Nitrogen biogeochemical cycling

General Characterization of Nitrogen Biogeochemical Cycling Processes Let us consider the various ways that N is processed by the biosphere. These ways are important for both terrestrial and oceanic nitrogen cycles. They are shown schematically in Figure 19. 

Thus, the following links of nitrogen biogeochemical cycle were accounted for mass balance calculations in Northern-East Asia and the whole East Asian domain input — deposition, fertilizers, biological N fixation, import of food and products, riverine fluxes and output — crop uptake, denitrification, volatilization, runoff, sedimentation and sea water exchange. All calculations were condncted for 1994-1997 and the mean values were used. 

In contrast, the nature of the surface nitrogen cycle in the Archaean is the subject of debate. Central to this discussion is when the nitrogen biogeochemical cycle began. For example, Mather et al. (2004) have suggested that in the Archaean nitrogen fixation was driven by nonbiological processes and that fixation rates were lower, probably of the order of 1011. However, their model depends upon some assumptions about the extent to which... 

Table 2. Links of nitrogen biogeochemical cycle accounting for N mass balance calculations in East Asia.

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