Bacterial methane oxidation in sea-floor gas hydrate; significance to life in extreme environments

Samples of thermogenic hydrocarbon gases, from vents and gas hydrate mounds within a sea-floor chemosynthetic community on the Gulf of Mexico continental slope at about 540 m depth, were collected by research submersible. Our study area is characterized by low water temperature (mean = 7°C), high pr...

Full description

Saved in:
Bibliographic Details
Published in:Geology (Boulder) 1998-09, Vol.26 (9), p.851-854
Main Authors: Sassen, Roger, MacDonald, Ian R, Guinasso, Jr, Joye, Samantha, Requejo, Adolfo G, Sweet, Stephen T, Alcalá Herrera, Javier A, DeFreitas, Debra A, Schink, David R
Format: Article
Language:English
Subjects:
aliphatic hydrocarbons
alkanes
Atlantic Ocean
authigenesis
Bacteria
biogenic processes
Bivalvia
Bush Hill
C-13/C-12
carbon
carbonate rocks
chemosynthesis
communities
continental slope
D/H
deep-sea environment
deuterium
ecology
Environmental geology
Garden Banks
gas hydrates
geochemistry
Green Canyon
Gulf of Mexico
hemipelagic environment
high pressure
hydrocarbons
hydrogen
hydrothermal vents
Invertebrata
isotope ratios
isotopes
Jolliet Field
Louisiana
low temperature
Marine
marine environment
marine sediments
Methane
Mollusca
mounds
North Atlantic
Oceanography
Oceans
oil and gas fields
organic compounds
Oxidation
pressure
sedimentary rocks
sediments
stable isotopes
temperature
Texas
United States
Vermes
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Samples of thermogenic hydrocarbon gases, from vents and gas hydrate mounds within a sea-floor chemosynthetic community on the Gulf of Mexico continental slope at about 540 m depth, were collected by research submersible. Our study area is characterized by low water temperature (mean = 7°C), high pressure (about 5400 kPa), and abundant structure II gas hydrate. Bacterial oxidation of hydrate-bound methane (CH4) is indicated by three isotopic properties of gas hydrate samples. Relative to the vent gas from which the gas hydrate formed, (1) methane-bound methane is enriched in 13C by as much as 3.8 per mil PDB (Peedee belemnite), (2) hydrate-bound methane is enriched in deuterium (D) by as much as 37 per mil SMOW (standard mean ocean water), and (3) hydrate-bound carbon dioxide (CO2) is depleted in 13C by as much as 22.4 per mil PDB. Hydrate-associated authigenic carbonate rock is also depleted in 13C. Bacterial oxidation of methane is a driving force in chemosynthetic communities, and in the concomitant precipitation of authigenic carbonate rock that modifies sea-floor geology. Bacterial oxidation of hydrate-bound methane expands the potential boundaries of life in extreme environments.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(1998)026<0851:BMOISF>2.3.CO;2