Most of us know about oil rigs and how oil is extracted from the sea bed. This same oil is used for various purposes - from transportation, construction, to processes in chemical industries. Unfortunately, oil spilled by tankers during loading/unloading, discharging, ballasting, tank cleaning, or near offshore platforms, drilling rigs and wells, are the foremost causes responsible for ocean pollution.
Fundamentally, an oil spill is the release of liquid petroleum hydrocarbon into the environment on account of human activity. Pollution of ocean water also depends upon what kind of oil was accidentally or deliberately dumped into the ocean.
Oil can be of any type - crude oil, by-products of petroleum, or refined petroleum products like gasoline or diesel fuel, oil mixed in waste, or oily refuse. If light oil like diesel gets spilled, then this oil does not stay in the environment for a long time. It gets evaporated very easily, though it is toxic and highly inflammable. On the contrary, oil used in power ships is 'heavy', and does not get eliminated from the environment easily. Recently, it has become even a more serious environmental issue, because ocean traffic has increased considerably, which has led to the increase in number of accidents and spills.
Ten of the Worst Oil Spills Ever
Persian Gulf, Kuwait
Between 400 - 450 million gallons of oil was spilled deliberately during the Gulf War, in the year 1991. It is considered as the world's worst and the only planned oil spill ever.
Gulf of Mexico
In the year 2010, the Deepwater Horizon oil spill, also called the BP oil disaster, was considered as the world's largest offshore oil spill ever, which spilled approximately 4.9 million barrels of oil.
Bay of Campeche, Mexico
In 1979, around 140 million gallons of oil was blown out, when an oil well was drilled. Sparks ignited an accidental explosion, and it took nearly a year to stop the continuous oil leak.
Off the coast of Trinidad and Tobago, West Indies
In the year 1979, around 90 million gallons of oil leaked from the Atlantic Empress tanker, that collided with the Aegean Captain, as it was trapped in a tropical storm.
Saldanha Bay, South Africa
This oil spill occurred in the year 1983, after the oil tanker Castillo de Bellver caught fire and broke into two parts, spilling around 79 million gallons of oil.
In 1978, due to a severe winter storm, crude carrier Amoco Cadiz broke into half after the rudder got damaged, and spilled around 69 million gallons of oil into the English Channel.
Off the Coast of Angola
In 1991, between 50 - 80 million gallons of oil was discharged into the ocean, after an oil tanker exploded. This formed a large slick, which kept burning for three days, before the tanker sank completely.
In the year 1991, the tanker M/T Haven was put back into operation, even after being in poor state of repair and hit by a missile during the Iran-Iraq war. This tanker sank into the Mediterranean sea and leaked oil for nearly twelve years.
Effects of Oil Spills on...
As far as aquatic birds are concerned, the oil seeps down and disturbs its structure, feathers, and the insulating capacity. This makes them more vulnerable to temperature changes, and affects their capability to float in water. In addition to this, the flight of these birds is hindered, making them helpless when it comes to escaping from predators. Further, when they clean themselves or preen, they tend to take in the oil covering their feathers completely with it. As a result, they experience altered liver functioning, kidney damage, and irritation of the digestive tract. These problems, in tandem with restricted foraging capacity, leads to dehydration and metabolic imbalances. Ultimately, if there is no human intervention, these birds die.
Aquatic Flora & Fauna
The dangers of oil spills are mostly observed with regards to smaller marine organisms, who dwell at the bottom of the ocean. Larval fish, plankton, seaweed, mussels, oysters, dolphins, turtles, algae, and fish, are all considerably affected by it. Marine plants too are affected badly, as the layer of oil on the top creates a hindrance for sunlight to pass through, which then does not let the process of photosynthesis take place. One of the most disturbing facts is that, this decreases the amount of flora and fauna, and disrupts the entire marine food chain.
When the fur of otters gets covered in oil, it obstructs them from creating air pockets or air bubbles. These bubbles not only act as insulators and help them survive the cold weather, but also protects and helps them to float. When oil builds-up on their dense fur, they are unable to adjust or maintain the necessary air pockets or protect themselves from the change, which, in turn, leads to their death. Sometimes, these otters are taken out and placed under observation, to treat them from the oil, disease, or broken bones.
There is the possibility that the oil that has been spilled is consumed by whales either directly or indirectly. Either ways, it reaches their blowhole, which helps them breathe. Consuming oil blocks the blowhole and restricts them from breathing, which, in turn, leads to their death. In many cases, it also happens that whales gobble up small fish who have swam through the oil before becoming their food. The oil reaches the whale's system, poisons it, and eventually leads to its death.
These were just the common ways of how oil spills affect the oceans. There are, in fact, innumerable facets to this issue. It needs a serious thought and action on our part, so that we can try and save marine life and fight environmental pollution, which is destroying our planet bit by bit.