Browsing by Subject "oil spill"

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  • Lamendella, Regina; Strutt, Steven; Borglin, Sharon; Chakraborty, Romy; Tas, Neslihan; Mason, Olivia U.; Hultman, Jenni; Prestat, Emmanuel; Hazen, Terry C.; Jansson, Janet K. (2014)
  • Raitosalo, Amanda (Helsingin yliopisto, 2020)
    Heavy traffic and transportation of crude oil makes the Baltic Sea vulnerable to accidental oil spills. Currently mechanical removal is the recommended response method in the Baltic Sea region. However, in bad weather conditions, mechanical oil removal can be challenging, and it may be justifiable to consider alternative response methods in order to protect valuable natural sites. Chemical dispersants are mixtures of surfactants and solvents and are used to treat spilled oil in marine environments. Dispersants break oil slicks into small droplets, which are more readily available for microbial biodegradation. Large-scale studies on the effects of dispersants on microbial communities and biodegradation rates have not been conducted in the Baltic Sea. During this 40-day microcosm study, native microbial communities from the Gulf of Finland were exposed to crude oil, dispersant or their combination. Additional nutrients were not supplied during the study. The experiment was carried out at 10 °C, and samples were collected at days 1, 2, 5, 14 and 40. The amount and expression of genes related to microbial abundance, oil biodegradation and nutrient cycling was assessed by quantitative PCR. Extracellular enzymatic activities of microbes were studied utilizing high throughput robotics. The results indicated that microbial response was primarily elevated in samples containing dispersant. Dispersant was degraded almost completely during the study period. Biodegradation of C21-40 hydrocarbons in crude oil was not enhanced with the addition of dispersant. On genetic level, the abundance and expression of alkane monooxygenase gene (alkB) was elevated in samples with dispersant, whereas the abundance and expression of polycyclic aromatic ring-hydroxylating dioxygenase gene (PAH-RHD) was enhanced also in samples containing crude oil.
  • Nevalainen, Maisa Katariina; Vanhatalo, Jarno; Helle, Inari (2019)
    Risk of an Arctic oil spill has become a global matter of concern. Climate change induced opening of shipping routes increases the Arctic maritime traffic which exposes the area to negative impacts of potential maritime accidents. Still, quantitative analyses of the likely environmental impacts of such accidents are scarce, and our understanding of the uncertainties related to both accidents and their consequences is poor. There is an obvious need for analysis tools that allow us to systematically analyze the impacts of oil spills on Arctic species, so the risks can be taken into account when new sea routes or previously unexploited oil reserves are utilized. In this paper, an index‐based approach is developed to study exposure potential (described via probability of becoming exposed to spilled oil) and sensitivity (described via oil‐induced mortality and recovery) of Arctic biota in the face of an oil spill. First, a conceptual model presenting the relevant variables that contribute to exposure potential and sensitivity of key Arctic marine functional groups was built. Second, based on an extensive literature review, a probabilistic estimate was assigned for each variable, and the variables were combined to an index representing the overall vulnerability of Arctic biota. The resulting index can be used to compare the relative risk between functional groups and accident scenarios. Results indicate that birds have the highest vulnerability to spilled oil, and seals and whales the lowest. Polar bears’ vulnerability varies greatly between seasons, while ice seals’ vulnerability remains the same in every accident scenario. Exposure potential of most groups depends strongly on type of oil, whereas their sensitivity contains less variation.
  • Helle, Inari; Jolma, Ari; Venesjärvi, Riikka (2016)
    Large-scale oil spills can have adverse effects on biodiversity in coastal areas where maritime oil transportation is intense. In this article we conducted a spatial risk assessment to study the risk that potential tanker accidents pose to threatened habitat types and species living in the northern Baltic Sea, which has witnessed a rapid increase in maritime oil transportation within the past two decades. We applied a probabilistic method, which combines three components: a Bayesian network describing tanker accidents and uncertainties related to them, probabilistic maps showing the movement of oil, and a database of threatened species and habitats in the area. The results suggest that spatial risk posed by oil spills varies across the area, and does not correspond, for example, to the frequency of accidents in a given area. The relative risk is highest for seashore meadows, which is important to take into account when managing these habitats. Our analysis underlines the importance of a thorough risk assessment, which is not only based solely on one or two specific factors such as accident probabilities or the trajectories of spilled oil but also contains as broad a view of the consequences as possible. We believe that the probabilistic methodology applied in the study will be of high interest to people who have to cope with uncertainties typical for environmental risk assessment and management.