Oil has fueled industry from the late nineteenth century, and oil spills have been with us since then. But they only really grabbed the headlines when they happened at sea, an inevitable consequence of offshore drilling and shipping. Much of the oil taken from the North Sea when I was young came from rigs in less than three hundred feet of water. As these wells were drained companies looked farther offshore, and deeper. Drilling has now moved off the shallow continental shelves into the deep sea. If you push the limits of technology, problems are inevitable, as we learned on April 20, 2010, when disaster struck BP’s Deepwater Horizon rig in the Gulf of Mexico while boring a well a mile down. Human error and slapdash attitudes to safety led to a blowout that turned the rig into a fireball. Eleven people were killed and many more injured.1 For BP, this was only the beginning of their troubles.
Capping a well a mile below water, they discovered, is not like capping one at three hundred feet. Early on a camera was placed on the seabed beside the wellhead. Over the following months, as BP executives writhed in the limelight, the camera beamed images into homes across the world of a violent geyser of oil and gas spewing into clear Gulf waters. While BP tried to play down the size of the spill, the camera showed the well gushing sixty-eight thousand barrels per day,2 exposing their mendacity. The oil poured out relentlessly for months, as BP tried one trick after another, spreading hundreds of thousands of gallons of chemical dispersants, and at one point even stuffing the well full of old golf balls (some wits suggested that oil executives would have been a better choice). Spring turned into summer, and the spreading deep-sea oil plume burped slicks to the surface that washed ashore on beaches and marshes from Texas to Florida. In another BP gaffe, turtles trapped behind containment berms were immolated in the fires that were set to prevent oil from coming ashore. Eventually something worked, and the gush was choked off on July 15, eighty-six days and an estimated ten tanker loads3 of spilled oil later (roughly 4.4 million barrels, after an estimate of oil retrieved is subtracted).
Deepwater Horizon taught us several things. We now know how much harder it is to contain a spill at depth than in the shallows. And we know that we are extraordinarily unprepared for problems at the deepening frontier of oil and mineral exploitation. BP’s risk assessments for the rig detailed how walruses and sea lions would be protected in the event of a spill, an obvious cut-and-paste job from an Arctic plan! In fact, the company was shockingly unprepared. It didn’t possess any specialized equipment to control a deep-sea blowout. The plan might as well have said, “If something bad happens, scratch your head for a while and wonder what to do.” Or, as a friend once said to me, “When in danger or in doubt, run around and scream and shout.”4
The disaster also taught us that spilled oil doesn’t always bubble to the surface, as everyone expected. Plenty of oil did appear, and an area the size of Cuba was covered by sheen for months; but most of it remained out of sight as it spread in a giant plume far below. For more than a month BP executives and some government scientists denied its existence, but repeated studies showed it was there, and that it remained there long after the well was capped, together with seven hundred thousand gallons of chemical dispersant that BP injected at the leaking wellhead.
I first discovered that not all oil floats when, as a newly minted PhD, I took a job as a reef scientist in the Egyptian town of Sharm-el-Sheikh. Soon after I arrived a cargo ship hit a reef and spilled hundreds of tons of fuel, which washed ashore in stinking globs. Apparently, the technical term for this kind of oil is “chocolate mousse,” and it certainly had that look. Beneath the waves, puddles of thick oil darkened the seabed, where they slopped around for the next year or two, until they became so covered in sand and bits of sea grass they vanished. Some is probably still there today.
In 1979, there was another massive well failure in the Gulf of Mexico, Ixtoc 1, which was being drilled by the Mexican oil company PEMEX. It gushed oil near the Mexican coast for over nine months. With an estimated half million tons spilled, Ixtoc held the record for the world’s largest oil disaster until Saddam Hussein’s deliberate environmental sabotage in the Arabian Gulf during the first Gulf War. Thirty years on you can still dig lumps of oil from mud around the stems of mangrove trees near the site of the Ixtoc spill. The oysters that used to crust the trunks and roots of the trees disappeared soon after the accident and have never recovered.5 We don’t know much about the long-term impact of this spill, because once the oil was no longer visible, money for research dried up. If we had kept up our interest we would know a lot more now about what to expect from the Deepwater Horizon spill in years to come.
There is a limit to what we can learn from past spills about what to expect from Deepwater Horizon. Until now our experience has been of surface spills, in which floating oil either evaporates, breaks down at sea, or ends up on beaches. There is no precedent for oil injected into dark, cold, deep-sea water at high pressure. The Deepwater blowout could have profound effects on deep-sea life. Soon after the spill the seabed nearby was covered by a thick flush of microbes that feasted on the carbon bonanza. Later measurements showed a virtually dead bottom, which suggests either that it was too much of a good thing or that dispersants killed them. As of now, we still don’t know. While the two million gallons of dispersants almost certainly helped limit oil impacts onshore, they might also trigger a breakdown of the food web. Dispersant increased the oil exposure of miniscule plankton and thereby the creatures that eat them by breaking it into tiny droplets. Some scientists fear that the poisoning of plankton and microbes will interrupt nutrient cycles, perhaps leading to eventual starvation of top predators like sperm whales and dolphins. We know that the bodies of tiny plankton in the Gulf are already contaminated with dispersants, and it is worrying that there was a spike in bottlenose dolphin miscarriages in the aftermath of the spill.
Oil spills are the starkest of all human impacts on the sea: dark, suffocating, inexorable. Images of seabirds struggling through blackened waves are shocking, but in most cases oil is not the worst of their concerns. The toll of seabirds and marine mammals tangled up and drowned by fishing gear is far greater than from oil spills.6 The Gulf of Mexico’s fishing fleets kill more marine life in a day than Deepwater Horizon did in months. After the spill, fishing was banned in many parts of the Gulf. When the fleets were allowed to return several months later, catches were plentiful after the brief and salutary respite from fishing.7 The environmentalist Carl Safina wrote of how many commentators called Deepwater Horizon “the worst environmental catastrophe in American history,” but to his mind, the spill was far less disastrous than the twenty to forty square miles of marshland eaten from the Mississippi delta every year by sea-level rise and subsidence, and engineered defenses that starve the delta of life-sustaining mud.8
Some of the most iconic oil spills of the past have been from ships, like the Exxon Valdez in Alaska’s Prince William Sound or the Amoco Cadiz off Brittany, but today the main risks of large spills are from drilling and pipelines. Pipeline spills have increased more than fourfold since the 1970s, partly because so much more oil is pumped today, but also because many pipelines are aging.9 And yet as Deepwater Horizon has underscored, the real problem is our expansion of the oil industry out into the inky deep. Companies can now tap oil far beyond their capacity to contain a spill when things go wrong.
Back in Egypt in 1987 I asked an expert what he thought was the best way to clean up the brown gloop that smothered the shore in front of us. “A bucket and spade,” he answered. Low-tech methods may still be the best we have, but the fried turtles from the Gulf of Mexico remind us that they aren’t very effective. The best thing for the planet, of course, would be to wean ourselves off oil, but that is unlikely to happen any time soon. In the meantime, governments must demand much higher standards of safety and greater investments in prevention from oil companies.
Oil companies are easy to demonize, but the biggest source of oil pollution in the sea is not from tanker spills or c
areless drilling, but from people like you and me. Two thirds of the oil spilled into the sea around North America is carried with runoff from land (from dumped engine oil, fuel, and industrial leaks) or introduced directly by pleasure boats and jet skis.10 The great majority of recreational boats have two-stroke engines. They are cheap, light, and powerful, but these assets come at a high cost to the environment. A quarter of the fuel-oil blows straight through the engine into the sea. (Many scooters use two-stroke engines, which is why they leave you choking on a cloud of oil and gas as they pass.) The floating fuel and oil concentrate at the sea surface, and wrap around and poison the floating eggs and hungry larvae of hundreds of species. I find it extraordinary that we continue to tolerate such profligate polluters when alternatives exist. Four-stroke engines have a closed system, so they emit ten times less pollution than the cleanest two-stroke motors. It is time to call time on two-strokes.
Oil has actually had a few benefits for wildlife. The highly visible impacts of spills helped galvanize the creation of some of the first marine parks, much as logging spurred the establishment of national parks on land in the late nineteenth century. The Great Barrier Reef Marine Park in Australia and Monterey Bay National Marine Sanctuary in the United States came into being this way. But away from hellish scenes of burning sea and turtles dripping tar, pollution’s most insidious effects in the ocean come from chemicals we can’t see.
In the late nineteenth century, chemists managed to synthesize organic compounds—chemicals that contain the element carbon—with some very useful properties. (All organic compounds contain carbon, but not all carbon-containing compounds are organic.) These compounds were extremely durable, would not burn easily, did not conduct electricity, and were resistant to sun and weather. Chemists called them polychlorinated biphenyls, but most people know them as PCBs. Naturally people quickly thought of many things they could do with these new wonders, and industrial-scale production began in the 1920s. They were put in glue and hydraulic fluids, used as plasticizers in paint and as heat and fire retardants in furniture, and formed the plastic coating of electrical wires, among other things. There was just one drawback, which by the 1970s could no longer be denied: They were also highly toxic, causing cancer, liver damage, skin lesions, and a catalog of other horrors.
The problem began when manufacturers discharged PCB-laced effluents into rivers, lakes, and estuaries, and chimneys disgorged them into the skies. Once inhaled or eaten, PCBs are not broken down, and they tend not to be excreted. They are highly lipophilic, or fat-loving, which means that they are stored in the fat of animals that ingest them. When big animals eat smaller ones they take on much of their load of toxins; so PCBs bioaccumulate through the food web from prey to predators. In the U.S. Great Lakes, for example, PCB concentrations in predatory herring-gull eggs reached fifty thousand times higher than in lake plankton from the base of the food web. In the 1970s, the carcasses of emaciated seabirds laden with PCBs began to wash ashore.
PCBs are just one class of chemicals among a wide range that are collectively known as persistent organic pollutants, or POPs for short. They include compounds like DDT, introduced to the world as a wonder pesticide in the 1940s—and which lost its gleam when it was found to cause hatching failure in birds and alligators. DDT had decimated birds of prey and fish lovers like the brown pelican before it was banned in the United States in 1972. Other countries soon followed.
In the 1960s and 1970s chemists were shocked to discover traces of DDT, PCBs, and other persistent organic pollutants in polar ice. The poles seemed so remote and pure, their landscapes carved from crisp, clean snow and ice, their skies sharp and clear. How was it possible? Pretty easily, it turned out. Sea and air know few boundaries and can carry chemicals to the most inaccessible corners of the globe. Smoke from Chinese coal plants crosses the Pacific to North America in less than a week. Currents also move pollution, although at a more sedate pace. They transport chemicals thousands of miles in months or years. Unfortunately, certain properties in the makeup of the oceans mean that persistent chemicals find a much faster route to the poles.
Between the ocean and the air is a thin layer of water whose properties are very different from that of the sea beneath.11 At around one four-hundredth of an inch, this layer is not much thicker than a piece of plastic wrap. This thin membrane is stabilized by surface tension and rich in fats, fatty acids, and proteins; it is the reason why the surface of the sea sometimes has a glassy smoothness. Its stability attracts and concentrates microorganisms, floating eggs, particles of dust, and other materials. Unfortunately, water repelling, fat-loving compounds like POPs accumulate in this “surface microlayer.” There they reach concentrations much higher than in the underlying water, often tens or hundreds of times higher.
When storms tear the sea into driven spray, contaminants race across the oceans and can bluster inland to drench coasts and people. Pollution in one region, such as the South China Sea, can leapfrog in a series of storm-whipped aerosols to far-flung regions. In this way, with the help of the wind, remote regions like the central Pacific can become polluted even if they seem to be beyond the reach of serious contamination.12 Storm spray can leap barriers like the south polar current that circles the Antarctic and separates it from the rest of the ocean. Once pollutants have reached the poles they are swiftly taken up by animals there and work their way up the food chain.
The poles accumulate POPs through a second kind of hopping, known to chemists as the grasshopper effect. Many POPs are semivolatile, which means they evaporate and condense within the range of seasonal temperature variation. In summer the chemicals evaporate off sea and land and blow around in the atmosphere, until temperatures drop sufficiently for them to condense, and they get redeposited. This happens either as the season changes or they reach somewhere cold at higher latitudes or on mountaintops. Chemicals are trapped within or under ice at the poles, and the year-round low temperatures mean little is lost by further evaporation, so contaminants accumulate.
The surface microlayer is critical for microscopic life. Fish eggs and larvae concentrate in the top millimeter of the sea, where they benefit from better feeding conditions or escape from predators like jellyfish. Invertebrates, such as crab or sea urchin larvae, can be up to ten times more abundant in the microlayer than in underlying water, while microalgae may be ten to a hundred times more common and bacteria a hundred to ten thousand times.13 There they come into intimate contact with toxic contaminants. Animals feeding in the microlayer will take up pollutants and pass them up the food chain.
Persistent organic pollutants differ in an important way from oil pollution. Although they are invisible, in the long run they are far more dangerous to marine life. Oil and gas have been around since time immemorial. Natural seeps in places like the Gulf of Mexico have leaked from the seabed for millions of years. What to us is toxic and unpleasant is food to vast numbers of microbes. Deepwater Horizon jetted an enormous plume of methane into the deep sea. Before long, a bloom of methane-degrading microbes (our ancient friends) had formed around the leak and within a few months had degraded much of it to harmless carbon compounds and water.14 Toxins such as DDT, PCBs, and many pesticides are highly complex, and the pathways of breakdown are much longer, which is why they hang around causing trouble for so long. In the extreme North and South Atlantic these pollutants are sucked into the deep sea on the global ocean conveyor current. At the icy polar extremes of the planet, where the weather is cold and the sun weak, they resist breakdown far longer than in warmer climes.
The daily adventures of a group of bottlenose dolphins in Florida’s Sarasota Bay have been followed by scientists since the 1970s. Their world closely intertwines with that of thousands of people who use this seaway every day for business and leisure. The dolphins enjoy a carefree life frolicking in the waves close to people who live or vacation in Sarasota. In reality they experience as close to an urban lifestyle as any animal in the sea, and that is stressful. Florida is one
of the most populous states in America. It supports its share of heavy industry and chemical production, as well as agriculture dependent on lavish applications of agrochemicals. The emerald gleam of Sarasota Bay is not as pure as it seems.
Tissue samples taken from the bay’s dolphins show that they carry a heavy burden of contaminants.15 They are at the top of the food web, and toxins passed from below stop with them. There is a troubling difference, however, between males and females. The toxic load carried by males increases over their lives. The most contaminated animal found in the bay was a dead forty-three-year-old male. His flesh would probably have been condemned as hazardous waste had officials known its chemical content when they disposed of the body. Toxins in females peak in adolescence and then plunge to much lower levels that remain stable until later life. The difference between the sexes is explained by pregnancy and breast-feeding.
Pregnant dolphins, and all mammals for that matter, including ourselves, experience high energy demands from their growing babies. If food is short, they must mobilize fat reserves to cope, which means that accumulated toxins are liberated into the bloodstream and passed on to the developing fetus. After giving birth, they continue to transfer toxins by lactation. Around 80 percent of toxic contaminants in female dolphins are passed to their first-born calf. Not surprisingly, these calves fare badly. Only half survive their first year, compared to 70 percent of calves born subsequently. We can’t blame all of this on the chemical brew that mothers feed their offspring. By definition, first-born calves have inexperienced mothers who may also be smaller than older mothers. But there is a link. In a group of captive dolphins held by the U.S. Navy, mothers whose calves died within twelve days of birth had about two and a half times more PCBs in their bodies than those whose calves survived.16
The Ocean of Life Page 15
