Listening to the Deep: Advancing Ocean Soundscape Monitoring with Autonomous Acoustic Technology
Project Summary
Integral engineers the world’s first autonomous deep-water profiling float capable of directional acoustic sensing.
The ocean’s soundscape carries critical information about marine mammal activity, geophysical events, and the growing presence of human activity — but sustained directional acoustic monitoring at depth has been technically out of reach. NOAA’s Office of Exploration Research identified this as a key data gap and partnered with Integral and collaborating institutions to close it. Over three years, Integral led the engineering integration of its proprietary NoiseSpotter® directional acoustic sensor with Seatrec’s infiniTE™ autonomous profiling float, producing the world’s first deep-water platform capable of capturing directional ocean acoustics over extended deployments.
Location: Santa Cruz, CA
Key Personnel
Kaustubha Raghukumar, Ph.D. Senior Consultant
Emily Barosin, E.I.T. Associate Scientist
Challenge
No technology existed for sustained directional acoustic monitoring in deep water — limiting global ocean soundscape research.
Ocean soundscapes encode patterns of marine mammal communication, ship traffic, and geophysical activity such as earthquakes and volcanic eruptions. Understanding how these soundscapes vary directionally — and how they are shifting over time in response to increasing anthropogenic pressures — requires long-duration, autonomous monitoring at depth.
The core technical barrier was the absence of a profiling float capable of both unlimited-duration deep-water operations and directional acoustic sensing. Existing platforms could capture omnidirectional sound but could not resolve where sounds were coming from, limiting the analytical value of collected data. Filling this gap was identified as a priority by NOAA to support ocean policy, environmental management, and future mitigation of noise from activities including deep-sea mining, geophysical surveying, and commercial-scale marine energy development.
Our Role
Integral led the engineering integration, field deployment, and data analysis for a novel acoustic sensing system combining its NoiseSpotter® technology with an unlimited-endurance autonomous float.
Integral brought specialized expertise in underwater acoustics, ocean engineering, and oceanography to a multi-institution team. The key innovation was integrating Integral’s NoiseSpotter®—a vector sensor capable of measuring acoustic pressure and particle velocity in three dimensions — with Seatrec’s infiniTE™ float, which uses ocean thermal energy to power indefinite-duration deep-water profiling. No prior platform combined these two capabilities.
The engineering process was methodical: the acoustic vector sensor was mechanically suspended below the float in a custom-designed cage, and individual modules were developed and tested iteratively over three years. Integral coordinated closely with collaborating institutions to incorporate proven approaches — including a float navigation technique developed at Scripps Institution of Oceanography using modeled ocean currents — while advancing the directional sensing capability beyond what any existing system provided.
What We Delivered & Results
The project produced a first-of-its-kind deep-water directional acoustic sensing platform, with a final demonstration deployment planned in Hawaiʻi.
The completed system captures acoustic pressure levels, horizontal bearing, and elevation across depth profiles to 1,000 m, providing a multidimensional view of the underwater soundscape over continuous deployment periods. Example data from a 24-hour deployment in Oceanside, CA, demonstrated the system’s ability to track changes in acoustic conditions across dive cycles.
Findings have been presented at international conferences, and a peer-reviewed publication is in preparation. The platform is positioned to support long-term monitoring campaigns that will yield insight into directional variability of ocean noise on timescales of months to years — data that will directly inform management and policy decisions for ocean noise in an era of expanding offshore activity.
Project Highlights
- First autonomous profiling float with directional acoustic sensing capability
- Successful multi-dive field demonstration validating system performance in real ocean conditions
- A scalable platform for future global ocean soundscape surveys, supporting policy and mitigation planning for marine noise from shipping, energy development, and resource extraction