Deployment of an in-situ pH calibrator on MARS cabled ocean observatory

A recently developed in situ pH measurement and calibration system (pH Calibrator) has been deployed on MARS (Monterey Accelerated Research System) cabled ocean observatory located at Monterey Bay, California. The deployment took place at the depth 880 m, and lasted for more than two months. A key aspect of the instrument is user-defined auto-calibration, enhancing the accuracy of pH measurements in harsh, high-pressure environments, over long intervals, as reported here. Thus, the instrument takes full advantage of cable power and internet connectivity permitting real-time monitoring of pH, with calibration scheme optimized to achieve specific scientific objectives in response to local environmental factors. Here we report recent modifications to the instrument, which enhanced its effectiveness during the MARS cabled ocean observatory deployment.