uid=MCM,o=EDI,dc=edirepository,dc=org all public read VGPW Joel Singley

Institute of Arctic and Alpine Research Boulder CO 80303 US

joel.singley@colorado.edu https://orcid.org/0000-0002-7906-8491 Michael Gooseff michael.gooseff@colorado.edu http://goosefflab.weebly.com https://orcid.org/0000-0003-4322-8315 Diane McKnight diane.mcknight@colorado.edu https://orcid.org/0000-0002-4171-1533 Eve-Lyn Hinckley eve.hinckley@colorado.edu https://orcid.org/0000-0002-7081-0530 McMurdo Dry Valleys LTER http://mcmlter.org/ Kathleen Welch kathleen.welch@colorado.edu https://orcid.org/0000-0003-1028-3086 lab technician Anna Bergstrom annabergstrom@boisestate.edu https://orcid.org/0000-0002-9684-4018 lab technician Renée Brown rfbrown@unm.edu https://orcid.org/0000-0002-4986-7663 data manager 2021-03-25 English

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. 

dissolved inorganic nitrogen dissolved nutrients dissolved organic carbon hyporheic zone inorganic nitrogen isotopes nitrate nitrification nitrite nitrogen nitrogen cycling nutrient cycles nutrient cycling sediments silica specific conductivity streamflow streams LTER Controlled Vocabulary Antarctic desert streams deuterium isotope ratio dissolved inorganic nitrogen dissolved organic carbon DOC hyporheic zone inorganic nitrogen isotope isotope ratio LTER McMurdo Dry Valleys nitrogen oxygen isotope ratio sediment specific conductivity streamflow Taylor Valley Station Keywords inorganic nutrients LTER Core Areas

This data package is released under the Creative Commons Attribution 4.0 International License (CC BY 4.0; http://creativecommons.org/licenses/by/4.0/), which allows consumers (hereinafter referred to as “Data Users”) to freely reuse, redistribute, transform, or build on this work (even commercially) so long as appropriate credit is provided. Accordingly, Data Users are required to properly cite this data package in any publications or in the metadata of any derived products that result from its use (in whole or in part). A recommended citation is provided on the summary metadata page associated with this data package in the McMurdo Dry Valleys LTER Data Catalog (https://mcmlter.org/data), and a generic citation may be found on the summary metadata page in the repository where this data package was obtained. When these data contribute significantly to the contents of a publication, Data Users must also acknowledge that data were provided by the NSF-supported McMurdo Dry Valleys Long Term Ecological Research program (OPP-2224760). This data package has been released in the spirit of open scientific collaboration. Hence, Data Users are strongly encouraged to consider consultation, collaboration, and/or co-authorship (as appropriate) with the data package creator(s). Data Users should be aware these data may be actively used by others for ongoing research; thus, coordination may be necessary to prevent duplicate publication. Data Users should also recognize that misinterpretation of data may occur if they are used outside the context of the original study. Hence, Data Users are urged to contact the data package creator(s) if they have any questions regarding methodology or results. While substantial efforts are made to ensure the accuracy of this data package (with all its components), complete accuracy cannot be guaranteed. Periodic updates to this data package may occur, and it is the responsibility of Data Users to check for new versions. This data package is made available “as is” and comes with no warranty of accuracy or fitness for use. The creator(s) of this data package and the repository where these data were obtained shall not be liable for any damages resulting from misinterpretation, use, or misuse of these data. Finally, as a professional courtesy, we kindly request Data Users notify the primary contact referenced in the metadata when these data are used in the production of any derivative work or publication. Notification should include an explanation of how the data were used, along with a digital copy of the derived product(s). Thank you.

https://mcm.lternet.edu/content/surface-and-hyporheic-porewater-chemistry-and-sediment-nitrification-potentials-von-guerard 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 19 19 meter 2018-01-20 2020-01-25 McMurdo Dry Valleys LTER Information Manager im@mcmlter.org McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER

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.

VGPW_CHEM Water chemistry data for concurrent surface and porewater samples, organized by sampling location, sampling time, and solute (DIN species, DOC, and water isotopes). mcmlter-strm-singley-vgpw-chemistry-20210325.csv 47531 1 1 column , " https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-chemistry-20210325.csv 2018-01-20 2020-01-25 DATASET_CODE Dataset Code Internal dataset code. string Internal dataset code. STRMGAGEID Stream Gage ID Stream Gage ID. string Stream Gage ID. STREAM_NAME Stream Name Name of the stream. string Name of the stream. SAMPLE_ID Sample ID Alphanumeric code indicating sample year and sequential number. string Alphanumeric code indicating sample year and sequential number. DATE_TIME Date and Time Date and time of sample collection (MM/DD/YYYY HH:MM UTC+13). date MM/DD/YYYY HH:MM UTC+13 SAMPLE_TYPE Sample Type Type of sample. string surface surface water pore hyporheic porewater SAMPLE_YEAR Sample Year Year of sample collection. date YYYY TRANSECT 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. string 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 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. string 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 Sample depth For pore samples, indicates the depth of sampler intake below streambed surface, where 0 = surface water, 15 = 15 cm, and 30 = 30 cm. centimeter real N_NO3_MGL Nitrate concentration Concentration of nitrogen as nitrate + nitrite in milligrams of nitrogen per liter. milligramsPerLiter real N_NO3_COMMENTS Nitrate Concentration Comments Comments regarding nitrate concentrations, where ND = not detected and NM = not measured. string Comments regarding nitrate concentrations, where ND = not detected and NM = not measured. N_NH4_MGL Ammonium concentration Concentration of nitrogen as ammonium in milligrams of nitrogen per liter. milligramsPerLiter real N_NH4_COMMENTS Ammonium Concentration Comments Comments regarding ammonium concentrations, where ND = not detected and NM = not measured. string Comments regarding ammonium concentrations, where ND = not detected and NM = not measured. SI_MGL Dissolved silica concentration Dissolved silica concentration in milligrams of silica per liter. milligramsPerLiter real SI_COMMENTS Dissolved Silica Concentration Comments Comments regarding dissolved silica concentrations, where ND = not detected and NM = not measured. string Comments regarding dissolved silica concentrations, where ND = not detected and NM = not measured. DOC_MGL Dissolved organic carbon Dissolved organic carbon concentration in milligrams of carbon per liter. milligramsPerLiter real DOC_COMMENTS Comments regarding DOC Comments regarding dissolved organic carbon concentrations, where ND = not detected and NM = not measured. string Comments regarding dissolved organic carbon concentrations, where ND = not detected and NM = not measured. D18O_PERMIL Oxygen-18 Isotope Ratio δ18O isotope ratio reported in reported in parts per thousand (per mil, ‰). perMil real DD_PERMIL Deuterium Isotope Ratio δD isotope ratio reported in reported in parts per thousand (per mil, ‰). perMil real DEXCESS Deuterium excess Deuterium excess as calculated by δD-8*δ18O. perMil real ISOTOPE_COMMENTS Comments regarding isotopes Comments regarding all isotope values, where ND = not detected and NM = not measured. string Comments regarding all isotope values, where ND = not detected and NM = not measured. SC_USCM Specific conductivity Specific conductivity in microSiemens per centimeter. microSiemensPerCentimeter real SC_COMMENTS Comments regarding specific conductivity Comments regarding specific conductivity, where ND = not detected and NM = not measured. string Comments regarding specific conductivity, where ND = not detected and NM = not measured. INUNDATED Inundation Code Identifies whether sampling location was inundated by surface water at time of sample collection. Surface water samples are noted with “Yes”. string Yes Inundated No Not inundated VGPW_LOCATIONS Location information for sampling transects along Von Guerard Stream. mcmlter-strm-singley-vgpw-locations-20210325.csv 865 1 1 column , " https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-locations-20210325.csv DATASET_CODE Dataset Code Internal dataset code. string Internal dataset code. STRMGAGEID Stream Gage ID Stream gage ID. string Stream gage ID. STREAM_NAME Stream Name Name of the stream. string Name of the stream. TRANSECT Transect Alphanumeric transect identifier, number increases from upstream to downstream. string Alphanumeric transect identifier, number increases from upstream to downstream. SAMPLE_YEAR Sample Year Year in which sample was collected. date YYYY LATITUDE Latitude Sampling transect latitude. decimalDegrees real LONGITUDE Longitude Sampling transect longitude. decimalDegrees real VGPW_NITRIFICATION Laboratory nitrification potential assay data for sediments collected from Von Guerard Stream.  mcmlter-strm-singley-vgpw-nitrification-20200820.csv 8966 1 1 column , " https://mcm.lternet.edu/sites/default/files/data/mcmlter-strm-singley-vgpw-nitrification-20200820.csv DATASET_CODE Dataset code Internal dataset code. string Internal dataset code. STRMGAGEID Stream Gage ID Stream Gage ID. string Stream Gage ID. STREAM_NAME Stream Name Name of the stream. string Name of the stream. SAMPLE_ID Sample ID Code indicating sediment sample location, prior to replication. string Code indicating sediment sample location, prior to replication. SAMPLE_YEAR Sample Year Year sample was collected. date YYYY TRANSECT Transect. Alphanumeric transect identifier, number increases from upstream to downstream. string Alphanumeric transect identifier, number increases from upstream to downstream. SITE Site Lateral site on the transect. string A Center of channel C Wetted margin REPLICATE Replicate Replicate identifier within the same sampling site. string Replicate identifier within the same sampling site. ELAPSED_TIME_DAY Elapsed Time Time (in days) since the beginning of the nitrification potential assay. day real N_NO2_UGL Nitrite concentration Concentration of nitrogen as nitrite in aliquot, reported in micrograms of nitrogen per liter. microgramsPerLiter real N_NO2_COMMENTS Comments regarding nitrate concentration Comments regarding nitrate concentration, where NM = not measured. string Comments regarding nitrate concentration, where NM = not measured. DRY_SED_G Dry mass of sediment Dry mass of sediment in flask, reported as grams of sediment. grams real VOLUME_L Volume Volume of incubation solution in liters. liter real N_NO2_UGKG Nitrate concentration normalized to dry mass sediment Nitrogen as nitrate concentration normalized to dry mass sediment, reported as micrograms of nitrogen per kilogram of sediment. microgramsPerKilogram real perMil (ppt) Derivative of the standard SI unit of electrical conductance (specific conductance). day (86400 seconds)