Predictive Modeling of Hawiza Marsh Eutrophication

Abstract

The term "eutrophic" refers to system rich in nutrients, and hence Eutrophicationmeans nutrient enrichment, particularly by increasing levels of nitrogen andphosphorus [1]. In lakes, phosphorus is generally regarded as the limiting nutrient forprimary production [2] implying that increasing phosphorus concentrations will resultin increasing production of phytoplankton and benthic algae. Excessive amounts ofphytoplankton cause low Secchi depths and may consequently wipe out the benthicflora by shading the light [3]. Toxic cyanobacteria tend to bloom when nutrient levelsare high [4]. Apart from being a nuisance in their own right, settling phytoplanktonmay 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 suchanimals. Altogether, these Eutrophication effects threaten the foundations of aquaticecosystems. The low oxygen levels in hypolimnetic waters associated withEutrophication may also cause mobilization of phosphorus in the sediments, thusinducing a feedback mechanism where already high nutrient levels increase even more.