Notes on Freshwater Biology

Essay by cripplestickmick March 2004

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Freshwater such as lakes and rivers have determined the location of habitation through out history. Witness all the great cities: Rome and Cairo to name but two are built on rivers: The Tiber and the Nile.

The reason was the in history freshwater was important for drinking water, food, transport and a disposal route for waste. The fish obtained from the rivers was an important source of protein for the peoples living nearby.

Now in the 21st century freshwater fishing and other recreational uses of water such as sailing and narrowboat holidays are economically important.

The downside of the proximity of freshwater to habitation centres is the waterborne disease or diseases with a freshwater vector such as malaria, amongst others.

If we look at a map of Kent from the 17th century we can see the effects of proximity on the demographic makeup of the area.

The marshes were later drained to provide farmland.

Freshwater can be damaged in many ways, there are four main ways of damaging freshwater systems these are: Acidification, Drainage, Eutrophication, and River Engineering.

Acidification normally occurs in the uplands as a result of atmospheric pollution.

Drainage occurs to provide farmland in the lowland marsh systems or in the upland marshes to provide forestry.

Eutrophication occurs when excesses of Nitrogen and phosphorous and other nutrients are added to the water from various sources.

River Engineering such as modification to provide hydro electric power stations, millraces for water powered mill wheels, and other uses.

Damage can also occur from recreational damage (sailing in the Norfolk Broads), introduced species, toxic pollution, abstraction for irrigation, inter basin transfer salination, sedimentation, fish farming and dam building.

Aldo Leopold said that "...mechanised man, having rebuilt the landscape, is now rebuilding the waters. The sober citizen who would never submit his watch...