Wetland Paleoecological Study of Coastal Louisiana: Surface Sediment and Diatom Calibration Dataset

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Frequently anticipated questions:


What does this data set describe?

Title:
Wetland Paleoecological Study of Coastal Louisiana: Surface Sediment and Diatom Calibration 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 both sedimentary properties and diatom species counts for the surface sediment samples.
Supplemental_Information:
This metadata describes data on laboratory analyses of surface sediment samples collected at CRMS sites (surface_sediment_properties.txt) and diatom species counts from these same samples (surface_sediment_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: Surface Sediment and Diatom Calibration Dataset.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -93.698100
    East_Bounding_Coordinate: -89.604200
    North_Bounding_Coordinate: 29.962400
    South_Bounding_Coordinate: 29.243800
  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: 02-Feb-2010
    Ending_Date: 01-Apr-2010
    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?
    surface_sediment_properties.txt
    Sediment properties for surface sediment samples (Source: USGS)
    Site
    Site identification number (Source: USGS) A three- to four-digit number depicting the site identification number as defined by CRMS.
    Latitude
    Latitude coordinate 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
    BD
    Bulk density (g/mL) (Source: USGS)
    Range of values
    Minimum:0.0657
    Maximum:0.6347
    Units:grams per milliliter
    LOI
    Loss-on-ignition (organic carbon) (Source: USGS)
    Range of values
    Minimum:10.34
    Maximum:88.53
    Units:percent
    GS_sand
    Grain size: percent silt (Source: USGS)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    GS_silt
    Grain size: percent silt (Source: USGS)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    GS_clay
    Grain size: percent silt (Source: USGS)
    Range of values
    Minimum:0
    Maximum:100
    Units:percent
    GS_mean
    Grain size: mean grain size (phi) (Source: USGS)
    Range of values
    Minimum:4.5
    Maximum:30.8
    Units:phi intervals
    GS_sd
    Grain size: mean grain size standard deviation (phi) (Source: USGS)
    Range of values
    Minimum:0.08
    Maximum:3.5
    Units:phi intervals
    GS_sort
    Grain size: sorting (describes the distribution of grain size) (Source: USGS)
    Range of values
    Minimum:2.1
    Maximum:7.5
    Units:phi intervals
    GS_skew
    Grain size: skewness (describes grain size distribution) (Source: USGS)
    Range of values
    Minimum:-0.5
    Maximum:0.25
    Units:phi intervals
    GS_kurt
    Grain size: kurtosis (describes grain size distribution) (Source: USGS)
    Range of values
    Minimum:0.6
    Maximum:1.2
    Units:phi intervals
    surface_sediment_diatoms.txt
    Diatom counts for surface sediment samples (Source: USGS)
    Site
    Site identification number (Source: USGS) A three- to four-digit number depicting the site identification number as definied by the CRMS.
    Gen_spec* (multiple attributes represented by unique species codes, see Entity and Attribute Overview)
    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
    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 codeset that was created from the scientific species name. Species codes can be found in the Taxa list in the data series 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

    727-803-8747 (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: 2010 (process 1 of 4)
    Sediment sample field collection: Surficial sediment samples were collected from a network of permanent wetland monitoring stations called the Coastwide Reference Monitoring System (CRMS). All sampled stations were located in the Chenier Plain in southwest Louisiana and were sampled to include representative salinity regimes for the region. Samples were collected by pushing a 10-cm diameter polyvinyl carbonate cylinder into the sediment and removing the surface 0-2 cm surface by extrusion. This procedure was selected because it replicated the sampling procedure interval of the sediment cores. Samples were labeled using CRMS site identification numbers and environmental data (salinity, water level, elevation, sediment accretion, and vegetation) for each site was obtained from CRMS monitoring data. All samples were stored in leak-proof containers, treated with isopropyl alcohol and placed on ice immediately to preserve the sample and reduce the chance of bacteria growth during transport. The samples remained refrigerated until processed, where they were homogenized and divided into sub-samples for laboratory processing. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Kathryn Smith
    Ecologist
    600 4th Street South
    St. Petersburg, Florida
    USA

    727502-8000 (voice)
    Data sources produced in this process:
    • physical sediment samples
    Date: 2011 (process 2 of 4)
    Laboratory procedure: All surface sediment samples were processed in the laboratory for bulk density, organic carbon (by loss-on-ignition), and grain size. 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 to a fine powder and combusting a subsample at 650 °C for four hours. Approximately 50 percent of the samples were measured in triplicate to calculate sample error. Grain size was measured by laser diffraction using a Coulter LS 200 particle-size analyzer after organic digestion. For organic matter digestion, approximately 5g of sediment was placed in a 50-mL test tube, 15-mL of sodium hypochlorite was added, and placed in a warm water bath (80 °C) for 15 minutes. The sample was then centrifuged and supernatant was carefully removed using a pipette as to not remove sediments. The sodium hypochlorite digestion was conducted at least three times to remove all organic matter. After digestion, 7 percent sodium hexametaphosphate solution was added to deflocculate clays. At minimum, three aliquots were analyzed three times to generate a total of nine grain-size distributions for each sample. Estimates of percent sand, silt, clay and mean phi were calculated from grain size distributions for each aliquot using GRADISTAT version 8. The nine datasets were checked for any unusual variations (for example, exceptionally high or low values which can be caused by partially undigested organics or debris) and data were removed if values deviated significantly from the majority of aliquots (1 standard deviation from the mean). The remaining data were averaged to create a single estimate of grain size (percent sand, silt, and clay, and mean sediment size) for each sample. Data was copied into Microsoft Excel, double-checked for errors, and exported to 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:
    • surface_sediment_properties.txt
    Date: 2011 (process 3 of 4)
    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. Data was copied into Microsoft Excel, double-checked for errors, and exported to 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:
    • surface_sediment_diatoms.txt
    • taxa_list.txt
    Date: 28-Mar-2018 (process 4 of 4)
    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 sample collection, preparation, and analyses. When replicate samples were collected for sediment properties, the standard deviation is provided. Several replicate 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.
  2. How accurate are the geographic locations?
    Expected horizontal accuracy for site surveys is 0.005 to 0.020 meters. http://www.lacoast.gov/crms/doc/ATTACHMENT_3_GPSGUIDE.pdf
  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

    727-8502-8000 (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: 28-Mar-2018
Metadata author:
U.S. Geological Survey
Attn: Kathryn Smith
Ecologist
600 4th Street South
St. Petersburg, FL
USA

727-803-8747 (voice)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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