Global geochemical models

Baross JA. 1998. Do the geological and geochemical records of the early Earth support the prediction from global phylogenetic models of a thermophilic ancestor In Wiegel J, Adams M, editors. Thermophiles the keys to molecular evolution and the origin of life London Taylor Francis, pp. 13-18. 

In the seventies, the growing interest in global geochemical cycles and in the fate of man-made pollutants in the environment triggered numerous studies of air-water exchange in natural systems, especially between the ocean and the atmosphere. In micrometeorology the study of heat and momentum transfer at water surfaces led to the development of detailed models of the structure of turbulence and momentum transfer close to the interface. The best-known outcome of these efforts, Deacon s (1977) boundary layer model, is similar to Whitman s film model. Yet, Deacon replaced the step-like drop in diffusivity (see Fig. 19.8a) by a continuous profile as shown in Fig. 19.8 b. As a result the transfer velocity loses the simple form of Eq. 19-4. Since the turbulence structure close to the interface also depends on the viscosity of the fluid, the model becomes more complex but also more powerful (see below). 

This approach requires geochemical models to quantify and test hypothesized relationships among global fluxes and reservoirs. 

The first and most important step in the modelling of chemical reactions is to decide whether they are controlled by chemical thermodynamics or kinetics, or possibly by a combination of the two. This also applies to the modelling of more complex chemical systems and processes, such as waste repositories of various kinds, the processes describing transport of toxic materials in ground and surface water systems, the global geochemical cycles, etc. 

Hudson R. J. M. et al. (1994). Modeling the global carbon cycle Nitrogen fertilization of the terrestrial biosphere and the "missing" CO2 sink. Global Bio-geochem. Cycles 8, 307-333. 

Hein R, Crutzen PJ, Heimann M. 1997. An inverse modeling approach to investigate the global atmospheric methane cycle. Global Bio geochemical Cycles 11 43-76. 

Maier-Reimer, E. (1993). Geochemical cycles in an ocean general circulation model - Preindustrial tracer distributions. Global Biogeochem. Cycles 7, 645—677. 

Lefevre N. and Watson A. (1999) Modeling the geochemical cycle of iron in the oceans and its impact on atmospheric CO, concentrations. Global Biogeochem. Cycles 13, 727-736. 

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