by Robert Mills, JASCO Applied Sciences
December 6, 2018
Hello, I’m Robert Mills, Senior Field Technician for JASCO Applied Sciences. I’m on board NOAA Ship Okeanos Explorer to deploy a deepwater acoustic mooring. I’m part of the multibeam sonar soundscape study for University of New Hampshire.
Our mooring has two of JASCO’s AMARs (Autonomous Multichannel Acoustic Recorders). The AMARs will record the sound projected by various multibeam configurations. We can use this information to better understand the sound signature of the sonar and its effect on the environment.
AMARs are highly sensitive acoustic recorders that are entirely autonomous of a deck control system. They can record soundscapes for months on end. JASCO’s recorders are used worldwide for precisely measuring all kinds of sound sources in the ocean.
For this array, we’re using AMAR UDs (Ultra Deeps) that can submerge to over 6,000 meters (3.7 miles). They are housed in strong glass sphere, with each AMAR having two hydrophones. Each hydrophone has a different sensitivity so we can listen to different characteristics of the Okeanos Explorer’s multibeam sonar.
At the end of the study, I’ll use two tandem acoustic releases that trigger the mooring to detach from its anchor. The mooring will float to the surface, and the deck crew and I will pull it back onboard and collect the data.
December 7, 2018 update: We successfully recovered the hydrophone array after acoustically releasing it from its mooring on the seafloor.