Naphthalene biodegradation in temperate and arctic marine microcosms

Abstract

Naphthalene, the smallest polycyclic aromatic hydrocarbon (PAH), is found in abundance in crude oil, its major source in marine environments. PAH removal occurs via biodegradation, a key process determining their fate in the sea. Adequate estimation of PAH biodegradation rates is essential for environmental risk assessment and response planning using numerical models such as the oil spill contingency and response (OSCAR) model. Using naphthalene as a model compound, biodegradation rate, temperature response and bacterial community composition of seawaters from two climatically different areas (North Sea and Arctic Ocean) were studied and compared. Naphthalene degradation was followed by measuring oxygen consumption in closed bottles using the OxiTop(®) system. Microbial communities of untreated and naphthalene exposed samples were analysed by polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and pyrosequencing. Three times higher naphthalene degradation rate coefficients were observed in arctic seawater samples compared to temperate, at all incubation temperatures. Rate coefficients at in situ temperatures were however, similar (0.048 day(-1) for temperate and 0.068 day(-1) for arctic). Naphthalene biodegradation rates decreased with similar Q10 ratios (3.3 and 3.5) in both seawaters. Using the temperature compensation method implemented in the OSCAR model, Q10 = 2, biodegradation in arctic seawater was underestimated when calculated from the measured temperate k1 value, showing that temperature difference alone could not predict biodegradation rates adequately. Temperate and arctic untreated seawater communities were different as revealed by pyrosequencing. Geographic origin of seawater affected the community composition of exposed samples.

Hydrocarbon biodegradation by Arctic sea-ice and sub-ice microbial communities during microcosm experiments, Northwest Passage (Nunavut, Canada)

“…Nonetheless, naphthalene-degrader microbes in cold Arctic ecosystems are as efficient as their temperate counterparts (Bagi et al 2014). Assuming the degradation rate observed during our experiment would persist, 15 more days would be needed for the complete degradation of these components.…”

“…8). Moritella was recently reported to be the second most abundant genus in naphthalene-spiked Arctic seawater (Bagi et al 2014), whereas the genus Algicola has not been previously described as oil-degrader. It is unclear if Algicola strains metabolized the added hydrocarbons or if they were rather secondary consumers that profited from other compounds released by oil-degrading bacteria.…”

Marine Oil-Degrading Microorganisms and Biodegradation Process of Petroleum Hydrocarbon in Marine Environments: A Review

“…Shi et al have found that 91.1 % of nalkane was degraded in 7 days, while the degradation rate of Naphthalene, 1-methylnaphthalene, 2-methylnaphtha-lene, 2,6-dimethylnaphthalene, and phenanthrene Vibrio cyclotrophicus sp.nov. [35] Naphthalene, anthracene, phenanthrene, and pyrene Aeram onas punctata TII [14,53] Phenanthrene and Chrysene Vibrio, Pseudoalteromonas, Marinomonas [31] n-Alkanes aromatic hydrocarbon, naphthalene, phenanthrene and anthracene Cycloclasticus oligotrophus [23,73] n-Alkanes, branched alkanes and alkylbenzenes Alcanivorax sp. [22,29,30,48,75] Aliphatic hydrocarbons, alkanoles, and alkanoates Oleiphilusand, Oleispira [28,74] Alkanes…”

Biodegradation of dispersed oil in natural seawaters from Western Greenland and a Norwegian fjord

“…Oil compounds may be degraded by a variety 1 3 of marine microbes, including bacteria, fungi, and algae (Prince 2005). While hydrocarbon-degrading bacteria in temperate seawater usually include members of the classes Alphaproteobacteria and Gammaproteobacteria, oil-polluted Arctic seawater and marine ice often become enriched by Gammaproteobacteria (Bowman and McCuaig 2003;Yakimov et al 2004;Deppe et al 2005;Gerdes et al 2005;Brakstad et al 2008;Bagi et al 2014;McFarlin et al 2014a;Garneau et al 2016). In particular, the Exxon Valdez grounding in Prince Willam Sound in 1989 drew public attention to oil biodegradation of oil discharged in the Arctic, and bioremediation was used as a secondary treatment of stranded oil in the Arctic (Bragg et al 1994).…”

“…Delille et al 1998aDelille et al , b, 2009Bagi et al 2014;McFarlin et al 2014b;Kristensen et al 2015;Scheibye et al 2017). In this study, we compared biodegradation of small oil-droplet dispersions at low temperature, using natural non-amended seawater from Western Greenland (Disko Bay) and temperate seawater from a Norwegian fjord acclimated to low temperature.…”