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Comparison of surficial CO2 efflux to other measures of subsurface crude oil degradation

Journal of Contaminant Hydrology

By:
, , ,
DOI: 10.1016/j.jconhyd.2014.06.006

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Abstract

At a spill site near Bemidji, Minnesota, crude oil at the water table has been undergoing anaerobic biodegradation for over 30 years. Previous work at this site has shown that methane produced from biodegradation of the oil migrates upward and is oxidized in a methanotrophic zone midway between the water table and the surface. To compare microbial activity measurement methods from multiple locations in the oil body, surficial carbon dioxide efflux, methanogen and methanotroph concentrations, and oil degradation state were collected. Carbon dioxide effluxes over the oil body averaged more than four times those at the background site. Methanotrophic bacteria concentrations measured using pmoA were over 105 times higher above the oil-contaminated sediments compared with the background site. Methanogenic archaea measured using mcrA ranged from 105 to over 107 in the oil and were below detection in the background. Methanogens correlated very well with methanotroph concentrations (r = 0.99), n-alkylcyclohexane losses as a proxy for degradation state (r = − 0.96), and somewhat less well with carbon dioxide efflux (r = 0.92). Carbon dioxide efflux similarly correlated to methanotroph concentrations (r = 0.90) and n-alkylcyclohexane losses (r = − 0.91).

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Comparison of surficial CO2 efflux to other measures of subsurface crude oil degradation
Series title:
Journal of Contaminant Hydrology
DOI:
10.1016/j.jconhyd.2014.06.006
Volume
164
Year Published:
2014
Language:
English
Publisher:
Elsevier
Contributing office(s):
National Research Program - Western Branch
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Contaminant Hydrology
First page:
275
Last page:
284
Number of Pages:
10
Country:
United States
State:
Minnesota
City:
Bemidji
Datum:
North American Datum 1983
Projection:
Universal Transverse Mercator projection, Zone 15 N