One question that remains six years after the BP oil disaster in the Gulf of Mexico is how the use of dispersants affected the Gulf ecosystem. To find out, Thursday morning WMNF News interviewed David Hollander, a professor of chemical oceanography at the University of South Florida College of Marine Science. He was chief scientist on several of the first studies of the BP disaster. His team tracked oil in the water and sediments and how it affected the ecosystem.
Listen to the full interview here. Video is below.
One of the things I was reading is that you were finding that the oil is settling in the sediments.
“With the Deepwater Horizon, it being the first deep-sea blowout, there were a lot of new things that had never been discovered. Which, from a scientific point in spite of the sober aspect of the blowout and the number of people killed, was that there were a lot of new paradigms to write for science. And some of them included the subsurface plume.
“But, one of the outstanding, more long-lived results that we found was that oil was actually came up to the surface and then turned around, with a process, and ultimately sedimented down on the floor of the northern Gulf of Mexico, on the continental shelf and on the slope.”
Is that because of the marine snow or something else?
“Well, yeah it was a marine snow event, but, in marine systems you constantly have particles that are settling down. But, this was–and we’d name the term “flocculant blizzard”–because indeed what had happened was the oil and the dispersant were interacting with the algae, when they opened up the flood gates of the Mississippi and the diversionary channels to push the oil off shore, a lot of clay minerals and nutrients came out with it. And as a consequence of that, the oil bound with the clay minerals; the dispersant caused the oil droplets to decrease in size, making them more bio-available, but, at the same time the algae with their nutrients were blooming and they would secrete a mucousy material, to essentially create a buffer between the contaminants and their cell walls and that material was very sticky.
“So, you had this perfect storm of the clay minerals, the nutrients, the algae, the oil and the dispersants aggregating together, coming together, binding together and then, because of the clay minerals, they were able to sink to the sea floor–very rapidly.”
A recent paper in the journal Proceedings of the National Academy of Sciences of the United States of America is titled Chemical dispersants can suppress the activity of natural oil-degrading micoroorganisms.
“The jury is still out. Some microorganisms, you can’t group them into one single bin. There are many, many microbes that actually actively degrade oil. Some prefer the dispersant; some prefer the oil. It seemed to be that the two together created a little bit more of a toxic mix than one had anticipated. But, the microbes did a pretty good job of degrading the simple compounds. But, petroleum is made up of over 70,000 compounds, some quite complex and those still remain.”
So what lessons, as far as dispersants go, for if there’s another marine oil disaster like this, should people use dispersants?
“Again, it’s a fairly complex issue because there was dispersant deployed and applied out to the surface of the ocean. But, for the first time in history, it was actually injected into the oil blowout itself, out in the deep sea.
“So, on the surface, it helped to cause this marine snow event and so people should be cautious of that. In the deep sea, there is a lot of argument about whether or not it actually did anything. The aspect of the oil coming out but, oil and gas–which is what they call “live oil”–has a much different behavior than does pure liquid oil. And so the dispersants, they didn’t regulate whether or not the plume was going to form-it formed. It may have increased some of the concentrations of it, decreased the droplet size and ultimately made it a little bit more biologically available. So, it’s a real debate right now.
“The surface application of dispersants is used for decades and if you’re trying to help the first responders that are there, it might be better. If you are looking at the long-term impact for the ecosystem, that might not be the best choice. But, the application at the well-head itself, that’s still very much of a debate. And now is the time where you have experimental work that is done under high-pressure, such as, the work that we are doing in Hamburg, where we can actually simulate those pressures, those temperatures, those flow rates with live oil and see what the impact of those dispersants are.”
You’re calling for more baseline studies. First of all, for someone who is not a scientist, what is a “baseline study” and why is that important?
“A baseline study is characterizing the circumstances, the components, prior to an event. So, if you want to really understand what the–quantitatively in hard terms–what was the impact of an event, you have to know where you were before that event occurred. And that’s what they refer to as the “baseline.”
“And in the Gulf of Mexico, there were–sadly–very few baselines available, for many different components that were affected by the spill. And that’s why, as scientists, you are always hedging your bet of what impact occurred and how severe was it, because, we never had the kind of baselines that we needed.”
The AP reports:
An environmental group is suing the Interior Department for the “fast track” permitting of potentially dangerous oil and natural gas wells in offshore waters. The lawsuit filed Wednesday by the Center for Biological Diversity seeks to force regulators to conduct more in-depth environmental reviews of drilling plans before handing out permits. The suit was filed on the sixth anniversary of BP’s catastrophic oil spill, which started with a blowout of a deep-water well on April 20, 2010. Eleven workers were killed and millions of gallons of oil spewed into the Gulf of Mexico. The California-based group filed the suit in federal court in Washington, D.C. The Bureau of Safety and Environmental Enforcement is the Interior agency that oversees drilling. A spokesperson says the bureau is reviewing the suit.
Some groups are calling for a moratorium on deep drilling. As a scientist, you probably don’t want to weigh in on the politics of it, but, from a standpoint of the health of the ecosystem, what would you say?
“Well, I think the reality is is that we are hydrocarbon-driven society. The fact is, is that there is an increasing tendency for the industry to move into deeper and deeper and deeper water. About 40% of the oil recovered out of the Gulf of Mexico, today, is from ultra-deep wells. The engineering is phenomenal. They are very capable, very proficient at what they do.
“The interesting aspect is that these events occur very rarely, but, when they do occur, that’s when there’s the possibility for catastrophic impacts to the ecosystem. They’re drilling now in over 2 miles of water, about 5,000-6,000 meters. The Deep Water Horizon was about 1,500 meters. So, indeed in the Gulf of Mexico, it’s quite common to see wells at 2 miles of depth, so somewhere on the order of 3,000 meters depth. And the question is: If something happens, how do you plan to shut it off? Obviously, it’s too deep for any divers to go down, so it all has to be done remotely with remotely operated vehicles and through electronic communications. And so, this is a debate.
“There is an argument of whether you want to do fracking; is that better than deep sea exploration? And that’s a debate for the policy people. But, there’s a lot that could be improved upon in the deep sea exploration and production.”
What do we know about the safety of seafood?
“Yeah, well the safety of seafood is probably better than it ever has been, in the context that more eyes are watching. The testing is very rigorous. There are parts of the fish that still continually show contamination, whether that’s chronic or a relaxation from acute event, that’s still to be debated. It’s principally in the liver and in the gull bladder, and those you shouldn’t be eating anyway. If you do the testing of the muscle it looks perfectly good.”
And deformities that we’ve seen in Gulf organisms, do you think that might related to the BP spill?
“Well, I think that’s our largest fear, is that there’s actually genetic alteration of the next and following generations. And this is why you can’t rush to judgement to say that: The Gulf has restored itself and its resilient. Things happen and they have to work their way through the ecosystem, which may be generational. And as a consequence, 6-8 years down the road things may be showing up as problems that you would not think originally happened.
“Such as in the Valdez, it took 4 years for the herring fisheries to collapse, after the Valdez. After the Valdez, fishing went on like it never had, like in the Gulf. And the question is: What is the long term impact? So, I think that’s the thing that we’re most fearful of, is that these impacts will result in genetic alterations which then affect generations to come.”
Finally, there’s still a lot of science that you’re doing now. What are the biggest questions that you have yet to answer and you’re still trying to look at right now?
“How long will petroleum stay in the system? How long will it take for a lot of these benthic deep sedimentary ecological communities-how long will it take for them to recover? That’s pretty much the largest consequence. And, of course, the genetic implications.”
Since you brought up the deep benthic communities. What’s that like? Most of us have never been there, what are those communities like and how have they been affected?
“So, they form the basis of some of the food-web, for the fish for example, that live off of food off the bottom. Some of them live on the bottom and some of them burrow into the bottom. So, if these organisms that actually are the food source for the fish, continually take up contaminants, then the fish will be contaminated.
“I think what we’re seeing though is, initially there was a die-off because of the marine snow or the flocculant blizzard effect and now their coming back. It took 3-7 years approximately. That’s what we’re seeing.
“We’re able to judge that and compare it because there was actually another spill that happened in the Gulf of Mexico back in 1979 called the Ixtoc spill and in our last funded proposal we go down to the southern Gulf of Mexico, to the Bay of Campeche where the Ixtoc blowout occurred and take sediment cores and evaluate how long it took for the benthic system there to recover.
“We saw the same kind of phenomena as a marine snow blizzard effect that had occurred down in Mexico and we estimated that it was somewhere less than a decade that it took the system to recover. So, we can have the same expectation for the northern Gulf of Mexico. Especially considering that the communities are almost identical to each other.”
Leave a Reply
