Reef Chemistry Question of the Day #118 Carbonate species

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #118

What is the rank order of carbon dioxide species in seawater at pH 8, from highest concentration to lowest? (> means greater than)


A. Carbonate > bicarbonate > carbon dioxide/carbonic acid
B. Bicarbonate > carbonate > carbon dioxide/carbonic acid
C. Carbonate > carbon dioxide/carbonic acid > bicarbonate
D. Bicarbonate > carbon dioxide/carbonic acid > carbonate

Good luck!




























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[fuzzone99]

Great Question

Gotta go with B.

 

[beaslbob]

I have no idea and Randy is avoiding c now.

 

[JimWelsh]

B. See: ORNL/CDIAC-105

 

[fuzzone99]

B. See: ORNL/CDIAC-105

Wow. Nice reference. Haven't read it yet, but it goes to show how complex carbonate chemistry can be. Also how important it is in the ocean.
Thanks Jim!

 

[Randy Holmes-Farley]

And the answer is...B. Bicarbonate > carbonate > carbon dioxide/carbonic acid

Here's a graph of mine of the relative concentration of these species as a function of pH:

http://reefkeeping.com/issues/2006-10/rhf/index.php

from it:

Relative fraction of carbon dioxide and carbonic acid (black), bicarbonate (white) and carbonate (red) in seawater as a function of pH.