Isotope exchange reactions with radiolabeled sulfur compounds in anoxic seawater

摘要: The isotope exchange between35S-labeled sulfur compounds of sulfate (SO4 2−), elemental (S0), polysulfide (Sn 2−), hydrogen sulfide (ΣHS−: H2S + HS− S2−), iron (FeS), and pyrite (FeS2) was studied at pH 7.6 20 °C in anoxic, sterile seawater. Isotope observed between S0, S2 2− ΣHS−, FeS, but not between35S labeled SO4 2− or FeS2 the other compounds. Polysulfide mediated S0 bisulfide (HS−). Sn 2−) reached 50% equilibrium within < 2 min while approached 0.5-1 h. In all experiments revealed a fraction from 0.79 to 1.00. S2− FeS took place only via and/or HS−. complete 24 h as shown by 0.07–0.83. This lack (fraction 1) due dissolved surfaces particles. isotopic reactions limit usefulness radiotracers process studies inorganic species. Exchange will also affect stable distribution among kinetics reactions, however, depend on both temperature.