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Stable oxygen and carbon isotopes from the planktonic foraminifera Neogloboquadrina pachyderma in the Western Arctic surface sediments: Implications for water mass distribution
Get PDFNeogloboquadrina pachyderma is the most abundant planktonic foraminifera species found in the modern polar oceans. The δ18O and δ13C of N. pachyderma from the Western Arctic Ocean sediments were analyzed to reveal the implications of the proxies to environmental changes. The ±18O from N. pachyderma in the Chukchi Sea reflect the water mass distribution in this area. Heavier ±18O values were found along the Anadyr Current (AC) and lighter values in the central and eastern Chukchi Sea. These may reflect the freshwater signal from the Alaska Coastal Current (ACC) and Bering Sea Shelf Water (BSSW). The light δ18O signature in the high Arctic basin comes from the freshwater stored in the Arctic surface layer. The δ13C distribution pattern in the Chukchi Sea is also influenced by the current system. High primary productivity along the AC results in heavy δ13C. The relatively low primary productivity and the freshwater component from the BSSW and ACC may be the reason for this light δ13C signal in the central and eastern Chukchi Sea. Our data reveal the importance of well ventilated Pacific Water through the Chukchi Sea into the Arctic Ocean
Relationships between two Pseudoalteromonas strains isolated from the Canada Basin and the Southern Ocean using a polyphasic approach
Get PDFThe evolutionary relationships and taxonomic position of two marine planktonic bacterial strains BSw20211 and BSw10014, isolated from the Canada Basin and from the Southern Ocean, respectively, were determined using a polyphasic taxonomic approach. There was a close phylogenetic relationship between the two strains and most phenotypic properties were shared. Nonetheless, they were found to belong to different species of the genus Pseudoalteromonas on the basis of genotypic analyses. Findings were consistent with the suggestion that gyrB gene sequence comparison and DNA-DNA relatedness might better define phylogenetic relationships of bacteria at the species level. However, a cut-off value of 90% gyrB gene sequence similarity was not reliable for the differentiation of species within the genus Pseudoalteromonas
Cold-adaptive alkaline protease from the psychrophilic Planomicrobium sp. 547: enzyme characterization and gene cloning
Get PDFA psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA analysis. The optimal and highest growth temperatures for strain 547 were 15℃ and 30℃, respectively. The extracellular protease was purified by ammonium sulfate precipitation and DEAE cellulose-52 chromatography. The optimal temperature and pH for the activity of the purified enzyme were 35℃ and pH 9.0, respectively. The enzyme retained approximately 40% of its activity after 2 h of incubation at 50℃. The enzymatic activity was inhibited by 1 mmol/L phenylmethyl sulfonylfluoride (PMSF) and hydrochloride 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), indicating that it was a serine protease. The presence of Ca2+ and Mn2+ increased the activity of the enzyme. The protease gene with a size of 1 269 bp was cloned from Planomicrobium sp. 547 using primers designed based on the conserved sequences of proteases in GenBank. The Planomicrobium sp. 547 protease contained a domain belonging to the peptidase S8 family, which has a length of 309 amino acid (AA) residues. The alignment and phylogenetic analysis of the AA sequence indicated that the protease belonged to the subtilisin family
Arctic Shipping Development Prospects Evaluation: Nuclear Icebreaker Fleet in the Northern Sea Route.
No full textYoung researcher Dr.Tatiana Khomiakova, Academy of National Economy, Russia, talks here in the NRF 6th open assembly in Hveragerði, Iceland, in September of 2011.
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Social adaptation of the indigenous peoples of the Russian North to the changing ice environment.
No full textDr. Ludmila Gashiliva Head of the Institute of the Peoples of the North, and Tatiana Bulgakova, Professor of the Institute of the Peoples of the North, Russian State Pedagogical University, at the NRF 6th open Assembly in Hveragerði, Iceland. September 2011
The Quaternary glacial history of Banks Island, NWT: how the paleo-record can help us predict future glacier change.
No full textJessica Vaughan, University of Alberta, Canada, at the NRF 6th open Assembly in Hveragerði, Iceland. September 2011
The "State" of the Arctic
Get PDFProfessor Matthias Finger, EPFL - the Ecole Polytechnique Fédérale de Lausanne, Switzerland, at the NRF 6th open Assembly in Hveragerði, Iceland. September 2011
Sovereignty as a Social Issue: The case of Inuit Nunangat.
No full textMark Vardy, Queen’s University, Canada, at the NRF 6th open Assembly in Hveragerði, Iceland. September 2011
AlaskaDispatch.com
No full textAlice Rogoff from AlaskaDispatch.com, at the NRF 6th open Assembly in Hveragerði, Iceland. September 2011
Arctic Ice-edge Map
No full textThe maps shows the median ice-edge in the Arctic in april and september from 1979 to 2000. It also displays the ice deposit in 2006. 2007, 2010 and 2011. The data source is National Snow and Ice Data Centre