Oceans in Jeopardy

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Chapter 20

• Oceans in Jeopardy

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Key Concepts

• Dumping wastes into coastal seas decreases their
  economic and recreational value and creates
  health hazards.
• Pollutants enter coastal seas by way of
  agricultural and urban runoff as well as by
  direct dumping.
• Some pollutants accumulate and magnify in food
  chains, posing serious problems for higher-order
  consumers.

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Key Concepts

• Plastic trash is deadly to large marine animals.
• Oil spills damage significant amounts of habitat
  and injure and kill marine life.
• Development of coastal areas leads to loss of
  habitat and diminished numbers of marine life.

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Key Concepts

• Destruction of wetlands results in decreased
  ocean productivity.
• It is not too late to become involved with
  conserving the oceans and their resources.

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Pollution

• Ocean dumping
• trash 17th annual Coastal Cleanup in September
  2002
• 2.8 million lb. of trash and debris in 3 hours
• 1.3 million cigarette butts and filters
• 226,251 glass bottles
• 238,826 metal cans
• 2,529 syringes
• 61 of trash collected was plastic
• 82 animals found trapped in the debris

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Pollution

• Ocean dumping (continued)
• plastic
• strength and durability of plastic make it one of
  the most hazardous materials in the sea
• marine animals and plastic
• controlling plastic Marine Plastic Pollutino
  Research and Control Act of 1987
• commercial dumping
• garbage, sewage and toxic chemicals have been
  dumped into the New York Bight since 1890

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Pollution

• Ocean dumping (continued)
• military refuse
• discarded military hardware and munitions
• toxic gases and chemicals
• radioactive wastes
• disposal of radioactive materials in trench
  subduction zones has been proposed
• currently, this is prohibited by the Ocean
  Dumping Act of 1972, which requires an
  environmental impact statement and approval of
  the Congressional House and Senate

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Pollution

• Pollution via land and air
• urban pollution
• 50 of the U.S. population lives within 50 miles
  of coastline (including the Great Lakes)
• this population needs energy, industry and waste
  treatment
• coastal seas and habitats are polluted by
  associated runoff from land
• pesticides, fertilizers, gasoline, oil, sewage,
  chemicals used to treat sewage
• organic lead entering the sea has been decreased
  by use of unleaded fuels since 1980

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Pollution

• Pollution via land and air (continued)
• pesticides and toxic materials from industry
• pesticides (e.g. DDT), toxic organic compounds
  (e.g. PCBs), heavy metals (e.g. mercury, lead,
  zinc, and chromium)
• biological magnificationconcentration of toxins
  in the tissues of animals as they are passed up
  the food chain without being broken down or
  excreted
• effects of toxic compounds on plankton

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Pollution

• Pollution via land and air (continued)
• air pollution
• sulfur dioxide from burning of fossil fuels can
  precipitate in water and lower pH
• greenhouse gases (e.g. CO2, methane) contribute
  to global warming
• global warning is thought to cause coral
  bleaching, and might raise sea levels, killing
  corals that must remain close to the surface to
  obtain sufficient sunlight for zooxanthellae

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Pollution

• Nutrient pollution
• human wastes
• disease agents
• coliform bacteria, found in the intestines of
  many animals, are counted to monitor water
  quality
• eutrophication leads to blooms of phytoplankton
  and other marine microbes
• increased productivity
• sometimes, the addition of sewage and animal
  wastes can boost the productivity of a marine
  community

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Pollution

• Nutrient pollution (continued)
• agricultural wastes
• fertilizers and animal wastes have effects
  similar to those of human wastes
• pesticides are also found in runoff from farms

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Pollution

• Controlling pollution
• legislation was passed to prohibit dumping of
  sewage sludge or industrial wastes in the ocean
  after Jan. 1, 1992
• largest threat is increasing coastal populations
  and improperly controlled commercial and
  residential development

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Pollution

• Petroleum pollution
• petroleum products
• crude oil contains aromatic hydrocarbons and
  aliphatic hydrocarbons
• aromatic hydrocarbonsmolecules made up of carbon
  atoms in ring structures (e.g. benzene,
  naphthalen, cyclohexane)

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Pollution

• Petroleum pollution
• petroleum products
• aliphatic hydrocarbonsstraight-chain molecules
  (e.g. heptane, octane, nonane)
• petroleum products are persistent, difficult for
  microbes to degrade, and toxic to organisms

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Pollution

• Petroleum pollution (continued)
• oil spills
• largest oil spill in the U.S. was in March 1989,
  when the tanker Exxon Valdez ran onto a rocky
  reef 25 miles from Valdez, Alaska
• largest and longest-lasting oil spill ever was in
  June 1979, when an offshore oil well in the Gulf
  of Mexico, the Ixtoc 1, blew out and caught fire
• oil spills are deadly for marine organisms

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Pollution

• Petroleum pollution (continued)
• ecological effects of oil spills
• effects on birds and mammals
• effects on invertebrates and algae
• community effects

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Pollution

• Petroleum pollution (continued)
• oil spill cleanup
• oil booms and oil skimmers help to confine the
  spill to a smaller area and recover some of the
  oil
• straw is used to soak up the oil, then burned
• a bacterium genetically engineered to degrade
  crude oil is being tested

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Habitat Destruction

• Wetlands
• provide nutrients, shelter and spawning grounds
  for a variety of marine organisms
• have been drained, filled or dredged to provide
  more ground for industry, channels into
  ports/harbors, and beach-front real estate
• legislation now protects wetlands, but the
  government continually changes the definition of
  wetlands

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Habitat Destruction

• Beaches
• direct effects of beach use and development on
  marine life
• disturbs nesting sites of birds, sea turtles and
  horseshoe crabs
• destruction of habitat
• interfering with natural processes
• longshore currentsgenerated by waves that break
  at an angle to the beach, moving parallel to the
  beach
• longshore transport processtransport of
  sediments by longshore currents

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Epilogue

• Natural changes are small and occur over long
  periods of time
• Changes caused by humans can be instantaneous and
  involve entire marine communities
• Understanding the underlying patterns and
  processes of the sea allows people to use the
  seas resources without jeopardizing its
  environmental or economic value for the future