By Jerram Watts
Environmentalists are fearing for the health of marine life as engineers battle to stop oil haemorrhaging from the Deep Horizon oil rig in the Gulf of Mexico.
The oil rig explosion on April 20 killed 11 crewman and sank two days later, instigating a spill with potentially devastating consequences.
It is estimated 400-600 species are potentially at risk from the blowout, as the oil draws nearer to the Louisiana coast.
WWF Australia Conservation Director Dr Gilly Llewellyn says the southern coast of the US is one of the worst places the spill could have struck.
“I’ve seen descriptions of the Louisiana coast being the Chicago O’Hare Airport for the migratory bird world at that time of year – and the beaches and sand dune being described as the main runway,” she says.
“If they are landing on habitats that are coated in oil, or picking out what they think is food which is covered in oil, then you start that contamination chain.
“If you look at the area surrounding and the curve to north of the spill, you’ve got a whole system of barrier islands – which are natures first line of defence against storm waves."
It is these barrier islands that are often the preferred site of shore bird species, like terns, very delicate creatures who have their nests and eggs on that sandy environment, Dr Llewellyn says.
Storm waves could force the oil booms ashore, losing the line of defence, meaning the nesting birds will be at risk of contamination, she says.
Dr Llewellyn has studied the effects of oil spills on the environment – she studied with senior conservation scientists in the US for more than 10 years and in late 2009 she travelled to Timor to assess the damage from the blowout of the Montara Exploration well head.
Though less than one-tenth the scale of the Deep Horizon disaster - Montara was leaking 400 barrels a day, compared to Deep Horizon’s estimated 5000 - the blowout still took 73 days to plug.
Dr Llewellyn says a lot was learnt from spill.
“The risks might be small, but when they happen the consequences can be enormous,” she says.
“It took them more than 70 days to drill an interception well, it took them at least four goes to hit the jackpot – it’s a tricky engineering solution [for Deep Horizon], it’s like threading a needle kilometres underground, using remote drilling equipment.”
Dr Llewellyn says more than this they saw, and learnt from, marine animal behaviour during the spill.
“We saw pods of dolphins surfacing alongside our boat – you could smell the oil, it was like being in a petrol station. The smell was in the air, it was a heavy film on the surface of the water, yet we were seeing dolphins surfacing through that," she says.
“Every time they would have come in contact there are direct effects on the skin, the eyes, potentially getting into mucous membranes, through the blowhole into the mouth of the dolphin.”
However Dr Llewellyn says the indirect effects of the oil can often be worse.
“The dolphins are out there hunting, looking for fish – those fish potentially are ingesting oil and becoming laden with toxic chemicals."
The indirect effects could result in a greater susceptibility to disease and perhaps decreased reproductive success, Dr Llewellyn says.
“Heavy oiling could lead to death, but over the long term, exposure could have chronic longer-term effects and that’s why long-term monitoring is so important in these situations.
“Over a matter of years do they continue to grow at what we would expect to be the natural population rate, or do we start seeing changes, as in the decline in size or no evidence of new calves?”
The oil rig explosion is a reminder the world needs to move towards safer, cleaner energy, says WWF international director general James Leape.
“The ecological and economic devastation now unfolding in the Gulf of Mexico is a reminder that offshore oil exploration and production is in fact deeply hazardous and we should think twice before opening up even more delicate and treacherous waters to development,” he says.
The Deep Horizon spill is expected to surpass the 1989 Exxon Valdez disaster - the worst US marine oil spill in history, and consequences of which are still evident.
“You wouldn’t have to dig down too far in the area where the spill hit and you can still see oil oozing out of the sediments there,” Dr Llewellyn says.
“That was a heavy bunker oil, literally a black tide. My understanding is that the oil in the Gulf of Mexico is lighter than that, it’s probably more of a medium to light crude.
“All types of oil have toxic effects, that’s why it will be years, it will be longer depending on whether the slick reaches some of these environments, particularly ones where you’ve got fine grain sediments.”
It is those fine grain sediment marshlands that could bear the long term consequences.
“In those environments you’ve got finer, muddier sediments… if you get oil in quantities back into those quiet water environments, it’s going to get into the mud – then, rather than wetlands being described as ‘the kidneys of our coastal systems’ where they are filtering things out, if you’ve got toxins stored in there they could be leaching out into the system – and that’s where there is real concern in the shrimp and ouster fisheries.
“If it gets into the system it could be years when we are still seeing the footprint of the spill.”
Engineers will this weekend attempt to stem the flow with a large 100-tonne box placed over the leakage – one of the taps was sealed Tuesday night.
In all, about 7,900 people are working to protect the shoreline and wildlife, and some 170 boats are also helping with the cleanup.
Make no mistake, Dr Llewellyn says, there is no shortage of oil under Deep Horizon.
“They were drilling in deep water. You don’t make the investment needed to do that deep activity if you haven’t got a big prospect, so there’s a lot of oil down there," she says.
"This thing is not going to stop by itself anytime soon.”
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