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…..EUTROPHICATION
When lakes, streams
and estuaries are over
fertilized, excessive
production of aquatic
organic matter can
become a water
quality
problem 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 discharges
Non-point sources (can’t locate the cause, it’s
everywhere)
• Atmospheric deposition
• Agricultural runoff (fertilizer, soil erosion)
• Septic systems
BEFORE EUTROPHICATION
AFTER EUTROPHICATION
Eutrophication: a process
by which a body of
water progresses from its
origin to its
extinction. This process
happens in stages.
Eutrophication process in 6 stages
ADDITION OF NITRATES
GROWTH OF PLANTS
DEATH OF PLANTS
GROWTH OF BACTERIA
LACK OF OXYGEN
SUFFOCATION
s e wa g e
a n(ldi qi nu di du sd torima le ws at i sc t e )
m i n e ra l s
e s p . n i t ra t e s
m i n e ra l s
e s p . p h o s p h a te s
e u t ro p h i ca t i o n
a lg a l b lo o m
or
ganic m
at
er ial
The process of
Eutrophication
f e rt i l i s e rs
c o m p e titio n
fo r lig h t
c o n s u m e rs c a n ' t
c o n s u m e fa s t e n o u g h
d e a d p la n ts
d e a d a lg a e
d e t ri t u s
The process
d e a d p l a n of
t s Eutrophication
d e a d a l g a e cont.
d e t ri t u s
m o re d e c o m p o s e rs
use up oxygen
b y a e ro b i c re s p i ra t i o n
(i n c re a s e d B O D )
a e ro b e s d i e
(i n v e rt e b ra t e s ,
fis h , e tc )
a n a e ro b i c b a c t e ri a
t h ri v e . R e l e a s e
N H ,4 C H ,4 H S2
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
Eutrophication process in 6 stages
ADDITION OF NITRATES
GROWTH OF PLANTS
DEATH OF PLANTS
GROWTH OF BACTERIA
LACK OF OXYGEN
SUFFOCATION
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
DEATH OF PLANTS
GROWTH OF BACTERIA
GROWTH OF PLANTS
SUFFOCATION
ADDITION OF NITRATES