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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]
Specifically, it is the deep waters that are undersaturated with calcium carbonate primarily because its solubility increases strongly with increasing pressure and salinity and decreasing temperature. As the atmospheric concentration of carbon dioxide continues to increase, the CCD can be expected to decrease in depth, as the ocean's acidity ...
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]
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 ...
The structures and arrangements of mollusc shells are diverse, but they share some features: the main part of the shell is crystalline calcium carbonate (aragonite, calcite), though some amorphous calcium carbonate occurs as well; and although they react as crystals, they never show angles and facets. [16]
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.
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.
The calcite in the Great Calcite Belt is formed by tiny marine organisms called coccolithophores, which build their shells out of calcium carbonate. When these organisms die, their shells sink to the bottom of the ocean, and over time, they accumulate to form a thick layer of calcite sediment.