Carbon hydrospheric

The relative amounts of atmospheric carbon, hydrospheric inorganic carbon and lithospheric carbonate carbon are about 1 60 10. The amount of... 

As a possible method of concentrating trace amounts of bioactive organic compounds occurring in the hydrosphere, adsorption properties of various compounds have been explored by employing hydrous metal oxides as the adsorbents. To date, a family of organophosphoms compounds and carbonic acids were adsorbed onto hydrous iron oxide, along with the adsoi ption of monosaccharides onto hydrous zirconium oxide. 

Just as in the case for the hydrosphere, the atmosphere participates in all of the major biogeochemical cycles (except for phosphorus). In turn, the chemical composition of the atmosphere dictates its physical and optical properties, the latter being of great importance for the heat balance of Earth and its climate. Both major constituents (O2, H2O) and minor ones (CO2, sulfur, nitrogen, and other carbon compounds) are involved in mediating the amounts and characteristics of both incoming solar and outgoing infrared radiation. 

This treatment of the carbon cycle is intended to give an account of the fundamental aspects of the carbon cycle from a global perspective. After a presentation of the main characteristics of carbon on Earth (Section 11.2), four sections follow 11.3, about the carbon reservoirs within the atmosphere, the hydrosphere, the biosphere... 

Although the largest reservoirs of carbon are found in the lithosphere, the fluxes between it and the atmosphere, hydrosphere, and biosphere are small. It follows that the turnover time of carbon in the lithosphere is many orders of magnitude longer than the turnover times in any of the other reservoirs. Many of the current modeling efforts studying the partitioning of fossil fuel carbon between different reservoirs only include the three "fast" spheres the lithosphere s role in the carbon cycle has received less attention. 

The carbon cycle is complicated by several reactions that involve CO2. These reactions transfer carbon between the atmosphere, the hydrosphere (Earth s surface waters), and the lithosphere (Earth s crastal solids). The processes that move carbon from one sphere to another are illustrated schematically in the figure below. 

Carbon dioxide is divided between the atmosphere and the hydrosphere. This division strongly favors the hydrosphere, because the large volume of water in the oceans has an immense capacity to absorb CO2. 

Almost all the Earth s carbon is found in the lithosphere as carbonate sediments that have precipitated from the oceans. Shells of aquatic animals also contribute CaC03 to the lithosphere. Carbon returns to the hydrosphere as carbonate minerals dissolve in water percolating through the Earth s crust. This process is limited by the solubility products for carbonate salts, so lithospheric carbonates represent a relatively inaccessible storehouse of carbon. 

The carbon dioxide molecules including a radiocarbon atom are chemically undistinguishable from those of ordinary carbon dioxide, with which it mixes, and eventually, carbon dioxide, including a radiocarbon atom, is homogeneously distributed throughout the earth s atmosphere and hydrosphere. Thus there is a state of constant production, distribution, and decay of radiocarbon, which results in the relative amount of radiocarbon in the atmosphere and hydrosphere remaining constant. In this homogeneously distributed condition, radiocarbon enters the carbon cycle - as the... 

A detailed theoretical study of the properties of the redox system FeS/FeS2 was carried out in the Department of Geosciences of SUNY Stony Brook (Schoonen et al., 1999). The authors conclude that the hypothetical reduction of CO2 (by the FeS/FeS2 redox pair) formulated in Wachtershauser s early work, and the carbon fixation cycle on the primeval Earth associated with it, probably could not have occurred. This judgement is made on the basis of a theoretical analysis of thermodynamic data other conditions would naturally have been involved if CO had reacted rather than C02. It is not known whether free CO existed in the hydrosphere, or if so, at what concentrations. 

The natural cycle of carbon involves compounds of the atmosphere, hydrosphere, lithosphere, and biosphere. A certain difference in the 13C isotope content exists between the samples, depending on their origin. To estimate the deviation from the average value of 13C isotope contents 8(%o) scale is used. The deviation may be calculated by Equation 5.14 ... 

The elements whose isotopes are routinely measured with gas inlet mass spectrometers are carbon (12C and 13C, but not 14C), oxygen (160, 170, l80), hydrogen ( H, 2H, but not 3H), nitrogen (14N and 1SN) and sulphur (32S, 33S, 34). Stable isotopes of H, C, N, O, and S occur naturally throughout atmosphere, hydrosphere, lithosphere, and biosphere. They are atoms of the same elements with a different mass. Each element has a dominant light isotope with the nominal atomic weight (I2C, 160,14N, 32S, and H) and one or two heavy isotopes (l3C, nO, 180, 15N, 33S, 34S, and, 2H) with a natural abundance of a few percent or less Table 1). 

Although the amount of carbon stored in the fossil fuel reservoir is a very small component of the total crustal reservoir, it is large in comparison to the atmospheric reservoir. By burning fossil fuels, we have greatly accelerated the rate at which this carbon is released back into the atmosphere. Once in the atmosphere, this remobilized carbon is then able to interact with the biospheric and hydrospheric reservoirs. 

A further assumption of the model is that liquid, solid, and gas phases are in equilibrium with one another. This assumption demands a relatively rapid and high degree of mixing of atmosphere, lithosphere, and hydrosphere. Under this assumption, the carbon dioxide content of the atmosphere may be considered constant and equal to 3.5 X 10"4 atm. 

Kitano, Y. On factors influencing the polymorphic crystallization of calcium carbonate found in marine biological systems. In Recent researches in the fields of hydrosphere, atmosphere, and nuclear geochemistry. Tokyo, 1964, 305-319. 

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