FN Archimer Export Format
PT J
TI Iron Transformation Pathways and Redox Micro-Environments in Seafloor Sulfide-Mineral Deposits: Spatially Resolved Fe XAS and delta Fe-57/54 Observations
BT 
AF TONER, Brandy M.
   ROUXEL, Olivier
   SANTELLI, Cara M.
   BACH, Wolfgang
   EDWARDS, Katrina J.
AS 1:1;2:2;3:3;4:4,5;5:6;
FF 1:;2:PDG-REM-GM-LCG;3:;4:;5:;
C1 Univ Minnesota Twin Cities, Dept Ressources Phys & Ecosyst Fond Mer Water &, St Paul, MN USA.
   IFREMER, Ctr Brest, Dept Deep Sea Phys Resources & Ecosyst, Plouzane, France.
   Univ Minnesota Twin Cities, Dept Earth Sci, Minneapolis, MN USA.
   Univ Bremen, Dept Geosci, D-28359 Bremen, Germany.
   Univ Bremen, MARUM, D-28359 Bremen, Germany.
   Univ Calif Los Angeles, Dept Biol Sci, Los Angeles, CA USA.
C2 UNIV MINNESOTA, USA
   IFREMER, FRANCE
   UNIV MINNESOTA, USA
   UNIV BREMEN, GERMANY
   UNIV BREMEN MARUM, GERMANY
   UNIV CALIF LOS ANGELES, USA
SI BREST
SE PDG-REM-GM-LCG
IN WOS Ifremer jusqu'en 2018
   DOAJ
   copubli-europe
   copubli-int-hors-europe
IF 4.076
TC 18
UR https://archimer.ifremer.fr/doc/00337/44810/44375.pdf
LA English
DT Article
DE ;hydrothermal;East Pacific Rise;X-ray absorption spectroscopy;stable isotopes;micro-environment;mineral alteration;iron;biosignature
AB Hydrothermal sulfide chimneys located along the global system of oceanic spreading centers are habitats for microbial life during active venting. Hydrothermally extinct, or inactive, sulfide deposits also host microbial communities at globally distributed sites. The main goal of this study is to describe Fe transformation pathways, through precipitation and oxidation-reduction (redox) reactions, and examine transformation products for signatures of biological activity using Fe mineralogy and stable isotope approaches. The study includes active and inactive sulfides from the East Pacific Rise 9 degrees 50'N vent field. First, the mineralogy of Fe(III)-bearing precipitates is investigated using microprobe X-ray absorption spectroscopy (RXAS) and X-ray diffraction (mu XRD). Second, laser-ablation (LA) and micro-drilling (MD) are used to obtain spatially-resolved Fe stable isotope analysis by multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS). Eight Fe -bearing minerals representing three mineralogical classes are present in the samples: oxyhydroxides, secondary phyllosilicates, and sulfides. For Fe oxyhydroxides within chimney walls and layers of Si-rich material, enrichments in both heavy and light Fe isotopes relative to pyrite are observed, yielding a range of delta Fe-57 values up to 6 parts per thousand. Overall, several pathways for Fe transformation are observed. Pathway 1 is characterized by precipitation of primary sulfide minerals from Fe(II)aq-rich fluids in zones of mixing between vent fluids and seawater. Pathway 2 is also consistent with zones of mixing but involves precipitation of sulfide minerals from Fe(II)aq generated by Fe(III) reduction. Pathway 3 is direct oxidation of Fe(II) aq from hydrothermal fluids to form Fe(III) precipitates. Finally, Pathway 4 involves oxidative alteration of pre-existing sulfide minerals to form Fe(III). The Fe mineralogy and isotope data do not support or refute a unique biological role in sulfide alteration. The findings reveal a dynamic range of Fe transformation pathways consistent with a continuum of micro-environments having variable redox conditions. These micro-environments likely support redox cycling of Fe and S and are consistent with culture-dependent and -independent assessments of microbial physiology and genetic diversity of hydrothermal sulfide deposits.
PY 2016
PD MAY
SO Frontiers In Microbiology
SN 1664-302X
PU Frontiers Media Sa
VL 7
IS 648
UT 000375404800001
DI 10.3389/fmicb.2016.00648
ID 44810
ER

EF