HZSEDS_DIATOMS English utf8 dataset McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact 2020-09-24 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Hyporheic diatom community assemblages from Von Guerard Stream, Taylor Valley, McMurdo Dry Valleys, Antarctica in January 2019 2020-09-24 publication Joshua Darling University of Colorado Boulder http://www.colorado.edu/ joshua.darling@colorado.edu pointOfContact Ruth Heindel Kenyon College https://www.kenyon.edu/ heindel1@kenyon.edu https://www.ruthcheindel.com/ pointOfContact 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 Anna Bergstrom Boise State University https://www.boisestate.edu/ annabergstrom@boisestate.edu pointOfContact Diane McKnight University of Colorado Boulder http://www.colorado.edu/ diane.mcknight@colorado.edu pointOfContact documentDigital In this data package, we present diatom community assemblages from hyporheic sediments collected in January 2019 from six transects across Von Guerard Stream, Taylor Valley, Antarctica. These samples were collected to address questions about the retention and processing of particulate organic matter in the hyporheic zone of McMurdo Dry Valley streams. The six transects were located at pools, riffles, and meanders (three of each geomorphology type) along Von Guerard Stream and extended across the stream channel to the edges of the wetted zone, ranging from 6.6 to 13.6 m in length. At each sampling location, we collected subsurface sediment sample that was preserved in formalin directly after sample collection. We characterized diatom assemblages by counting a total of 300 diatom valves from each preserved diatom sample. This data package is associated with a complementary data package that contains hyporheic sediment chemistry for the same samples. Name: Braeden Lukkari Role: lab technician Name: Renée F. Brown Role: data manager completed McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact population dynamics theme LTER Core Areas English Transect type is "meander." Coordinates provided by Ruth Heindel on 24 September 2020. 163.255683000000 163.255683000000 -77.610933000000 -77.610933000000 Transect type is "meander." Coordinates provided by Ruth Heindel on 24 September 2020. 163.296560000000 163.296560000000 -77.620117000000 -77.620117000000 Transect type is "pool." Coordinates provided by Ruth Heindel on 24 September 2020. 163.282600000000 163.282600000000 -77.618700000000 -77.618700000000 Transect type is "pool." Coordinates provided by Ruth Heindel on 24 September 2020. 163.293367000000 163.293367000000 -77.619867000000 -77.619867000000 Transect type is "riffle." Coordinates provided by Ruth Heindel on 24 September 2020. 163.256000000000 163.256000000000 -77.611083000000 -77.611083000000 Transect type is "riffle." Coordinates provided by Ruth Heindel on 24 September 2020. 163.280733000000 163.280733000000 -77.618467000000 -77.618467000000 2019-01-10 https://mcm.lternet.edu/sites/default/files/data/HZSEDS_DIATOMS_0.csv Hyporheic zone sediment diatoms eng; US McMurdo Dry Valleys LTER Hyporheic zone sediment diatoms Number of Header Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Internal dataset code. STREAM Name of the stream where sample was collected. SAMPLE_DATE Date samples were collected. Date Time Format: MM/DD/YYYY SAMPLE_ID Unique sample identifier that contains the geomorphology type, the transect number, and the lateral position. Sample identifiers are based on location, e.g., P1-3 refers to a sample collected from pool transect number 1 (upper transect) and at position 3 of 5 across the transect. M meander P pool R riffle TRANSECT Transect identifier. Transects are numbered from north to south. M meander P pool R riffle GEOMORPH Geomorphic classification type of the sample/transect location. LATERAL_POSITION Lateral position of the sample across the transect. 1 margin of the wetted zone (inside bank for meanders) 2 intermediate 3 stream thalweg 4 intermediate 5 margin of the wetted zone (outside bank for meanders) TAXON_ID Taxon identifier relates observed species to current (as of August 2020) taxonomy updated to the Antarctic Freshwater Diatoms Database: http://huey.colorado.edu/diatoms/taxa/index.php SPECIES Genus and specific epithet of species using taxonomy current as of August 2020. ABUNDANCE Qualitative, percent relative abundance for each species in each sample. DBF https://mcm.lternet.edu/sites/default/files/data/HZSEDS_DIATOMS_0.csv dataset Field MethodsDuring January 2019, we collected hyporheic sediments nine transects across pools, meanders, and riffles along Von Guerard Stream in Taylor Valley, Antarctica. Each transect was composed of five sampling sites at different lateral positions across the stream channel: two sampling sites were located at the margins of the visible wetted zone, one sampling site was directly under the thalweg, and two sampling sites were located halfway between the wetted margin and the thalweg. Transects ranged from 6.6 m to 13.6 m in total length across the stream channel. At each sampling site, we removed the surface sediment and mat material in order to focus our sampling on the underlying hyporheic sediments. To characterize the diatom assemblages, we collected a sample in a plastic scintillation vial that was preserved in formalin directly after sample collection. Laboratory AnalysesDiatom assemblages were characterized at six of the nine transects (two transects for pool, meander, and riffle) by counting a total of 300 diatom valves from preserved samples. First, a subset of sediment was transferred to 50 mL centrifuge tubes. We cleaned samples of organic content by digesting with hydrogen peroxide (30 mL of 30% H2O2) for 48 hours at 100ºC. After digestions were complete, samples were repeatedly rinsed with distilled water until a neutral pH was reached. We isolated diatoms from sand grains and other mineral aggregates through repeated resuspension and centrifugation to carefully retain the diatoms in the supernatant. Aliquots of supernatant were dried on coverslips and mounted to glass microscope slides using a highly refractive adhesive (Zrax, W. P. Dailey, Philadelphia, USA). We counted diatoms at 1250x magnification on an Olympus BX50 DIC microscope and identified taxa using descriptions listed in the Antarctic Freshwater Diatoms Database. Fragmented diatom frustules were identified to the highest taxon-level possible (mostly genus level). All relative abundance composition data was standardized to the total number of diatom valves counted per sample.   Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact