Sulphur isotopic investigation of dissolved and solid sulphur phases in fluids, mineral precipitates, sediments and rock samples from the Mid-Atlantic Ridge

该研究项目的最终目标是从质和量上了解洋中脊的硫循环。从两个主要研究地点（即洛加切夫热液区和南部MAR地点）的液体和固体样品中获得的不同硫形式的元素和同位素结果为各种硫化合物（包括亚稳硫醇）的无机（地幔硫的沥滤和高温海水硫酸盐还原）和生物（硫酸盐和元素硫的还原）循环提供了证据。目前的估计，部分是基于大量的多种硫同位素数据，指出再循环海水硫酸盐对热液流体的总硫预算的贡献为30%。未来的工作将集中在两个不同的方面：（a）以不同的空间分辨率确定多种硫同位素，以便（i）量化不同的硫贡献（即再循环海水硫酸盐、沥滤地幔硫、生物硫循环，以及（ii）查明大洋中脊热液环境中硫同位素分馏的详细情况，和（B）根据从所研究的喷口地点培养的生物的培养实验，对硫代谢和相关的同位素效应进行量化。

The ultimate objective of this research project is a qualitative and quantitative understandingof sulphur cycling at mid-ocean ridges. Abundance and isotope results obtained so far fordifferent sulphur forms in liquid and solid samples from the two principal study sites (i.e.Logatchev hydrothermal field and southern MAR sites) provide evidence for inorganic(leaching of mantle sulphur and high-temperature seawater sulphate reduction) andbiological (reduction of sulphate and elemental sulphur) cycling of a diverse mix of sulphurcompounds, including metastable thiols. Current estimates, in part based on preliminarymultiple sulphur isotope data, point to a 30% contribution from recycled seawater sulphate tothe overall sulphur budget of hydrothermal fluids.Future work will focus on two different aspects: (a) the determination of multiple sulphurisotopes at different spatial resolutions in order to (i) quantify the different sulphurcontributions (i.e. recycled seawater sulphate, leached mantle sulphur, biological sulphurcycling, and (ii) identify the details of sulphur isotope fractionation at mid-ocean ridgehydrothermal settings, and (b) the quantification of sulphur metabolism and associatedisotope effects based on culture experiments with organisms cultivated from the vent sitesstudied.