Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes on the South Shore of Cape Cod, Massachusetts, From 2013 Through 2014

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes on the South Shore of Cape Cod, Massachusetts, From 2013 Through 2014
Abstract:
The accretion history of fringing microtidal salt marshes located on the south shore of Cape Cod, Massachusetts, was reconstructed from sediment cores collected in low and high marsh vegetation zones. The location of these marshes within protected embayments and the absence of large rivers on Cape Cod result in minimal sediment supply and a dominance of organic matter contribution to sediment peat. Age models based on 210-lead and 137-cesium were constructed to evaluate how vertical accretion and carbon burial rates have changed over the past century. The continuous rate of supply age model was used to age date 11 cores (10 low marsh and 1 high marsh) across four salt marshes. Both vertical accretion rates and carbon burial increased from 1900 to the years of collection, 2013 and 2014. Elevation of the marsh surface was measured to evaluate where the marsh falls within the current tidal frame. The historic marsh surface elevation was then reconstructed from the calculated age of each depth interval and its elevation, assuming that elevations within this shallow zone (less than 30 centimeters) have been preserved for the past century.
  1. How might this data set be cited?
    Gonneea, Meagan Eagle, Jennifer A. O'Keefe Suttles, and Kroeger, Kevin D., 2018, Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes on the South Shore of Cape Cod, Massachusetts, From 2013 Through 2014: U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Gonneea, M.E., O'Keefe Suttles, J.A., and Kroeger, K.D., 2018, Collection, analysis, and age-dating of sediment cores from salt marshes on the south shore of Cape Cod, Massachusetts, from 2013 through 2014: U.S. Geological Survey data release, https://doi.org/10.5066/F7H41QPP.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.556945801557
    East_Bounding_Coordinate: -70.496520996872
    North_Bounding_Coordinate: 41.584306748081
    South_Bounding_Coordinate: 41.543205912373
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5a748e35e4b00f54eb19f96c/?name=Saltmarsh_AR.jpg (JPEG)
    Browse graphic showing a plot of the accretion rates at each of the core locations.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 04-Dec-2013
    Currentness_Reference:
    Ground Condition. These are the dates when the cores were collected.
  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 (549)
    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 1.0E-5. Longitudes are given to the nearest 1.0E-5. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: NAVD88
      Depth_Resolution: 1.0
      Depth_Distance_Units: centimeters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    South Shore Cape Cod Salt Marsh Core Data
    Core location, elevation, radiochemistry results, age model, and carbon and nitrogen results (Source: Meagan E. Gonneea)
    Core ID
    ID: Each core is assigned an alphabetical ID to indicate which marsh it was collected at (defined below) and a secondary qualifier of A, B or C, indicating the order of core collection over time. (Source: Producer defined.)
    ValueDefinition
    SLPSage Lot Pond
    EPEel Pond
    HBHamblin Pond
    GPGreat Pond
    Collection Date
    Date: A numeric identifier of the date the core was collected in the format of month/day/year. (Source: Producer defined.)
    Range of values
    Minimum:12/4/2013
    Maximum:8/5/2014
    Latitude
    Lat: Latitude decimal degrees north, NAD83. (Source: Producer defined.)
    Range of values
    Minimum:41.55445
    Maximum:41.47671
    Longitude
    Lon: Longitude decimal degrees west, NAD83. (Source: USGS)
    Range of values
    Minimum:70.50044
    Maximum:70.58044
    Depth from sediment surface, interval mean (cm)
    Depth: A numeric identifier of the interval mid-point depth below the sediment interface in centimeters. (Source: Producer defined.)
    Range of values
    Minimum:0
    Maximum:159
    Elevation relative to NAVD88, interval mean (cm)
    Elevation: A numeric identifier of interval mid-point elevation relative to NAVD88 datum in centimeters. Calculated by subtracting the mid-interval depth from the NAVD88 elevation of the core location (depth = 0). (Source: Producer defined.)
    Range of values
    Minimum:-144
    Maximum:24
    Dry bulk density (g/cm3)
    DBD: A numeric identifier of the sediment dry bulk density in grams per cubic centimeter (g/cm3). Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.02
    Maximum:1.87
    210-Lead total (dpm/g)
    210Pb: A numeric identifier of the sediment total 210-lead activity in decays per minute per gram (dpm/g). Measured at 46.6 kiloelectronvolt (KeV) on a planar gamma counter. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.21
    Maximum:36.94
    210-Lead total error (dpm/g)
    210Pb_e: A numeric identifier of the measurement error in sediment total 210-lead activity in decays per minute per gram (dpm/g). Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.06
    Maximum:3.73
    226-Radium (dpm/g)
    226Ra: A numeric identifier of the sediment total 226-radium activity in decays per minute per gram (dpm/g). Measured at 352 kiloelectronvolt (KeV) on a planar gamma counter. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.14
    Maximum:3.32
    226-Radium error
    226Ra_e: A numeric identifier of the measurement error in sediment total 226-radium activity in decays per minute per gram (dpm/g). Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.01
    Maximum:0.79
    210-Lead excess (dpm/g)
    210Pbex: A numeric identifier of the sediment excess 210-Lead activity in decays per minute per gram (dpm/g). Calculated as the difference between total 210-Lead and total 226-Radium activities. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:-0.13
    Maximum:36.30
    210-Lead excess error (dpm/g)
    210Pbex_e: A numeric identifier of the propagated measurement error in sediment excess 210-Lead activity in decays per minute per gram (dpm/g). Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.07
    Maximum:3.81
    137-Cesium (dpm/g)
    137Cs: A numeric identifier of the sediment total 137-Cesium activity in decays per minute per gram (dpm/g). Measured at 662 kiloelectronvolt (KeV) on a planar gamma counter. Values of -99999 indicate this measurement was not performed, zero values are below detection limit. (Source: Producer defined.)
    Range of values
    Minimum:0.00
    Maximum:2.96
    137-Cesium error (dpm/g)
    137Cs_e: A numeric identifier of the measurement error in sediment total 137-Cesium activity in decays per minute per gram (dpm/g). Values of -99999 indicate this measurement was not performed, zero values are below detection limit. (Source: Producer defined.)
    Range of values
    Minimum:0.00
    Maximum:0.33
    7-Beryllium (dpm/g)
    7Be: A numeric identifier of the measurement error in sediment total 7-Beryllium activity in decays per minute per gram (dpm/g). Measured at 447 kiloelectronvolt (KeV) on a planar gamma counter. Values of -99999 indicate this measurement was not performed, zero value are below detection limit. (Source: Producer defined.)
    Range of values
    Minimum:0.00
    Maximum:12.54
    7-Beryllium error (dpm/g)
    7Be_e: A numeric identifier of the measurement error in sediment total 7-Beryllium activity in decays per minute per gram (dpm/g). Values of -99999 indicate this measurement was not performed, zero values are below detection limit. (Source: Producer defined.)
    Range of values
    Minimum:0.00
    Maximum:2.00
    Weight percent carbon
    wtC: Total amount of carbon by weight percent in soil as measured with an Elementar Vario EL Cube or Micro Cube elemental analyzer at University of California at Davis Stable Isotope Facility. This value was measured on combined consecutive samples, for example 0 to 1 cm and 1 to 2 cm, were combined for a sample from 0 to 2 cm. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.4
    Maximum:42.5
    Weight percent nitrogen
    wtN: Total amount of nitrogen by weight percent in soil as measured with an Elementar Vario EL Cube or Micro Cube elemental analyzer at University of California at Davis Stable Isotope Facility. This value was measured on combined consecutive samples, for example 0 to 1 cm and 1 to 2 cm, were combined for a sample from 0 to 2 cm. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.02
    Maximum:2.66
    Carbon 13/12 ratio
    13C: The carbon isotopic signature of the soil sample relative to Pee Dee Belemnite (PDB) standard as measured with an Elementar Vario EL Cube or Micro Cube elemental analyzer interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer at University of California at Davis Stable Isotope Facility. This value was measured on combined consecutive samples, for example 0 to 1 cm and 1 to 2 cm, were combined for a sample from 0 to 2 cm. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:-27.75
    Maximum:-12.54
    Nitrogen 15/14 ratio
    15N: The nitrogen isotopic signature of the soil sample relative to air as measured with an Elementar Vario EL Cube or Micro Cube elemental analyzer interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer at University of California at Davis Stable Isotope Facility. This value was measured on combined consecutive samples, for example 0 to 1 cm and 1 to 2 cm, were combined for a sample from 0 to 2 cm. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:-0.82
    Maximum:5.33
    Sediment age (years)
    Age: A numeric identifier for the age in years from the collection date of the core interval based on the Continuous Rate of Supply 210-Lead age model. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:1.1
    Maximum:103.8
    Sediment Age Error (years)
    Age_e: A numeric identifier for the age model uncertainty in years of the core interval based on the Continuous Rate of Supply 210-Lead age model. Error is propagated through the model. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:0.1
    Maximum:18.2
    Vertical Accretion Rate (mm/y)
    VAR: A numeric identifier for the vertical accretion rate of the sediment in millimeters per year (mm/y). Calculated as the difference in interval midpoint divided by the difference in ages of those adjacent sediment intervals. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:1.0
    Maximum:9.7
    Mass Accumulation Rate (g/m2/y)
    MAR: A numeric identifier for the mass accumulation rate of the sediment in grams per square meter per year (g/m2/y). Calculated by multiplying dry bulk density times vertical accretion rate. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:104
    Maximum:1285
    Carbon accumulation rate (gC/m2/y)
    CAR: A numeric identifier for the carbon mass accumulation rate of the sediment in grams of carbon per square meter per year (gC/m2/y). Calculated by multiplying the average mass accumulations rate for the combined depth interval of the elemental sample times weight percent carbon. Values of -99999 indicate this measurement was not performed. (Source: Producer defined.)
    Range of values
    Minimum:19
    Maximum:380
    Entity_and_Attribute_Overview:
    Any value below detection is given the numerical value of 0, with the exception of surface elevation, which is 0. Any attribute that wasn't measured for a specific sample is listed as -99999. The data are available in both XLSX and CSV formats. The attribute label in the detailed description above is the first row of the Excel spreadsheet. The first part of the attribute definition (before the colon) indicates the abbreviated label for that column and is on the second row of the Excel spreadsheet. The abbreviated column heading is provided as a convenience for using the data in other software packages that might have difficulty with the longer label.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey - Meagan E. Gonneea

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Meagan Eagle Gonneea
    • Jennifer A. O'Keefe Suttles
    • Kevin D. Kroeger
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Meagan Eagle Gonneea
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-457-2280 (voice)
    mgonneea@usgs.gov

Why was the data set created?

These cores were collected, age dated, and their elevation measured to determine what elevation trajectories salt marsh surfaces have followed over the past century as sea level has risen at a rate of 2.8 mm/yr. In addition, carbon burial was evaluated to determine what rates were over the past century.

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: 05-Aug-2014 (process 1 of 5)
    Eleven sediment cores were collected in coastal salt marshes between 12/4/2013 and 8/5/2014. All cores were collected in the low marsh except SLPB, which was collected in the high marsh. A piston coring system was used, where the core liner (diameter 11 cm, 1-2 m in length) was fitted with a gasketed piston that was placed on the sediment surface. The clear, sharpened core liner was pushed down into the marsh subsurface, while the piston was maintained at the marsh surface via tension on the piston. We visually observed the sediment surface to ensure that the soil column did not compact during collection. Once the core reached the underlying coarse sediment interface (except at Hamblin Pond, where the depth to the peat base was >2 m), the core liner and piston were removed from the marsh with a pulley system. The process date reflects the last occurrence of the work. This process step and all subsequent steps were performed by the same people, Meagan E. Gonneea and Jennifer O'Keefe Suttles, unless otherwise noted. Person who carried out this activity:
    Meagan E Gonneea
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    United States

    508-457-2280 (voice)
    mgonneea@usgs.gov
    Date: 2016 (process 2 of 5)
    After each core collection, the sediment cores were immediately returned to the Woods Hole Coastal and Marine Science Center. They were placed in a refrigerator for 1 to 3 days, then split vertically, sectioned at 1 or 2 cm intervals, frozen, and then freeze dried for 7 days, until sediment weights did not change further. Dry bulk density was determined as the dry weight of a known volume of sample. Approximately 5 g of dried sediment sample was blended and homogenized prior to sealing in a jar for a minimum of three weeks and then placed on a planar-type gamma counter for 24 to 48 hours to measure 7Be, 137Cs, 210Pb, and 226Ra at 477, 661.6, 46.5 and 352 kiloelectronvolts (KeV) energies respectively (Canberra Inc., USA). Detector efficiency was determined from EPA standard pitchblende ore in the same geometry as the samples. Activities of 7Be, 137Cs, and 210Pb were decay corrected to time of collection. Suppression of low energy peaks by self-absorption was corrected for according to Cutshall and others, 1983. Detection limit for excess 210Pb was 0.05 dpm/g (disintegrations per minute per gram). Sediment ages and accretion rates were calculated with the continuous rate of supply 210Pb age model, a variant on the advection-decay equation (Appleby and Oldfield, 1978; Goldberg, 1963). This model assumes that 210Pb supply to the sediment surface is constant through time, but allows for changing sedimentation rates, in addition to decay, to control the down-core activity of 210Pb. The common form of the CRS (constant rate of 210Pb supply) model as derived by Appleby and Oldfield (1978) solves for age based on the distribution of 210Pb in the sediment record. Prior to application of the age model, 210Pb profiles were evaluated to ensure they were sufficiently resolved to apply the CRS model without bias towards to ages that are too old or accretion rates that are too low at depth (Binford, 1990). All gamma analyses were ongoing from 2014 and completed in 2016.
    Appleby, P.G., and Oldfield, Frank, 1978, The calculation of lead-210 dates assuming a constant rate of supply of unsupported 210Pb to the sediment: Catena, v. 5, issue 1, p. 1–8, https://doi.org/10.1016/S0341-8162(78)80002-2.
    Binford, M.W., 1990, Calculation and uncertainty analysis of 210 Pb dates for PIRLA project lake sediment cores: Journal of Paleolimnology, v. 3, issue 3, p. 253-267, https://doi.org/10.1007/BF00219461.
    Cutshall, N.H., Larsen, I.L., and Olsen, C.R., 1983, Direct analysis of 210 Pb in sediment samples—Self-absorption corrections: Nuclear Instruments and Methods in Physics Research, v. 206, issues 1–2 , p. 309–312, https://doi.org/10.1016/0167-5087(83)91273-5.
    Goldberg, E.D, 1963, Geochronology with 210 Pb, in Miller, J.A., convener, Radioactive dating: International Atomic Energy Agency Symposium on Radioactive Dating, Athens, Greece, November 19-23, 1962, [Proceedings], p. 121-131. Person who carried out this activity:
    Meagan E Gonneea
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    United States

    508-457-2280 (voice)
    508-457-2310 (FAX)
    mgonneea@usgs.gov
    Date: 2015 (process 3 of 5)
    A subsample of freeze dried sediment was combined from two consecutive depths (for example, 0 to 1 and 1 to 2) to represent the mixed interval for elemental analysis. For this sample, 0.5 g of the sediment was ball-milled to a fine powder and packaged for carbon and nitrogen analysis at the U.C. Davis Stable Isotope Facility. There carbon and nitrogen content and isotopic ratio of the sediment organic matter was measured with an Elementar Vario EL Cube or Micro Cube elemental analyzer interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer. Carbon isotopic ratios are reported relative to Pee Dee Belemnite (PDB) and nitrogen isotopic ratios relative to air. These analyses occurred concurrently with analyses in the previous process step. Person who carried out this activity:
    Meagan E Gonneea
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    United States

    508-457-2280 (voice)
    mgonneea@usgs.gov
    Date: 2014 (process 4 of 5)
    The marsh surface elevation at the core collection sites were surveyed with a Trimble Real-Time Kinematic Geographic Positioning System (RTK GPS) shortly after collection. All data were projected in NAD 1983 Massachusetts State Plane FIPS 2001 and elevations are given relative to NAVD88. The elevation accuracy is 2-3 cm relative to NAVD88. This process step took place over time, with the last measurement in 2014. Person who carried out this activity:
    Meagan E Gonneea
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    United States

    508-457-2280 (voice)
    mgonneea@usgs.gov
    Date: 2018 (process 5 of 5)
    The Excel spreadsheet was exported as a CSV file from Excel for Mac version 15.33. Person who carried out this activity:
    Meagan E Gonneea
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA
    United States

    508-457-2280 (voice)
    mgonneea@usgs.gov
  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?
    Radionuclides (210Pb, 226Ra, 137Cs, 7Be) were measured on planar gamma counters that were standardized to an EPA standard pitchblende ore in the same geometry as the samples. Suppression of low energy peaks by self-adsorption was corrected according to Cutshall and others (1983). Weight percent carbon and nitrogen and the isotopic signature of carbon and nitrogen in organic matter was analyzed at the U.C. Davis Stable Isotope Facility with an Elementar Vario EL CUbe or MIcro Cube elemental analyzer interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer. Long-term standard deviation is 0.2 permil for 13C and 0.3 per mil for 15N.
  2. How accurate are the geographic locations?
    Latitude and Longitude was measured with a handheld Garmin 76Cx GPSmap unit in the field at time of collection. The GPS unit indicated accuracy was within 3 meters. No formal positional accuracy tests were conducted.
  3. How accurate are the heights or depths?
    Elevation was measured with a Trimble Real-Time Kinematic (RTK) GPS after core collection. Accuracy was 2-3 cm according to instrument corrections. No formal positional accuracy tests were conducted.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. All sample measurements are reported.
  5. How consistent are the relationships among the observations, including topology?
    Any value below detection is given the numerical value of 0. Any attribute that wasn't measured for a specific sample is listed as -99999. Each sample was treated in the same manner for each analysis.

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: none
  1. Who distributes the data set? (Distributor 1 of 1)
    ScienceBase
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    United States

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? This data release contains the core location, elevation, radiochemistry results, age model, and carbon and nitrogen results in an Excel spreadsheet (Waquoit_Core_data_release.xlsx), CSV file (Waquoit_Core_data_release.csv) and browse graphic (Saltmarsh_AR.jpg). FGDC CSDGM metadata (Waquoit_Core_data_release_meta.xml) accompanies the data.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 12-Feb-2018
Metadata author:
Meagan E Gonneea
U.S. Geological Survey
384 Woods Hole Rd.
Woods Hole, MA
USA

508-457-2280 (voice)
mgonneea@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/data_release/DR_F7H41QPP/Waquoit_Core_data_release_meta.faq.html>
Generated by mp version 2.9.49 on Mon Sep 10 17:44:57 2018