title: Influence of crude oil on changes of bacterial communities in Arctic sea-ice.
abstract: The danger of a petroleum hydrocarbon spillage in the polar, ice-covered regions is increasing due to oil exploration in Arctic offshore areas and a growing interest in using the Northern Sea Route (NSR) as an alternative transportation route for Arctic oil and gas. However, little is known about the potential impact of accidental oil spills on this environment. We investigated the impact of crude oil on microbial community composition in six different Arctic sea-ice samples incubated with crude oil at 1 degrees C in microcosms for one year. Alterations in the composition of bacterial communities were analyzed with the culture-independent molecular methods DGGE (denaturing gradient gel electrophoresis) and FISH (fluorescence in situ hybridization). DGGE, FISH and cultivation methods revealed a strong shift in community composition toward the gamma-proteobacteria in sea-ice and melt pool samples incubated with crude oil. Marinobacter spp., Shewanella spp. and Pseudomonas spp. were the predominant phylotypes in the oil-treated microcosms. The ability of indigenous sea-ice bacteria to degrade hydrocarbons at low temperature (1 degrees C) was tested using four representative strains cultivated from sea-ice enriched with crude oil. [14C]Hexadecane was degraded by the sea-ice isolates at 20-50% capacity of the mesophilic type strain Marinobacter hydrocarbonoclasticus, a known hydrocarbon degrader, incubated at 22 degrees C.
authors.affiliation: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany. bgerdes@awi-bremerhaven.de
authors.forename: Birte
authors.initials: B
authors.lastname: Gerdes
authors.forename: Robin
authors.initials: R
authors.lastname: Brinkmeyer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Dieckmann
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Helmke
mesh_terms: D000473:Alkanes; D001110:Arctic Regions; D001483:Base Sequence; D001673:Biodegradation, Environmental; D002250:Carbon Radioisotopes; D017931:DNA Primers; D017753:Ecosystem; D020563:Gammaproteobacteria / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D046448:Ice Cover / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010578:Petroleum / Q000378:metabolism / Q000633:toxicity*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D000473:Alkanes; D002250:Carbon Radioisotopes; D017931:DNA Primers; D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; C007932:n-hexadecane