MARINA POLLUTIONA
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- major pollutants and their sources
- nutrients, dediments, pathogens, oil, persistent cources, plastic sources, radiotive isotopes, thermal , aliean species, noise!
- sediment
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sources: forestry, erosion, construction, dredging
effects: increases in turbidity, smothers reefs, clogs fish - nutrients*
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sources: runoff, agriculture, forestry, sewage, industry (not as big)
effects: eutrophications, phase-shift, dead zones, algae blooms - pathogens
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sources: sewage, livestock
effects: disease - persistent toxins
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sources: DDT, PCBS, Industry, landfills, agro
effects: toxic, food webs, bioaccumulation - plastics*
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sources: Fishing nets, garbage from cargo and cruise ships, beach litter, industry, landfills.
effects: Can entrap marine life or be ingested. May persist for 400 years! NOT EASILY BROKEN DOWN - radioactive isotopes
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CAUSES: Illegal dumping, medical waste, military accidents, nuclear weapons testing.
EFFECTS: Carcinogenic and persistent for thousands of years. - thermal
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CAUSES: power plants
EFFECTS: Alters coastal ecosystems. - noise
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CAUSES: Shipping, navy sonar testing.
EFFECTS: arguably disrupts marine life (whales who use sonar) - alien species (ballast water)
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CAUSES: Ballast water of ships, canals, aquaculture.
EFFECTS: Out compete native species; reduce marine biodiversity, new diseases. - land-based sources*
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Land-based sources account for 77% of marine pollution and are the most difficult to control.
33% airborne emissions from land (cars, industry, incineration)
44% run-off in rivers and streams - point/non-point sources*
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A point source has a clearly identifiable origin (e.g. the discharge from a specific factory) and is easier to identify and regulate.
Non-point sources come from wide areas (e.g. pesticide run-off from an agricultural area, storm drains in a residential area) and are more difficult to identify and regulate. - Torrey Canyon Spill (1967)
- The first really big oil spill to mobilize international prevention efforts was the Torrey Canyon in 1967 off the coast of Cornwall (120,000 tonnes spilled).
- Exxon Valdez spill (1989)
- led to the US Oil Pollution Prevention Act of 1990. A key provision of this law is to require all tankers operating in US waters to have double hulls by 2015; and all single hull tankers older than 23 years to be phased out by 2005. [See Box 11.1 in textbook]
- Prestige spill (2002)
- (coast of Spain 2002) led the IMO to adopt an accelerated phase-out schedule for single-hull tankers, requiring ships constructed before 1984 to be replaced by 2010.
- double-hull tankers*
- controversy over double-hulls as some shipping companies may maintain double hulls less because of cost