Biodegradation of Crude Oil and Corexit 9500 in Arctic Seawater

McFarlin, Kelly M.; Perkins, Matt J.; Field, Jennifer A.; Leigh, Mary Beth

doi:10.3389/fmicb.2018.01788

Cited by 52 publications

(41 citation statements)

References 84 publications

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“…All of these ingredients have previously been shown to serve as substrates for microbial growth (14)(15)(16). The stimulation of cell growth by Corexit 9500A is therefore not surprising, and similar findings have been reported elsewhere (17)(18)(19).…”

Section: Resultssupporting

confidence: 80%

“…S11 to S13 in the supplemental material). A dispersant-stimulated enrichment of potential hydrocarbon degraders, such as Colwellia and Rhodobacteraceae, has also been observed in other studies (14,18,25,32). This observation is not surprising, as Corexit 9500A contains a large hydrocarbon fraction in the form of alkane side chains of DOSS and petroleum distillates.…”

Section: Douglas Channel/hecate Strait Dilbit Degradationsupporting

confidence: 74%

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Potential for Microbially Mediated Natural Attenuation of Diluted Bitumen on the Coast of British Columbia (Canada)

Schreiber

Fortin

Tremblay

et al. 2019

Appl Environ Microbiol

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Western Canada produces large amounts of bitumen, a heavy, highly weathered crude oil. Douglas Channel and Hecate Strait on the coast of British Columbia are two water bodies that may be impacted by a proposed pipeline and marine shipping route for diluted bitumen (dilbit). This study investigated the potential of microbial communities from these waters to mitigate the impacts of a potential dilbit spill. Microcosm experiments were set up with water samples representing different seasons, years, sampling stations, and dilbit blends. While the alkane fraction of the tested dilbit blends was almost completely degraded after 28 days, the majority of the polycyclic aromatic hydrocarbons (PAHs) remained. The addition of the dispersant Corexit 9500A most often had either no effect or an enhancing effect on dilbit degradation. Dilbit-degrading microbial communities were highly variable between seasons, years, and stations, with dilbit type having little impact on community trajectories. Potential oil-degrading genera showed a clear succession pattern and were for the most part recruited from the “rare biosphere.” At the community level, dispersant appeared to stimulate an accelerated enrichment of genera typically associated with hydrocarbon degradation, even in dilbit-free controls. This suggests that dispersant-induced growth of hydrocarbon degraders (and not only increased bioavailability of oil-associated hydrocarbons) contributes to the degradation-enhancing effect previously reported for Corexit 9500A. IMPORTANCE Western Canada hosts large petroleum deposits, which ultimately enter the market in the form of dilbit. Tanker-based shipping represents the primary means to transport dilbit to international markets. With anticipated increases in production to meet global energy needs, the risk of a dilbit spill is expected to increase. This study investigated the potential of microbial communities naturally present in the waters of a potential dilbit shipping lane to mitigate the effects of a spill. Here we show that microbial degradation of dilbit was mostly limited to n-alkanes, while the overall concentration of polycyclic aromatic hydrocarbons, which represent the most toxic fraction of dilbit, decreased only slightly within the time frame of our experiments. We further investigated the effect of the oil dispersant Corexit 9500A on microbial dilbit degradation. Our results highlight the fact that dispersant-associated growth stimulation, and not only increased bioavailability of hydrocarbons and inhibition of specific genera, contributes to the overall effect of dispersant addition.

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Section: Resultssupporting

confidence: 80%

Section: Douglas Channel/hecate Strait Dilbit Degradationsupporting

confidence: 74%

Potential for Microbially Mediated Natural Attenuation of Diluted Bitumen on the Coast of British Columbia (Canada)

Schreiber

Fortin

Tremblay

et al. 2019

Appl Environ Microbiol

View full text Add to dashboard Cite

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“…These include (but are not limited to) bacterial taxonomic groups of Pseudomonadales (Leahy et al ., ; Seo et al ., ), Acidobacter (Seo et al ., ; Peng et al ., ), Gammaproteobacteria and Actinobacteria (Militon et al ., ; Peng et al ., ), Chloroflexi, Planctomycetes and Bacteroidetes (Peng et al ., ) (Table S2). Specific genera previously demonstrated to be associated with hydrocarbon‐impacted sites and high molecular weight polyaromatic hydrocarbons, such as bacterial OTUs identified as Anaerolineaceae, Caldilineaceae (Zhang et al ., ) and Lutibacter (McFarlin et al ., ) are shown to be elevated in abundance in samples from shallow and deep soils of A and B relative to section C (Fig. A).…”

Section: Resultsmentioning

confidence: 99%

Spatial analysis of a hydrocarbon waste‐remediating landfarm demonstrates influence of management practices on bacterial and fungal community structure

Bergsveinson

Perry

Simpson

et al. 2019

Microbial Biotechnology

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Summary Cultivation of dedicated soil plots called ‘landfarms' is an effective technology for bioremediation of hydrocarbon waste generated by various industrial practices. To understand the influence of soil conditions on landfarm microbial communities, analysis of bacterial and fungal community structure using next‐generation sequencing at different sections and depths was performed across a hydrocarbon‐waste landfarm in Regina, Saskatchewan, Canada. While a core set of hydrocarbon‐associated bacterial and fungal taxa are present throughout the landfarm, unique bacterial and fungal operational taxonomic units are differentially abundant at sections within the landfarm, which correlate with differences in soil physiochemical properties and management practices. Increased frequency of waste application resulted in strong positive correlations between bacterial community assemblages and elevated amounts of oil, grease and F3 – F4 hydrocarbon fractions. In areas of standing water and lower application of hydrocarbon, microbial community structure correlated with soil pH, trace nutrients and metals. Overall, diversity and structure of bacterial communities remain relatively stable across the landfarm, while in contrast, fungal community structure appears more responsive to soil oxygen conditions. Results are consistent with the hypothesis that years of bioremediation activity have shaped microbial communities; however, several management practices can be undertaken to increase efficiency of remediation, including the removal of standing water and soil tilling across the landfarm.

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“…To date, several studies have reported increased rates of petroleum biodegradation with the addition of chemical dispersants, including in the Arctic (2,3), using either enrichment cultures (4)(5)(6)(7) or indigenous microbial communities (1)(2)(3)(8)(9)(10)(11), the latter of which are more likely to better reflect rates observed for in situ conditions. Recently, some studies appear to demonstrate the opposite effect, with dispersant addition negatively affecting oil biodegradation in indigenous (12) and cultured (13) seawater through processes such as suppressing the growth of some oil degrading bacteria or competitive substrate biodegradation, reintroducing some debate regarding the influence of chemical dispersants on petroleum biodegradation.…”

Section: Introductionmentioning

confidence: 99%

The Interactive Effects of Crude Oil and Corexit 9500 on Their Biodegradation in Arctic Seawater

Gofstein

Perkins

Field

et al. 2020

Appl Environ Microbiol

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The risk of petroleum spills coupled with the potential application of chemical dispersants as a spill response strategy necessitates further understanding of the fate of oil and dispersants and their interactive effects during biodegradation. Using Arctic seawater mesocosms amended with either crude oil, Corexit 9500, or both together, we quantified the chemical losses of crude oil and Corexit 9500 and identified microbial taxa implicated in their biodegradation based on shifts in the microbial community structure over a 30-day time course. Chemical analyses included total petroleum hydrocarbons (TPH), n-alkanes, branched alkanes, and polycyclic aromatic hydrocarbons (PAHs) for oil loss and the surfactant components dioctyl sodium sulfosuccinate (DOSS), Span 80, Tween 80, Tween 85, and the DOSS metabolite ethylhexyl sulfosuccinate (EHSS) for Corexit loss. Changes to the microbial communities and identification of key taxa were determined by 16S rRNA gene amplicon sequencing. The nonionic surfactants of Corexit 9500 (Span 80, Tweens 80+85) biodegraded rapidly, dropping to below the limits of detection within 5 days and prior to any detectable initiation of oil biodegradation. This resulted in no observable suppression of petroleum biodegradation in the presence of Corexit compared to that of oil alone. In contrast, biodegradation of DOSS was delayed in the presence of oil, based on the prolonged presence of DOSS concentrations and accumulation of the degradation intermediate EHSS that did not occur in the absence of oil. Microbial analyses revealed that oil and Corexit enriched different overall microbial communities, with the presence of both resulting in a community composition that shifted from one more similar to that of Corexit-only, then shifting to reflect the oil-only community over time, in parallel with the degradation of predominantly Corexit and then oil components. Some microbial taxa (Oleispira, Pseudofulvibacter, Roseobacter) responded to either oil or Corexit, suggesting that some organisms may be capable of utilizing both substrates. Together, these findings reveal interactive effects of crude oil and Corexit 9500 on chemical losses and microbial communities as they biodegrade, providing further insight into their fate when co-present in the environment. Importance Chemical dispersants such as Corexit 9500 are commonly used in oil spill response and are currently under consideration for use in the Arctic, where their fate and effects have not been well studied. This research was performed to determine the interactive effects of the co-presence of crude oil and Corexit 9500 on the degradation of components from each mixture and the associated microbial community structure over time in Arctic seawater. These findings will help yield a better understanding on the biodegradability of dispersant components applied to an oil spill, the temporal microbial community response to dispersed oil, and the fundamental microbial ecology of organic contaminant biodegradation processes in the Arctic marine environment.

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Biodegradation of Crude Oil and Corexit 9500 in Arctic Seawater

Cited by 52 publications

References 84 publications

Potential for Microbially Mediated Natural Attenuation of Diluted Bitumen on the Coast of British Columbia (Canada)

Potential for Microbially Mediated Natural Attenuation of Diluted Bitumen on the Coast of British Columbia (Canada)

Spatial analysis of a hydrocarbon waste‐remediating landfarm demonstrates influence of management practices on bacterial and fungal community structure

The Interactive Effects of Crude Oil and Corexit 9500 on Their Biodegradation in Arctic Seawater

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