Sediment data collected in July 2014 from around Breton and Gosier Islands, Louisiana (U.S. Geological Survey Field Activity Numbers 2014–314–FA and 14BIM04)

USGS scientists collected 18 push cores and 38 submerged grab samples collected from around Breton and Gosier Islands in July 2014 (USGS FANs 2014-314-FA and 14BIM04). Grab samples were collected using a WILDCO Petit Ponar grab sampler. Push cores were collected using an AMS sand/loose sediment soil probe lined with a 2.54-centimeter (cm) (1-inch) diameter by approximately 60-cm (2-foot) long plastic sleeve. After extraction, each core was capped, sealed, and labeled with transect location, core number, and orientation. The cores were transported to the USGS SPCMSC sediment lab for processing and analysis.

Sample locations were recorded at the time of collection using a Garmin GPSMAP 76S handheld GPS receiver along with a physical description of each sample site. At the core sites, position and elevation data were also recorded with an Ashtech DGPS receiver and antenna, which provided more accurate horizontal and vertical control than handheld GPS systems.DGPS data were recorded concurrently throughout the survey using a similar instrument combination at a base station located at a previously installed USGS benchmark (BRET) on the northwest end of Breton Island within 15 km of the farthest sample site. An Ashtech Proflex GPS receiver recorded the 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via a Thales choke-ring antenna at the base station. A similar GPS instrument combination (Ashtech Z-Xtreme receiver and Ashtech geodetic antenna) was used for the rover GPS. The base receiver and the rover receiver record their positions concurrently at 0.1- to 1-second (s) recording intervals throughout the survey. A stop-and-go rapid-static survey technique was used, with a static occupation duration of 5 minutes at each sample site.

The coordinate values of the GPS base station (BRET) are the time-weighted average of values obtained from OPUS. The base station coordinates were imported into GrafNav, version 8.50 (Waypoint Product Group) and the data from the rover GPS (the GPS unit used to collect data at each push-core site) were post-processed to the concurrent base-station session data; baseline distances for all push-core sites were less than 15 km. The GPS data were acquired and processed in the World Geodetic System of 1984 (WGS84) (G1150) geodetic datum.

Using the National Geodetic Survey (NGS) transformation software packages HTDP (http://www.ngs.noaa.gov/TOOLS/Htdp/Htdp.shtml), version 3.2.3 and VDatum, version 3.3 (http://vdatum.noaa.gov/), the sample locations were transformed from the GPS acquisition datum (WGS84) to the North American Datum of 1983 (NAD83), Universal Transverse Mercator (UTM) Zone 16 north (16N) reference frame and the North American Vertical Datum of 1988 (NAVD88) orthometric elevation using the NGS geoid model of 2012(A) (GEOID12A).

Surface elevations for grab-sample sites at which DGPS data were not collected were extracted from a 100-meter by 100-meter gridded surface of USGS bathymetric data collected in July 2014 (DeWitt and others, 2016) using the Spatial Analyst Extract Values to Points tool in Esri ArcGIS version 10.2.

At the SPCMSC sediment laboratory, the push cores were x-rayed using an Ecotron EPX-F2800 x-ray unit at 85 kilovolts for 16 milliampere-seconds from a height of 79 cm. The x-radiograph was captured on an 11 × 14-inch phosphor cassette, which was scanned on an iCRco, Inc., iCR3600+ scanner at 254 pixels per inch and exported as a 16-bit Tagged Image File Format (TIFF) image. The raw x-radiographs show a slight anode heel effect, which is a variation in x-ray intensity along the anode-cathode axis that results in non-uniform pixel intensity across the image. This effect was corrected by subtracting a background pixel intensity template from each raw image. The anode heel effect has been mostly removed from the filtered images, and variations in the down-core pixel intensity correspond to variations in lamination densities and can be compared against other cores. Cores longer than approximately 35 cm, that did not fit onto the phosphor cassette or extended into the area at the bottom of the x-radiograph where the filter could not completely remove the heel effect, were x-rayed in "top" and "bottom" segments and then merged in Adobe Photoshop Creative Cloud (CC) 2014. Images were then edited in Adobe Photoshop CC 2014 by applying a grayscale color inversion. Core-photo file names reflect this process lineage (CoreID_filt_invert.tiff or CoreID_filt_merged_invert.tiff). Each push core was then split lengthwise, photographed, described macroscopically using standard sediment-logging methods, and subsampled at 2-cm intervals for grain-size analysis. In addition to whole-core photographs (CoreID.jpg), which were taken with a Canon Powershot SX20 IS digital camera, the cores were also photographed in approximately 5-cm, overlapping segments with a Nikon COOLPIX P5000 digital camera using the macro focus mode from a fixed height. The raw images were "stitched" together using The Panorama Factory version 5.3 software, providing seamless high-resolution whole-core images (CoreID_sc_adj.jpg). Textural descriptions for the core logs are based on macroscopic observations; the quantitative grain-size data are represented by down-core plots on the core logs. Sediment color is based on the Munsell soil color system.

Grain-size analyses were performed using Coulter LS 200 (grab samples) and Coulter LS 13 320 (push cores) particle-size analyzers, which use laser diffraction to measure the size distribution of sediments ranging in size from 0.4 microns (µm) to 2 millimeters (mm) (clay to very coarse-grained sand). A total of 178 samples from 18 cores and 38 grab samples were analyzed. Core samples consisted of 2-cm sections of the core based on the minimum amount of material needed for analysis. In order to prevent shell fragments from damaging the Coulter analyzers, particles greater than 1 mm in diameter were separated from all samples prior to analysis using a number 18 (1000 µm, 1 mm) U.S. standard sieve, which meets the American Society for Testing and Materials (ASTM) E11 standard specifications for determining particle size using woven-wire test sieves. Prior to sieving, each down-core sample was dried at 60 degrees Celsius for 24 hours, and the fraction of sediment greater than 1 mm was recorded as a percentage of the bulk sample dry weight. Two subsamples from each sample were processed through the LS 200 or the LS 13 320 particle-size analyzers a minimum of three runs each. These instruments measure the particle-size distribution of each sample by passing sediment suspended in solution between two narrow panes of glass in front of a laser. Light is scattered by the particles into characteristic refraction patterns measured by an array of photodetectors as intensity per unit area and recorded as relative volume for 92 size-related channels (bins). The size-classification boundaries for each bin were specified on the basis of the ASTM E11 standard.

The raw grain-size data were run through the free, widely available program GRADISTAT (Blott and Pye, 2001), which calculates the geometric (in metric units) and logarithmic (in phi units, Φ; Krumbein, 1934) mean, sorting, skewness, and kurtosis of each sample using the Folk and Ward (1957) method as well as the cumulative particle-size distribution. GRADISTAT also calculates the fraction of sediment from each sample by size category (for example, clay, coarse silt, fine sand) based on a modified Wentworth (1922) size scale. A macro developed by the USGS was applied to calculate the average and standard deviation of each sample (six runs per sample) and highlight runs that varied from the set average by more than plus or minus (±) 1.5 standard deviations. Excessive deviations from the mean are likely the result of equipment error or extraneous material in the sample and are not considered representative of the sample. Those runs were removed from the results and the sample average was recalculated using the remaining runs. The individual run statistics are available from https://coastal.er.usgs.gov/data-release/doi-F79C6VKF/data/14BIM04_GrainSize_RunStats.zip. The averaged results for all samples, including the number of runs used, the standard deviation of the averaged results, and class-size distributions, are summarized in a series of Excel workbooks with each core on its own tab and are available from https://coastal.er.usgs.gov/data-release/doi-F79C6VKF/data/14BIM04_GrainSize_SumStats.zip.

Using Exchangeable image file format (Exif) data, the GPS date, time and coordinates recorded during sediment core collection were embedded in the whole-core (CoreID.jpg) and stitched (CoreID_sc_adj.jpg) image metadata. The Exif headers were initially populated by the camera’s imaging software but were subsequently updated by USGS staff to include core-related supplemental information. A Python version 2.7.3 script (UpdatePhotoEXIFv2.py) was run to incorporate location information and auxiliary details into the appropriate locations within the Exif header of each full-resolution JPEG image. The Python script used ExifTool version 10.25 to write the information to the image headers. The following tags were populated in the JPEG image headers. Information is duplicated in some tags. This was done because different software packages access different tags.
GPS tags: The values populated are unique for each image and based on the information exported from the handheld GPS.

GPSLatitudeRef
GPSLatitude
GPSLongitudeRef
GPSLongitude
GPSTimeStamp
GSPDateStamp

JPEG tags: The tag is listed along with the information used to populate it - which is the same for every image taken with a particular camera. The following information is based on the Canon PowerShot SX20 IS camera.

comment: Photo of core collected in July 2014 from Breton and Gosier Islands, Louisiana during field activity number 2014–314–FA, alternate FAN 14BIM04 (https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-314-FA). Published as USGS data release DOI:10.5066/F79C6VKF.

EXIF tags: The tag is listed along with the information used to populate it - which is the same for every image.

ImageDescription: Photograph of sediment core collected from Breton National Wildlife Refuge, LA during 2014–314–FA.

Artist: U.S. Geological Survey
Copyright: Public Domain - please credit U.S. Geological Survey

IPTC tags: The tag is listed along with the information used to populate it - which is the same for every image.

Credit: U.S. Geological Survey
Contact: gs-g-spcmsc_data_inquiries@usgs.gov
Keywords: Breton National Wildlife Refuge, Louisiana, Breton Island, Gosier Island, 2014–314–FA, 14BIM04, push-core, grab sample, vibracore, USGS
CopyrightNotice: Public Domain - please credit U.S. Geological Survey
Caption-Abstract: Photograph of sediment core collected from Breton National Wildlife Refuge, LA during 2014–314–FA.

XMP tags: The tag is listed along with the information used to populate it - which is the same for every image.

Caption: Photograph of sediment core collected from Breton National Wildlife Refuge, LA during 2014–314–FA.

To extract the information from the image headers using ExifTool, the following command can be used (tested with ExifTool version 10.25):

exiftool.exe -csv -f -filename -GPSTimeStamp -GPSLongitude -GPSLatitude -n -Artist -Credit -comment -keywords -Caption -Copyright -CopyrightNotice -Caption-Abstract -ImageDescription photos/*.jpg > out.csv

The -csv flag writes the information out in a comma-delimited format. The -n option formats the latitude and longitude as signed decimal degrees.

Added keywords section with USGS persistent identifier as theme keyword.