Use of Dispersants in the Gulf Proves to Have Little Benefit

George Washington's picture


Dr. David Valentine - one of the world's leading experts on oil-eating bacteria - told me today:

We have found no Alcanivorax borkumensis in the deepwater plumes.

That may not seem like a very interesting or controversial sentence.

But it is actually a jaw-dropping statement, showing that the use of Corexit in the Gulf has failed by any measure.

To understand why, let's quickly run through the science of the oil spill.

Why Was Corexit Used in the Gulf?

many - including me - have accused BP of dumping millions of barrels of
Corexit in the Gulf in order to hide the oil, some scientists argued
that Corexit would make it easier for oil-eating microbes to break down
the oil.

As Scientific American pointed out in May:

last (and only) defense against the ongoing Deepwater Horizon oil
spill in the Gulf of Mexico is tiny—billions of hydrocarbon-chewing
microbes, such as Alcanivorax borkumensis.
In fact, the primary motive for using ... chemical dispersants on
the oil slick both above and below the surface of the sea is to break
the oil into smaller droplets that bacteria can more easily consume.

In fact, there is no clear science showing that dispersants help microbes break down oil. As Chemical and Engineering News noted in June:

those teams’ assumption lie murky data. The authors of the 2005
[National Research Council] dispersant report described the results of
three decades of research into dispersants’ effects on biodegradation
as “mixed” with studies showing evidence for “enhancement, inhibition,
and no effect.”

Nevertheless, tremendous quantities of Corexit have been sprayed some 5,000 feet underwater at the wellhead.

Does Corexit Interfere with the Microbes?

Valentine - a biogeochemist at the University of California, Santa
Barbara - received funding from the National Science Foundation to
characterize the microbial response to the Gulf oil spill. The National
Science Foundation has funded Dr. Valentine's research into how the
oil-eating microbes are dealing with the spill, and whether or not
Corexit is interfering with the microbes' ability to break down the oil.

As I wrote last month:

might be killing the oil-eating bacteria which would otherwise break
down the oil. University of Georgia scientist Samantha Joye notes that
scientists have no idea how the large quanties of dispersant will effect the Gulf's microbial communities (for more information, watch part 1, part 2, part 3, part 4 and part 5 of Dr. Joye's July 13th press conference).


Moreover, as MSNBC notes, oil-eating bacteria are less active in deepwater, where much of the oil sinks after treatment with dispersants:

note that little is known about the deepwater ecosystem — or how the
oil and dispersants will react under extremely high water pressure, very
low temperatures, limited oxygen and virtually no light.




conditions at the bottom of the Gulf also could affect the bacteria
that help break down the oil near the surface, as they are less active
in cold temperatures than in the warm surface waters, and they may be
less abundant in the deep.


“We know that the surface material
has been degrading,” says Ralph J. Portier, professor of environmental
studies at LSU. “But what about the microbial population at depth?”


As Scientific American points out:

colder, deeper waters inhibit microbial growth. "Metabolism slows by
about a factor of two or three for every 10 degree[s] Celsius you drop
in temperature," notes biogeochemist David Valentine of the University
of California, Santa Barbara, who just received funding from the
National Science Foundation to characterize the microbial response to
the ongoing oil spill. "The deeper stuff, that's going to happen very
slowly because the temperature is so low."


At the same
time, the addition of ... dispersants deep beneath the surface is having
uncertain effects; it may even end up killing the microbes it is meant
to help thanks to the fact that Corexit 9527A contains the solvent
2-butoxyethanol, which is a known human carcinogen and toxic to animals
and other life.

Mother Jones provides additional details:


Valentine ... warns the stuff may be riskier than just its toxicity.
Corexit may undermine the microbes that naturally eat oil.


Some of the most potent oil-eaters—Alcanivorax borkumensis —are relatively rare organisms that have evolved to eat hydrocarbons from naturally occurring oil seeps. Valentine tells Eli Kintisch at Science Insider that after spills, Alcanivorax
tend to be the dominant microbes found near the oil and that they
secrete their own surfactant molecules to break up the oil before
consuming the hydrocarbons. Other microbes don't make surfactants but
devour oil already broken into small enough globs—including those broken
down by Alcanivorax.


What we don't know is how the
surfactants in Corexit and its ilk might affect the ability of
Alcanivorax and other surfactant-makers to eat oil. Could Corexit
exclude Alcanivorax from binding to the oil? Could it affect the way
microbes makes their own surfactants? Could Corexit render natural
surfactants less effective?


The National Science Foundation has awarded Valentine a grant to study the problem.

borkumensis is the main microbe breaking down oil in the Gulf. For
the real science nerds, here are two illustrations of how breaks down
oil (click either image for full graphic):

No Microbes in Deepwater Plumes

I spoke with Dr. Valentine today, I asked him whether he has reached
any conclusion as to whether Corexit interferes with the ability of
Alcanivorax borkumensis to break down the crude.

He replied that he doesn't yet have any findings on that issue.

However, he said, "We have found no Alcanivorax borkumensis in the deepwater plumes".

asked him whether that was because of the cold temperatures deep under
the surface of the ocean, and he replied "we don't know".

I had been worried that the microbes would break down the crude in the underwater oil plumes more slowly than normal ... but Valentine said there are no microbes at all down in the plumes.

Mongeese, Rats and Deepwater Oil Spills

The mongoose was introduced to Hawaii in order to control rats (the rats were eating the sugar cane used to make rum, and so were a real nuisance).

It didn't work out very well - mongeese are daylight-loving creatures while rats are nocturnal . So the mongeese didn't control the rats, and instead ran amok and trashed many native Hawaiian species.

scientists who assumed that Corexit would help the microbes break down
the oil from the Gulf spill haven't fared much better.

Remember, the US Minerals Management Service and a consortium of oil companies - including BP - found that as little as 2% of the oil which spills from deepwater wells ever makes it to the surface of the ocean. As Alexander Higgins noted in June:

[A] study called Project “Deep Spill”
... analyzed a wide range of controlled releases at different depths
below the sea surface of different types of oil found all over world
to help better understand the flow of hydrocarbons released from a
deepwater blowout.


One of the studies, called DeepBlow, released
10,000 barrels of oil per day at a depth of 800 meters which is less
than half of the depth of the Deepwater Horizon blowout.


The basic findings of that study has been recreated by scientists from the University of North Carolina.


In their research the scientists simulated of the formation of the underwater oil plumes that are created during deepwater blowouts.


Watch The University of North Caroline Simulation Shows How Oil Released Underwater Forms Plumes

the University of North Carolina simulation gives you a basic
understanding of how deepwater blowouts create oil plumes it does not
fully account for all the findings of Project “Deep Spill”.


In particular the final report of Project “Deep Spill” found:


1. Only 2% of the oil released in a deepwater blowout may actually make it to the surface.
That’s as little as 2% naturally without the use of dispersants. Add
dispersants into the equation and it could be less then one percent of
oil that makes it to the surface.




The buoyant parts of the oil released in a deepwater blowout split
from the main plume within the first 200 meters of release. Those
buoyant parts, which represent only a small portion of the total amount
of oil, turn into small droplets that float to the surface.

Here is a graph from the study showing this process.

Deepwater oil release - Buoyancy particle separation graph
Deepwater oil release – Buoyancy particle separation graph

Here is an image that captures the separation process

Deepwater oil release - Buoyancy particle separation simulation
Deepwater oil release – Buoyancy particle separation simulation

Deepwater oil plumes lose buoyancy within the first few couple hundred meters from release

Within the first 100 to 200 meters from the source of the release the
the majority of the oil loses its buoyancy and stops rising. This
majority of the oil remains submerged in an underwater plume that is
then carried away by subsurface currents.

As the University of California Santa Barbara notes, microbes like the lighter portions of the oil:

The microbes prefer the lighter compounds of oil, the gasoline part of the black goo ....

always seems to be a residue," Valentine said. "They (bacteria) hit a
wall. There seems to be stages in which they eat. There's the easy
stuff ––the steak. And then they work their way to the vegetables, and
then garnish, and then they stop eating after awhile. Just depends on
how hungry they are and what's fed to them."

Corexit: A Failed Science Experiment

So let's recap.

The overwhelming majority of oil from deepwater spills stays beneath the surface in plumes. See this and this.

Corexit helps oil to sink beneath the surface, so even more of the oil stays underwater. Oil-eating microbes like the lighter portions of oil.

Dr. Valentine found none of
the main oil-eating microbes in the deepwater plumes he tested. Whether
that is because the Corexit killed them, its too cold in the deep
ocean, they don't like the heavier portions of the oil that don't float
to the surface, or for some other reason, the result is a failure.

Scientists have already said that Corexit is dangerous to sealife and humans (see this and this),
and called the application of Corexit the largest science experiment
ever conducted. For example, Rob Kendall, director of Texas Tech’s
Institute of Environmental & Human Health, says:

is a catastrophe of enormous proportions. To me, this is the biggest
environmental toxicology experiment we’ve ever conducted.

And Kim Withers, a coastal ecologist at Texas A&M University in Corpus Christi notes:

It's like the biggest science experiment ever. Unfortunately, it's a completely uncontrolled experiment.

They were talking about the toxic effects of Corexit on sealife.

Dr. Valentine's findings lead me to conclude that the experiment on the
potential of Corexit to help the microbes break down the oil has failed
as well.

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anonnn's picture

Presidential haiku:


Corexit CDs hedge funds,

anti-social clever-strokes, 

Tell the truth and run.

blindman's picture



1 week ago 37

To my friend Gustavo, who was drummer and a big fan of Floyd, hewas killed this saturday with a? shoot in the head during a robbery. WE WONT FORGET YOU!


speaking of dispersants...and delta toxicity. 

RichardP's picture

My condolences blindman.

RichardP's picture

Just a small pet peeve.  In all of the postings that G.W. has done on the Corexit issue, many posters have expressed supposed genuine concern about the sea life suffocated because of the oxygen defict created by Corexit.  Yet other posters have pointed out that portions of the Gulf have had oxygen deficits for years (with attendant sea kill) because of the chemicals that are allowed to run off into the Mississippi River and into the gulf.  I don't claim to have read every post but I've read most of them.  And no one seems interested in the loss of sea life due to the Mississippi chemical run-off.  Only the loss due to Corexit.  So - it would seem that the loss of sea life is not the real concern here.  Something more political seems to be the concern.  If one was truely concerned about the loss of sea life, I would think they would be concerned about the loss, regardless of cause.

George Washington's picture

Will the dead zones increase in size due to the oil/Corexit/methane?  Is there a  concerted effort to suppress information on the loss of sea life due to the Mississippi chemical run-off?



RichardP's picture

Is there a  concerted effort to suppress information on the loss of sea life due to the Mississippi chemical run-off?

I'm guessing the answer to that one is yes.

Will the dead zones increase in size due to the oil/Corexit/methane?

Over time, I'm guessing that the Mississippi River runoff dead zones will kill more sea life than the BP Well dead zones - because they are persistant.  Although large, the BP fallout is temporary.

G.W., my comments in the post directly above were not directed to you.  It was a general comment on the lack of comment by other posters when the Mississippi River runoff dead zone issue was raised.

Cistercian's picture

 Yes a huge dead zone appears every year in the gulf due primarily to ag runoff.


 Nice distraction attempt...dolt.

onlooker's picture

Anybody here young enough to remember Agent Orange? The good news for the possible health problems from the Gulf oil and chemicals is that we got a new health plan with limited help. The Gulf problem is not, nor will be a health issue. Kinda like Agent Orange--- some of these poor bastards are still alive and still sick. Not our problem, it does not exist. For those who state the Gulf is all better and sloved and was not a problem, we have George Washington to keep some flow of information. LBJ, how much Agent Orange today.  Barry-O how much ocean have you killed today.

viator's picture

Many seem heartbroken that the well is plugged, that the leak has stopped so now we have fractured sea floors and underwater plumes. More Ehrlichite nonsense, part and parcel with peak oil and global warming. Carbonphobia, a dread disease, which seems to have infected a significant minority of our population intent on ending human life as we know it.

RichardP's picture

Many seem heartbroken ... so now we have fractured sea floors and underwater plumes.

Remember that this/these plume(s) are not newly discovered.  They were being discussed in May and June and maybe earlier.  All of the information currently available on them was collected before the end of June (so say all published reports).  What we are getting now are the results of the tests done on samples collected before the beginning of July.  No one even knows if these plumes are still there today, or what their location might be if they still exist.

bugs_'s picture

specific gravity

newstreet's picture

George, I tried to tell you, nobody cares now, rest easy.  Watch some TV tonight, think about some old girlfriend, everything is going to be o.k.




George Washington's picture

Thanks, Anglo-American.  I try to write about nice, happy things.  But then I keep finding new, outrageous facts.

I'll keep trying to think about unicorns and skittles, though ...


Cognitive Dissonance's picture

GW's wife would not be happy knowing that GW is thinking about old girl friends. Thus GW's wife will make GW's life living hell until GW disperses old girl friends from his hair using liberal doses of Corexit.

Mission Accomplished. Wife happy, hair and GW gone, assfire even happier.


Cognitive Dissonance's picture

Those    were    the    days    my    friend.

Oh sorry, just daydreaming. Or tripping......again. I can rarely tell the difference anymore and quite frankly I don't give a damn.

I will tell you one thing though. Those flash back trips are the best value for your money you'll ever get. A few bucks well spent in the 70's and 80's and I'm still getting solid returns on my investment. :>)

blindman's picture

mescalito (peyote)

lasts forever and is all NATURAL




once is enough

snakehead's picture

All I'm doing is posting a link to an article in New Scientist.  Various different perspectives.

snakehead's picture

Yeah, I've seen those.  Actually a careful reading of the initial fed report indicated about 50% left, but they pitched it with 100% spin with the help of the know-nothings in the MSM. I'd bet we're in agreement about that.

GW, you seem to have taken a staunch position. I'm just looking for info from reasonable sources. There's obviously some variability among qualified opinions.

So, from the New Scientist article, here you go:

Contrary to other reports, Camilli also found evidence that oil-munching bacteria were only slowly working through the suspended oil. Together, his and Hallberg's studies suggest that oil will probably remain deep in the water column for at least another month.

But Terry Hazen, a microbial ecologist at Lawrence Berkeley National Laboratory in California, says that he has studied the same plume as the Woods Hole group. His results, which have yet to be published, show that microbes are rapidly eating up the plumes – so much so, he says, that the oil should already have vanished. Hazen is adamant: "The plume is no longer there. It's gone."

Why are the results so different?

For starters, different groups are measuring different things, all of them toxic. Oil is an assortment of hydrocarbons, and microbes consume each component differently. The Woods Hole group is looking at the degradation of monochromatic hydrocarbons known as BTEX, which stands for benzene, toluene, ethylbenzene and xylenes. Hazen, on the other hand, is studying long-chain hydrocarbons such as alkanes.

But the discrepancy still puzzles Steven Lohrenz, an oceanographer at the University of Southern Mississippi, Stennis Space Center campus. He is surprised by the Woods Hole group's findings. "I wouldn't expect [the BTEX] to persist for a very long time in seawater," he says.

The difference in the rates at which the researchers believe microbes are breaking down the oil is another point of difference. Of the three, Hazen is the only one to have measured what microbes in the Gulf are actually doing. What's more, other microbial biologists, including Gary King of Louisiana State University in Baton Rouge and Jay Grimes of the University of Southern Mississippi in Ocean Springs agree with his numbers.


But on the other hand, Science News reports

“In our lab experiments, things mainly get trapped based on their density,” Camassa observes. “So I would expect to find a somewhat sharp transition in density down there, and with such stratification the oil could persist for a long, long time.”

Oil in the plume hasn’t ascended to the surface, he explains, because if droplets are small enough they become neutrally buoyant and move with the water. Camassa’s lab studies suggest that the high-velocity spray of oil from the BP blowout would essentially have atomized the crude oil into microdroplets.

New modeling analyses of the BP oil spill by researchers at NOAA’s Geophysical Fluid Dynamics Laboratory at Princeton University also largely predict what the WHOI team has just reported, notes Robert Hallberg of NOAA.


Note: I'm a lot more concerned about BTEX than the other stuff.  Really bad shit. I hope that shit is *gone*.

Attention, junkers: Best if you burn and bury anyone whose opinion doesn't fit your personal catechism. Me, I don't actually have an opinion yet because people who know a lot more than I do about this stuff are not in agreement. Nevertheless, make this post disappear, even though these aren't *my* opinions. Blasphemy! Infidels! Unbelievers! Stone them!

GW, one more observation. Take a look at the photos from Dalian. There are lots of unknowns about the uncontrolled GoM "experiment" and over time a consensus may be reached that all the Corexit was net bad.  But the shoreline doesn't look like Dalian's.

Mr Lennon Hendrix's picture

"Tell the children the truth!" -Bob Marley

Babylon System- Bob Marley:

tony bonn's picture

george washington for president!

capital punishment for bp!!

AssFire's picture

There is great value in keeping the oil deep- where the current will dilute and disperse the oil. Excellent job- even the Corexit gets diluted! Fantastic News, it is ALL upside, no downside I can "see".

"This is a catastrophe of enormous proportions. To me, this is the biggest environmental toxicology experiment we’ve ever conducted."

GW, I graduated from this cowboy college in the cotton fields of Lubbock far far away from the coast. You manage to find an unqualified quote here or there and magnify it again and again.

So, lets recap- dangerous concentrated amounts of oil and corexit are being swept out to the open sea by deep currents (not in the upper marine life concentrated life) until it is dispersed into low concentrations- it then rises and is eaten by the bacteria- awesome.


But what about those guys who claimed to be spraying Corexit on the SURFACE??

Oh, we maybe they were spraying something else because the corexit isn't used on the surface?? Or just have it both ways- like writing for women- just take away reason and logic.

blindman's picture

the line went .. corexit is used on the surface

to protect surface sanctuaries, nesting areas

and the like.  it causes the surface petroleum

compounds to sink,  like boaters may use detergents

to mask, cause to sink, oil they spill around their

boats if they have a spill or leak that they don't

want to be observed by the authorities / coast guard

or other water police types.  it has been going on for

decades, yo!  some people prefer the terms "disappear"

and   "gone away" but..... you know the truth.  you went

to college!  the world just got a little "dirtier"  with

associated unforeseen consequences.  so it goes when

we cannot refrain from shitting where we eat.

schoolsout's picture

Shrimp come fresh from the mother f'n sea!


local video from my area.   Just thought it was somewhat fitting

schoolsout's picture

As a person that regularly fishes 60+ miles offshore of the SE region (SC, specifically), I know what upwellings are and how currents rise from the deep.

I don't know the geography of the GoM that well, but I'd assume it has some similar characteristics if there is a current located there.  (this is taking into account none of the toxic BS has reached the Gulf Stream).

You see, underwater anomalies such as sea mounts or other rapid rises in the ocean floor can create upwellings.  An upwelling is where water from below hits the change in bottom contour and water/nutrients/whatever else is pushed upwards towards the surface.  As a fisherman we look for areas like this as  marine life of all sorts will congregate in that area. 

Just for your reference, google the Charleston Bump...

It actually pushes the Gulfstream offshore and creates huge upwellings as well as gyres of churning warm water/nutrients/plankton/other micro-organisms that, in turn, lure larger gamefish to the area. 

Again, I have no clue as to how the GoM compares to the East Coast and the Gulf Stream, but your statement is beyond rediculous.

AssFire's picture

Yes, I fish the Sabine bank.   wtf does that do to tear down my logical argument??..This is a deep canyon.

What statement is "beyond ridiculous"

10 second google image search: gulf stream current map

man you guys are cripples.


schoolsout's picture

It may be in a deep canyon, but because it is, doesn't mean it is the only place it is located.  WTF is your point again?


My point is water moves and the contour of the bottom doesn't keep the same water on the bottom forever.  Corexit has allowed the oil to be broken up and scattered throughout the water column.


Who is the cripple?

still kicking's picture

How are you so sure of your statements?  Given you graduated from cowboy college why would you be qualified to remark on this in such a definitive manner?  I'm not GW is correct but I wouldn't say he is wrong either, so far BP has only lied so I know they are wrong, which leads me to think GW just might be correct. 

AssFire's picture

 I am sure because it is the plan. Confusing that no one understands the plan.

newstreet's picture

George, Anglo-American is not liking your posts.

RichardP's picture

We have found no Alcanivorax borkumensis in the deepwater plumes.

That ... is actually a jaw-dropping statement ...

G.W., do you have any information that would state where in the water column the Alcanivorax borkumensis normally live and operate?  That is, are they normally found from the surface all the way down to 5,000?  Without this information, saying that there are no Alcanivorax borkumensis in the oil plumes is not informative, much less jaw-dropping.  The plumes are down quite a ways, in cold water - which is why they are degrading so slowly.  If Alcanivorax borkumensis don't normally live and operate at the depth of the plumes, it would be no surprise to find none in the plumes.