Fifteen years after the devastating Deepwater Horizon oil spill poured an estimated 134 million gallons of oil into the marine environment, vital long-term monitoring work involving University of Hawaiʻi at Mānoa oceanographers continues to chart the slow path to recovery for the region’s deep-sea coral communities, providing critical information to guide their restoration. The marine organisms, living at depths of 1,000 to 2,000 meters, were directly impacted by the largest offshore oil spill in U.S. history.
In October, two oceanographers from the UH Mānoa School of Ocean and Earth Science and Technology (SOEST) participated in the latest expedition that revisited monitoring sites off Louisiana. The team’s mission was to capture new images of more than 200 individual coral colonies using a remotely operated vehicle equipped with high-resolution still and video cameras.
“Processes in the deep ocean are very slow,” said Fanny Girard, assistant professor of oceanography at SOEST and lead investigator in the project. “Many of these animals look exactly the same as they did in 2011. Itʻs a sobering reminder that recovery in the deep sea takes time.”
High-tech imaging
The first phase (2011 to 2017) of this work aimed to evaluate impacts to deep-sea corals to inform the Natural Resource Damage Assessment process. Following the 2016 settlement with BP Exploration & Production, the second phase of this work is now informing restoration by providing critical baseline information on coral health, growth and role as habitat for many other species.
Teams took images of the same locations each year, and Girard and her graduate student Jack Howell manually compared the photos, a demanding process that can take hours for a single coral colony.
“We’ve learned that lots of animals, particularly brittle stars, live on these corals,” said Howell, whose project is focused on associations between coral and other organisms. “This seems to be a ‘win–win’ collaboration, where the brittle star may receive food and shelter, while the coral benefits from the brittle star potentially eating parasites and cleaning up sediment that could compromise its health.”
