http://www.timesonline.co.uk/tol/news/environment/article7145370.ece
Be Well.
David
What will be left after the oil spill?
No dolphins... no whales... no bluefin tuna... no swordfish... no turtles... no coral beds... no plankton... The first man to dive below America’s worst environmental disaster looks at the evidence
Thirty feet down in the Gulf of Mexico, the water suddenly goes dark. Above me, a ragged black silhouette of oil is eclipsing the sunlit circle that is the surface. I feel a familiar twinge in the back of my brain, the first warning that soon I need to get back up to breathe. With concentrated calmness, I pause and hang in the water, staring. Oil is above, around and beneath me; out of sight somewhere way below lurk yet more dark clouds of oil. This is now America’s worst environmental disaster, according to the White House. The beaches are clogged not only with oil, but with clean-up workers, TV crews and politicians. But it is here, beneath the slick, that its destructive power will be most felt.
The silted tongues of the Mississippi river don’t reach this far from shore, leaving the ocean clear. The familiar, cavernous blue of deep water stretches below, occasionally probed by a wavering beam of sunlight that has pierced the armour of the slick above. For as far down as I can see, there are tiny specks glinting in the shifting light, while others lurk as shadows behind.
Yellow-brown haloes surround the light when it appears from above, its fringes dotted as though by a swarm of motionless insects. Ten feet below this haze, I force my eyes to focus close to my mask. A shred of the slick hangs in the water in front of me, the size of a snowflake, but one that is a lurid, toxic brown. Inches beyond it are more of them, melted into a variety of ghoulish shapes. The chemical dispersants being sprayed from the air are dragging the oil away from the surface in scraps, and now they are arrayed in sinister formation, the largest hovering just beneath the underside of the slick, the smallest way below. In British waters, a sight like this would mean plankton, evidence of a huge bloom of new life. Here in the Gulf, it looks like death.
Looking up, my stomach lurches. I can no longer see the waves above. If I come straight up now, I’ll be coated in the poisonous sludge. The previous day, I’d spoken to one of the local spear-fishermen who ply their trade in among the rigs. He’d decided to see what had become of his hunting ground, but had become fouled in thick oil; immediately, his skin had begun to burn.
The suspected cause of death for many of the 250 or more turtles and 30 dolphins that have so far washed up is either acute toxicosis or “forced submergence”. Most had no external evidence of oil on their bodies. The US authorities say that they are still in crisis mode and have not yet had time to analyse the tissue samples that would tell us more, but I can now see how, for an air-breathing creature, fear of coming to the surface could lead to death by drowning.
I’m in the water with Dr Susan Shaw, director of the Marine Environmental Research Institute and an expert in the toxicology of marine mammals. We had both wanted to see for ourselves what was happening beneath the slick, so had hunted down an edge where clear water ran alongside. Shaw estimated that a five-minute exposure should leave us unscathed. With eyes, ears and noses shielded and all exposed skin smeared with a barrier of Vaseline, we’d slipped in through a rainbow-coloured sheen beside the spill.
Rising towards the black underbelly of the slick I see light, and swim towards it.
Back on the deck of the boat, Dr Shaw and I sit in silence for a minute. I’d always thought of death by oil as life being smothered by a thick coating of sticky, black ooze. That was happening here as slicks reached shore, suffocating marshlands and killing birds. But out at sea, beneath the surface, a different kind of disaster was developing. In the Gulf of Mexico spill, it’s what we can’t see that’s going to hurt most.
Beyond the immediate physical impacts of oil are the slower-acting toxic effects, Shaw tells me. There are thousands of organic compounds in oil, some of which attack reproductive and central nervous systems. The “light sweet crude” surrounding us is a particularly volatile mix, containing noxious compounds that quickly evaporate into the air. “Oil also contains PAHs: polycyclic aromatic hydrocarbons,” says Shaw. “Once they work their way into the cell, they get into the nucleus, then insert themselves into the DNA. When it’s time to reproduce, things go wrong, setting off the cell’s automatic repair mechanism. The cell tries to copy it again and again, and gets stuck in a loop. That’s cancer.”
But what has spooked Shaw more than the oil is the spectre of what has been sprayed on the oil to keep it from reaching the valuable – and highly visible – coastlines. The dispersants are designed to break up the oil and lessen the physical damage. Unfortunately, they have an environmental cost of their own. BP initially responded to the growing spill by spraying Corexit 9527 containing 2-butoxyethanol, a chemical that ruptures red blood cells when ingested. “When it was sprayed over the Exxon Valdez spill in 1989, workers suffered health problems, including blood in their urine, and liver and kidney disorders,” says Shaw.
She goes on to explain that its replacement, Corexit 9500, contains compounds that are acutely toxic to invertebrates, and can cause chemical pneumonia if aspirated into the lungs following ingestion. By the time this magazine went to press, more than one million gallons of dispersant had been sprayed on to the slicks. What we’d seen beneath the slick hanging in the water was a toxic cocktail of light sweet crude and dispersant, masquerading as plankton. As soon as it was ingested by grazing fish, it would start a journey from the body of prey to that of predator, and on up through the food chain, getting more concentrated at every step.
Over the horizon, a city of ships were still trying to plug the gushing wellhead. Exactly how much oil was coming out was impossible to say; no one had devised an accurate way of measuring it, and BP was unwilling to let anyone try. Later, when a temporary cap was finally put in place, 10,000 barrels of oil were being piped to the surface every day and still the escaping flow was overwhelming the equipment on the seabed. Even by lower estimates, the quantity had already exceeded the quantity spilled from the Exxon Valdez, yet the extent of the problem on the surface still appeared small in comparison.
More than three weeks after the accident, a research vessel announced that it had detected a huge underwater plume of oil. Oil is lighter than water and should rise to the surface, and both the National Oceanographic and Atmospheric Administration (which had funded the project) and BP’s chief executive tried to downplay the plume’s existence. But experiments conducted off Norway in 2000 (and co-sponsored by BP) predicted that such plumes would form if oil escaped in deep water. Only between 2 and 28 per cent of diesel released from 800 metres actually reached the surface. Add the fact that by early June BP had injected some 300,000 gallons of Corexit 9500 at the wellhead to try to disperse the oil at source, and it seems likely that what’s being seen at the surface is a small fraction of what is spreading through the deep.
“It’s a giant chemistry experiment,” says Shaw. “No one has ever used these dispersants on such a scale before and never in such deep water. We just don’t know what the effects are going to be.”
The deep sea is a hard place in which to gain scientific knowledge. It is a three-dimensional world determined by shifting fronts and wavering currents, and it is difficult to interpret the changes observed there. In most areas of the ocean, the expense is also crippling, but that is one advantage that the Gulf does boast.
“The flora and fauna of the deep of the Gulf of Mexico are better known than almost anywhere else, thanks to the oil industry,” says Professor Robert Carney, a deep-sea ecologist from Louisiana State University who has studied the Gulf for 40 years. “They have to prove they’re not setting up platforms on delicate areas like deep-sea coral beds.
“But almost nothing is known about the sensitivity of the deep sea to an event like this,” he continues. “Creating such high-pressure conditions is difficult in a laboratory, making experiments impossible.”
There have been fascinating glimpses of this undiscovered – and endangered – world. A recent seabed survey found some 700 new species of crustacean in an area the size of a small bathroom. Meanwhile, in the water above, giants await. Scientists have recovered a single giant squid from the deep water near New Orleans, but they assume that more must be there, providing prey for the resident pod of sperm whales. To try to find out more about what impacts the spill might have already had, Dr Tim Shank of the Woods Hole Oceanographic Institution in Massachusetts is preparing to visit some deep water coral beds that he has studied before. Oil will kill these corals at certain concentrations, but it is the sub-lethal effects – such as reduced fertility – that will be much harder to measure, says Shank. What’s more, with so many variables at play in the deep, it may turn out to be hard to show any direct evidence that the Deepwater Horizon disaster is to blame.
“If we see damage to corals and plants, we can’t say what killed them without more forensics,” Shank continues. “We’ll be taking a certified contractor on all our studies, who will fingerprint any traces of oil we find. That way they can tell if it’s from that well.”
Oil fingerprinting – based on the particular mix of compounds from a specific well – could help determine causation in some cases, but not where marine life has been affected by dispersants, and where there are no remains to be found there is nothing to fingerprint.
Much depends on the flow of currents in the deep, but even in the well-studied waters of the Gulf they are little understood. A fleet of sea gliders – a silent, underwater version of the drones circling above Afghanistan – has been dispatched to investigate the deep workings of the Loop Current that some fear will sweep the oil through the Florida Keys and its fragile shallow-water coral reefs.
Satellite images have already shown patches of slick on the surface being carried away, but what happens below is far more significant. Shallow-water coral reefs may be even more sensitive than their deep water cousins to the toxic cocktail in mid-water. Invisible and unstoppable, it would be giving residents of both Florida and Cuba sleepless nights if they knew about it. So far, however, the data from the gliders suggests that contamination of the Loop’s lower reaches has not occurred, says Shank.
Other currents will also soon make themselves known. Every year, surges of cold water rise from the Gulf’s deep water. Elsewhere in the world, these upwellings deliver vital nutrients that fuel new life on the continental shelves. In the Gulf of Mexico they will be delivering tar balls, rolling them uphill along the seabed towards the shore. Florida residents erupted in panic at tar balls on their beaches in mid-May, but these were remains from earlier, smaller leaks and spills. For the coming decades, every year the cold upwellings will deliver a fresh consignment from the deep, and most will surely bear the chemical signature of Deepwater Horizon.
Of course, oil is no stranger to the Gulf of Mexico. Earlier, while our boat tore at high speed through the prized wetland marshes of Venice, Louisiana, every few minutes we’d pass a tangle of pipes and valves.
Nearly 4,000 oil and gas platforms are scattered across the Gulf to tap reserves that are so widespread they ooze from the seabed. Known to scientists as “cold seeps”, they were first discovered here in the Gulf. Clustered around these spots, communities have grown up on the seabed that use hydrocarbons, not sunlight, for energy. Some have suggested that, given time, the bacteria that feed on oil could be relied upon to clear up the spill.
“Colonies of oil bacteria are patchy, and something this size could be overwhelming,” says Shank. “Even if they could handle the quantity, these animals would end up taking all the oxygen out of the water.”
The Gulf of Mexico is already home to one of the world’s largest low-oxygen dead zones, a shifting and fragmented area where there is not enough oxygen for animal life to survive. This dead zone waxes and wanes with the seasons, but can engulf as much as 8,000sq miles of sea, an area about the size of Wales.
Fertiliser from intensively farmed land drains into the Mississippi and then into the ocean where it feeds a bloom in microscopic algae, then a secondary bloom in microscopic animals. While fish are usually nimble enough to escape, life on the seabed itself often can’t.
There are already suggestions that de-oxygenation is happening in the water column in the area of the underwater oil plumes. Scientists say this is likely to be caused – to some extent, at least – by a boom in oil-eating bacteria.
Although the Gulf was still one of America’s richest fishing grounds before the Deepwater Horizon accident, scientists have argued for years that it’s a highly stressed ecosystem. So far it has managed to resist a decades-long siege by overfishing and the chronic pollution from oil and agriculture. But total ecosystem collapses have happened before, and no one can say quite what it will take to push the Gulf of Mexico over the edge.
“Everyone’s worried about the oil hitting the marshes and the tourist beaches,” says Shank. “But there are also lots of sea-floor ecosystems. They cycle our nutrients and support the fish we go on to eat. There are vulnerable marine ecosystems down there that will take a long time to recover – tens or hundreds of years. We don’t know if they’ll ever come back.”
Sitting at the helm of our boat in the shadow of Rig 313, Captain Mike Ellis isn’t convinced that the Gulf is in trouble. “I came down here seven years ago from Barbados because this is the best fishing in America. Take size, number of species, availability, you won’t find better – and our rates reflect that,” he says. What’s more, Ellis, a tall, broad, ex-US Navy man who hides his face from the sun in a balaclava, says the oil industry should be thanked for making the fishing what it is. “The only reason there are so many fish here is because of these rigs. The fish love them. This is where we take all our clients, and where I helped them get three world records,” he says, his voice slightly muffled from behind the fabric. “The states that don’t allow drilling, they’re making a mistake. They’re missing out.”
He urges me to go and take a look. Ribbons of oil slick are threaded through the legs of Rig 313, but when a clear patch opens up, I slip into the water. The massive structures tower above me, supporting a dense cluster of piping and converted shipping containers throbbing with the sound of a large generator. Looking down, the closest leg to me stretches towards the seabed 300ft below.
Taking a cautious, shallow breath, I fin down the leg. Suddenly a large fish – some sort of jack – emerges out of the gloom. Then another. I’m surrounded by cobia, amberjack, red snapper, mangrove snapper and barracuda, many of them easily 4ft long. It’s one of the biggest groups of large fish I’ve seen in nearly 20 years of diving.
Rigs make good artificial reefs. Stretching from the seabed to the surface with lots of nooks and crannies, the shelter they offer creates vibrant marine communities. The fish look healthy; ecologists later confirm that there is no reason to think that they would be in trouble yet.
But looking closer at this shelter – the enormous rig leg in front of me – the barnacles near the surface are clogged with oil. It’s just a matter of time before the chronic, toxic effects of the oil and the chemicals being used to keep it from the surface start accumulating in the tissues of these enormous fish. How long depends on how far up the food chain they are, but for these fish it could be a year or more.
But Ellis is not looking that far forward. He’d be happy with proper compensation for the time lost to the closure of the fishing grounds. The $5,000 (£3,400) he’s received up to now hasn’t gone far towards making up the $20,000 a month he says he usually takes.
“We’re not mad at the oil company as long as they take care of us. We need the oil – I need it to put in my tank,” he says, patting one of his twin 200hp outboard engines.
Soon we’re roaring back to shore, Ellis trying to find clear water in order to clean the dirty brown tidemark of oil from his gleaming white hull. He doesn’t manage it.
Dr Shaw and I peel off our suits and wash ourselves down. We don’t seem to have been affected, but over the next few days both of us develop a mysterious cough, similar to that appearing among the clean-up workers on shore. Is this a mild dose of the chemical pneumonia that may have killed the dolphins and turtles? It’s impossible to say.
“Bodies are going to start appearing,” shouts Shaw over the din of the engines. But a mass slaughter of fish seems unlikely. The chances are that the chronic toxicity of this spill will not result in corpses but in a lack of young life. As the cancers cascade down through the generations and the seas grow empty, the trail will have gone cold.
A few years down the line, expectations will have been eroded and time will have blurred the blame.
Without knowing what was there before, and without science sensitive enough to gauge its influence, we’ll never know exactly how much has been lost in the Gulf of Mexico due to the events of April 22, 2010.
The slow passage of pollution
Marine food webs are sometimes traced using the flow of energy that passes through them. It starts with the sun, the ultraviolet rays of which are captured by algae in the upper waters. The energy then passes through a succession of animals, ending at the top-level predators, or perhaps straight into an enormous grazing herbivore like a baleen whale or a whale shark.
A morbid open-water experiment has now effectively been unleashed in the Gulf, tracing the food web via the cocktail of chemicals in the oil and the dispersant. But while 90 per cent of energy is lost when one organism eats another, the toxin accumulates as the bigger fish eat the numerous small ones they need to survive.
Plankton, the drifting organic soup that fills the sunlit upper waters of the Gulf of Mexico and every other productive patch of sea, is the first stage to be affected by the oil. It is made up of algae, microscopic animals, tiny invertebrates, larvae and more, but the composition depends on time of year, water conditions and location.
Most plankton will simply die if exposed to enough oil, but what happens next depends on what was in this soup. If fish have been spawning in the area – as the highly endangered Atlantic bluefin tuna have been – then an entire year could be lost. Dispersed into specks the oil may be ingested directly through the cell walls, or by the tiny animals that normally eat algae or the fish that eat plankton. Once inside a living body, some toxins will start to poison while others are stored away in tissues as a toxic time bomb.
Eventually, these will reach the very top of the marine food web, to the swordfish, wahoo, tuna and snappers so prized by game fishermen and restaurateurs. In waters closer to shore, filter feeders such as shellfish and shrimp accumulate them directly. At the end of the food chain, they end up in our own fatty tissues, waiting for the moment when those reserves are broken down before they are released into our systems.
The Gulf of Mexico was the first place where life was found to be fuelled by hydrocarbons seeping from the seabed, a community that did not rely on light as its energy source. Here, the specialised mussels, clams and marine worms survive by consuming bacteria, which in turn feed on hydrocarbons slowly seeping from the seabed. As they are acclimatised to oil, these could be more resilient, yet may still be overwhelmed by the sheer quantity of oil in the waters of the Gulf. Like so many of the organisms in the lower reaches of the sea, their reaction to the chemical dispersants is wholly unknown.
What’s the worst possible outcome?
A poisonous mist swirls over the water, threading between the rusted legs of the remaining rigs. The waves are thick with the reds, browns and greens of the algae that are releasing the gas. Below, the fish that made the Gulf of Mexico famous are gone.
The algae are not the ones that the microscopic animals that once thrived here were used to, so the grazers died off. Without the tiny animals to eat, the plankton-eating fish disappeared. It was only a matter of time before the bigger fish went, too. The dolphins and whales vanished soon after.
Jellyfish now rule the sea, their alien pulsing replacing the quiver and twitch of fishes’ fins. Drifting dead zones of deoxygenated water suffocate the few survivors, while layers of exotic oil products lurk at different depths, separated out like liqueurs in a lethal cocktail. On the seabed, dead colonies of deep-water corals still reach into the current with skeletal fingers. Where patches of oxygen remain, 3ft-long isopods like prehistoric cockroaches roam the seabed scavenging the poisoned life that falls to the seabed.
This apocalyptic vision of one possible future of the Gulf of Mexico is unlikely, but its chances of coming true grow with every barrel of oil that spurts from the wellhead and every gallon of dispersant injected. Some 50 million barrels of oil lie in BP’s Macondo Prospect oil field, a quantity that, at even the fastest rate, would take at least seven years to finish pouring from the seabed.
It will surely be sealed completely long before then, but with a system as large and as complicated as the Gulf’s, it is impossible to say quite how it will react to the enormous body blow it has already been dealt. Forty years ago, more than three million barrels poured into the Gulf of Mexico after the Ixtoc 1 blowout – the largest accidental spill in history. A handful of years later, few effects could be seen. But add overfishing, the enormous existing dead zones and pollution to any residual effects of Ixtoc 1, and you have a more fragile system.
For decades the Black Sea was battered by overexploitation and pollution, until in the late Eighties a jellyfish species invaded and the entire ecosystem collapsed. It has since begun to recover. We’ve never seen a system as large as the Gulf of Mexico go over the edge. Let’s hope we never do.
No comments:
Post a Comment