Wetland Paleoecological Study of Coastal Louisiana: X-radiographs

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Frequently anticipated questions:


What does this data set describe?

Title:
Wetland Paleoecological Study of Coastal Louisiana: X-radiographs
Abstract:
Wetland sediment data was collected from coastal Louisiana as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the identification of sediment deposits for tropical storms. The complete dataset includes forty-six surface sediment samples and nine sediment cores. The surface sediment samples were collected in fresh to brackish marsh throughout the southwest Louisiana Chenier plain and are located coincident with Coastwide Reference Monitoring System (CRMS). Sediment cores were collected at Rockefeller Wildlife Refuge. The data described here include sedimentary properties, radioisotopes, x-radiographs, and diatom species counts for sediment cores.
Supplemental_Information:
X-radiographs are in 8-bit bitmap (BMP) format. Multiple BMP files were required for each core, due to core length. Files are named according to field activity (09WCC01), site number (01 to 09), and the vertical position of the image. Vertical position of image, from top to bottom of the core include: top = top of core, top_mid= top middle, middle = middle, bot_mid = bottom middle, and bot = bottom. Images contain vertical overlap so that the center of the image can be used in order to reduce vertical image distortion. Cores have three to four images each, depending on length necessary to film each core with overlap, so a top_mid plus a bot_mid image or just one middle image.
  1. How might this data set be cited?
    Smith, Kathryn E.L., Flocks, James G., Steyer, Gregory D., and Piazza, Sarai C., 20140929, Wetland Paleoecological Study of Coastal Louisiana: X-radiographs.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -92.615035
    East_Bounding_Coordinate: -92.578566
    North_Bounding_Coordinate: 29.636539
    South_Bounding_Coordinate: 29.588228
  3. What does it look like?
    pages/figures/Fig1_map.jpg (JPG)
    Map of the location of sample sites in the Chenier Plain of southwest Louisiana (inset A). Surface sediment sample stations (circles) were collected throughout the Chenier Plain at monitoring stations. Sediment cores (stars) were collected at Rockefeller Wildlife Refuge (inset B).
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 13-May-2009
    Currentness_Reference:
    image date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster image
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The X-radiograph image is in BMP (8-bit) format; number of pixels varies. Images are black and white, where pixel values reflect x-ray intensity on the photographic film and are indications of soil density. The lighter the pixel value, the greater the soil density (due to reduced radiation penetration through the core to reach the photographic paper). Numbers on the left side of the core image depict length; however, numbers are negative and begin at the bottom of the core and increase to the top of the core, therefore they should only be used as a guide for aligning image overlap.
    Entity_and_Attribute_Detail_Citation:
    Smith, K.E.L., Flocks, J.G., Steyer, G.D., and Piazza, S.C., 2014, Wetland Paleoecological Study of Coastal Louisiana: Sediment Cores and Diatom Calibration Dataset: U.S. Geological Survey Data Series 877. [Available at https://doi.org/10.3133/ds877]

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Kathryn E.L. Smith
    • James G. Flocks
    • Gregory D. Steyer
    • Sarai C. Piazza
  2. Who also contributed to the data set?
    Data are provided by the USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) through funding from the Coastal and Marine Geology Program. The USGS National Wetlands Research Center (NWRC) and Louisiana Department of Natural Resources are recognized as essential collaborators in sample collection.
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Kathryn Smith
    Ecologist
    600 4th Street South
    St. Petersburg, Florida
    USA

    727-502-8000 (voice)

Why was the data set created?

To investigate the use of diatoms as a proxy for past water chemistry and identification of historic storms.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: Apr-2009 (process 1 of 2)
    Cores were collected at Rockefeller Wildlife Refuge (RWR) using an airboat. RWR is state-owned refuge that is managed primarily for waterfowl and fishery habitat with a primary mission to promote scientific research. Five core sites were located along a transect perpendicular to the Gulf of Mexico coastline, ranging from 0.5 to 5.75 km from the shoreline. To examine small-scale variation, two additional sites were located 100 meters to the east and west of site 09WCC01_04 and parallel to the shore. Two additional sites were located to the west and east of the transect.
    Sediment was extracted by pushing a 10-cm diameter, clear acrylic tubes into the marsh. The barrel edge was sharpened and vegetation was sliced around the perimeter of the tube to reduce compaction during tube insertion. Compaction was estimated by measuring the difference in the marsh elevation between the inside and outside of the top of the barrel prior to extraction. The tube was capped and extracted from the sediment using a handle constructed from PVC. Geographic position, time of day, water depth, and surface water salinity were measured at each site. Porewater salinity was measured by driving a narrow plastic tube to a depth of 10 cm and using suction, supplied by an attached syringe, a sample of water was withdrawn. The water sample was placed in a cup and salinity measured using a handheld probe.
    The cores were sealed and transported to the lab. The cores remained cold and vertical during transport by placing them in an insulated and lined 50-gallon plastic barrel with ice. Upon arrival at the lab, the cores were x-radiographed (58-64 kV, 2.0 mAs) using a Torrex 120 portable X-ray unit and a ScanX CR2500 imaging system (exposure setting 58/2.0), producing bitmap files at 4457 x 5500-6000 pixels, 8-bit depth and approximate 23-25MB each. After imaging, cores were extruded and sliced at 2-cm intervals. Compaction from core transport and sampling (extrusion) were estimated by the difference between the measured lengths of the core before and after each procedure. Sedimentary characteristics (sediment texture, physical characteristics, presence of roots/shells/burrow, and stratification type) were described in detail during the sampling process and recorded on core description sheets. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Kathryn Smith
    Ecologist
    600 4th Street South
    St. Petersburg, Florida
    USA

    727-502-8000 (voice)
    Data sources produced in this process:
    • sediment core samples
    • x-radiographs
    • 09WCC01_core_descriptions.pdf
    Date: 28-Mar-2018 (process 2 of 2)
    Keywords section of metadata optimized by correcting variations of theme keyword thesauri and updating/adding keywords. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Arnell S. Forde
    Geologist
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    aforde@usgs.gov
  3. What similar or related data should the user be aware of?
    Smith, Kathryn E.L., 2012, Paleoecological Study of Coastal Marsh in the Chenier Plain, Louisiana: Investigating the Diatom Composition of Hurricane-Deposited Sediments and a Diatom-Based Quantitative Reconstruction of Sea-Level Characteristics: University of Florida Thesis (Ph.D.), Gainesville, FL.


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The validity or accuracy of information is dependent on image collection and exposure settings. Effort was made to make consistent images.
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Data are complete.
  5. How consistent are the relationships among the observations, including topology?
    No tests for fidelity were performed.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints:
Prior to use of these records in any analysis or report, the USGS must be notified and if used the provenance of the original data must be acknowledged. Acknowledge the use of specific records from contributing USGS databases and recognize the limitations of data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: Kathryn Smith
    Ecologist
    600 4th Street South
    St. Petersburg, Florida
    USA

    727-502-8000 (voice)
    kelsmith@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    This publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Bitmap (BMP)
      Network links: https://pubs.usgs.gov/ds/0877
    • Cost to order the data: None, if obtained online


Who wrote the metadata?

Dates:
Last modified: 28-Mar-2018
Metadata author:
U.S. Geological Survey
Attn: Kathryn Smith
Ecologist
600 4th Street South
St. Petersburg, FL
USA

727-802-8000 (voice)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/09WCC01_xray_metadata.faq.html>
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