|Hofmann, Gretchen E.||University of California-Santa Barbara (UCSB)||Principal Investigator|
|Hoshijima, Umihiko||University of California-Santa Barbara (UCSB)||Contact|
|Biddle, Mathew||Woods Hole Oceanographic Institution (WHOI BCO-DMO)||BCO-DMO Data Manager|
All methods are described in Kapsenberg et al. (2015). Data were collected using an autonomous SeaFET pH sensor containing Honeywell DuraFET electrodes (Martz et al., 2010). Sensor depth was 18 m with ~27 m bottom depth. Sensors sampled on a 4-hour frequency.
Conversion from voltage to pH (on a total scale) was performed using a single discrete calibration sample collected via SCUBA using a 5 L GO-FLO sampling bottle. Sample collection was conducted within the first two weeks of sensor deployment, after sensor conditioning to seawater, in-situ. Samples were preserved with saturated mercuric chloride Standard Operating Procedure (SOP) 1 (Dickson et al., 2007) and analyzed for spectrophotometric pH (total scale, at 25 degrees Celsius) and total alkalinity following SOP 6b and 3b (Dickson et al. 2007). Sample salinity was measured using a calibrated YSI 3100 Conductivity Instrument. In-situ pH was calculated using the program CO2Calc [Version 1.0.1, 2010, U.S. Geological Survey] using SeaFET temperature recorded at the time of sample collection.
SeaFET thermistors were not individually calibrated resulting in a maximum estimated temperature offset of ~0.3 degrees Celsius.
All processing was conducted in R (v.3.5.1) using seacarb (v.3.2.8) to generate calibration coefficients for the sensor that were later applied to the datset.
BCO-DMO Processing Notes:
- appended lat, lon, sensor_depth, and water_depth columns to include spatial information with the data.
- removed first column as it was an index for the row number.
|time||date and time of collection in yyyy-mm-dd HH:MM:SS format||unitless|
|temp||water temperature||degrees Celsius|
|lat||latitude in degrees north||decimal degrees|
|lon||longitude in degrees east||decimal degrees|
|Dataset-specific Instrument Name|| |
|Generic Instrument Name|| |
|Dataset-specific Description|| |
Instruments are SeaFET® sensors using a Honeywell DuraFET® electrode, as well as a Thermo Cl-ISE as an external reference for data quality control. (Martz et al, 2010).
|Generic Instrument Description|| |
The SeapHOx and SeaFET are autonomous sensors originally designed and developed by the Todd Martz Lab at Scripps Institution of Oceanography. The SeaFET was designed to measure pH and temperature. The SeapHOx, designed later, combined the SeaFET with additional integrated sensors for dissolved oxygen and conductivity. Refer to Martz et al. 2010 (doi:10.4319/lom.2010.8.172). The SeapHOx package is now produced by Sea-Bird Scientific and allows for integrated data collection of pH, temperature, salinity, and oxygen. Refer to Sea-Bird for specific model information.
|Start Date|| |
|End Date|| |
Overwinter 2013-2014, Cape Evans Site Nearshore mooring by McMurdo Station, Ross Sea, Antarctica. (77˚ 38.053’ S, 166˚ 24.880’ E, 28m bottom depth)