The CONTROS HydroC® CO₂ sensor is a unique and versatile subsea / underwater carbon dioxide sensor for in-situ and online measurements of dissolved CO₂. The CONTROS HydroC® CO₂ is designed to be used on different platforms following different deployment schemes. Examples are moving platform installations, such as ROV / AUV, long-term deployments on seabed observatories, buoys and moorings as well as profiling applications using water-sampling rosettes.