Source of atmospheric sulfur

Andreae, M. O. (1986). The ocean as a source of atmospheric sulfur compounds. In "The Role of Air-Sea Exchange in Geochemical Cycling" (P. Buat-Menard, ed.). Reidel, Dordrecht. 

Sources of atmospheric sulfur emissions from the process industries are ... 

Sulfonium compounds occur in a wide range of unicellular algae as well as red algae. They have been shown to be the major source of atmospheric sulfur compounds such as dimethyl sulfide and from methanethiol from the ocean, which has a central role ir he global sulfur cycle [143]. 

Summary of Biogenic Sulfur Emissions from the Ocean. To summarize the source fractionation patterns for biogenic sulfur emissions from the oceam a simple isotopic model has been constructed (Figure 1). From this, the S S value of sulfate from a marine biogenic source of atmospheric sulfur can be estimated. 

Non-Marine Sulfur Sources. Non-marine sources of atmospheric sulfur to the remote atmosphere require long distance transport from continental areas. The following section summarizes the isotopic data from anthropogenic, volcanic, and terrestrial biogenic sulfur sources. 

Summary of Non-Marine Sulfur Emissions. S S values for continental sources of atmospheric sulfur dioxide vary, ranging between -32 and +10 0/00. This makes it difficult to use sulfur isotope ratios to distinguish sulfate from these individual sources. It appears that the f S value for marine biogenic sulfur is much more enriched in the heavier isotope than sulfur from continental origins. Therfore, it should be possible to isotopically distinguish between marine biogenic and continentally-derived sulfur. 

Lovelock, Maggs, and Rasmussen (161) have observed the emission of Me2S by microorganisms in the soil and water and suggested that they may provide a large natural source of atmospheric sulfur, particularly in the ocean. 

All the effective SC>2 oxidation reactions mentioned so far are applicable only in polluted environments and are most likely heterogeneous. While these reactions may be important for the global sulfur balance since combustion is a large source of atmospheric sulfur, they are not significant SC oxidation reactions in the normal troposphere. There are, however, a number of homogeneous gas-phase reactions to consider. 

In the last 150 years the anthropogenic emission of sulfur has increased dramatically, primarily due to combustion processes [1]. In the 1950s anthropogenic emission surpassed natural emission and the atmospheric sulfur cycle is one of the most perturbed biogeochemical cycles [1,2]. The oceans are the largest natural source of atmospheric sulfur emissions, where sulfur is emitted in a reduced form, predominantly as dimethyl sulfide (DMS) and to a much lesser extent carbonyl sulfide (OCS) and carbon disulfide (CS2) [3]. Ocean emitted DMS and CS2 are initially oxidised to OCS, which diffuses through the troposphere into the stratosphere where further oxidation to sulfur dioxide (SO2), sulfur trioxide (SO3) and finally sulfuric acid (H2SO4) occurs [1-4]. 

As discussed in Section 2.2, dimethyl sulfide (DMS) emitted from the surface of the oceans is the largest natural source of atmospheric sulfur on a global scale... 

This is a process carried out by Desulfovibrio acting with other bacteria. Because of the presence of sulfate in seawater, this process for the formation of hydrogen sulfide is a significant source of atmospheric sulfur and a source of the pollutant H2S in coastal areas. In areas where this occurs, the sediment is often black in color due to the formation of FeS. In the presence of elemental oxygen, Thiobacillus thiooxidans and other bacteria may oxidize hydrogen sulfide to sulfate ion ... 

Acid rain is best controlled by limiting emissions to the atmosphere of sulfur dioxide and nitrogen oxides, discussed in Sections 8.6 and 8.7. Combustion of coal containing sulfur is a major source of atmospheric sulfur dioxide, the release of which can be limited by stack gas controls, fluidized bed combustion in a sulfur-sequestering medium, and removal of sulfur from coal before combustion... 

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