Multiple sulphur and oxygen isotopes reveal microbial sulphur cycling in spring waters in the Lower Engadin, Switzerland.
Highly mineralized springs in the Scuol-Tarasp area of the Lower Engadin and in the Albula Valley near Alvaneu, Switzerland, display distinct differences with respect to the source and fate of their dissolved sulphur species. High sulphate concentrations and positive sulphur (δ(34)S) and oxygen (δ(18)O) isotopic compositions argue for the subsurface dissolution of Mesozoic evaporitic sulphate. In contrast, low sulphate concentrations and less positive or even negative δ(34)S and δ(18)O values indicate a substantial contribution of sulphate sulphur from the oxidation of sulphides in the crystalline basement rocks or the Jurassic sedimentary cover rocks. Furthermore, multiple sulphur (δ(34)S, Δ(33)S) isotopes support the identification of microbial sulphate reduction and sulphide oxidation in the subsurface, the latter is also evident through the presence of thick aggregates of sulphide-oxidizing Thiothrix bacteria.
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.
Harald
H
Strauss
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.|b Limnology Department , Uppsala University , Uppsala , Sweden.
Hannah
H
Chmiel
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.
Andreas
A
Christ
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.
Artur
A
Fugmann
c Department of Earth Sciences, Geomicrobiology Group , ETHZ , Zürich , Switzerland.
Kurt
K
Hanselmann
d Geomicrobiology, Center for Applied Geosciences , University of Tuebingen , Tuebingen , Germany.
Andreas
A
Kappler
e Bundesanstalt für Geowissenschaften und Rohstoffe , Hannover , Germany.
Paul
P
Königer
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.
Andreas
A
Lutter
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.
Katharina
K
Siedenberg
a Institut für Geologie und Paläontologie , Westfälische Wilhelms-Universität Münster , Münster , Germany.
Barbara M A
BM
Teichert
D019015:Geologic Sediments / Q000737:chemistry; D008900:Mineral Waters / Q000032:analysis* / Q000382:microbiology; D060985:Natural Springs / Q000737:chemistry* / Q000382:microbiology; D010103:Oxygen Isotopes / Q000032:analysis; D013431:Sulfates / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*; D013460:Sulfur Isotopes / Q000032:analysis; D013557:Switzerland; D053525:Thiothrix / Q000378:metabolism*
D008900:Mineral Waters; D010103:Oxygen Isotopes; D013431:Sulfates; D013460:Sulfur Isotopes; D013455:Sulfur
hydrogen-2; isotope geochemistry; microbial sulphur cycling; oxygen-18; spring water; sulphate reduction; sulphur-33; sulphur-34; sulphur-36