Oil spill creates huge undersea ‘dead zone’
By Emily Dugan
Sunday May 30, 2010, 1:46 PM The world’s most damaging oil spill – now in its 41st continuously gushing day – is creating huge unseen “dead zones” in the Gulf of Mexico, according to oceanographers and toxicologists. They say that if their fears are correct, then the sea’s entire food chain could suffer years of devastation, with almost no marine life in the region escaping its effects. While the sight of tar balls and oil-covered birds on Louisiana’s shoreline has been the most visible sign of the spill’s environmental destruction, many scientists now believe it is underwater contamination that will have the deadliest impact. At least two enormous submerged clouds of noxious oil and chemical dispersants have been confirmed already by research vessels, and scientists are seeing the initial signs of several more. The largest of these is some 22 miles long, six miles wide and 3,300 feet deep – a volume which would take up half of Lake Erie. Another spans an area of 20 square miles. More than 8,300 species of plants and animals are at risk of harm. Some, such as the bluefin tuna which come to the Gulf to spawn at this time of year, could even face extinction. Scientists predict it will be many months – or even years – before the true toll of the disaster will be known. In previous spills, oil rose to the surface and was dealt with there, but due to the use of dispersants – as well as the weight of this particular crude oil and the pressure created by the depth of the leak – much of the oil has stayed submerged in clouds of tiny particles. At least 800,000 gallons of dispersants were sprayed at escaping oil in a frantic attempt to keep it offshore, but it now seems this preventative measure has created a worse disaster. The chemicals helped to keep the oil submerged and are toxic to marine life, resulting in unprecedented underwater damage to organisms in the Gulf. Once these harmful substances enter the food chain, almost nothing will escape their effects. Forests of coral, sharks, dolphins, sea turtles, game fish and thousands of shellfish could all face destruction. What happens next to these underwater clouds – or plumes as some scientists have called them – depends largely on the currents they are caught in. If they do eventually rise to the surface, they may end up on the shoreline months or years from now, causing a second wave of destruction to delicate wetlands. …
