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Seawater pH

Seawater pH sensors measure the total concentration of hydrogen ions in a solution. The OOI pH sensor (Sunburst SAMI-pH) measures pH (total hydrogen scale) in the marine pH range of 7-9. For tens of millions of years, Earth’s oceans have maintained a relatively stable pH level. However, since the beginning of the industrial revolution in the 1800s, the surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14. While this may seem to be a very small change in pH, it represents about a 30% increase in H+ ion concentration, and is already impacting marine organisms and the shellfish industry.

(text courtesy of Interactive Oceans)

Data Products

This instrument measures the following data products. Select a data product's name to learn more.

Data Product Code DPS
PHSEN Thermistor Temperature ABSTHRM
Optical Absorbance Signal Intensity at 434nm PH434SI
Optical Absorbance Signal Intensity at 578nm PH578SI
pH PHWATER DPS

The algorithm code used to generate data products for this instrument is also available in the ion-functions GitHub repository.

Algorithm Code

Instrument Models & Deployed Locations

The OOI includes the following instrument makes and models for this instrument type. Follow the links below to find out where in the OOI this instrument has been deployed. You'll also find quick links for each instrument to Data portal, where you can plot and access data.

Series Make Model
PHSENA Sunburst SAMI-pH
PHSEND Sunburst SAMI-pH
PHSENE Sunburst SAMI-pH- inductive
PHSENF Sunburst SAMI-pH
Sunburst Sensor’s Submersible Autonomous Moored Instrument collects pH and pCO2 measurements for OOI. Photo credit: Sunburst Sensors, LLC

Sunburst Sensor’s Submersible Autonomous Moored Instrument collects pH and pCO2 measurements for OOI. Photo credit: Sunburst Sensors, LLC

Primary Science Discipline
Chemical