Optical gas monitoring in sea water: Robust reliable and highly flexible

This paper describes our progress towards the development of field deployable pCO₂ and NH₃ in water measurement technologies. The fluorescence lifetime based pCO₂ technology described here has a wide dynamic range of 10²-5 × 10⁴ microatmospheres and has undergone numerous field trials that indicate suitability to a wide range of short and long term monitoring applications. The spectrophotometric NH₃ technology described is in an earlier stage of development, and the characterization experiments performed to date show that the technology responds reversibly to ammonia concentrations at the low ppb level and could therefore be applicable to a wide range of applications within aquaculture and oceanography. The pCO₂ and NH₃ sensor prototypes used in these investigations are based on the same mechanical platform, that in future could also form the basis for other water quality monitoring technologies.