1. Aquatic Ecosystems Objectives:
Describe the characteristics of fresh water ecosystems.
Describe a lake, pond, wetland, marsh, river and swamp.
Describe human impacts on each of the above ecosystems

2. Freshwater Ecosystems
Stream / River
Pond / Lake
Wetland

3. Planet Earth: Freshwater
Part 1 : 0 – 7:38
Part 2 : 0 – 2:48
6:07 – 9:38
10:38 – 12:32
Part 3 : 1:45 – 9:30
10:35 – 12:01
Part 4 : 0 – 3:22
4:27 - end

4. Fresh Water Ecosystems
Only 3% of the Earth’s water is fresh
Organisms living in fresh water are grouped by their location
1.Plankton – drifting microscopic plants and animals (phytoplankton are basis of food chain)

5. Phytoplankton

6. Freshwater Ecosystems
2. Nekton – free-swimming organisms like fish, turtles and whales

7. Freshwater Ecosystems
3. Benthos – bottom-dwelling organisms such as mussels, worms, barnacles

8. Pond or Lake

9. Pond or Lake
Littoral Zone – shallow water closest to shore, photosynthesis happens here
Limnetic Zone – layer of open water, nekton swim here, photosynthesis happens here
Profundal Zone – deeper, cold, dark water where light does not penetrate, nekton swim here
Benthic Zone – bottom, deep, cold, dark ground where decomposers are

10. Wetlands
Trap and filter sediments, nutrients and pollutants, keeping them from entering reservoirs
Reduce the likelihood of flooding
Buffer shorelines against erosion
Provide habitat for commercial important fish and shellfish
Provide habitat for rare and threatened species
Provide recreation

11. Wetlands Human Impacts Residential and Commercial Development
6 million acres of the Everglades in South Florida were drained and filled for building
Pg 206
Pg 207

12. Pond or Lake Human Impacts
Eutrophication – an increase in the amount of nutrients (phosphates and nitrates) in an aquatic ecosystem caused by sewage, fertilizers or animal waste
Causes an excessive amount of algal growth and decay (algal bloom)
The algal bloom can produce toxins that kill animals
Causes a decreased level of oxygen which kills animals

13. Eutrophication

14. Eutrophication - Prevention and Reversal
Oyster reefs filter out extra nutrients
Laws regulating the discharge of sewage
Educating farmers on fertilizer use