TITLE: 2002-JOSSBe7-SedChl P.I.(S): Lee Cooper, Jackie Grebmeier 10515 Research Dr. Suite 100, Bldg. A Marine Biochemistry & Ecology Dept. of Ecology & Evolutionary Biology University of Tennessee, Knoxville Knoxville, TN 37932 tel: +1 865.974.2990 fax: +1 865.974.7896 email: lcooper1@utk.edu website: http://arctic.bio.utk.edu FUNDING SOURCE/GRANT NUMBER: NSF OPP0125082 NSF OPP9910319 DATASET OVERVIEW: This dataset contains measurements of a short-lived gamma emitter, beryllium-7 (half-life 53 d) obtained from surface (0-1 cm) sediment samples collected at depths ranging from 50-3000m, as well as melted snow present on the sea ice surface. Samples included in this dataset were collected from May 11 - June 6, 2002, and July 19 - August 21, 2002 from the United States Coast Guard Icebreaker Healy (WAGB-20). During the second Healy cruise, the precipitation flux was measured using two on-board precipitation collectors onboard the ship. Some additional sediment samples were collected on the Canadian Coast Guard Service Sir Wilfrid Laurier in July 2002. Samples collected on the Healy were funded through the Shelf-Basin Interactions project, which is funded by both the National Science Foundation and the Office of Naval Research. The Bering Strait Long-Term Observatory program, with funding provided by the National Science Foundation supported sediment collections from the Sir Wilfrid Laurier. Other gamma emitter data was generated, including cesium-137 and potassium-40. These data are not tabulated here, but may be added later following quality assurance. Alternately, these data can be made available upon request to the principal investigator. INSTRUMENT DESCRIPTION: Two devices were used for sample collection. A van Veen grab (0.1 m2 sediment grab), weighted with 32 kg of lead was used in the collection of surface sediment samples that were put in a 0.5L Marinelli beaker (plastic beaker with a well in the bottom for insertion over a gamma detector). A multi (4 barrel) Haps corer (each core = 0.0133 m2) was used to collect sediment cores , which were later sectioned, canned, and frozen. For more information on the HAPS core, see: Kanneworff, E. & Nicolaisen, W. The "HAPS:" A frame supported bottom corer. Ophelia Supplement 10, 119-129 (1973). Radioassays were accomplished as follows: Snow samples (625 cm2) were collected from the surface of sea ice during the early season research cruise (May-June 2003) prior to any significant melt (H. Eicken, personal communication). Care was taken to collect all snow present above the sea ice surface. Snow was brought aboard ship, melted and shipped to the University of Tennessee for gamma spectroscopy. All counting was completed within three months of collection (~2 half-lives). Prior to counting, liquid (snow) samples were concentrated by heating; weak acid (5% HCl) was used to keep 7Be in solution and prevent adherence to container walls. Sediments were directly counted without further processing. Gamma spectroscopy was performed using a Canberra GR4020/S reverse electrode closed-end coaxial detector. 7Be was detected by gamma decay at 477.6 KeV, using Canberra Genie 2000 software, which included corrections for efficiency and calibration with standards traceable to the U.S. National Institute of Science and Technology. Sediments were sectioned to depths of up to 15 cm, although no 7Be was detected below the 1 cm increment in any sample. 90 cm3 of each one-cm sediment increment was added to aluminium cans with calibrated geometries for direct counting, using the gamma spectroscopy system. When 7Be was not detected in the 90 cm3 0-1 cm increment, a 1 L sample of surface sediments from the same location, collected using a 0.25 m2 van Veen grab was counted, using 0.5 or 1 L Marinelli beakers with calibrated geometries. Since the van Veen grab penetrates to variable depths, and does not return undisturbed surface sediments to the surface, it was not possible to accurately quantify the inventory of 7Be measured in these samples on a square meter basis. When 7Be was detected in Marinelli beakers, but not in the 90-cm3 cans collected at the same location, these data are indicated as having had a trace of 7Be detected and activities are indicated in Bq g dry weight-1. Samples for determination of chlorophyll a in surface (0-1 cm) sediments were also collected from the top 0-1 cm of the multi-HAPS cores. Following dark storage for 12 hr in 90% acetone, chlorophyll a concentrations associated with small surface area aliquots of sediments were determined fluorometrically. These methods are described in more detail in: Cooper et al. 2002, Marine Ecology Progress Series 226: 13-26. DATA FORMAT File Names (Formats): HLY0201-JOSSBe7.txt (Tab delimited text file) HLY0201-JOSSBe7.xls (MS XL 5.0/95 file) NOTE: all of our Excel files will be saved in 5.0/95 version, so that everyone will have access to it. Naming Convention: CruiseName-"JOSS"Variable.filetype (ex. HLY0201-JOSSO-18.txt) Data Format and Layout: Ship - HLY: "Healy", USCG Icebreaker WAGB-20 SWL: Sir Wilfrid Laurier, Canadian Coast Guard Service Year - 02 : year, 2002 Cruise# - 01 : cruise number for the ship for that year Station# - sequentially numbered from beginning to end of cruise Station Name - based on transect names, the lower the number the less the depth HV : Herald Valley WHS : West Hanna Shoal EHS : East Hanna Shoal BC : Barrow Canyon EB : East Barrow ICE : refers to a station where a snowmelt sample was collected Event# - coincides with the event numbers listed on JOSS' website Lat., Long., Date/Time - self-explanatory Depth - bottom depth in meters Geometry - refers to the container geometry Can : surf. area = 90 sq cm MB : s.a. = n/a, activity is on a per gram dry wt basis Core Depth - depth of the core section below the surface of the sediment, in cm. Area - surface area from where the sample was collected Be-7 activity Activity plus/minus standard error Sediment chlorophyll in mg m2v=sediment chlorophyll collected from surface sediments of van Veen grab before the grab was opened; h=sediment chlorophyll collected from surface sediments (0-1 cm) of HAPS core. Some additional data will be eventually available including comparisons in sediment chlorophyll concencentrations, such as samples collected with both the van Veen grab and HAPS core at the same stations. Data Version Number and Date: Version 1, 5/30/03 Software Compatibility: This dataset will be posted in both Microsoft Excel 5.0/95 and as a tab-delimited text file.