The carbon dioxide cycle goes through the hemispheres of the earth for example: biosphere, pedosphere, geosphere, hydrosphere, and the atmosphere around the earth. The terrestrial biosphere that is usually defined to include fresh water system. Carbon circles around the earth. The test method for carbon is an acidbase titration,meaning that a certain base is added to the sample until it nuetralizes all the acid in the sample and brings the p.h. up to 8.3.Carbon dioxide in water is an acid , so it is titrated by the base. But any other acid in the sample will also be titrated by the base, including the humic acid in your sample. Also only bases already in the the sample will affect the titration.

this is the carbon cycle

This is Carbon Dioxide in 3-D

Carbon dioxide equation

CO2 (g) + H20 = H2CO3(ag) which makes carbonic acids

H2CO3 <=>H+CO3. Plus if you have calcium in the carbon dioxide you get

CA + CO = calcium carbon

( CA = calcium) And thats the carbon eqaution.