Biosphere and atmosphere

On a global scale, most of the S is located in the lithosphere however, there are important interactions between the hydrosphere, biosphere, and atmosphere where important transfers of S occur. 

The list of S species, which are important for exchange between biosphere and atmosphere, includes also carbonyl sulfide (COS), carbon disulfide (CS2) and various methylated species (methanethiol, dimethyl sulfide and dimethyl disulfide). Dimethyl sulfide (DMS) dominates biogenic S emission from marine and fresh water ecosystems. 

Fig. 11-7. Exchange of atmospheric C02 with the terrestrial biosphere. Left (solid line) Seasonal variation of atmospheric C02 at two stations (northern and southern hemisphere) compared with (dashed line) model calculations by Pearman and Hyson (1981). Center Rate of C02 exchange between biosphere and atmosphere for three latitude bands in the northern hemisphere derived from a best lit of the model to observational data. Right Integrated annual C02 net exchange rate versus latitude.

A very small part of the photosynthetic net production is buried in sediments, isolated from the oxygen of the atmosphere and thus sequestered from the rapid atmual carbon turnover between biosphere and atmosphere. Under favorable... 

As mentioned already, the CO2 cycle has one major problem in the atmosphere -there is no direct chemical sink. In nature, CO2 can only be assimilated by plants (biological sink) through conversion into hydrocarbons (Chapter 2.2.2.3) and stored in calcareous organisms, partly buried in sediments but almost completely turned back into CO2 by respiration hence, CO2 partitions between the biosphere and atmosphere. With respect to time periods being of interest for humankind (from decades to hundreds of years) this natural biogeoehemical recycling can be regarded to be closed or, in other words, the net flux is zero ... 

Indexes + and - denote sources and sinks relative to the atmosphere. Hence, all concentrations (pools) in the biosphere and atmosphere remain constant (we should... 

Andreae, M. O. (1991) Biomass burning Its history, use, and distribution and its impact on environmental quality and global climate. In Levine (1991) pp. 3-27 Andreae, M. O. and W. Jaeschke (1992) Exchange of sulphur between biosphere and atmosphere over temperate and tropical regions. In Sulphur cycling on the continents (Eds. R. W. Howarth, J. W. B. Stewart and M. V. Ivanov). John WUey Sons, New York, pp. 27-61 Andreae, M. O. (1995) Climatic effects of changing atmospheric aerosol levels. In World survey of climatology. Vol. 16 Future climates of the world (Ed. A. Henderson-Sellers). Elsevier, Amsterdam, pp. 341-392... 

Coal combustion releases substantial quantities of carbon dioxide (CO2) to the atmosphere that can participate in one or more of the various cycles that exist in the biosphere and atmosphere (Clark, 1989 Graedel and Crutzen, 1989 Frosch and Gallopoulos, 1989 Maurits la Rivibre, 1989 Schneider, 1989 Speight and Lee, 2000) have dominated the global environmental system for millennia. In addition, other coal plant emissions such as sulfur dioxide (SO2) and nitrogen oxides (NO) are major contributors to acid rain (Manowitz and Lipfert, 1990). 

Andreae MO, Jaeschke WA. Exchange of sulfur between biosphere and atmosphere over temperate and tropical regions. In Horwarth RW, Stewart JWB, Ivanov MV, eds. Sulfur Cycling on the Continents. Chichester Wiley 1992 27-61. 

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