Bugs (microbes) in key role of CO2 storage method (!!!)

[OKIsItJustMe]

http://www.ed.ac.uk/news/all-news/130612-bugs

[font face=Serif][font size=5]Bugs in key role of CO2 storage method[/font]

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Scientists have discovered how microbes can be used to turn carbon dioxide emissions into soil-enriching limestone.

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[font size=4]Locking away carbon[/font]

Researchers studied what takes place when the Iroko tree is grown in dry, acidic soil and treated with a combination of natural fungus and bacteria.

They saw that not only does the tree flourish, it also produces the mineral limestone in the soil around its roots - a way of locking up carbon.

The tree makes a mineral by combining calcium from the earth with CO2 from the atmosphere. The bacteria then create the conditions under which this mineral turns into limestone.

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[drm604]

1. Interesting.

I wonder if it's possible to do this on a large enough scale to make a difference.

[longship]

2. As long as it isn't MRSA.

I've got some good news and bad news.

The good news is that we've solved the carbon sequestering problem with a easily reproducible bacteria.

The bad news is that it only replicates in humans and it makes you bleed out internally.

[eppur_se_muova]

3. "by combining calcium from the earth ..." um, this begs the obvious question ...

where, exactly, is this calcium coming from, and in what form? I don't doubt this process is depositing CaCO3 if that's what they're observing, but there's a chance that calcium came from dissolving limestone elsewhere, so no net gain.

As the weathering of limestone (CaCO3) liberates equimolar amounts of Ca2+ and CO2, it has no net effect on the CO2 content of the atmosphere and ocean. The weathering of silicate rocks like granite, on the other hand, is a net CO2 sink because it produces abundant Ca2+ but very little CO2.

http://en.wikipedia.org/wiki/Calcium#Geochemical_cycling

This is such a key point that it bothers me it wasn't mentioned explicitly in the article -- and if it IS converting granite (or other calcium aluminosilicates, possibly silt) into limestone it seems a very odd omission indeed, as this would be presumed to be exactly what they were trying to do from the beginning.

I'm keeping my fingers crossed that this is bad PR by the university and does not adequately reflect the thinking of the researchers.



(Calcium aluminosilicates can be thought of, at least formally, as "composed of" CaO, Al2O3, and SiO2. CaO is basic, the others acidic. The idea is to combine acidic CO2 with the CaO "component", leaving Al2O3 and SiO2 (sand) behind. This would just be doing biologically the same erosional process described in the Wiki.)