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

Freshwater Ecosystems Stream / River Pond / Lake Wetland

Planet Earth: Freshwater http://www.cornel1801.com/bbc/PLANET_EARTH/Freshwater_online_documentary_film.html 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

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)

Phytoplankton

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

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

Pond or Lake

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

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

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

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

Eutrophication

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