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RE: Aquatic Plants Digest V4 #224
Roger said "Photosynthesis does not consume nitrogen."
I've seen a number of texts that re-iterate the following statements -
"From the observed average ratios of the major elemental constituents of
algal biomass we can use 'C106-H263-O110-N16-P' as the 'formula' for algae.
Depending on whether the nitrogen is taken up as nitrate or ammonium ion, we
can write the following two more complete stoichiometric descriptions of
photosynthesis -
106CO2 + 16NO3- + H2PO4- + 122H2O + 17H+ <==> algae + 138O2
or
106CO2 + 16NH4+ + H2PO4- + 106H2O <==> algae + 106O2 + 15H+
These processes which involve the assimilation of cations and anions such as
NH4+ and NO3- affect the alkalinity as a result of the uptake or release of
H+ (or OH-) that is required to maintain charge balance. From the
stoichiometry of these equations we can see that -
- When the major nitrogen source is NH4+, the alkalinity decreases by 15/106
(=0.14) mol per mole of carbon fixed;
- When the major nitrogen source is NO3-, the alkalinity increases by 17/106
(=0.16) mol per mole of carbon fixed.
The pH changes brought about by assimilation or release of phosphate &
nitrogen are usually quite small compared to those due to CO2 exchange."
The above information can be found on pages 19-20 of
http://www.sfu.ca/chemcai/pdf/c3carb.pdf
<http://www.sfu.ca/chemcai/pdf/c3carb.pdf> (see also
http://antoine.frostburg.edu/chem/senese/webwork/hmco/chemed-l/199805/msg000
20.html
<http://antoine.frostburg.edu/chem/senese/webwork/hmco/chemed-l/199805/msg00
020.html> for the original link).
Can anyone confirm if this is (or isn't) correct (or relevant!)?
Kevin
-----Original Message-----
Date: Sun, 16 Apr 2000 14:06:02 -0600 (MDT)
From: "Roger S. Miller" <rgrmill at rt66_com>
Subject: Re: Reverse Photoperiod
On Sun, 16 Apr 2000, Moontanman wrote:
> Some bacteria and algae can, when deprived of light, switch to
> chemosynthesis but this is not nearly as efficient in consuming
> nitrogen as photosynthesis.
Photosynthesis does not consume nitrogen.
Roger Miller
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