Author
Abstract
The term "eutrophic" refers to system rich in nutrients, and hence Eutrophication
means nutrient enrichment, particularly by increasing levels of nitrogen and
phosphorus [1]. In lakes, phosphorus is generally regarded as the limiting nutrient for
primary production [2] implying that increasing phosphorus concentrations will result
in increasing production of phytoplankton and benthic algae. Excessive amounts of
phytoplankton cause low Secchi depths and may consequently wipe out the benthic
flora by shading the light [3]. Toxic cyanobacteria tend to bloom when nutrient levels
are high [4]. Apart from being a nuisance in their own right, settling phytoplankton
may cause anoxia in hypolimnetic waters as their decomposition consumers oxygen
[5], and this may result in extinction of the benthic fauna [6] and fish feeding on such
animals. Altogether, these Eutrophication effects threaten the foundations of aquatic
ecosystems. The low oxygen levels in hypolimnetic waters associated with
Eutrophication may also cause mobilization of phosphorus in the sediments, thus
inducing a feedback mechanism where already high nutrient levels increase even more.
Keywords
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