52 resultados para 2-DIMENSIONAL ELECTRON-SYSTEM


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DNA extraction was carried out as described on the MICROBIS project pages (http://icomm.mbl.edu/microbis ) using a commercially available extraction kit. We amplified the hypervariable regions V4-V6 of archaeal and bacterial 16S rRNA genes using PCR and several sets of forward and reverse primers (http://vamps.mbl.edu/resources/primers.php). Massively parallel tag sequencing of the PCR products was carried out on a 454 Life Sciences GS FLX sequencer at Marine Biological Laboratory, Woods Hole, MA, following the same experimental conditions for all samples. Sequence reads were submitted to a rigorous quality control procedure based on mothur v30 (doi:10.1128/AEM.01541-09) including denoising of the flow grams using an algorithm based on PyroNoise (doi:10.1038/nmeth.1361), removal of PCR errors and a chimera check using uchime (doi:10.1093/bioinformatics/btr381). The reads were taxonomically assigned according to the SILVA taxonomy (SSURef v119, 07-2014; doi:10.1093/nar/gks1219) implemented in mothur and clustered at 98% ribosomal RNA gene V4-V6 sequence identity. V4-V6 amplicon sequence abundance tables were standardized to account for unequal sampling effort using 1000 (Archaea) and 2300 (Bacteria) randomly chosen sequences without replacement using mothur and then used to calculate inverse Simpson diversity indices and Chao1 richness (doi:10.2307/4615964). Bray-Curtis dissimilarities (doi:10.2307/1942268) between all samples were calculated and used for 2-dimensional non metric multidimensional scaling (NMDS) ordinations with 20 random starts (doi:10.1007/BF02289694). Stress values below 0.2 indicated that the multidimensional dataset was well represented by the 2D ordination. NMDS ordinations were compared and tested using Procrustes correlation analysis (doi:10.1007/BF02291478). All analyses were carried out with the R statistical environment and the packages vegan (available at: http://cran.r-project.org/package=vegan), labdsv (available at: http://cran.r-project.org/package=labdsv), as well as with custom R scripts. Operational taxonomic units at 98% sequence identity (OTU0.03) that occurred only once in the whole dataset were termed absolute single sequence OTUs (SSOabs; doi:10.1038/ismej.2011.132). OTU0.03 sequences that occurred only once in at least one sample, but may occur more often in other samples were termed relative single sequence OTUs (SSOrel). SSOrel are particularly interesting for community ecology, since they comprise rare organisms that might become abundant when conditions change.16S rRNA amplicons and metagenomic reads have been stored in the sequence read archive under SRA project accession number SRP042162.

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Multibeam data were measured as part of the project HERMES during R/V Polarstern cruise ARK-XXII/1 (2007-05-29 to 2007-07-25) along transits and survey profiles and partly during stationary work. Data were achieved mainly in the coastal areas of northern Norway, at the Hakon Mosby Mud Volcano at the continental margin approx. 200 nm off the norwegian coast and the AWI-Hausgarten area approx. 150 nm west of Svalbard. A number of surveys were carried out in the coastal areas of northern Norway (Sula Reef, Roest Reef, Traena area, Floholmen area, Sotbakken area) and around the area of the Hakon Mosby Mud Volcano. The multibeam sonar system Atlas Hydrosweep DS-2 (Atlas Hydrographic, http://www.atlashydro.com) was operated using 59 beams and 90° aperture angle. The refraction correction was achieved using CTD profiles measured during this cruise or, during transits, utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions (only in the AWI-Hausgarten area). This dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were measured as part of the project HERMES during R/V Polarstern cruise ARK-XXII/1 (2007-05-29 to 2007-07-25) along transits and survey profiles and partly during stationary work. Data were achieved mainly in the coastal areas of northern Norway, at the Hakon Mosby Mud Volcano at the continental margin approx. 200 nm off the norwegian coast and the AWI-Hausgarten area approx. 150 nm west of Svalbard. A number of surveys were carried out in the coastal areas of northern Norway (Sula Reef, Roest Reef, Traena area, Floholmen area, Sotbakken area) and around the area of the Hakon Mosby Mud Volcano. The multibeam sonar system Atlas Hydrosweep DS-2 (Atlas Hydrographic, http://www.atlashydro.com) was operated using 59 beams and 90° aperture angle. The refraction correction was achieved using CTD profiles measured during this cruise or, during transits, utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions (only in the AWI-Hausgarten area). This dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were measured during R/V Polarstern cruise ANT-XIX/5 along track lines of approximately 4000 NM total length in the Scotia Sea. Data were achieved along the Scotia Arc from Burdwood Bank to King George Island. A multibeam box survey was conducted at the southern part of the Discovery Rise, located at 50°55'S / 35°30'W and covering an area of 90 x 15 NM. A bathymetric survey of 25 x 60 NM was carried out at the eastern part of the South Shetland Trench and its intersection with the Shackleton Fracture Zone, continuing multibeam data from former expeditions. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The refraction correction was achieved utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were measured during R/V Polarstern cruise ARK-XXIII/3 along track lines of 7248 NM total length in the Arctic Ocean during transits and stationary work. Data were achieved on the transit from Iceland through the Northwestern Passage and the Beaufort Sea to the East Siberian Sea, crossing Northwind Ridge and Chukchi Plateau. The continental margin of East Siberian was surveyed by several wide spaced transects for almost three weeks. The Mendeleev Ridge and the surrounding deep sea bassins were investigated by a transect of about 1000 NM length, located at 80°-81°N. Lomonosov Ridge and Gakkel Ridge were also crossed. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle, 120° in shallow water areas. The refraction correction was achieved utilizing 14 CTD profiles measured during the cruise or by the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were collected without operator supervision on R/V Polarstern cruise ANT-XV/3 during 19 days along track lines of about 1100 NM total length. Data were achieved during transits and stationary work in the eastern Weddell Sea off the Riiser-Larsen Ice Shelf between Halley Bay and Atka Bay. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were collected without operator supervision on R/V Polarstern cruise ANT-XVI/3 along track lines of approximately 6700 NM. Data were achieved during transits and stationary work in the Weddell Sea off the Ekstrom Ice Shelf and the Jelbart Ice Shelf and in the South Atlantic Ocean. An area of 140 x 140 km was surveyed with 15 km transect space at about 49.5°S and 20°E. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were measured during R/V Polarstern cruise ANT-XXII/3 along track lines of approximately 8000 NM total length during transits and partly during stationary work. Data were achieved on a transect along the Greenwich meridian, across the Weddell Sea from Kapp Norvegia to Joinville Island, across the Powell Basin, furthermore in the Drake Passage and west of Antarctic Peninsula. Short bathymetric surveys were carried out on the continental slope off Kapp Norvegia and Fimbulisen, and in the area of the Weddell Abyssal Plain. The multibeam sonar system Hydrosweep DS-2 was operated mainly in the HDBE softbeam mode with 240 depth values per swath and a receiving coverage of 100°. The refraction correction was achieved utilizing CTD profiles or the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

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Multibeam data were measured during R/V Polarstern cruise ANT-XIX/1 on track lines of about 5,200 NM total length in the Atlantic Ocean during the transit from Bremerhaven to Cape Town. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The refraction correction was achieved utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.