Ecology of Shallow Lakes
2380555 (3 0)3

Catalogue Description

This course aims to introduce the ecology of shallow lakes to graduate students. There will be a brief introduction on what is a shallow lake, and the story of the selected shallow lakes in which different governing mechanisms shape ecological interactions (e.g., nutrient induced changes, water level changes, fish stock management, miscellaneous cases). The course will cover the abiotic environment including underwater light climate, sedimention and resuspension, and nutrient dynamics in shallow lakes. There will be an emphasis on the factors regulating the phytoplankton biomass and competition between algae and cyanobacteria. Trophic cascades, which are the most important factors in shallow lakes ecology, will be thoroughly discussed through top-down control of phytoplankton, the effects of planktivorous and piscivorous fish, and benthic connections. A special emphasis will be given to vegetation in shallow lakes since macrophytes play a key role in determining water clarity and animal community. The managing of eutrophicated shallow lakes for restoration will be reviewed as from an applied point of view.

Reference Books

• Ecology of Shallow Lakes.
  1997
  Marten Scheffer.
  Chapman Hall (available at the library)
• The restoration of shallows lakes from eutrophication- a guide.
  1996.
  B. Moss, Jane Madgwick and G. Phillips.
  National Rivers Authority.
• The appropriate recent papers on the selected topics

Objectives

Traditionally, limnology is mostly concerned with deep stratifying lakes, however, shallow lakes are much more numerous and are ultimately much more important both for people and wildlife. Such wetland lakes are of immense importance due to complex ecological structure and high productivity supporting the bulk of biodiversity. Their usual location on the flatter, farmable lowlands, makes shallow lakes more vulnerable and they have become turbid during this century due to eutrophication. The response of shallow lakes to eutrophication is often catastrophic rather than smooth by complete loss of submerged plants, which are the most essential component of a pristine state of such lake. This course aims at bringing better insight into governing mechanisms of shallow lakes at pristine state, and alterations caused by eutrophication in food-web of shallow lakes. The focus is on the practical control of eutrophication of shallow lakes that attempts to bring existing knowledge and experiences together in a form of widespread use.

Outline

1. Introduction (1)
   1. What is a shallow lake
   2. Management problems
2. The story of some shallow lakes (4)
   1. Nutrient induced changes:Veluwemeer and Alderfen Broad
   2. Water level changes:Tamnaren and Rice Lake
   3. Fish stock Management: Zwemlust and Linford Lakes
   4. Storm effects: Lake Ellesmere and Lake Apopka
   5. Miscellaneous cases
3. The abiotic environments (5)
   1. Light under water
   2. Sedimentation and resuspension
   3. Nutrient dynamics
4. Phytoplankton (5)
   1. The regulation of algal biomass
   2. Competition between algae and cyanobacteria
   3. Multi-species competition and succession
5. Trophic cascades (10)
   1. Top-down control of phytoplankton
   2. The effect of planktivorous fish
   3. Seasonal dynamics of plankton and fish
   4. The benthic connection
   5. Piscivorous fish
   6. General patterns
6. Vegetation (6)
   1. Implication of vegetation for animal community
   2. Effect of vegetation on water turbidity
   3. The regulation of vegetation abundance
   4. Vegetation and phytoplankton dominance
7. Managing the ecosystem (6)
   1. Implication of alternative stable states
   2. Nutrient management
   3. Biomanipulation
   4. Hydrological adjustments
   5. Other measures
   6. Selecting restoration measures
8. The limits of knowledge (1)

the figures in parenthesis indicate the number of hours that the topics will be covered.

Justification

In Turkey, over 1.000.000 ha of wetlands or shallow lakes have been irreversibly lost during 20th century, mainly since 1960 for land reclamation, flood control, irrigaiton. The threats of draining, irrigation, and others on the remaining wetland lakes are not as important as in the past owing to realisation of the values of such ecosystems. However, nowadays such ecosystems suffer from deterioation of water clarity due to intensive crop and animal farming, and human untreated sewage effluent dischage. Eutrophication of Turkish shallow lakes is the most important problem that is largely impairing efficient use of them including domestic water supply, decreased fishery, wildlife loss etc. There is a growing need of experienced staff who are knowleged of dynamics of shallow lakes and eutrophication problem of them in Turkey. This course will also be a part of the graduate freshwater ecology studies which aim at elaborating the current status of Turkish lakes and producing restoration measures. Therefore, this course is essential in meeting the demand explained above.