Eddy covariance fluxes of carbon dioxide and methane from the Herring River in Wellfleet, MA (ver 2.0, June 2022)

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Frequently anticipated questions:

What does this data set describe?

Title:
Eddy covariance fluxes of carbon dioxide and methane from the Herring River in Wellfleet, MA (ver 2.0, June 2022)
Abstract:
Saline tidal wetlands are important sites of carbon sequestration and produce negligible methane (CH4) emissions due to regular inundation with sulfate-rich seawater. Yet, widespread management of coastal hydrology has restricted vast areas of coastal wetlands to tidal exchange. These ecosystems often undergo impoundment and freshening, which in turn cause vegetation shifts like invasion by Phragmites, that affect ecosystem carbon balance. Understanding controls of carbon exchange in these understudied ecosystems is critical for informing climate consequences of blue carbon restoration and/or management interventions. Here we present measurements of net ecosystem exchange of carbon dioxide (CO2) and methane, along with ancillary meteorological data, collected from coastal wetlands across Cape Cod to evaluate the effect of hydrological management and salinity on carbon exchange in coastal wetlands.
Supplemental_Information:
See the following field activities for additional information: https://cmgds.marine.usgs.gov/fan_info.php?fan=2020-019-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-026-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-011-FA
Continuous data on water table height, salinity, and water temperature at the eddy covariance site included here is available in O'Keefe Suttles and others, 2022 and continuous soil and air temperature at this site is included in this data release in air_soil_temp.csv (for May 2020-May 2021) and air_soil_temp_2021-2022.csv (for May 2021-May 2022).
O'Keefe Suttles, J.A., Eagle, M.J., Sanders-DeMott, R., Nick, S.K., Brooks, T.W., Mann, A.G., and Kroeger, K.D., 2022, Continuous water level, salinity, and temperature data from coastal wetland monitoring wells, Cape Cod, Massachusetts: U.S. Geological Survey data release, https://doi.org/10.5066/P9T1KOTW.
  1. How might this data set be cited?
    Sanders-DeMott, Rebecca, Eagle, Meagan, Kroeger, Kevin, Wang, Faming, Brooks, T. Wallace, Jennifer A. O'Keefe Suttles, Nick, Sydney, Mann, Adrian, and Tang, Jianwu, 20220427, Eddy covariance fluxes of carbon dioxide and methane from the Herring River in Wellfleet, MA (ver 2.0, June 2022): data release DOI:10.5066/P9RRL3T0, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Sanders-DeMott, Rebecca, Eagle, Meagan, Kroeger, Kevin, Wang, Faming, Brooks, T. Wallace, Jennifer A. O'Keefe Suttles, Nick, Sydney, Mann, Adrian, and Tang, Jianwu, 2022, Carbon dioxide and methane fluxes with supporting environmental data from coastal wetlands across Cape Cod, Massachusetts (ver 2.0, June 2022): data release DOI:10.5066/P9RRL3T0, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Sanders-DeMott, R., Eagle, M.J., Kroeger, K.D., Wang, F., Brooks, T.W., O'Keefe Suttles, J.A., Nick, S.K., Mann, A.G., and Tang, J., 2022, Carbon dioxide and methane fluxes with supporting environmental data from coastal wetlands across Cape Cod, Massachusetts (ver 2.0, June 2022): U.S. Geological Survey data release, https://doi.org/10.5066/P9RRL3T0.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.0555000
    East_Bounding_Coordinate: -70.0550000
    North_Bounding_Coordinate: 41.9380000
    South_Bounding_Coordinate: 41.9375000
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/625880b7d34e21f82770a19b?name=phramites_eddycovariance.jpg (JPEG)
    Browse graphic is a photograph of a Phragmites wetland in the Herring River estuary in Wellfleet, MA.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 21-May-2020
    Ending_Date: 19-May-2022
    Currentness_Reference:
    Ground condition. These dates bracket the period of monthly sampling when the measurements were made.
  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?
      Indirect_Spatial_Reference:
      Geographic Names Information System (GNIS) placenames are included as keywords to give the general location of core collections. The entity contains attributes with specific latitude and longitude of each core collection; several attributes are also included to describe the core collection location (nearest body of water and vegetation type). Refer to the entity and attribute definitions for "site_name", "status", and "veg_type" for details.
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (34876)
    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:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    phragmites_eddycovariance.csv
    Comma Separated Value (CSV) file containing half hourly data on flux of CO2, CH4, and associated meteorological parameters. (Source: Producer Defined)
    datetime
    Date and time that sensor measurement was logged in local standard time (UTC - 05:00) in the format yyyy-mm-dd hh:mm:ss. (Source: Producer Defined) Numeric value representing the date and time.
    site_name
    Site of the sampling location (Source: Producer Defined)
    ValueDefinition
    Herring RiverA site located within the Cape Cod National Seashore in Wellfleet, MA.
    status
    Hydrological management status of the sampling location (Source: Producer Defined)
    ValueDefinition
    ImpoundedIndicates that at this sampling location water is retained but tidal exchange is limited or excluded by infrastructure such as dikes, roads, or culverts.
    veg_type
    Dominant vegetation at sampling location (Source: Producer Defined)
    ValueDefinition
    Phragmites WetlandSampling location is a wetland dominated by Phragmites australis
    latitude
    Latitude decimal degrees north, NAD83 (Source: Producer Defined)
    Range of values
    Minimum:41.93804
    Maximum:41.93804
    Units:decimal degrees
    longitude
    Longitude decimal degrees west, NAD83. The negative value indicates a location in the western hemisphere. (Source: Producer Defined)
    Range of values
    Minimum:-70.0553
    Maximum:-70.0553
    Units:decimal degrees
    elevation
    Elevation relative to NAVD88 datum in meters. (Source: Producer Defined)
    Range of values
    Minimum:0.33
    Maximum:0.33
    Units:meters
    NEE
    Net ecosystem exchange of carbon dioxide (also referred to as carbon dioxide flux) in micromoles of CO2 per square meter per second (umol CO2 m-2 sec-1). Positive values indicate a flux of CO2 out of the ecosystem into the atmosphere and negative values indicate a flux out of the atmosphere into the ecosystem. (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction or poor quality measurement according to quality flag as defined in process step
    Range of values
    Minimum:-67.5839
    Maximum:74.5949
    Units:umol CO2 m-2 sec-1
    qc_NEE_flux
    Quality control flag for calculated net ecosystem exchange (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction
    0best quality calculated flux
    1fluxes suitable for general analysis such as annual budgets
    2fluxes that should be discarded from the results dataset
    3fluxes that should be discarded from dataset due to known maintenance, instrument malfunction, or rain event
    CH4_flux
    Ecosystem flux of methane in nanomoles of CH4 per square meter per second (nmol CH4 m-2 sec-1). Positive values indicate a flux of methane out of the ecosystem into the atmosphere and negative values indicate a flux out of the atmosphere into the ecosystem. (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction or poor quality measurement according to quality flag as defined in process step
    Range of values
    Minimum:-0.3043
    Maximum:0.4714
    Units:nmol CH4 m-2 sec-1
    qc_CH4_flux
    Quality control flag for calculated methane flux. (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction
    0best quality calculated flux
    1fluxes suitable for general analysis such as annual budgets
    2fluxes that should be discarded from the results dataset
    3fluxes that should be discarded from dataset due to known maintenance, instrument malfunction, or rain event
    LE
    Latent heat exchange between the surface and the atmosphere in Watts per meter squared (W m-2) (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction or poor quality measurement according to quality flag as defined in process step
    Range of values
    Minimum:-188.260
    Maximum:460.703
    Units:W m-2
    qc_LE
    Quality control flag for calculated latent heat exchange between the surface and the atmosphere (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction
    0best quality calculated flux
    1fluxes suitable for general analysis such as annual budgets
    2fluxes that should be discarded from the results dataset
    3producer defined fluxes that should be discarded from dataset due to known maintenance, instrument malfunction, or rain event
    ustar
    Friction velocity in meters per second (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction or poor quality measurement according to quality flag as defined in process step
    Range of values
    Minimum:0.0103
    Maximum:4.1499
    Units:m sec-1
    air_temp_3m
    Air temperature recorded at 3m height above the sediment surface with Onset HOBO Temperature/RH Smart Sensor S-THB-M00x (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction
    Range of values
    Minimum:-11.6
    Maximum:34.3
    Units:degrees Celcius
    RH
    Relative humidity recorded at 3m height above the sediment surface with Onset HOBO Temperature/RH Smart Sensor S-THB-M00x (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data due to instrument malfunction
    Range of values
    Minimum:26.2
    Maximum:100.0
    Units:percent
    PAR
    Incoming photosynthetically active radiation (PAR) in micromoles photons per meter squared per second (umol photons m-2 sec-1) recorded at 3 meter height above the sediment surface with Onset HOBO Photosynthetically Active Radiation Smart Sensor S-LIA-M003 (Source: Producer Defined)
    ValueDefinition
    << empty cell >>No Data
    Range of values
    Minimum:1.2
    Maximum:2197.9
    Units:umol photons m-2 sec-1

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Rebecca Sanders-DeMott
    • Meagan Eagle
    • Kevin Kroeger
    • Faming Wang
    • T. Wallace Brooks
    • Jennifer A. O'Keefe Suttles
    • Sydney Nick
    • Adrian Mann
    • Jianwu Tang
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Rebecca Sanders-Demott
    U.S. Geological Survey, NORTHEAST REGION
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2255 (voice)
    rsanders-demott@usgs.gov

Why was the data set created?

Eddy covariance measurements of net ecosystem exchange of carbon dioxide and methane were collected continuously at half-hourly intervals to assess the magnitude and drivers of carbon exchange in an impounded coastal wetland. Data were also collected to inform predictive models of carbon fluxes across coastal wetlands of varying salinity and to facilitate National Park Service restoration planning and future blue carbon project assessments.

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: 01-Jun-2021 (process 1 of 4)
    An eddy covariance system was originally installed at the Herring River site in 2017 (2017-2020 data not available at time of this publication) to collect ecosystem scale measurements of CO2 and CH4 fluxes across the land surface (tower is part of the Ameriflux network code US-HRP). A tripod tower was equipped with a LI-7500A open path CO2/H2O analyzer (LI-COR, Inc., Lincoln, NE, USA) and a LI-7700 open path CH4 analyzer (LI-COR, Inc., Lincoln, NE, USA), along with a CSAT-3 3D sonic anemometer (Campbell Scientific, Logan, UT, USA). Instruments are deployed at 4.4 m height above the ground surface, along with a suite of meteorological sensors that measure air temperature and humidity (Onset HOBO Temperature/RH Smart Sensor (S-THB-M00x), Bourne, MA, USA), incoming photosynthetically active radiation (PAR; Onset HOBO Photosynthetically Active Radiation Smart Sensor S-LIA-M003, Bourne, MA, USA), and precipitation (Onset HOBO Rain Gauge Smart Sensor S-Rgx-M002, Bourne, MA, USA). Anemometer and gas analyzer data were collected at a frequency of 10 Hz and ancillary meteorological data were collected every five minutes. Data were downloaded every 3-4 weeks as compressed .ghg files from the anemometer and gas analyzers and as .csv files for the ancillary meterological sensors. Person who carried out this activity:
    Rebecca Sanders-Demott
    U.S. Geological Survey, NORTHEAST REGION
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2255 (voice)
    rsanders-demott@usgs.gov
    Date: 01-Jun-2021 (process 2 of 4)
    Half hourly fluxes of CO2 and CH4 were computed from the covariation of high frequency vertical wind direction and CO2 and CH4 concentration using the EddyPro software package (Version 7.0.6, LICOR, Inc., Lincoln, NE, USA), as well as latent heat exchange and friction velocity. Within software specifications, raw high frequency data were despiked and a double coordinate rotation was applied to anemometer measurements along with a flux correction for the effects of humidity on sonic air temperature, high-frequency and low-frequency spectral attenuations, and air density fluctuations coupled to instrument-related sensible heat flux in the winter. Computed fluxes were exported to .csv files. We report fluxes of carbon dioxide as net ecosystem exchange (NEE), where negative values for both NEE and CH4 indicate net uptake of gas by the land surface and positive values indicate net loss of gas to the atmosphere. We removed low quality measurements (ranked as less than or equal to 1 quality flag per EddyPro based on Mauder and Foken, 2006), measurements made during and immediately following precipitation events, and any measurement collected during site maintenance or known instrument malfunction. We also removed measurements made during low‐turbulence conditions with potential advective losses and when friction velocity, ustar, was below a site specific threshold of 0.118 meters per second calculated in the R-based software package REddyProc (Version 1.2.2, Wutzler and others 2018). Instrument malfunction caused a gap in some meteorological data from late-January through mid-April 2021 and are represented as blanks in the data. The .csv files containing the meterological data and the .csv file containing the computed fluxes were matched by datetime and merged in R.
    Wutzler, T., Lucas-Moffat, A., Migliavacca, M., Knauer, J., Sickel, K., Šigut, L., Menzer, O., and Reichstein, M., 2018, Basic and extensible post-processing of eddy covariance flux data with REddyProc: Biogeosciences Discussions, February, 1–39. https://doi.org/10.5194/bg-2018-56.
    Mauder, M., and Foken, T., 2006, Impact of post-field data processing on eddy covariance flux estimates and energy balance closure: Meteorologische Zeitschrift, vol. 15, p. 597-609 Person who carried out this activity:
    Rebecca Sanders-Demott
    U.S. Geological Survey, NORTHEAST REGION
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2255 (voice)
    rsanders-demott@usgs.gov
    Date: 15-Sep-2020 (process 3 of 4)
    Latitude, longitude and elevation of the eddy covariance tower was measured with a Trimble Real-Time Kinematic (RTK) GPS. Accuracy was 2-3 cm according to instrument corrections. Data files were exported from the instrument via a .csv file and appended to the data file of calculated fluxes via R.
    Date: 01-Jun-2022 (process 4 of 4)
    Measurements were continued as described above from May 2021 to May 2022. All new data were processed as described above and 17308 records were appended to the original dataset (17568 records) bringing the total dataset to 34876 records and revising the end date of the dataset from May 23, 2021 to May 18, 2022. In addition, newly available data was added to blank columns in the last 71 rows of the original dataset, but the original dataset is otherwise unchanged and no existing data values were modified. The metadata was updated to reflect the new ranges of values. Person who carried out this activity:
    Rebecca Sanders-Demott
    U.S. Geological Survey, NORTHEAST REGION
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2255 (voice)
    rsanders-demott@usgs.gov
  3. What similar or related data should the user be aware of?
    Sanders-DeMott, Rebecca, Eagle, Meagan J., Kroeger, Kevin D., Wang, Faming, Brooks, Thomas W., O'Keefe Suttles, Jennifer A., Nick, Sydney K., Mann, Adrian G., and Tang, Jianwu, 2022, Impoundment increases methane emissions in Phragmites-invaded coastal wetlands: Global Change Biology DOI:10.1111/gcb.16217, Wiley, Hoboken, New Jersey.

    Online Links:

    Jennifer A. O'Keefe Suttles, Eagle, Meagan J., Sanders-DeMott, Rebecca, Nick, Sydney K., Brooks, Thomas W., Mann, Adrian G., and Kroeger, Kevin D., 2022, Continuous Water Level, Salinity, and Temperature Data from Coastal Wetland Monitoring Wells, Cape Cod, Massachusetts: data release DOI:10.5066/P9T1KOTW, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Provides continuous data on water level, salinity, and water temperature concurrent with eddy covariance data presented in this data release.

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

  1. How well have the observations been checked?
    The LI-7200A Open Path CO2 /H2O Gas Analyzer has an accuracy within 1 percent of reading for carbon dioxide (CO2) and within 2 percent of reading for water (H2O) vapor. The LI-7700 Open Path CH4 Gas Analyzer has a resolution of 5 ppb at 10 Hz and 2000 ppb methane (CH4). The instrument calibration was checked using laboratory calibration gases prior to field measurements in spring 2020 and approximately every three months in the field using calibration gases. Fluxes were computed using EddyPro software (Version 7.0.6) and additional details on QA/QC are outlined in the Process Step 1. Manufacturer's specifications for the HOBO Temperature/RH Smart Sensor (S-THB-M00x) are accuracy of 0.2 degrees C over 0 degrees to 50 degrees C and +/- 2.5 percent from 10 percent to 90 percent RH (typical), to a maximum of +/- 3.5 percent. Accuracy of the PAR sensor +/- 5 micromoles per meter squared per second and resolution of the photosynthetically active radiation (PAR) sensor is 2.5 micromoles per meter squared per second. Relative humidity (RH) sensor was enclosed within a solar radiation shield and deployed on a mast with other meteorological sensors. No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
    Latitude and Longitude were measured at the base of the tower by Trimble Real-Time Kinematic (RTK) GPS. Recorded Horizontal Dilution of Position (HDOP) was 0.600 or less for all measurements. Average horizontal accuracy of this method is +/- 30 centimeters. No formal positional accuracy tests were conducted.
  3. How accurate are the heights or depths?
    Land surface elevation was measured at the base of the tower by Trimble Real-Time Kinematic (RTK) GPS. Recorded Vertical Dilution of Precision (VDOP) was 0.900 or less for all measurements. Average vertical accuracy of this method is +/- 5 centimeters. No formal positional accuracy tests were conducted.
  4. Where are the gaps in the data? What is missing?
    Gaps in the continuous data record for a given parameter may have been the result of one of several sources: sensor not deployed during that time period, vandalism of an instrument by humans or destruction by chewing animals, removal of an instrument for maintenance, corrupt data file due to malfunctioning instrument, poor data quality. Description of data filtering in included in process step. Exclusions of data from the continuous record are coded as blank cells.
  5. How consistent are the relationships among the observations, including topology?
    Each logged parameter set was queried for maximum and minimum values to be sure logged data fell within expected ranges for the environmental conditions.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None. Please see 'Distribution Info' for details.
Use_Constraints None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations.
  1. Who distributes the data set? (Distributor 1 of 1)
    ScienceBase
    U.S. Geological Survey
    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? The dataset contains one CSV file containing the data (phragmites_eddycovariance_ver2.csv), the browse graphic (phramites_eddycovariance.jpg), and the FGDC CSDGM metadata in XML format.
  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?
  5. What hardware or software do I need in order to use the data set?
    The dataset includes a comma-delimited text file. The user must have software capable of opening the text file and reading the data formats.

Who wrote the metadata?

Dates:
Last modified: 15-Jun-2022
Metadata author:
Rebecca Sanders-DeMott
Northeast Region: WOODS HOLE COASTAL AND MARINE SCIENCE CENTER
384 Woods Hole Road
Woods Hole, MA
US

508-548-8700 x2255 (voice)
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 USGS.
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P9RRL3T0/metadata_phramites_eddycovariance_ver2.faq.html>
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