….. EUTROPHICATION

…..EUTROPHICATION

When lakes, streams and estuaries are overfertilized, excessive production of aquaticorganic matter can become a water qualityproblem and as a result the eutrophication process can be enhanced!

Eutrophication is a natural process!

However, humans in their everyday activities can exacerbate the process:

Point sources (can locate the cause)• Sewage treatment plant discharges• Storm sewer discharges• Industrial dischargesNon-point sources (can’t locate the cause, it’s

everywhere)• Atmospheric deposition• Agricultural runoff (fertilizer, soil erosion)• Septic systems

Eutrophication: a process by which a body ofwater progresses from its origin to itsextinction. This process happens in stages.

BEFORE EUTROPHICATION

AFTER EUTROPHICATION

LACK OF OXYGEN

GROWTH OF BACTERIA

DEATH OF PLANTS

SUFFOCATION

GROWTH OF PLANTS

ADDITION OF NITRATES

Eutrophication process in 6 stages

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The process of Eutrophication cont.

Biochemical Oxygen Demand (BOD).

This measures the rate of oxygen consumption by a sample of water, and therefore gives a good indication of eutrophication. A high BOD means lots of organic material and aerobic microbes, i.e. eutrophication

LACK OF OXYGEN

GROWTH OF BACTERIA

DEATH OF PLANTS

SUFFOCATION

GROWTH OF PLANTS

ADDITION OF NITRATES

Eutrophication process in 6 stages

Before increases in nutrients:

Acceleration of eutrophication :

Results of eutrophication :

Photo 1: Algal bloom in a lake.

Photo 1: Algal bloom in a lake.

Photo 2: Overgrowth of floating aquatic plants.

Photo 23: Lake Biwa, the largest lake in Japan during summer time showing overgrowth of aquatic plants.

Photo 4: Fish mortality due to lack of oxygen in an Indonesian lake.

Put in order the stages of Eutrophication!

LACK OF OXYGEN

GROWTH OF BACTERIA

DEATH OF PLANTS

SUFFOCATIONGROWTH OF PLANTS

ADDITION OF NITRATES