Environmental Problems

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Environmental Problems

• Global Warming
• Pollution
• Overfishing

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Global Warming Causes

• Green house effect
• Green house gases (chloroflourocarbons CFCs,
  methane, CO2, water vapor)
• Increasing CO2
• Deforestation burning fossil fuels

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Fig. 15-31, p. 326
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Global Avg Surface Temp Relative to 1951-80 mean
Fig. 15-32, p. 326
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Global WarmingMarine Impacts
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The North Pole 1996
Fig. 15-33, p. 327
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The Maldives in the Indian Ocean 80 pop. live
only 1m above sea level
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Global WarmingMarine Impacts

• Sea-level Rise (4-10 inches last century)
• Coastal habitats, corals
• Coral Bleaching
• Habitat shifts
• Fresh water lens
• Circulation patterns

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Marine Pollution

• The introduction into the ocean by humans,
  substances that changes the physical, chemical or
  biological environment

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Marine Pollution

• Many forms
• chemicals, sewage, solid waste, sediment, heat
• Impact of a pollutant depends on quantity,
  toxicity of the pollutant to each organism, its
  affect on the environment
• Bioamplification even small amounts of
  pollutants can have large effects

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Rachel Carson Silent Spring 1962 misuse of
pesticides
Fig. 15-23, p. 321
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PCBs Poly chlorinated Biphenyls

• used in hundreds of industrial and commercial
  applications
• (including electrical, heat transfer, and
  hydraulic equipment as plasticizers in paints,
  plastics and rubber products in pigments, dyes
  and carbonless copy paper and many other
  applications)
• More than 1.5 billion pounds of PCBs were
  manufactured in the U.S. prior to cessation of
  production in 1977.
• 1976 the Toxic Substances Control Act (TSCA) that
  included prohibitions on the manufacture,
  processing, and distribution in commerce of PCBs.

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Marine Pollution

• Eutrophication
• Excess nutrients in water also lead to problems
• HABs
• Oxygen depletion

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Fig. 15-22, p. 321
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Overfishing

• When so many fish have been harvested, there are
  not enough left to breed and replenish the
  species
• 45 fish stocks known are overfished

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Overfishing

• When so many fish have been harvested, there are
  not enough left to breed and replenish the
  species
• 45 fish stocks known are overfished

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Fig. 15-10, p. 311
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Overfishing Causes

• Hard to estimate maximum sustainable yield
• Must know pop. size, growth reproduction, life
  span
• Models are oversimplified
• Dont always consider competition, schooling
  behavior, size of fish caught, when they are
  caught

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Bykill or By-catch

• Other species are accidentally caught
• Drift nets banned in 1993
• Dolphin-Safe Tuna
• Turtle exclusion devises (TEDs)

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Fig. 15-7a, p. 309
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Fig. 15-7b, p. 309
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Fig. 15-26, p. 323
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What Can Be Done?

• Education
• Rational activism even at the individual level

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Ozone Depletion Causes

• Ozone three atoms of oxygen
• Forms naturally in upper atmosphere
• CFCs attack deplete ozone layer
• 4 decrease in US since 1969
• 50 decrease over poles

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Ozone Depletion Marine Impacts

• Increasing UV levels
• Decrease in phytoplankton productivity
• Mortality of surface zooplankton (larvae)

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Fig. 15-29, p. 325