Cycle of carbon

Biomethanogenesis plays a major role in the cycling of carbon in nature. It has been reported in a broad variety of environments where organic decomposition... 

The cycles of carbon and the other main plant nutrients are coupled in a fundamental way by the involvement of these elements in photosynthetic assimilation and plant growth. Redfield (1934) and several others have shown that there are approximately constant proportions of C, N, S, and P in marine plankton and land plants ("Redfield ratios") see Chapter 10. This implies that the exchange flux of one of these elements between the biota reservoir and the atmosphere - or ocean - must be strongly influenced by the flux of the others. 

Carbon dioxide is likewise an inert material. As a result, its only known sinks are photosynthesis and solubility in seawater. The cycle of carbon dioxide through the atmosphere will be a major focal point in Chapter 11. 

Van Cappellen, P. and Ingall, E. D. (1994). Benthic phosphorus regeneration, net primary production, and ocean anoxia A model of the coupled marine biogeochemical cycles of carbon and phosphoms. Paleoceanography 9,677-692. 

Several interorgan cycles of carbon flow shift the metabolic burden from one tissue type to another. 

Effects of wastewater treatment plant discharge on the ecology of bacterial communities in the sediment of a small, low-gradient stream in South Australia, and the quantification of genes involved in the biogeochemical cycling of carbon and nitrogen [167]... 

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 ... 

Morse, J. W., and F. J. Mackenzie (1990), Geochemistry of Sedimentary Carbonates, Elsevier, Amsterdam. (Comprehensive treatment of carbonate geochemistry, covering the range from electrolyte chemistry of carbon-containing waters to the global cycles of carbon.)... 

As shown in Figure 1, the next step in the catalytic cycle of carbon dioxide hydrogenation is either reductive elimination of formic acid from the transition-metal formate hydride complex or CT-bond metathesis between the transition-metal formate complex and dihydrogen molecule. In this section, we will discuss the reductive elimination process. Activation barriers and reaction energies for different reactions of this type are collected in Table 3. 

Key PEP-CK = PEP carboxykinase this enzyme begins the re-cycling of carbon atoms derived from amino acids (via pyruvate, 2-OG or OAA) or lactate (via pyruvate) to glucose (gluconeogenesis). 

Hayes JM, Strauss H, Kaufman AJ (1999) The abundance of in marine organic matter and isotopic fractionation in the global biogeochemical cycle of carbon during the past 800 Ma. ChemGeol 161 103-125... 

Kump LR (1989) Alternative modeling approaches to the geochemical cycles of carbon, sulfur and strontium isotopes. Am J, Sd 289 390-410 Kump LR (2005) Ironing out biosphere oxidation. Science 307 1058-1059 Kump LR, Arthur MA (1999) Interpreting carbon-isotope excursions carbonates and organic matter, Chem Geol, 161 181-198... 

FIGURE 1 Cycling of carbon dioxide and oxygen between the autotrophic (photosynthetic) and heterotrophic domainsin the biosphere. The flow of massthrough thiscycle isenormous about 4 x 1011 metric tons of carbon are turned over in the bio ihere annually. 

Anabolism and catabolism are complementary to one another, and may be compared with the biologically mediated cycling of carbon (and other materials) in the environment (Fig. 5.2). However, there is an area of metabolism where the two types of metabolism coincide and become indistinguishable. These pathways are known as intermediary metabolism and are the central part of cellular metabolism where the basic requirements for growth are met. At this metabolic crossroads, materials are either rearranged into synthetic precursors or are oxidised to generate energy. 

In many freshwater aquatic systems, dissolved organic material (DOM) represents a major pool of organic material. Processes that produce, consume, and transform DOM are important in the overall cycling of carbon, energy, and nutrients in these aquatic ecosystems. Current research has... 

Mopper, K., and D. J. Kieber. 2002. Impact of DOM photochemistry on the biogeochemical cycling of carbon, nitrogen, sulfur and phosphorus in the sea. In Biogeochemistry of Marine Dissolved Organic Matter (D. Hansell and C. A. Carlson, Eds.), pp. 455-489 Academic Press, New York. 

A. (1995). Belowground cycling of carbon in forests and pastures of Eastern Amazonia. Global Biogeochem. Cycles 9(4), 515-528. 

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