The BP Oil Plume

By John Conway | August 20, 2010 1:55 pm

This past week has seen a lot of news stories about a “Manhattan-sized” plume of oil found in the Gulf of Mexico by researchers near the site of the BP Deepwater Horizon well. This sent my BS detector into the yellow zone, so I have been trying to get a better idea of just how much oil remains in the Gulf from this disaster. It’s definitely not gone.

So I went to Wikipedia. There, you can find a reference to a New York Times article from the beginning of August, where the total volume of the leak was estimated to be 780,000 cubic meters of oil. Now, that’s clearly in the category of “reasonable guess” – no one knows for sure. But it is very unlikely to be a factor of two larger or smaller than that, so let’s just use that for now. There are a lot of other uncertainties, for example the amount of natural gas (methane) that came out with the oil, how the flow rate changed with time, and so on. But again, let’s just ignore those.

How big is 780,000 cubic meters? Simply taking the cube root of this number, this is the volume of a cube 92 meters on a side. It would look something like this next to the Pentagon:


I can imagine two reactions to this comparison: 1) Damn, that’s a lot of oil! 2) That’s tiny compared to the volume of the Gulf of Mexico! (I bet one’s political views might play a role in which reaction comes first…)

If we were to take this volume and spread it out in a layer 1 millimeter thick, it would cover an area of 780 million square meters, which is a square about 28 kilometers on a side. The satellite images of the oil slick showed affected regions much larger than that, from which I conclude that the thickness of the surface layer must have been much less than 1 millimeter at those times. (But check my math, somebody!)

If all the oil were dissolved uniformly into the Gulf, which has a total volume three million billion times the size of the leak, the concentration would be about one third of one part per billion. That’s an interesting number all by itself, and not at all as small as it seems. But not all the oil leaked is in the Gulf – much of it evaporated and a good deal has been consumed by bacteria. But the rest of it went somewhere, right?

Now to the underwater plume. In the abstract of the Science Magazine paper that led to all the news stories, the authors said “Our findings indicate the presence of a continuous plume over 35 km in length, at approximately 1100 m depth that persisted for months without substantial biodegradation.” I cannot find the word “Manhattan” anywhere in their article, and so I have to conclude this was some mainstream media (WSJ?) person’s rather inept attempt at putting the size of the plume into perspective. It was parroted endlessly in the media as if it had meaning. In fact it’s quite misleading – clearly the term “Manhattan-sized” conjures up images of the whole island of Manhattan along with all the tall buildings…but as we have seen the total volume of oil leaked into the Gulf is about the size of one of those buildings.

So what is this plume? The authors define it as “a discrete spatial interval with hydrocarbon signals or signal surrogates (i.e., colored dissolved organic matter or aromatic hydrocarbon fluorescence) more than two standard deviations above the root-mean-square baseline variability.” That is, a place in the water where there is clearly oil present at detectable levels. It can be at quite low concentrations and still be detectable. One of the article’s main findings was that “Gas chromatographic analyses for only monoaromatic hydrocarbons of several water samples gathered using survey guidance confirm benzene, toluene, ethylbenzene, and total xylenes (BTEX) concentrations in excess of 50 μg L–1 within the plume at 16 km downrange from the well site.” This is all bad stuff we don’t want in the water or getting into the food we eat.

I assume a lot more scientific research will need to be done to know the actual damage that the presence of these oil components will do to marine life, the fisheries, and the food chain. The authors took a stab at making an estimate of how much oxygen depletion was occurring due to biodegradation of the oil, concluding that “it may require many months before microbes significantly attenuate the hydrocarbon plume to the point that oxygen minimum zones develop that are intense enough…to threaten Gulf fisheries.” That’s good news for marine life, I assume, but means that the subsurface oil will take quite some time to be bioegraded, which is bad in the longer term. So why hasn’t the media talked about that aspect of the article?

There is no question that this was a huge amount of oil leaked into the Gulf and that the impacts will be felt for many years to come. It is an epic disaster by any measure and may have consequences no one has considered yet. But we have to be rational about the real impacts of the disaster, and rational about the real risks involved in deep water drilling. The only way is to continue vigorously the kind of research we saw in the Science Magazine article, and debate the findings openly. BP needs to release publicly everything it knows about the spill.

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  • Tim Lewis

    Sounds like an apologist for a rape and pillage industry/culture, minimizing the impact of this massive assault on our environment.

    Hey mathematician, you know the volume of oil that was puked out into the ocean is a fraction of the gas that was injected into it right?

    Do you know the Hydrogen Sulfide, a large part of the oil and gas that is produced in the sour crude in the gulf kills people at just over 15 parts per million in the air.

    I wonder how the sea life and corral reefs in the gulf like that 780,000 cubic meters of sour crude, twice or three times as much cubic meters of poison laden gas and millions of gallons of dispersant that was dumped in there.

    Unlike humans who survive a poisoning, the gulf isn’t going to get a holiday from the constant saturation of poison that we subject it to. It has to suck it up and keep taking the same amount we’ve been crapping into it before this massive dose.

    This wasn’t small, relative to anything. It was like a massive nuclear bomb going off in one of our most fertile fisheries.

  • John

    Did you read the whole post, Tim Lewis? Calm down. I mentioned the methane – read again. As I said, at the end (which you clearly did not reach) “this is an epic disaster by any measure and may have consequences no one has considered yet.” This includes the long term effects on life forms of all kinds in the Gulf. There was already an enormous “dead zone” at the mouth of the Mississippi due to the toxic agriculture runoff of the entire midwest, so it may be hard to tell what killed what.

    The whole point is that we need to consider what happened, how it happened, and what will happen as a result rationally, based on facts. Irrational, emotional reactions such as yours will only get us deeper in the you-know-what.

    And, rationally, we may conclude that deep water drilling is just not worth the risk. We came damned close to fracturing the sea bed, in which case the entire oil field could have eventually leaked out into the Gulf before we could stop it. I read one estimate that this would have been a total release of oil a thousand times greater than this. We dodged that one, but we need assurance that this can not and will not happen in the future before we continue to drill in deep water, or in shallow water for that matter.

    Funny, when I wrote a post over a year ago urging continued high quality research and rational thinking about global warming and the consequences, I was raked over the coals in the comments for being an apologist for the oil companies. I even got invitations to attend oil-company-funded seminars and conferences, at their expense. I doubt this post will generate any of those…

  • Haelfix

    Good article and much agreed.

    One of the hardest things to get across to laymen is the concept of scale, which can often lead to a tremendous amount of confusion.

  • Tim Lewis

    Calm down John, I read your whole post. You make a case that it just might not be as bad as we all think. That maybe it’s worth the destruction. That more research is needed before we can conclude exactly how bad it was, so let’s not rush to judgment right?

    Well, when a person throws a fast food bag out of their car, I don’t need an Environmental Assessment to conclude it is socially irresponsible. And the idea that “it was already dead so what is the problem?” is the same cynical excuse that industry has been making for decades to avoid responsibility for their actions. “we already sterilized that stream so what’s the problem continuing to pump pollution into it?”

    Your little article will be quoted and promoted by people defending the oil industry and what they have done and continue to do, because it makes an argument in their defense. Is that not what you intended?

    Look at Haelfix’s comment here. “well said, those ignorant laymen just don’t understand scale”. If you don’t know your little argument here is defending the oil industry and the culture it prospers from then maybe you should re-read your article.

    To the scale issue, imagine a little tiny thimble, lets put something in it like say sulfuric acid (a common part of this sour crude oil). It’s just a little tiny thimble, in scale it’s nothing to the human body right? Will you be first to drink the thimble John? Maybe Haelfix would? It’s just a little tiny thing compared to your great big body right?

  • Per

    John, you’re identified with the Obama administration.

    In trying to defend it, this becomes something that can be used as an excuse for a corporate industry that’s been raping the earth of its resources for decades.

    What is more, if you want to ponder something, perhaps you should ponder what the consequences of BP enormous political influences (which undoubtly was demonstrated the last few months) over the current administration are (and the past administration also for that matter, this is above the illusionary right / left issue) .

    I think its time for the scientific community to wake up to the fact that the Obama administration is exactly as bad as the prior one. Sure, it looks better, talks better and definitely is more charming. But the mantras of the election was change, hope and so on, but exactly which policies changed? Bombing women and children under the name of war on terror, ignoring the constitution and wall streets (or major corporate) influence is exactly the same now as under the Bush administration. Before it was at least obvious that the leaders were corrupt, now theyre the same, but they give the impression their not.

    By the way, thanks Tim. You wrote a very nice comment(s).

    Cheers, Per

  • RBH

    This post is a slightly more sophisticated version of a recent post on a local web board a few weeks ago, where a lawyer (!) calculated that the amount of oil leaked from the Deep Horizon accident was tiny when compared with the total volume of the Gulf and therefore worrying about it was silly and/or just liberal hysteria. But of course, he neglected to consider a few pertinent variables, like localization of the leaked oil, persistence of the leaked oil, toxicity of the leaked oil and associated substances, and differential susceptibility of the various inhabitants of the Gulf to the leaked stuff.

    And you did the same thing, John, just a bit more scientificy-sounding. I expect better from you.

  • John

    Its amazing how people can read what you write and infer that you mean something totally different that what you actually said. Everyone brings their own biases and prejudices to interpreting any text, clearly. But I find the above astounding.

    Tim, no, I did not make the case that it might not be as bad as we think. Read again.

    In fact, I think there may well be a strong case to completely suspend any new ocean drilling for oil, despite the insatiable thirst for it that the global economy has. The argument against it is that the possibility of an ultra-catastrophic event such as the leak of an entire oil field into the ocean, however small the probability, is just too damaging to allow to happen.

    The point of my post is that these researchers’ fine work was rather grossly misinterpreted by the media, and endlessly parroted elsewhere without thought. And what we need is thought, and vigorous research, and rational debate. The shrill, emotional, financially and politically driven entrenchments will lead us only into further disasters, inexorably.

    Of course, RBH, one must take into account a dizzyingly complex array of variables in understanding the impact of this spill. Some compounds in the oil may persist for centuries to come, and wreak havoc with the ecosystem. This is utterly obvious. I suppose you can tell me, now, RBH, exactly what the effect of xylene concentrations of 100 micrograms per liter is going to be on phytoplankton? Is that what I was supposed to tell you in this post, RBH?

    BP has given us an incredibly complex problem to research and understand, not that we wanted it. But that’s what it is going to take if we are going to convince the world that ocean drilling is just not worth the risk.

  • bittergradstudent

    Am I the only one that saw that image, and had to read a bit before I figured out that this wasn’t an article about an Islamic invasion of the eastern seaboard?

  • Jeff

    I think you dropped a factor of 1000 in the ratio of total gulf volume/oil spill volume: the gulf is 3 billion times larger not 3 million. Using your oil spill volume (7.8 x10^5 m^3 = 7.8 x 10^-4 km^3) and gulf volume the EPA general fact sheet you linked to stated (2.4 x 10^6 km^3) the ratio is 2.4 x 10^6 km^3 / 7.4 x 10^-4 km^3 = 3 x 10^9. This also fits the picture you provided to show the volume of the oil spill better. A cube with sides approximately 144 times wider than the black cube shown is not nearly large enough to be the volume of the gulf of mexico.

  • John

    Let’s see. The volume of the spill is 780,000 cubic meters. The volume of the Gulf is quoted as 2,434,000 cubic kilometers at the EPA website. 1 cubic kilometer is 1o^9 cubic meters; I was using 10^6, thanks for catching this! Brain cramp. Big time. Oops. Crap. I will fix the post…300 parts per trillion is a lot better that 300 parts per billion, clearly. But we still do not know the ultimate toxic effects of all the components of the leak.

    I am in fact watching CSPAN coverage of the House hearings on the spill and seafood safety, right now. This is still early days and we don’t know a lot yet. But it is gratifying to see that the EPA, NOAA, and the FDA are firmly rooting their positions in research and real data, much of it still to come.

  • Lab Lemming

    Why the pentagon for scale? Wouldn’t, say, an oil tanker be more useful?

  • Carl Brannen

    “We came damned close to fracturing the sea bed, in which case the entire oil field could have eventually leaked out into the Gulf before we could stop it. I read one estimate that this would have been a total release of oil a thousand times greater than this. We dodged that one, but we need assurance that this can not and will not happen in the future before we continue to drill in deep water, or in shallow water for that matter.”

    On reading this I flashed back to the popular fears (among the clueless public) that the LHC was going to create a black hole that would eat up the earth. If it were only so easy to get oil out of the ground it would have happened naturally a very long time ago.

    To put 0.3 parts per billion in perspective, note that the famously effective nerve agent Sarin (500x more deadly than cyanide) is “minimally toxic” (i.e. survivable) at a dose rate of 0.5 mg per a 100kg adult = 5 parts per billion. And the US gov alone has dumped thousands of tons of nerve agents into the oceans.

  • Eugene

    Tim Lewis’s response is a classic illustration of how frustrating it is for me to discuss science rationally with some people who are emotionally invested in one side of the argument. I am totally for getting angry about BP and the oil spill, but when it comes to understanding the impact of such a disaster, let’s leave the emotions at the door mmkay?

  • Tim Lewis

    Nothing is as indignant like some one defending an idea that is based on a bias that they can’t or don’t want to question. Eugine, John oh my.

    Perhaps people react like I do from your writing is because you, on purpose or accident tried to minimalize something horrific. Using your logic here the Holocaust was trivial, because it took place only over a couple years and compared to all of human history that’s nothing right? And since it already happened what’s the big deal if it happens again right?

  • bittergradstudent


    So, anything that anyone says about the BP oil spill is defenisble, so long as it makes the oil spill look bad? And calling them out on this is ‘apologetics’?

    Because that seems to be your argument here. The OP was a narrowly-focused piece on figuring out where the hell the same rough statement about Manhattan came from. It concluded that it was, in fact, not a manhattan-sized amount of oil. That bit was wrong. There was almost nothing on everything else.

  • Dave

    John, if you want to figure out where terms like “Manhattan-sized plume” of oil come from, you really need to check the press releases that came out along with this Science paper. I believe that Science, along with Nature, releases a press release with every issue. Often, the universities or labs of the authors of the article release news releases as well. For something with such PR potential as this, it might be that other groups have released press releases as well. Any journalist who isn’t on the Science or Nature black list for violating an embargo, can get access to the article and press release several days or a week prior to publication. So, an interested party, like an oil industry or environmental group could get notification in time to release their own press release before the story is out.

  • Tim Lewis

    Bitter, does the resoning you use for this atrocity work with genocide? How about rape or slavery? When a person makes the case that some is ok then you give away the moral imperitive to stop it. When we set the bar at ‘a little nuclear war is ok’ then we ensure we will have another and another. Its ethics, most people think they already ‘have’ it so why learn about it but unfortunately the majority of people don’t know the basic concepts.

    That is why its ok for industry to destroy our ecosystem for profit, because its just a little compared to the whole planet right?

    To discuss how to prevent this again we have to recognize its wrong, not a ‘little wrong’ or ‘comparitivly bad’, its zero tollerance wrong or it will happen again and again.

  • improbable

    “Bitter, does the resoning you use for this atrocity work with genocide? ”

    Yes. It does.

    It matters to have a decent estimate of how many people died in Rwanda, of how common rape is, of how much oil is in the gulf. None of these things are known perfectly, so to obtain such estimates, you need to have a conversation. And some people in the conversation are going to have lower estimates than other people.

    Which of these three sentences is controversial?

  • Tim Lewis

    Of course you have to know it, study it, get all the details but you can’t start with the idea that we will approach with no moral judgmental.

    It’s bad. Pollution is bad, for the planet, society, for everyone. No amount of pollution is ok.

    The idea that we can’t study something with the belief that it’s bad is not a good idea, we shouldn’t check our ethics at the door when we think and talk about stuff. Say a person was to write something about how Jeffrey Dahmer wasn’t so bad because other psychopaths did worse. It’s like saying that being a little bit of a psychopath is ok to some degree.

    We should be outraged and the science and thought shouldn’t rationalize why it wasn’t so bad even with caveats and exceptions. We as a society have to see this as all bad and un-acceptable or they will do it again, next time bigger and take less responsibility for it.

  • improbable

    “No amount of pollution is ok.”

    No this is wrong. Some oil seeps out into the sea in lots of places, naturally, and is eaten by bacteria, etc. This leakage provides some kind of scale on which to measure man-made spills. (Of course it’s not one number, the sea isn’t well-mixed. But you can study it locally, and get some kind of yardstick.)

    Clearly this one is too big, it shouldn’t have happened, etc. And I understand that there are places where expressing anger is completely the right thing, like in a demonstration. And I do understand that this anger can lead to positive changes, making future spills less likely.

    But there must also be places for reasoned discussion of how much, and how bad. It seems like a science blog is such a place. And pointing out that a “manhattan-sized” plume is only 10mm thick seems like a worthwhile point about media hyperbole. (It seems like it’s necessary that authors include a disclaimer paragraph to distance themselves from looneys, which is a small overhead, but one which the author John did pay.)

    Of course sentences from reasoned discussion can always be plucked out of context and used by one side for political gain. But, tough shit, this simply isn’t reason enough not to have the discussion. Truth is much much more important that that.

  • Tim Lewis

    All pollution is bad. If its natural or normal its not pollution. Saying some man made pollution is ok, gives industry the right to do just that much and to push the envelope.

    A drop of oil spilled in order to satisfy some ones greed is not ok. There is no incentive or reason to make it better if that isnt the foundation of the discussion.

    Otherwise your just making excuses about how much can we get away with, what’s the maximum amount we should allow. That leads to your base line getting nudged up little by little. That’s the same reasoning that caused this one.

  • improbable

    Well if you’re going to treat all numbers above zero as the same, then of course you don’t need to measure the size of anything.

    Then we can start prosecuting the nurse who dropped a thermometer just the same as the owner of the factory which spilled whole kilograms of mercury, right? And likewise the guy who dripped some mayonnaise from his sandwich into the sea, right? (Sunflower oil, unlike crude, never naturally gets into the ocean.)

    This is why we try to measure things. And to measure them, we need sometimes to sit and discuss how well we are doing it. This simply isn’t an evil activity.

  • improbable

    Well if you’re going to treat all numbers above zero as the same, then of course you don’t need to measure the size of anything.

    And we can start prosecuting the nurse who dropped a thermometer just the same as the owner of the factory which spilled whole kilograms of mercury, right? And likewise the guy who dripped some mayonnaise from his sandwich into the sea, right? (Sunflower oil, unlike crude, never naturally gets into the ocean.)

    This is why we try to measure things. And to measure them, we need sometimes to sit and discuss how well we are doing it. This simply isn’t an evil activity.

  • Jeremy

    “If we were to take this volume and spread it out in a layer 1 millimeter thick, it would cover an area of 780 million square meters, which is a square about 28 kilometers on a side. The satellite images of the oil slick showed affected regions much larger than that, from which I conclude that the thickness of the surface layer must have been much less than 1 millimeter at those times.”

    Well, oil tends to spread over microscopically (or close to) thin layers on top of water. This is why you get the rainbow-looking effect when you see car oil on top of water–it’s thin film diffraction.

    However, the oil coming from the bottom of the gulf isn’t pure/refined like the car oil you see spread over a puddle in a parking lot. A lot of the plume is actually heavy enough to sink to the ocean floor long before it could reach the surface.

    So what you see in satellite images of the surface is doubly misleading–the total surface area is much larger than extent of most of the plume, since it spreads over a very thin layer, and below the plume, you have a small, thick, very high concentration region.

    The composition of these two regions will differ, too, obviously. The surface is mostly composed of the lighter materials that will evaporate more easily, while the interior region will be formed of heavier material that either sinks to the ground or is taken by the current to shore to form ‘tarballs,’ etc.

    Because most of the oil underground is composed of thick sludgy material, you would expect most of the oil to sink to the ocean floor, and only a few tens of percent to float to the surface or wash up on shore. This is actually what happens to most of the oil that naturally comes up from the ocean floor. The entire ocean floor is actually covered in quite a bit of oil, and it’s been suggested that at some point in the future when oil becomes more scarce it may be cost-effective to start harvesting oil from the sea floor! (Although I do not know the predicted amount offhand, and I think there are fairly large uncertainties attached to it.)

    This is also why you see oil recovery in these kinds of oil spills in the 10-20% range, and not higher. There is really not much more than 10-20% of the oil that is available on the surface for recovery! (Most of what ends up on the shore was actually never on the surface for recovery, it was submerged in the bulk of the plume until the current takes it to the shore.)

    We can compare the oil spill to the natural amount of oil released into the gulf/year, and can see that in the ~80 days the oil spill was going on, it leaked ~1/10 the amount of oil that naturally ends up in the gulf. Because the 10x larger natural leakage number is not happening all in one place, its effects aren’t as obvious since large amounts of oil doesn’t wash up in single places (although many coastal cities in Mexico apparently regularly get lots of tarballs and oil washing up due to them). (This also means it has a large uncertainty attached to really you should think ~1/10 means “order of magnitude”.)

    So, to approximate the environmental effects of the spill, you can concentrate on areas where large amounts of oil have washed up on shore where the current has taken the plume, and underwater areas where the concentration is very high. So, basically, the plume and where the plume intersects the coast are the areas where environmental effects are expected to be noticed.

    The concentration in the plume of this spill isn’t really any different than in any other large spill, so the environmental consequences aren’t really expected to be more significant than other similar spills. So one expects to see noticeable, but by no means catastrophic effects.

  • bittergradstudent



    But perhaps it is somewhat sensible to talk about estimating how much pollution and how bad it is. I have a feeling that the consequences of this lie somewhere between ‘irrelevant non-issue’ and ‘planet-destroying disaster on the level of exploding the entire US and Soviet nuclear arsenal’.

    figuring out where it lies on that continuum is important for holding BP/Deepwater accountable, figuring out how to respond and clean up, figuring out how to take future precautions, and many other things. And we belittle everything if we just always take the high end, most hyperbolic estimate of everything. And yes, similar logic does apply to genocide and rape. Any public policy response must depend on how much problem there is to solve. This doesn’t make any individual instance less important/disenheartening, and doesn’t mean that you shouldn’t repsond to EVERY individual instance.

    What it does mean, though, is that solutions to problems depend on the scale of problems.

  • Mandeep

    John- i’m glad you’re digging into the details, and good to see the discussion — this does matter, a lot.

    One more correction though, that i saw on volume, and your #12 above doesn’t i think still get it right: V_spill =~ 0.8e6 m^2 = 0.8e-3 km^3 right, and V_gulf =~ 2.4e9 km^3 . so V_spill/V_gulf = 0.3e-12 = 300e-15 = 300 parts per *quadrillion*, no?

    I first picked this up when you said in the body that the Gulf has a total volume of 3e9 times the spill and that just seemed way too small.

    Just briefly — as you, and others, point out — this is *NOT* to minimize at all what this spill (really more accurately, horrible catastrophic result of a months-long undersea gusher) means — i personally have written a lot saying this *should* be our wakeup call before something *even* worse happens as far as our fossil fuel addiction goes, not to mention climate change disasters waiting to unfold (Pakistan, anyone?), but we of course need to get our numbers exactly right when presenting them from the getgo.

    Thankfully, the Obama Admin is making *some* changes to our energy policy, supporting more wind and solar, etc. — but much, much more, and rapidly, needs to be done.


  • Hmmm

    While we should certainly have a rational discussion, the original post did give me the impression that the oil spill wasn’t as bad I thought. And I sorta bought it, because you guys are physicists over here [1]. It is only in one of your (John’s) responses to Tim Lewis that I learnt that we came damn close to breaking the sea-bed … which would have been a disaster – to put it mildly.

    Wouldn’t the last argument alone be enough to seriously re-consider deep-sea drilling? Intellectual debate over fine points have a tendency to stagnate in inaction, while the big evil corporations get what they want. It is a trade-off, is what I am saying….

    [1] Lets forget for a minute that so am I.

  • Yeah

    Tim Lewis is one of those funny personalities you meet on the internet who have the property that while I don’t really disagree with anything of substance that he says, I find the kind of ranting he engages in to be at best counter-productive.

    I suggest that his computer or laptop and whatever powers it (even if it is solar, the batteries) have been responsible for a non-zero amount of pollution during its manufacturing and operation. The only sensible thing to do at this point is to stop contributing by taking it apart and carefully recycling each component.

    Hmmm has a good point, John — I would suggest you consider adding the point about breaking open the sea bed to the main text. That’s the beauty of blogging, you can adjust in real time.

  • John

    Tim, re #16: When did “understand accurately and fully” become “minimalize” [sic]?

    Jeremy, re #26: Excellent points. BP is claiming to have recovered from the surface of the Gulf a huge amount of “oil mixed with water” but I would be wiling to bet it’s 99.99% water. Not that they should not do this!

    Mandeep, re #28: Again, the volume of the spill is 780,000 cubic meters. The volume of the Gulf is quoted as 2,434,000 cubic kilometers at the EPA website. 1 cubic kilometer is 1o^9 cubic meters. So the ratio is 1:3,120,512,821, or one in three billion. Or 320 parts per trillion. I hope I have it right this time!

    Lastly, Carl (#14) my point about fracturing the sea floor was that the immense torque of the falling platform on the riser pipe at the sea floor could have caused the sea bed nearby to fracture, and oil to leak out of a much less well definable place than the 20″ riser pipe. It could have been next to impossible to stop. Hmmm (#29), this was discussed at length in the days leading up to the final cap put on the riser pipe: the idea that if there were such fractures, and the riser pipe was damaged below the sea bed, capping the gusher could have caused failure of the surrounding sea floor. Thad Allen made sure that systems were in place to monitor for seepage indicative of imminent failure (in which case I assume they would blow the cap open?), and the crews worked very deliberately at the end to avoid triggering any such event.

    Compared with the probability that the LHC could produce an Earth-destroying black hole, I think the sea-floor-rupture scenario is about, oh, 10^30 times more likely. Which is to say, the probability of a sea-floor-rupture event creating essentially an undersea oil volcano is not at all negligible (whereas the LHC black hole thing is negligible). This must be considered in any future deep water drilling.

    But your main point, Hmm, that the original pre-comment tone of the post was that things were not as bas as they seemed, echoes Tim Lewis’ concerns. I have to say I was surprised when I calculated that the total spill volume was “only” a cube of side 92 m. But it did not make me want to suppress that information, as it seems to make some want to do. We need to deal with this disaster with the facts. I bet that when we do we will begin to conclude that we have been reckless in the extreme, in ways that we have not thought of yet.

  • Richard E.

    Tim: “All pollution is bad. If its natural or normal its not pollution. Saying some man made pollution is ok, gives industry the right to do just that much and to push the envelope.”

    Even if we buy this argument, man-made pollution began with fire (if not before), which leaves behind ash and releases smoke and particulate matter — some of which will have been carcinogenic. Almost any human activity has consequences. But I doubt many people would join you in wishing for some paleolithic EPA to put an end to this particular piece of environmental brutality.

    (Also, John, my guess is that the “cracking the sea bed” thing is rubbish – — might be wrong. and I didn’t look into in detail, but a friend sent me a link about that with a “can it be true?” when the leak was going full blast. Said friend was genuinely concerned, and poked around and traced that particular version of it back to some clown whose blog was full of a weird amalgam of Alien visitations, Tea Party ranting, conspiracy theories (the well was blown up by a North Korean minisub) and hard-line fundamentalism of the Christian variety, and at that point I gave up digging :-) But it sounds unlikely on the face of it — oil is not just sitting there waiting to escape like pus in some giant subterranean zit, while the seabed itself is fairly plastic and unlikely to “fracture” in any meaningful way. I think there might have been some worry that the well was leaking from the base, and the oil was escaping into the surrounding rock, but I am not sure it is possible to drain an entire oilfield by drilling a single hole, even if you wanted to.)

    (Edit: I think you were talking about a somewhat less dramatic scenario. Sorry)

  • Carl Brannen

    “immense torque of the falling platform on the riser pipe at the sea floor could have caused the sea bed nearby to fracture, and oil to leak out of a much less well definable place than the 20″ riser pipe.”

    LOL. The total depth to the reservoir (from the gulf surface) is 5000 feet of water and then 13,000 feet of rock. The concept of 2.5 miles of rock “fracturing” due to torque applied through a 21 inch diameter pipe is the kind of thing that is appropriate for a bad made-for-TV movie. Like the example of the LHC black hole, these sorts of fears are due to people making wild extrapolations far beyond their education or area of expertise.

  • Jeremy

    I don’t believe that the rig could “fracture” the *whole* seabed (the material properties of the pipe are not nearly strong enough!), but it could cause small local fractures at the top of the seabed, connecting to the drilling shaft. Like you mentioned, the engineers were worried about cracks near the top of the sea floor in the area of the pipe, which was why measuring the pressure once they capped it was so important.

    So, if there are cracks, even if you capped the leak oil would still leech out of the ground. But that wouldn’t be as bad as you might think.

    A good analogy for why, when I moved into my apartment the pipes under my sink were leaking because it had been recently taken apart to fix. After a few months, sediment (well, and probably rust from the crappy pipes in the old building…) had filled in the threads in between the pipes that the water had been escaping though.

    Basically the same thing would happen to cracks in the seabed, as long as they were not horribly severe, they would eventually fill with viscus oil and the leak would stop.

    If the cracks were more significant, then dumping debris like rocks, gravel, dirt, etc, would slow the flow enough for it to be stopped (and it can’t be *too* severe, I think the pressure being too high would cause cracks to collapse, plus, you would have noticed large cracks before hand anyway). This is what they tried to do with the well, too, but the pressure was too high and just blew anything they tried to dump on it away. But the pressure through any fractures would be much less.

    Also, your exponent in the relative probability of world-destroying black holes is missing quite a few zeroes…

  • Mandeep

    John- ah, woops, my mistake — i wrote V_gulf = 2.4e9 km^3, but it’s 2.4e6 km^3 (i just read it wrong, think i’d done the calculation earlier and mis-remembered some part of it).

    And this makes sense given the dimensions that they give on the site, roughly (order of magnitude) 1k km on a side, and probably an avg of 2km deep, or so, ~ 2e6 km^3. Ok, sorry again, but that’s the self-correcting ‘magic’ of science — we do hone in on the right answer eventually, and, egos aside, we’re all happy when we ultimately agree on things. ;->


  • John

    Richard E. and Carl Brannen, what JEremy wrote is what I meant, though how quickly the oil flows out depends on the details of the break, clearly. If the riser pipe had cracked below the seabed, and the nearby rock had fractured, such that oil was coming from not just the main drill hole but also from fissures extending radially from it at the sea bed, how would you stop it? I agree with Jeremy’s analysis, but it all depends on the exact nature of the break.

    Yes, this is a low probability scenario. But what is an acceptable level of risk given the consequence of such an event?

  • SteveB

    Thanks for the article John. I had imagined a much larger volume. I had to Google for the volume of a barrel because I thought you had gotten it wrong — but no.

    Tim Lewis is on my “never to be read again” list. What a weirdo!

    People are wondering about the affects of the surfactants released into the plume which some hypothesize were being used to decrease the visible effect of the spill, even though biologists were very upset because it may have made things worse biologically.

    Natural oil seeps happen. Nature has evolved to handle them (in smaller doses I would guess). Look for Coal Oil Point information (near Santa Barbara, CA). An article on that indicates a natural gas seepage of 1.o – 4.o x E04 M^3 per day in that area.

    Natural seeps don’t get surfactants mixed in….

    Yes, if the capping went badly a large, uncappable, unnatural seep in the environs of the riser pipe could have happened. I am very glad they took their time, and I am very glad it appears to be holding.


  • spyder

    60 minutes last night had a forty minute interview with a key engineer who was working on the site for Transocean (also four fishermen who happened to be fishing under the rig and rescued the engineer, and a professor of engineering and drilling). If nothing else about this issue is fully and perfectly clear, the abject failure of the parties, concerned with the drilling and the well, to work safely and correctly were at fault. At each step, huge catastrophic failures resulted in a cascade of problems that literally exploded every aspect of the operation. The fire proof safety doors (300# and 3″ thick) were blown off their hinges for gawd’s sakes. After months of drills the crews panicked rather than follow procedures. And that is the small stuff.

    The problem is not the amount of oil per se, but the reckless disregard for the potential of an incident at any scale. Keep in mind that there are four more rigs out there operating much like this one.

  • Gary

    “All pollution is bad.”

    Since when is a naturally occurring substance “pollution”?

    When it offends someone’s personal sensibilities?

    The Earth vents all sorts of liquid and gaseous “pollutants” into the ocean, air and across the land all the time. Always has.

    Ref: mass extinctions; for real effect.

    If Gaia didn’t want hominids to occasionally facilitate the process it should hope for an asteroid or comet to get rid of us meddling busy-bodies.

    Nothing more natural than a dumb rock saving the environment from us carboniferous carbon polluters.


  • Ijon Tichy

    Thanks, John, for an enlightening article. I really wish the political types would simply f*** off when rational people discuss energy and pollution issues. For his next article, John should compare how deadly is the average TWh of energy generated from nuclear fission to the same amount generated by natural gas.

  • Anonymous_Snowboarder

    And what is the volume of the Pentagon? “The size of the Pentagon is 77 ft (height) and 921 ft in lengthPentagon Dimensions (281 m). It covers an area of 35,580 sq m (383,000 sq ft).” Thats a height of 23.46m so a volume of about 835,000 m^3. So yes, the oil spill is order of one cubic Pentagon, a new unit of measure for liquid disasters.

  • Brian137

    Here is an article from titled

    “Study shows deepwater oil plume in Gulf degraded by microbes”

    From the article: “In the aftermath of the explosion of BP’s Deepwater Horizon drilling rig in the Gulf of Mexico, a dispersed oil plume was formed at a depth between 3,600 and 4,000 feet and extending some 10 miles out from the wellhead. An intensive study by scientists with the Lawrence Berkeley National Laboratory (Berkeley Lab) found that microbial activity, spearheaded by a new and unclassified species, degrades oil much faster than anticipated. This degradation appears to take place without a significant level of oxygen depletion.

  • Gary

    Ijon Tichy said:

    “I really wish the political types would simply f*** off when rational people discuss energy and pollution issues.”

    “political” is your irrational assertion insofar as you’re awfully picky about which “political types” pervading this place can not freely opine without your personal intervention.

    “wish”-ing is not rational behavior.

    “simply f*** off” is not a rational reaction to 1st Amendment protected free speech.

    “rational people” is not a term you seem overly familiar with in actual practice.

    Life, itself, is more deadly than nuclear fission or fusion. 100% deadly.

    Kill all stars; save life!

  • Anonymous_Snowboarder

    Just a follow up from an AP story that hit his morning which says a new microbe has been chowing down on the oil plume and it is not significantly affecting the oxygen levels. Story is here.

  • John

    Do the microbes eat benzene? Xylenes? All the crap in the dispersant Corexit?

  • spyder
  • John

    What on earth is the administration and BP thinking? That they will just get away with this?

  • Brian137

  • Anonymous_Snowboarder

    File a FOIA request for the data. But I hardly understand the shock and outrage that the government would try to hide things from the people. Has Obama done even one thing in regards civil liberties or open government? If anything, some of what he has done or proposed to do are extensions and additions to Bush era policy.

  • Jobe Roberts

    Discover Magazine is now off my reading list since it publishes garbage like this.

    “John”, Why don’t you go down to the Gulf and have a look to see if the oil spill looks at all to be the size of your square pentagon cube? Of course, we all need to be calm, rational, and scientific about this disaster since it will just evaporate and get eaten up by magical oil loving bacteria before we know it. Nothing to worry about, keep up the drilling, we need the oil more than we need silly stuff like fish and birds.

  • Pingback: just another chemistry weblog » Friday Science Spree 08/27/10()

  • Pref

    The oil spill was a mess,,, but everyone seems to say it’s a man made mess. Yes we drilled the hole that allowed an exorbant amount of oil to come to the surface. But isn’t oil all natural? Isn’t it the byproduct of years of evolution? Isn’t it the breakdown of plant and animal life of all sorts? This is not a man made compound… Or were we taught wrong on this?

  • John

    Sorry to lose you, Jobe Roberts…I hope I made it clear in the original post that I am no fan of sea floor drilling, deep water or otherwise. The risks are just too great.

    But, as I also pointed out, people bring their own prejudices and biases to the reading and interpretation of any text, and when their preconceived notions are threatened, they react negatively. The comments above are a vivid demonstration of that.

    Pref: there are a lot of completely natural things that are not very good for life. Supervolcanoes, asteroid impacts, ice ages, droughts, and yes, mankind’s various activities. We are living through a great extinction of living species that is of our own making, and not just due to oil drilling.

  • greg

    Regarding the comment that a thimble is small compared to a person but who would drink a thimble of oil.

    I would. However, the apt comparison is more akin to a molecule of oil and ten or twenty human bodies……you get a lot more PAH than that every time you eat bar-b-q or smoked fish. – am a marine scientist who has piblished on oil spills and seafood safety.

  • Jobe Roberts

    Mr. Conway,
    My negative reaction is due to your make believe oil cube. This does not convey to anyone the real magnitude of the disaster, it marginilizes it.
    It’s pretty hard to tell from this blog post that you’re not of a fan of deep sea drilling. How is it that your rational examination of the disaster doesn’t include any real-life impacts? Attempting to calculate the oil to water ratio is, to use your own words, BS.
    Perhaps if your picture visualized the real-life death toll, your message might not be so misunderstood by us prejudice readers.

  • John

    Jobe Roberts, my post was written after hearing “Manhattan sized plume” and then going and actually calculating the volume of oil released. The answer surprised me, and I bet it surprised just about anyone. We all have this image of miles and miles of oil, and “plume” makes it sound like all the oil is in one place, that it’s somehow contained.

    The earlier claims that the oil was “gone” or “evaporated” or “eaten” were rubbish, and the Science article made that clear. But people are still left wondering how to visualize where the oil is now, how concentrated it is, what are its components, how toxic are they, and what the eventual impact on the environment and them is.

    If we really want to stop sea floor drilling, or at the very least make companies do it in a manner orders of magnitude safer than they do today, we have got to make a rational, scientific case. This is not a political matter – duking it out in the political sphere will lead nowhere because there is too much money to be made. We need cold hard facts based on good science to make sure this tragedy cannot and will not happen again.

    I can see how you might read into what I wrote that I was minimizing the spill. But what I was trying to do is make you, and all the other readers, really think about the true facts of this disaster, and not simply resort to knee-jerk reactions.

    Read again the last sentence of the post. BP is doing everything it can to sequester information, not release it publicly. This must stop.

  • Brian137


    I like John’s OP. I appreciateded his clarification of the currently operative definition of the term “plume” and the comparisons to the cube, the one-mm-thick slab, and the very thin film. I do not feel that I misunderstand any more than I misunderstood before reading John’s article. I hope we haven’t caused him to blanch.

  • Jobe Roberts

    It certainly is difficult to comprehend the magnitude of this spill. Sorry for frothing at the mouth. I feel that the planet is in serious peril if we allow this to continue. It is imperative that we do not dismiss this as business as usual.
    I really do think you should consider visualizing the number of dead fish, birds and animals that this attack on nature really is. It might help those of us not so good in math understand what’s going on. Sure, it might be by accident, but it’s no more real and catastrophic to the real animals that perish and suffer for this insane race to suck every last drop of oil out of the ground and for what? So that we can fertilize monocultures and drive around in cars? Yeah, the world needs to wake up to what’s really going on. I think you can do better with your visuals.
    I’d be happy to help with the graphics for your next post. There must be a better way to convey the reality of the situation.

  • Brian137

    Hi Jobe,
    I appreciate your concern. Love and caring are wonderful feelings. You along with all the rest of us are fortunate that you feel them and that you express them. Something happens sometimes whereupon these kind feelings transmogrify into cynicism when others do not respond according to our adopted standards. My advice, which, of course, you did not request, is to do your best, but to also stay happy within yourself and well-disposed towards your fellow human beings, a diverse and occasionally rambunctious lot. My apologies if I either presume or intrude. Good luck to you.


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