Crude oil buried in intertidal sands may be exposed to alternating oxic and anoxic conditions but the effect of this tidally induced biogeochemical oscillation remains poorly understood, limiting the effectiveness of remediation and managing efforts after oil spills. Here, we used a combination of metatranscriptomics and genome-resolved metagenomics to study microbial activities in oil-contaminated sediments during oxic-anoxic cycles in laboratory chambers that closely emulated in situ conditions. Approximately 5-fold higher reductions in the total petroleum hydrocarbons were observed in the oxic as compared to the anoxic phases with a relatively constant ratio between aerobic and anaerobic oil decomposition rates even after prolonged anoxic conditions. Metatranscriptomics analysis indicated that the oxic phases promoted oil biodegradation in subsequent anoxic phases by microbially mediated reoxidation of alternative electron acceptors like sulfide and by providing degradation-limiting nitrogen through biological nitrogen fixation. Most population genomes reconstructed from the mesocosm samples represented uncultured taxa and were present typically as members of the rare biosphere in metagenomic data from uncontaminated field samples, implying that the intertidal communities are adapted to changes in redox conditions. Collectively, these results have important implications for enhancing oil spill remediation efforts in beach sands and coastal sediments and underscore the role of uncultured taxa in such efforts.
|Number of pages||12|
|Journal||Environmental Science and Technology|
|State||Published - Aug 18 2020|
Bibliographical noteFunding Information:
This research was made possible by grants from The Gulf of Mexico Research Initiative including RFP V grant no. 321611-00, C-IMAGE II, C-IMAGE III, and Deep-C consortia. Data are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at https://data.gulfresearchinitiative.org (R5.x278.000:0001).
Copyright © 2020 American Chemical Society.
ASJC Scopus subject areas
- Chemistry (all)
- Environmental Chemistry