If I remember the chemistry of this correctly, HCO3 and CO2 are in
equilibrium in water. The direction of the equilibrium depends on
KH, pH, and temperature.
> Mark, you brought up a point most people don't consider about CO2 as a
> "fuel" molecule for aquatic photosynthesizers--there's evidence that some
> (many?) aquatic systems can use bicarbonate ions, HCO3-, as an initial
> source for photosynthesis. Peak demand for CO2 in an aquatic system can
> remove CO2 from the water, say in early afternoon on a hot day with bright
> sunshine; _everything_ green is sucking in CO2 as fast as they can find it,
> and CO2 is not especially water soluble. So, use the next best
> thing--bicarbonate ions, which will be relatively common in water as it
> becomes more basic from losing dissolved CO2 (source of carbonic acid). My
> understanding is that the bicarbonate can be enzymatically changed to CO2
> inside the cell.
>
> So, maybe don't follow fashion and fight a losing battle to hypersaturate
> your waters with CO2, but develop a steady source in your tank for
> bicarbonate ions (which are much more water soluble than CO2).
>
> Just a thought...
>
> --Bruce Stallsmith
> Huntsville, AL
>
> >Speaking from complete ignorance, I would make two observations -- First, I
> >would expect that CO2 as a carbon source would be irreplaceable. Any plant
> >physiologists out there? If these additives can produce dissolved CO2 in
> >the water, then that's all you need, right? I guess another possible
> >carbon source would be that which is used in tissue culture, where
> >carbohydrates are fed to the plants directly. This has to be done in
> >sterile conditions so that the carbohydrates are not consumed by
> >microorganisms. Still, you don't get normal plant growth without
> >photosynthesis, which as far as I know, requires CO2 (carbon dioxide gas).
> >Second, my suggestion for adding CO2 would be by adding fish or other
> >respiring aquatic creatures. Perhaps air breathing fishes would be
> >preferable, since they don't require high oxygenation and, as far as I
> >know, release CO2 via their gills, directly into the water. Anyone know
> >whether air breathing fishes use the atmosphere to release CO2? Hmm, never
> >thought about that! So, here's a new idea (as far as I know) -- fill your
> >planted tanks with mudminnows or anabantids!
> >
> >Need budminnows? Visit...
> >http://jonahsaquarium.com/
> >
> >Mark
> >Columbus Ohio USA <))><
> >mbinkley_at_columbus.rr.com
>
> _________________________________________________________________
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>
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Prost,
Martin
Jackson, MS
-----------------------------------------------------------
Whenever I see an old lady slip and fall on a wet sidewalk,
my first instinct is to laugh. But then I think, what if
I was an ant, and she fell on me. Then it wouldn't seem
quite so funny.
/-----------------------------------------------------------------------------
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
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/ For more information about NANFA, visit our web page, http://www.nanfa.org