15CCT02_metadata: Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  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?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Marot, Marci E., Smith, Christopher G., McCloskey, Terrence A., Locker, Stanley D., Khan, Nicole S., and Smith, Kathryn E.L., 20190301, 15CCT02_metadata: Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016: U.S. Geological Survey Data Release doi:10.5066/P9FO8R3Y, U.S. Geological Survey, St. Petersburg, FL.

   Online Links:

   • https://doi.org/10.5066/P9FO8R3Y

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -88.40850
   East_Bounding_Coordinate: -88.35860
   North_Bounding_Coordinate: 30.40980
   South_Bounding_Coordinate: 30.35690
   

3. What does it look like?
4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 29-May-2015

   Ending_Date: 03-Jun-2015

   Currentness_Reference:

   ground condition

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: Multimedia presentation
   

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?

   15CCT02_SiteInformation.xlsx

   Microsoft Excel workbook defining the field sampling dates, site locations, water depths, and water quality parameters for the surficial sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). (Source: USGS)

   15CCT02_SiteInformation.csv

   Comma-separated values text file defining the field sampling dates, site locations, water depths, and water quality parameters for the surficial sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). (Source: USGS)

   15CCT02_SedimentPhysicalProperties.xlsx

   Microsoft Excel workbook listing water content, porosity, bulk density and loss on ignition data for the surficial sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). (Source: USGS)

   15CCT02_SedimentPhysicalProperties.csv

   Comma-separated values text file listing water content, porosity, bulk density and loss on ignition data for the surficial sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). (Source: USGS)

   15CCT02_GrainSize.xlsx

   Microsoft Excel workbook summarizing grain-size parameters for surficial sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). The averaged results for each sample, including the number of runs used, the standard deviation of the averaged results, and graphical class-size distributions, are provided. (Source: USGS)

   15CCT02_GrainSize.csv

   Comma-separated values text file summarizing grain-size parameters for surficial sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). The averaged results for each sample, including the number of runs used, the standard deviation of the averaged results, and graphical class-size distributions, are provided. (Source: USGS)

   15CCT02_AlphaSpectroscopy.xlsx

   Microsoft Excel workbook listing total Pb-210 activities and counting errors for estuarine bottom sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). (Source: USGS)

   15CCT02_AlphaSpectroscopy.csv

   Comma-separated values text file listing total Pb-210 activities and counting errors for estuarine bottom sediment samples collected in this study (USGS FAN 2015-315-FA, project ID 15CCT02). (Source: USGS)

   Site ID

   Site identifier assigned by the USGS scientist (Source: USGS) Character string

   Date Collected

   Calendar date of field sample collection (Source: USGS)

   Range of values
   Minimum:	05/29/2015
   Maximum:	06/03/2015
   Units:	mm/dd/yyyy
   Resolution:	1

   Type of Samples Collected

   Alphabetic identifiers designating field collection methods, assigned by the USGS scientist (Source: USGS) Character string

   Latitude (WGS84)

   Latitude of site location relative to the World Geodetic System 1984, in decimal degrees (Source: Garmin)

   Range of values
   Minimum:	30.35684
   Maximum:	30.41776
   Units:	Decimal degree
   Resolution:	0.00001

   Longitude (WGS84)

   Longitude of site location relative to the World Geodetic System 1984, in decimal degrees (Source: Garmin)

   Range of values
   Minimum:	-88.40844
   Maximum:	-88.31331
   Units:	Decimal degree
   Resolution:	0.00001

   Water Depth (m)

   Water column depth at the estuarine sampling sites, in meters (Source: USGS)

   Range of values
   Minimum:	0.0
   Maximum:	3.4
   Units:	Meter
   Resolution:	0.1

   Temperature (°C)

   Water temperature at each sampling site, in degrees Celsius (Source: YSI)

   Range of values
   Minimum:	27.1
   Maximum:	30.1
   Units:	Degree Celsius
   Resolution:	0.1

   Barometric Pressure (mmHg)

   Barometric pressure at each sampling site, in millimeters of mercury (Source: YSI)

   Range of values
   Minimum:	761.0
   Maximum:	766.6
   Units:	Millimeters of mercury
   Resolution:	0.1

   Dissolved Oxygen (%)

   Water column percent dissolved oxygen at each sampling site (Source: YSI)

   Range of values
   Minimum:	57.9
   Maximum:	109.5
   Units:	Percent
   Resolution:	0.1

   Dissolved Oxygen (mg/L)

   Water column dissolved oxygen at each sampling site, in milligrams per liter (Source: YSI)

   Range of values
   Minimum:	4.13
   Maximum:	7.77
   Units:	Milligrams per liter
   Resolution:	0.01

   Specific Conductance (mS/cm)

   Water column specific conductance at each sampling site, in millisiemens per centimeter (Source: YSI)

   Range of values
   Minimum:	5.08
   Maximum:	29.37
   Units:	Millisiemens per centimeter
   Resolution:	0.01

   Salinity

   Water column salinity at each sampling site (Source: YSI)

   Range of values
   Minimum:	2.72
   Maximum:	18.08
   Units:	Practical salinity unit
   Resolution:	0.01

   pH

   Water column pH at each sampling site (Source: YSI)

   Range of values
   Minimum:	6.24
   Maximum:	8.12
   Units:	Hydrogen ion concentration
   Resolution:	0.01

   Oxidation-Reduction Potential (mV)

   Water column oxidation-reduction potential, in millivolts, at each sampling site (Source: YSI)

   Range of values
   Minimum:	73.5
   Maximum:	189.4
   Units:	Millivolt
   Resolution:	0.1

   Sample ID

   Individual sample identifier assigned by the USGS scientist (Source: USGS) Character string

   Water Content (g-water/g-wet)

   The ratio of the mass of water to the mass of wet sediment (Source: USGS)

   Range of values
   Minimum:	0.22
   Maximum:	0.62
   Units:	Grams of water per grams of wet sediment
   Resolution:	0.01

   Porosity (cm^3-voids/cm^3-wet)

   Porosity of the sediment interval (Source: USGS)

   Range of values
   Minimum:	0.41
   Maximum:	0.80
   Units:	Cubic centimeter of void space per cubic centimeter of wet sediment
   Resolution:	0.01

   Dry Bulk Density (g/cm^3)

   Dry bulk density of the sediment interval (Source: USGS)

   Range of values
   Minimum:	0.35
   Maximum:	1.38
   Units:	Grams per cubic centimeter
   Resolution:	0.01

   Loss On Ignition (g-OM/g-dry)

   The ratio of the mass of organic matter combusted at 550 Celsius to the pre-combusted mass of dry sediment (Source: USGS)

   Range of values
   Minimum:	0.005
   Maximum:	0.350
   Units:	Grams of organic matter per grams of dry sediment
   Resolution:	0.001

   Total Pb-210 (dpm/g)

   Total Pb-210 specific activity measured in disintegrations per minute per gram of dry sediment (Source: USGS)

   Range of values
   Minimum:	0.79
   Maximum:	1.52
   Units:	Disintegrations per minute per gram
   Resolution:	0.01

   Total Pb-210 Error (+/- dpm/g)

   Total Pb-210 specific activity counting error measured in disintegrations per minute per gram of dry sediment (Source: USGS)

   Range of values
   Minimum:	0.018
   Maximum:	0.021
   Units:	Disintegrations per minute per gram
   Resolution:	0.001

   Entity_and_Attribute_Overview:

   The detailed attribute descriptions for the grain size workbook are provided in the included data dictionary (15CCT02_Grain_Size_Data_Dictionary.pdf). These metadata are not complete without this file.

   Entity_and_Attribute_Detail_Citation:

   Data dictionary for grain-size data tables, in: Marot, M.E., Smith, C.G., McCloskey, T.A., Locker, S.D., Khan, N.S., and Smith, K.E.L., 2019, Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016: U.S. Geological Survey data release, https://doi.org/10.5066/P9FO8R3Y.

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Marci E. Marot
   • Christopher G. Smith
   • Terrence A. McCloskey
   • Stanley D. Locker
   • Nicole S. Khan
   • Kathryn E.L. Smith
2. Who also contributed to the data set?
   U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center
3. To whom should users address questions about the data?
   U.S. Geological Survey

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   mmarot@usgs.gov

Why was the data set created?

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: 2015 (process 1 of 8)

   At 32 sites within the marsh tidal channels and Grand Bay proper, estuarine bottom sediments were collected with a petite ponar grab sampler. The sediment recovered in the grab sampler was inspected for an undisturbed sediment-water interface. If the sediment was disturbed, the sediment was discarded and a new grab sample was collected. If the sediment surface was intact, the overlying water was gently removed, and the uppermost one centimeter (cm) of sediment was sampled for sediment characterization. Water quality properties at each site were measured with an YSI Professional Plus multi-sensor meter. At most sites, 5 gallons of the tidal channel or bay water was filtered through manganese dioxide-coated acrylic fiber to extract radium radioisotopes. The radium radioisotopic analytical results are not presented in this report. Surface and water sample identifiers consist of the USGS project ID (15CCT02) and a site-specific identifier (for example, GB101). An alphabetic identifier was appended to each site identifier to differentiate the collection method (B for Mn-fiber radium samples and G for bottom sediment grab samples). The site position was recorded with a vessel-mounted Garmin ECHOMAP 50s or a hand-held Garmin GPSMAP 62stc GPS receiver. Site locations, date of collection, and YSI measurements are reported in an Excel spreadsheet. Comma-separated values data files containing the tabular data in plain text are included in the download files. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Data sources produced in this process:

   • 15CCT02_FieldLogs.pdf
   • 15CCT02_SiteInformation.zip

   Date: 2015 (process 2 of 8)

   At five sites within Grand Bay marsh, the uppermost 1 cm of surficial sediment was collected for sediment characterization. Pore water quality properties at site GB173 were measured with an YSI Professional Plus multi-sensor meter in an excavated hole which naturally in-filled with ground water. Surface sample identifiers consist of the USGS project ID (15CCT02) and a site-specific identifier (for example, GB170). An alphabetic identifier was appended to each site identifier to differentiate the collection method (S for surface sample). The site positions for GB170-GB172 were recorded with a hand-held Garmin GPSMAP 62stc receiver. The site positions for GB173 and GB174 were taken from the GPS data embedded in the digital photographic image of the sampling location captured with a Nikon Coolpix AW100 camera with built-in GPS receiver. Site locations, elevations, date of collection, and YSI measurements are reported in an Excel spreadsheet. Comma-separated values data files containing the tabular data in plain text are included in the download files. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Data sources produced in this process:

   • 15CCT02_FieldLogs.pdf
   • 15CCT02_SiteInformation.zip

   Date: 2015 (process 3 of 8)

   In the SPCMSC laboratory, the surficial sediment grab samples (G & S samples) were processed for basic sediment characteristics (dry bulk density and porosity). Water content, porosity and dry bulk density were determined using water mass lost during drying. For each 1-cm interval, 13–120 milliliters (mL) of each wet subsample was packed into a graduated syringe with 0.5 mL resolution. The wet sediment was then extracted into a pre-weighed aluminum tray and the weight of the wet sediment and the volume was recorded. The wet sediment and tray were placed in a drying oven for a minimum of 48 hours at 60 degrees Celsius (°C). Water content (θ) was determined as the mass of water (mass lost when dried) relative to the initial wet sediment mass. Dry bulk density was determined by ratio of dry sediment to the known volume of sediment packed into the syringe. Porosity (φ) was calculated from the equation φ = θ / [θ+(1-θ)/ρs] where ρs is grain density assumed to be 2.5 grams per cubic centimeter (g/cm^3). Salt-mass contributions were removed based on the salinity measured at the time of sample collection. Salinity for the marsh surface sites was estimated to be 2.72, which was the salinity measured at site GB173. Water content, porosity and dry bulk density are reported in the Excel spreadsheet. A comma-separated values data file containing the tabular data in plain text is included in the download file. Person who carried out this activity:
   

   U.S. Geological Survey St. Petersburg Coastal and Marine Science Center

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   U.S.

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Data sources produced in this process:

   • 15CCT02_SedimentPhysicalProperties.zip

   Date: 2015 (process 4 of 8)

   Organic matter content was determined with a mass loss technique, referred to as loss on ignition (LOI). The dry sediment from the previous process was homogenized with a porcelain mortar and pestle. Approximately 5 grams (g) of the dry sediment was placed into a pre-weighed porcelain crucible. The mass of the dried sediment was recorded. The sample was then placed inside a laboratory muffle furnace with stabilizing temperature control. The furnace was heated to 110 °C for a minimum of 6 hours to remove hygroscopic water absorbed onto the sediment particles. The furnace temperature was then lowered to 60 °C, at which point the sediments could be reweighed. The dried sediment was returned to the muffle furnace. The furnace was heated to 550 °C over 30 minutes and kept at 550 °C for 6 hours. The furnace temperature was then lowered to 60 °C and held at this temperature until the sediments could be reweighed. The latter step prevents the absorption of moisture, which can affect the measurement. The mass lost during the 6-hour baking period relative to the 110 °C-dried mass is used as a metric of organic matter content. Data are reported as a ratio of mass (g) of organic matter to mass (g) of dry sediment (post-110 °C drying). Loss on ignition measurements are reported for in the Excel spreadsheet. A comma-separated values data file containing the tabular data in plain text is included in the download file. Person who carried out this activity:
   

   U.S. Geological Survey St. Petersburg Coastal and Marine Science Center

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   U.S.

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Data sources produced in this process:

   • 15CCT02_SedimentPhysicalProperties.zip

   Date: 2015 (process 5 of 8)

   Particle size analysis was performed on the 37 surficial sediment (G & S) samples. Prior to particle size analysis, organic material was chemically removed from the samples using 30% hydrogen peroxide (H2O2). Wet sediment was dissolved in H2O2 overnight. The H2O2 was then evaporated by gentle heating and the sediment washed and centrifuged twice with deionized water. Grain size analyses on the sediment cores were performed using a Coulter LS 200 (https://www.beckmancoulter.com/) particle-size analyzer (PSA), which uses laser diffraction to measure the size distribution of sediments ranging in size from 0.4 microns to 2 millimeters (mm) (clay to very coarse-grained sand). To prevent shell fragments from damaging the Coulter instrument, particles greater than 1 mm in diameter were separated from all samples prior to analysis using a number 18 (1000 microns or 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. Two subsamples from each depth interval were processed through the instrument a minimum of three runs each. The sediment slurry made from the digested sample and deionized water was sonicated with a wand sonicator for 1 minute before being introduced into the Coulter PSA to breakdown aggregated particles. The Coulter PSA measures 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 based on the ASTM E11 standard. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Date: 2015 (process 6 of 8)

   The raw grain size data were then run through the free software program GRADISTAT (Blott and Pye, 2001; http://www.kpal.co.uk/gradistat), which calculates the mean, sorting, skewness, and kurtosis of each sample geometrically in metric units and logarithmically in phi units. GRADISTAT also calculates the fraction of sediment from each sample by size category (for example, clay, coarse silt, fine sand). A macro function in Microsoft Excel, developed by the USGS SPCMSC, was applied to the data to calculate average and standard deviation for each sample set (6-8 runs per sample), and highlight runs that varied from the set average by more than ±1.5 standard deviations. Excessive deviations from the mean are likely the result of equipment error or extraneous organic material in the sample and are not considered representative of the sample. The highlighted runs were removed from the results and the sample average was recalculated using the remaining runs. The averaged results for all samples, including the number of averaged runs and the standard deviation of the averaged results were summarized in an Excel workbook. A comma-separated values data file containing the tabular data in plain text is included in the download file. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Data sources produced in this process:

   • 15CCT02_GrainSize.zip

   Date: 2016 (process 7 of 8)

   Total Pb-210 activity was measured by alpha spectroscopy for 7 estuarine bottom sediment grab samples. The Pb-210 (half-life = 22.3 years) activity is determined by directly measuring the activity of its granddaughter Po-210 (half-life = 138 days) via alpha particle decay. Po-210 is assumed to be in secular equilibrium with its parent. The analytical method exploits the ability of polonium to self­plate onto silver planchets, which facilitates the alpha counting (Flynn, 1968). The laboratory method used at the USGS SPSMSC for chemical separation of Po-210 from sediments was developed by Martin and Rice (1981). Po-210 was acid leached from 5 grams of dried, ground sediment with concentrated nitric acid and a known activity of the tracer Po-209 was added to the solution. The solution digested overnight and then was dried on a hotplate, followed by a series of washings with 30% hydrogen peroxide and 8N hydrochloric acid. The final acidic solution was brought to 70 mL with deionized water. Several buffering solutions were added to reduce interference from other cations and oxidants present during the plating process. The pH was adjusted to between 1.8-1.9 with ammonium hydroxide. The Po-210 was autoplated onto 1.9-cm diameter sterling silver planchets while stirring and heating the solution. After 2 hours, the planchets were removed from solution, rinsed and dried. The planchets were counted for 24 hours in low-level alpha spectrometers coupled to a pulse-height analyzer equipped with silicon surface barrier detectors. The radioisotopic activities reported in the Excel spreadsheet include the counting error for all samples. A comma-separated values data file containing the tabular data in plain text is included in the download file. Person who carried out this activity:
   

   U.S. Geological Survey St. Petersburg Coastal and Marine Science Center

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   U.S.

   (727) 502-8000 (voice)

   mmarot@usgs.gov

   Data sources produced in this process:

   • 15CCT02_AlphaSpectroscopy.zip

   Date: 13-Oct-2020 (process 8 of 8)

   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?
   DeWitt, N.T., Stalk, C.A., Smith, C.G., Locker, S.D., Fredericks, J.J., McCloskey, T.A., and Wheaton, C.J., 2017, Single-beam bathymetry data collected in 2015 from Grand Bay, Alabama-Mississippi: U.S. Geological Survey Data Series 1070.

   Online Links:

   • https://doi.org/10.3133/ds1070

   Stalk, C.A., Fredericks, J.J., Locker, S.D., and Carlson, C.S., 2018, Multibeam bathymetry data collected in 2016 from Grand Bay Alabama/Mississippi: U.S. Geological Survey data release doi.org/10.5066/F7MC8Z9N.

   Online Links:

   • https://doi.org/10.5066/F7MC8Z9N

   Locker, S.D., Forde, A.S., and Smith, C.G., 2018, Subbottom and sidescan sonar data acquired in 2015 from Grand Bay, Mississippi and Alabama: U.S. Geological Survey data release doi.org/10.5066/P9374DKQ.

   Online Links:

   • https://doi.org/10.5066/P9374DKQ

   Haller, Christian, Osterman, L.E., Smith, C.G., McCloskey, T.A., Marot, M.E., Ellis, A.M., and Adams, C.S., 2018, Benthic foraminiferal data from the eastern Mississippi Sound salt marshes and estuaries: U.S. Geological Survey data release doi.org/10.5066/F7MC8X5F.

   Online Links:

   • https://doi.org/10.5066/F7MC8X5F

   Haller, Christian, Smith, C.G., McCloskey, T.A., Marot, M.E., Ellis, A.M., and Adams, C.S., 2018, Benthic foraminiferal data from sedimentary cores collected in the Grand Bay (Mississippi) and Dauphin Island (Alabama) salt marshes: U.S. Geological Survey data release doi.org/10.5066/F7445KSG.

   Online Links:

   • https://doi.org/10.5066/F7445KSG

   Blott, S.J. and Pye, K., 2001, Gradistat: A grain size distribution and statistics package for the analysis of unconsolidated sediments: Earth Surface Processes and Landforms Volume 26.

   Online Links:

   • http://www.kpal.co.uk/gradistat.html

   Other_Citation_Details: Pages 1237-1248
   

   Flynn, W.W., 1968, The determination of low levels of polonium-210 in environmental materials: Analytica Chimica Acta Volume 43.

   Other_Citation_Details: Pages 221-227
   

   Martin, E.A., and Rice, C.A., 1981, Sampling and analyzing sediment cores for 210Pb geochronology: U.S. Geological Survey Open-File Report 81-893.

   Online Links:

   • https://pubs.er.usgs.gov/publication/ofr81983

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

1. How well have the observations been checked?
   The positional accuracy of the sample locations was determined by the accuracy of the vessel-mounted Garmin ECHOMAP 50s or hand-held Garmin GPSMAP 62stc Global Positioning System (GPS) receiver used to record the sample sites during the time of collection. The grain size data represent the sample averages for a subset of the statistical parameters calculated by GRADISTAT. The number of runs included in the averaged results are reported, and the standard deviation of the averaged results are reported for most parameters.
2. How accurate are the geographic locations?
   Sample locations in the Grand Bay estuary were recorded at the time of collection using a vessel-mounted Garmin ECHOMAP 50s GPS receiver located amidship of the 17-foot USGS R/V Mako or a hand-held Garmin GPSMAP 62stc GPS receiver. The actual core sites were offset from the center of the boat by up to 8 feet.
3. How accurate are the heights or depths?
   Surface elevations of the estuarine bottom sediments were determined as depth below water level.
4. Where are the gaps in the data? What is missing?
   This dataset is considered complete for the information presented, as described in the abstract section. Users are advised to read the rest of the metadata record carefully for additional details.
5. How consistent are the relationships among the observations, including topology?
   The grain-size sample runs in the GRADISTAT output files for which the mean Folk and Ward grain size varied from the set average by more than 1.5 standard deviations are highlighted in yellow and were not included in final averaged results. No formal logical accuracy tests were conducted on the remaining datasets. Counting errors are reported for the radioisotope alpha spectroscopy data based on the time-dependent detection rate and efficiency of the pulse-height analyzer.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center

   Attn: Marci E. Marot

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   mmarot@usgs.gov
2. What's the catalog number I need to order this data set? Downloadable data
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, or for general or scientific purposes, 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:	These zip archives includes Microsoft Excel spreadsheets, comma-separated values text files, Portable Document Format (PDF) image files, and accompanying metadata for sediment data from surficial sediments collected from Grand Bay, Alabama/Mississippi in May-June 2015 (USGS FAN 2015-315-FA, project ID 15CCT02). in format Compressed (zip) archive Multimedia presentation
     Network links:	https://coastal.er.usgs.gov/data-release/doi-P9FO8R3Y/data/15CCT02_FieldLogs.pdf

   • Cost to order the data: None, if obtained online

5. What hardware or software do I need in order to use the data set?
   The data tables for USGS FAN 2015-315-FA (project ID 15CCT02) were created in Microsoft Excel 2010 and can be opened using Microsoft Excel 2007 or higher; these data may also be viewed using the free Microsoft Excel Viewer (http://office.microsoft.com/). The data tables are also provided as comma-separated values text files (.csv). The .csv data file contains the tabular data in plain text and may be viewed with a standard text editor. Portable Document Format (PDF) files can be viewed using the free software Adobe Acrobat Reader (http://get.adobe.com/reader).

Who wrote the metadata?

Dates:

Last modified: 03-Nov-2023

Metadata author:

U.S. Geological Survey

Attn: Marci E. Marot

Geologist

600 4th Street South

St. Petersburg, FL

USA

727-502-8000 (voice)

mmarot@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)