Organic carbon geological cycle

Figure 10.33. Model of the long-term geological cycle of CO2 (A) and the perturbation to this cycle because of the fossil fuel burning and deforestation activities of humankind (B). ci and c0 are, respectively, inorganic (inorg.) and organic (org.) carbon fluxes. Fluxes are in units of lO 2 moles y1. See text for detailed explanation. (After Wollast and Mackenzie, 1989.)...

The reduction is typically limited by the availability of organic carbon and often occurs in shallow waters at continental margins. Thus, global sulfide production would be dependent on the availability of biological productive areas over geological time. Sulfur-isotope data can be used to constrain simple models of the sulfur cycle over geological time and establish the size of the reservoirs as shown in Figure 5(b). 

Fig. 12.1 Schematic representation of the particulate, organic carbon cycle in the ocean according to Berger et al. (1989). The numerical values have the dimension of gC m yr . Differences between the open ocean and coastal areas are shown. Of the 1% primary production (PP ) that reaches the ocean floor, only 3% are embedded in the open ocean for a period of geological time. In contrast, 97% are decomposed by microbial activity and returned to the water column in the form of dissolved constituents (cf. Fig. 6.6).

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