Re: Carbonate deposition (formerly oil, etc.)

On Wed, 26 Nov 2003 17:56:46 -0500 "bivalve"
<bivalve@mail.davidson.alumlink.com> writes:
> >> Technical point: If organisms take CaCO3 out of solution, then
> more CaCO3 will go into solution, where water contacts limestone
> (LS), and thereby allow additional organisms to take additional
> CaCO3 out of solution. This process can go on in principle until
> the oceans are saturated with such organisms (whatever that means).
> But as soon as they die, their skeletons will be available to
> contribute to the CaCO3 in solution.<<
>
> It's a bit more complicated than that. Dissolved carbonate is in
> equilibrium with bicarbonate, carbonic acid, and dissolved carbon
> dioxide. Thus, pH and carbon dioxide concentrations have major
> impacts on the amount of carbonate available to organisms to
> precipitate.

There is another complication. My /Van Nostrand's Scientific
Encyclopedia/ lists 404 g per metric ton of Ca in sea water, and 27.6 of
C. As I calculate it, if all the C were in CaCO3, that would require only
about 92 g of Ca out of the 404. So most of the Ca must be in other
states. Of course, one expects the compounds in solution to be primarily
in the form of ions. So the assumption of lime in/lime out bears no
relation to reality.
Dave
Received on Wed Nov 26 21:29:54 2003