Kurt D. Carpenter 20240531 Data set https://doi.org/10.5066/P13RHWZC This data release contains plankton sampling results collected in the Willamette River in Portland, Oregon. The data release will be updated with new results as they are collected. The samples in this data release were collected at USGS stations 453027122400000 (Willamette River below the Holgate Channel), 452913122394300 (Ross Island Lagoon – Willamette River), and 453833122462700 (Willamette River at RM 1.5) between May 14 and August 14, 2024. Time-series water temperature, specific conductance, dissolved oxygen, pH, and chlorophyll and phycocyanin fluorescence data that were collected at 453027122400000 are available from the USGS National Water Information System (https://waterdata.usgs.gov/nwis). This data release is intended to be a repository for plankton sampling results collected in the Willamette River. Photomicrographs of representative organisms from the sampling events on 5/14/2024, 7/8/2004, and 8/14/2004 are stored in the compressed folders plankton_photos_05_14_24.zip, plankton_photos_07_08_24.zip, and plankton_photos_08_14_24.zip, respectively; photographer: Kurt Carpenter, Hydrologist, USGS Oregon Water Science Center. Use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U. S. Government. 20240514 20240814 ground condition Planned As needed Geographic extent of study -122.7530 -122.6115 45.5742 45.4100 ISO 19115 Topic Category inlandWaters environment biota USGS Thesaurus aquatic biology surface water quality USGS Metadata Identifier USGS:66468c3cd34e1955f5a4371c Geographic Names Information System Oregon Common Geographic Names Willamette River None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Kurt D. Carpenter USGS Oregon Water Science Center Research Hydrologist mailing and physical

601 SW 2nd Ave. Suite 1950

Portland OR 97204 US 503-251-3200 gs-w-or_sciencebase@usgs.gov The author would like to acknowledge the assistance provided by personnel from the East Multnomah Soil & Water Conservation District. Replicate samples included slide replicates (multiple sub-samples) and true replicate samples from the field. No logical consistency tests were conducted. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal horizontal positional accuracy tests were conducted. No formal vertical positional accuracy tests were conducted. Gerald Webber Prescott 1954 publication Dubuque, Iowa Wm. C Brown Company Series Name: The Pictured-Key Nature Series Issue Identification: Fresh-water Algae http://ia800202.us.archive.org/9/items/howtoknowfreshwa00pres/howtoknowfreshwa00pres.pdf Digital and/or Hardcopy 2024 publication date Prescott_et_al _1954 Provided methods for identifying species and genera of freshwater algae. John D. Wehr Robert G. Sheath 2003 publication n/a Elsevier https://doi.org/10.1016/B978-0-12-741550-5.X5000-4 Digital and/or Hardcopy 2003 publication date Wehr_Sheath _2003 Provided methods for identifying species and genera of freshwater algae. 1. Plankton net tow samples were collected using a 1-foot diameter 80-micron net, which was hand tossed into the river and towed for a distance of 10 feet. 2024 2. Five milliliters of each biomass sample collected in step (1) were transferred into a 20-milliliter plastic vial with 5 milliliters of native stream water, which doubled total sample volumes to 10 milliliters. 2024 3. The samples were placed on ice and transported to the USGS Oregon Water Science Center Laboratory in Portland, OR for analysis. 2024 4. Subsamples of plankton were concentrated in an open filter flask under gentle pressure onto a 0.45 micron membrane filter. Subsamples from this concentrate were transferred to glass slides and wet mounts were prepared. Up to three wet mounts were prepared, to document and catalogue the planktonic organisms. Typically > 100 “natural units” (colony, filament, or individual cells) were examined under bright field and phase contrast objectives using a Leica DM1000 microscope under 40x, 400x, and 1000x magnifications. Organisms were identified to genus or sometimes species, and photographed with a Zeiss Axiocam 208 camera mounted to the microscope. Taxon occurrences were then assigned values of 0 (absent), 1 (present but minor), or 2 (dominant or co-dominant). Identifications were made according to taxonomic references below cited for this processing step. Prescott_et_al _1954 Wehr_Sheath _2003 2024 5. The various organisms were identified to genus or species and documented as being present, dominant, or co-dominant. 2024 6. Photomicrographs were taken of the representative organisms in each sample. 2024 0.000001 0.000001 Decimal degrees data_dictionary.csv Description of the attributes in each data table in the data release Producer Defined GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P13RHWZC None 20240903 Daniel R. Wise USGS Oregon Water Science Center Hydrologist mailing and physical

601 SW 2nd Ave. Suite 1950

Portland OR 97204 US 503-251-3200 gs-w-or_sciencebase@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999