University of Delaware sonar technician Peter Barron prepares to lower a device that will measure the speed of sound throughout the entire water column.
Peter Barron
Image courtesy of NOAA, Thunder Bay National Marine Sanctuary. Download larger version (jpg, 6.1 MB).

University of Delaware sonar technician Peter Barron prepares to lower a device that will measure the speed of sound throughout the entire water column. These sound velocity profiles were collected once every four hours during the entire survey.

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