CHAPTER 7: Optical O₂ Sensing in Aquatic Systems and Organisms

Optical O₂ measurements with fiber-optic, planar or particle-based opt(r)odes have become widespread in aquatic science since the first O₂ microopt(r)odes were introduced in 1995. A wide variety of measuring systems are now available both for lab-based and in situ field measurements at spatial scales ranging from µm to m’s, and temporal scales ranging from <1 s to several months. Furthermore, the market has seen an explosion in commercially available optical O₂ sensor and measuring systems, which complement or have replaced electrochemical O₂ sensors in several areas of application. In this chapter, we give a broad overview of measuring schemes and instruments used for optical O₂ sensing, and illustrate their application in various aquatic environments. We also address demands and challenges related to optical O₂ sensing in aquatic systems.