Global Fluxes and Pools of Sulfur

We can presume that there are three major reasons which specify the biogeochemical cycle of sulfur  

Microbial transformation of sulfur gases play an important role in S exchange between atmosphere and biosphere  

Sulfurous gases transform easily to readily soluble sulfates, which are a predominate form of riverine S migration  

Formation of hydrogen sulfide in wetlands leads to the reactions between H2S and soluble metals, especially iron, with subsequent deposition of insoluble metal sulfides. 

These reasons are connected with S biogeochemical fluxes and pools in biosphere, atmosphere and hydrosphere. However, the main reservoirs are related to lithosphere. According to Ronov (1976) and Dobrovolsky (1994), the average concentration of sulfide sulfur in sedimentary shell is 0.183% and the total amount of sulfur is 9.3 x 10 tons. In addition, the granite crustal layer contains 8.6 x 10 - tons of S. Totally in the Earth s crust there is around 94% of the global S mass (Table 24). 

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