🚀 go-pugleaf

Newsgroups: sci.geo.fluids,sci.environment 
Subject: Back of the envelope oceanic CO2 calculations
Sender: 
Followup-To: sci.geo.fluids
Organization: Code 916, NASA Goddard Space Flight Center

Hello everyone. Today in Chem class we discussed Henry's Law which relates
the vapour pressure of a gas to the amount that would dissolve in a fluid
solvent for a specific concentration and temperature. For kicks and giggles,
I came back and tried to calculate the amount of CO2 in the oceans, given
that the density was 1 kg/m3 (yep, just pure water) and the volume of the 
ocean was 1.35 x 10^15 m3 (Biogeochemistry, Schlesinger, 1992). I assumed a
CO2 concentration of 380 ppm, for a partial pressure of 0.288 Torr at a 
standard temperature of 298 K and pressure 1 atm. For CO2, the Henry's LAw
constant was 1.25 x 10^6 Torr in pure water (no data on seawater since it
is variable due to saline content), and Henry's Law goes like this:

     partial pressure (CO2)= Henry's Const. x mole fraction (CO2)

Furthermore, the mole fraction was defined as :  # moles CO2/ (# moles CO2  
                                                             + # moles H2O)

Working it all out, the answer I came up with was 1.52 x 10^5 metric tons.
Now recalling that the flux of CO2 into and out of the oceans is a bit 
larger than that... I'm curious as to whether this calculation is way off 
as a result of the lack of variance in temperature and salinity, or if it 
is at least in the neighborhood.

Anyone have any evidence of total oceanic CO2 content? 

***This is not meant as a legitimate estimate, so don't flame me for this!***
    (I'm just curious as to how good or bad this approximation is... I 
       have a big feeling that it stinks, but want to make sure.)

Bryan Hannegan
hannegan@halo.ps.uci.edu
Dept. of Geosciences, University of CA, Irvine