Anthropogenic flux

Table 11.2 Comparison of Natural and Anthropogenic Fluxes of Heavy Metals Circa 1983 and 1995. 

POL A simulation model of the formation of anthropogenic fluxes of pollutants. 

In the second case (Figure 10.34B), the excess carbon is stored in the ocean, either in the water column or in sediments, and the CO2 evasion flux is maintained at the geologic rate. In this case, the oceanic reservoir gains 59.2 x 1012 moles C y1, an increase in storage capacity of 11% of the anthropogenic flux of carbon to the atmosphere. Much of this increase takes place in the nearshore realm, although potential transport of DOC, POC, and DIC to the open ocean would also increase the loading of this part of the ocean. 

For the purpose of this chapter, we will first examine how human activities affect these fluxes, estimating the relative importance of the various anthropogenic fluxes of equation (2) for Brazilian Amazonia the landscape unit for our estimates is therefore the entire original forested region (Table 8.2). Then, we will demonstrate how extractive reserves and extractivist activities are related to these broader anthropogenical-ly induced fluxes. 

The relative magnitudes of the fluxes described in equation (2) can be compared graphically in Fig. 8.1. Although the erosion flux may be important on a local basis, it probably represents more a redistribution of carbon between the terrestrial and fluvial systems than a flux to the atmosphere. The dominant gas flux is from deforestation. Consequently, land uses that maintain forest cover and/or reduce the deforestation rate will have a major impact on the anthropogenic fluxes, thereby affecting the total... 

Table 8 Estimates of relative importance of the various anthropogenic fluxes of equation (2) for Brazilian Amazonia.

Selenium is dispersed through the environment and is cycled by biogeochemical processes involving the rock weathering, rock-water interactions, and microbiological activity. Estimates of the selenium fluxes through the atmosphere, land, and oceans indicate that the anthropogenic flux now exceeds the marine flux, the principal natural pathway (Table 10). 

Ultimately, research in the halogen cycles and the interface between natural and anthropogenic fluxes is directed towards risk quantification and reduction, through research questions such as Do environmental transformation reactions... 

Uchvatov, V. P. (1994). Natural and anthropogenic fluxes of substances in the landscapes of the Russian plain. Dr. Sci. Thesis. Pushchino, 471 pp. 

Emissions of sulfur to the atmosphere by humans are almost entirely in the form of SO2. The main sources are coal-burning and sulfide ore smelting. The total anthropogenic flux is estimated to be about 80TgS/year (Ivanov, 1983) and is thus essentially equal in magnitude to the natural flux of low oxidation state sulfur to the atmosphere. Clearly, the atmospheric sulfur cycle is intensely perturbed by human activity. To estimate the spatial extent of this perturbation, we will need some idea of the residence time of sulfur in the atmosphere. 

Element Anthropogenic flux (ug/cm year) Natural flux year)... 

Table 1 Fluxes of metals to the atmosphere from natural and anthropogenic sources. The interference factor is the ratio of the anthropogenic flux to the natural flux. The generic term combustion refers to various combinations of coal, oil, and wood combustion and refuse incineration...

It is essential to know better the natural fluxes (anthropogenic fluxes are rather well estimated) and their variations, but even more important is knowledge about the biosphere-atmosphere interaction What processes control the environmental parameters that themselves maintain life on earth We can then ask another question What is the threshold of quantitative change (of any parameter) leading to a new quality of life Finally, we have to answer (or to define) what changes in air, soil and water quality humankind can even accept in future against the background of sustainable development. 

Emissions of various kinds of gases caused by human activities (burning of fossil fuels, production of concrete, smelting etc.) occur. It is obvious that anthropogenic fluxes exceed natural fluxes for many elements (Table 6.1). 

Table 6.1 shows fluxes for metals from mines, emission to atmosphere, transportation by rivers, and removal by rainwater. Most of anthropogenic metals transported to atmosphere are taken up by rainwater. However, this is unclear because fluxes to the atmosphere are not only by human activity but also by namral process such as volcanic activity and estimated proportion of these two processes has large uncertainty. Riverine fluxes to ocean are mostly larger than anthropogenic fluxes to atmosphere and fluxes by rainwater, but anthropogenic fluxes to atmosphere for toxic metals (Pb, Hg, Se, As, and Sb) are considerably large. 

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