Location and analyses of sediment samples collected on Stellwagen Bank off Boston, Massachusetts from September 2020 to August 2021 during three U.S. Geological Survey field activities

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What does this data set describe?

1. How might this data set be cited?
   Valentine, Page C., 20230321, Location and analyses of sediment samples collected on Stellwagen Bank off Boston, Massachusetts from September 2020 to August 2021 during three U.S. Geological Survey field activities: data release DOI:10.5066/P9G7QARQ, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P9G7QARQ
   • https://sciencebase.gov/catalog/item/633c99a1d34e900e86cf1ab7

   This is part of the following larger work.
   Valentine, Page C., and Cross, VeeAnn A., 2023, Sea-floor Sediment Samples, Seabed and Sample Imagery, and CTD Instrument Data Collected on Stellwagen Bank from September 2020 to August 2021: data release DOI:10.5066/P9G7QARQ, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9G7QARQ
   • https://sciencebase.gov/catalog/item/633c8e2dd34e900e86cf1a93

   Other_Citation_Details:

   Suggested citation: Valentine, P.C., and Cross, V.A., 2023, Sea-floor sediment samples, seabed and sample imagery, and CTD instrument data collected on Stellwagen Bank from September 2020 to August 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P9G7QARQ .

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.56265
   East_Bounding_Coordinate: -70.11801
   North_Bounding_Coordinate: 42.43998
   South_Bounding_Coordinate: 42.09603
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/633c99a1d34e900e86cf1ab7?name=stellwagen_2020_2021_sedsamps_browse.jpg&allowOpen=true (JPEG)

   Browse graphic of the sediment sample locations collected on Stellwagen Bank.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 24-Sep-2020

   Ending_Date: 04-Aug-2021

   Currentness_Reference:

   Ground condition of when data were collected. These data were collected during three separate surveys, with the following ranges of dates for each survey: field activity 2020-012-FA: 20200924 to 20200925; field activity 2021-016-FA: 20210721 to 20210723; and field activity 2021-017-FA: 20210802 to 20210804.

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):
      • Point (137)
   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 0.000001. Longitudes are given to the nearest 0.000001. 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 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
      

      Vertical_Coordinate_System_Definition:

      Depth_System_Definition:

      Depth_Datum_Name: Local surface
      Depth_Resolution: 1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
      

7. How does the data set describe geographic features?

   stellwagen_2020_2021_sedsamps.xlsx

   Sediment sample location and analyses in Excel spreadsheet format. The attributes defined refer to the Excel spreadsheet column headings, and are also in the header row of the CSV file. The shapefile has these attributes (except ANALYSIS_I instead of ANALYSIS_ID, CLASSIFICA instead of CLASSIFICATION, and QUALITY_GR instead of QUALITY_GRADE), and the software generated FID and shape, defined in the entity and attribute overview section. These last two shapefile specific attributes are not visible in all GIS software packages. The last Excel spreadsheet column is omitted from the CSV and shapefile and is described in the entity and attribute overview section. (Source: U.S. Geological Survey)

   ANALYSIS_I

   Truncated from the spreadsheet ANALYSIS_ID. An identifier for the sample which is unique to the database. This identifier begins with the assigned multi-letter code GS-, which corresponds to the type of analysis performed on the sample (grain size analysis), followed by a six-digit number assigned sequentially as samples are registered for analysis. (Source: U.S. Geological Survey) Character string.

   FIELD_NO

   Sample name or number as assigned in the field by the Chief Scientist. (Source: USGS East Coast Sediment Texture Database data dictionary) Character string.

   PROJECT

   Name of project or project number under which samples were taken or data generated; sometimes project name indicates a more specific area. (Source: USGS East Coast Sediment Texture Database data dictionary) Character string.

   CRUISE_ID

   Name or number of the cruise on which the sample was collected. The cruise identifier is in the format YYYY-XXX-FA where YYYY is the survey year, XXX is the survey number of that year, and FA indicates field activity. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string.

   CONTACT

   Name of Principal Investigator or Chief Scientist responsible for data collection (usually first initial and last name) when available. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string.

   AREA

   General geographic area of data collection. Name is general enough to easily locate area on a state map. (Source: USGS East Coast Sediment Texture Database data dictionary) Character string.

   LATITUDE

   Latitude coordinate, in decimal-degrees, of sample location. South latitude recorded as negative values. The value is supplied to the lab by the person submitting the sample, so may vary in number of decimal places. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	42.09603
   Maximum:	42.43998
   Units:	Decimal degrees

   LONGITUDE

   Longitude coordinate, in decimal degrees, of sample location. West longitude is recorded as negative values. The value is supplied to the lab by the person submitting the sample, so may vary in number of decimal places. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	-70.56265
   Maximum:	-70.11801
   Units:	Decimal degrees

   DEPTH_M

   Measured depth, in meters, of water overlying sediment sample. The value is supplied to the lab by the person submitting the sample, so may vary in number of decimal places. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	23
   Maximum:	67
   Units:	meters

   T_DEPTH

   Top depth of sample, in centimeters, below the sediment-water interface. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	0
   Units:	centimeters

   B_DEPTH

   Bottom depth of sample, in centimeters, below the sediment-water interface. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	2
   Maximum:	2
   Units:	centimeters

   DEVICE

   Device used to collect the sample. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Value	Definition
   Mini Seaboss w/ 0.1 sq m Van Veen grab	sample collected with the SEABOSS system that uses the 0.1 square meter Van Veen grab.

   MONTH_COLL

   Calendar month sample collected. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	7
   Maximum:	9

   DAY_COLL

   Calendar day sample collected. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	2
   Maximum:	25

   YEAR_COLL

   Calendar year sample collected. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	2020
   Maximum:	2021

   MONTH_ANAL

   Calendar month sample completed analysis. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	5
   Maximum:	8

   DAY_ANAL

   Calendar day sample completed analysis. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	18
   Maximum:	27

   YEAR_ANAL

   Calendar year sample completed analysis. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	2021
   Maximum:	2022

   WEIGHT

   Weight of dry sample in grams. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	44.35
   Maximum:	136.91
   Units:	grams

   GRAVEL_PCT

   Gravel content in percent dry weight of the sample (particles with nominal diameters greater than 2 mm; -1 phi and larger). (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	72.24
   Units:	weight percent
   Resolution:	0.01

   SAND_PCT

   Sand content in percent dry weight of the sample (particles with nominal diameters less than 2 mm, but greater than or equal to 0.0625 mm; 0 phi through 4 phi). (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	25.41
   Maximum:	99.82
   Units:	weight percent
   Resolution:	0.01

   SILT_PCT

   Silt content in percent dry weight of the sample (particles with nominal diameters less than 0.0625 mm, but greater than or equal to 0.004 mm; 5 phi through 8 phi, inclusive). (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.03
   Maximum:	14.35
   Units:	weight percent
   Resolution:	0.01

   CLAY_PCT

   Clay content in percent dry weight of the sample (particles with nominal diameters less than 0.004 mm; less than 8 phi). (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	4.51
   Units:	weight percent
   Resolution:	0.01

   CLASSIFICA

   Truncated from CLASSIFICATION. Sediment description based on rigorous definition usually Shepard (1954) as modified by Schlee and Webster (1967), Schlee (1973), and Poppe and others (2014). These values represent all the possible values as defined in the USGS East Coast Sediment Texture Database data dictionary, and do not necessarily reflect the values present in this dataset. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Value	Definition
   GRAVEL	gravel equal to or greater than 50 percent
   GRAVELLY SEDIMENT	gravel equal to or greater than 10 percent, but less than 50 percent
   SAND	sand equal to or greater than 75 percent
   SILTY SAND	sand less than 75 percent and equal to or greater than 50 percent, silt greater than clay, and clay less than 20 percent
   CLAYEY SAND	sand less than 75 percent and equal to or greater than 50 percent, clay greater than silt, and silt less than 20 percent
   SILT	silt equal to or greater than 75 percent
   SANDY SILT	silt less than 75 percent and equal to or greater than 50 percent, sand greater than clay, and clay less than 20 percent
   CLAYEY SILT	silt less than 75 percent and equal to or greater than 50 percent, clay greater than sand, and sand less than 20 percent
   CLAY	clay equal to or greater than 75 percent
   SANDY CLAY	clay less than 75 percent and equal to or greater than 50 percent, sand greater than silt, and silt less than 20 percent
   SILTY CLAY	clay less than 75 percent and equal to or greater than 50 percent, silt greater than sand, and sand less than 20 percent
   SAND SILT CLAY	clay, sand, and silt greater than 20 percent each

   MEDIAN

   Middle point in the grain size distribution in phi units. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	-4.06
   Maximum:	2.51
   Units:	phi
   Resolution:	0.01

   MEAN

   Average value in the grain size distribution in phi units. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	-2.59
   Maximum:	2.53
   Units:	phi
   Resolution:	0.01

   STDEV

   Standard deviation (root mean square of the deviations) of the grain size distribution in phi units. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.55
   Maximum:	3.45
   Units:	phi
   Resolution:	0.01

   SKEWNESS

   Skewness (deviation from symmetrical form) of the grain size distribution. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	-0.81
   Maximum:	3.54
   Units:	unitless
   Resolution:	0.01

   KURTOSIS

   Kurtosis (degree of curvature near the mode) of the grain size distribution. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	-0.74
   Maximum:	86.57
   Units:	unitless
   Resolution:	0.01

   MODE1CLASS

   First mode (particle size that occurs the most number of times) in phi units. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   MODE1FREQ

   Modal strength of the first mode in percent. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   MODE2CLASS

   Second mode in phi units. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   MODE2FREQ

   Modal strength of the second mode in percent. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   MODE3CLASS

   Third mode in phi units. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   MODE3FREQ

   Modal strength of the third mode in percent. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   NMODES

   Number of modes. This calculation is no longer made in the lab, but attribute value is maintained to be consistent with older datasets. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string. Blank

   PHIM5

   Weight percent of the sample in the -5 phi fraction and coarser (nominal diameter of particles greater than or equal to 32 mm); very coarse pebbles to cobbles. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	0
   Units:	weight percent
   Resolution:	0.01

   PHIM4

   Weight percent of the sample in the -4 phi fraction (nominal diameter of particles greater than or equal to 16 mm, but less than 32 mm); coarse pebbles. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	53.45
   Units:	weight percent
   Resolution:	0.01

   PHIM3

   Weight percent of the sample in the -3 phi fraction (nominal diameter of particles greater than or equal to 8 mm, but less than 16 mm); medium pebbles. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	42.35
   Units:	weight percent
   Resolution:	0.01

   PHIM2

   Weight percent of the sample in the -2 phi fraction (nominal diameter of particles greater than or equal to 4 mm, but less than 8 mm); fine pebbles. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	27.07
   Units:	weight percent
   Resolution:	0.01

   PHIM1

   Weight percent of the sample in the -1 phi fraction (nominal diameter of particles greater than or equal to 2 mm, but less than 4 mm); very fine pebbles (granules). (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	44.61
   Units:	weight percent
   Resolution:	0.01

   PHI_0

   Weight percent of the sample in the 0 phi fraction (nominal diameter of particles greater than or equal to 1 mm, but less than 2 mm); very coarse sand. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.01
   Maximum:	78.76
   Units:	weight percent
   Resolution:	0.01

   PHI_1

   Weight percent of the sample in the 1 phi fraction (nominal diameter of particles greater than or equal to 0.5 mm, but less than 1 mm); coarse sand. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.16
   Maximum:	65.55
   Units:	weight percent
   Resolution:	0.01

   PHI_2

   Weight percent of the sample in the 2 phi fraction (nominal diameter of particles greater than or equal to 0.25 mm, but less than 0.5 mm); medium sand. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	1.67
   Maximum:	80.98
   Units:	weight percent
   Resolution:	0.01

   PHI_3

   Weight percent of the sample in the 3 phi fraction (nominal diameter of particles greater than or equal to 0.125 mm, but less than 0.25 mm); fine sand. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.08
   Maximum:	63.62
   Units:	weight percent
   Resolution:	0.01

   PHI_4

   Weight percent of the sample in the 4 phi fraction (nominal diameter of particles greater than or equal to 0.0625 mm, but less than 0.125 mm); very fine sand. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	18.44
   Units:	weight percent
   Resolution:	0.01

   PHI_5

   Weight percent of the sample in the 5 phi fraction (nominal diameter of particles greater than or equal to 0.031 mm, but less than 0.0625 mm); coarse silt. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	2.35
   Units:	weight percent
   Resolution:	0.01

   PHI_6

   Weight percent of the sample in the 6 phi fraction (nominal diameter of particles greater than or equal to 0.016 mm, but less than 0.031 mm); medium silt. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.01
   Maximum:	3.26
   Units:	weight percent
   Resolution:	0.01

   PHI_7

   Weight percent of the sample in the 7 phi fraction (nominal diameter of particles greater than or equal to 0.00 8mm, but less than 0.016 mm); fine silt. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.01
   Maximum:	4.3
   Units:	weight percent
   Resolution:	0.01

   PHI_8

   Weight percent of the sample in the 8 phi fraction (nominal diameter of particles greater than or equal to 0.004 mm, but less than 0.008 mm); very fine silt. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0.01
   Maximum:	5.27
   Units:	weight percent
   Resolution:	0.01

   PHI_9

   Weight percent of the sample in the 9 phi fraction (nominal diameter of particles greater than or equal to 0.002 mm, but less than 0.004 mm); coarse clay. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	2.71
   Units:	weight percent
   Resolution:	0.01

   PHI_10

   Weight percent of the sample in the 10 phi fraction (nominal diameter of particles greater than or equal to 0.001 mm, but less than 0.002 mm); medium clay. (Source: USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	1.6
   Units:	weight percent
   Resolution:	0.01

   PHI_11

   Weight percent of the sample in the 11 phi fraction and finer (nominal diameter of particles less than 0.001 mm; fine clay. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Range of values
   Minimum:	0
   Maximum:	0.53
   Units:	weight percent
   Resolution:	0.01

   ANALYST

   Person who performed the grain size or physical properties analysis. Typically represented by the person's initials, or first initial last name. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Value	Definition
   MPP	Marcie Purkey Philips
   SAG/AAB	Simone Gibson/Allyson Boggess

   QUALITY_GR

   Truncated from QUALITY GRADE-ANALYST. Quality grades for sample data are assigned based on the calculated percent difference between the weights of the coarse fraction remaining after wet sieving and the sum of all the weighed fractions after dry sieving the coarse fraction, indicating an estimated differing amount of material which could skew the calculated grain size results. A quality grade is assigned as well as the initials of the person that assigned the grading in the format Q-XX where Q is the quality grade and XX are the initials of the person assigning the grade. The values of quality grade reflect all possibilities, not necessarily what occurs in this dataset. (Source: modified from USGS East Coast Sediment Texture Database data dictionary)

   Value	Definition
   Quality grade: A	A = percent differences between 0% and +- 1.5%
   Quality grade: B	B = percent differences between ±1.5% and ±3%
   Quality grade: C	C = percent differences between ±3% and ±4.5%
   Quality grade: D	D = percent differences greater than ±4.5%
   Quality grade analyst: BJB	Brian J. Buczkowski

   LITHOLOGY

   General lithologic description of sample. This field is not always filled in, so will have blanks. (Source: modified from USGS East Coast Sediment Texture Database data dictionary) Character string.

   COMMENTS

   Comments can include information on sample collection, lithology, or amount of shell present. This field is not always used in the lab analysis, but is present in all of these samples and represents the amount of shells -2 phi and larger. (Source: U.S. Geological Survey) Character string.

   Entity_and_Attribute_Overview:

   These attribute definitions describe each column of information in the Excel spreadsheet with the exception of additional information in the last column of the Excel spreadsheet. That column contains an explanation of the quality grading values and how the quality grade is assigned. That column of information is omitted from the CSV and shapefile. The shapefile truncates attribute labels to 10 characters when compared to the Excel spreadsheet and the CSV file. The first row of the spreadsheet is the column heading. The CSV file has the same information and the column definitions are the same - with the last column of the XLSX file omitted (data quality grade explanation). The information in the last column of the XLSX is as follows:
   Data quality grades may be determined by several factors, and any comments or notes that indicate the data for a particular sample may be suspect are included in the results table for that sample under "comments". Quality grades for sample data that do not have any additional comments are assigned based on the calculated percent difference between the weights of the coarse fraction remaining after wet sieving and the sum of all of the weighed fractions after dry sieving the coarse fraction, indicating an estimated differing amount of material which could skew the calculated grain size results.
   A = percent differences between 0% and ±1.5%
   B = percent differences between ±1.5% and ±3%
   C = percent differences between ±3% and ±4.5%
   D = percent differences greater than ±4.5%
   Negative weight percents in phi size distributions and gravel-sand-silt percentages may be the result of a lack of fines present in the actual samples. The statistical spreadsheet used to calculate grain size distribution takes measured weights for the coarse fractions (after wet sieving through a 4 phi sieve) and merges it with the cumulative frequency data obtained from the Multisizer for any fine fraction that remains after wet sieving. These equations include determining the percentage of the sample in fine fraction phi weight percents (5 phi to 11 phi). This fine fraction weight is determined by subtracting the wet sieved portion of the sample from the calculated total weight of the sample (determined after calculating and removing the weight of the water in the sample and weight of salt). If there is any excess mass, no matter how small, determined to be in the coarse fraction weights and not in the corrected weight if the entire sample, the calculations subtract this excess weight from the fines phi distribution to make the sum of the weight percents equal 100%.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Page C. Valentine
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey

   Attn: Page C. Valentine

   Research Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   (508) 548-8700 x2239 (voice)

   (508) 457-2310 (FAX)

   pvalentine@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: 2021 (process 1 of 6)

   Sediment sampling methods:
   As a part of the process of mapping the sea floor, the USGS developed the SEABed Observation and Sampling System (SEABOSS) to collect samples and video and photographic images of the seabed to aid in the interpretation of seabed sonar imagery. A modified Van Veen sediment grab sampler is mounted in the center of the SEABOSS frame, which ensures the sampler is properly oriented on the seabed when a sample is collected. Before deployment, the sampler bucket's jaws are opened by collapsing the extended arms to a near-horizontal position and locking them in place with two catches. The sampler operates passively to sample the seabed; it is not spring loaded.
   To collect a sediment sample, the SEABOSS frame was lowered gently onto the seabed, reducing tension on the cable, which caused the two locking catches to be automatically released by gravity. As the cable was retrieved, the grab sampler's arms were pulled upward, closing the bucket around the sediment, and the SEABOSS was lifted off the seabed.
   The SEABOSS was retrieved and set upon a wooden platform that kept the sampler bucket and camera systems above the deck. The sampler's arms were held in the upright position manually or by tension on the cable, the two doors on the upper side of the bucket were opened, and the sediment surface was photographed before the sediment was removed. For this project, the upper 2 cm of sediment, representing the surface of the seabed, were removed with a rectangular shovel 2-cm deep and stored in a plastic bag for grain-size analysis. The remaining sediment was dumped into a tray on the deck below the sampler and inspected for biological specimens that were collected for use in studies conducted by scientists at the SBNMS and at collaborating academic institutions. Subsequently the sediment was discarded, after which the sampler was washed in preparation for sampling at the next site. Further information on the SEABOSS can be found in Valentine and others (2000). The samples were collected over a time period from 2020 to 2021 with the process date representing the most recent data collection. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Page C. Valentine

   Research Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   (508) 548-8700 x2239 (voice)

   (508) 457-2310 (FAX)

   pvalentine@usgs.gov

   Date: 2022 (process 2 of 6)

   Samples were analyzed in the sediment laboratory at the USGS Woods Hole Coastal and Marine Science Center. Samples submitted to the sediment analysis laboratory for grain size analysis using the Beckman Coulter Multisizer3 and sieving of the ≥ 4 phi fraction are assigned unique analysis identifiers (ANALYSIS_ID), and a macro-enabled Microsoft Excel data entry spreadsheet (GrainSizeWorksheet_xxxx.xlsm, where xxxx is the batch number assigned to the sample submission) is created to record the measurement data. About 50 grams of wet sediment are placed in a pre-weighed beaker, weighed, oven dried at 100 degrees Celsius (degC), and reweighed to correct for salt. The dried sample is wet sieved through a 0.062 mm (No. 230) sieve. The coarse fraction remaining in the sieve is oven dried at 100 degC (until completely dried) and weighed. The fine fraction in water is collected in a plastic Nalgene bottle and sealed with a screw lid (stored for no longer than one week). The coarse fraction is dry sieved to determine the individual weights of the 4 to -5 phi fractions, and the weights are recorded in the data entry spreadsheet. At the request of the submitter, shell and shell fragments can be manually removed from the -2 phi and coarser fractions, weighed and their weights are recorded in the data entry spreadsheet. The fine fraction is run and combined using the 200 μm and 30 μm Coulter analyses using the Multisizer3 software to get the fine fraction grain size distribution. The fine fraction distribution data are added to the data entry spreadsheet. The spreadsheet is used to calculate a continuous phi class distribution from the original fractions. For these data, those analysis dates ranged from 2021 to 2022.
   The process date refers to the latest processing date. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Brian J. Buczkowski

   Physical Scientist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   (508) 548-8700 x2361 (voice)

   (508) 457-2310 (FAX)

   bbuczkowski@usgs.gov

   Date: 2022 (process 3 of 6)

   Continuous phi class distribution from the original fractions are transposed to the "results" tab in the macro-enabled Microsoft Excel data entry workbook (GrainSizeWorksheet_xxxx.xlsm, where xxxx is the identifier assigned to the sample submission). Macros in the workbook ("GS_statistics" and "sedimentname") are run to calculate grain size classification and statistical analyses and finish processing the data. Sample, navigation, and field identifiers, along with continuous phi class distribution data, grain size classification, and statistical analysis results are copied and pasted into a final Microsoft Excel spreadsheet (xxxx_GS-MS_results.xlsx, where xxxx is the batch number assigned to the sample submission). The processed data are quality control checked and assigned a quality grade based on the examination of the analytical data. Processed data are released to the submitter and incorporated into the laboratory's database. All raw analytical data generated by the samples are archived in the sediment analysis laboratory. For these data, those analysis dates ranged from 2021 to 2022.
   The process date refers to the latest processing date. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Brian J. Buczkowski

   Physical Scientist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   (508) 548-8700 x2361 (voice)

   (508) 457-2310 (FAX)

   bbuczkowski@usgs.gov

   Date: 2022 (process 4 of 6)

   The three separate field activities were combined into a single spreadsheet using Excel 365. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

   Date: 2022 (process 5 of 6)

   The Excel spreadsheet was exported as a CSV UTF-8 file using Excel 365, omitting the last column of information (QUALITY GRADING GUIDELINES) which is not individual station information.

   Date: 2022 (process 6 of 6)

   Using Esri ArcGIS 10.8.1, the CSV file was converted to a shapefile within Esri ArcMap using File - Add Data - Add XY data. The CSV file was selected, with the x-coordinate set to LONGITUDE and the y-coordinate set to LATITUDE. The coordinate system of the input coordinates was set to the geographic coordinate system GCS_WGS_1984. Once the event theme was added to ArcMap, the data were then converted to a shapefile by right-clicking on the event theme - Data - Export Data. All the features were exported using the layer's source data for the coordinate system. The output shapefile was set to stellwagen_2020_2021_sedsamps.shp.

3. What similar or related data should the user be aware of?
   Blackwood, D.S., and Parolski, K.F., 2001, Seabed observation and sampling system: Sea Technology v. 42, no. 2, p.39-43.

   Valentine, P., Blackwood, D., and Parolski, K., 2000, Seabed Observation and Sampling System: U.S. Geological Survey Fact Sheet FS-142-00, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/fs14200
   • https://pubs.usgs.gov/fs/fs142-00/

   Poppe, L.J., McMullen, K.Y., Williams, S.J., and Paskevich, V.F., 2014, USGS East-Coast Sediment Analysis: Procedures, Database, and GIS Data: Open-File Report 2005-1001, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/ofr20051001
   • https://pubs.usgs.gov/of/2005/1001/

   Valentine, P.C., and Cross, V.A., 2019, Location and analyses of sediment samples collected on Stellwagen Bank off Boston, Massachusetts from November 5, 2013 to April 30, 2019 on U.S. Geological Survey field activities: data release DOI:10.5066/P9FWFLPD, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9FWFLPD
   • https://www.sciencebase.gov/catalog/item/5d95153ee4b0c4f70d10a4f7

   Other_Citation_Details:

   This publication includes the grain-size analyses of the sediment samples collected on 20 other field activities.

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?
   The location information for stations was acquired from a satellite navigation receiver (Furuno Satellite Compass SC-30, GPS receiver) in geographic coordinates (World Geodetic System of 1984 [WGS 84]) with a horizontal accuracy of 10 m. Cruise 2020-012-FA acquired navigation at two-second intervals on September 24 and five-second intervals on September 25. Cruise 2021-016-FA acquired navigation at a two-second interval. Cruise 2021-017-FA acquired navigation at a two-second interval. The navigation antenna was located 5.3 m forward of the SEABOSS deployment location. This offset was not accounted for in the navigation acquisition, so navigation fixes represent the antenna location. The SEABOSS may also drift away from the survey vessel when deployed to the sea floor.
3. How accurate are the heights or depths?
   Water depth relative to the local sea surface was determined using a Simrad ES60, 120 kHz, single beam echosounder using a dual frequency 120-25 kHz transducer, which detects the seabed to a depth of 800 m. Depth values were rounded to the nearest meter to account for ship motion. The water depths were transcribed manually, so some errors could be associated with that process. The depth is relative to the transducer location, no adjustment was made for tides or transducer depth.
4. Where are the gaps in the data? What is missing?
   These data represent all the sediment samples collected as part of the three field activities that occurred from September 2020 to August 2021. However, a sample was not acquired at every station visited during the survey. Samples were discarded at sea if the sediment composition was visibly altered during collection, for example, if the sampler did not close properly causing sediment to be lost during recovery of the sample. A total of 137 sediment samples were collected and analyzed for grain size composition from the associated field activities.
   2020-012-FA: Sediment samples were successfully collected at 29 of the 33 stations visited.
   2021-016-FA: Sediment samples were successfully collected at 37 of the 43 stations visited.
   2021-017-FA: Sediment samples were successfully collected at 72 of the 93 stations visited. However, one sample (5081) was destroyed in the lab during grain-size analysis resulting in grain-size results for a total of 71 sediment samples.
5. How consistent are the relationships among the observations, including topology?
   This dataset is based on the original sediment analyses files returned to the scientist after processing at the Woods Hole Coastal and Marine Science Center sediment lab. Over the years, some of the columns of information have varied, but not the sediment analyses columns. All of the field activities used the same research vessel, the R/V Auk. For the most part, the values of the attribute field titled FIELD_NO are in a sequential order (minus stations where samples were not acquired).
   Negative weight percents (if present) in phi size distributions and gravel-sand-silt percentages may be the result of a lack of fines present in the actual samples. The statistical spreadsheet used to calculate grain size distribution takes measured weights for the coarse fractions (after wet sieving through a 4 phi sieve) and merges it with the cumulative frequency data obtained from the Multisizer for any fine fraction that remains after wet sieving. These equations include determining the percentage of the sample in fine fraction phi weight percents (5 phi to 11 phi). This fine fraction weight is determined by subtracting the wet sieved portion of the sample from the calculated total weight of the sample (determined after calculating and removing the weight of the water in the sample and weight of salt). If there is any excess mass, no matter how small, determined to be in the coarse fraction weights and not in the corrected weight if the entire sample, the calculations subtract this excess weight from the fines phi distribution to make the sum of the weight percents equal 100%.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - ScienceBase

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   USA

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? The dataset contains the sediment sample analysis data in three formats - an Excel file (stellwagen_2020_2021_sedsamps.xlsx), a CSV file (stellwagen_2020_2021_sedsamps.csv), and a shapefile (stellwagen_2020_2021_sedsamps.shp and additional files that make up a shapefile). In addition to the sediment analysis files, the dataset contains the browse graphic (stellwagen_2020_2021_sedsamps_browse.jpg) and FGDC CSDGM metadata in XML format.
3. What legal disclaimers am I supposed to read?
   Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.
4. How can I download or order the data?
   • Availability in digital form:

     Data format:	The dataset contains the sediment sample analysis in XLSX, CSV and shapefile formats, along with the FGDC CSDGM metadata. in format XLSX (version Microsoft Excel 365) Size: 1
     Network links:	https://www.sciencebase.gov/catalog/file/get/633c99a1d34e900e86cf1ab7 https://www.sciencebase.gov/catalog/item/633c99a1d34e900e86cf1ab7 https://doi.org/10.5066/P9G7QARQ

     Data format:	The dataset contains the sediment sample analysis in XLSX, CSV and shapefile formats, along with the FGDC CSDGM metadata. in format CSV (version exported from Microsoft Excel 365) Size: 1
     Network links:	https://www.sciencebase.gov/catalog/file/get/633c99a1d34e900e86cf1ab7 https://www.sciencebase.gov/catalog/item/633c99a1d34e900e86cf1ab7 https://doi.org/10.5066/P9G7QARQ

     Data format:	The dataset contains the sediment sample analysis in XLSX, CSV and shapefile formats, along with the FGDC CSDGM metadata. in format Shapefile (version Esri ArcGIS 10.8.1) Size: 1
     Network links:	https://www.sciencebase.gov/catalog/file/get/633c99a1d34e900e86cf1ab7 https://www.sciencebase.gov/catalog/item/633c99a1d34e900e86cf1ab7 https://doi.org/10.5066/P9G7QARQ

     Data format:	Web mapping service of the dataset. in format WMS (version 1.3.0)
     Network links:	https://www.sciencebase.gov/catalogMaps/mapping/ows/633c99a1d34e900e86cf1ab7?service=wms&request=getcapabilities&version=1.3.0 https://www.sciencebase.gov/catalog/item/633c99a1d34e900e86cf1ab7 https://doi.org/10.5066/P9G7QARQ

     Data format:	Web feature service of the dataset. in format WFS (version 1.0.0)
     Network links:	https://www.sciencebase.gov/catalogMaps/mapping/ows/633c99a1d34e900e86cf1ab7?service=wms&request=getcapabilities&version=1.3.0 https://www.sciencebase.gov/catalog/item/633c99a1d34e900e86cf1ab7 https://doi.org/10.5066/P9G7QARQ

   • Cost to order the data: none

5. What hardware or software do I need in order to use the data set?
   The dataset contains data in XLSX, CSV, and Esri shapefile formats. The user must have software capable of uncompressing the zip file as a result of downloading the full dataset. Additionally, the user must have software capable of reading the data formats.

Who wrote the metadata?

Dates:

Last modified: 21-Mar-2023

Metadata author:

U.S. Geological Survey

Attn: VeeAnn A. Cross

Marine Geologist

384 Woods Hole Rd.

Woods Hole, MA

508-548-8700 x2251 (voice)

508-457-2310 (FAX)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with the USGS.

Metadata standard:

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