Nearshore pH and temperature at mooring sites in McMurdo Sound, Antarctica, Overwinter 2011-2012

Data Type: Other Field Results
Version: 1
Version Date: 2019-01-28

» Linking natural variability and anthropogenic changes in pH and temperature to performance in calcifying Antarctic marine invertebrates (OA pH, Temp, Calc Inverts)
Hofmann, Gretchen E.University of California-Santa Barbara (UCSB)Principal Investigator
Hoshijima, UmihikoUniversity of California-Santa Barbara (UCSB)Contact
Biddle, MathewWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager


Spatial Extent: Lat:-77.63422 Lon:166.41467
Temporal Extent: 2013-11-12 - 2014-10-23

Dataset Description

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.

Acquisition Description

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. 

Processing Description

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.

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Related Publications

Bresnahan, P. J., Martz, T. R., Takeshita, Y., Johnson, K. S., & LaShomb, M. (2014). Best practices for autonomous measurement of seawater pH with the Honeywell Durafet. Methods in Oceanography, 9, 44–60. doi:10.1016/j.mio.2014.08.003
Dickson, A.G. (2001). Reference materials for oceanic measurements. Oceanography, 14(4), 21-22.
Kapsenberg, L., Kelley, A. L., Shaw, E. C., Martz, T. R., & Hofmann, G. E. (2015). Near-shore Antarctic pH variability has implications for the design of ocean acidification experiments. Scientific Reports, 5(1). doi:10.1038/srep09638
Liu, X., Patsavas, M. C., & Byrne, R. H. (2011). Purification and Characterization of meta-Cresol Purple for Spectrophotometric Seawater pH Measurements. Environmental Science & Technology, 45(11), 4862–4868. doi:10.1021/es200665d
Martz, T. R., Connery, J. G., & Johnson, K. S. (2010). Testing the Honeywell Durafet® for seawater pH applications. Limnology and Oceanography: Methods, 8(5), 172–184. doi:10.4319/lom.2010.8.172

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ididentifier unitless
timedate and time of collection in yyyy-mm-dd HH:MM:SS format unitless
pHpH total units
tempwater temperature degrees Celsius
latlatitude in degrees north decimal degrees
lonlongitude in degrees east decimal degrees
water_depthbottom depth meters
sensor_depthsensor depth meters

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Dataset-specific Instrument Name
SeaFET sensors
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.

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McMurdo Station
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)

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Project Information

Linking natural variability and anthropogenic changes in pH and temperature to performance in calcifying Antarctic marine invertebrates (OA pH, Temp, Calc Inverts)

Coverage: McMurdo Sound, Antarctica

Abstract: The research supported in this project will examine the effects of environmental change on a key Antarctic marine invertebrate, a pelagic mollusk, the pteropod, Limacina helicina antarctica. There are two main activities in this project: (1) to deploy oceanographic equipment, in this case, autonomously recording pH sensors called SeaFETs and other devices that record temperature and salinity, and (2) to use these environmental data in the laboratory at McMurdo Station to study the response of the marine invertebrates to future changes in water quality that is expected in the next few decades. Notably, changes in oceanic pH (aka ocean acidification) and ocean warming are projected to be particularly threatening to calcifying marine organisms in cold-water, high latitude seas, making tolerance data on these organisms a critical research need in Antarctic marine ecosystems.  These Antarctic shelled-animals are especially vulnerable to dissolution stress from ocean acidification because they currently inhabit seawater that is barely at the saturation level to support biogenic calcification. Indeed, these polar animals are considered to be the 'first responders' to chemical changes in the surface oceans. Thus, this project will lead to information about the adaptive capacity of L. helcina antarctica. From an ecological perspective this is important because this animal is a critical part of the Antarctic food chain in coastal waters and changes in its abundance will impact other species. Finally, the research conducted in this project will serve as a training and educational opportunity for undergraduate and graduate students as well as postdoctoral scholars.

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Funding SourceAward
NSF Antarctic Sciences (NSF ANT)

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