5.4 eutrophication connor. what is it? excessive richness of nutrients (especially phosphates and...
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5.4 EUTROPHICATION
Connor
What is it?
excessive richness of nutrients (especially phosphates and nitrates) in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.
Occurs in slow moving rivers and lakes primarily
Eutrophic means well nourished When effects are undesirable it is considered
a form of pollution
The Processes of Eutrophication 5.4.1
Fertilizer run-off and sewage discharge flow into the body of water
Run-off builds up at the bottom of the body of water
Excess promotes plant growth (primarily algae)
High level of organic matter and decomposing organisms deplete available oxygen in the water
Causes the death of other organisms ie. fish
Over time the increased amount of sediment can raise the bed of the lake/river and allowing plants to colonize the edges eventually turning the area into dry land (in some cases)
Impacts of Eutrophication5.4.2
Species diversity decreases and the dominant biota changes The animal and plant life of a particular region, habitat, or
geological period Plant and animal biomass increase Turbidity increases Turbidity is the amount of particulate matter that is
suspended in water Rate of sedimentation increases, shortening the lifespan of
the lake Anoxic conditions may develop Anoxic waters are areas of sea water, fresh water or
groundwater that are depleted of dissolved oxygen
Pollution Management Strategies5.4.3
Implement research and monitoring programs for eutrophication
Raise awareness of eutrophication Implement regulations to reduce nutrient losses Create incentives to encourage nutrient
reducing actions ie. tax subsidies Preserve and restore natural bodies of water
that are affected by eutrophication Create institution to enforce policies and
regulations
Example: Toxic Water in Toledo What happened? Sewage
from treatment plants and fertilizer from farms were discharged into the lake causing an algae bloom
The bloom was close enough to the city’s intake valve that the water being sent to the city was toxic rendering it undrinkable
Regulations have been set but officials have not mandated any restrictions as of yet.
Links
Animated video NatGeo Eutrophication Video Eutrophication Song BBC Bitesize Eutrophication
Sources
BBC USGS Lenntech WRI NBC Toledo Water Crisis