Entry_ID: (required) Entry_Title: Pacific Arctic Stable Isotope Synthesis Group: Data_Set_Citation Originator(s): Ken Dunton, Marine Science Institute, The University of Texas at Austin, Professor Title: Pacific Arctic Stable Isotope Synthesis Publication_Date: 20130227 Publisher: Earth Observing Laboratory Data_Presentation_Form: vector digital data URL: pacmars.eol.ucar.edu End_Group Keyword: biota Keyword: environment Keyword: geoscientificInformation Keyword: oceans Group: Temporal_Coverage Start_date: 19800101 Stop_date: 20100810 End_Group Group: Spatial_Coverage Southernmost_Latitude: 57.882074 Northernmost_Latitude: 79.144987 Westernmost_Longitude: -180.000000 Easternmost_Longitude: 180.000000 End_Group Location: Arctic Ocean Group: Data_Resolution Latitude_Resolution: 0.000000006783107409091829 Longitude_Resolution: 0.000000006783107409091829 End_Group Access_Constraints: Station locations are publicly available. Stable isotope values are restricted for use within the PacMARS research team. Data will be made available to the public after the first year of the PacMARS project. The publisher, originator, original data collectors, and others associated with this work assume no liability for the quality and use of this dataset. Use_Constraints: PacMARS team members should be contacted before use of their data sets. PacMARS investigators and others are responsible for providing appropriate recognition to data providers in publications. This can include article co-authorship and/or reference to data publications. Citations, and DOIs when available, will be provided for datasets within the EOL data archive. Originating_Center: (required) Group: Data_Center Data_Center_Name: National Center for Atmospheric Research Group: Data_Center_Contact Last_name: Laboratory First_name: Earth Middle_name: Observing Email: codiac@ucar.edu Email: stott@ucar.edu Phone: 303-497-8154 Group: Address 3450 Mitchell Lane Boulder, CO 80301 USA End_Group End_Group End_Group Storage_Medium: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.1.1.3143 Group: Reference End_Group Group: Summary To synthesize carbon and nitrogen stable isotope data from several studies into a single dataset, with a focus on data in the Pacific-influenced coastal shelf ecosystem of the Arctic Ocean. This dataset is a synthesis of carbon and nitrogen stable isotope data from several studies collected into a single GIS feature class. The data cover the Pacific-influenced coastal shelf ecosystem of the Arctic Ocean. Data points include isotopic ratios of del C-13 and del N-15. Additional metadata such as the names of the original data collectors are included as attributes of the feature class when available. Carbon isotope ratios are a good indicator of carbon sources of the food web because of their small enrichment steps between consecutive consumers (0-1‰) and nitrogen isotope ratios are good indicators of trophic level (TL) because of the larger enrichment step of 3-4‰ between TL. This dataset was compiled from various other studies performed throughout several decades in the Arctic Ocean. Data were compiled in spreadsheet form and then imported into GIS as a single feature class. Data source information is provided as attributes for each data point. (null) Benthic samples for stable isotopic measurements (13C and 15N) were obtained from both van Veen grabs and benthic trawls. Zooplankton and samples of particulate organic matter (POM) were also collected for isotopic analysis; these data were used to develop our coupled benthic-pelagic conceptual food web model. In addition to biota, replicate 1 cc surface samples of undisturbed sediment were frozen for sediment isotopic analysis. Prior to 2002, sub-samples of freeze-dried tissue for isotopic analysis were treated with dilute HCl for several hours to remove carbonates and then dried at 70oC. About 15-20 mg of dried tissue samples were ground with 1 g of CuO and combusted in evacuated quartz tubes. The liberated carbon dioxide and nitrogen were cryogenically cleaned and stored in sealed glass tubes until analysis. Mass spectrometry was conducted using a VG Isogas SIRA 9 Mass Spectrometer. Machine precision was approximately ±0/2% for δ13C and ±0.3% for δ15N. Results are expressed in standard δ notation relative to carbonate PeeDeeBelemnite and atmospheric nitrogen where: (null) δ 13C or δ 15N (‰) = [Rsample/Rstandard) – 1] x 1000 (null) and R = (13C/12C or 15N/14N), respectively. (null) After 2002, tissues for isotope analyses were processed on an easier and more accurate system. All biota were dried in aluminum dishes at 60 °C following removal of extraneous organic matter. When possible, soft tissues were removed from shelled organisms. All invertebrate samples were soaked in 1 N HCl for several hours to remove carbonates, rinsed in distilled water, and then dried. Muscle or body wall tissue was analyzed from bivalves, gastropods, large crustaceans (euphausiids and amphipods), and fish; all other organisms were analyzed whole. Entire organisms or tissues are manually ground for isotopic analyses. Replicate analyses reflected the analysis of individual organisms, not composite samples. All samples were analyzed on an automated system for coupled δ 13C and δ 15N measurements using a Finnegan MAT Delta Plus mass spectrometer attached to an elemental analyzer (CE Instruments, NC 2500). Samples were combusted at 1,020 °C and then injected into the mass spectrometer with continuous flow. Results are expressed in standard δ notation as seen above. Secondary and NBS calibration standards were routinely for cross-calibration checks of tank reference gases, against which all samples are run. The resulting data were reproducible to within ± 0.2 ‰. Machine analytical error was ± 0.15 ‰. End_Group Group: DIF_Author Last_name: Whiteaker First_name: Tim Email: twhit@mail.utexas.edu Phone: 512-471-0570 Group: Address 10100 Burnet Rd., Bldg. 119 Austin, TX 78758 USA End_Group End_Group DIF_Revision_Date: 20130529 Science_Review_Date: