The lysocline is a term used in geology, geochemistry and marine biology to denote the depth in the ocean below which the rate of dissolution of calcite increases dramatically. Geology (from Greek γη- (ge-, the earth) and λογος (logos, word, reason)) is the science and study of the Earth, its composition, structure, physical properties, history and the processes that shape it. ... The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the Earths chemical components in time and space, and their interaction with... Marine biology is the Scientific study of the plants, animals and other organisms that live in the ocean. ... [[Image:http://www. ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ...

Shallow marine waters are generally supersaturated in calcite, CaCO₃, so as marine organisms (which often have shells made of calcite or its polymorph, aragonite) die, they will tend to fall downwards without dissolving. As depth (i.e. pressure) increases within the water column, the corresponding calcite saturation of seawater decreases and the shells start to dissolve. The reaction involved is CaCO₃(s) + H₂O + CO₂ → Ca²⁺(aq) + 2HCO₃^-(aq). At the lysocline, the rate of dissolution increases dramatically. Below this, there exists a depth known as the carbonate compensation depth (CCD) below which the rate of supply of calcite equals the rate of dissolution, such that no calcite is deposited. This depth is the equivalent of a marine snow-line, and averages about 4,500 meters below sea level. In biology and ecology, an organism (in Greek organon = instrument) is a living complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole. ... In general, a polymorph is something that can exist in several states or forms. ... Aragonite Aragonite is a polymorph of the mineral calcite, both having the chemical composition CaCO3. ... Sea water is water from a sea or ocean. ... Carbonate compensation depth (CCD) is a level in the oceans below which the rate of supply of calcium carbonate (calcite and aragonite) equals the rate of dissolution, such that no calcium carbonate is preserved. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ...

The depth of the CCD varies as a function of the chemical composition of the seawater and its temperature. Furthermore, it is not constant over time, having been globally much shallower in the Cretaceous through to Eocene. If the atmospheric concentration of carbon dioxide continues to increase, the CCD can be expected to rise, along with the ocean's acidity. The Cretaceous period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic period, about 146 million years ago (Ma), to the beginning of the Paleocene epoch of the Tertiary period (65. ... The Eocene epoch (56-34 Ma) is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ...

See also

• Biological pump
• Ocean acidification