Biology

Abstract
Oil supertanker wrecks and breaches have devastated several pristine ocean habitats during the past 40 years. The oil spills from these disasters, often spreading hundreds or thousands of square miles across the water surface, have killed millions of birds and animals and have thrown vast ecosystems into great and enduring turmoil. The Exxon-Valdez in 1989 and the Amoco Cadiz in 1978 are prime examples of such largely preventable and unnecessary catastrophes that have left enormous tragedies in their wake. Although cleanup operations are usually initiated promptly and carried out diligently, their effectiveness could only be limited. New regulatory measures that have been enacted since the Exxon-Valdez are seeking to curb the numbers of these disasters and restrain the damage they cause even if they occur.

Introduction
We live in a world that is literally run on oil. Our economy is still very much a fossil fuel economy. Decades of unrestrained use of fossil fuels has been heavily polluting our cities and would be instrumental in unleashing global cataclysms in the future, as a result of the now virtually unstoppable global warming process. The other side of this scenario of devastating pollution is the contamination of oceans caused during the extraction of oil from the ocean beds and their subsequent transfer in giant supertankers. These supertankers routinely course the oceans bearing precariously millions of tons of crude oil in their mammoth hulls. The oceans of the world generally tend to treacherous for navigation, given to very volatile weather conditions added to this, oil rigs and oil ports are often located in remote areas of the world and the waters surrounding them tend to be especially dangerous to negotiate. Accidents tend to happen, though they need not if the responsible people exercised more care and caution in planning and carrying out these massive oil transfer operations. Accidental breaches of the tankers hulls often turn into major disasters, devastating vast ocean ecosystems.

When oil-laden supertankers meet with accidents in transit, colossal amounts of oil pour into the water and wreak havoc upon the marine environment. Although people do not usually die in such disasters, they are tragedies of enormous proportions. In the 20th century, millions of seabirds have died grueling deaths owing to oil tanker accidents, and this is just a part of a vastly bigger picture  a grim and dismal picture of widespread devastation. If we take the Exxon-Valdez disaster of 1989, which is perhaps the most well-known of oil-tankers disasters (although there have been many more oil disasters which surpass Exxon-Valdez in terms of sheer volume of the oil discharge), the numbers of the animals that perished at Prince William Sound, Alaska, as a result of this mishap are staggering. An estimated 100,000 to 250,000 seabirds, 2,000 sea otters, 300 harbor seals, 250 bald eagles and so on died in the immediate aftermath of the incident. Again, the numbers of immediately dead animals and birds is just one aspect of a much extensive ecological damage lasting years and decades, one that still continues.

The Torrey Canyon off the coast of Cornwall, UK, in 1967, the Exxon Valdez, the Baer in the Shetland Islands off the northern coast of Scotland in 1992, the Amoco Haven in the Mediterranean Sea off the Italian coast near Genoa in 1991 and the earlier Amoco Cadiz off the French Coast near Brittany in 1978  these are some of the more publicized disasters. However there have occurred many more disasters such as these, though barely making it to the headlines for more than a day or two. If the Exxon Valdez spilled 35,000 tons of crude oil into the ocean, the Gulf War oil spill, reportedly the worst oil spill in the history and caused by deliberate actions of Iraqis, discharged nearly 1,500,000 of crude. The scale of these disasters is even difficult to conceive.

Lets take a closer look at the Exxon-Valdez, in order to better grasp the enormity of the disaster essentially caused by some silly negligence in navigation and for no other reason. On March 1989, the Exxon Valdez left the oil port at Valdez, Alaska, on its way to Long Beach, California. The ship struck the Bligh Reef within three hours of its departure. The vessel was carrying 54 million U.S. gallons of oil, out of which nearly 11 million gallons were spilled into the Prince William Sound, although this figure could be an underestimate. The cause of the accident has been ruled as human error.  The spill eventually (over a period of nearly two months) impacted an area of 1,300 square miles.

Clean up operations were immediately underway from the next morning itself, although not on a scale commensurate with the disaster in any way. To complicate the matters, a storm just three days after the disaster dispersed huge quantities of oil onto the rocky shores and beaches of neighboring islands. Exxon was widely criticized for its inadequate and tardy response to the situation, but extensive cleanup attempts were launched in the years following the incident, mainly during the first four years. Exxon spent 2 billion in the cleanup efforts. Thousands of volunteers and workers, over a thousand boats, over a hundred planes, a great number of Navy and Air Force resources figured into the cleanup operations (Cleveland). Regardless, a study made by NOAA in 2007 reported that more than 26,000 gallons of oil still remained seeped deep into the shoreline.

The impact of this incident on the environment was both short-term and long-term in nature. Beyond the thousands of animals and birds and billions of eggs which faced death and destruction very soon after the disaster, the suffering of the surviving marine creatures and their offspring (inhabiting the fringes of the spill or those that are otherwise indirectly affected through the food chain) continued for decades. There have been drastic reductions in marine animal populations, and stunted growth was seen in some species. Some species, such as killer whales, cormorants, and harbor seals, are considered to be not recovering at all, while other species such as sea otters and mussels are considered to be on the way to recovery. Only a very few species, such as bald eagles, are deemed to have recovered, while the status of some other species, mainly fish, is unknown.  It may take at least a decade or two yet for this expansive ocean habitat to recover to normalcy. Besides the wild life, the economies of Valdez, Cordova, Anchorage and other Alaskan towns and cities took a major blow from this accident. The industries that were directly hit were however compensated by Exxon. The litigation process over the punitive charges that had to be imposed on Exxon went on for decades, and in the end, by 2008, Exxon managed to reduce the original 5 billion plus interest charges to a mere 500 million.

Many bigger oil tanker disasters have happened both before and after the Exxon Valdez. But the Exxon Valdez is considered as one of the most catastrophic of human-caused environmental disasters of the 20th century, mainly because it occurred in one of the most pristine locations on the earth, a haven for wildlife and in fact a tourist attraction. Numerous lessons have been learnt from the disaster itself and the subsequent cleanup operations, and as a result some regulatory and operational changes have been implemented, such as the Oil Pollution Act of 1990. The Exxon Valdez incident itself and the attention it received have led to a heightening of safety concerns regarding oil supertankers and contributed to bringing down the likelihood of major oil tanker disasters in the oceans.

A very interesting fact about the Exxon Valdez is that if only the vessel had a double hull in the place of a single hull, the amount of oil that was discharged could have been cut down by 60. The cost of a double hull alone would amount to 50 of the entire single-hulled oil tanker, but notwithstanding its cost it could play a crucial role in mitigating the effects of an accident. To have a double hull for oil tankers would become mandatory from 2015 onward, and we can expect the number of oil supertanker disasters to further decline thereafter.

The Amoco Cadiz disaster on Frances Brittany coast happened over a decade before the Exxon-Valdez. It was one of the biggest ship-wrecks in history. The oil spilled from it, nearly 225,000 tons of crude oil (equivalent to 68 million gallons), affected 240 miles of French coast. The casualty figures 20,000 birds, 9,000 tons of oysters, millions of dead mollusks and sea urchins. This disaster for the first time presented TV audiences the sad plight of oil-coated birds and other marine creatures.

From the 1967 Torrey Canyon to 2007 Herbei Spirit which discharged 2.8 million gallons of crude oil very close to South Koreas west coast, oil tanker disasters have been ravaging the worlds oceans. There have been over 20 major disasters the world over in the span of 40 years. The ecological devastation they have been causing is enormous. The damage they inflict should be measured not only terms of figures and statistics, but also in terms of actual suffering they cause to innocent birds, animals and fishes. Most of the birds and animals exposed to oil spills do not die instantly but die prolonged deaths, experiencing great torment. As the oil penetrates the plumage of the birds, it leads to several consequences. The birds insulating ability is reduced making it vulnerable to hypothermia, the bird becomes less buoyant in the water, and significantly less capable of air flight. These two factors make it very difficult for the bird to find food and defend itself against predators.  Also, in the attempt to preen and clean themselves, the birds ingest oil toxic and carcinogenic compounds in the oil damage the birds internal organs and kill them slowly, subjecting them to various disabilities and illnesses. There is very little chance for the survival of the birds caught up in an oil spill. Marine mammals such as sea otters and seals suffer a similar fate as that of birds. Their lives become insupportable in the black world oozing thick oil from everywhere. Most of these birds and animals would die without the aid of human intervention, but even when these creatures are de-oiled with great effort and released into safer environments, usually very of them survive.

Fishes are also the victims. Heavier-than-water oil products as well as the heavier fraction of crude oils sink to the bottom of the ocean where they coat the fish populations. Vast stretches of phytoplankton and zooplankton would also be killed or rendered toxic. Whole ecological systems, with their complex web of food chains, would be severely taxed and disturbed.

Since oil floats on the surface, large discharges may cause long-term damage to the surface environment by destroying elements of the ocean food chain, especially plankton, fish, and birds. Living organisms coated with oil seldom survive. Oil is a continuing threat to a range of highly sensitive ocean environments, including coral reefs, coastal wetlands, and fish spawning areas.

Over the years, as the technology improved, the effectiveness of cleanup operations too has increased. Usually, an oil spill is treated in multiple ways. Dispersant particles gather clusters of oil globules around themselves and carry them away. These can be later scavenged more easily. Sorbents are used to absorb the oil. In the method called bioremediation, oil-eating bacteria and other microorganisms or biological agents are used to break down the oil. Besides these, a wide variety of manual and mechanical processes employing tools such as shovels, booms, and dredging equipment are put in place. Sometimes more sophisticated equipments such as high-speed oil containment systems are used. But no matter how intensive and extensive the cleanup efforts are and whatever technologies may be used, it is very difficult to reach a satisfactory degree of cleaning up in the context of such huge disasters the cleanup can only be considered as a damage control operation.

Oil tanker disasters in the ocean have caused and in the future are still likely to cause massive damage to ocean environments. However, they constitute only a part, and in fact the lesser part, of total oil contamination of the oceans. The majority of the oil pollution of the ocean waters happens deliberately, as when oil tankers are flushed with sea water. Done on a collective scale, such routine flushing of oil tankers discharges millions of gallons of oil into the ocean every year, but all of it goes unnoticed.  Crude oil and refined products spill also happens regularly from routine operations of offshore oil rigs, as well as leakage from undersea pipes.  These oil spills have enormous impact on the neighboring marine life. The Ocean continues to suffer.

Conclusion
The world has first encountered the heart-breaking images of teeming birds and animals submerged in a sea of oil over 30 years ago. That was also the time when the environmental movement had just begun to take off. Since then the sad sight of ocean devastation caused by oil tanker accidents has become almost commonplace. These images and the enormous figures of destruction associated with them naturally evoke horrified reactions from the common people. These disasters should not happen. Man has no right to inflict pain and death on such a huge scale on beautiful and innocent birds and animals. These disasters need not have happened too if not for the lack of resolve on the part of the people and authorities concerned. It can only be hoped that the past four decades of oil tanker disasters will remain an episode of dark legacy of the twentieth centurys hunger for oil, and in the decades to come we will go beyond our dependence on oil and the massive disasters associated with it.