April 30, 2010

further reaction to oil spill of the Gulf of Mexico

Since the explosion on the oil rig occurred on 20 April, the rate at which oil is pouring into the sea has been found to be much higher than originally thought, while there are reports that the oil has begun to wash up on the Gulf Coast.

Dr Simon Boxall, National Oceanography Centre, University of Southampton, said:

“The spill that is ongoing off the coast of Louisiana is unremarkable in some ways, unique in others. Oil seeps from the sea bed around the world naturally and has done long before mankind was on the planet. In fact more enters the environment this way than through all of the combined accidental spills from shipping and well head incidents. What is unique is the size of the seep in this instance. Compared to some accidents the volume of oil pouring into the sea thus far is not remarkable – what will be remarkable is the amount of oil likely to spill before the well is capped.

“Oil extraction from the deep sea is new and the technology used at the cutting edge. Well head incidents on land or in the shallow (50-100m) North Sea are relatively easy to cap and the methods are tried and tested. At 1500m the head is as easy to get to as if it were on the moon. The water pressures are huge and the logistics very complex. This incident was unfortunately going to happen somewhere in the Gulf of Mexico one day and it has now done so. BP are in the unfortunate position of having to pioneer ways of dealing with it which are new and untested and this will take weeks if not months. Many have asked why isn’t there some form of “safety valve” or “stop cock” to turn the oil off. There was, and it is this that has gone. It is like the mains stop cock in the street for your house. If a water leak occurs in the house or in the driveway then you just turn off the mains stop cock while you deal with the problem. But what do you do when the mains stop cock breaks?

“Estimates of the spill vary enormously as it is hard to determine exactly how much is being lost from the head at such depths. The other issue is that as the oil rises from these depths through the mile of water it is likely to become modified making it less easy to pick up at the surface. The option of burning is generally not to be recommended as this transfers the problem from the marine environment to the atmosphere and will still leave a significant amount of oil in the ocean, often in a modified and more harmful form. While the winds blow it offshore doing nothing is the safest option. Experience from a number of incidents including the Exxon Valdez showed that minimal intervention once the oil flow had been stemmed was the best environmental option. Crude oil is a natural product and it does biodegrade and disperse naturally in the ocean fairly rapidly.

“Where intervention is needed is where the oil is pushed ashore into commercially or environmentally sensitive areas such as the Gulf coast’s wetlands. Home not only to a thriving fishing industry but also a substantial nature reserve the potential for damage is enormous. Booming the area off with floating dams to protect these areas is the best option but the size of the spill will exhaust the world’s supply of oil booms very quickly. Recovering the oil as it surfaces is also an option, but the mile journey from the sea bed means it doesn’t surface as a neat pool to tackle. We just need to hope that the oil engineers can come up with a solution to cap the well soon and that the winds blow offshore in the meantime.”

Prof Chris Frid, Professor of Marine Biology, Head of the School of Environmental Sciences, University of Liverpool, said:

“Oil slicks on the sea surface offshore are not as ecologically damaging as many people assume – the biggest threat they pose is to seabirds. Once oil comes ashore it has the potential to impact on much more ecological and economic activity.

“One of the lessons from the Exxon Valdez spill should have been the additional damage that occurred because the US authorities delayed spraying with dispersants. Once oil has been on the sea for a few days it is much harder to break up. In this case with the source of the oil far offshore and with fresh oil bubbling to the surface spraying would be the most effective measure.

“The dispersed oil is less of a threat to marine life, gets dispersed over large areas and is more readily broken down by bacteria. It would appear that delays in getting spraying started and concerns about the supply of dispersant are resulting in oil reaching the shore. As fresh oil is continually emerging at the sea surface, the US authorities should focus on protecting the vulnerable habitats at the coast and maximise spraying offshore. Fisheries resources are unlikely to be affected but the oil will prevent fishing and marketing of catch, due to contamination and poor public perception, and fishermen will need to be compensated.”