Transcript Richard Sandford, Plymouth University
Eutrophication
Eutrophication in the Sea of Azov. Source: SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAG
Developed by Richard Sandford with contributions from Martin Bloxham and Paul Worsfold ,
The lecture will:
1.
eutrophication 2. Explain the
of eutrophication 3. Discuss the
of eutrophication 4. Look at the
consequences of eutrophication 5. Look at
6. Explain how to
Eutrophication 7. Examine BLACK SEA CASE STUDY 8. Present
and
to information sources
1. Defining Eutrophication
Most limnologists consider eutrophication as an increase in the rate of supply of organic matter to an ecosystem .
For marine scientists, eutrophication (GESAMP, 1990) is “used simply to mean ‘enhanced nourishment’ and refers to the stimulation of aquatic plant growth by mineral nutrients, particularly the combined forms of phosphorus or nitrogen ”.
For more information on defining eutrophication, click
2. Causes of Eutrophication
The immediate causes of eutrophication are listed below. For more detailed information on the underlying causes of eutrophication, click on the immediate cause of interest:
2.2 Increased recycling/ mobilisation of nutrients
2.3 Trapping of nutrients (e.g. in river impoundments)
3. Environmental Impacts of Eutrophication
Here are some of the impacts of eutrophication. The consequences of each of these impacts will be explained in the lecture. For more information click on the impact of interest:
3.1 Decrease in the transparency of water
3.2 Development of anoxic conditions (low oxygen levels)
3.4 Loss of habitat (e.g. Sea grass beds)
3.6 Decrease in species diversity 3.7 Change in the aesthetic value of the water body
4. Socio-economic Consequences of Eutrophication
Here are some of the main socio-economic consequences of eutrophication:
4.1 Increased vegetation may impede water flow and the movement of boats 4.2 The water may become unsuitable for drinking even after treatment 4.3 Decrease in the amenity value of the water (e.g. it may become unsuitable for water sports such as sailing) 4.4 Disappearance of commercially important species (such as trout) 4.5 Loss of tourism/recreation (swimming, boating) 4.6 Loss of aesthetic value: visual disamenity of algal blooms in lakes
5. Remediation Measures
A reduction in the extent of artificial eutrophication can (in principle) be achieved by:
5.1 Reduction in the use of phosphates as builders in detergents
5.2 Reduction in the use of nitrate containing fertilisers
5.3 Implementation of tertiary sewage treatment methods which remove phosphate and nitrate
5.4 Improvements in agricultural practices (economising on fertiliser use and improving land use) 5.5 Aeration of lakes and reservoirs to prevent oxygen depletion particularly during algal blooms 5.6 Restoration of natural wetlands, efficient in nutrient removal 5.7 Removing phosphate-rich plant material from affected lakes 5.8 Removing phosphate-rich sediments by dredging
6. Monitoring of Nutrients
This section looks at:
• The biogeochemistry of nutrients (nitrogen, phosphorus and silicon) • Methods of nutrient sampling and storage handling • Techniques for the determination of nutrients in aquatic environments • Validation of nutrient data
For more information on nutrient monitoring, click
Here
7. References
Mee, LD, Bloxham, M, Glegg, GA, Hart, V, Beaumont, N and Payne, S (2000) Global International Waters Assessment; draft methodology, University of Plymouth.
GESAMP (1990) (IMO/FAO/UNESCO-IOC/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the Scientific Aspects of Marine Pollution) The State of the Marine Environment. GESAMP No. 39, 111pp, London.
Anderson, N.J. , Historical changes in epilimnetic phosphorus concentrations in six rural lakes in Northern Ireland, Freshwater Biology, 1997, 38, 427-440.
Bloxham, M., Nixon, E., McGovern, E., Rowe, A., Smyth, M. and Duffy, C., Winter Nutrient Monitoring of the Western Irish Sea- 1990-2000, Irish Marine Environment and Health Series, 2001.
Useful Web links are on the next page.....
8. Useful Links
Environment Agency (EA) Home EA Water Framework Directive EA Nutrients in rivers, lakes and coastal waters EA Excess nutrients in rivers, lakes and coastal waters - an overview EA Nitrate in rivers and groundwater Defra Nitrates from Agriculture Defra Water Framework Directive Water UK Home United Nations Environment Programme (UNEP) Eutrophication information Institute of Grassland and Environmental Research (IGER) Home
More useful links are on the next page.....
8. Useful Links
Global International Waters Assessment (GIWA) Web site Home Oslo and Paris Commission (OSPAR) Quality Status Reports (QSR2000) Home Joint Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP) Home European Statistics (EuroStat) Home Irish Marine Institute Home Department of Agriculture and Rural Development Northern Ireland (DARDNI) Home Irish Environmental Protection Agency (EPA) Home Helsinki Commission (HELCOM) Home