Nutrient transition metals in a time series of hydrothermal vent fluids from Main Endeavour Field, Juan de Fuca Ridge, Pacific Ocean

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Cabled deep-sea observatories can deliver continuous power and communications linkages to seafloor instruments and sampling devices. Building on this capability, a nine-month time series of hydrothermal vent fluids was recently collected from the well-studied Main Endeavour Field on the Juan de Fuca Ridge (northeast Pacific Ocean) using a novel remotely triggered vent fluid sampling system connected to Ocean Network Canada's NEPTUNE observatory (Seyfried et al., 2022). These samples exhibit very low Mg concentrations (Mg = 0.19–3.07 mmol/kg), indicative of little-to-no contamination by ambient seawater, providing excellent insight into sub-seafloor hydrothermal processes. Here, we present analyses of these samples for transition metals identified as biological nutrients (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, and W) and identify possible controlling processes. Overall, nutrient transition metal concentrations in collected samples reflect dynamic responses to subtle deep-seated and near-surface changes in the hydrothermal system. Roughly two months into the deployment, inmixing of a Mg- and sulfate-rich fluid is decoupled from observed changes in vent fluid temperature but coincides with noticeable decreases in fluid Co and Mo concentrations, likely indicating subtle or more deep-seated cooling of the system and subsurface deposition of these temperature-sensitive metals. Several months later, a ∼20 °C drop in vent fluid temperature from 304 °C to 280–285 °C over ∼20 hours is accompanied by ∼90% decreases in Cu, Zn, and Cd concentrations and an additional decrease in Mo attributable to precipitation of metal sulfides, presumably in the shallow subsurface. Relative stability in concentrations of other metals (V, Cr, Mn, Ni, W) suggests more deeply seated higher-temperature controls, though covariations in Cr and Ni concentrations decoupled from vent fluid temperature suggest subtle, temporally variable lithologic controls. Molybdenum concentrations (29–220 nmol/kg) are higher than expected based on previous analyses of seafloor hydrothermal vent fluids and do not reflect contamination by modern Mo-rich seawater. This finding has implications for understandings of hydrothermal Mo delivery to the ocean, relevant to hypotheses about the evolution of Mo-dependent biological pathways among early life forms in anoxic and Mo-poor ocean environments thought to be prevalent throughout the Archean Eon.

Original languageEnglish (US)
Article number117943
JournalEarth and Planetary Science Letters
Volume602
DOIs
StatePublished - Jan 15 2023

Bibliographical note

Funding Information:
The authors wish to thank the captain and crew of CCGS John P. Tully and pilots of ROV Odysseus for their efforts during deployment and recovery of the sampler and Ocean Networks Canada for building and maintaining the cabled observatory that facilitated this research. Funding for this project was provided by the U.S. National Science Foundation ( EAR 1515377 and OCE 1736679 ) (WES) and the Metal Utilization and Selection across Eons (MUSE) Interdisciplinary Consortium for Astrobiology Research (ICAR) at the University of Wisconsin - Madison , sponsored by the National Aeronautics and Space Administration (NASA) Science Mission Directorate ( 19-ICAR19_2-0007 ), NASA Astrobiology ICAR grant [ 80NSSC21K0592 ] Title: “What life wants: Exploring the natural selection of elements” to Betül Kaçar (PI), WES (Co-I) and GNE. We thank Drew Syverson and an anonymous reviewer for their insightful comments.

Funding Information:
The authors wish to thank the captain and crew of CCGS John P. Tully and pilots of ROV Odysseus for their efforts during deployment and recovery of the sampler and Ocean Networks Canada for building and maintaining the cabled observatory that facilitated this research. Funding for this project was provided by the U.S. National Science Foundation (EAR 1515377 and OCE 1736679) (WES) and the Metal Utilization and Selection across Eons (MUSE) Interdisciplinary Consortium for Astrobiology Research (ICAR) at the University of Wisconsin - Madison, sponsored by the National Aeronautics and Space Administration (NASA) Science Mission Directorate (19-ICAR19_2-0007), NASA Astrobiology ICAR grant [80NSSC21K0592] Title: “What life wants: Exploring the natural selection of elements” to Betül Kaçar (PI), WES (Co-I) and GNE. We thank Drew Syverson and an anonymous reviewer for their insightful comments.

Publisher Copyright:
© 2022

Keywords

  • Ocean Networks Canada
  • Pacific Ocean
  • early life
  • long-term observation
  • seafloor hydrothermal

Fingerprint

Dive into the research topics of 'Nutrient transition metals in a time series of hydrothermal vent fluids from Main Endeavour Field, Juan de Fuca Ridge, Pacific Ocean'. Together they form a unique fingerprint.

Cite this