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Properties and Dispersal of a Hydrothermal Plume in a Weakly Stratified Under-Ice Environment
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  • Maren Walter,
  • Andreas Türke,
  • Alexander Diehl,
  • Christopher R German,
  • Christian Mertens,
  • Jonathan Mette,
  • Patrick Monien,
  • Simon Prause,
  • Jürgen Sültenfuß,
  • Wolfgang Bach,
  • Vera Schlindwein,
  • Antje Boetius
Maren Walter
University of Bremen

Corresponding Author:[email protected]

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Andreas Türke
Universitat Bremen
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Alexander Diehl
University of Bremen
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Christopher R German
Wood Hole Oceanographic Institution
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Christian Mertens
University of Bremen
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Jonathan Mette
Universitat Bremen
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Patrick Monien
University of Bremen
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Simon Prause
Universitat Bremen
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Jürgen Sültenfuß
University of Bremen
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Wolfgang Bach
University of Bremen
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Vera Schlindwein
Alfred-Wegener-Institut Helmholtz-Zentrum fur Polar- und Meeresforschung
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Antje Boetius
Alfred Wegener Institut
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Abstract

The Aurora vent field (82°53.83’ N, 6°15.32’ W) is located in the weakly stratified Arctic Ocean under perennial ice cover at the western edge of the ultraslow-spreading Gakkel Ridge, the slowest spreading mid-ocean ridge on Earth. Here, we report data on the dispersal of the proximal hydrothermal plume in this extreme environment. The hydrothermal plume is of unusual dimensions, with a small horizontal, but large vertical extent, which is caused by the hydrography of the Arctic Ocean. Water column parameters such as turbidity and redox potential show a highly variable but horizontally confined non-buoyant plume. Dissolved iron (dFe), manganese (dMn), δ3He, and methane (CH4) all show distinct enrichments in the hydrothermal plume relative to background deep-water, but relatively low peak concentrations due to the dilution over a vertical extent of over 500 m. Plume particle samples exhibit elevated Fe/Al ratios consistent with Fe-oxyhydroxide precipitation close to the vent, whereas particulate Mn/Al ratios do not reveal any complementary pMn enrichments in the proximal plume. Positive correlation between Fe/Al, and several other element/Al ratios (e.g. P, V, As) are consistent with scavenging of these elements onto Fe-hydroxide plume particles and removal into the underlying sediments. Surface sediment samples collected close to Aurora reveal highly elevated concentrations of hydrothermally-sourced elements in the immediate vicinity of the vent-site. For example, proximal surface sediments contained up to 8222 mg kg-1 Cu, whereas Cu concentrations in core tops a few kilometers away from the site were much lower (<50 mg kg-1).
31 Oct 2024Submitted to ESS Open Archive
01 Nov 2024Published in ESS Open Archive