Oil spills represent an overwhelming carbon input to the marine environment that immediately impacts the sea surface ecosystem. Microbial communities degrading the oil fraction that eventually sinks to the seafloor must also deal with hydrostatic pressure, which linearly increases with depth. Piezosensitive hydrocarbonoclastic bacteria are ideal candidates to elucidate impaired pathways following oil spills at low depth. In the present paper, we tested two strains of the ubiquitous Alcanivorax genus, namely A. jadensis KS_339 and A. dieselolei KS_293, which is known to rapidly grow after oil spills. Strains were subjected to atmospheric and mild pressure (0.1, 5 and 10 MPa, corresponding to a depth of 0, 500 and 1000 m, respectively) providing n-dodecane as sole carbon source. Pressures equal to 5 and 10 MPa significantly lowered growth yields of both strains. However, in strain KS_293 grown at 10 MPa CO2 production per cell was not affected, cell integrity was preserved and PO43− uptake increased. Analysis of its transcriptome revealed that 95% of its genes were downregulated. Increased transcription involved protein synthesis, energy generation and respiration pathways. Interplay between these factors may play a key role in shaping the structure of microbial communities developed after oil spills at low depth and limit their bioremediation potential.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was funded by FP-7 project Kill Spill (No. 312139, “Integrated Biotechnological Solutions for
Combating Marine Oil Spills”). The authors thank the support of King Abdullah University of Science and
Technology (baseline research funds to D.D.). F.M. was supported by Università degli Studi di Milano, DeFENS,
European Social Found (FSE) and Regione Lombardia (contract “Dote Ricerca”). Mr. Benjamin Buysschaert and
Ms. Nicole Hahn are kindly acknowledged for their help with flow cytometry analyses.