Underwater Sensors for Ecosystem Monitoring

Underwater sensing technologies have become fundamental tools for acquiring continuous, high-resolution information on the condition and functioning of marine ecosystems. This chapter provides a comprehensive examination of contemporary sensor systems designed to measure physical, chemical, and biological variables across diverse aquatic settings. It highlights recent progress in optical, acoustic, biogeochemical, and multifunctional sensing platforms, alongside advances in autonomous deployments and low-power data acquisition. Particular attention is given to how these technologies enhance long-term monitoring, early detection of environmental stressors, and the refinement of predictive ecological models. Operational challenges—such as sensor calibration, biofouling, data reliability, and integration within broader observing networks—are critically assessed. Overall, the chapter underscores the increasingly indispensable role of underwater sensors in supporting evidence-based ocean conservation and sustainable ecosystem management.