Organic carbon distribution

Chemical composition data for CPM and FPM for a variety of locations are summarized in Table 5. These data illustrate several important points. First, the distributions of the PM q between CPM and FPM vary from about 0.4 to 0.7. Second, the ratio of PM q to TSP varies from 0.58 to 0.79. In general, both this ratio and the ratio of FPM to PM q tend to be higher at mral sites, but Bermuda, because of the large influence of sea salt in the CPM, is an exception. Sulfate (SO ), carbon (as organic carbon, OC, and elemental carbon, EC), and nitrate (NO3 ) compounds generally account for 70—80% of the FPM. In the eastern United States, compounds are the dominant species, although very Httie is emitted directiy into the atmosphere. Thus... 

Supports. The principal component of a typical catalyst is the porous support (49,50). Most supports are robust soHds that can be made with wide ranges of surface areas and pore size distributions. The most widely appHed supports are metal oxides others are carbon, kieselguhr, organic polymers, and zeoHtes. 

Fig. 9. Relationship between polarity index ((O + N)/C) and percentage of paraffinic carbon in organic sorbents from the literature. The percentage of paraffinic carbon was calculated as the product of paraffinic carbon content (0-50 ppm) from NMR distribution and percentage of carbon, nitrogen, and oxygen contents from elemental analysis.

Little is known of the oceanic distribution or speciation of cobalt, because very low concentrations (< 200 pM) make its determination difficult. Laboratory studies indicate that cobalt exists in seawater primarily as the cobalt (II) ion and as the carbonate complex. Organic complexes are not considered important. 

Figure 11. Effect of pressure on organic carbon distribution in products and mineral carbonate decomposition...

Wan, J., Tyliszczak, T., and Tokunaga, T. K. (2007). Organic carbon distribution, speciation, and elemental correlation within soil microaggregates Apphcation of STXM and NEXAFS spectroscopy. Geochim. Cosmochim. Acta 71, 5439-5449. 

Kukkonen J, Landrum PF. 1996. Distribution of organic carbon and organic xenobiotics among different particle-size fractions in sediments. Chemosphere 32 1063-1076. 

Destruction of carbonates by organisms also involves translocation of material from the site of biological corrosion or abrasion, and its redistribution in the environment. Carbonate particles which are mechanically removed by gastropods and echinoderms are transported through their digestive tracts and distributed via faecal pellets. Sponges remove the chips of car-... 

Jahnke, R.J. (1996) The global ocean flux of particulate organic carbon distribution and magnitude. Gbbal Biogeochem. Cycles 10, 71-88. 

In eastern Kentucky the Ohio Shale terminology has been used where the Mississippian Sunbury Shale and the underlying Bedford Shale can still be recognized. A typical stratigraphic section with carbon distribution is shown in Figure 3. Typically the overburden is a mixture of claystone and siltstone in the Borden Formation. This unit directly overlies the Sunbury Shale which is a black, laminated, siliceous shale rich in organic matter with some pyrite. The Sunbury thins to the south from 20-25 feet in Lewis County to four feet in Estill County. 

Figure 5. Organic-carbon distribution in Meade Peak (left) and Retort (right) Members of the Phosphoria Formation shown by isograms of average weight percent.

The primitive carbonaceous meteorites, which include the hydrated CI and CM meteorites and mostly-anhydrous meteorites such as the Allende CV meteorite [69], reach Earth from the asteroid belt between Mars and Jupiter. Asteroid reflectance properties display a remarkably systematic distribution as a function of heliocentric distance for asteroids in this belt, and hence meteorite types, with the most primitive ones located farthest from the sun. Asteroid hydration occurred when internal heating melted (water) ice that had co-accreted with dust, chondrules and refractory inclusions in the solar nebula. These asteroids form the IR spectroscopic C-class with clays, carbon and organics at the surface similar to CI and CM meteorite parent bodies [70]. They and the Allende CV parent body, which apparently did not accrete (much) ice, are from the same zone of the asteroid belt. Even more primitive asteroids closer to Jupiter still contain co-accreted ices, organic materials and silicate dust. They define the IR spectroscopic primitive (P)-and dark (D)-class [70] bodies that include comet nuclei and many near-Earth asteroids [10]. 

DYNAMICS OF DISTRIBUTION The natural aqueous system is a complex multiphase system which contains dissolved chemicals as well as suspended solids. The metals present in such a system are likely to distribute themselves between the various components of the solid phase and the liquid phase. Such a distribution may attain (a) a true equilibrium or (b) follow a steady state condition. If an element in a system has attained a true equilibrium, the ratio of element concentrations in two phases (solid/liquid), in principle, must remain unchanged at any given temperature. The mathematical relation of metal concentrations in these two phases is governed by the Nernst distribution law (41) commonly called the partition coefficient (1 ) and is defined as = s) /a(l) where a(s) is the activity of metal ions associated with the solid phase and a( ) is the activity of metal ions associated with the liquid phase (dissolved). This behavior of element is a direct consequence of the dynamics of ionic distribution in a multiphase system. For dilute solution, which generally obeys Raoult s law (41) activity (a) of a metal ion can be substituted by its concentration, (c) moles L l or moles Kg i. This ratio (Kd) serves as a comparison for relative affinity of metal ions for various components-exchangeable, carbonate, oxide, organic-of the solid phase. Chemical potential which is a function of several variables controls the numerical values of Kd (41). 

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