exploring oceans 3b CASE STUDY Deepwater Horizon

Background info

• 2010

• Oil rig located 40 miles off coast of Louisiana exploded

• BP was the oil company operating the oil rig

• 1500m water depth

• 11 workers killed, 17 injured

• 210 million gallons of oil released

• Largest oil spill in history

• Happened due to technical and engineering failures

• Oil was light crude, dissolves in water more readily than heavy crude. Some floated to ocean surface where it evaporated, surface oil driven by winds and currents to shore. Some oil trapped in deep ocean layers below 1000m, some sank to the floor.

• 2,000,000 gallons of oil leak per day naturally in the Gulf, the Gulf also recieves lots of pollutants from land via rivers. Runoff from farmland- pesticides, insecticides with excess nutrients

• 25% evaporated

• Impact on humans- cleanup workers, volunteers reported elevated rates of respiratory issues, skin and heart conditions linked to crude oil and chemical dispersant exposure

Impacts on the physical environment and marine ecosystems

• Entire marine ecosystem along gulf coast was affected but impacts were short term

• Media published images of oil soaked birds, fish, turtles and mammals such as dolphins. Mortality among heavily affected creatures like these was high

• Some species- pelicans, seaside sparrows show no long lasting effects on their numbers but oil does still wash up in places and deposits remain on the seabed covering now dead coral reefs

• Over 8600 dead animals

• Location most affected- coastal salt marshes. Oil accumulated in mud meaning in anaerobic conditions oil wasn’t broken down by bacteria

• Over 1100 to 1300miles of coastline across Louisiana, Mississippi, Alabama, Florida, Texas were polluted- damaging salt marshes, mangrove fringes

• Long term- deep sea surveys show lasting ecological disruption; declines in deep sea fish (down over 60%)

 

 

Impacts on human activities such as fishing and tourism

• Fishing industry along gulf coast is one of the most productive in the world (shrimp, oysters, fish), important for regional economy and employment. In the short term, fishing stopped and there was a loss of income for those involved in the industry

• Tourism industry along gulf coast badly hit, media images of contaminated beaches meant that few people wanted to visit in the short term after the spill.

• Loss of income and unemployment followed this, general downward spiral of the economy in coastal communities

• 5 years after the spill the gulfs fish and oyster industries can sell their catch, virtually all beaches open

• BP faced financial penalties including over $18.7billion in settlement costs and clean water act fines

Management of the oil spill and its impacts

• 1.84mil gallons of dispersants used (chemicals to break the oil into smaller particles to prevent oil slicks)- helped clear visible oil from surface but introduced toxic chemical compounds into the water, secondary ecological risks for marine life which could last for a longer time.

•  oil washed up on beaches, contaminated sand scooped up mechanically or shovelled by hand into piles for collection

• Skimmer boats scooped oil

• Artificial barrier islands constructed just offshore in some places to act as physical barriers to stop oil reaching shore. However, these were soon washed away by waves and currents in the Gulf

• National response team led by US coast guard- engineers attempted siphoning, performed controlled surface burns. The response involved around 48,000 personnel, 6500 vessels

• Prompted a temporary moratorium on deepwater drilling along the US outer continental shelf and stricter safety regulations for offshore energy firms.

 

Why oil?

• Abundance of it

• Cheap, in the US a gallon of gasoline can be cheaper than a bottle of water, too cheap for most people to bother conserving it

• US majority of consumers, use a quarter of the worlds oil, about 3 gallons per person per day

• But earth holds a finite supply of oil, will run out at some point in the future