Seawater Carbon Sensing
Developing New Technologies to Measure CO2
Zhaohui “Aleck” Wang
Associate Scientist, Marine Chemistry and Geochemistry Department
Levels of carbon dioxide (CO2) in ocean water are directly affected by levels of atmospheric CO2—increasing levels of atmospheric CO2 are acidifying the ocean and affecting marine chemistry and ecosystems. Therefore, collecting precise measurements of marine CO2 is essential. With support from the Vetlesen Foundation, my team and I are developing a miniaturized in situ sensor we call the Channelized Optical System II (CHANOS II) to capture, in up to 1,000 meters depth, the measurements of two key parameters needed to study the marine carbon system: dissolved organic carbon (DIC) and partial pressure of carbon dioxide (pCO2).
Building and improving on the original CHANOS, which makes simultaneous measurements of seawater DIC and pH, the new sensor will expand CHANOS’s capability and will dramatically reduce sensor size, power consumption and cost, while improving the CO2 exchange mechanism and overall robustness of the sensor. The original CHANOS can be deployed on stationary platforms such as buoys or used in underway measurements on profilers or autonomous underwater vehicles (AUVs) for up to two months before maintenance. However, upon its completion, the CHANOS II will be capable of making precise measurements on both stationary and mobile platforms for time-series deployments longer than 4 months or profiling measurements on mobile platforms for a weeks at a time. CHANOS II will be the first in situ sensor capable of fully resolving the CO2 system in a single instrument package, making it better positioned for commercialization and thus more readily available to the public for a variety of uses.