Gulf Oil Spill - Team Analyzers

ESS Model Building

Event - Atmosphere

  • Plumes of smoke will cause particles and gases to enter the atmosphere
  • The materials can combine with air particles to spread throughout the atmosphere
  • E > A > B Toxic smoke enters air from burning of large areas of oil on water
  • E > A > B Explosion of Platform starts fire on water, kills workers
  • short term, during the spill when oil and gas was burned off, carbon dioxide was released into the atmosphere along with smoke and dust particles (pollution, condensation nuclei) and causing rain downwind E>A>H
  • longer term effects of the fumes from the oil (methane etc) seeping into the atmosphere
    • >B unhealthy conditions for organisms
    • >H polluted water evaporating and entering the water cycle

Event - Lithosphere

  • Drilling oil out of the ground can cause the lithosphere to be disturbed
  • Drilling can cause earthquakes or change the landscape
  • destruction of wetlands, reduces land available on coasts
  • oil seeping into sand
    • > Biosphere as ducks and other organisms dig in the oil soaked sand for food
    • >B as tourists don't want to go on that sand > B business relying on tourist trade
  • E > L > B Oil covers wetlands and wildlife, destroying plants, habitats, coating sea birds in oil, birds ingest oil and die
  • E > L > B Soil polluted with oil, unable to sustain plant life
  • E>L>B river sediments have built the Mississippi Delta, the largest coastal wetland in the lower 48 states - oil destroying this area would  be destroying a lot of living space

Event - Hydrosphere

  • Millions of gallons of crude oil can pollute the water and contaminate drinking water
  • oil disrupts evaporation of sea water and water cycle
  • E > H > A > B Oil layered on water blocks sunlight, decreases transpiration, blocking wildlife access to ocean's surface
  • oil makes water less able to dissolve oxygen
    • >B organisms cannot survive in the water, dead organisms sink to bottom of gulf, in large numbers, decomposing microbes cannot decompose the dead organisms fast enough, producing stagnant waters
  • dark color of the ocean affects absorbing heat from the sun - more likely to absorb more heat, increase temperature of water
    • >B warmer water, less able to absorb oxygen, further reduces chances of surviving for organisms
  •  Oil enters fresh water estuaries, wetlands
    • approximately 60% of the US watershed drains into the Gulf of Mexico

Event - Biosphere

  • Animals can be covered in oil
  • Food from the ocean becomes contaminated
  • Crops and plants are endangered
  • Humans can't fish or swim in the area, economies dependent on fishing and tourism destroyed
    • is farm land affected too as water cycle affected by oil? >H
  • Clean-up is extremely time consuming and expensive
  • Animal habitats and food chains are destroyed
  • large marine mammals killed by ingesting or inhaling oil
    • The Gulf houses one of the world's highest concentrations of turtle species, 5 of which are threatened or endangered
      • Kemp's Ripley sea turtles are an endangered species that only live in the Gulf, many have been found dead - if the species is eradicated by the oil irreparable damage will have been don to biodiversity in the world
      • lifecycle of turtles disrupted at every stage by oil, from egg to adult
  • destruction of wetlands (saltwater marshes)
    • > H > L > B, A marsh grasses filter pollutants so if the grasses die the waters will lose this pathway to pollution reduction, also the marsh grasses trap sediment which helps build land, so without the marshes the coastline will recede, which will mean less land for living on in the future and less oxygen in the atmposhere as the grasses no longer are photosynthesizing
  • shoreline forests damaged
    • pine savannas, live oak - if damaged by oil in soil, then the protection the forests provide from hurricanes will be lost which will result in greater damage from hurricanes in the future, including more destruction of the coastline and its habitats A (hurricanes) > B > L
    • migratory birds rest in the forests and feed before crossing the gulf, if the forests decline fewer will be able to make the journey safely
  • Mangrove forests with tangled roots in the water susceptible to damage from oil in the water
    • would result in loss of hiding places for young sport fish (gray snapper, red drum), could lead to rapid declines in populations as sport fishermen likely to catch them
  • fishing, crabbing, shrimping businesses affected
    • massive unemployment in fishing economy, loss of income
  • tourist activities decrease, economic losses for businesses dependent on tourists
  • massive unemployment of oil workers as oil rigs shut down/not built
  • layers of life in Gulf of Mexico from bottom to top - damaged beyond ability to recover in finite amount of time
    • livelihoods destroyed
    • sources of food destroyed
    • ecosystems destroyed
  • phytoplankton in bright surface layer of water small and vulnerable to oil on the surface which prevents sunlight reaching the phytoplankton as well as surrounding it and preventing it from functioning > B many other marine creatures feed on the phytoplankton
    • A, H > B if phytoplankton do not photosynthesize, oxygen will not enter the atmosphere and hydrosphere from this source- which will impact organisms breathing this oxygen depleted air, or living in the less oxygenated water


Problem Statement

(Scenario states: "Prepare to brief a panel of US Government agencies on the long term Earth System consequences of the oil spill to the Gulf Region.")

What are the immediate and future costs of the enormous 2010 oil spill and the subsequent clean-up to the Gulf of Mexico?

Living organisms are affected by oil via the following main pathways:

  • physical contact
    • oil that gets on the skin of animals blocks the pores and makes it difficult for them to breath and move in water
    • coating of fur or feathers
      • interferes with ability of the feathers or fur to resist water so the organisms ability to stay dry is affected which can lead to hypothermia
      • interferes with ability of feathers to trap air and so birds cannot fly or float or dive for food, possibly leading to drowning
    • oil on the surface or in a plume underwater could coat the skin of any organism that floats or swims through it, or lands on it
  • absorption through skin
    • kill slowly via damage to blood, heart and gastrointestinal tract (including cancers)
    • oil on the surface or in a plume underwater could coat the skin of any organism that floats or swims through it, or lands on it
  • inhalation
    • can kill immediately
    • kill slowly via lung damage
    • oil on the surface or in a plume underwater could be inhaled by any organism that takes in that water through the mouth, 
  • ingestion
    • can kill immediately
    • kill slowly via lung, liver, and kidney damage
    • oil on the surface or in a plume underwater could be ingested by organisms floating, swimming or feeding through it
All of these pathways for oil entering the bodies of organisms can lead to long term reproductive issues for the organisms, meaning that populations could be weakened and depleted in the future even if there were few immediate deaths.

We analyzed the possible effects of oil on the layers of life in the Gulf of Mexico.

Dark and Teeming Layer of Gulf of Mexico

The sea floor in the Gulf of Mexico can be as deep as 2 miles. The Macondo Well was 5000 feet below the surface and when a leak developed in April 2010 gas and microscopic oil droplets began gushing out into the cold water at high pressure into a zone of seawater that is home to many organisms. The zone from the deep sea floor up to 3,300 feet is called the bathypelagic zone and many organisms have adapted to life in the dark, cold, high pressure conditions. Organisms found living in this zone before the oil spill included:

  • 20 foot long elbowed squid
  • giant squid
  • bioluminescnet fish
  • deep-sea jellies
  • Cold seep organisms that subsist on the methane and hydrogen sulfide gases seeping out from the sea-floor naturally and by catching coral and organic matter drifting or swimming past include:
    • mussels
    • tubeworms
    • caridean shrimps
    • microbes
Any of these organisms in the immediate vicinity of the oil leak could have been killed as they ingested or inhaled the gushing oil droplets and gas. In the dark of this zone, the organisms could have been pushed out of the way by the pressure as the oil gushed out of the well. The pressure on the leaking oil would be forcing the oil upwards and away from the sea floor so the organism may have escaped unharmed. If, however, there is now a layer of oil settled on the sea floor in the deepest regions all of the organisms could be threatened as the oil disrupts life cycles and damages the internal workings oft hose organisms. Handwerk reports conflicting findings by scientists as recently as April 2011, some research suggesting there is no oil on the deep sea floor and some suggesting there is. Certainly a great deal of oil (estimated 4.9 millions barrels) was leaked into the Gulf of Mexico during the spill and not all of it is accounted for by clean up or burn off or natural evaporation. It seems likely that considerable amounts of the heavier oils have settled on the sea floor in some areas.

U.S. Fish and Wildlife Service report "Effects of Oil on Wildlife and Habitat" highlights the impacts on phytoplankton that will be inhaled into whale's baleen, damage algae, fish eggs and invertebrate larvae. Oil is present 30 years after a spill. It sinks into sediments and mud at ocean bottom and will be especially harmful for bottom dwelling lobsters, crabs and tidal pool oysters and clams.

The naturally occurring microbes in the water at these depths that are capable of digesting the gases and oil droplets could flourish in the oil dispersed in the water at depth by the spill and assist in the clean up of the spill. However this process requires the microbes to absorb oxygen from the water. The larger organisms populating the zone would die without oxygen in the water. A long term consequence could be an unbalanced ecosystem in the deep and teeming layer of life, with it teeming with methane digesting microbes and not much else.

Dispersants were employed at the site of the leak in an attempt to prevent oil from reaching the surface. This not only made it very difficult to estimate how much oil was leaking, but resulted in under water plumes of oil droplets and gas that stretched for as far 30 miles from the leak and stayed in the water column for extended periods of time mostly below 3000 feet and potentially affecting the organisms in this region.Organisms that ingested small amounts of oil might not die, but their reproductive health might be adversely affected so that in the future populations might be depleted or weakened or both.

Twilight Zone of Gulf of Mexico

The zone of cold, weakly lit, water just above the dark and teeming zone (3,300 feet -650 feet) is home to snow white Lophelia coral reefs that have been building for thousands of years and which supports more than 2,000 species including:
  • anemones
  • brittle stars
  • urchins
  • chain cut sharks with their fluorescent skins
  • galatheid crabs
  • giant isopids
  • cutlass fish
  • crevalle Jacks
  • squid
This melopalegic zone features predators, scavengers and filter feeders who benefit from the detritus falling from the water above. Sperm whale dive down to 3,000 feet to capture squid.

Recent research has identified the main components of plumes to be the toxic hydrocarbons toluene, ethybenzene, and xylenes (BTEX) in concentrations of about 70 micrograms per liter. Apparently these compounds preferred to be mixed in the water column than rising to the surface and evaporating.The compounds in the plume were found to decompose less rapidly than compounds that rose to the surface and they depleted the oxygen in the water column. The extended time these compounds spent in the water column was unexpected and has serious implications for their toxic effects on mid water level organisms in the Gulf. Handwerk reports research findings of "of oily corals and dead brittle stars" with worms and sea cucumbers completely absent from areas where they should have been found.

Dispersants were also used from above to reduce the harm caused by a spill that has reached the surface. Dispersant molecules attach to oil molecules and break large slicks up into droplets that can then be more easily dispersed by wave action and turbulence into the water column. The addition of dispersant to an oil slick will remove the oil from the surface where it was concentrated and dilute it throughout the water column by breaking the oil into droplets. This moves the oil from the surface (where many organisms inhale it or ingest it) to the bottom. As much as 1.1 million gallons of the dispersants Corexit 9500 and 9527 were sprayed in the Gulf of Mexico (Schor, 2010). Corexist 9527 was used in the Exxon Valdez spill and resulted in lingering health problems for clean up workers (probably due to 2-butoxyethanol in the disperstant). Corexit 9500 is designated a chronic and acute health hazard by the EPA. It contains propyleneglycol (a common solvent) light petroleum distillates and dioctyl sodium sulfosuccinate, a detergent and common component of laxatives. If these compounds made their way back down to the cold layers of the ocean and concentrated there then all the organisms in the Deep and Teeming and Twilight Zone of the Gulf of Mexico could have poisoned. The consequences may not yet have become apparent.

Bright Surface of Gulf of Mexico

Where sunlight can penetrate the sea water (650-3,300 feet) phytoplankton can photosynthesize and grow rapidly, producing a nutrient rich layer of watery life which provides fuel for the marine food web in the Gulf of Mexico. The phytoplankton is also a rich source of oxygen gas which enters the atmosphere and the sea water to support other forms of life. Dark oil on the surface of the water during the spill would have stopped the phytoplankton from photosynthesizing and being a small organism it would have died. However, this oil spill occurred in very deep water and not all the oil made it to the surface (Handwerk 2) and so the effects on the phytoplankton would not have been as severe as if all the oil had been spilled directly on the surface of the water, like the Exxon Valdez spill. If phytoplankton had been severely depleted by the oil on the surface, then the whole marine food web in the Gulf could have been damaged beyond repair.

Effects of Oil on Sea Birds

  • causes feathers to collapse and matt
  • changes the properties of feathers and down
  • hampers the bird's ability to fly
  • causes the breakdown of water proofing and thermal insulation provided by feathers
  • can cause the birds to lose buoyancy, causing them to sink and drown
  • severe irritation of the skin
  • ingesting the oil while trying to clean themselves
  • irritation of the eyes, skin, mouth and nasal cavaties
  • Ingest the oil via their prey
  • poisoning or intoxication

Effects of Oil on Marine Mammals

  • can cause hypothermia due to changes in their skin
  • oil can congest their lungs or damage their airways
  • can result in interstitial emphysema due to inhalation of oil droplets and vapor
  • eye and skin lesions from continuous exposure to oil
  • decrease in body mass due to a restricted diet and stress due to oil exposure

Effects of Oil on Cetaceans

  • there is very little documented evidence of whales being affected by oil spills
    • this is due to their reclusive and migratory behavior
  • since oil tends to adhere to rough surfaces, and whales are mostly smooth skin, the oil doesn't stick to them like other animals
  • baleen whales however are vulnerable to oil while feeding, since they skim the surface for their food
    • Bryde’s whales
      • Baleen whale: hair-like “teeth” in their mouths that they use to filter water and trap their food (plankton)
      • Skim-feeding in the slick results in oil in their mouths
      • the oil would quickly clog and foul the baleen
      • Fouled baleen could lead to compromised feeding, starvation and death
    • Sperm Whale (endangered)
      • Sperm whales are the largest toothed whales, and they hunt relatively large-bodied prey in deep water
        • prey may have ingested heavy oil
      • Burns to mucous membranes of eyes and mouth, and increased susceptibility to infection    
  • it is believed that pelagic whales will avoid oil spills due to the odor
  • some research also shows that whales can be effected by the oil when they surface to breathe
  • if they inhale oil droplets or vapors it could damage their mucous membranes or airways
  • dolphins are also smooth skinned, so they are less susceptible to the effects of oil absorption
    • can be harmed by inhaling the vapors or oil
    • eye sight has also been effected by oil spills
      • 400 dolphin deaths reported along the coast (Hewitt)
        • Half were baby dolphins: stillborn or newborns (Hewitt)

Effects of Oil on Sea lions, Seals, and Walruses

  • the fur of seals can attract oil and result in difficulty of swimming
  • oil also can encase their flippers and cause them to drown
  • oil will alter the animal's sense of smell which they rely on heavily to identify their young
  • because pups are usually covered by fur, they are much more vulnerable to oil spills
  • Direct skin contact with oil or dispersants can result in:
    •  Skin irritation, chemical burns, and infections.
    • Absorption of oil or dispersants
    •  Damage liver, kidney, and brain function, anemia and immune suppression.
    •  Long term decreased population due to lowered reproduction rates

Effects of Oil on Sea Turtles

  • digestion or absorption can lead to damage of the digestive tract and other organs
  • irritation of the mucous membranes leading to inflammation and infection
  • oil can contaminate the eggs during incubation potentially
    • possible increased egg mortality
    • possible developmental defects          
  • newly hatched turtles make their way form the beach and may become coated in oil
    • inhaling of volatile oil related compounds leads to internal damage or death of the newly hatched turtles
    • Kemp's Ridley Turtle (endangered)
      • One of the only foraging grounds for the Kemp’s Ridley is in area of oil spill
      • The only place in the world that the Kemp’s Ridley nests is in the western Gulf of Mexico
      • Were in the peak of their nesting season, during the oil spill
        • potential destruction of an entire generation

Effects of Oil on Fish

  • there is no evidence to suggest that oil pollution has significant effects on fish populations in the open seas

Louisiana Coastal Ecosystem

Wetlands

Dr. Susan Shaw, a marine toxicologist working with the MERI Gulf Eco-tox Project reports that in Bataria Bay, Louisiana "marshy areas are black with oil with very little growing there" and that all the sand dwelling crustaceans like mussels and clams are all dead.
In Grand Isle State Park the sand looks white but if you dig down 6 inches, you hit oil.  The tidal pools have oil on the water's surface.
She also reports a spike in complaints from coastal residents of "vomiting, breathing problems, enlarged hearts, weight loss, headaches and internal bleeding." (Hewitt)

The following observations were reported by Dr. Shaw of the MERI’s Gulf Eco-tox Project, an independent investigation into the effects of oil and chemical dispersants on marine life. (Hewitt).  

Bataria Bay

    Marshy Areas subject to tidal fluctuations

  • In tidal flats and salt marshes, oil seeps into mud
  • mud dwellers mussels and crabs: reported all dead
  • Scavenger species such as birds (eagles, sea gulls) and small predators such as raccoons feed on contaminated fish
  • biomagnification of toxins

    Sand

  • Bird and turtle nest eggs may be damaged as an oiled adult lies on the nest

  • ducks and birds that dig down into the sand to feed could ingest oil that sinks into the sand over time

    Shore Birds

  • Oil ruins water proofing of feathers
  • Interferes with ability to fly, dive for food, float on water
  • Causes hypothermia
  • Ingestion -as birds groom themselves, they can ingest and inhale the oil on their bodies. 
    • can kill animals immediately
    • causes lung, liver, and kidney damage which can lead to death
  • Only 7 birds spotted on last visit to Bataria Bay

Grand Isle State Park

    White Sand Beaches

  • oil can sink deep into the sediments
  • dug 6 inches into sand found "black, sticky oil bubbling up"

     Tidal Pools

  • oil floats on water, reports of oil sheen throughout pools
  • floating oil can contaminate plankton, which includes algae, fish eggs, and the larvae of various invertebrates
  • oil can be toxic to shellfish:  intertidal (clams, oysters, etc.) 

Economic importance of Louisiana fishing industry in the coastal wetlands/gulf coast waters

Louisiana provides 30% of U.S. seafood, 1.27 billion lbs of finfish and shellfish (2008)
Total income state of Louisiana from fishing industry $2.4 billion, 27,000 employed in fisheries

http://www.nytimes.com/2010/06/03/us/03seafood.html

Commercial fishing earned $659 million , Louisiana 75% of total U.S.
Tourist/recreational fishing in 2008- 24 million trips
Two of the largest commercial fishing operations in the Gulf of Mexico are red snapper and shrimp. Brown shrimp is the most important species in the U.S.

Revenue from oil industry will increase for Louisiana in 2017 to 37.5%, but will not count leases already established.
Louisiana has a vested interest in preserving, and increasing oil revenues in preparation for the large increase in lease royalties from the Federal Government. When it comes to deciding between preserving the wetlands and expanding more canals for oil transport and drilling more deep water...what will they decide?
Workers on off shore earn $50,000 to 100,000 a year. During moratorium on all drilling, 10,000 workers a month are idle.
The industry supports 12.7% billion in household earnings. 15% income and 14% state tax revenue in Louisiana come directly from oil revenue.

http://www.noia.org/website/download.asp?id=40016

The federal government has made more than $150 billion from the offshore oil and gas industry- more than any industry
"The Gulf states, and particularly Louisiana, have continued to be the backbone of the offshore industry, fabricating pipes, building rigs and supplying the equipment necessary to fuel an isolated industry operating in ultra-deep waters. This has increased local jobs and tax revenues."
http://sosgulfcoastrelief.com/2011/01/14/on-louisiana-coast-damage-from-oil-goes-much-deeper-than-spill/
http://wrkf.org/batonrouge&newsID=569
http://guides.lib.usf.edu/content.php?pid=121415&sid=1044272

Gulf of Mexico Oil Spill 2010

  • a website with a large amount of data and analysis




Statement: Immediate and Future Costs of Oil Spill and its Clean Up

The Gulf of Mexico the oil spill and the disperants applied caused immediate death of many organisms in the Gulf of Mexico from the deepest waters up to the surface waters penetrated by sunshine and the coastal ecosystems.

Deaths were a direct result of inhaled, or ingested oil or oil coating the skin of organisms so that they became unable to swim or breathe. Microbes that  feed on natural methane and oil seeps from the sea floor in this region would have multiplied and blossomed, with consequent adverse effects on the amount of oxygen dissolved in the water at depth. In areas where the heaviest oils have settled on the sea floor there are likely to be many more deaths of the organisms that naturally live at these depths. The existing populations of mussels, tubeworms, caridean shrimps, 20 foot long elbowed squid, giant squid, bioluminescnet fish, deep-sea jellies could all be wiped out in the future, or depleted and weakened and deformed. Large areas of the sea floor could become inhabited by oil digesting microbes alone, with a zone of oxygen depleted water around it.
 
Many deaths of large marine animals such as dolphins and sea turtles have already been observed. The endangered Kemp's Ridley sea turtle which only lives in the Gulf of Mexico could lose an entire generation as eggs were hatching throughout the duration of the spill.

Oil dispersed as small droplets and gas in plumes up through the water column would have lead to immediate deaths of many organisms in the twilight zone of water. Deaths would result from inhaled, or ingested oil or oil coating the skin of organisms so that they became unable to swim or breathe. Populations of brittle stars, anemones, urchins, chain cut sharks, galtheid crabs, giant isopids, cutlass fish, crevalle Jacks and squid could be devastated in the future from the long term health effects of the oil they inhaled or ingested during the spill and continue to inhale or ingest from any light oils remaining dispersed in the water column. The sperm whales that dive to 3,000 meter depths to feed on squid could be affected many years from now as they digest squid that have ingested oil.

Widespread devastation of the biosphere in the deep waters of the Gulf of Mexico in the long term will have devastating long term repercussions as it will leave gaping holes in the food web of the organisms that inhabit the water above and consequently the organisms that fly in the atmosphere above the waters and all the human activities from tourism to fishing that rely on a healthy ecosystem for their economic and physical health. The fact that the spill occurred at such great depth resulted in oil being dispersed throughout the water column rather than floating on the surface as in the Exxon Valdez spill in Alaska. The organisms living near the surface of the Gulf of Mexico may have appeared to escape the widespread destruction observed in Alaska, but there are many thousands of gallons of spilled oil still unaccounted for which could work its way into all living organisms in time, with damaging effects to life not seen before.

The effects of the spill on tourist trade and related business activities in the states around the Gulf of Mexico were significant during the summer and fall after the spill and many people lost their livelihoods or businesses. The tourist trade should rebound if the contamination of the beaches remains minimal and clean up efforts continue. Fishing already appears to be rebounding although many people were put out of business during the time when fishing was prohibited as a precaution to protect consumers.

The costs of the oil spill on the ecosystems of the Gulf of Mexico are not yet fully apparent, but the economic costs of not drilling in the Gulf have been huge as states have lost tax and lease revenue and many workers lost their income at a time when there a few other jobs to turn to.

References/Information Sources 

  1. Etkin D.S (1997) The Impact of Oil Spills on Marine Mammals, OSIR Report 13 March 1997 Special Report.
  2. Neff J..M and Anderson J.W. (1981) Response of Marine Animals to Petroleum and Specific Petroleum Hydrocarbons. ( Pub. Applied Science, London. ISBN-0-85334-953-3)
  3. Geraci J.R and St.Aubins D.J. (1990) Sea Mammals and Oil. Confronting the Risks, Academic Press. ISBN-0-12-280600-X
  4. Kerley, G.I.H., Bowen, L. and Erasmus, T. (1987). Fish behaviour - a possible role in the oiling of seabirds. S. Afr. J. Wildl. Res. 17, 128-130.
  5. Walraven E. (1992). Rescue and Rehabilitation of Oiled Birds (Pub. Zoological Parks Board of NSW, Taronga Zoo Sydney)
  6. Leighton, F.A. (1995). The toxicity of petroleum oils to birds: an overview. In: Wildlife and Oil Spills. Frink, L., Ball-Weir, K. and Smith, C. (eds), Tri-State Bird Rescue and Research, Inc., Newark, Delaware.
  7. Baker, A N (1983) Whales and Dolphins of New Zealand and Australia: An Identification Guide, Victoria University Press, Wellington.
  8. Harrison, Sir R and Bryden, M M (eds) 1988, Whales, Dolphins and Porpoises. Golden Press Pty Ltd, Sydney.
  9. Leatherwood, S and Reeves R 1983, The Sierra Club Handbook of Whales and Dolphins, Sierra Club Books, San Francisco.
  10. IBRRC (1985) Rehabilitating Oiled Sea Birds - A field Manual by IBRRC Pub. API Publications # 4407, 1985.
  11. 11. Jessop R. et al (1993). Regime for Treating Sick and Injured Penguins (- Pub. Phillip Island Penguin Reserve.
  12. Handwerk, Brian "Gulf Oil Spill Mystery: Is Oil on the Seafloor?" April 19, 2011 National Geographic http://news.nationalgeographic.com/news/2011/04/110420-gulf-oil-spill-anniversary-seafloor-science-nation/
  13. Handwerk 2, Brian "Gulf Oil Spill Surprises: 6 Things experts got wrong" April 19, 2011, National Geographic http://news.nationalgeographic.com/news/2011/04/110420-gulf-oil-spill-surprises-science-nation-anniversary/
  14. "Layers of Life", National Geographic, http://ngm.nationalgeographic.com/2010/10/gulf-oil-spill/gulf-life-interactive
  15. Shor, Elana "Ingredients of Controversial Dispersants Used on Gulf Oil Spill are Secrets No More" New York Times, June 9, 2010
    http://www.nytimes.com/gwire/2010/06/09/09greenwire-ingredients-of-controversial-dispersants-used-42891.html
  16. U.S. Fish and Wildlife Service "Effects of Oil on Wildlife and Habitat" http://www.fws.gov/home/dhoilspill
  17. Hewitt, Rich. " Deep water horizon still affects Gulf Coast enironment, residents" Posted April 13, 2011 http://bangordailynews.com/2011/04/13/news/hancock/deep-water-horizon-oil-still-affects-gulf-coast-environment-residents/
  18. http://www.nytimes.com/2010/06/03/us/03seafood.html
  19. http://www.noia.org/website/download.asp?id=40016
  20. http://sosgulfcoastrelief.com/2011/01/14/on-louisiana-coast-damage-from-oil-goes-much-deeper-than-spill/
  21. http://wrkf.org/batonrouge&newsID=569
  22. http://guides.lib.usf.edu/content.php?pid=121415&sid=1044272
     





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