Monitoring Ocean Dynamics Through Sound

Jennifer L. Miksis-Olds, University of New Hampshire 

Sound is the predominant long-range sensory modality in the ocean because sound transmits more efficiently than visual or chemical signals in the marine environment.  Humans and marine animals have come to depend on sound signals for communication, navigation, and foraging.  Remotely deployed passive acoustic technology provides a time series or a continuous record of the sound level in an area of region.  Processing of passive acoustic datasets provides information on ocean weather and sea state, ice presence, animal presence, and human activity.  Remotely deployed active acoustic systems provide a time series of acoustic backscatter relating to oceanographic features, zooplankton/fish presence and abundance, and community structure. Combining these two types of acoustic systems provides the user a powerful tool to address ecosystem scale questions at high temporal resolution.   Application of acoustic remote sensing systems will be described from ongoing regional work in the Bering Sea and the Outer Continental Shelf off the SE coast of the US.  Global work utilizing the hydrophone recordings from the Comprehensive Nuclear-Test Ban Treaty International Monitoring System will highlight changes in ocean dynamics over a multi-year to decadal time period.