Costs and Effects of Oil Pollution
Having millions and millions of gallons of oil in the world’s oceans has a major impact on the environment.
The most vivid images of oil pollution seen by us are those large spills that have an apparent and instant effect. Images on the television and in news papers of oil soaked birds and beaches stick in our minds. After a spill, an oil slick spreads across the water’s surface, then washes up on the beach coating animals and plants that come into contact with it both on and off shore. The effects are spread across a huge array of wildlife. All the costs discussed here are particularly relevant to a spill but the gradual oil pollution caused by ongoing contamination through drainage and industry has the same effects.
Regardless of how the water gets into the sea, its substance is lighter than the density of water. This means that it floats on the surface of the sea (occasionally very dense oil can sink). The oil spreads along the surface of the ocean forming an oil slick, and the flow of the tide spreads it further from the source until it becomes thinner and thinner eventually turning into a sheen. The sheen has a rainbow like appearance similar to that on road surfaces after heavy rain.
Some of the oil (up to 10-30%) sticks on to or gets absorbed by physical material floating or hanging in the water. This drops to the ocean floor and usually happens in more shallow waters. Oil can also form into lumps which can stay in the ocean or wash up on beaches. These can exist from a month to a year in the enclosed seas and up to several years in the open ocean [Benzhitski, 1980].
Oil lumps and slicks affect the ecology system both within the ocean and on affected coastlines. Animals and birds become coated in oil which destroys their insulation and they also swallow it when they try to clean themselves.
Sea birds are particularly vulnerable to oil pollution. Usually water will run off a bird’s feathers because of the overlapping structure. This top layer of feathers protects the insulating layer of down beneath. Both layers work together to keep the bird warm and waterproof. When the oil coats the bird it clogs the delicate barbs that work to interlock the layers. Naturally a bird will clean to free itself of the oil, swallowing residue and inhaling toxic fumes. Oil is also swallowed via feeding. However oil is ingested, it is poisonous. The oil quickly damages the waterproofing and insulation qualities of feathers. In order to keep its energy levels up, a bird needs to get more food, using up even more energy with the added weight of wet feathers. Unless it is rescued the bird is caught in a downward cycle, and most birds die through starvation, drowning or hypothermia.
Fish and turtles that need to surface and breathe can also be affected by oil. As they surface, they become coated, and as with birds, they ingest the oil through feeding.
Generally animals and fish move towards shallow waters to breed or, in the case of turtles, come ashore. Turtles have to fight their way along the polluted beaches and eggs covered in oil are not likely to survive. Oil can penetrate the shell coating and effect the embryo directly. Juvenile fish born in shallow water have a low survival rate as the concentration of oil is higher.
Coral is another living organism that is directly affected by oil. Reefs are made up of living coral which grows on the dead calcified coral colonies. If the living coral is killed through oil pollution, the dead coral, home to an intricate ecosystem, is unprotected and vulnerable to erosion by the sea. Any oil coating on coral is bound to affect the thousands of fish and plants that make the coral their home.
All animals affected by oil pollution are at risk from liver damage, blindness and hereditary defects through the toxins.
We know the food chain in any eco-system is delicate, and changes to it can have far reaching effects. Plankton a common food source for animals such as whales and is sensitive to oil pollution. It is poisoned or killed off. Any animals using plankton as their source of food can become ill through eating it, or find their food rapidly decreasing. This is the same for fish who ingest oil and in turn are eaten by predators. The oil will remain in the food chain affecting a large span of wildlife.
Plants, such as mangroves, which grow along the coastline, have their roots covered in oil after a spill. The root system is how they take in nutrients and oil will be either sucked in or block the plants breathing system. This can be lethal.
The rocks and coast become covered with viscous, sticky oil when it washes ashore making it inhabitable for animals and plant life.
The damage caused by oil pollution depends on the amount of oil involved and the type of oil spilled. Effects can be long term, oil the collects in areas with little sunlight or wind for dispersal can remain for many decades, and in polar areas even centuries. Oil can both float and sink so damage affects the surface and the bottom of the ocean ecosystem. Even if oil exposure isn't immediately lethal, it can cause long-term harm.
To reduce the impact of oil on local industry, the clean up needs to be rapid. Techniques which provide a quick result are not those that are the best for ongoing survival of the eco system. One example is the Torrey Canyon grounding in Cornwall England in 1967, when thousands of tonnes of chemicals were sprayed over the seas and beaches to dissolve the oil. Unfortunately, the chemicals used were more harmful than the oil itself, causing further devastation of the environment. Since 1967, there have been improvements in cleaning since the Sea Empress grounded and caused a spill. The chemicals were not washed away properly, killing wildlife that had survived the initial spill.
Other quick clean up methods are the uses of machinery for example bulldozers. These huge machines also damage the local environment raking up earth that has not been damaged as well as the polluted land. Many ecologists also point to the lack of preparation for oil spills by governments. For example, Galicia in Spain has suffered six large spills in recent years, but despite there being a strong marine science influence in that area (4 nearby research institutes); there is little communication between the local government and scientists who understand the best protection methods.
Coastal based industries are severely affected by oil pollution. Tourist industries rely on clean water for sporting activities and beautiful coastlines for sunbathing and sightseeing. How many people would want to visit a black sticky beach, littered with carcasses of dead sea life? Some industries rely on clean seawater for their operations. Fishermen need healthy fish to catch and sell and oil pollution is known to effect long term survival rates of fish populations.
The damage caused by pollution and highlighted through the media will reduce the public’s confidence on fish caught, and the tourist appeal of the areas can take many years to rebuild. The livelihood of communities that depend on coastal industry for survival can be seriously damaged.
One oil spill disaster which many people will remember is the Exxon Valdez in 1989. Study has been completed on the long term effects that this tragedy had on the environment. Immediate deaths from the spill are estimated as 250,000 seabirds, 2,800 sea otters, 300 harbour seals, 250 bald eagles, up to 22 killer whales, and billions of salmon and herring eggs. Oil affected approximately 1,300 miles of coastline and the spill covered an area of 460 miles.