Instrument: ISUS Nitrate sensor
The Satlantic ISUS nitrate sensor is an in-situ UV absorption sensor which calculates nitrate concentration from the seawater spectrum. The ISUS V2 has a 1cm path length, a 200-400 nm wavelength range., and is depth rated to 1000 m. Satlantic's ISUS V3 nitrate sensor uses advanced UV absorption technology to measure nitrate concentration in real-time.
A SUNA nitrate sensor rated to 500-m depth was used (reported in the 'nitrate_SUNA' column). See the SUNA Manual (PDF).