Research Amplifies Coral Worries

Source: The Royal Gazette

Bermuda’s coral reefs could be indirectly impacted by the 2010 BP Deepwater Horizon Oil Rig explosion that saw millions of gallons of oil leaked into the ocean — ironically not by the oil, but by chemicals used in the clean up.

This came from Dr Gretchen Goodbody-Gringley, a scientist at the Bermuda Institute of Ocean Sciences (BIOS) who conducted groundbreaking research into the effects of the spill shortly after it happened, at the Mote Marine Laboratory in Florida. Dr Goodbody-Gringley is currently a scientist at BIOS. Results of the study have just been published in the peer-reviewed journal ‘PLOS ONE’.

In the wake of the disaster which saw 760 million litres of crude oil released into the ocean, BP company officials and environmentalists rushed to spray chemicals known as dispersants on the oil slick to break up the oil and sink it into the ocean. In the end, they used 200,000 gallons of dispersant. Dr Goodbody-Gringley’s research has found that this may have been a case of the cure being worse than the disease.

“The dispersant doesn’t actually reduce the amount of oil, but it breaks up the slick so that the oil sinks into the water column and makes it less visible on the surface,” said Dr Goodbody-Gringley. “What is important about that is that the oil actually did less damage on the surface. The study I did was looking at the oil without any dispersant in it compared to oil that did have dispersant and then just looking at dispersant alone. We found that the oil itself is not great for larvae, but has to be in rather large concentrations to have an effect. If that dispersant chemical is combined with the oil then it is extremely damaging.”

Bermuda’s coral reefs depend on larvae (baby corals) from this general area. Some Dr Goodbody-Gringley’s PhD research was looking at dispersal of larvae from the Caribbean to Bermuda.

“There is in fact some connectivity between the Caribbean and Bermuda,” she said. “If the coral populations in the Caribbean were decimated it would definitely have an effect on us in the long term. That would mean we are solely dependent on self recruitment from corals that already live here. So I think because the entire Caribbean is connected as a whole we function as one. If something happens negatively in one area, eventually it could reach a distant location such as Bermuda.”

Luckily, Bermuda is not in close vicinity to any oil drilling, so we would probably never feel the direct impact of an oil spill. Places like the Florida Keys are very close, especially now that Cuba plans to start drilling for oil right next door to the Florida Keys.

Her conclusion is that ultimately, if an oil spill occurs close to a coral reef, it would be best not to use a dispersant chemical. Her research suggested that a better way to clean it up would be skimming the oil off the surface of the water, or using controlled burns.

“It is better to just remove the oil altogether rather than trying to disperse it within the water column,” she said.

She said previous research into oil spills focused on the “cute and fuzzy” creatures that were affected by the oil such as birds and mammals, creatures with more screen appeal than a coral polyp.

“You see it on the news, seals or birds covered in oil,” she said. “A lot of research goes into studying the effects on those types of animals, but there is limited research into things such as corals.”

There have only been two or three other studies looking at the effects of oil and dispersant on marine life. This was the first study to look at how the oil and the dispersant would effect coral recruitment or juvenile individuals.

“At the moment, the oil is relatively cleaned up,” she said. “There is still ramifications of it in the water column because it was consumed by some organisms. It passes down the food chain that way. A few studies have found that the oil spill has impacted the bacteria in the water. When you are talking about the oil effecting the smallest creatures in the ocean obviously that will have ramifications all the way up to the largest. It goes up and up and up. There are likely long term effects but they are still being studied at this point.”

So far, three years after the accident, Bermuda corals have not shown signs of suffering and it is unlikely that oil from this accident will reach Bermuda. If there were to be any outcomes for Bermuda’s corals we wouldn’t see it until several years after the spill. Possible outcomes we could see from oil exposure are a slow down in the growth and reduced overall well being of the reef.

She said BP themselves have funded several studies into the effects of the spill.

“Hopefully, the research that we have just published will help inform decision makers in the future,” she said.

At BIOS she is working with other scientists at BIOS to study ocean acidification and climate change. She is interested in studying the genetic diversity of Bermuda’s coral reefs, and is looking for funding for such a project.

Read Dr Goodbody-Gringley’s paper on the PLOS ONE website at dx.plos.org/10.1371/journal.pone.0045574