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Preserving Aquatic Biodiversity


Preserving Aquatic Biodiversity Chapter 12 – PowerPoint PPT presentation

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Title: 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
  • 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

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

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

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

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

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

Protection of Marine Species
  • 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

  • International Convention for the Regulation of
    Whaling formed the IWC to set quotas (often
  • 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

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
  • Use proper planning to keep development/Ag away
  • Prevent introduction of alien species

Floridas Mistake
  • Army Corps of Engineers diverted much of the
    Everglades 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)

Columbia River Basin
  • Located in Pacific Northwest 1,200 miles of
  • 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

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

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)

Act Now
  • Approximately 50 of the worlds original coastal
    wetlands have been lost
  • Main reasons
  • Agriculture
  • Housing/building development

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

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)