VG_DESORP English utf8 dataset McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact 2021-03-25 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Ammonium desorption of hyporheic sediments from Von Guerard Stream, McMurdo Dry Valleys, Antarctica (January 2019) 2021-03-25 publication Joel Singley University of Colorado Boulder http://www.colorado.edu/ Institute of Arctic and Alpine Research Boulder CO 80303 US joel.singley@colorado.edu pointOfContact Michael Gooseff University of Colorado Boulder http://www.colorado.edu/ michael.gooseff@colorado.edu http://goosefflab.weebly.com pointOfContact Eve-Lyn Hinckley University of Colorado Boulder http://www.colorado.edu/ eve.hinckley@colorado.edu pointOfContact documentDigital This data package provides analytic results for a laboratory assay on sediment samples collected in January 2019 from a transect (“P2”) across Von Guerard Stream (as described by Heindel et al. 2021), located in Taylor Valley, McMurdo Dry Valleys, Antarctica. We used excess sample from that study in a laboratory desorption assay to assess conductivity dependent desorption of ammonium. The assay was performed by mixing samples with potassium chloride treatment solutions that replicate the range of specific conductivities observed in Von Guerard Stream, shaking and centrifuging slurries, and analyzing filtered supernatant.  Name: Renée F. Brown Role: data manager completed McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact inorganic nutrients theme LTER Core Areas English Transect type is "pool." Coordinates provided by Ruth Heindel on 24 September 2020. 163.289283000000 163.289283000000 -77.619583000000 -77.619583000000 2019-01-10 https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vg_desorp-20210325.csv VG_DESORP eng; US McMurdo Dry Valleys LTER VG_DESORP Data Source Definition : This data table provides sediment sample information and concentrations of analytes for extraction solution blanks and sample aliquots. Data are organized by sampling location and treatment. Number of Header Lines : 1 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Internal dataset code representing Von Guerard sediment desorption assay. STRMGAGEID Code representing stream gage station. STREAM_NAME Name of stream. SAMPLE_ID Alphanumeric code indicating lateral location of sample on transect, treatment, and replicate id. 1-5 = lateral location from wetted margin on stream left to wetted margin on stream right, with 3 at the thalweg; 0,40,80,160,320 indicate treatment solution conductivity; A-C indicate replicate identifier. SAMPLE_TYPE Alphanumeric code identifying sample type. Sample = treated sediment sample; solution_blank = treatment solution without sediment. LATERAL_POSITION Sample location identifier from lateral transect across stream. 1-5 = lateral location from wetted margin on stream left to wetted margin on stream right, with 3 at the thalweg. SC_US_CM Actual specific conductivity of treatment solution WET_SED_MASS_G Initial sediment mass under field moisture conditions. VWC Volumetric water content in decimal percent. DRY_SED_MASS_G Estimated dry sediment mass based on WET_SED_MASS_g and VWC. SOL_VOL Treatment solution volume added to sample. K_MGL Concentration of potassium. See COMMENTS for details regarding blank cells. ND = not detected, NM = not measured. CL_MGL Concentration of chloride. See COMMENTS for details regarding blank cells. ND = not detected, NM = not measured. NH4_MGL Concentration of nitrogen as ammonium. See COMMENTS for details regarding blank cells. ND = not detected, NM = not measured. NH4_UG_G_DRY_SED Normalized mass of nitrogen as ammonium per gram of dry sediment. See COMMENTS for details regarding blank cells. ND = not detected, NM = not measured. NO3_MGL Concentration of nitrogen as nitrate plus nitrite. See COMMENTS for details regarding blank cells. ND = not detected, NM = not measured. NO3_UG_G_DRY_SED Normalized mass of nitrogen as nitrate plus nitrite per gram of dry sediment. See COMMENTS for details regarding blank cells. ND = not detected, NM = not measured. COMMENTS Comments regarding blank cells. DBF https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vg_desorp-20210325.csv dataset Samples were collected in the lower reaches of Von Guerard stream in January 2019 along a transect P2 as reported by Heindel et al. 2021. Sediment sampling methods, metadata, and information regarding total extractable ammonium and additional ancillary data are also reported by Heindel et al. 2021. We utilized subsamples from the P2 (pool morphology) transect. Wet sediment subsamples were weighed in triplicate for each sampling location (1-5) into sterile 250 mL HDPE wide mouth bottles and kept frozen (-20 ºC) prior to running the assay. For the assay, we prepared five solutions of varying conductivities using potassium chloride. The specific conductivity of each treatment solution was measured using a benchtop probe and a three or four point calibration. Sediment samples were removed from the freezer and treatment solution was added to each bottle to achieve a 2:5 sediment:solution ratio by mass. Bottles were inverted three times and placed on a shaker table at 300 rpm for 1 hour. Slurries were centrifuged at 3000 rpm for 5 minutes and then the supernatant was filtered through glass fiber filters (GF/F) and stored frozen prior to analysis. Supernatant aliquots were analyzed by the Arikaree Environmental Laboratory at the University of Colorado Boulder. Potassium was measured by Method EPA 7000B on a Perkin Elmer Model AAnalyst 200 Atomic Absorption Spectrometer with a limit of detection of 0.004 mg K+ per liter. Chloride was measured by Method EPA 300.1 on a Metrohm 930 Compact IC Flex with a limit of detection of 0.03 mg Cl- per liter. Nitrogen as ammonium measured by Method 10-107-06-1-A on a Lachat Quickchem Flow Injection Autoanalyzer with a limit of detection of 0.005 mg N per liter. Nitrogen as nitrate plus nitrite measured by Methods 10-107-04-1-A and 10-117-07-1-B on a Lachat Quickchem Flow Injection Autoanalyzer with a limit of detection of 0.002 mg N per liter. Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact