Distributed acoustic sensing for underwater passive acoustic monitoring of biophonic, geophonic, and anthropogenic sources—Universityof Washington Lab tour

Anthropogenic noise in the ocean is one of the many stressors affecting marine biodiversity. Knowing animals and ships locations is key to conservation efforts. Geophony is also of research interest, as T-phases analysis can help to characterize ocean seismicity and measure ocean temperature. However, offshore passive acoustic monitoring remains challenging and expensive, necessitating continuous advancements in technology. Distributed Acoustic Sensing (DAS) is one possible complement that leverages existing infrastructure to provide continuous acoustic data from the seafloor in near-real-time, at an onshore facility. DAS uses fiber-optic cables as sensors, offering capabilities comparable to an array of thousands of directional hydrophones, whose sampling frequencies depend on the longest probing distance. Various datasets are presented here, including those from the fiber connection between Seattle and Bothell, the Ocean Observatories Initiative’s Regional Cable Array off the coast of Oregon, and the MARS cable in Monterey Bay. In this virtual lab tour, we provide an insight into the workflow, from data collection to processing and data analysis. The results of this research at the University of Washington have led to new observational efforts on land, ice, and underwater, spanning fields as diverse as oceanography, seismology, engineering, and marine ecology. [Work partially supported by ONR]