VGPW English utf8 dataset McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact 2020-07-09 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Surface and hyporheic porewater chemistry and sediment nitrification potentials in Von Guerard Stream, McMurdo Dry Valleys, Antarctica (2018-2020) 2020-07-09 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 Diane McKnight University of Colorado Boulder http://www.colorado.edu/ diane.mcknight@colorado.edu pointOfContact Eve-Lyn Hinckley University of Colorado Boulder http://www.colorado.edu/ eve.hinckley@colorado.edu pointOfContact documentDigital Surface water and hyporheic porewater samples were collected at high frequency during the 2017-18 (01/20/2018-01/21/2018) and 2018-19 (01/10/2019-01/12/2019) flow seasons, and opportunistically throughout the 2019-20 flow season (12/17/2019-1/25/2020) from the lower reaches of Von Guerard Stream, Taylor Valley, McMurdo Dry Valleys, Antarctica. Porewater samples were collected using plastic tubing inserted to depths of 15 or 30 cm and drawn out by syringe. This data package includes sampling locations and water chemistry data (including concentrations for dissolved organic nitrogen species, dissolved organic carbon, silica, as well as water isotopes). A laboratory nitrification potential assay was performed on sediments collected from Von Guerard stream during the 2017-18 flow season to assess the functional microbial potential of the hyporheic microbial community to perform nitrification.  Name: Kathleen A. Welch Role: lab technician Name: Anna J. Bergstrom Role: lab technician 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 USGS site 5; coordinates taken from 1996-97 GPS measurements at center of weir Parent Stream: Von Guerard Stream Provenance : GPS96-97.DOC ID: vguerard_f6 163.253997802734 163.253997802734 -77.608200073242 -77.608200073242 ground condition 2018-01-20 2020-01-25 https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-chemistry-20210325.csv VGPW_CHEM eng; US McMurdo Dry Valleys LTER VGPW_CHEM Data Source Definition : Water chemistry data for concurrent surface and porewater samples, organized by sampling location, sampling time, and solute (DIN species, DOC, and water isotopes). Number of Header Lines : 1 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Internal dataset code. STRMGAGEID Stream Gage ID. STREAM_NAME Name of the stream. SAMPLE_ID Alphanumeric code indicating sample year and sequential number. DATE_TIME Date and time of sample collection (MM/DD/YYYY HH:MM UTC+13). Date Time Format: MM/DD/YYYY HH:MM UTC+13 SAMPLE_TYPE Type of sample. surface surface water pore hyporheic porewater SAMPLE_YEAR Year of sample collection. Date Time Format: YYYY TRANSECT Alphanumeric code identifying longitudinal transect, numbered from upstream to downstream. Transect locations shifted among years as noted in the associated data table ‘VGPW_LOCATIONS’. T1 = Transect 1, and so on. SITE Letter identifying the lateral location on the transect. Values for lateral porewater sites are A-D with A at the channel center and D the wetted margin. SW indicates surface water. DEPTH_CM For pore samples, indicates the depth of sampler intake below streambed surface, where 0 = surface water, 15 = 15 cm, and 30 = 30 cm. N_NO3_MGL Concentration of nitrogen as nitrate + nitrite in milligrams of nitrogen per liter. N_NO3_COMMENTS Comments regarding nitrate concentrations, where ND = not detected and NM = not measured. N_NH4_MGL Concentration of nitrogen as ammonium in milligrams of nitrogen per liter. N_NH4_COMMENTS Comments regarding ammonium concentrations, where ND = not detected and NM = not measured. SI_MGL Dissolved silica concentration in milligrams of silica per liter. SI_COMMENTS Comments regarding dissolved silica concentrations, where ND = not detected and NM = not measured. DOC_MGL Dissolved organic carbon concentration in milligrams of carbon per liter. DOC_COMMENTS Comments regarding dissolved organic carbon concentrations, where ND = not detected and NM = not measured. D18O_PERMIL δ18O isotope ratio reported in reported in parts per thousand (per mil, ‰). DD_PERMIL δD isotope ratio reported in reported in parts per thousand (per mil, ‰). DEXCESS Deuterium excess as calculated by δD-8*δ18O. ISOTOPE_COMMENTS Comments regarding all isotope values, where ND = not detected and NM = not measured. SC_USCM Specific conductivity in microSiemens per centimeter. SC_COMMENTS Comments regarding specific conductivity, where ND = not detected and NM = not measured. INUNDATED Identifies whether sampling location was inundated by surface water at time of sample collection. Surface water samples are noted with “Yes”. Yes Inundated No Not inundated DBF https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-chemistry-20210325.csv https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-locations-20210325.csv VGPW_LOCATIONS eng; US McMurdo Dry Valleys LTER VGPW_LOCATIONS Data Source Definition : Location information for sampling transects along Von Guerard Stream. Number of Header Lines : 1 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Internal dataset code. STRMGAGEID Stream gage ID. STREAM_NAME Name of the stream. TRANSECT Alphanumeric transect identifier, number increases from upstream to downstream. SAMPLE_YEAR Year in which sample was collected. Date Time Format: YYYY LATITUDE Sampling transect latitude. LONGITUDE Sampling transect longitude. DBF https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-locations-20210325.csv https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-nitrification-20200820.csv VGPW_NITRIFICATION eng; US McMurdo Dry Valleys LTER VGPW_NITRIFICATION Data Source Definition : Laboratory nitrification potential assay data for sediments collected from Von Guerard Stream.  Number of Header Lines : 1 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Internal dataset code. STRMGAGEID Stream Gage ID. STREAM_NAME Name of the stream. SAMPLE_ID Code indicating sediment sample location, prior to replication. SAMPLE_YEAR Year sample was collected. Date Time Format: YYYY TRANSECT Alphanumeric transect identifier, number increases from upstream to downstream. SITE Lateral site on the transect. A Center of channel C Wetted margin REPLICATE Replicate identifier within the same sampling site. ELAPSED_TIME_DAY Time (in days) since the beginning of the nitrification potential assay. N_NO2_UGL Concentration of nitrogen as nitrite in aliquot, reported in micrograms of nitrogen per liter. N_NO2_COMMENTS Comments regarding nitrate concentration, where NM = not measured. DRY_SED_G Dry mass of sediment in flask, reported as grams of sediment. VOLUME_L Volume of incubation solution in liters. N_NO2_UGKG Nitrogen as nitrate concentration normalized to dry mass sediment, reported as micrograms of nitrogen per kilogram of sediment. DBF https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-nitrification-20200820.csv dataset Samples were collected in the lower reaches of Von Guerard stream from below the playa to about 200 m upstream of the F6 gage. Samples were taken on lateral transects extending from the channel center to the wetted margin. Full transect locations are included as a csv file. Porewater samplers were flexible polyethylene tubing (3/16” inner diameter) encased in a rigid plastic tube and screened at the bottom with fine metal mesh. We installed samplers to depths of both 15 and 30 cm at locations A-D on each transect. Nutrient and DOC samples were filtered through pre-combusted (4 hr at 450ºC) Whatman GF/C glass fiber filters. Nutrient samples were stored frozen in 60 mL HDPE bottles, while DOC and isotope samples were kept chilled (+4ºC) in the dark prior to analysis. Silica and DIN were measured colorimetrically immediately after thawing at room temperature by the Arikaree Environmental Laboratory, University of Colorado Boulder, using a Lachat (USA) QuikChem 8500 Flow Injection Autoanalyzer. Nitrate (as NO3– + NO2–) was analyzed by standard method 4500-NO3 I (cadmium reduction flow injection) with a detection limit of 0.004 mg NO3––N L–1. Samples were analyzed for NH4+ by standard method 4500-NH3 H (phenolate flow injection, detection limit of 0.005 mg NH4+–N L–1). For Si, the detection limit was 0.004 mg Si L–1 by standard method 4500-SiO2 F. We measured water isotopes (δ18O and δD) using a cavity ring-down spectrometer (Picarro, USA) and calculated deuterium excess as δD – 8*δ18O. For the nitrification potential assay we used sediment from two pilot transects during January 2018. We first removed the top 5 cm of the streambed to avoid contamination from benthic algal mats, then scooped sediment from approximately 5–10 cm depth into sterile Whirlpaks. These sediment samples were stored frozen and shipped to the University of Colorado Boulder for analysis. After thawing the samples at room temperature, we subsampled 20 g of wet sediment from each site in triplicate into sterile 250 mL HDPE bottles and an additional 20 g in triplicate into pre-weighed aluminum weigh boats. We dried the subsamples in the aluminum weigh boats at 105ºC for 24 hours and reweighed to calculate mean volumetric water content for each sampling location. For the samples in 250 mL HDPE bottles, we performed a nitrification potential assay using perchlorate and NH4+ in a phosphate (KH2PO4 and K2HPO4) buffered solution, which was mixed constantly with the sediment on a shaker table at room temperature. A detailed description of the assay protocol and solution concentrations is provided by Schmidt & Belser [1994]. We took subsamples from each replicate flask at 0, 1 and 8 hours then 1, 2, 3, and 5 days from the start of the assay. All subsamples were immediately filtered through Whatman GF/C glass fiber filters and stored frozen (-20ºC) until thawed for analysis. As perchlorate in the incubation solution inhibits the final oxidation of nitrite (NO2–) to NO3–, we analyzed the filtered aliquots for NO2– colorimetrically using a Lachat QuikChem 8500 Flow Injection Autoanalyzer. Accumulated NO2– concentrations were converted to mass NO2––N normalized by the calculated dry weight of sediment in each replicate flask. Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact