Ocean Acoustics

A diverse group of oceanographers, biologists and engineers are working on a variety of topics in underwater ocean sounds, developing new technologies and methods to improve recording capabilities of ocean sounds ranging from the sea surface to the deepest depths of the ocean floor. Researchers are also developing new software techniques for bioacoustic and geophysical analysis of underwater acoustic data. Using these tools, scientists make discoveries of ocean and seafloor processes, climate related phenomenon, and marine mammal and fish behavior and ecology and strive to share this information with scientists, regulatory agencies for improved management of natural resources and the general public to improve environmental ocean literacy.

Work in this area has included the following:

• The Ocean Noise Reference Station project maintains a network of hydrophones at 12 sites within the U.S. exclusive economic zone including an array in the Terra Nova Bay (Ross Sea Antarctica) monitoring acoustic signals radiated from ice shelves and sea ice.
• Technical engineering developed a portable, under-ice acoustic winch system for recording acoustic and environmental data (conductivity, temperature, depth) in remote polar areas.
• Baleen whale calls (blue, fin, sei & humpback) were analyzed to assess calls missed by automatic detectors used by the Northwest Fisheries Science Center.
• A gray whale noise and stress project is the first to combine multiple metrics (including fecal hormone data) of baleen whale physiology to understand physiological responses to underwater noise.
• The frequency and inter-pulse interval of fin whale 20 Hz vocalizations were observed over ten years from 2003 to 2013 from bottom-mounted hydrophones and seismometers in the northeast Pacific Ocean to study the long-term stability of fin whale (Balaenoptera physalus) singing behavior. See this open access publication (pdf).
• Fin whale vocalization behavior was studied in response to long-term variations in deep ocean ambient sound across the North Pacific.
• PACES Phase II developed and tested a new methodology by using an animal-borne active acoustic tag to conduct controlled sound exposure experiments on free-ranging, naïve marine mammals in their natural habitat. Controlled sound exposure experiments are essential to evaluate the effects of anthropogenic noise on marine mammals and can help scientists and regulators understand the behavioral responses and physiological consequences of anthropogenic noise (i.e., naval sonar sounds and seismic airgun pulses).
• Advanced methods for passive acoustic detection, classification, and localization of marine mammals were developed.
• At a time when ocean noise is receiving increased global attention, researchers at OSU and NOAA have developed an effective method to use an underwater robotic glider to measure sound levels over broad areas of the sea. See this open-access publication (pdf).
• The physiological effects of changing noise levels on Pacific gray whales (Eschrichtius robustus) were measured.
• A pilot project was conducted to measure the physiological effects of noise exposure on Pacific Gray Whales (Eschrichtius robustus).
• The impacts of sound generated from human activities and natural processes on marine ecosystems were evaluated.