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Wed March 28, 2012
ECU Study Finds Oil From the Deep Water Horizon Spill Enters Food Web
New Bern, NC – It's been almost two years since the Deep Water Horizon oil spill in the Gulf of Mexico. On April 20th, 2010, the semi-submersible Mobile Offshore Drilling platform exploded, killing 11 workers and injuring 16 others. Oil continued to gush out of the well for more than 80 days, causing an oil slick so large it could be viewed from space. The Deep Water Horizon incident is being called the second largest environmental disaster in the United States. Since the incident, researchers have been trying to understand how the oil from the spill affects the ocean food chain. Professor in the Biology Department and the Institute of Coastal Science and Policy at East Carolina University, Dr. David Kimmel says a team of students and faculty took a trip to the Gulf coast just after the spill to collect samples of zooplankton
"zooplankton have a very important function in the food web because they sit right at the interface between the lowest part of the food web, which is phytoplankton and these are analogous to plants on land and these animals fix carbon and they form the base of the food web. Zooplankton feed upon these phytoplankton and therefore repackage that energy and material into a form that fish can eat. These are primarily fish that are larvee and so they will eat the zooplankton and then they will grow into larger size fish that we may eat sometime in the future."
In August 2010, about a half dozen researchers from ECU teamed up with three other universities in the United States to collect samples in the Gulf. After analyzing the samples in the winter and spring, the researchers found that the zooplankton samples showed evidence of contamination from the oil spill. Dr. Siddhartha Mitra is a professor in the department of Geological Sciences at ECU.
"the zooplankton samples that we collected . These are small planktonic animals primarily crustaceans showed evidence of contamination of what we call polycyclic aromatic hydrocarbons which are one of the chemical constituents of the oil itself."
Basically, the study, published in the February issue of Geographical Research Letters, showed there were minute amounts of the polycyclic aromatic hydrocarbons present in the zooplankton. Another key point of the study sought to develop a "finger print" of the polycyclic aromatic hydrocarbons in the oil. This helps scientist determine that the oil came from the Deep Water Horizon oil spill, as opposed to other sources.
"The oil by itself has thousands of chemicals in it. Some of these chemicals are harmful and some of them are not so harmful. One of the things about this oil spill was to be able to get a quote on quote "fingerprint" of the spill. And one of the things we saw right away is we had collaborators with the U.S. Geological Survey who provided us with actual oil from the leaking riser pipe below the surface of the ocean and they also provided us samples of oil slicks from the surface of the ocean."
Upon analysis of the samples, they were able to determine the Deep Water Horizon's unique chemical signature in oil leaking from the riser pipe and the surface slicks.
"we compared those with samples from Santa Barbara and some samples from surface slicks, and from the Deep Water Horizon riser pipe as well and that way we were able to look at a bunch of different samples and see if the signature of what we found in the zooplankton matched that of the Deep Water Horizon oil spill or if it matched something from a more natural source or some other source of oil that we were unable to pinpoint. "
One of the surprising findings from the study is that zooplankton samples collected far away from the leaking wellhead showed signs of contamination, while samples collected closer to the site didn't have the chemical fingerprint.
"the effects of the spill were sort of patchy in the ecosystem. In other words, it wasn't directly related to where you how far away you were from the actual leak"
The presence of oil contamination, even if it's a trace amount, has some worried that the seafood they are eating is unsafe. ECU Biology Professor David Kimmel suggests avoiding oysters, shrimp and crabs that come from marshy areas in the Gulf of Mexico. But says seafood caught off the coast of eastern North Carolina should be safe.
"Not a lot of oil actually very little oil at all was able to make it up into the eastern part of North Carolina to affect our beaches/ So I don't think there is much danger from contaminated seafood in this particular region."
A study is underway at ECU to gauge the potential impact of the BP oil spill on the eastern North Carolina coast. Last year, researchers collected zooplankton samples in Onslow Bay shortly after the oil. They'll compare those with the "fingerprint" from the Deep Water Horizon oil spill to see if the seafood is contaminated with the oil from the Gulf.
We're analyzing the samples right now. Some of the same students were involved in both collecting the samples and analyzing them and we hope to have the information done the analysis done in the Spring and then I have to do some statistical analysis and then we hope to release those results sometime over the summer."
While he doesn't expect to find any traces of oil from the Deep Water Horizon spill in the local food web, Mitra says they hope to establish a base line chemical signature of the zooplankton taken from Onslow Bay to compare to later in case there are any oil spills off the coast. Jared Brumbaugh, Public Radio East.