EutrophicationEutrophication

Process of EutrophicationProcess of Eutrophication

natural process of the aging of a natural process of the aging of a body of water body of water

As more nutrients enter the water As more nutrients enter the water more organisms live and die and add more organisms live and die and add their organic molecules to the their organic molecules to the decaying / recycling processdecaying / recycling process

Bodies of water evolve from Bodies of water evolve from oligotrophic to eutrophicoligotrophic to eutrophic

Process continuedProcess continued

Eutrophication can be accelerated by Eutrophication can be accelerated by human activitieshuman activities– Increasing levels of nitrates and Increasing levels of nitrates and

phosphatesphosphatesDetergentsDetergentsSewageSewageFertilizers from agricultural runoffFertilizers from agricultural runoff

““death” of Lake Erie, 1960’sdeath” of Lake Erie, 1960’s

Large amounts of detergents and Large amounts of detergents and fertilizers dumped in to lake fertilizers dumped in to lake

Caused increase of algae growth Caused increase of algae growth – Algal bloomAlgal bloom

The decomposition of dead algae The decomposition of dead algae uses tremendous amounts of oxygen uses tremendous amounts of oxygen causing death to fish and other causing death to fish and other organisms at higher trophic levelsorganisms at higher trophic levels

““death” of Lake Erie, continueddeath” of Lake Erie, continued

Lake Erie declared “dead”Lake Erie declared “dead” Prompted a ban on phosphates in Prompted a ban on phosphates in

detergents in the late 1960’sdetergents in the late 1960’s Within a decade, Lake Erie Within a decade, Lake Erie

reboundedrebounded– Still suffers from other forms of pollutionStill suffers from other forms of pollution

Impacts of eutrophicationImpacts of eutrophication As oxygen levels deplete from As oxygen levels deplete from

decomposers, other aerobic decomposers, other aerobic organisms suffer and die contributing organisms suffer and die contributing to the decomposition process to the decomposition process (Positive Feedback)(Positive Feedback)

Can lead to “death” of a body of Can lead to “death” of a body of waterwater– Decrease in species diversityDecrease in species diversity– Stagnant putrid waterStagnant putrid water