Chapter Seven: Aquatic Ecosystems

Section One: Freshwater Ecosystems Lakes Ponds Rivers Streams Wetlands: where land is periodically under water

Section One: Freshwater Ecosystems Characteristics of Aquatic Ecosystems Temperature, Sunlight, Oxygen and Nutrients Plankton: organisms that cannot swim against currents so they are drifters Nekton: free swimming organisms Benthos: bottom dwelling organisms

Section One: Freshwater Ecosystems Lakes and Ponds Littoral Zone: nutrient rich zone near the shore Phytoplankton, ducks, reeds Benthic Zone: bottom of a pond or lake Decomposers, insect larvae, clams

Section One: Freshwater Ecosystems

Section One: Freshwater Ecosystems How Nutrients Affect Lakes Eutrophication: an increase in the amount of nutrients in an aquatic ecosystem Happens naturally but can be sped up by runoff

Section One: Freshwater Ecosystems Freshwater wetlands Swamps and marshes Absorb and remove pollutants from the water Control flooding Spawning of freshwater fish Home for native and migratory wildlife

Section One: Freshwater Ecosystems Marshes Low flat lands, with little water movement Benthic zones are nutrient rich Salinity varies Swamps Occur on flat poorly drained land, often near streams Reptiles are predators

Section One: Freshwater Ecosystems Human Impact on Wetlands Many were drained because they were considered breeding grounds for insects Purifiers of wastewater Flood prevention

Section One: Freshwater Ecosystems Rivers Mosses are found on rocks near the headwaters Animals are adapted to the cold oxygen-rich waters Communities and industries affect the health of rivers

Section Two: Marine Ecosystems Coastal Wetlands Estuaries Salt Marshes Mangrove Swamps

Section Two: Marine Ecosystems Estuaries An area in which fresh water from a river mixes with salt water from the ocean Serves as a nutrient trap Mineral rich mud and dissolved nutrients fall to the bottom and become available for producers.

Section Two: Marine Ecosystems Estuaries Plants and Animals Manatees, Horseshoe crabs, dolphins, otters, oysters Able to tolerate variations in salinity Threats Used as landfills Pollutants such as runoff and sewage

Section Two: Marine Ecosystems Salt Marshes In estuaries where rivers deposit their mineral rich mud Acts as a nursery for shrimp, crabs, and fish Absorb pollutants and protect inland areas

Section Two: Marine Ecosystems Mangrove Swamps Dense growth of mangrove trees in swampy areas Protect the coastline from erosion

Section Two: Marine Ecosystems Rocky and Sandy Shores Have more plant and animal species than sandy shores Barrier islands: run parallel to sandy shores

Section Two: Marine Ecosystems Coral Reefs Limestone ridges built by tiny coral animals called coral polyps Found in shallow tropical seas where light is plentiful for photosynthesis Serve as a habitat for many organisms

Section Two: Marine Ecosystems Coral Reefs Very fragile Susceptible to extreme hot or cold and high nutrients Coral bleaching: when coral turns white and can die 50% of of the world’s coral reefs in danger

Section Two: Marine Ecosystems Oceans Much of ocean life concentrated in shallow coastal waters Plants and Animals Phytoplankton and zooplankton

Section Two: Marine Ecosystems Oceans Threats Pollution Overfishing and certain fishing methods Arctic and Antarctic Arctic is rich in nutrients from surrounding land masses Antarctic is the only continent not colonized by humans