The OOI pCO2 sensor (Sunburst SAMI-CO2) measures the partial pressure of carbon dioxide (pCO2) from 150-700 μatm in the upper 200 m of the water column. The distribution of pCO2 is dependent on: (1) increases due to gas exchange with the atmosphere at the ocean surface, (2) removal by photosynthesis, (3) removal by calcium carbonate formation, (4) removal by solar heating, (5) increases from breakdown of plant material by microbial processes, and (6) addition due to dissolution of calcium carbonate. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms, such as oysters. Carbon dioxide concentrations are increasing in the atmosphere due to the use of fossil fuels, and the increase in atmospheric CO2 is about 30 times higher than at any time in the past geological history of the Earth. The oceans are absorbing about 30% of the atmospheric CO2, resulting in a shift in seawater acid-base chemistry and a decrease in ocean pH (more acidic). These chemical changes are termed “ocean acidification”.

(some 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
Optical Absorbance Ratio at 434nm CO2ABS1
Optical Absorbance Ratio at 620nm CO2ABS2
PCO2W Thermistor Temperature CO2THRM
Partial Pressure of CO2 in Water PCO2WAT DPS

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

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.

Class-Series Make Model
PCO2WA Sunburst SAMI-pCO2
PCO2WB Sunburst SAMI-pCO2
PCO2WC Sunburst SAMI-pCO2 - inductive

Primary Science Discipline


Research Themes

Access Data

PCO2W on the Data Portal