PAHs in high Arctic copepods Calanus hyperboreus following exposure of residues from in situ burning of oil spill.

In situ burning of marine oil spills reduces the total amount of oil in the environment, but a negative side effect may be the generation of environmentally hazardous polycyclic aromatic hydrocarbons (PAHs) that may pose a risk for bioaccumulation, particularly in organisms having a high lipid content. In this study uptake of PAHs from oil and burn residue were examined in the high arctic copepod Calanus hyperboreus. A major part of the low ring number petrogenic PAHs in the oil was removed during burning and relative higher concentrations of pyrogenic high ring number PAHs was found in the burn residue. This suggests that burning markedly reduces the general PAH exposure load. Furthermore, the pyrogenic PAHs generated during the burn were not bioconcentrated to quantifiable levels in the copepods. We conclude that in situ burning can mitigate the potential risk of PAH uptake for copepods and other pelagic organisms in the marine environment as the pyrogenic PAHs only pose low risk for uptake from the water by the copepods and other pelagic organisms.

Biodegradation of marine oil spills in the Arctic with a Greenland perspective.

New economic developments in the Arctic, such as shipping and oil exploitation, bring along unprecedented risks of marine oil spills. Microorganisms have played a central role in degrading and reducing the impact of the spilled oil during past oil disasters. However, in the Arctic, and in particular in its pristine areas, the self-cleaning capacity and biodegradation potential of the natural microbial communities have yet to be uncovered. This review compiles and investigates the current knowledge with respect to environmental parameters and biochemical constraints that control oil biodegradation in the Arctic. Hereby, seawaters off Greenland are considered as a case study. Key factors for biodegradation include the bioavailability of hydrocarbons, the presence of hydrocarbon-degrading bacteria and the availability of nutrients. We show how these key factors may be influenced by the physical oceanographic conditions in seawaters off Greenland and other environmental parameters including low temperature, sea ice, sunlight regime, suspended sediment plumes and phytoplankton blooms that characterize the Arctic. Based on the acquired insights, a first qualitative assessment of the biodegradation potential in seawaters off Greenland is presented. In addition to the most apparent Arctic characteristics, such as low temperature and sea ice, the impact of typical Arctic features such as the oligotrophic environment, poor microbial adaptation to hydrocarbon degradation, mixing of stratified water masses, and massive phytoplankton blooms and suspended sediment plumes merit to be topics of future investigation.