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Preserving Aquatic Biodiversity

Preserving Aquatic Biodiversity. Chapter 12. Lake Victoria. The second largest freshwater lake in the world How have humans changed it? Introduced Nile perch – killed other fish Added nutrients – eutrophication Introduce water hyacinth – blocks light. Aquatic biodiversity.

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Preserving Aquatic Biodiversity

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  1. Preserving Aquatic Biodiversity Chapter 12

  2. Lake Victoria • The second largest freshwater lake in the world • How have humans changed it? • Introduced Nile perch – killed other fish • Added nutrients – eutrophication • Introduce water hyacinth – blocks light

  3. Aquatic biodiversity • Greatest marine diversity in coral reefs and deep-sea floor • Higher near coasts than open ocean • Higher in benthic layer than near the surface • Higher near tropics

  4. How do humans benefit • Food • Seaweed (cosmetics) • Chemicals • Antibiotics • Anticancer • Hypertension • Bone replacement

  5. Destroying freshwater habitats • Draining wetlands – lost over 50 % of wetlands • Introduction of non-native species • Dams, diversions, canals, flood control levees • Ruin existing habitat or changing flow rate, sediment deposits, spawning beds, migration patterns, plant life, nutrient cycles

  6. Major loss of aquatic biodiversity by humans • Overfishing • Habitat destruction • Coastal development • Rising sea level • Trawler boats • Pollution • Introduction of alien species

  7. Nonnative examples • Asian swamp eel – Florida, eats everything, can breath air, cross to new waterways • Purple loosestrife – wetlands, perennial plant in Eurasia, spreads rapidly, no native predators, displaces native plants, reduces biodiversity • Zebra mussels – Great Lakes, from ship ballasts, no natural predators, displaced other mussels, interrupted food chain, clogged pipes, grows in large masses on everything

  8. Major pollution threats • Oil – especially from runoff • Acid deposition • Plant nutrients and oxygen demanding wastes • Toxic chemicals • Sedimentation from development

  9. Protection of Marine Species • CITES • 1979 Global Treaty on Migratory Species • U.S. Marine Mammal Protection Act of 1972 • Endangered Species Act 1973 • Whale conservation and protection act 1976 • Changing fishing nets and fishing practice

  10. Whaling • International Convention for the Regulation of Whaling formed the IWC to set quotas (often ignored) • IWC set moratorium on commercial whaling since 1986 (Inuits still allowed to hunt whale) many populations recovered • US banned whaling and importing goods • Japan and Norway still are large whaling countries

  11. Restoring Wetlands • US requires a federal permit to drain/alter a wetland over 3 acres • Mitigation banking – allows development of wetlands if an equal area elsewhere is created or restored • Use proper planning to keep development/Ag away • Prevent introduction of alien species

  12. Florida’s Mistake • Army Corps of Engineers diverted much of the Everglade’s natural flow with levees and canals • Wetlands dried and were converted to farmland • Runoff from fields introduced excess nutrients • Disrupted entire ecosystem • Now largest ecological restoration project (at least $7.8 billion)

  13. Columbia River Basin • Located in Pacific Northwest – 1,200 miles of river • Largest hydroelectric power system • Provides jobs, electricity, flood control, stimulate industry/agriculture • Hurts habitats especially migratory fish (salmon) • Northwest Power Act 1980 – find way to generate power and rebuild wild salmon and other fish populations

  14. Protecting Rivers • National Wild and Scenic Rivers Act 1968 – waterways kept free from development, no motors, no alterations • A river can be designated by congress based on outstanding scenic, recreational, geological, wildlife, historical, or cultural value

  15. The Great Lakes • Faces several threats • Alien species, like the zebra mussel, is the greatest, but also is encountering • Thermal pollution from power plants • Commercial fishing • Human sewage (mostly processed) • Acid rain (but there is more to the east)

  16. Act Now • Approximately 50% of the world’s original coastal wetlands have been lost • Main reasons • Agriculture • Housing/building development

  17. Commercial fishing techniques • While many systems are bad for the environment, these appear to be the worst • Trawling - nets destroy ocean floor habitat • Drift nets (more than 2 miles long) - kill many mammals, turtles and birds • Longlining - creates a lot of bycatch such as dolphin, shark, pilot whales, birds, and turtles

  18. What can you do? • Use comsumer power to buy products that do not threaten aquatic species • Use environmentally friendly cleaners in the home • Prevent soil erosion • Vote against wetland development • Eat less fish and seafood (more organic veggies)

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