. It suffered severe effects of

eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

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

Geography

The lake may be divided into several parts, the notable ones being: *, the southern area *Kajaanselkä, the northern area, the largest part *, the southwestern area * *The Komonselkä strait connects Enonselkä with Kajaanselkä. The lake is connected to the Pikku-Vesijärvi pond. It is also connected to Lake Päijänne northwards via the .

Cyanobacteria bloom remediation

* Biomanipulation is an approach that applies the top-down model of community organization to alter ecosystem characteristics. * Ecologists used

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

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 Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

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.

In popular culture

* The ninth track on

Geographer A geographer is a physical scientist, social scientist or humanist whose area of study is geography, the study of Earth's natural environment and human society, including how society and nature interacts. The Greek prefix "geo" means "earth" a ...

's 2012 album ''Myth'' is titled "Vesijärvi".

References

External links

Kymi basin Lakes of Lahti {{SouthernFinland-geo-stub

Geography

Cyanobacteria bloom remediation

In popular culture

See also

References

External links