Animal populations in the deep northern Gulf of Mexico fell sharply after the 2010 Deepwater Horizon blowout and have shown little recovery, according to a study published Monday in the Proceedings of the National Academy of Sciences and reported by Wired¹.

The paper found that groups including octopus, krill, squid and shrimp declined by 60 to 85 percent in the three and a half years after the spill, with krill and lanternfish among the hardest hit¹.

Researchers described the drop as the fastest and most severe faunal decline reported for Earth's largest ecosystem type and said lingering effects may also reduce the ocean's ability to move carbon dioxide from the atmosphere to the deep sea¹.

After considering other factors such as water temperature and oxygen levels, the authors identified the blowout as the most parsimonious explanation for the collapse, Wired reported¹.

A Transocean drilling rig working for BP about 50 miles southeast of the Mississippi Delta exploded on April 20, 2010, killing 11 people¹. Oil and gas flowed from a well nearly a mile deep for 87 days, releasing about 4.9 million barrels of oil and about 7.7 billion cubic feet of gas, and agencies authorized about 1.84 million gallons of chemical dispersants, according to the account¹.

Lead author Tracey Sutton of Nova Southeastern University said prey patches that large predators need have disappeared¹. "We haven't seen a sperm whale in 10 years," Sutton said, according to Wired¹.

The team compared a 2011 baseline with surveys from 2015 to 2023 across a grid around the spill site, from about 650 feet below the surface to about a mile down, using depth-stratified nets, noon and midnight sampling, and shipboard echosounders¹.

Bruce Robison of the Monterey Bay Aquarium Research Institute, who was not part of the study, told Wired the work was comprehensive and that he knew of no other study with such a large number of net samples¹. Jeffrey Drazen of the University of Hawaii at Manoa said net, acoustic and genetic lines of evidence corroborate one another¹.

The authors wrote that the findings also bear on proposed deep-sea mining, which they said could damage ecosystems before baseline conditions are assessed¹. Natural resource damage assessments and restoration work continue; BP agreed in 2016 to a $20.8 billion settlement that included up to $8.8 billion for environmental restoration, Wired reported¹.

Sources

1. WiredOil Spills Wreak Havoc on the Bottom of the Ocean, Even a Decade Later6:30 AM

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