Wetland Paleoecological Study of Coastal Louisiana: Sediment Cores and Diatom Samples Dataset

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Frequently anticipated questions:

What does this data set describe?

Title:
Wetland Paleoecological Study of Coastal Louisiana: Sediment Cores and Diatom Samples Dataset
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 depth-interval samples of sediment cores.
Supplemental_Information:
This metadata describes data on field sites and sediment core collection (sediment_core_sites.txt), laboratory analyses of sediment sampled from cores at 2-cm depth intervals (sediment_core_properties.txt) and diatom species counts from sediment sampled at select 2-cm depth intervals (sediment_core_diatom.txt). For diatom species counts, attributes are assigned a species code that is defined by the taxa's genus and species name. A description of the code set is found in the included taxa_list.txt file.
  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: Sediment Cores and Diatom Samples Dataset.

    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?
    Beginning_Date: 29-Apr-2009
    Ending_Date: 30-Apr-2009
    Currentness_Reference:
    field collection date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Entity point (46)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 8.98315284119521e-009. Longitudes are given to the nearest 8.98315284119521e-009. Latitude and longitude values are specified in Decimal Degrees. The horizontal datum used is D WGS 1984.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    sediment_core_sites.txt
    Location and environmental data for sediment core sites (Source: USGS)
    Site
    Site identification number (Source: USGS) The site code begins with the Field Activity Number (FAN) 09WCC01. Last two digits are the site identification numbers: 01 through 09.
    Latitude
    Latitude coordinates in decimal degrees (WGS 1984) (Source: USGS)
    Range of values
    Minimum:29.5632
    Maximum:29.9624
    Units:decimal degrees
    Longitude
    Longitude coordinates in decimal degrees (WGS 1984) (Source: USGS)
    Range of values
    Minimum:-93.6981
    Maximum:-92.0418
    Units:decimal degrees
    Date
    Date sample was collected (Source: USGS) Date is in MM/DD/YYYY format
    Time
    The time when sample was collected (Source: USGS) Time is in hh:00 AM/PM format; central daylight savings time (CDT)
    SW_depth
    Surface water depth (cm) (Source: USGS)
    Range of values
    Minimum:2.0
    Maximum:16.0
    Units:centimeters
    Field_length
    Total length of the core measured in the field prior to transport to the lab (cm) (Source: USGS)
    Range of values
    Minimum:50
    Maximum:62
    Units:centimeters
    Lab_length
    Total length of the core measured in the lab after transport from the field (cm) (Source: USGS)
    Range of values
    Minimum:46
    Maximum:60
    Units:centimeters
    SW_salinity
    Surface water salinity (ppt) (Source: USGS)
    Range of values
    Minimum:6.0
    Maximum:20.1
    Units:parts per thousand
    PW10_salinity
    Pore water salinity at 10cm depth (ppt) (Source: USGS)
    Range of values
    Minimum:10.0
    Maximum:22.3
    Units:parts per thousand
    PW30_salinity
    Pore water salinity at 30cm depth (ppt) (Source: USGS)
    Range of values
    Minimum:13.7
    Maximum:22.3
    Units:parts per thousand
    sediment_core_properties.txt
    Sediment properties for sediment core samples (Source: USGS)
    Sample
    Sample identification number (Source: USGS) The sample identification number is a combination of the site ID, such as 09WCC01_SS_DD, where 09WCC01 is the Field Activity Number, SS is the core site (01 through 09), and DD is the mid-depth of the sample interval in 2-cm increments.
    BD
    Average bulk density (g/mL) (Source: USGS)
    Range of values
    Minimum:0.1122
    Maximum:0.6031
    Units:grams per milliliter
    BD_N
    Total number of samples analyzed for bulk density (Source: USGS)
    Range of values
    Minimum:1
    Maximum:3
    BD_SD
    Standard deviation of bulk density (g/mL) when sampled more than once (Source: USGS)
    Range of values
    Minimum:0
    Maximum:0.1224
    Units:grams per milliliter
    LOI
    Loss-on-ignition (%) (Source: USGS)
    Range of values
    Minimum:8.45
    Maximum:58.32
    Units:percent
    LOI_N
    Total number of samples analyzed for loss-on-ignition (Source: USGS)
    Range of values
    Minimum:1
    Maximum:5
    LOI_SD
    Standard deviation of Loss-on-ignition (%) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:5.26
    Units:percent
    Sand
    Grain size: percent sand (%) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    Sand_SD
    Grain size: standard deviation of percent sand (Source: USGS)
    Range of values
    Minimum:0
    Maximum:4.30
    Units:percent
    Mud
    Grain size: percent mud (silt + clay sized particles) (%) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    Mud_SD
    Grain size: standard deviation of percent mud (silt + clay sized particles) (%) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:4.2
    Units:percent
    Clay
    Grain size: percent clay (Source: USGS)
    Range of values
    Minimum:8.76
    Maximum:34.5
    Units:percent
    SD_Clay
    Grain size: standard deviation of percent clay (%) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:2.3
    Units:percent
    Pb210
    Total activity of lead radioisotope (Pb-210) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:13.1
    Units:degradations per minute per gram
    Pb_error
    Error for total activity of lead radioisotope (Pb-210) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:0.3
    Units:degradations per minute per gram
    Cs137
    Total activity of cesium radioisotope (Cs-137) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:9
    Units:degradations per minute per gram
    Cs_error
    Total activity of cesium radioisotope (Cs-137) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:0.4
    Units:degradations per minute per gram
    Ra226
    Total activity of radium isotope (Ca-226) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:1.7
    Units:degradations per minute per gram
    Ra_error
    Error of total activity of radium isotope (Ra-226) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:0.2
    Units:degradations per minute per gram
    K40
    Total activity of potassium radioisotope (K-40) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:50.0
    Units:degradations per minute per gram
    K_error
    Error of total activity of potassium radioisotope (K-40) in dpm/g (Source: USGS)
    Range of values
    Minimum:0
    Maximum:4.0
    Units:degradations per minute per gram
    sediment_core_diatoms.txt
    Diatom counts for sediment core samples (Source: USGS)
    Sample
    Sample identification number (Source: USGS) The sample identification number is a combination of the site ID, such as 09WCC01_SS_DD, where 09WCC01 is the Field Activity Number, SS is the core site (01 through 09), and DD is the mid-depth of the sample interval in 2-cm increments.
    Gen_spec
    Percent of total diatoms counted that were identified by species. The attribute label is coded by species name. Please see the Entity and Attribute Overview for additional information. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    taxa_list.txt
    Diatom species codes and species definitions, with authority, references, and count information. (Source: USGS)
    Code
    Species code (Source: USGS) The species code is typically in the form Gen_spec where Gen is a three letter code for the Genus and spec is the four letter code for the species. The inclusion of cf suggests the species appears similar to the reference identification, but may be slightly different in some of the descriptive characteristics. The code spp suggests a species complex, where specimens were identified only to the genus level. The code spp1 indicates a species not identified in available flora, but consistent specimens were grouped accordingly.
    Taxon
    Full species name (Source: USGS) Full species name with both Genus and species. The most recent nomenclature was used whenever possible. The inclusion of cf suggests the species appears similar to the reference identification, but may be slightly different in some of the descriptive characteristics. The code spp suggests a species complex, where specimens were identified only to the genus level. The code spp1 indicates a species not identified in available flora, but consistent specimens were grouped accordingly.
    Authority
    Species Authority (Source: USGS) The full authority for the binomial name is given as described in the Catalogue of Diatom Names (http://researcharchive.calacademy.org/research/diatoms/names/)
    Reference
    Reference used to identify the specimen (Source: USGS) Citation (author and year only) used to identify the specimen. Full reference is available within the References Cited section of the data series (https://pubs.usgs.gov/ds/0877)
    Total_Surf
    Total number of surface sediment sites in which the species was identified (N=46) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:46
    Total_Core
    Total number of core sediment samples in which the species was identified (N=47) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:47
    Entity_and_Attribute_Overview:
    For diatom species counts, the attribute labels are defined by a species code set that was created from the scientific species name. Species codes can be found in the Taxa list at https://pubs.usgs.gov/ds/0877 or in the included taxa_list.txt file.
    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 5)
    Cores were collected at Rockefeller Wildlife Refuge (RWR) aboard an airboat. RWR is state-owned refuge that is managed primarily for waterfowl and fishery habitat with a primary mission of promoting 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 distant 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 clear acrylic tube, 10-cm in diameter into the marsh. The barrel edge was sharpened and vegetation around the extraction point's perimeter was sliced to reduce compaction during tube insertion. Compaction was estimated by measuring the difference in the marsh elevation between the inside and outside of the barrel top prior to extraction. The tube was capped and extracted from the sediment with a handle constructed of 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, to withdraw a water sample. The water sample was placed in a cup and salinity was measured with a handheld YSI conductivity probe.
    The cores were sealed and transported to the lab. The cores remained cold and vertical during transport in an insulated and lined 50-gallon barrel containing ice. Upon arrival at the lab, the cores were x-radiographed (58-64 kV, 2.0 mAs) with 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.
    Field data was hand-entered into Microsoft Excel 2010, double-checked for accuracy, and exported into a comma-delimited text file. 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
    • sediment_core_sites.txt
    Date: 2011 (process 2 of 5)
    Laboratory procedure: All sediment core samples were analyzed for bulk density, organic carbon, and lead-dating. A 30-mL sediment sample was weighed wet, dried in an oven at 60 °C, and weighed again to calculate bulk density (dry mass divided by volume). Loss-on-ignition (LOI) was determined by grinding the dried sample into a fine powder and combusting a subsample at 650 °C for four hours. Lead-210 was determined by measuring the activity of Po-210 using alpha-spectrometry. Polonium-210 is assumed to be in secular equilibrium with its parent Pb-210. The fired sample from LOI analysis was transferred to a glass beaker and Po-210 was acid leached from the sediment. A known quantity of the tracer Po-209 was added to the solution prior to auto-plating and counted on low-level alpha spectrometer coupled to a pulse-height analyzer. Reported errors are the statistical counting errors at the 95 percent confidence interval. At least five samples per core were processed in duplicate in order to calculate relative standard deviation for an estimate of between sample errors. Select core samples were identified for gamma-ray spectrometry (Cs-137) by examining Pb-210 profile data, isolating the depth where the detectable limit where excess Pb-210 reaches zero (provides a rough estimate 100 years before present), and estimating where Cs-137 activity would likely be detected (1950 to 1984). Approximately 15 g of dried, ground sample was sealed in a plastic jar and stored for at least 3 weeks to allow activity to reach equilibrium. Samples were counted using a germanium detector for low-energy gamma rays and a multi-channel analyzer was used for data collection. Samples were counted for at least 24 hours or until counting errors were less than 5 percent. In addition, select core samples were processed for grain size by examining x-ray images and bulk density data to identify possible changes in sedimentary layers. Data was hand entered into Microsoft Excel, double-checked for accuracy, and exported into a comma-delimited text file. 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 used in this process:
    • sediment core samples
    • x-radiographs
    • 09WCC01_core_descriptions.pdf
    Data sources produced in this process:
    • sediment_core_properties.txt
    Date: 2012 (process 3 of 5)
    Microfossil analyses: Approximately 0.5 mL of sediment was digested in a 100-mL beaker using hydrogen peroxide and potassium dichromate. Samples were rinsed twice with deionized (DI) water (the beaker was filled with DI water; sample was allowed to settle overnight, decanted to 500-mL mark, and refilled, etc.). Since samples contained a significant fraction of fine-grained sediment (silt and clay), a 7 percent sodium hexametaphosphate solution was added to deflocculate fine-grained sediments. Each sample was continually rinsed until decant was clear. A known volume (5 or 10 mL depending on the density of diatoms and sand grains) of diatom solution was added to settling trays containing four cover slips and allowed to dry (Battarbee, 1973). Cover slips were sealed to microscope slides using Zrax diatom mountant (refractive index ~ 1.7+). A minimum of 300 diatoms were identified to species and counted using a Nikon Optiphot light microscope at 1000x magnification (Plan 100x / 1.25 oil DIC objective). The identification of species and autecology, including general salinity preferences, was determined from taxonomic literature. Each species identified was given a code, composed of the genus and species name, and checked with surface sediment samples of the same area for differences. Any species missing from the regional assessment were added. Data was hand-entered into Excel, double-checked for accuracy, and exported as a comma-delimited text file. 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 used in this process:
    • physical sediment samples
    Data sources produced in this process:
    • sediment_core_diatoms.txt
    • taxa_list.txt
    Date: 28-Mar-2018 (process 4 of 5)
    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
    Date: 13-Oct-2020 (process 5 of 5)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@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 sample collection, preparation, and analyses. When replicate samples were collected, the standard deviation is provided. Several replicate diatom species counts were conducted to determine consistency and were found to be similar suggesting procedures had a high-degree of accuracy; however, no statistical procedures detailing accuracy were conducted. Species identities are dependent on available flora and uncertainty in species identifications are noted via "cf." in the species name.
  2. How accurate are the geographic locations?
    Horizontal positions were determined with a handheld GPS. Expected horizontal accuracy for site surveys is 0.005 to 0.020 meters.
  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: text file (TXT)
      Network links: https://pubs.usgs.gov/ds/0877
    • Cost to order the data: None, if obtained online

Who wrote the metadata?

Dates:
Last modified: 09-Nov-2021
Metadata author:
U.S. Geological Survey
Attn: Kathryn Smith
Ecologist
600 4th Street South
St. Petersburg, FL
USA

727-502-8000 (voice)
kelsmith@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/09WCC01_sediment_core_metadata.faq.html>
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