National Geographic : 2010 Oct
• But on the ocean side of the reef, where winds and waves and currents were stronger, no oil remained. The lesson for Louisiana and the other Gulf states is clear, Tunnell thinks. Where there is wave energy and oxygen, sunlight and the Gulf 's abundant oil-eating bacteria break it down fairly quickly. When oil falls to the bottom and gets entrained in low-oxygen sediments like those in a lagoon---or in a marsh---it can hang around for decades, degrading the environment. Fishermen in the nearby village of Antón Lizardo hadn't forgotten the spill either. " e Ixtoc spill about destroyed all the reefs," said Gustavo Mateos Moutiel, a powerful man, now in his 60s, who wore the trademark straw hat of the Veracruzano shermen. "Octopus gone. Urchins gone. Oysters gone. Conch gone. Fish almost all gone. Our families were hungry. The petroleum on the beach was halfway up our knees." ough some species, such as Bay of Campeche shrimps, recovered within a few years, Moutiel, along with several other sher- men who had gathered on the beach, said it took 15 to 20 years for their catches to return to nor- mal. By then two-thirds of the shermen in the village had found other jobs. Even in the turbulent, highly oxygenated wa- ters of France's Breton coast, it took at least seven years a er the 1978 Amoco Cadiz spill for local marine species and Brittany's famed oyster farms to fully recover, according to French biologist Philippe Bodin. An expert on marine copepods, Bodin studied the long-term e ects of the spill from the grounded tanker. He believes the impact will be far worse in the generally calmer, lower- oxygen waters of the Gulf, particularly because of the heavy use of the dispersant Corexit 9500. BP has said the chemical is no more toxic than dish- washing liquid, but it was used extensively on the Amoco Cadiz spill, and Bodin found it to be more toxic to marine life than the oil itself. " e mas- sive use of Corexit 9500 in the Gulf is catastrophic for the phytoplankton, zooplankton, and larvae," he says. "Moreover, currents will drive the disper- sant and the oil plumes everywhere in the Gulf." In May, scientists in the Gulf began tracking plumes of methane and oil droplets dri ing up in court to preserve a moratorium on deepwater drilling until such time as it could be deemed safe. "In some cases I'm not con dent that the industry is tapping these resources safely," says Bea. "We can expect more of these in the future." B seemed on the verge of plugging the Macondo well permanently with drilling mud and cement. e fed- eral task force's estimate of the amount of oil released stood at 4.9 million barrels. Govern- ment scientists estimated that BP had removed a quarter of the oil. Another quarter had evapo- rated or dissolved into scattered molecules. But a third quarter had been dispersed in the water as small droplets, which might still be toxic to some organisms. And the last quarter---around ve times the amount released by the Exxon Val- dez---remained as slicks or sheens on the water or tar balls on the beaches. e Deepwater Hori- zon spill had become the largest accidental spill into the ocean in history, larger even than the Ixtoc I blowout in Mexico's Bay of Campeche in 1979. It is surpassed only by the intentional 1991 gulf war spill in Kuwait. e Ixtoc spill devastated local sheries and economies. Wes Tunnell remembers it well. e tall, 65-year-old coral reef expert at Texas A&M University--Corpus Christi earned his doctor- ate studying the reefs around Veracruz in the early 1970s, and he kept studying them for a decade a er the spill coated them with oil. Tun- nell wrote an early report on the impact there and on Padre Island in Texas. In early June, a er the new disaster had once again raised the ques- tion of how long the impact of a spill can last, he returned to Enmedio Reef to see if any Ixtoc I oil remained. It took him three minutes of snorkel- ing to nd some. "Well, that was easy," he said. Tunnell stood in the clear, waist-deep water of the protected reef lagoon holding what ap- peared to be a three-inch-thick slab of sandy gray clay. When he broke it in two, it was jet black on the inside, with the texture and smell of an asphalt brownie. Here on the lagoon side, where the reef looked gray and dead, the Ixtoc tar mat was still partially buried in the sediments. When oil falls to the bottom, into the mud of a lagoon or a marsh, it can hang around for decades, degrading the environment.