snyder_iodinesed English utf8 dataset McMurdo Dry Valleys LTER http://mcmlter.org/ 2014-11-04 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Iodine content and I-129 isotopic composition in McMurdo lake-bottom sediments 2014-11-04 publication Glen Snyder Rice http://www.rice.edu/ (713) 348-4054 Earth Science-MS 126 Houston TX 77251 US gsnyder@rice.edu pointOfContact W. Berry Lyons The Ohio State University https://www.osu.edu/ (614) 688-3241 275 Mendenhall Lab Columbus OH 43210 US lyons.142@osu.edu http://research.bpcrc.osu.edu/EnvironmentalGeochemistry/ pointOfContact documentDigital As part of a collaborative investigation between researchers at Rice University, Arkansas State University, University of Rochester, and Ohio State University, lakes of the McMurdo Dry Valleys were sampled at discreet depth intervals during the 2005-2006 field season.  Sample splits were subsequently analyzed for chemical and isotopic composition of both gases and dissolved  ions, as well as dissolved organic carbon. In addition, cryogenic salts were sampled in the surrounding lake shores in order to determine the salt sources. Gravity cores were also obtained and the pore waters were collected by centrifuging the wet sediment.    Presented  in this file is the total iodine content and I-129 isotopic composition of lake-bottom sediments from Lakes Joyce and Fryxell. An attempt was made to determine the  iodine and chlorine isotopic content  of gypsum cored from the bottom of Lake Vanda, but the total iodine content was below detection.              Name: Chris Gardner Role: data manager Name: Inigo San Gil Role: data manager completed McMurdo Dry Valleys LTER http://mcmlter.org/ unknown This dataset was created Oct 1, 2008 by MCM-LTER information manager (Chris Gardner) after email discussion with PI Glen Snyder.   In 2014, this metadata was enhanced using the Drupal Ecological Information Management System (Inigo San Gil)   Metadata completed in 2016 inorganic nutrients theme LTER Core Areas English The Lake Fryxell basin is formed by a moraine depression in a wider portion of the Taylor Valley. It has a number of moraine islands and shallower areas, as well as several relatively well developed deltas. The lake is fed by at least 10 meltwater streams with a total drainage catchment of 230 km2. The lake is dammed to the southwest by the Canada Glacier and is topographically closed. It is perennially ice covered; during summer months, an ice-free moat generally forms around much of the lake margin. Lake levels have risen ~2 m between 1971 and 1996. There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 9 Maximum Length (km): 5.8 Maximum Width (km): 2.1 Maximum Depth (m): 20 Surface Area (km^2): 7.08 Ice Thickness Average Surface (m): 3.3 - 4.5 Volume (m^3 * 10^6): 25.2 163.259582519531 163.048782348633 -77.622711181641 -77.597076416016 Lake Joyce lies in the Pearse Valley against the Taylor Glacier.  Valley: Pearse  Distance to Sea : 44  Maximum Length (km): 1  Maximum Width (km): 1  Maximum Depth (m): 35  Surface Area (km^2): 0.83  Ice Thickness Average Surface (m): 3.9 - 5.6  Volume (m^3 * 10^6): 4.9 161.662445068359 161.608886718750 -77.726486206055 -77.715972900391 ground condition 2005-12-21 2005-12-27 FUNDING: This material is based upon work supported by the National Science Foundation under Grant No.0440686 https://mcm.lternet.edu/sites/default/files/ANCILLARY_SNYDER_IODINESED.csv ANCILLARY_SNYDER_IODINESED eng; US McMurdo Dry Valleys LTER ANCILLARY_SNYDER_IODINESED Data Source Definition : This is the description of the spreadsheet fo the iodine study, with columns description and units used Record Delimiter : \n Number of Header Lines : 27 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Table Identifier LOCATION_NAME Name of lake where measurement was made Location_Type Sample type description and/or location Sample_ID Sample identification code Latitude Sample Latitude Longitude Sample Longitude Date_time Date sample was collected Date Time Format: mm/dd/yyyy Depth (m) Average sediment depth in centimeters below the lake floo I(umol/kg) Total sedimentary iodine content in micromoles per kilogram I(umol/kg) Total dissolved iodine in micromoles per kilogram 129I/I(E-15) Molar ratio of I-129 to total iodine (10^-15) +/-129I/I(E-15) 1-sigma error in molar ratios of I-129/I-127 (10^-15) 129I(at/uL) Concentration of I-129 in atoms per microliter +/-129I(at/uL) 1-sigma error for I-129 concentration DBF https://mcm.lternet.edu/sites/default/files/ANCILLARY_SNYDER_IODINESED.csv dataset Waters were sampled by first drilling through the ice and then lowering a Go-Flo bottle to the indicated depths. Retrieved samples were then spit into separate containers for analysis. Following the sampling of water, a shallow gravity corer with plastic lining was  attached to steel cable  and lowered through the ice hole and down to the lake bottom. The corer was dropped the final 3 meters. Core recovery ranged from only a few centimeters to 25 centimeters. Once recovered, the sediments were stoppered and transported vertically to Crary Laboratory at McMurdo station. Sediment was separated along several intervals of each core and sediment and pore waters were separated by centrifugation.     Sediment samples were shipped to Rice University where they were freeze dried and then powdered. Iodine was volatilized from the samples using a pyrohydrolysis apparatus at 900 degrees Celsius, and the vapors were trapped in a solution of tetramethylammonium hydroxide. The trapped iodine was diluted then analyzed for stable I-127 at the ICP-MS facility of Cin-Ty Lee at Rice University. Methods for analysis are described in: Schnetger, B., and Muramatsu, Y., Determination of the halogens, with special reference to iodine, in geological and biological samples using pyrohydrolysis for preparation of inductively coupled plasma mass spectrometry and ion chromatography for measurement, Analyst, 121:1627-1631.                      Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact