GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Society of Exploration Geophysicists  (3)
Material
Publisher
  • Society of Exploration Geophysicists  (3)
Person/Organisation
Language
Years
Subjects(RVK)
  • 1
    Online Resource
    Online Resource
    In‐situ apparent conductivity measurements and microbial population distribution at a hydrocarbon‐contaminated site
    Society of Exploration Geophysicists ; 2004
    In:  GEOPHYSICS Vol. 69, No. 1 ( 2004-01), p. 56-63
    Details
    In: GEOPHYSICS, Society of Exploration Geophysicists, Vol. 69, No. 1 ( 2004-01), p. 56-63
    Abstract: We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light nonaqueous‐phase liquid (LNAPL). The bulk conductivity was measured using in‐situ vertical resistivity probes; the most probable number method was used to characterize the spatial distribution of aerobic heterotrophic and oil‐degrading microbial populations. The purpose of this study was to assess if high conductivity observed at aged LNAPL‐impacted sites may be related to microbial degradation of LNAPL. The results show higher bulk conductivity coincident with LNAPL‐impacted zones, in contrast to geoelectrical models that predict lower conductivity in such zones. The highest bulk conductivity was observed to be associated with zones impacted by residual and free LNAPL. Data from bacteria enumeration from sediments close to the resistivity probes show that oil‐degrading microbes make up a larger percentage (5–55%) of the heterotrophic microbial community at depths coincident with the higher conductivity compared to ∼5% at the uncontaminated location. The coincidence of a higher percentage of oil‐degrading microbial populations in zones of higher bulk conductivity suggests that the higher conductivity in these zones may result from increased fluid conductivity related to microbial degradation of LNAPL, consistent with geochemical studies that suggest that intrinsic biodegradation is occurring at the site. The findings from this study point to the fact that biogeochemical processes accompanying biodegradation of contaminants can potentially alter geoelectrical properties of the subsurface impacted media.
    Type of Medium: Online Resource
    ISSN: 0016-8033 , 1942-2156
    URL: Article
    DOI: 10.1190/1.1649375
    RVK:
    UA 4068.4
    Language: English
    Publisher: Society of Exploration Geophysicists
    Publication Date: 2004
    detail.hit.zdb_id: 2033021-2
    detail.hit.zdb_id: 2184-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Temporal geophysical signatures from contaminant-mass remediation
    Society of Exploration Geophysicists ; 2009
    In:  GEOPHYSICS Vol. 74, No. 4 ( 2009-07), p. B113-B123
    Details
    In: GEOPHYSICS, Society of Exploration Geophysicists, Vol. 74, No. 4 ( 2009-07), p. B113-B123
    Abstract: We have previously documented changes in bulk electrical conductivity, self-potential (SP), and ground-penetrating-radar (GPR) reflections in a field setting caused by biogeochemical transformations of hydrocarbon-contaminated media. These transformations are associated with hydrocarbon biodegradation. The results of surface geophysical surveys acquired in 1996, 2003, and 2007 document changes in geophysical signatures associated with removing hydrocarbon mass in the contaminated zone. Initial investigations in 1996 showed that relative to background, the contaminated area was characterized by higher bulk electrical conductivity, positive SP anomaly, and attenuated GPR reflections. Repeated surveys in 2003 and 2007 over the contaminated area showed that in 2007, the bulk electrical conductivityhad reverted to near-background conditions, the positive SP anomaly became more negative, and the zone of attenuated GPR reflections showed increased signal strength. Removal of hydrocarbon mass in the vadose zone over the plume by a soil vapor-extraction system installed in 2001 was primarily responsible for the changing geophysical responses. Although chemical data from groundwater showed a [Formula: see text]-thick con-ductive plume in 2007, the plume was not imaged by elec-trical resistivity. Forward modeling suggests that apparent bulk electrical conductivity of the saturated zone plume has to be three to five times higher than background values to be imaged by electrical resistivity. We suggest that removing hydrocarbon-contaminant-mass reduction by natural or engineered bioremediation can be imaged effectively by temporal geophysical surveys.
    Type of Medium: Online Resource
    ISSN: 0016-8033 , 1942-2156
    URL: Article
    DOI: 10.1190/1.3139769
    RVK:
    UA 4068.4
    Language: English
    Publisher: Society of Exploration Geophysicists
    Publication Date: 2009
    detail.hit.zdb_id: 2033021-2
    detail.hit.zdb_id: 2184-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Ground-penetrating radar profiles over multiple steel tanks: Artifact removal through effective data processing
    Society of Exploration Geophysicists ; 2007
    In:  GEOPHYSICS Vol. 72, No. 6 ( 2007-11), p. J77-J83
    Details
    In: GEOPHYSICS, Society of Exploration Geophysicists, Vol. 72, No. 6 ( 2007-11), p. J77-J83
    Abstract: This paper describes some ground-penetrating radar (GPR) results to characterize steel tanks buried in the subsoil of an urban center. Tanks were installed in the first Brazilian geophysical test site located at the Institute of Astronomy, Geophysics, and Atmospheric Science (IAG) of the University of São Paulo (USP). This paper also presents an effec-tive procedure for removal of hyperbolic artifacts associated with GPR reflections between multiple steel tanks. One hundred sixty-five GPR profiles of [Formula: see text], [Formula: see text] , and [Formula: see text] (shielded bistatic antennae) were measured. The work was done in two distinct places: on the geophysical test site of the IAG/USP in the city of São Paulo, Brazil, and in an area formerly occupied by a truck cleaning, refueling, and maintenance facility, located in Oscoda, northeastern Michigan, USA. Predictive deconvolution and Kirchhoff migration were first used to improve vertical and lateral resolution. To minimize the hyperbolic artifacts caused by reflections between tanks, high-pass filtering was applied to data. Then, Hilbert transforms emphasize the location of the steel tanks in an energy cross-section form. Further GPR processing, such as vertical and depth slices, were very important to improve visualization and localization of steel tanks and pipes in the subsurface.
    Type of Medium: Online Resource
    ISSN: 0016-8033 , 1942-2156
    URL: Article
    DOI: 10.1190/1.2783412
    RVK:
    UA 4068.4
    Language: English
    Publisher: Society of Exploration Geophysicists
    Publication Date: 2007
    detail.hit.zdb_id: 2033021-2
    detail.hit.zdb_id: 2184-2
    SSG: 16,13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...