Marine microbial communities capable of hydrocarbon biodegradation along shipping routes in the Kivalliq region of the Canadian Arctic
The extreme cold and icy marine environment in the Canadian Arctic is not well understood regarding its potential for biodegradation of oil spills. Reduced ice cover due to climate change has led to increased human activities, with attendant risks of oil and fuel spills associated with shipping traffic. This threatens the marine ecosystem and well-being of Canadians living in Arctic communities that rely on the ocean for food and cultural livelihood. Naturally occurring hydrocarbon-degrading bacteria within the marine microbiome have the potential to catalyze biodegradation of crude oil compounds, with previous studies showing cold-adapted oil-degrading bacteria inhabiting different marine biomes in the Canadian Arctic. However, the Kivalliq region in Nunavut, Canada, which has been impacted by increased vessel traffic in Hudson Bay in recent decades, has not been investigated in this regard. Determination of the baseline microbiomes in pristine ice, seawater and surface sediment was complemented by mock oil spill microcosms in seawater and sediment to assess biodegradation potential in the Kivalliq marine environment. Incubations of seawater or sediment amended with crude oil were monitored over a 21-week period using 16S rRNA gene amplicon sequencing, metagenomics, cell counting and hydrocarbon geochemistry. Analysis of microbial baselines showed little variability in diversity or taxa in similar marine biomes apart from sites with fresher water. Seawater microcosms demonstrated growth from putative hydrocarbon-degrading organisms corresponding to losses in alkane hydrocarbons. Alkane and polycyclic aromatic hydrocarbon losses and detection of associated genes for hydrocarbon degradation corresponded with appearances of putative hydrocarbonoclastic taxa in sediment microcosms. The Kivalliq marine microbiome’s potential to mitigate pollution effects associated with oil spills suggests that incorporating microbial diversity and microbiome assessments into monitoring environmental change will lead to improved efficacy of spill bioremediation strategies and preparation measures in the Arctic.
hydrocarbon degradation, bioremediation, hudson bay, oil spill, hydrocarbonoclastic bacteria, environmental monitoring, baselines, microbiome
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