Fe-catalyzed sulfide oxidation in hydrothermal plumes is a source of reactive oxygen species to the ocean

Shaw T. J., Luther G. W., Rosas R., Oldham V. E., Coffey N. R., Ferry J. L., ...More

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, vol.118, no.40, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 118 Issue: 40
  • Publication Date: 2021
  • Doi Number: 10.1073/pnas.2026654118
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Animal Behavior Abstracts, Aquatic Science & Fisheries Abstracts (ASFA), Artic & Antarctic Regions, BIOSIS, CAB Abstracts, Chemical Abstracts Core, EconLit, EMBASE, Food Science & Technology Abstracts, INSPEC, Linguistic Bibliography, MathSciNet, MEDLINE, Pollution Abstracts, Psycinfo, Public Affairs Index, Veterinary Science Database, zbMATH, DIALNET
  • Keywords: superoxide, HO, carbon cycle, hydrogen peroxide, sulfide oxidation catalysis, DISSOLVED ORGANIC-CARBON, TRACE HYDROGEN-PEROXIDE, SUPEROXIDE, FE(II), SULFUR, MATTER, FLUIDS, H2O2
  • Middle East Technical University Affiliated: Yes


Historically, the production of reactive oxygen species (ROS) in the ocean has been attributed to photochemical and biochemical reactions. However, hydrothermal vents emit globally significant inventories of reduced Fe and S species that should react rapidly with oxygen in bottom water and serve as a heretofore unmeasured source of ROS. Here, we show that the Fe-catalyzed oxidation of reduced sulfur species in hydrothermal vent plumes in the deep oceans supported the abiotic formation of ROS at concentrations 20 to 100 times higher than the average for photoproduced ROS in surface waters. ROS (measured as hydrogen peroxide) were determined in hydrothermal plumes and seeps during a series of Alvin dives at the North East Pacific Rise. Hydrogen peroxide inventories in emerging plumes were maintained at levels proportional to the oxygen introduced by mixing with bottom water. Fenton chemistry predicts the production of hydroxyl radical under plume conditions through the reaction of hydrogen peroxide with the abundant reduced Fe in hydrothermal plumes. A model of the hydroxyl radical fate under plume conditions supports the role of plume ROS in the alteration of refractory organic molecules in seawater. The ocean's volume circulates through hydrothermal plumes on timescales similar to the age of refractory dissolved organic carbon. Thus, plume-generated ROS can initiate reactions that may affect global ocean carbon inventories.