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Bacteria and Archaea Physically Associated with Gulf of Mexico Gas Hydrates

Lanoil, Brian D. and Sassen, Roger and La Duc, Myron T. and Sweet, Stephen T. and Nealson, Kenneth H. (2001) Bacteria and Archaea Physically Associated with Gulf of Mexico Gas Hydrates. Applied and Environmental Microbiology, 67 (11). pp. 5143-5153. ISSN 0099-2240. PMCID PMC93283. https://resolver.caltech.edu/CaltechAUTHORS:LANaem01

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Abstract

Although there is significant interest in the potential interactions of microbes with gas hydrate, no direct physical association between them has been demonstrated. We examined several intact samples of naturally occurring gas hydrate from the Gulf of Mexico for evidence of microbes. All samples were collected from anaerobic hemipelagic mud within the gas hydrate stability zone, at water depths in the ca. 540- to 2,000-m range. The delta 13C of hydrate-bound methane varied from -45.1per thousand Peedee belemnite (PDB) to -74.7per thousand PDB, reflecting different gas origins. Stable isotope composition data indicated microbial consumption of methane or propane in some of the samples. Evidence of the presence of microbes was initially determined by 4,6-diamidino 2-phenylindole dihydrochloride (DAPI) total direct counts of hydrate-associated sediments (mean = 1.5 × 109 cells g-1) and gas hydrate (mean = 1.0 × 106 cells ml-1). Small-subunit rRNA phylogenetic characterization was performed to assess the composition of the microbial community in one gas hydrate sample (AT425) that had no detectable associated sediment and showed evidence of microbial methane consumption. Bacteria were moderately diverse within AT425 and were dominated by gene sequences related to several groups of Proteobacteria, as well as Actinobacteria and low-G + C Firmicutes. In contrast, there was low diversity of Archaea, nearly all of which were related to methanogenic Archaea, with the majority specifically related to Methanosaeta spp. The results of this study suggest that there is a direct association between microbes and gas hydrate, a finding that may have significance for hydrocarbon flux into the Gulf of Mexico and for life in extreme environments.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC93283/PubMed CentralArticle
ORCID:
AuthorORCID
Nealson, Kenneth H.0000-0001-5189-3732
Additional Information:© 2001, American Society for Microbiology. Received 14 May 2001/Accepted 31 August 2001 Support was provided to R.S. by the Applied Gas Hydrate Research Program at Texas A&M University and to K.H.N. by the NASA Astrobiology program. We thank J. W. Ammerman for use of his fluorescent microscope, F. Carsey for providing travel support for B.D.L., D. A. DeFreitas for preparation of the GIS map, and the crew of the R. V. Powell for assistance with sample collection.
Funders:
Funding AgencyGrant Number
Texas A&M UniversityUNSPECIFIED
NASAUNSPECIFIED
Issue or Number:11
PubMed Central ID:PMC93283
Record Number:CaltechAUTHORS:LANaem01
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:LANaem01
Alternative URL:http://dx.doi.org/10.1128/AEM.67.11.5143-5153.2001
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2612
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:12 Apr 2006
Last Modified:02 Oct 2019 22:55

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