Carbon Cycle Question

[Phil Sheppard]

I am trying to find out where the carbon in oil, coal and gas would have gone eventually if we had not excavated and used it, so I would be grateful if a climate scientist could tell me if the following is correct. I have searched the 2007 IPCC report but have not found an answer there:

 

1. Trees and other plants which died and were then squashed and degraded to make oil, coal and gas took CO2 out of the atmosphere when they grew.

 

2. Under a natural cycle covering tens of millions of years, the oil, coal and gas would have degraded back to elements and compounds useful to life and been taken up by plants. Carbon would have been incorporated in those compounds.

 

3. Some of the carbon would therefore have been released as CO2 when metabolised and exhaled by people and animals eating the plants. (The remainder would have stayed in the soil for use by new plants as structural material.)

 

4. What we are therefore doing by burning the oil, coal and gas in large quantities is (a) speeding up the whole carbon cycle very considerably and (b) releasing more carbon into the atmosphere from oil, coal and gas than would have happened naturally because we are using it for more than just metabolism, and not using it for structural functions.

[Mokele]

That's actually an interesting question: in a natural system, without humans, what happens to oil? Plants won't use it, because they get their carbon from atmospheric CO2. Animals sure won't. The only naturally accessible points I can think of are tar pits.

[insane_alien]

bacterial digestion? geological activity would likely bring it to the surface at some point where bacteria could get access to it.

[Psycho]

bacterial digestion? geological activity would likely bring it to the surface at some point where bacteria could get access to it.

Wouldn't think so that would most likely require some enzyme that would have been exploited by now to create oil from biomass, this of course presumes that the bacteria can be isolated and grown.

 

There won't be much evidence supporting that idea however, it probably would occur due to evolution.

[insane_alien]

it already does, happens all the time in waste treatment plants albeit with more digestible hydrocarbons but the bacteria used first adapt a tolerance to the presence of the hydrocarbons and then theyend up using it as a carbon source for cell material and energy.

 

so, after an earthquake and several millions of gallons of crude bubble up from the sea floor something will end up feasting on it.

 

of course on land it is somewhat harder to do as the concentration is immense

[Psycho]

it already does, happens all the time in waste treatment plants albeit with more digestible hydrocarbons but the bacteria used first adapt a tolerance to the presence of the hydrocarbons and then theyend up using it as a carbon source for cell material and energy.

 

so, after an earthquake and several millions of gallons of crude bubble up from the sea floor something will end up feasting on it.

 

of course on land it is somewhat harder to do as the concentration is immense

Alkane polymers can hardly be compared to biologically created sugar molecules and there polymers, if it were as simple as that all you would need is some oil, bacteria and a mutagen and you could mutate it to create an enzyme that could be reversed to create hydrocarbons from sugar. In reality they would just become resistant to the chemicals through mutation.

[insane_alien]

did i say they were grown on sugars? no.

 

you can grow them on pretty much any organic waste, i'm currently writing up specs for an aerobic digester to handle the effluent stream of guess what? an ethylene plant.

 

the effluent stream mainly consists of longer chain hydrocarbons that didn't get converted C4-9 along with water, and other impurities. no sugars involved except in the innoculate.

 

the bacteria involved(i'm not sure of the name as someone better versed in biology than me is handling that, but she assures me it exists) was initially grown on a sugar medium and was adapted to digest alcohols before finally moving onto alkanes via a alcohol/alkane mix.

 

the end product is a bacteria that can digest alkanes with no problems. just need to give it the right supplements to keep it alive and ensure adequate dilution(addition of emulsifiers so the alkanes don't seperate out before anyone thinks i'm claiming alkanes and water are miscible). but it handles 300g/m^3 fine. This is a hypothetical project though and it will never be built but the mechanism is there.

[Psycho]

did i say they were grown on sugars? no.

 

you can grow them on pretty much any organic waste, i'm currently writing up specs for an aerobic digester to handle the effluent stream of guess what? an ethylene plant.

 

the effluent stream mainly consists of longer chain hydrocarbons that didn't get converted C4-9 along with water, and other impurities. no sugars involved except in the innoculate.

 

the bacteria involved(i'm not sure of the name as someone better versed in biology than me is handling that, but she assures me it exists) was initially grown on a sugar medium and was adapted to digest alcohols before finally moving onto alkanes via a alcohol/alkane mix.

 

the end product is a bacteria that can digest alkanes with no problems. just need to give it the right supplements to keep it alive and ensure adequate dilution(addition of emulsifiers so the alkanes don't seperate out before anyone thinks i'm claiming alkanes and water are miscible). but it handles 300g/m^3 fine. This is a hypothetical project though and it will never be built but the mechanism is there.

If this is such why has no one come to you with great interest in isolating the enzyme pathway involved as give enough of a certain substrate and essential, or what would be classed as essential under normal condition, gene knock out could the organism not be used to create fuels due to the reversible equilibrium that occurs with enzyme kinetics.

 

Of course ethanol can already be created but I have heard of no bacteria being able to create longer hydrocarbon chains in any economically viable fashion, especially not in nature, or the opposite of catalysis for energy.

[insane_alien]

probably because i am not carrying out research in this field. and am unlikely to ever carry out research in this field. i do not know the enzyme pathways all i know is that it takes alkanes and uses them as a carbon source for making cell material and energy and that it was genetically engineered somewhere(germany i think). and i am unaware of any reversibility of this. i'm pretty sure that it is fairly irreversible, enzyme or no enzyme.

[Mokele]

Psycho -

 

Microbes naturally exist which feed on oil seeps

 

and we've completely sequenced the genome of one of these bacteria

[CharonY]

What we are therefore doing by burning the oil, coal and gas in large quantities is (a) speeding up the whole carbon cycle very considerably and (b) releasing more carbon into the atmosphere from oil, coal and gas than would have happened naturally because we are using it for more than just metabolism, and not using it for structural functions.

 

Well that and the fact that IIRC the metabolisation of crude oil required a dioxygenase at some point, (i.e. the process is aerobic) and also very slow and rather inefficient.

 

As after all this time there are still oil reserves it indicates either that the bacteria able to metabolize them are pretty young (but there is not much evidence for that) or that their metabolization rate is overall lower than the actual production rate.

So without further involvement it is likely that the oil pool would slowly increase over time whereas the bacterial activity would only slow down the process. Human activities on the other hand utilize the pools faster than they are regenerate so they are not only accelerating a process, but in fact reversing it.

[CaptainPanic]

I believe that the most important reason that oil and gas are still around is that they cannot be converted to another compound without oxygen... or, at least, they are at chemical equilibrium in their local environment. No energy can be gained by a microorganism for growth in that local environment (in that oil field).

 

For example: anaerobic processes often have methane as a waste product. But in the gas fields, there is only methane. Unless oxygen would be present (and it's not), there is nothing to eat for the micro organisms.

The same goes for the others: coal and oil. They cannot react any further.

 

If this is such why has no one come to you with great interest in isolating the enzyme pathway involved as give enough of a certain substrate and essential, or what would be classed as essential under normal condition, gene knock out could the organism not be used to create fuels due to the reversible equilibrium that occurs with enzyme kinetics.

 

Of course ethanol can already be created but I have heard of no bacteria being able to create longer hydrocarbon chains in any economically viable fashion, especially not in nature, or the opposite of catalysis for energy.

 

Butanol can also be made by microorganisms, and with the increasing energy prices, this is considered for industrial applications. These microorganisms are used in "ABE fermentation" with ABE standing for acetone, butanol, ethanol. Those are the 3 products.

[CharonY]

I do not want to complicate matters, but some bacterial consortia can utilize methane under anaerobic conditions (yes, I have been around microbiologists for too long).