AUTHOR=Piceno Yvette M. , Reid Francine C. , Tom Lauren M. , Conrad Mark E. , Bill Markus , Hubbard Christopher G. , Fouke Bruce W. , Graff Craig J. , Han Jiabin , Stringfellow William T. , Hanlon Jeremy S. , Hu Ping , Hazen Terry C. , Andersen Gary L. 

TITLE=Temperature and injection water source influence microbial community structure in four Alaskan North Slope hydrocarbon reservoirs

JOURNAL=Frontiers in Microbiology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2014.00409

DOI=10.3389/fmicb.2014.00409

ISSN=1664-302X

ABSTRACT=<p>A fundamental knowledge of microbial community structure in petroleum reservoirs can improve predictive modeling of these environments. We used hydrocarbon profiles, stable isotopes, and high-density DNA microarray analysis to characterize microbial communities in produced water from four Alaskan North Slope hydrocarbon reservoirs. Produced fluids from Schrader Bluff (24–27°C), Kuparuk (47–70°C), Sag River (80°C), and Ivishak (80–83°C) reservoirs were collected, with paired soured/non-soured wells sampled from Kuparuk and Ivishak. Chemical and stable isotope data suggested Schrader Bluff had substantial biogenic methane, whereas methane was mostly thermogenic in deeper reservoirs. Acetoclastic methanogens (<italic>Methanosaeta</italic>) were most prominent in Schrader Bluff samples, and the combined δD and δ<sup>13</sup>C values of methane also indicated acetoclastic methanogenesis could be a primary route for biogenic methane. Conversely, hydrogenotrophic methanogens (e.g., Methanobacteriaceae) and sulfide-producing <italic>Archaeoglobus</italic> and <italic>Thermococcus</italic> were more prominent in Kuparuk samples. Sulfide-producing microbes were detected in all reservoirs, uncoupled from souring status (e.g., the non-soured Kuparuk samples had higher relative abundances of many sulfate-reducers compared to the soured sample, suggesting sulfate-reducers may be living fermentatively/syntrophically when sulfate is limited). Sulfate abundance via long-term seawater injection resulted in greater relative abundances of <italic>Desulfonauticus</italic>, <italic>Desulfomicrobium</italic>, and <italic>Desulfuromonas</italic> in the soured Ivishak well compared to the non-soured well. In the non-soured Ivishak sample, several taxa affiliated with <italic>Thermoanaerobacter</italic> and <italic>Halomonas</italic> predominated. Archaea were not detected in the deepest reservoirs. Functional group taxa differed in relative abundance among reservoirs, likely reflecting differing thermal and/or geochemical influences.</p>