The Flanders Marine Institute, (VLIZ) seized upon the quiet of lockdown to map the underwater soundscape of the Belgian section of the North Sea.

Using its near silent AutoNaut USV research vessel, Adhemar, VLIZ has been able to record current noise levels, which will be compared with the marine soundscape once normal sea traffic and marine activities recommence. This will help to determine the impact of manmade noise on natural sea life and the marine environment, building a picture of the marine soundscape in conditions that may never again be possible.

Following a 15% fall in shipping intensity in the North Sea since the start of the pandemic, VLIZ put its AutoNaut USV robot Adhemar into action to carry out measurements of the underwater noise in the turbid and shallow coastal waters of Ostend-Bredene.

Using Seiche’s MicroPAM monitoring and mitigation system, developed specifically for autonomous surface vehicles (USVs), underwater sound was captured using two hydrophones trailed on an 8m in-water cable with depth sensor. The onboard Seiche electronics module acquired and recorded all data.

Supported by AutoNaut’s wave foil propulsion technology, which produces virtually no underwater noise, VLIZ utilised its USV Adhemar as a non-invasive, flexible method of capturing sound data, deploying Seiche Passive Acoustic Monitoring (PAM) technology to build a sound-map of the waters for future comparison.

By Jake Frith

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