The seminar by Ponnanna M.B. at Davangere University focused on eutrophication, defined as the nutrient enrichment of water bodies leading to excessive plant and algal growth, primarily due to human activities such as agricultural runoff and sewage discharge. It discussed types, mechanisms, sources, effects, and controls of eutrophication, highlighting both its ecological impacts and potential benefits like increased biodiversity. The conclusion emphasized the need for effective management practices to reduce nutrient inputs and mitigate eutrophication's adverse effects on freshwater ecosystems.

1. DAVANGERE UNIVERSITY
MICROBIOLOGY SEMINAR
ON THE TOPIC
PRESENTED BY :
PONNANNA M. B
M.Sc. Microbiology.

2. CONTENTS
INTRODUCTION
TYPES OF EUTROPHICATION
MECHANISMS OF EUTROPHICATION
SOURCES OF EUTROPHICATION
EFFECTS OF EUTROPHICATION
SOME EXAMPLES OF EUTROPHIC LAKES
CONTROL OF EUTROPHICATION
SUMMARY
CONCLUSION
REFERENCES

4. INTRODUCTION
Eutrophication, in Greek sense is eutrophia, meaning
”nourish well”. Or more precisely hypertrophication, is
the enrichment of a water body with nutrients. This process
induces growth of plants and algae and due to the biomass
load, may result in oxygen depletion of the water body.
One example is the "bloom" or great increase
of phytoplankton in a water body as a response to
increased levels of nutrients. Eutrophication is generally
induced by the discharge of phosphate-
containing detergents, fertilizers, or sewage, into an aquatic
system.

6. TYPES OF EUTROPHICATION
1. Natural eutrophication
Although eutrophication is commonly caused by human activities, it can also
be a natural process, particularly in lakes. Paleolimnologists now recognise
that climate change, geology, and other external influences are critical in
regulating the natural productivity of lakes. Some lakes also demonstrate the
reverse process (meiotrophication), becoming less nutrient rich with time. The
main difference between natural and anthropogenic eutrophication is that the
natural process is very slow, occurring on geological time scales.
2. Cultural eutrophication
Cultural Eutrophication is the process that speeds up natural eutrophication
because of human activities . Due to some of the reasons like urbanization
, land runoff is accelerated and more nutrients such
as phosphates and nitrate are supplied to lakes and rivers, and then to
coastal estuaries and bays. Extra nutrients are also supplied by treatment
plants, fertilizers, farms, as well as untreated sewage in many cities.

7. NATURAL EUTROPHICATION CULTURAL EUTROPHICATION

8. MECHANISMS OF EUTROPHICATION
• Eutrophication arises from the oversupply of nutrients, which leads
to overgrowth of plants and algae. After such organisms die, the
bacterial degradation of their biomass consumes the oxygen in the
water, thereby creating the state of hypoxia.
• The primary limiting factor for eutrophication is phosphate.
Phosphorus is a necessary nutrient for plants to live, and is the
limiting factor for plant growth in many freshwater ecosystems. The
availability of phosphorus generally promotes excessive plant
growth and decay, on the other hand nitrogen in the form of nitrates
also play a vital role in the eutrophication process. Phosphates and
nitrates adheres tightly to the soil, so it is mainly transported by
leaching and erosion. Once translocated to lakes, the extraction of
phosphate becomes tough , hence the difficulty of reversing the
effects of eutrophication.
• The sources of these excess phosphates are phosphates in detergents,
industrial/domestic run-offs, and fertilizers emerging as the
dominant contributors to eutrophication.

9. • Sodium triphosphate, once a component of many detergents, was
a major contributor to eutrophication
• Enhanced growth of aquatic vegetation and algal blooms
disrupts normal functioning of aquatic ecosystem causing
various problems.
• The water becomes cloudy with a green , red or yellow shade
indicating the algal blooms. These blooms block the penetration
of sunlight into the water body, apparently the dissolved oxygen
level in the water body also decreases. Lack of oxygen kills the
aquatic plants and animals.
• Death of these organisms and life forms increases the level of
organic and inorganic matter, which require large amount of
oxygen for decomposition.
• Now the depletion of oxygen level leads to the accumulation of
nutrients unable to be decomposed. Slowly the aquatic
ecosystem is converted from aerobic to anaerobic condition,
increasing the number of anaerobes which apparently gives a
pungent odour generally produced by methanogens and sulphur
bacteria . Now this water ecosystem can no longer support life
also causing hazardous effects to the environment. Eventually
the aquatic ecosystem turns into a bog and gradually converts
into a terrestial ecosystem.

11. SOURCES OF EUTROPHICATION
• Point sources
Point sources are directly attributable to one influence. In point sources the nutrient
waste travels directly from source to water. Point sources are relatively easy to regulate.
• Nonpoint sources
Nonpoint source pollution is that which comes from diffused sources. Nonpoint sources
are difficult to regulate and usually vary spatially and temporally.
Point sources
• Wastewater effluent (municipal and
industrial)
• Runoff and leachate from waste disposal
systems
• Runoff and infiltration from animal
feedlots
• Runoff from mines, oil fields, unsewered
industrial sites
• Overflows of combined storm and sanitary
sewers
• Runoff from construction sites .
• Untreated sewage
Nonpoint sources
 Runoff from agriculture/irrigation
 Runoff from pasture and range
 Urban runoff from unsewered areas
 Septic tank leachate
 Runoff from construction sites >20,000
m²
 Runoff from abandoned mines
 Atmospheric deposition over a water
surface
Other land activities generating contaminants

13. EFFECTS OF EUTROPHICATION.
• Primary productivity increases and diversity of primary
producers varies.
• Growth of aquatic plants and algae reduces the light
penetration and also increases the turbidity . Death of
resident organisms takes place.
• DO level decreases and sedimentation rate increases.
• Species diversity is altered , inturn overall aquatic
ecosystem is effected.
• Accumulation of organic and inorganic nutrients.
• Conversion of aerobic environment to anaerobic inturn
altering the appearance , odour of the water body.
• Anaerobes produce toxins and usage of this water causes
health problems.
• Aquatic ecosystem is depleted.

14. SOME EXAMPLES OF EUTROPHIC LAKES.
• Udaisagar lake, situated around 13kms in the east of
Udaipur revealed high phosphate content due to discharge
of pollutants from surrounding phosphorite mines,
chemical factories , distillery and domestic effluents. This
lake shows a green shade of algal bloom witnessing
eutrophication.

15. • Dal is a lake in Srinagar , which is named the "Jewel in the crown
of Kashmir“. The lake is also an important source for commercial
operations in fishing and water plant harvesting. The lake covers
an area of 18 square kilometers (6.9 sq mi) and is part of a natural
wetland which covers 21.1 square kilometers.
Due to increasing urbanization , industrial discharge and use of
chemical fertilizers in and around the area has resulted in the
pollution of the lake causing eutrophication.

16. A view of chelur lake situated near Shimoga district, which is
densely covered by aquatic weeds and algal blooms. The
reason being the lake is surrounded by agricultural fields, the
application of fertilizers in there leach into the lake causing
hypertrophication.

17. CONTROL OF EUTROPHICATION.
Role of nitrogen and phosphorus is overwhelming in the
eutrophication process , which needs to be controlled and
affective measures need to be taken.
• Sources of nitrogen and phosphorus need to be checked
and prevented from entering the water body.
• Timely removal of sediments and overgrown aquatic
plants from the water bodies.
• Stimulation of algal food web.
• Industrial, municipal and domestic outflow need to be
treated prior to releasing. Use of fertilizers to be avoided.
• Physiochemical methods to be adopted for the removal of
excessive dissolved nutrients. Nitrogen testing to be done.
• Chemicals such as alum, lime , sodium aluminate can be
used to reduce the level of contamination.
However halting of eutrophication process is difficult, but
can be temporarily controlled to some extent.

18. SUMMARY
Eutrophication is most commonly associated with
the cultural pollution of water with excessive
nutrients. The effect of this is rapid increase in
biomass, causing both positive and negative
effects. Positive effects relate to use as source of
fish food, improves biodiversity, enhance
ecotourism. Negative effects include decrease in
aquatic diversity, human health impacts , ecological
impacts. Overall the eutrophication process need to
be controlled and affective measures to be
implemented in order to replenish the water bodies.

19. CONCLUSION
Human induced eutrophication has heavily degraded
freshwater systems worldwide by reducing water quality and
altering the structure and functioning of ecosystem. With the
demand of freshwater sources expected to increase
substantially, these anthropogenic influences have severe
environmental and economic repercussions. The first
obvious step towards protection and restoration of lake is to
divert or treat excessive phosphorus inputs via nutrient
lodging restrictions. Living organisms can be used as
monitors of trophic status of lakes. Nitrogen testing to be
done to avoid use of nitrogenous compounds.
Phytochemical tests can be achieved to remove excessive
nutrients. Effluents and runoff water into the lake need to be
treated .
It takes a very long time to overcome the problem of
eutrophication, but can be minimized to a substantial level
by incorporating some of the preventive measures.

20. REFERENCES
1. Maier, R. M., Pepper, I. L. and Gerba, C. P. 2009.
Environmental Microbiology ,2nd edn. Academic press,
Amsterdam, 598 pp.
2. Atlas, R. M. 1997.Principles of Microbiology,2nd edn.
McGraw Hill education , New Delhi, 1298 pp.
3. Atlas, R. M. and Bartha, R. 2009. Microbial ecology,
fundamentals and applications, 4th edn. Pearson
education, New Delhi. 704 pp.
4. Toratora,G.J., Funke,B.R. and Case,C.L. 2007.
Microbiology an introduction, 11th edn. Pearson
education, South Asia. 975 pp.