How Temperature Affects Deep Sea Coral Recovery From Exposure To Pollutants

How Temperature Affects Deep Sea Coral Recovery From Exposure To Pollutants
Lophelia pertusa and a squat lobster. Photo courtesy of Dr. Erik Cordes/Lophelia II Project

March 18, 2020

Lophelia pertusa is one of the only reef-building deep-sea corals found below 200 meters. These corals lives in a number of deep-sea ecosystems around the globe. They and provide vital habitat for many deep-sea species. Unfortunately, these corals are threatened by human-caused stressors in to their environment, including the impacts of oil and gas extraction as well as warming and more acidified waters caused by global climate change. They are also abundant in the Gulf of Mexico and there is potential that they had contact with oil that was spilled during the Deepwater Horizon accident in 2010.

Researchers wanted to understand the direct impacts of these stressors on the health of L. pertusa, so they collected live coral specimens from the Gulf of Mexico and brought them back to aquariums at Temple University in Philadelphia, PA. From there, they exposed the corals to a combination of pollutants and stressful environmental conditions, in order to better understand how they reacted to and recovered from these stressors. Corals were exposed to oil, chemical dispersants and oil + dispersants, while also experiencing warmer than normal water temperatures and decreased pH (more acidic) levels. 

Lophelia pertusa lab specimen. Photo courtesy of Alexis Weinnig

It was discovered that L. pertusa had a particularly negative response when exposed to chemical dispersants, like the ones that were used to mitigate the Deepwater Horizon spill. The corals also had a hard time recovering from exposure to the dispersant when under thermal stress (in waters warmer than they typically experience). The corals were not negatively impacted by exposure to only oil however - the ecosystems these corals typically inhabit exist near oil cold seeps (places where oil and gas naturally seep out of the sea floor) meaning that these corals might already to used to small amount of oil being in the surrounding water. 

These deep-sea corals are an important animal that lives in many deep-sea environments, including the Gulf of Mexico. They are a vital habitat for other animals and play a large role in the function of deep-sea ecosystems around the globe. Many coral species were impacted directly by the oil spilled during the Deepwater Horizon accident, but this new research shows that dispersant application also played a large role in impacting the health of L. pertusa and possibly other corals as well. This research provides further evidence that dispersants, meant to be helpful and minimize impact, actually did more harm than good to the biological communities in the Gulf.

To read the entire study, you can find it online here.

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