Aquatic Ecosystems

1
Aquatic Ecosystems

• Jennifer K. Meyer
• Sr. Plant Environmental Coordinator
• American Electric Power

2
Freshwater Ecosystems

• Only 3 of the worlds water is fresh, and 99 of
  this is either frozen in glaciers and pack ice or
  is buried in aquifers. The remainder is found in
  lakes, ponds, rivers and streams.

3
Limnology

• The study of freshwater ecosystems, with an
  emphasis on understanding the physical, chemical
  and biological processes that are important in
  structuring and maintaining freshwater systems.

4
Science of Limnology embraces

• Lakes (Lentic waters)
• Rivers (Lotic waters)
• Estuaries
• Other microhabitats such as springs and streams

5
Lakes vs. Reservoirs

• Lakes Natural

• Reservoirs Man made

6
Physical Aspects

• Light, heat, waves, and currents can produce
  physically distinct zones that can vary by day
  and season.

7
Physical - Zonation

• Littoral Zone extends from the shore to just
  above the influence of waves to a depth where the
  light is barely sufficient for rooted aquatic
  plants to grow

8
Physical - Zonation

• Limnetic Zone area beyond the influence of the
  shore or bottom (pelagic).

9
Physical - Zonation

• Profundal Zone many lakes (but few ponds) are
  so deep that not enough light reaches here to
  support productivity.

10
Physical - Temperature

• Thermal Stratification
• Epilimnion upper warmer water of a stratified
  lake (less dense)
• Thermocline middle portion where the rate of
  temperature change is greatest
• Hypolimnion deeper colder water of a stratified
  lake (more dense)

11
Physical Temperature
12
Physical Temperature

• Fall Overturn
• less solar radiation reaches the water
• greater heat loss at night
• winds begin to erode the thermocline
• The epilimnion increases in depth as it decreases
  in temperature.
• Eventually the temperature and density difference
  between the overlying water and that beneath is
  so slight that a strong wind in late autumn
  overcomes the remaining resistance to mixing and
  the lake turns over.

13
Physical - Temperature

• Spring Overturn In spring the lake ice melts,
  the wind mixes the cold water, and the surface
  temperature increases enough for thermal
  stratification to be reestablished.

14
Chemical Structure

• Greatest cause of altered water chemistry in
  natural waters is now pollution from human waste,
  agriculture and industry.
• Without proper control, the increased chemical
  loading can lead to eutrophication of lakes and
  reservoirs.

15
Chemical Structure

• Chemical composition of natural aquatic
  ecosystems are dependent on rainfall, erosion,
  evaporation and sedimentation.
• Water contains a vast array of inorganic and
  organic compounds which are present as dissolved
  solids and gases.

16
Biological Structure

• Viruses role usually associated with public
  health problems (i.e. hepatitis can be
  transmitted by ingestion of natural waters
  contaminated with the feces of infected people

17
Biological Structure

• Bacteria unicellular organisms responsible for
  recycling of organic and inorganic materials.

18
Biological Structure

• Fungi participate in the decomposition and
  recycling of vegetable and animal matter.
• Phytoplankton - algae may be unicellular,
  colonial or filamentous in form (Pediastrum)

19
Biological Structure

• Macrophytes aquatic plants may dominate
  shallow lakes and streams.
• Zooplankton components are protozoans, rotifers
  and crustaceans.

20
Biological Structure

• Zoobenthos bottom feeders includes insect
  larvae, crustaceans and mollusks.
• Fish

21
Aquatic Ecology Application

• Compliance with water quality standards and
  permits
• Fish population and bioaccumulation studies

22
Aquatic Ecology Application

• Biomonitoring studies for toxicity of effluent

23
Aquatic Ecology Opportunities For The Classroom

• Pond Life Microscopic and Macroscopic
• Water Testing

• Wetland Scavenger Hunts and Surveys

24
Aquatic Ecology Opportunities For The Classroom

• Fishing Techniques

• Fish Identification and Dissection

25
AEP is committed to protecting and enhancing
the quality of the environment as we conduct our
business worldwide.