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Past oil disasters have shown that only 15 to 25% of the oil can be effectively removed from the marine environments. Photo: Janne Fritt-Rasmussen.
Greenland Oil Spill Response conducts training to be prepared for oil spills in the Arctic. Photo: Lonnie Bogø Wilms.
Leendert Vergeynst, Aarhus Universiet og Lorenz Meire, Grønlands Naturinstitut, samler havis fra Godthåbsfjord i Grønland for at studere olie-spisende bakterier i arktisk havvand. Foto: Wieter Boone.
Schematic diagram of Arctic-specific conditions that affect microbial degradation of oil spills: A) Sea ice and icebergs hamper wind/wave-induced mixing in the upper water column and cause a thicker oil slick, which, in combination with low temperature, reduces evaporation, dispersion and dissolution. All these effect result in larger oil droplets, which microbes cannot degrade. B) Most oil compounds are not soluble in water. Therefore, the bacteria form a biofilm on the oil droplets in order to be able to consume the oil compounds. A small fraction of the oil compounds is water-soluble and thus consumed by both biofilm and free-living bacteria. C) Oil-mineral and oil-phytoplankton aggregates, which may enhance oil sedimentation ('dirty blizzards'), are formed upon interaction with sediment plumes from glaciers and phytoplankton blooms, respectively. D) Photooxidation by ultraviolet radiation from sunlight can be important, especially during summer. Ultraviolet light helps degrading oil molecules, but at the same time, the oil toxicity towards marine organisms may increase. E) Deep mixing of the water column and upwelling cause nutrient replenishment. Oceanographical conditions may thus be important to provide fresh nutrients for oil-eating microbes. (Credit: Leendert Vergeynst)

2018.03.08 | Public / media

Oil-eating microbes are challenged in the Arctic

Bacteria play a major role in cleaning up oil spills and mitigating its environmental impacts. In a review published in ‘Science of the Total Environment’, researchers from Aarhus University, Denmark, examine the major limiting factors for microbial degradation in Arctic environments.