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Dissolved species like sulfate and nitrate contain differing ratios of 34-S to 32-S or 15-N to 14-N, and are often diagnostic of pollutant sources. Natural radioisotopes like tritium (3-H) and radiocarbon ( 14-C ) are also used as natural clocks to determine the residence times of water in aquifers, rivers, and the oceans.
The important sulfur cycle is a biogeochemical cycle in which the sulfur moves between rocks, waterways and living systems. It is important in geology as it affects many minerals and in life because sulfur is an essential element (), being a constituent of many proteins and cofactors, and sulfur compounds can be used as oxidants or reductants in microbial respiration. [1]
The presence of sulfate-reducing bacteria, which reduce sulfate (SO 2− 4) to hydrogen sulfide (H 2 S), has played a significant role in the oceanic δ 34 S value throughout the earth's history. Sulfate-reducing bacteria metabolize 32 S more readily than 34 S, resulting in an increase in the value of the δ 34 S in the remaining sulfate in the ...
Microbial sulfate reduction has been demonstrated to fractionate sulfur isotopes in bacteria, with some studies showing a dependence upon sulfate concentration [28] and/or temperature. [64] Studies examining dozens of species of dissimilatory sulfate reducing microbes have observed sulfur isotope fractionations ranging from −65.6‰ to 0‰.
The uptake of sulfate by the roots and its transport to the shoot is strictly controlled and it appears to be one of the primary regulatory sites of sulfur assimilation. [3] Sulfate is actively taken up across the plasma membrane of the root cells, subsequently loaded into the xylem vessels and transported to the shoot by the transpiration stream.
Radium sulfate is the most insoluble sulfate known. The barium derivative is useful in the gravimetric analysis of sulfate: if one adds a solution of most barium salts, for instance barium chloride, to a solution containing sulfate ions, barium sulfate will precipitate out of solution as a whitish powder. This is a common laboratory test to ...
The resulting sulfate ions are precipitated (often by mixture with barium chloride to produce barium sulfate), and the solid sulfate precipitate is filtered, dried, and transferred to an elemental analysis pipeline, which may involve the combustion of the sample and the mass balance of its various combustion products (which should include CO 2 ...
The sulfur cycle. Under anaerobic conditions, sulfate is reduced to sulfide by sulfate reducing bacteria, such as Desulfovibrio and Desulfobacter. SO 2− 4 + 4H 2 → H 2 S + 2H 2 O + 2OH −. Sulfide Oxidation. Under aerobic conditions, sulfide is oxidized to sulfur and then sulfate by sulfur oxidizing bacteria, such as Thiobacillus ...