title: Fluids from aging ocean crust that support microbial life.
abstract: Little is known about the potential for life in the vast, low-temperature (<100 degrees C) reservoir of fluids within mid-ocean ridge flank and ocean basin crust. Recently, an overpressured 300-meter-deep borehole was fitted with an experimental seal (CORK) delivering crustal fluids to the sea floor for discrete and large-volume sampling and characterization. Results demonstrate that the 65 degrees C fluids from 3.5-million-year-old ocean crust support microbial growth. Ribosomal RNA gene sequence data indicate the presence of diverse Bacteria and Archaea, including gene clones of varying degrees of relatedness to known nitrate reducers (with ammonia production), thermophilic sulfate reducers, and thermophilic fermentative heterotrophs, all consistent with fluid chemistry.
authors.affiliation: Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI 96822, USA. jcowen@soest.hawaii.edu
authors.forename: James P
authors.initials: JP
authors.lastname: Cowen
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Giovannoni
authors.forename: Fabien
authors.initials: F
authors.lastname: Kenig
authors.forename: H Paul
authors.initials: HP
authors.lastname: Johnson
authors.forename: David
authors.initials: D
authors.lastname: Butterfield
authors.forename: Michael S
authors.initials: MS
authors.lastname: Rappé
authors.forename: Michael
authors.initials: M
authors.lastname: Hutnak
authors.forename: Phyllis
authors.initials: P
authors.lastname: Lam
mesh_terms: D000641:Ammonia / Q000032:analysis / Q000378:metabolism; D001105:Archaea / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D001419:Bacteria / Q000166:cytology / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D018407:Bacterial Physiological Phenomena; D002264:Carboxylic Acids / Q000378:metabolism; D004583:Electrons; D005285:Fermentation; D020459:Genes, rRNA; D019015:Geologic Sediments / Q000382:microbiology*; D006838:Hydrocarbons / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000032:analysis / Q000378:metabolism; D009566:Nitrates / Q000032:analysis / Q000378:metabolism; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D010140:Pacific Ocean; D010802:Phylogeny; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*; D013431:Sulfates / Q000032:analysis / Q000378:metabolism; D013696:Temperature
chemical_list: D002264:Carboxylic Acids; D006838:Hydrocarbons; D009566:Nitrates; D013431:Sulfates; D000641:Ammonia; D006859:Hydrogen; D006862:Hydrogen Sulfide