Ultra-diffuse hydrothermal venting supports Fe-oxidizing bacteria and massive umber deposition at 5000 m off Hawaii

Katrina J. Edwards, B. T. Glazer, O. J. Rouxel, W. Bach, D. Emerson, R. E. Davis, B. M. Toner, C. S. Chan, B. M. Tebo, H. Staudigel, C. L. Moyer

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


A novel hydrothermal field has been discovered at the base of Lihi Seamount, Hawaii, at 5000 mbsl. Geochemical analyses demonstrate that FeMO Deep, while only 0.2 °C above ambient seawater temperature, derives from a distal, ultra-diffuse hydrothermal source. FeMO Deep is expressed as regional seafloor seepage of gelatinous iron-and silica-rich deposits, pooling between and over basalt pillows, in places over a meter thick. The system is capped by mm to cm thick hydrothermally derived iron-oxyhydroxide-and manganese-oxide- layered crusts. We use molecular analyses (16S rDNA-based) of extant communities combined with fluorescent in situ hybridizations to demonstrate that FeMO Deep deposits contain living iron-oxidizing Zetaproteobacteria related to the recently isolated strain Mariprofundus ferroxydans. Bioenergetic calculations, based on in-situ electrochemical measurements and cell counts, indicate that reactions between iron and oxygen are important in supporting chemosynthesis in the mats, which we infer forms a trophic base of the mat ecosystem. We suggest that the biogenic FeMO Deep hydrothermal deposit represents a modern analog for one class of geological iron deposits known as umbers (for example, Troodos ophilolites, Cyprus) because of striking similarities in size, setting and internal structures.

Original languageEnglish (US)
Pages (from-to)1748-1758
Number of pages11
JournalISME Journal
Issue number11
StatePublished - Nov 2011
Externally publishedYes


  • deep biosphere
  • geomicrobiology
  • hydrothermal
  • iron bacteria
  • iron oxidation

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics


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