Autonomous Hydrophones at NOAA/OSU and a New Seafloor Sentry System for Real-time Detection of Acoustic Events

Development is under way of a new intelligent autonomous hydrophone system, the Quasi-Eulerian hydrophone, or QUEphone. A tether-free portable hydrophone float with built-in data processor, it is capable of repeated vertical ascents and descents from seabed to surface using an internal buoyancy controller. While on the seafloor, it runs an acoustic event detection algorithm continuously; upon detection of a significant acoustic event, or at regular intervals, it surfaces to transmit its position at the surface and a small data file to shore via satellite. Issues of detecting acoustic events at low false alarm rate and applications of this new technology to monitoring other geochemical, biological, and oceanographic properties associated with the world´s ecosystem are discussed. Float payload, depth limitation, and vertical travel speed are also discussed