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Calcium carbonate saturation can be determined using the following equation: Ω = ([Ca 2+][CO 3 2−])/K sp. where the numerator ([Ca 2+][CO 3 2−]) denotes the concentration of calcium and carbonate ions and the denominator (K sp) refers to the mineral (solid) phase stoichiometric solubility product of calcium carbonate. [8]
The lysocline is the depth in the ocean dependent upon the carbonate compensation depth (CCD), usually around 5 km, below which the rate of dissolution of calcite increases dramatically because of a pressure effect. While the lysocline is the upper bound of this transition zone of calcite saturation, the CCD is the lower bound of this zone.
The carbonate compensation depth (CCD) is the depth, in the oceans, at which the rate of supply of calcium carbonates matches the rate of solvation. That is, solvation 'compensates' supply. Below the CCD solvation is faster, so that carbonate particles dissolve and the carbonate shells of animals are not preserved. Carbonate particles cannot ...
Biogenic calcium carbonate is formed when marine organisms, such as coccolithophores, corals, pteropods, and other mollusks transform calcium ions and bicarbonate into shells and exoskeletons of calcite or aragonite, both forms of calcium carbonate. [57] This is the dominant sink for dissolved calcium in the ocean. [114]
Shell growth in estuaries is an aspect of marine biology that has attracted a number of scientific research studies. Many groups of marine organisms produce calcified exoskeletons, commonly known as shells, hard calcium carbonate structures which the organisms rely on for various specialized structural and defensive purposes.
[11] [12] At the same time, the biogenic precipitation of calcium carbonate during coccolith formation reduces the total alkalinity of seawater and releases CO 2. [ 13 ] [ 14 ] Thus, coccolithophores play an important role in the marine carbon cycle by influencing the efficiency of the biological carbon pump and the oceanic uptake of ...
An aragonite sea contains aragonite and high-magnesium calcite as the primary inorganic calcium carbonate precipitates. The reason lies in the highly hydrated Mg 2+ divalent ion , the second most abundant cation in seawater after Na + , known to be a strong inhibitor of CaCO 3 crystallization at the nucleation stage.
Carbonate ions preferentially bind to hydrogen ions to form bicarbonate, [10] thus a reduction in carbonate ion availability increases the amount of unbound hydrogen ions, and decreases the amount of bicarbonate formed (Equations 1–3). pH is a measurement of hydrogen ion concentration, where a low pH means there are more unbound hydrogen ions ...