The Arctic attracts not only with beautiful motifs or as a research site for climate change impacts. Economically, too, attention is focused on the numerous resources and short transport routes between the major markets of Asia, Europe and North America. But this also increases the risk of disasters involving fossil fuels and crude oil, as the past has shown impressively. The climatic conditions and the lack of infrastructure prevent an efficient fight against such accidents. Canadian microbiologists and aquatic researchers have now discovered bacterial communities that could help change that.
The study, conducted on the Labrador coast in eastern Canada, found several genera of bacteria in sediments that occur there naturally and have the ability to break down both diesel and crude oil. This showed that different genera have different preferences in terms of oil products. The degradation of oil products was further stimulated when the researchers added nutrients such as nitrogen and phosphorus. “The bacteria may represent key players in the response to Arctic marine oil spills,” says study leader Dr. Casey Hubert, associate professor of geomicrobiology at the University of Calgary. “The study also confirmed that providing nutrients can enhance hydrocarbon biodegradation under these low temperature conditions.”
In their study, the research group created a miniature oil spill in bottles and exposed artificial seawater (to avoid impurities and deviations) and sediments from the Labrador coast (from a depth of about 140 metres) to either diesel or crude oil. In addition, different nutrients were added to the samples in varying amounts. The whole was carried out under near-arctic conditions, at 4°C water temperature and over several weeks. This showed that the bacteria not only have preferences for either diesel or crude oil, but that they also have a tolerance level that depends on the type of oil product. Crude oil degradation stopped at 10 times lower levels than diesel, which may be due to crude oil’s higher toxicity, the team suspects. Nevertheless, adding nutrients can massively increase the degradation rates of petroleum products shortly after an accident involving crude oil or diesel in cold conditions, the team concludes in their paper, which is published in the journal Applied and Environmental Microbiology.
The study area, the Labrador coast, was not chosen at random. Along the coast runs one of the most important transport routes from the urban centres on the east coast of Canada to the north and the Northwest Passage. In addition, the provincial government plans to expand the oil sector in the region by 2030. Because the study’s lead author, doctoral student Sean Murphy, is from the region and knows of its advantages and disadvantages, he sought ways to develop oil spill response strategies.
The results of the work are a further step towards intervening as quickly as possible in the event of a possible accident involving oil products in the sensitive Arctic regions. “As climate change extends ice-free periods and increasing industrial activity takes place in the Arctic, it is important to understand the ways in which the Arctic marine microbiome will respond if there is an oil or fuel spill,” Dr Hubert said. At the same time, the size and remoteness of the areas prevent a rapid response and the lack of infrastructure complicates clean-up measures, so new and easily deployable options are needed. For the accident of the tanker Exxon Valdez on 24 March 1989 in Alaska clearly showed these difficulties and limits of rescue measures. This resulted in more than 2,000 kilometres of coastline being so badly polluted that the effects can still be felt and seen today, more than 30 years later.
Dr Michael Wenger, PolarJournal
Link to the study: Sean M. C. Murphy, María A. Bautista, Margaret A. Cramm, Casey R. J. Hubert. Biodegradation of diesel and crude oil by Labrador Sea cold adapted microbial communities. Applied and Environmental Microbiology, 2021; DOI: 10.1128/AEM.00800-21.
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