We are pleased to share that the next edition of ICOS Talks will feature Tobias Steinhoff (GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel) presenting the ICOS Ocean Thematic Centre pCO2 instrument intercomparison, a major study comparing 27 instruments used for surface ocean pCO2 measurements. If you are working in ocean acidification, marine carbon monitoring, or sensor tech, you will not want to miss this upcoming webinar.
To join the webinar, register here
Tobias Steinhoff (co-Chair of SOCONET) will dive into the results of a rigorous two-week experiment conducted at the VLIZ - Flanders Marine Institute lab facilities. Learn exactly how current pCO2 instruments perform and respond when pushed across wide ranges of temperature and pCO2 levels.
About the speaker
Tobias Steinhoff is a chemical oceanographer at GEOMAR Helmholtz Centre for Ocean Research Kiel specializing in the ocean’s carbon, nutrient, and oxygen cycles. He is operating the Ship-of-Opportunity (SOOP) line DE-SOOP-Atlantic Sail in the North Atlantic Ocean. For more than two decades, he has contributed to international ocean observations and research expeditions across the Atlantic, Pacific, and Indian Oceans. Between 2019 and 2024, he supported ICOS Oceans and led the international pCO2 instrument inter-comparison in 2021. His current focus is on new technologies, autonomous sensors, and international collaborations to improve global ocean observations and data accessibility.
Want to read up before the session? Check out the landmark paper published in late 2025 here.
Abstract
In 2021, the Ocean Thematic Centre of ICOS conducted an international inter-comparison of ocean pCO2 instruments including direct air–water equilibration systems, membrane-based flow-through instruments, submersible sensors, and buoy-mounted systems. They were tested in a tank facility using natural North Sea water, where temperature and pCO2 were systematically varied. Instruments were compared against an inter-comparison reference pCO2 during stable conditions. The study does not recommend specific sensors but results indicate that direct air–water equilibration is generally more consistent and less influenced by external factors than membrane-based or photometric methods. Missing or uncalibrated temperature measurements were identified as a major source of uncertainty.