Monitoring the health of our oceans demands robust, precise, reliable and affordable methods for monitoring pH levels. Accurate and timely pH monitoring is critical for understanding the impact of ocean acidification and other environmental changes. Studies of ocean acidification are recommended to be based on measurements of pH on the total scale, due to accounting for sulphate ion influence. Providing autonomous real-time pH monitoring on the total scale offers global comparability and facilitates the assessment of long-term trends, making it a vital tool for understanding and addressing ocean acidification and environmental change.

Traditional pH measurement methods have limitations, such as sensitivity to alterations of ionic strength and the use of complex spectrophotometric systems with long sampling times and generation of chemical waste. Optical pH sensors for total scale are a viable alternative to traditional pH measurement for global pH monitoring. Our pH sensor for the total scale are based on a unique optical detection principle (REDFLASH technology) and feature an outstanding low cross-sensitivity to ionic strength in marine waters, as well as an excellent sensitivity in the marine pH range of 7-9.

With the next generation optical pH sensors from PyroScience sensitive measurements of ocean pH on the total scale can be performed even under harsh deep-sea conditions down to 4000m water depth. For this, the total scale pH sensor cap PHCAP-PK8T-SUB fits on our deep sea AquapHOx© long-time logger APHOX-LX and real-time data transmitter APHOX-TX for global pH deep sea monitoring.

For shallow-water pH monitoring, an easily replaceable set of underwater sensor protection is available. This includes sensor protection cage APHOX®-CAGE-AF with an anti-biofouling net for shallow-water AquapHOx®-Logger and -Transmitters and anti-biofouling net APHOX®-CAP-AF for the sensor cap protection cage of the PHCAP-PK8T-SUB sensor cap. The combination of both helps to protect the sensor system from the accumulation of marine organisms and biofouling. 

Beside underwater systems we also offer lab systems based on the flexible multi-channel PC-operated fiber-optic meter FireSting©-PRO for experiments in mesocosms or under controlled conditions in the lab or onboard a vessel with freshly collected seawater samples, using total scale pH miniprobes or sensor spots with contactless sensor read-out for chamber incubations in situ or in the lab/onboard.

Contact us to explore how our optical pH sensors can enhance your oceanic pH monitoring capabilities.

Applicable Sensor Types for Underwater AquapHOx devices

• pH sensor cap with underwater connector PHCAP-PK8T-SUB
• Fiber-based pH screw cap probe with underwater connector PHROBSC-PK8T-SUB
• pH sensor spots PHSP5-PK8T for integration into incubations chambers with SPFIB-LNS-SUB for contactless read-out

Applicable Sensor Types for Lab FireSting-PRO devices

• Fiber-based pH screw cap probe PHROBSC-PK8T
• pH sensor spots PHSP5-PK8T for integration into incubations chambers with SPFIB-LNS for contactless read-out

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Related Publications

• ECO magazine, Spring Issue 2022 : Compact, flexible and easy-to-use sensor technology for ocean measurements of pH and oxygen
• ECO magazine 2023, Deep Dive I Ocean Observation: Autonomous Sensor Solutions for Ocean pH and Oxygen Observations

Related Peer-Reviewed Publications

Autonomous high-frequency time-series observations of total alkalinity indynamic estuarine waters
Qiu et al. 2023, Marine Chemistry
https://doi.org/10.1016/j.marchem.2023.104332