The pH instruments on the Cabled Array are SAMI-pH sensors provided by Sunburst. These sensors measure pH (total concentration of hydrogen ions) in the marine environments spanning the Cabled Array.
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, it represents about a 30% increase in H+ ion concentration and is already impacting marine organisms and the shellfish industry.
Cabled Array pH sensors, which complement the pCO2 measurements, are installed on Shallow Profiler Mooring profiling science pods and on the static Platform Interface Assemblies at Axial Base, the Offshore site, and at Slope Base. They are also a component of the Benthic Experiment Platforms at the Oregon Offshore and Shelf sites.