Where has the oil gone?
By Dr. Samantha Joye
Professor, Marine Sciences, University of Georgia
The Gulf Oil Blog
Published: August 1, 2010 3:26am
The Deepwater Horizon wellhead that tapped the Macondo reservoir was capped on 15 July 2010. After the venting of oil and gas into the Gulf waters was stopped, everyone felt a sense of relief. Multiple news outlets have reported that the surface oil has disappeared, for the most part. I read many reports that stated conclusively the oil had been either transferred to the atmosphere (via evaporation) or that it had been consumed by oil-eating microorganisms. Everyone’s reaction was, not surprisingly, ‘what a relief !!’.
Should we be relieved? Is this disaster over?
On the whole, I believe the answer to both questions is no. It is a relief that the volume of surface oil is reduced, as this lowers the probability of oil-fouling of coastal beaches and marshes. However, it’s likely that a great deal of oil is still out there in the Gulf of Mexico’s waters, it’s just no longer visible to us.
While some of the oil has most certainly evaporated, much of it was dispersed and this oil is still floating around, invisible to our eyes, within the ocean’s water column. Some of the oil has probably sedimented to the seafloor, where it is also invisible to our eyes. The fact that this oil is “invisible” makes it no less of a danger to the Gulf’s fragile ecosystems. Quite the contrary, the danger is real and the danger is much more difficult to quantify, track and assess.
And, what about the dissolved gases, mainly methane? Very few measurements of methane concentrations have been made and very few people are thinking about methane’s potential impacts on Gulf deep waters. We, and a couple of others, have measured remarkably high methane concentrations in the water column. Its oxidation, and the microbial growth it fuels, will influence oxygen and nutrient budgets in the deepwater.
What about the dispersants? Where have they gone and what is their impact in the system? How are dispersants influencing the organisms that call the Gulf’s waters, beaches and marshes home? We do not know the answers to these questions but we need to know.
The impacts of the oil, gas and dispersant on the Gulf’s ecosystems will be felt for years, if not decades. We cannot pretend the danger has passed for it has not. Additional and on-going studies of open water, deep seafloor, and coastal dynamics are necessary. We must be diligent and we must insist that long-term monitoring programs be established and maintained so that we can evaluate and insure the recovery of the Gulf’s ecosystems.
Questions posed to the Gulfblog
1. Have microbes eaten most of the oil in the Gulf?
We don’t know. I have not seen any data reporting measurements of microbial oil degradation rates in the Gulf’s surface waters since the spill started and I’m not aware of anyone making such measurements. My group measured oxygen and methane consumption rates but not oil consumption rates per se. So, concluding that microbes have consumed all the oil would be impossible.
2. Will microbes eat the dispersants being used?
We don’t know this either. There have been no reports of dispersant degradation in situ in the Gulf waters since the spill started. There have been reports of dispersants in larval crabs so it is getting eaten. It’s unclear how “biodegradable” the corexit is however so we don’t know how long it will persist in the environment.
3. Was the characterization of your interview in the article fair?
This question refers to THIS... story. My words were taken somewhat out of context. I said that we know there are elevated rates of microbial activity in the deepwater plumes but we don’t know if this activity is stimulated by oil, by gas, or by both. We did not measure oil degradation rates per se.
4. Is BP buying off scientists?
I know some very good people who are doing research that is funded by BP so I don’t think it’s fair to say that BP is buying scientist’s silence in a general sense. Yes, some scientists have been asked to sign confidentiality agreements but they are given a choice about this. Believe it or not, some good research is funded by BP but those things do not usually make the newspapers. I have heard the stories of getting people to sign confidentiality agreements and I think that’s a bad thing, in general and especially in a case like this. It will be interesting to see if those [confidentiality] agreements are voided or relaxed now that the issue is getting so much bad publicity.
5. Is NOAA giving data to BP and not our public university scientist?
I do not know the answer to this question. I know that the data BP is generating is flowing freely to Unified Command (NOAA/USCG/EPA) but not to university scientists. The JAG reports HERE... contain some of the data generated by BP funded vessels (i.e. the R/V Brooks McColl). In general, I feel data should be more freely exchanged between the academic and federal/BP scientists and I feel that we need much more coordination and cooperative planning between academic and federal/BP scientists. There needs to be more central coordination in terms of what is being measured, where and when.
6. Are any professors or scientist at UGA working for BP?
Yes, a couple are but I don’t know the conditions of their contracts. My offshore work is funded by the National Science Foundation and NOAA.
7. How dangerous are the methane levels in the Gulf?
The methane concentrations in the Gulf’s deep waters are extremely high. The hazard posed by these high gas levels is that oxygen consumption will be stimulated and oxygen concentrations could become depleted. At this point, very few measurements of methane concentration have been made so we cannot say with certainty how high widespread the elevated methane levels are.
8. Is the air quality around the Gulf nothing to worry about?
I have not seen enough data to make a conclusion about this. I can tell you that when I was out there, the air quality was terrible (made me cough) when we were near areas of active burn-offs. Evaporation of oil into the atmosphere and potentially dispersants or dispersant by-products getting into the atmosphere could reduce air quality substantially. Once more, more data is needed before sound conclusions can be made.
9. Had you seen these pictures of millions dead bait fish and do you think it was oil, corexit, methane or low oxygen or all of them?
Fish kills happen without oil, corexit and methane. Determining the cause takes sleuthing and time. I have seen the pictures and it is tempting to link such events to the spill but we need data to do that and I have not seen convincing data making that link but I know studies are underway to make those linkages.
10. Are you’ll still able to publish your data to the public, and when?
No one is preventing us from publishing. It usually takes 4-6 months to write a paper after collecting and analyzing the data. I have already submitted on paper (it is in review) and I have another paper on the oil spill that will be submitted in a couple of weeks. When the papers are published, I’ll publish links to them on the blog.
11. Are there other leaks on the gulf floor near the main leak we see on the cams?
I have seen images of what looks like new seeps near the wellhead but it is difficult to say whether this is from natural seepage or whether it’s related to the blowout. Time will probably tell. Right now, it’s too early to say.
12. Has BP sprayed 43 million gallons of Corexit instead the 1.5 million they reporting?
I think it will be some time before we know the full scale and impacts of the dispersants used to manage this spill. I think it’s safe to say however, that 43 million gallons of corexit have not been used because the stockpile of corexit was not that big and the production capacity is limited. We can come up with the upper application limit by knowing those two things and it’s much closer to 5 million gallons than 40 million gallons.
What’s next?
We’re heading back out on August 19th. We’ll be out for about a month. We will doing some far field work (>50 miles from the wellhead) and we’ll work in the plume area for a couple of weeks.
Bi-Monthly Press Conference.
I will be conducting one more press conference (August 10th) before we leave for the cruise. The media advisory for the weekly press conferences will be available on the resources page of the blog
