Microbial community distribution in sediments from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

Colwell, Frederick S.; Schwartz, Adam; Briggs, Brandon R.

doi:10.1016/j.marpetgeo.2009.12.012

Cited by 12 publications

(10 citation statements)

References 47 publications

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“…The core was processed onsite and a total of 261 subsamples were collected. Selected subsamples were processed onsite to extract pore water for both onsite and subsequent laboratory analyses ; to obtain sediment samples for microbiological analyses (Colwell et al, 2011) and physical properties studies Dai et al, 2011); and to obtain gas samples for geochemical analyses . In addition, eleven samples from the inferred gas hydrate-bearing intervals were stored for subsequent analyses, including four preserved in methane-filled pressure vessels and seven preserved in liquid nitrogen (Kneafsey et al, 2011;Lu et al, 2011;Stern et al, 2011).…”

Section: Core Program Resultsmentioning

confidence: 99%

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Overview of scientific and technical program

Hunter

Collett

Boswell

et al. 2011

Marine and Petroleum Geology

188

104

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Section: Core Program Resultsmentioning

confidence: 99%

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Overview of scientific and technical program

Hunter

Collett

Boswell

et al. 2011

Marine and Petroleum Geology

188

104

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“…The size of the restricted samples was determined by capillary gel electrophoresis using an ABI Prism 3100 Genetic Analyzer at the Oregon State University Center for Genome Research and Biotechnology. Analysis of the terminal restriction fragments (TRFs) was performed as previously described (Colwell et al ., ).…”

Section: Methodsmentioning

confidence: 97%

Bacterial dominance in subseafloor sediments characterized by methane hydrates

Briggs

Inagaki

Morono

et al. 2012

FEMS Microbiol Ecol

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The degradation of organic carbon in subseafloor sediments on continental margins contributes to the largest reservoir of methane on Earth. Sediments in the Andaman Sea are composed of ~ 1% marine-derived organic carbon and biogenic methane is present. Our objective was to determine microbial abundance and diversity in sediments that transition the gas hydrate occurrence zone (GHOZ) in the Andaman Sea. Microscopic cell enumeration revealed that most sediment layers harbored relatively low microbial abundance (10(3)-10(5) cells cm(-3)). Archaea were never detected despite the use of both DNA- and lipid-based methods. Statistical analysis of terminal restriction fragment length polymorphisms revealed distinct microbial communities from above, within, and below the GHOZ, and GHOZ samples were correlated with a decrease in organic carbon. Primer-tagged pyrosequences of bacterial 16S rRNA genes showed that members of the phylum Firmicutes are predominant in all zones. Compared with other seafloor settings that contain biogenic methane, this deep subseafloor habitat has a unique microbial community and the low cell abundance detected can help to refine global subseafloor microbial abundance.

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“…These whole-round core sections, samples stored in bags, and special samples (e.g., for microbiology) were labeled in the field for particular analyses (e.g., physical property moisture and density (MAD)), and were shipped to various government and academic research laboratories for initial evaluation and project-specific testing (Colwell et al, 2011;Kneafsey, 2011;Lorenson et al, 2011;Torres et al, 2011). Interstitial water was removed from designated samples at the well site (Torres et al, 2011).…”

Section: Offsite Laboratory Programmentioning

confidence: 99%

“…The present study also provides comparisons to the physical properties test program conducted as part of the Hot Ice well, drilled during 2003 and 2004 in the Ugnu and West Sak formations, although it did not recover gas hydrate (Sigal et al, 2005(Sigal et al, , 2009). The Mount Elbert physical property analyses are also useful complements to or provide input values for sedimentologic studies , petrophysical analyses, pore-water and gasgeochemistry studies Torres et al, 2011), microbiological studies (Colwell et al, 2011), and a variety of modeling investigations .…”

Section: Introductionmentioning

confidence: 99%

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

Winters

Walker

Hunter

et al. 2011

Marine and Petroleum Geology

100

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a b s t r a c tThis study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4 m-627.9 m); unit C-GH1 (649.8 m-660.8 m); and unit C-GH2 (663.2 m-666.3 m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average ''plug'' intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7 mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.Published by Elsevier Ltd.

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Microbial community distribution in sediments from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

Cited by 12 publications

References 47 publications

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Overview of scientific and technical program

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Overview of scientific and technical program

Bacterial dominance in subseafloor sediments characterized by methane hydrates

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

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