Buried fossil soils found to be awash in carbon

May 25, 2014 by Terry Devitt
An eroding bluff on the US Great Plains reveals a buried, carbon-rich layer of fossil soil. A team of researchers led by UW-Madison Assistant Professor of geography Erika Marin-Spiotta has found that buried fossil soils contain significant amounts of carbon and could contribute to climate change as the carbon is released through human activities such as mining, agriculutre and deforestation. Credit: Jospeh Mason

Soils that formed on the Earth's surface thousands of years ago and that are now deeply buried features of vanished landscapes have been found to be rich in carbon, adding a new dimension to our planet's carbon cycle.

The finding, reported today in the journal Nature Geoscience, is significant as it suggests that deep soils can contain long-buried stocks of which could, through erosion, agriculture, deforestation, mining and other human activities, contribute to .

"There is a lot of carbon at depths where nobody is measuring," says Erika Marin-Spiotta, a University of Wisconsin-Madison assistant professor of geography and the lead author of the new study. "It was assumed that there was little carbon in deeper soils. Most studies are done in only the top 30 centimeters. Our study is showing that we are potentially grossly underestimating carbon in soils."

The studied by Marin-Spiotta and her colleagues, known as the Brady soil, formed between 15,000 and 13,500 years ago in what is now Nebraska, Kansas and other parts of the Great Plains. It lies up to six-and-a- half meters below the present-day surface and was buried by a vast accumulation of windborne dust known as loess beginning about 10,000 years ago, when the glaciers that covered much of North America began to retreat.

The region where the Brady soil formed was not glaciated, but underwent radical change as the Northern Hemisphere's retreating glaciers sparked an abrupt shift in climate, including changes in vegetation and a regime of wildfire that contributed to as the soil was rapidly buried by accumulating loess.

"Most of the carbon (in the Brady soil) was fire derived or black carbon," notes Marin-Spiotta, whose team employed an array of new analytical methods, including spectroscopic and isotopic analyses, to parse the soil and its chemistry. "It looks like there was an incredible amount of fire."

The team led by Marin-Spiotta also found organic matter from ancient plants that, thanks to the thick blanket of loess, had not fully decomposed. Rapid burial helped isolate the soil from biological processes that would ordinarily break down carbon in the soil.

Such buried soils, according to UW-Madison geography Professor and study co-author Joseph Mason, are not unique to the Great Plains and occur worldwide.

The work suggests that fossil organic carbon in buried soils is widespread and, as humans increasingly disturb landscapes through a variety of activities, a potential contributor to climate change as carbon that had been locked away for thousands of years in arid and semiarid environments is reintroduced to the environment.

The element carbon comes in many forms and cycles through the environment – land, sea and atmosphere – just as water in various forms cycles through the ground, oceans and the air. Scientists have long known about the carbon storage capacity of soils, the potential for carbon sequestration, and that in soil can be released to the atmosphere through microbial decomposition.

The deeply buried soil studied by Marin-Spiotta, Mason and their colleagues, a one-meter-thick ribbon of dark soil far below the modern surface, is a time capsule of a past environment, the researchers explain. It provides a snapshot of an environment undergoing significant change due to a shifting climate. The retreat of the glaciers signaled a warming world, and likely contributed to a changing environment by setting the stage for an increased regime of wildfire.

"The world was getting warmer during the time the Brady soil formed," says Mason. "Warm-season prairie grasses were increasing and their expansion on the landscape was almost certainly related to rising temperatures."

The retreat of the glaciers also set in motion an era when loess began to cover large swaths of the ancient landscape. Essentially dust, loess deposits can be thick—more than 50 meters deep in parts of the Midwestern United States and areas of China. It blankets large areas, covering hundreds of square kilometers in meters of sediment.

Explore further: The importance of soil carbon conservation in mitigating global climate change

More information: Paper: dx.doi.org/10.1038/ngeo2169

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User comments : 22

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mememine69
1.3 / 5 (15) May 25, 2014
What do you call science's 32 years of "95%" certainty? Anything you WANT it to be, except sustainable in "belief" for another 3 decades. Find us one IPCC warning that says; "will be" or "inevitable" or anything beyond; "could be". So science can be 100% certain the earth is NOT flat but 95% sure CO2 "could" flatten it?

Get ahead of the curve;

*Occupywallstreet now does not even mention CO2 in its list of demands because of the bank-funded and corporate run carbon trading stock markets ruled by politicians.

* "Socialist" Canada killed Y2Kyoto with a freely elected climate change denying prime minister and nobody cared, especially the millions of scientists warning us of unstoppable warming (a comet hit).
nevermark
4.6 / 5 (10) May 25, 2014
Mememine, I had a difficult time understanding your comment. Scientists rarely say things like "inevitable" even for non-controversial topics. However, many climate scientists have made strong statements the current climate change is primarily caused by humans. If you were not aware of that, why are you posting?

Did you feel the wording style of scientists is evidence that CO2 is not a green house gas or that it is not accumulating in the atmosphere? Please be specific, this is a genuine question.
Burnerjack
4.5 / 5 (8) May 25, 2014
Nevermark: Trying to reason or ascertain logic from the capriciously insane is difficult or impossible by the very nature of the implied thought process implied.
Steve 200mph Cruiz
4.4 / 5 (7) May 25, 2014
mememine69
They aren't just throwing out random numbers, those numbers are real quantities. Would you be betting on 1/20 odds when you don't even gain something if you win, just lose when your going to be wrong?
Indiana_Curmudgeon
5 / 5 (3) May 25, 2014
I'm not sure, given the environment, why they wouldn't expect high levels of carbon at the periods they are talking about.
Vietvet
4.5 / 5 (8) May 25, 2014
mememine 69 is a troll. He's been posting the same thing everywhere.
PinkElephant
4.4 / 5 (7) May 25, 2014
mememine 69 is a troll. He's been posting the same thing everywhere.
In that case, it may actually be a bot...
Shootist
1.4 / 5 (10) May 25, 2014
Climate change?

"The polar bears will be fine". - Freeman Dyson
Vietvet
5 / 5 (6) May 26, 2014
NO, mememine is real, though I can't recall his real name. I found him on Face Book after he posted the same whine on the San Diego Union web site. It was a local story but he found while living in Canada.
krundoloss
4.3 / 5 (3) May 26, 2014
Is the amount of "carbon" that is "being released" really a significant contributor to greenhouse gases or climate change?

It is somewhat more interesting, implied by the article, that there were a large number of fires at the end of the most recent ice age. Perhaps there was a drought?
Maggnus
4.3 / 5 (7) May 26, 2014
Climate change?

"The polar bears will be fine". - Freeman Dyson
Freeman Dyson? He said this too:

"No doubt that warming is happening. I don't think it is correct to say "global," but certainly warming is happening. I have been to Greenland a year ago and saw it for myself. And that's where the warming is most extreme. And it's spectacular, no doubt about it. And glaciers are shrinking and so on."

So I guess maybe he could be right, but for different reasons than global warming?

What do you say Shootist? Come on you cowardly troll, which Freeman Dyson are we supposed to believe?
PinkElephant
5 / 5 (6) May 26, 2014
@Shootist,

"No balloon and no aeroplane will ever be practically successful."

-William Thomson, 1st Baron Kelvin

If you *have to* pick a genius scientist as your contrarian idol, a towering giant of Lord Kelvin's stature beats the pants off dinky wee Freeman Dyson.

[P.S. I'll keep re-posting this reply to you, every time you re-post your Dyson shibboleth. I'd encourage everyone else to do the same...]
verkle
1 / 5 (7) May 26, 2014
I would like to see a scientific analysis of the relation of the global flood to loess deposits and the Brady soil. Could have happened in the first few hundred years after the flood.
Rustybolts
5 / 5 (4) May 26, 2014
Damn, I thought we were going to get away with destroying the surface of our planet.
antialias_physorg
5 / 5 (6) May 26, 2014
A few niggles with the article:
organic carbon

Last I checked 'organic chemistry' was defined by 'contains carbon'. So what would constitute 'inorganic carbon'?

that would ordinarily break down carbon in the soil.

Carbon is an element. You can't break it down (except by splitting it and that requires processes not ordinarily found on Earth)

"The polar bears will be fine".

Humans won't. That's the issue.
alfie_null
4.5 / 5 (8) May 26, 2014
I would like to see a scientific analysis of the relation of the global flood to loess deposits and the Brady soil. Could have happened in the first few hundred years after the flood.

Brown-nosing for your god again? His purpose must indeed be unknowable if He uses the likes of you to be a proponent. You do Him harm every time you speak.
jackjump
2.1 / 5 (9) May 26, 2014
We're doomed, we're doomed I tell you. There's pure carbon buried down there under the regular soil and it isn't merely coal. It's pure carbon. Just imagine if that gets loose on the earth. Carbon is the most evil element ever . . . I mean look, we're made of it, you can't get much more evil than that. Farmers will probably plow it up (the evil farmers not the organic kind) and it will evaporate or something and cause a runaway greenhouse effect. We're all gonna die!
Maggnus
4.4 / 5 (7) May 28, 2014
I would like to see a scientific analysis of the relation of the global flood to loess deposits and the Brady soil. Could have happened in the first few hundred years after the flood.
There was no global flood, so there cannot be such an analysis.
Captain Stumpy
5 / 5 (5) May 29, 2014
...scientific analysis of the relation of the global flood...
@verkle
there was no flood. could not have been. see:
1- Species Distribution and Diversity: the animal populations as well as diversity (and known outlier communities like Madagascar and Australia) are scientific proof that there could not have been a global flood, let alone a single point distribution from the flood for repopulation
2- the physics of having a single ark containing 7-14 animals of each species including insects etc AS WELL AS material for feed/hygiene would mean an ark considerably larger than the measurements in the biblical event (or even likely possible given the age-)
3- then there is the plant species... BIG gaping hole there in the bible
4- see this link and read some of the references... http://www.talkor...ark.html

Science works
Caliban
5 / 5 (3) May 31, 2014
We're doomed, we're doomed I tell you. There's pure carbon buried down there under the regular soil and it isn't merely coal. It's pure carbon. Just imagine if that gets loose on the earth. Carbon is the most evil element ever . . . I mean look, we're made of it, you can't get much more evil than that. Farmers will probably plow it up (the evil farmers not the organic kind) and it will evaporate or something and cause a runaway greenhouse effect. We're all gonna die!


@jackjump,

Ever heard of the Dust Bowl?
If similar conditions were to develop again in the US, meters of this soil could be stripped away over large geographic areas(just like in the Dust Bowl), and expose this soot for redistribution, as well, which would tend to decrease surface albedo and increase surface warming.

Also, if exposed, much of this black carbon will recombine into CO2, methane, and carbonic acid, and a number of organic toxins.

And that's fact --not alarmist fiction-- and cause for concern.
howhot2
5 / 5 (2) May 31, 2014
Climate change?

"The polar bears will be fine". - Freeman Dyson


"There are many harsh lessons to be learned from the gambling experience, but the harshest one of all is the difference between having Fun and being Smart."

Hunter S. Thompson

The deniers of Global Warming must be having a lot of Fun gambling with their kid's future when the overwhelming consensus among the Smart is that without change the future is bleak. Well ... Unless we can turn that carbon into Organic Carbon (haha, good one AntiAlias).
howhot2
not rated yet May 31, 2014
Climate change?

"The polar bears will be fine". - Freeman Dyson


"There are many harsh lessons to be learned from the gambling experience, but the harshest one of all is the difference between having Fun and being Smart."

Hunter S. Thompson

The deniers of Global Warming must be having a lot of Fun gambling with their kid's future when the overwhelming consensus among the Smart is that without change the future is bleak. Well ... unless we can turn that carbon into Organic carbon (haha, good one AntiAlias).

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