Eutrophication is the accumulation of nutrients in aquatic ecosystems that alters plant and animal populations and brings changes to the community structure. It occurs naturally over hundreds or thousands of years but human activities like sewage, fertilizer runoff and industrial discharges can accelerate the process through cultural eutrophication over just decades. Major sources of excess nutrients are agricultural fertilizers, domestic sewage and livestock wastes which provide both inorganic and organic nutrients. Eutrophication impacts water chemistry by increasing levels of substances like pH, dissolved oxygen, carbon dioxide, ammonia, nitrates/nitrites and phosphates.

1. EUTROPHICATION
DR.SUJIT GHOSH
JK COLLEGE
PURULIA

2. Cause of eutrophication humans in their
everyday activities can exacerbate the process:
Point sources
(can locate the
cause)
Sewage
treatment plant
Non-point
sources (can’t
locate the cause,
it’s everywhere)
Atmospheric
depositiontreatment plant
discharges
Storm sewer
discharges
Industrial
discharges
Atmospheric
deposition
Agricultural
runoff (fertilizer,
soil erosion)
Septic systems

3. EUTROPHICATION
It is the
accumulation of
nutrients in aquatic
ecosystems.
It alters the dynamics
of a number of plant,
animal and bacterial
populations; thus,
bringing about
changes in community
structure.
It is a form of water
pollution and like all
other forms of
pollution is the result of
human activities
influencing ecological
cycles.
The nutrient
enrichment of an
aquatic ecosystem.
Natural
Eutrophication -- a
process that occurs
as a lake or river
ages over a period
of hundreds or
thousands of years.
Cultural
Eutrophication -- a
process that occurs
when humans
release excessive
amounts of nutrients;
it shortens the rate ofthousands of years.
Lake classification based on
nutrient content and
production of organic
matter.
Oligo- nutrient
poor;
meso- middle
nutrient;
eu- nutrient rich.
it shortens the rate of
aging to decades.
Major Sources of Excess Nutrients
Major sources of excess
nutrients are agricultural
fertilizers, domestic sewage and
livestock wastes.
1. Agricultural fertilizers
provide inorganic nutrients.
2. Sewage and wastes provide
both inorganic and organic
nutrients.

4. ADDITION OF NITRATES
GROWTH OF PLANTS
DEATH OF PLANTS
EUTROPHICATION
DEATH OF PLANTS
GROWTH OF BACTERIA
LACK OF OXYGEN
EUTROPHICATION

5. fertilisers
sewage
(liquid domestic
and industrial waste)
minerals
esp. nitrates
minerals
esp. phosphates
eutrophication
organicm
detritus
moredecomposers
useupoxygen
algal bloom
competition
for light
consumers can't
consume fast enough
dead plants dead algae
detritus
organicmaterial
useupoxygen
byaerobicrespiration
(increasedBOD)
aerobesdie
(invertebrates,
fish,etc)
anaerobicbacteria
thrive.Release
NH,CH,HS4 4 2

6. EUTROPHICATION
NATURAL – LAKE
CLASSIFIED BASED
ON
Oligo- nutrient
poor;
CULTURAL
The addition of
excess nutrients
from a variety of
sources results in
Eutrophication brings about changes in
water chemistry.
These include:
pH
Dissolved O2
CO2
Ammonia
Nitrates/Nitrites
Phosphates
EUTROPHICATION TYPES
RESULTS
poor;
meso- middle
nutrient;
eu- nutrient rich.
sources results in
the rapid aging of
aquatic ecosystems.
During this process
the species
composition of the
aquatic community
changes.
Phosphates

7. pH -- The pH of water reflects the CO2 contents as well as the presence of
organic and inorganic acids. Values below 5 and above 9 are definitely
harmful to fish and limit growth of algal and invertebrate populations.
Dissolved O2 -- The amount of dissolved oxygen in water varies with
temperature and pressure; high temperature or pressure, low oxygen.
Most invertebrates die if oxygen levels fall below 4-5 mg/l for extended
periods of time. Game fish (bass, perch, trout, etc) require oxygen to be in
the range of 8-15 mg/l.
CO2 -- Carbon dioxide is largely a product of aerobic and anaerobic
decomposition of organic matter. It reacts with water to form carbonic
acid. Normal concentrations are usually less than 1 mg/l. Fish are affected
at higher levels and continued exposure to 10mg/l or more is fatal to many
species.species.
Phosphates -- Present in low quantities in natural waters; less than 0.01
mg/l. Released during decomposition. High levels stimulate algal blooms
Ammonia (NH3 or NH4
+) -- Ammonia is a product of decomposition of
animal and plant protein. It is an important plant nutrient. Natural bodies
of water contain > 1 mg/l. Levels higher than this stimulate algal growth
and are toxic to fish.
Nitrates/Nitrites -- These N containing compounds are formed during
decomposition and are inter-converted by certain species of bacteria.
Natural concentrations rarely exceed 10 mg/l and are often > 1mg/l.