Global copper cycle

In this final section, the global cycles of two metals, mercury and copper, are reviewed. These metals were chosen because their geochemical cycles have been studied extensively, and their chemical reactions exemplify the full gamut of reactions described earlier. In addition, the chemical forms of the two metals are sufficiently different from one another that they behave differently with respect to dominant... 

Methane is oxidized under aerobic conditions by a group of bacteria called methanotrophs. These widespread bacteria play an important role in the global cycling of methane. Two types of methane oxidation systems are known, a ubiquitous particulate methane monooxygenase (pMMO) and a cytoplasmic soluble methane monooxygenase (sMMO) found in only a few strains. These enzymes have different catalytic characteristics, and so it is important to know the conditions under which each is expressed. In those strains containing both sMMO and pMMO, the available copper concentration controls which enzyme is expressed. However, the activity of the pMMO is also affected by copper. Data on methane oxidation in natural samples suggest that methanotrophs are not copper-limited in nature and express the pMMO predominantly. 

The global cycling of copper has been reviewed by Nriagu (1979) and shown in... 

In this final section, the global cycles of two metals, mercury and copper, are reviewed. These metals... 

The global cycling of copper has been reviewed by Nriagu (1979) and is described schematically in Fig. 15-16. Like most heavy metals and in contrast to mercury, the flux of copper from terrestrial to oceanic reservoirs is dominated by transport in rivers. Copper reaching the oceans by atmospheric transport is of the same order of magnitude as that by three strictly anthropogenic sources direct discharge... 

Fig. 15-18 The global copper cycle. Units are 10 g Cu (burdens) and 10 g Cu/yr (fluxes). (Reprinted with permission from J. O. Nriagu (1979). "Copper in the Environment, Part I Ecological Cycling", Wiley-Interscience, NY.)... 

Nriagu, J.O. 1979c. The global copper cycle. Pages 1-17 in J.O. Nriagu (ed.). Copper in the Environment. Part 1 Ecological Cycling. John Wiley, NY. 

Despite the relatively small part of anthropogenic copper in its global biogeo-chemical cycle, atmospheric transport is responsible for transboundary long range air pollution and impact in many regions of the World, especially in Europe and North America. 

Figure 3. The global copper cycle. The are 10 tons Cu (pools and 10 tons Cit/vear (fluxes) (Benjamin and Honeyman, 1992).

Nriagu, J. 0. (1979). Copper in the Environment, Part I Ecological cycling. New York Wiley-Interscience. Nriagu, J. 0. (1989). A global assessment ofnatural sources of atmospheric trace metals. Nature, vol. 338, 47 9. 

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