Identification of microbial key-indicators of oil contamination at sea through tracking of oil biotransformation: An Arctic field and laboratory study

• Published in: The Science of the total environment 2019-12, Vol.696, p.133715-133715, Article 133715
• Main Authors: Krolicka, Adriana, Boccadoro, Catherine, Nilsen, Mari Mæland, Demir-Hilton, Elif, Birch, Jim, Preston, Christina, Scholin, Chris, Baussant, Thierry
• Format: Article
• Language: English
• Subjects: Arctic Regions; Biodegradation, Environmental; Biomonitoring; Biotransformation; Colwellia; Crude oil; Environmental Monitoring; Estuaries; Microbial molecular markers; Oleispira; Petroleum - analysis; Petroleum - metabolism; Petroleum Pollution - analysis; Pollution; Seawater; Seawater - microbiology; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.133715

In this paper, a molecular analytical approach for detecting hydrocarbonoclastic bacteria in water is suggested as a proxy measurement for tracking petroleum discharges in industrialized or pristine aquatic environments. This approach is tested for general application in cold marine regions (freezing to 5 °C). We used amplicon sequencing and qPCR to quantify 16S rRNA and GyrB genes from oleophilic bacteria in seawater samples from two different crude oil enrichments. The first experiment was conducted in a controlled environment using laboratory conditions and natural North Sea fjord seawater (NSC) at a constant temperature of 5 °C. The second was performed in the field with natural Arctic seawater (ARC) and outdoor temperature conditions from −7 °C to around 4 °C. Although the experimental conditions for NSC and ARC differed, the temporal changes in bacterial communities were comparable and reflected oil biotransformation processes. The common bacterial OTUs for NSC and ARC had the highest identity to Colwellia rossensis and Oleispira antarctica rRNA sequences and were enriched within a few days in both conditions. Other typical oil degrading bacteria such as Alcanivorax (n-alkane degrader) and Cycloclasticus (polycyclic aromatic hydrocarbons degrader) were rapidly enriched only in NSC conditions. Both the strong correlation between Oleispira SSU gene copies and oil concentration, and the specificity of the Oleispira assay suggest that this organism is a robust bioindicator for seawater contaminated by petroleum in cold water environments. Further optimization for automation of the Oleispira assay for in situ analysis with a genosensing device is underway. The assay for Colwellia quantification requires more specificity to fewer Colwellia OTUs and a well-established dose-response relationship before those taxa are used for oil tracking purposes. [Display omitted] •Selection of oil-degrading bacterial OTUs as a proxy for rapid detection of oil in cold seawater•Colwellia OTUs dominant and diverse in all treatments, including control, and not oil-dose dependent•Oleispira response specific and oil-dose dependent•Performance of Oleispira assay appropriate for integration in autonomous real-time genosensing