What is Eutrophication and it's cause, what impacts on environment as well as on human and how to control it. All details shown in this ppt plus one case study.
2. What is Eutrophication?
A process whereby water bodies receive excessive
amounts of nutrients, which results in excessive plant
growth (aka algal bloom)
Mainly arises from the oversupply of phosphate and
nitrate nutrients.
Anthropogenic Eutrophication – the pollution that
humans cause with the release of sewage effluent and
fertilizers into natural waters.
Anthropogenic eutrophication has caused a great
loss of Biodiversity. Mostly seen in marine
habitats.
3. What are Algal Booms?
Algal/marine/water
bloom=“rapid increase in the
population of algae in an aquatic
system” –green, yellowish-brown
or red.
Fertilizers (used in farming) run-
off into water – cause increase in
nutrient level;
As a result phytoplankton grow
and reproduce more rapidly,
resulting in algal blooms.
5. Causes of Eutrophication
The enrichment of water by nutrients can be of natural
origin but it is often dramatically increased by human
activities. This occurs almost everywhere in the world.
main sources of nutrient input are:
Runoff
Erosion and Leaching from fertilized agricultural
areas
Sewage from cities and industrial wastewater
Atmospheric deposition of nitrogen (from animal
breeding and combustion gases)
Other point and non-point sources of pollutants
6. Factors Supporting the
Development of Eutrophication
Time of renewal of water.
Geological features such as the shape of the bottom
of the water bodies.
Thermal stratification of stagnant water bodies
(such as lakes and reservoirs)
Temperature and light influence the development
of aquatic algae.
9. Ecological impacts
Macrophyte invasions impede or prevent the growth
of other aquatic plants.
Only the more tolerant animal species can survive due
to algal bloom.
Turbidity of water increases.
Release of cyanotoxins by cyanobacteria are
recognized to have caused the deaths of wild animals,
farm livestock, pets, fish and birds in many countries.
Decreased oxygen levels can have a number of
secondary water quality impacts.
10. Impact on people
Economic
– Tourism income decreases
– Fishing is abolished
Health
– Damaged sea-food may cause illnesses
– Dangerous for humans due to toxic substances
– May cause neurological disorders.
11. Impact on ecosystems
Decrease of species
diversity
Emigration of aquatic
species
Toxic chemicals are
produced [Cloern]
Combustion of fuels => N
oxides
Fertilizers => NH3
12. Prevention
1. Effectiveness
Sources of nutrients must be identified and evaluated,
and then cost-effective methods of controls must be
implemented.
2. Minimizing nonpoint pollution
The following steps are recommended to minimize the
amount of pollution that can enter aquatic ecosystems
from ambiguous sources;
i. Riparian buffer zones
Riparian buffer zones can be created near waterways
in an attempt to filter pollutants; sediments and
13. …….nutrients are deposited
here instead of in water.
ii. Prevention policy
Laws regulating the discharge and treatment of sewage
can led to dramatic nutrient reductions to surrounding
ecosystems.
iii. Nitrogen testing and modeling
Soil Nitrogen Testing (N-Testing) is a technique that
helps farmers optimize the amount of fertilizer
applied to crops. By testing the soil and modeling the
bare minimum amount of fertilizer needed, farmers
reap economic benefits while the environment
remains clean.
14. Control
Within-lake actions
Reduce mineralization
– Remove organic P before it is
mineralized;
a. Dredging
b. Macrophyte harvesting
Reduce transport of inorg. P to
epilimnion
– Hypolimnetic water withdrawal
15. Reduce P release from sediments
– Hypolimnetic aeration
Lake Aeration
P release from sediments is greatly enhanced by anoxic
conditions under which iron oxides dissolve and release
all P sorbed to their surfaces.
17. In the Baltic Sea, all the areas are affected by
eutrophication
Number of phytoplankton increases (especially
cyanobacteria)
This bacterium has increased, because of the increase
in nutrient concentrations and due to the changes in
the seasonal availability and large nutrient proportions
Cyanobacteria bloom (Nodularia spumigena) in the
western Baltic.
Source of eutrophication in this area – increase in
phytoplankton, consisting of many harmful bacteria
causing damage to the environment
18. Impacts Includes…
Reductions in biodiversity
Reductions in the natural resources of dermersal fish
and shellfish
Reduced income from maricultures of fish and
shellfish
Reduced recreational value and income from tourism
Increased risk of poisoning of animals including
humans byalgal toxins
19. Solutions
The Baltic Sea states and the North Sea states -
decided to aim at a 50 % reduction of the N and P load
from land compared to the level in the middle of the
1980s.
It is expected that the directives and especially the
recently decided water framework Directive (the urban
wastewater treatment directive, 2000/60/EC) will
reduce the nutrient loads to the European coastal
areas and the eutrophication impacts to an acceptable
level.
