Thursday, 5 August 2010

That oil spill ..

A few weeks ago I urged everyone to put the Gulf oil spill in context;
The volume of the Gulf of Mexico is 2,424,000 cubic kilometers, or 6.43 * 1017 US gallons. The volume of oil spilt is estimated at 20m gallons to 50m US gallons; let's take the max, 5 * 107 gallons. That's one part of oil to 1.29 * 1010 parts of water.

The volume of the Thames at mid tide between Teddington and Gravesend is about 2.4 * 107 cubic metres (633 * 107 US gallons, or 127 times the total volume of the BP oil leaked). To replicate the 'environmental disaster' the Septics are claiming, I'll therefore have to empty 1.87 litres of engine oil into the river.
Now it appears that 75% of the oil has evaporated and a further 24% has been eaten by bacteria. The Armageddon merchants have crawled back in their (unpolluted) shells and the talk has switched to 'undetectable long term damage'

Whatever. The fact remains that 1 part of oil to 100,000,000,000 parts of water is nothing to get excited about.


Tufty said...

I've seen a number of calculations like this and I'm not surprised the damage was far less than the hype. Oil is a natural product and surprisingly biodegradable in water.

I wonder what 'undetectable long term damage' is. Not easy to quantify is it?

talwin said...

I know what you mean but still I'd rather not think of Obama as an 'Armageddon merchant'.

Anonymous said...

And now, to cap (sic) it and crustacia may actually benefit from all this coz those nice "oil eating" microbial life forms will flourish and guess what feeds on them? Fish and crustacia! Brilliant Sherlock! Open that well again will you, its time for lunch!

Coney Island

Demetrius said...

Apparently the ban on fishing is alleged to be helping to rebuild fish stocks. I'll have the olive oil dressing, please.

thefatlady said...

To quote one Tony Hayward "A drop in the ocean".

measured said...

Oil does rise to the top though and it is not transparent,

...just as cream rises to the top.
Blair/Brown? akin to the oil than the cream. Cameron? early days.

Gallimaufry said...

Homeopathically, that dilution is very powerful. Thank goodness the same quantity didn't escape into the Atlantic!

Katabasis said...

Interesting points all.

mamapajamas said...

@: "Anonymous
Coney Island
5 August 2010 11:53"

LOL! One of the things I've been saying from the start is that one of the outcomes of all of this will be "fat shrimp".

That got me sneered at and clucked at as "insensitive", even though I live in the Florida Gulf region.

The biggest long-term disaster here has been the media hysteria, which has kept tourists away from our sugar-white beaches.

Bill Sticker said...

24% eaten by 'oil eating bacteria'? Okay, I'll bite; anyone know what species? That's thousands(?) of tonnes of oil being reduced very quickly by bacterial action over a relatively short timescale. The oil is / has disappeared. Yet forgive me for being dense, but are you sure there aren't other processes responsible?

Is there a microbiologist in the house?

sdcougar said...

Aha, but you fail to recognize that all this oil that has evaporated and been eaten is do to the prompt action of the White House. They said so:

"A significant amount of this is the direct result of the federal government's aggressive response to the spill."

Leg-iron said...

Can't give a species name off the top of my head, but back in about 1982 I worked briefly on a project that aimed to use bacteria to degrade spilled oil. I left before it ended but I think it fizzled out when it became clear that the bacteria concerned were already in the sea anyway.

As for tonnage, well bacteria are small but there are a hell of a lot of them. Water that looks perfectly clear could have ten thousand bacteria per ml. They are also, in many cases, very fast at metabolising and with lots of food around, they can grow fast too. Oh, and they don't sleep or take days off. They'll be breaking down that oil 24/7.

There'll always be some oil-degrading bacteria in the sea, and there'll be more of them in areas where shipping is common. Warm conditions, as in the Gulf, coupled with a sudden boost to the food supply for these bacteria, and they'll reproduce extremely quickly.

When the oil is used up the bacteria will die back, they'll be eaten by plankton and the food chain will recover.

Nature isn't worried about this oil leak. The Gulf isn't worried. The bacteria are delighted and shortly, the rest of the food chain will be too.

The only ones working themselves into a hysterical frenzy are the Green loons.

mamapajamas said...

@Bill Stickler,7 August 2010 16:59

Bill, yes, a good 24% of the oil could have easily been consumed by microbes in the Gulf.

Point of fact: We have here an estimated 200,000 gallons of oil leeching up from natural fissures daily. We also have megatons of dirty shipping passing through our waters en route to and from Biloxi and New Orleans and other harbors.

So where does all the oil go-- even under normal circumstances? Why are our Gulf coast beaches famous for their sugar-white sand instead of their tarballs?

Answer: The hydrocarbon-consuming microbes that were out there from the get-go already had a rich diet, and then expanded rapidly to fit into their new oil-rich environment. Why are you having a problem with this?

Also, just FYI, salt water isn't very good for oil, either. I don't recommend using it to clean your engines. ;)

Anonymous said...

A few quibbles with this excellent post.

While up to 75% of very light, sweet crude could evaporate at the surface, the oil from the MC252 well was a bit heavier and up to 45% could evaporate at the surface.

However, as the released oil had to travel a mile to the surface and much of it emulsified or dispersed at depth, only about 25% of the oil evaporated, (according to the NOAA.)

The oil that did reach the surface, was mixed with water and formed ropey globs. Thus there was far less of a surface area in contact with the atmosphere than is the case in a release closer to the surface in which the oil forms a large, thin slick.

NIC:Deepwater Horizon Oil Budget

This would be my other quibble with Raewald's calculation. The point is not the quantity of the oil released, rather, where it is released. The oil will always be a tiny fraction of the larger volume of sea water.

Oil released near the surface, or in shallow water will, slick and cause far more immediate impact. Oil released in the warm gulf waters where there are plentiful oil consuming organisms from all the natural seeps, will also deteriorate rapidly. Likewise, we see from this spill that oil released 5,000' beneath the waves will emulsify and disperse, then degrade quickly. Far less of a problem in these deep-water regions far from the rich tidal zones.

The same spill in 50' of water near the coast would have devastated that area, though it would of course recover in 1 to 3 years. The lesson learned should Drill Deep and far from shore, not a moratorium.


Anonymous said...

You don't need shipping to encourage oil eating microbes in the GoM. Naturals seeps account for between one-third and one-twelfth of the amount of oil that the Deepwater Horizon well was leaking. There are always plenty of oil eating microbes in the Gulf of Mexico.

mamapajamas said...

@ Anonymous said... 8 August 2010 00:40

"The same spill in 50' of water near the coast would have devastated that area, though it would of course recover in 1 to 3 years. The lesson learned should Drill Deep and far from shore, not a moratorium."

The same spill in shallow water could have been fixed by a dozen scuba divers in a few days, therefore there would not have been anywhere near the oil spilled in the first place.

The depth of the well was the problem from the get-go.

Anonymous said...

Mamapajamas said:
"The same spill in shallow water could have been fixed by a dozen scuba divers in a few days, therefore there would not have been anywhere near the oil spilled in the first place.

The depth of the well was the problem from the get-go."

Lol, scuba divers?

Google the Ixtoc I spill in the GOM. It was only 160' deep and it took 10 months and several relief well attempts to stop.

On June 3, 1979, the 2 mile deep exploratory well, IXTOC I, blew out in the Bahia de Campeche, 600 miles south of Texas in the Gulf of Mexico. The water depth at the wellhead site is about 50 m (164 feet). The IXTOC I was being drilled by the SEDCO 135, a semi-submersible platform on lease to Petroleos Mexicanos (PEMEX). A loss of drilling mud circulation caused the blowout to occur. The oil and gas blowing out of the well ignited, causing the platform to catch fire. The burning platform collapsed into the wellhead area hindering any immediate attempts to control the blowout. PEMEX hired blowout control experts and other spill control experts including Red Adair, Martech International of Houston, and the Mexican diving company, Daivaz. The Martech response included 50 personnel on site, the remotely operated vehicle TREC, and the submersible Pioneer I. The TREC attempted to find a safe approach to the Blowout Preventer (BOP). The approach was complicated by poor visibility and debris on the seafloor including derrick wreckage and 3000 meters of drilling pipe. Divers were eventually able to reach and activate the BOP, but the pressure of the oil and gas caused the valves to begin rupturing. The BOP was reopened to prevent destroying it. Two relief wells were drilled to relieve pressure from the well to allow response personnel to cap it. Norwegian experts were contracted to bring in skimming equipment and containment booms, and to begin cleanup of the spilled oil. The IXTOC I well continued to spill oil at a rate of 10,000 - 30,000 barrels per day until it was finally capped on March 23, 1980.


No doubt the depth was a complication, but in the case of MC252, it was also a tremendous advantage as it kept the raw crude far from shore.