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Re: Where does methane come from?

Posted: Sun Nov 15, 2009 4:56 pm
by Nanohedron
I'm still trying to figure out why I gotta worry about the carbon.

Re: Where does methane come from?

Posted: Sun Nov 15, 2009 6:15 pm
by fearfaoin
Pammy wrote:I, and obviously the scientists, don't know exactly where the methane comes from. It can't just be magic'd into existence. Alchemy or what?
It's Chemistry'd into existence. "Methane" is
the name we give the molecule CH4, which
means there is one carbon atom bonded to
four Hydrogen atoms. Carbon and Hydrogen
atoms are in us and the food we eat and the
bacteria in our digestive systems, but those
atoms are bound up in other molecules, like
glucose and DNA. So, the methane isn't in
the grass the cows eat, but the building
blocks to make the methane is.

We (or bacteria) use chemical reactions to
break down the large molecules in food into
other, smaller molecules that cells can use.
As a result of these chemical reactions, less
useful small molecules, like methane, are
created. Since we don't have a use for those,
we have to excrete them.

It's like saying "Is a bookcase in a tree?"
No, but the stuff to make a bookcase is in
the tree.

Re: Where does methane come from?

Posted: Sun Nov 15, 2009 7:56 pm
by emmline
fearfaoin wrote: It's like saying "Is a bookcase in a tree?"
No, but the stuff to make a bookcase is in
the tree.
Good point. Or: "Hey. This isn't a cake! It's just sugar, flour, oil, baking powder and eggs! Where do cakes come from?"

Re: Where does methane come from?

Posted: Sun Nov 15, 2009 8:03 pm
by SteveShaw
Methane is an odourless, colourless, non-toxic gas, which is produced mostly as a result of anaerobic decay of organic matter. It is formed on or below the earth's surface (and in the guts of animals) - it's a constituent of natural gas, found with oil deposits - and once it's released into the atmosphere it gets into the upper regions by convection, mostly at the tropics. It is a very potent greenhouse gas, each molecule having many times the heat-trapping potential of that of a carbon dioxide molecule. Oxygen and water vapour are the enemies of methane, and the gas gradually breaks down in the atmosphere by oxidation processes. The amount of methane in the atmosphere has risen dramatically in the last couple of hundred years. Human contributions are mostly to blame, landfill sites and the proliferation of herbivorous farm animals being significant culprits. Any other process of decay that excludes oxygen is also likely to produce methane, even your compost heap, so things such as slurry lagoons, silage heaps and manure dumps will contribute significantly. The odour of a nice ripe f*rt is nothing to do with the methane present. You need to look in the direction of various sulphurous compounds to explain that. And I should add that methane cannot be regarded as an excretory product of humans or farm animals, any more than dietary fibre can, as it is not produced by metabolic processes within cells.

Re: Where does methane come from?

Posted: Sun Nov 15, 2009 9:11 pm
by chas
I remember seeing in Science, probably about 15 years ago, that some people (and presumably other mammals) have gut flora that produce hydrogen instead of methane. IIRC, these folks had lower rates of some types of cancer due to the extreme anti-oxidant properties of hydrogen. There was also some talk about trying to introduce those microbes into cows to reduce the amount of methane produced by ranching. I haven't heard anything since.

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 7:19 am
by talasiga
chas wrote:...... I haven't heard anything since.
How on earth do you manage music?

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 12:05 pm
by oleorezinator

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 12:50 pm
by Pammy
chas wrote:I remember seeing in Science, probably about 15 years ago, that some people (and presumably other mammals) have gut flora that produce hydrogen instead of methane. IIRC, these folks had lower rates of some types of cancer due to the extreme anti-oxidant properties of hydrogen. There was also some talk about trying to introduce those microbes into cows to reduce the amount of methane produced by ranching. I haven't heard anything since.
I wonder if people with stinky wind have a higher incidence of cancer?

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 12:54 pm
by Pammy
fearfaoin wrote:
Pammy wrote:I, and obviously the scientists, don't know exactly where the methane comes from. It can't just be magic'd into existence. Alchemy or what?
It's Chemistry'd into existence. "Methane" is
the name we give the molecule CH4, which
means there is one carbon atom bonded to
four Hydrogen atoms. Carbon and Hydrogen
atoms are in us and the food we eat and the
bacteria in our digestive systems, but those
atoms are bound up in other molecules, like
glucose and DNA. So, the methane isn't in
the grass the cows eat, but the building
blocks to make the methane is.

We (or bacteria) use chemical reactions to
break down the large molecules in food into
other, smaller molecules that cells can use.
As a result of these chemical reactions, less
useful small molecules, like methane, are
created. Since we don't have a use for those,
we have to excrete them.

It's like saying "Is a bookcase in a tree?"
No, but the stuff to make a bookcase is in
the tree.
Now that explains it better. The bacteria somehow combine the carbon and hydrogen atoms in their - whatever they do - and that is where the methane comes from? Is that it?

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 1:11 pm
by dwest
Pammy wrote:
chas wrote:I remember seeing in Science, probably about 15 years ago, that some people (and presumably other mammals) have gut flora that produce hydrogen instead of methane. IIRC, these folks had lower rates of some types of cancer due to the extreme anti-oxidant properties of hydrogen. There was also some talk about trying to introduce those microbes into cows to reduce the amount of methane produced by ranching. I haven't heard anything since.
I wonder if people with stinky wind have a higher incidence of cancer?
Not if they use a good spring tonic every year. :boggle:

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 1:20 pm
by fearfaoin
Pammy wrote:Now that explains it better. The bacteria somehow combine the carbon and hydrogen atoms in their - whatever they do - and that is where the methane comes from? Is that it?
Something like that, yes. I am neither a
biologist nor a chemist, but that is my
(probably oversimplified) understanding.

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 1:51 pm
by SteveShaw
fearfaoin wrote:
Pammy wrote:Now that explains it better. The bacteria somehow combine the carbon and hydrogen atoms in their - whatever they do - and that is where the methane comes from? Is that it?
Something like that, yes. I am neither a
biologist nor a chemist.
No, but you purport to write like one. See note above, esp. regarding excretion. :really:

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 2:15 pm
by dwest
Pammy just read Walter the Farting dog to understand Farts, and take a walk into a marsh and pull a soil core sample to understand anaerobic digestion. This is where much of the methane in the atmosphere originates. Marshes are full of putrescible substances that are decomposed in the absence of oxygen to produce methane. Termite flatulence is composed of varying levels of methane based on species.

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 2:36 pm
by fearfaoin
SteveShaw wrote:No, but you purport to write like one. See note above, esp. regarding excretion. :really:
wikipedia wrote:Many people misuse the term excretion as a euphemism for defecation, and use excrement for feces, but this is biologically incorrect.
My bad. Nothing more dangerous than
a little knowledge.

Was I at least close in the formation of
methane during digestion?

Re: Where does methane come from?

Posted: Mon Nov 16, 2009 2:47 pm
by crookedtune