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Oil Spills Wreak Havoc on the Bottom of the Ocean, Even a Decade Later
This story originally appeared on Inside Climate News and is part of the Climate Desk collaboration.
Across hundreds of miles of the northern Gulf of Mexico, a deepwater ecosystem collapsed after the massive 2011 Deepwater Horizon oil and gas spill, and recovery is uncertain, new research concludes.
The study, published Monday in the Proceedings of the National Academy of Sciences, found that animal populations—including octopus, krill, squid, and shrimp—declined by 60 to 85 percent in the three and a half years after the spill, with few signs of recovery since. Krill and lanternfish, both foundational species in the Gulf’s food web, were among the hardest hit. The findings also suggest that the die-off is causing genetic bottlenecks that could further hinder ecosystem recovery.
The researchers identified it as the “fastest and most severe faunal decline reported for Earth’s largest ecosystem type” ever documented. The widespread die-off of marine organisms may also reduce the ocean’s ability to transport carbon dioxide from the atmosphere to the deep sea. After ruling out other factors, such as water temperature and oxygen levels, the researchers identified the Deepwater Horizon blowout as “the most parsimonious explanation” for the ecosystem’s collapse.
Comprehensive natural resource damage assessments and restoration efforts involving federal, state, and tribal trustees are ongoing. In 2016, BP agreed to a $20.8 billion settlement, including up to $8.8 billion for environmental restoration.
Remote ocean depths and habitats miles below the surface may seem buffered from the impacts of human activity, the authors wrote, but their findings suggest an industrial disaster pushed part of it into a diminished state with “limited resilience to facilitate recovery.” They said their findings also show that proposed industrial deep-sea mining could damage the ecosystem before baseline conditions are assessed.
A transoceanic drilling rig, operating for BP about 50 miles southeast of the Mississippi Delta, exploded on April 20, 2010. The explosion and fire killed 11 people and triggered the largest accidental marine oil spill in history.
Oil and gas spewed uncontrollably from the broken well nearly a mile deep for 87 days, ejecting 4.9 million barrels of oil at a rate of about 400 tanker trucks per day, enough to fill up 1.2 million cars. The spill also released about 7.7 billion cubic feet of fossil gas into the deep sea at a rate of 88 million cubic feet per day, enough to supply about 820,000 US homes. State and federal agencies, including the Environmental Protection Agency, also authorized BP to apply 1.84 million gallons of chemical dispersants to try to reduce the impacts.
Some of the oil and gas dissipated and was transported out of the deep Gulf of Mexico region. Some coated barrier islands and devastated coastal wetlands and shellfish habitat, and some settled onto the ocean floor, where currents can stir it back into the water. But enough hydrocarbon and chemical-dispersant remnants stayed suspended long enough to do almost immeasurable harm.
A series of studies since the spill have shown a wide range of toxic effects on marine organisms, from impaired development and reproduction to increased mortality and lasting health problems in dolphins and whales. The new paper suggests that lingering pollutants may interfere with some species’ ability to find mates in the dark by disrupting their highly developed sense of smell.