Theoretical considerations about the reactions of calcification in sea water

We examine the concentration variations of the different parameters X of the carbonate system in seawater when calcium carbonate precipitation occurs. Variations are expressed as ∂[X]/∂[Ca2+]. Four different cases are considered: spontaneous chemical precipitation; calcification combined with photosynthetic activity under a constant ΔCT/Δ[Ca2+] ratio; precipitation under constant pCO2 and precipitation under constant [Ca2+]•[CO32−] ionic concentration product. The last condition should be maintained by an ecosystem which, thanks to the regulation of its calcifying and photosynthetic activity, would absorb 1 mol of carbon for organic tissue each time 1 mol of CaCO3 is formed. This stoichiometric ratio would allow the activity of these biological communities to go on in practically closed systems during periods compatible with their growth or development cycles.