Oil spill and its effects on life

What is an oil spill?

An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is usually applied to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil spills may be due to releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.

Oil spills penetrate into the structure of the plumage of birds and the fur of mammals, reducing its insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Spills may take weeks, months or even years to clean up.

Effect on life Terrestrial life

• Animals that rely on scent to find their babies or mothers cannot due to the strong scent of the oil. This causes a baby to be rejected and abandoned, leaving the babies to starve and eventually die.
• Oil can impair a bird's ability to fly, preventing it from foraging or escaping from predators.
• As they preen, birds may ingest the oil coating their feathers, irritating the digestive tract, altering liver function, and causing kidney damage.
• Together with their diminished foraging capacity, this can rapidly result in dehydration and metabolic imbalance.
• Some birds exposed to petroleum also experience changes in their hormonal balance, including changes in their luteinising protein.
• The majority of birds affected by oil spills die from complications without human intervention.
• Some studies have suggested that less than one percent of oil-soaked birds survive, even after cleaning, although the survival rate can also exceed ninety percent, as in the case of the Treasure oil spill.

Marine Life

• Heavily furred marine mammals exposed to oil spills are affected in similar ways.
• Oil coats the fur of sea otters and seals, reducing its insulating effect, and leading to fluctuations in body temperature and hypothermia.
• Oil can also blind an animal, leaving it defenseless.
• The ingestion of oil causes dehydration and impairs the digestive process.
• Animals can be poisoned, and may die from oil entering the lungs or liver.
  

Oil consuming bacteria:

• There are three kinds of oil-consuming bacteria.
• Sulfate-reducing bacteria (SRB) and acid-producing bacteria are anaerobic, while general aerobic bacteria (GAB) are aerobic.
• These bacteria occur naturally and will act to remove oil from an ecosystem, and their biomass will tend to replace other populations in the food chain.

World’s ten largest oil spills:

Gulf War, 1991

• Oil spill at Kuwait, which released 240 to 336 million gallons.
• As Iraqi forces retreated from Kuwait during the first Gulf War, they opened the valves of oil wells and pipelines in a bid to slow the onslaught of American troops. The result was the largest oil spill history has seen. Some 240 million gallons of crude oil flowed into the Persian Gulf. The resulting oil slick spanned an area just larger than the size of the island of Hawaii.
• However, the largest oil spill the world has seen exacted little permanent damage on coral ecosystems and local fisheries, according to a report by the Intergovernmental Oceanographic Commission at Unesco.
  

Deepwater Horizon 2010

• Oil spill at Mexican Gulf, which released 210 million gallons.
• The BP oil spill flowed for three months, becoming the largest accidental marine oil spill in the history of the petroleum industry. The spill stemmed from a sea-floor oil gusher that resulted from the April 20, 2010, explosion of Deepwater Horizon, which drilled on the BP-operated Macondo Prospect. The explosion killed 11 men working on the platform and injured 17 others.
• On July 15, 2010, the leak was stopped by capping the gushing wellhead, after it had released about 4.9 million barrels of crude oil. An estimated 53,000 barrels per day escaped from the well just before it was capped.
• The spill caused extensive damage to marine and wildlife habitats and to the Gulf's fishing and tourism industries. Skimmer ships, floating containment booms, anchored barriers, sand-filled barricades along shorelines, and dispersants were used in an attempt to protect hundreds of miles of beaches, wetlands, and estuaries from the spreading oil.
• Scientists also reported immense underwater plumes of dissolved oil not visible at the surface as well as an 80-square-mile "kill zone" surrounding the blown well.

Ixtoc 1 Oil Well, 1979

• Oil spill at Bay of Campeche, Mexico, releasing 140 million gallons.
• In June 1979, an oil well in the Bay of Campeche collapsed after a pressure buildup sparked an accidental explosion. Over the next 10 months about 140 million gallons of crude spouted into the Gulf of Mexico from the damaged oil well. In order to slow down the flow of oil from the damaged well, mud and later steel, iron and lead balls were dropped down its shaft. The resulting slick measured 1100 square miles.

Atlantic Empress, 1979

• Oil spill at Trinidad and Tobago, West Indies. Releasing 88.3 million gallons.
• One stormy evening in July 1979, two full supertankers collided off the coast of Tobago in the Caribbean Sea, precipitating the largest ship-sourced oil spill in history. Crippled by the accident, both vessels began to leak their crude and caught fire. One of the tankers exploded 300 nautical miles offshore, killing 26 crew.
• Luckily, only minor shore pollution was reported on nearby islands.

Fergana Valley, 1992

• Oil spill in Uzbekistan with release of 87.7 million gallons.
• Nearly 88 million gallons of oil spilled from an oil well in Fergana Valley, one of Uzbekistans's most active energy- and oil-refining areas. While the spill didn't get much press at the time, it is the largest inland spill ever reported. The ground absorbed this spill, leaving nothing for cleaning crews to tackle.

Nowruz Oil Field, 1983

• Oil spill in Persian Gulf, releasing 80 million gallons.
• During the Iran-Iraq War, an oil tanker crashed into the Nowruz Field Platform in the Persian Gulf and knocked it askew, damaging the well underneath. The oil well then leaked about 1500 barrels a day, but because it was in the center of a war zone, seven months went by before it was fixed.

ABT Summer, 1991

• Oil spill in Off the coast of Angola, releasing 80 million gallons.
• En route to Rotterdam, the fully loaded tanker ABT Summer experienced an explosion onboard and caught fire while it was 900 miles off the coast of Angola, leaking its payload into the ocean. Surrounded by a growing oil slick that spanned 80 square miles, the tanker burned for three days before sinking. The oil is thought to have been broken up by high seas at little environmental cost, thanks to the incident's offshore location.

Castillo de Bellver, 1983

• Oil spill at Off Saldanha Bay, South Africa, releasing 78.5 million gallons.
• The tanker caught fire about 70 miles northwest of Capetown, South Africa, on August 6, 1983. The blazing vessel was abandoned and drifted offshore until it eventually broke in half. The stern capsized and sank into the deep ocean. The vessel was carrying nearly 79 million gallons of crude at the time of the accident. About 1500 gannets that happened to be gathered on a nearby island, gearing up for their breeding season, were oiled, but the impact on local fish stocks was minimal.

Amoco Cadiz, 1978

• Oil spill in Off Brittany, France, releasing 68.7 million gallons.
• The tanker ran aground off the coast of Brittany after its steering failed in a severe storm. Its entire cargo of 246,000 tons of light crude oil was dumped into the roiling waters of the English Channel, with the grim consequence of killing off more marine life than any other oil spill to date at the time. Cleanup efforts were foiled by strong winds and heavy seas and less than 3300 tons of dispersants were used.
  

Odyssey Oil Spill, 1988

• 43 million gallons of oil released in 700 nautical miles off the coast of Nova Scotia, Canada.
• In November 1988 the Liberian tanker Odyssey, avirtually full to the brim with North Sea crude oil, broke in two and sunk in the North Atlantic 700 miles off the coast of Nova Scotia.