Biogeochemical cycling The principles

According to the biological cycle, which is that part of the biogeochemical cycle where biomass is produced and decomposed (Fig. 2.22), all volatile compounds occurring in the biochemical cycles can be released to their physical surroundings. These are  

As seen, sulfur and nitrogen also belong in organic compounds. The sulfur and nitrogen cycle is inherent linked with the carbon cycles. As discussed before (Chapter 2.2.2.5), oxygen is closely coupled with the carbon cycle, and is chemically combined with compounds of nitrogen and sulfur (and others). Other cycles, such as those of phosphorous and of trace metals, are important for the biosphere but play a minor role in the atmosphere. With a few exceptions, most of the compounds of these cycles found in the atmosphere are condensed within particulate matter. A 

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. 

With respect to the climate system (biospheric evolution), and in comparison with the man-made activities (noospheric evolution), it is logical to look to natural processes from which substances are released into the atmosphere. Fig. 2.24 shows 

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