Glen SnyderW. Berry Lyons 2014-11-04 tabular digitial data McMurdo Dry Valleys LTER McMurdo Dry Valleys LTER 10.6073/pasta/9f0a7a162d54f9db5113426eb2ccd0c3 https://mcm.lternet.edu/content/iodine-content-and-i-129-isotopic-composition-mcmurdo-lake-bottom-sediments 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.             FUNDING: This material is based upon work supported by the National Science Foundation under Grant No.0440686 2005-12-21 2005-12-27 ground condition 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 As needed 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 -77.597076416016 -77.622711181641 18m 18m meter 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 -77.715972900391 -77.726486206055 301m 301m meter LTER Core Areas inorganic nutrients None <cntorg>McMurdo Dry Valleys LTER</cntorg> <onlink>http://mcmlter.org/</onlink> <span property="dc:title" content="McMurdo Dry Valleys LTER" class="rdf-meta element-hidden"></span> Name: Chris Gardner Role: data manager Name: Inigo San Gil Role: data manager Not Applicable Not Applicable Field and/or Lab Methods 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.                      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.                     unknown ANCILLARY_SNYDER_IODINESED This is the description of the spreadsheet fo the iodine study, with columns description and units used DATASET_CODE Table Identifier The data provider Table Identifier Location Name Name of lake where measurement was made The data provider Name of lake where measurement was made Location_Type Sample type description and/or location The data provider Sample type description and/or location Sample_ID Sample identification code The data provider Sample identification code Latitude Sample Latitude The data provider degree Longitude Sample Longitude The data provider degree Date_time Date sample was collected The data provider calendar date/time mm/dd/yyyy gregorian calendar Depth (m) Average sediment depth in centimeters below the lake floo The data provider centimeter I(umol/kg) Total sedimentary iodine content in micromoles per kilogram The data provider 2.32 545 umol/kg I(umol/kg) Total dissolved iodine in micromoles per kilogram The data provider 0.004 8.109 umol/kg 129I/I(E-15) Molar ratio of I-129 to total iodine (10^-15) The data provider 216 12929 dimensionless +/-129I/I(E-15) 1-sigma error in molar ratios of I-129/I-127 (10^-15) The data provider 49.02 3454 dimensionless 129I(at/uL) Concentration of I-129 in atoms per microliter The data provider 0.39 142.7 at/uL +/-129I(at/uL) 1-sigma error for I-129 concentration The data provider 0.09 38.07 dimensionless McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 \n 27 column , https://mcm.lternet.edu/sites/default/files/ANCILLARY_SNYDER_IODINESED.csv None 2014-11-04 2014-11-04 McMurdo Dry Valleys LTER http://mcmlter.org/ Biological Data Profile of the Content Standards for Digital Geospatial Metadata devised by the Federal Geographic Data Committee. Drupal Ecological information Management Systems, version D7, Biological Data Profile module