Dataset Information

Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments.

ABSTRACT: Oil spills from pipeline ruptures are a major source of terrestrial petroleum pollution in cold regions. However, our knowledge of the bacterial response to crude oil contamination in cold regions remains to be further expanded, especially in terms of community shifts and potential development of hydrocarbon degraders. In this study we investigated changes of microbial diversity, population size and keystone taxa in permafrost soils at four different sites along the China-Russia crude oil pipeline prior to and after perturbation with crude oil. We found that crude oil caused a decrease of cell numbers together with a reduction of the species richness and shifts in the dominant phylotypes, while bacterial community diversity was highly site-specific after exposure to crude oil, reflecting different environmental conditions. Keystone taxa that strongly co-occurred were found to form networks based on trophic interactions, that is co-metabolism regarding degradation of hydrocarbons (in contaminated samples) or syntrophic carbon cycling (in uncontaminated samples). With this study we demonstrate that after severe crude oil contamination a rapid establishment of endemic hydrocarbon degrading communities takes place under favorable temperature conditions. Therefore, both endemism and trophic correlations of bacterial degraders need to be considered in order to develop effective cleanup strategies.

SUBMITTER: Yang S

PROVIDER: S-EPMC5122841 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

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Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments.

Yang Sizhong S Wen Xi X Shi Yulan Y Liebner Susanne S Jin Huijun H Perfumo Amedea A

Scientific reports 20161125

Oil spills from pipeline ruptures are a major source of terrestrial petroleum pollution in cold regions. However, our knowledge of the bacterial response to crude oil contamination in cold regions remains to be further expanded, especially in terms of community shifts and potential development of hydrocarbon degraders. In this study we investigated changes of microbial diversity, population size and keystone taxa in permafrost soils at four different sites along the China-Russia crude oil pipeli ...[more]

PMID: 27886221

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Project description:This study investigated the impacts of crude oil, diesel, and gasoline on the diversity of indigenous microbial communities as well as culturable microorganisms in the studied soil. Oil contamination led to shifts in the diversity of the soil's microbial communities, regardless of the contaminant applied. Unpolluted soils were more diverse and evenly distributed than contaminated samples. The domain Bacteria accounted for 65.15% of the whole microbial community. The bacterial phylum Proteobacteria dominated in all samples, followed by Actinobacteria and Acidobacteria. Pseudomonas with 28.15% of reads dominated in Proteobacteria, while Rhodococcus (3.07%) dominated in Actinobacteria, and Blastocatella (2.53%) dominated in Acidobacteria. The dominant fungal phyla across all samples were Ascomycota dominated by Penicillium (50.48% of sequences), and Zygomycota dominated by Mortierella (16.87%). Sequences similar to the archaeal phyla, Euryarchaeota and Thaumarchaeota, were also detected. The number of culturable microorganisms increased following the contamination and was higher in contaminated samples than in clean samples. Oil contamination also resulted in the enrichment of oil-degrading strains. Two bacteria, Serratia marcescens strain PL and Raoultella ornithinolytica PS, which were isolated from crude oil-contaminated soil, exhibited strong crude oil degradation ability. Strain PL was the most efficient strain and degraded 75.10% of crude oil, while strain PL degraded 65.48%, after 20 days of incubation. However, the mixed culture of the two strains was more effective than single strain and could achieve up to 96.83% of crude oil degradation, with a complete abatement of straight-chain hydrocarbons (from C12 to C25), and more than 91% removal of highly branched hydrocarbons, phytane and pristane, which are known to be more recalcitrant to biodegradation. Strains PS and PL are two newly isolated crude oil degraders that are not among the most prominent crude oil-degrading strains referenced in the literature. Therefore, their high degradation capacity makes them perfect candidates for the bioremediation of petroleum hydrocarbon contaminated environments.

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Project description:BackgroundBiochar amendments have been widely proposed as a conventional and efficient strategy to promote soil organic carbon (SOC) sequestration via negative priming. Unfortunately, the extent and biological mechanisms responsible for biochar-induced negative priming are still not fully understood. Despite traditional explanations focused on the environmental filtering mechanisms of biochar amendments on microbial biomass and community composition underlying the priming effect on SOC dynamics, whether and how a biochar-induced competitive interaction with keystone taxa determines SOC mineralization in natural ecosystems has been minimally explored.ResultsHere, we paid particular attention to the relationships between the diversity and network structure of soil bacterial and fungal communities and SOC mineralization. A 3-year field experiment was conducted comprising five treatments: no fertilization, conventional fertilization, and conventional fertilization with three rates of biochar amendments. Biochar amendments considerably increased soil moisture capacity and pH and subsequently shaped the composition and co-occurrence networks of soil bacterial and fungal communities. Importantly, network analysis revealed that the biochar amendments triggered the competitive interaction with putative keystone taxa in the bacterial and fungal networks. Structural equation modeling suggested that the competitive interaction with keystone taxa promoted bacterial and fungal diversity and consequently reduced carbohydrate catabolism and soil metabolic quotient. Stable isotope probing incubations further provided consistent evidence of competition by keystone taxa with the increases in bacterial and fungal diversity under the biochar amendments.ConclusionsWe found that biochar-induced competition with keystone taxa stimulated the bacterial and fungal diversity and consequently decreased SOC mineralization. The comprehensive understanding of the unexplored biological mechanisms underlying the biochar-induced negative priming may provide crucial implications for enabling SOC sequestration.

Dataset Information

Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments.

Publications

Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments.

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