1. Chapter 20
Oceans in Jeopardy
© 2006 Thomson-Brooks Cole

2. 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…
© 2006 Thomson-Brooks Cole

3. 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…
© 2006 Thomson-Brooks Cole

4. 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…
© 2006 Thomson-Brooks Cole

5. Pollution Ocean dumping Ocean as dumping site for trash & garbage
17th annual Coastal Cleanup in September 2002 cleaned 5,148 miles of U.S. coastlines
2.8 million lbs. 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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7. Pollution Ocean dumping plastic
strength and durability of plastic make it one of the most hazardous materials in the sea
Remains in marine environment for a long time
marine animals and plastic
Discarded/lost traps ensnare animals (die of starvation)
Suffocated by plastic bags & sheets of plastic
Ingested plastics form an indigestible mass blocking digestive tract leading to starvation…
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9. Pollution Ocean dumping
Controlling plastic – Marine Plastic Pollution Research and Control Act of 1987
Prohibits dumping of plastic in ocean
Requires ports & terminals to provide facilities for disposal of this waste
US Navy can still legally dump trash & plastic in the ocean
Enforced by the Coast Guard
International agreement prohibits dumping of plastic in ocean
Trouble with enforcement
© 2006 Thomson-Brooks Cole

10. Pollution Commercial dumping
Example: garbage, sewage and toxic chemicals have been dumped into the New York Bight (near mouth of Hudson River) since 1890
1.4 million cubic meters of solid waste dumped between 1890 and 1971
EPA closed offshore dump in 1987…
© 2006 Thomson-Brooks Cole

11. Pollution Ocean dumping military refuse
discarded military hardware and munitions following major wars
For example after WWII:
toxic gases and chemicals from Germany in Atlantic
Jeeps, tanks, trucks, and munitions in Pacific
Waste can entangle or poison marine birds or mammals
Metallic waste can also be converted into artificial reefs
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12. Pollution radioactive wastes
disposal of radioactive materials in subduction zones has been proposed
Wastes ultimately be taken into the mantle eliminating need for long term storage
currently, this is prohibited by the Ocean Dumping Act of 1972, which requires an environmental impact statement and approval of the House and Senate…
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13. Pollution Pollution via land and air Urban pollution
Major population centers along coastline (estuaries and rivers that drain into them)
Need 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, etc…
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14. Pollutants carried into the sea by rivers and washed into the sea by rainwater and melting snow.
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15. Pollution Pesticides and toxic materials from industry
Pesticides (e.g. DDT), toxic organic compounds (e.g. PCBs), heavy metals (e.g. mercury, lead, & zinc)
Continue to enter the sea through runoff from land even though banned
DDT banned in 1960s; 1-7% of another pesticide (dicofol) used until 1988
DDT exposure linked to cancer & threat to birds (thin shelled eggs)
PCBs also have possible cancer link, liver disease, immune effects, & impaired cognitive development
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16. Pollution Biological magnification
Concentration of toxins in the tissues of animals increases as they are passed up the food chain without being broken down or excreted
Eventually concentration of toxin or chemical will be high enough to cause serious illness or death
Effects of toxic compounds on plankton
Toxic pollutants inhibit photosynthesis, growth, and cell division
Could lead to a reduction in marine primary productivity…
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17. Biological Magnification: Toxins accumulate in tissues of consumers
Biological Magnification: Toxins accumulate in tissues of consumers. Toxins are not broken down or excreted by organisms. Ultimately the toxin will reach a deadly level in a higher order consumer.
© 2006 Thomson-Brooks Cole

18. Pollution Air pollution
sulfur dioxide from burning of fossil fuels can precipitate in water and lower pH of seawater
greenhouse gases (e.g. CO2, methane) contribute to global warming
Coral bleaching (loss of color of corals, due to stress-induced expulsion of symbiotic unicellular algae or due to the loss of pigmentation within the algae)
Melting of glaciers & polar ice
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19. Pollution Nutrient pollution Human wastes
Reduce water quality by adding harmful microorganisms & nutrient enrichment
Disease agents
Filter feeders (clams, mussels, etc) can concentrate microbes (hepatitis virus and Salmonella bacteria) in tissue; cause diseases if eaten
coliform bacteria, found in the intestines of many animals, are counted to monitor water quality (amount of animal waste entering water)
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20. Pollution
Eutrophication: increase in amount of dissolved nutrients in water
– leads to blooms of phytoplankton and other marine microbes
Interfere with primary productivity at greater depths; excessive decomposition after death leads to oxygen depletion & affects respiration for other organisms
Increased productivity
It has been observed that sometimes the addition of sewage and animal wastes can boost the productivity of a marine community…
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21. Pollution Nutrient pollution (continued) agricultural wastes
fertilizers and animal wastes have effects similar to those of human wastes
Eutrophication and addition of disease causing microbes
Agricultural nutrients carried by Mississippi River to Gulf of Mexico caused hypoxic zone (water with abnormally low oxygen content)
pesticides are also found in runoff from farms
Can poison the water…
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22. Hypoxic Zone: Agricultural nutrients draining into the Gulf of Mexico have contributed to the depletion of oxygen in an area off Louisiana referred to as the “dead zone.”
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23. 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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24. Petroleum Pollution Petroleum products
crude oil contains 2 major types of organic molecules: aromatic hydrocarbons and aliphatic hydrocarbons
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25. Aromatic hydrocarbons: molecules made up of carbon atoms in ring structures
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26. Petroleum Pollution aliphatic hydrocarbon:straight-chain molecules.
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27. Petroleum Pollution
Petroleum products are persistent, difficult for microbes to degrade, and toxic to organisms
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
10 million gallons of oil into Prince William Sound
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28. Petroleum Pollution Ecological effects of oil spills
Effects on birds and mammals
Impairs ability of bird to fly or swim
Impairs ability of feathers to insulate; possible hypothermia
Birds may ingest fatal amounts oil when cleaning
In otters destroys the ability of the fur to insulate leading to hypothermia
Clogs nostrils & eyes
Possible cancer link
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29. Petroleum Pollution Effects on invertebrates and algae
Invertebrates on sandy shore killed by toxic oil components or smothered
Flesh of intertidal invertebrates becomes tainted & is passed along food chain
Community effects: decrease in species diversity in intertidal zone & simplification of the food web…
© 2006 Thomson-Brooks Cole

30. Petroleum Pollution 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
Current legislation prevents use of this type of organism in nature
Materials such as feathers used to be commonly used.
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32. Oil kills molluscs, allowing seaweeds to overgrow the intertidal rocks.
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33. 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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34. 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 currents—generated by waves that break at an angle to the beach, moving parallel to the beach
longshore transport process—transport of sediments by longshore currents
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38. 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 sea’s resources without jeopardizing its environmental or economic value for the future
© 2006 Thomson-Brooks Cole