Carbon release

Chemical weathering of crustal material can both add and withdraw carbon from the atmosphere. This has been discussed in Chapter 8. The oxidation of reduced carbon releases CO2 to the atmosphere,... 

Gross differences have been ob.served in the amounts of fixed carbon released by annuals and perennials (47), with annuals releasing much less C than perennials. This effect may in part be due to perennials having to invest more of their assimilates to survive year round. Between more closely related plants, several studies have reported that both the quantity and quality of root exudates vary between plant species (39,48,49). In addition, it is also recognized that different cultivars of the same species may vary in their root exudation patterns. For example, Cieslinski et al. (50) quantified low-molecular-weight organic acids released... 

Carbon is a true pharmakom a poison and a gift, powering the modern world. Carbon released into the atmosphere mere years or decades ago is now being taken up by plants. But fossil carbon taken from the earth accumulated over millions of years. Carbon, then, is a temporal problem, and thus it is intimately linked with the nexus of alchemy and mining. 

When the gas reaction takes place truly inside the solid, the mode of access of the gas is most relevant. Thus, the carbiding of solid iron by a hydrocarbon gas is effected by dissolved carbon released at the iron surface by the decomposition of the hydrocarbon... 

Improvement of rates is mainly the result of biocatalyst engineering, while improvement of yields result from the biocatalyst selectivity and from mass transport between phases. This last phenomenon is also a key feature for environmental aspects. Hence, most of the impacts of a biological process deal with carbon release in the environment. This release takes place in the form of VOCs, including CO2. If it is difficult to avoid CO2 production when microorganisms are involved (it is still the same with enzymes because they were preliminary produced by cell cultivation), care can be taken for other organic compounds. 

Some of the carbon released by decomposition may be washed into rivers and the ocean. Some of it may be taken up by other living things for use in their life processes. Some of it maybe buried in sediments and, over long periods of time, converted to fossil fuels. The burial and conversion of carbon compounds to fossil fuels upsets the balance between photosynthesis and respiration because these processes remove the carbon from the cycle for such long periods of time. Some carbon is also removed from the cycle for longs periods of time when the shells of some small ocean-dwelling... 

Source Agriculture, industrial processes. Specifically, industrial plants for the production of pulp from timber or other fibrous materials, and paper or board production are responsible of 70% of the total organic carbon released directly into water from industry per year. 

FIGURE 16-7 Reactions of the citric acid cycle. The carbon atoms shaded in pink are those derived from the acetate of acetyl-CoA in the first turn of the cycle these are not the carbons released as CO2 in the first turn. Note that in succinate and fumarate, the two-carbon group derived from acetate can no longer be specifically denoted because succinate and fumarate are symmetric molecules, C-l and C-2 are indistinguishable from C-4 and C-3. The number beside each... 

FIGURE 21-3 The overall process of palmitate synthesis. The fatty acyl chain grows by two-carbon units donated by activated malonate, with loss of C02 at each step. The initial acetyl group is shaded yellow, C-l and C-2 of malonate are shaded pink, and the carbon released as C02 is shaded green. After each two-carbon addition, reductions convert the growing chain to a saturated fatty acid of four, then six, then eight carbons, and so on. The final product is palmitate (16 0). 

Page SE, Siegert F, Rieley JO, Boehm H-DV, Jaya A, Limin S (2002) The Amount of Carbon Released from Peatland Forest Fires in Indonesia During 1997. Nature 420 61... 

Sundh, I. 1991. The dissolved organic carbon released from lake phytoplankton — biochemical composition and bacterial utilization. Ph.D. Dissertation, Uppsala University, Sweden,... 

Wiebe, W. J., and D. F. Smith. 1977. Direct measurement of dissolved organic carbon release by phytoplankton and incorporation by microheterotrophs. Marine Biology 42 213—223. 

Hygum, B. H., J. W. Petersen, and M. Sondergaard. 1997. Dissolved organic carbon released by zooplankton grazing activity — A high-quality substrate pool for bacteria. Journal of Plankton Research 19 97-111. 

Figure 4.2. Carbon released as C02 from unamended soil and soils amended with pig slurry (PS), poultry manure (PM), cattle farmyard manure (FYM), aerobic sewage sludge (SS), municipal solid waste fuse compost (RC), and rye straw (RS) at a rate of lOgkg1 during incubation at 22 °C. Reprinted from Levi-Minzi, R., Riffaldi, R., and Saviozzi, A. (1990). Carbon mineralization in soil amended with different organic materials. Agric. Ecosyst. Environ. 31, 325-335, with permission from Elsevier.

Dutta, K., Schuur, E. A. G., Neff, J. C., and Zimov, S. A. (2006). Potential carbon release from permafrost soils of Northeastern Siberia. Global Change Biol. 12(12), 2336-2351. 

Notes Sodium carbonate releases a gas when added to an acid stop bath or an acid fixing bath this gas may cause pinholes, or blistering, to develop in film emulsions. 

Reactions of metal oxides with elementary carbon or sulfur produce the carbides and sulfides. The reaction of FeTi03 with carbon releases Fe and TiC, and the reaction with CaW04 produces Ca and WC. These hard materials are used for mechanical purposes [70]. 

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