Dissolution of CaCO

Dissolution of CaCOs is a congruent reaction the entire mineral is weathered and results completely in soluble products. The above reaction is driven to the right by an increase of CO2 partial pressure and by the removal of the Ca and/or bicarbonate. Any impurities present in the calcareous rock, such as silicates, oxides, organic compounds, and others, are left as residue. As the calcium and bicarbonate leach... 

Respiration of organic matter and dissolution of CaCOs are the main controls of the distribution of deep ocean Total CO2 and alkalinity. These reactions (and their predicted effects on DIC and alkalinity) can be represented schematically as... 

One of the consequences of dissolution of CaCOs in pore waters is that it creates an... 

I say upper limit because once this amount of CaCOs has been dissolved, the upper 8 cm of the sediment would consist entirely of a noncarbonate residue. As molecular diffusion through such a thick residue would be extremely slow, the rate of dissolution of CaCOs stored beneath this CaCOs-free cap would be minuscule, and further... 

A schematic representation of the approximate flow of carbon during weathering. The figure is a representation of the fluxes in Table 2.1, which suggest that about 2/3 of the HCO produced by weathering via the reactions in Table 2.2 comes from the atmosphere and 1/3 is from dissolution of CaCOs rocks. 

Observations from benthic flux experiments in which Ai and Ca fluxes have been measured both below and above the calcite saturation horizon confirm the effect of organic matter degradation on the dissolution of CaCOs in most but not all situations. Jahnke and Jahnke... 

Dissolution of CaCOs below the photic zone, i.e. the above reaction in reverse, is therefore a net sink for CO2 and recent studies (e.g. Milliman et al. 1999) have suggested that significant dissolution may be coupled with organic matter respiration at shallower depths in the ocean i.e. above 1000 m -potentially providing an important sink for anthropogenic CO2 on short-term timescales. 

An important property of standard free energy changes, AG°, is that they are additive. For example, if in two reactions the product of one reaction serves as a reactant in the other, the AG value for the combined reactions is the sum of the AG° values of the two reactions. In our previous example of the dissolution of CaCOs in acid, we wrote the equation CaC03(s) + Ca + HCOa". In the strict chemical sense this overall... 

Shredding followed by partial dissolution of CaCOs with add [1087]. 

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