Abstract Recently, a new monitoring philosophy “soundscape” which uses passive acoustics as an efficient way of, among others, monitoring animal visitation times, relative densities, and potential anthropogenic influences, is becoming relevant in scientific community. Our vision is to make feasible the deployment of large swarms of miniature drifters/gliders to enable new insights into physical–biological dynamics of the deep ocean. The technology to develop a miniature drifter (volume below 1L) will be the main focus. We will demonstrate that miniaturized, low-cost and reliable devices can be successfully deployed, opening the way to the development of large swarms of such miniature devices for deep ocean surveying.

GPS and Satellite antennas for surface communications

Electronics

Energy

Salt Ballast

Hydrophone Arrays

Floater

Deep Sea CTD and soundscape Device: • Be environmentally friendly and non-invasive; • Be simple, reliable and low cost; • Possess high autonomy and energy harvesting capabilities.

The expected achievements: • PVDF hydrophones: up to 200 kHz and 4000m depth; • High-Pressure Tolerant Electronics; • Low cost 3D printing and molding; • Natural salt ballast release used to emerge the device.

PVDF Hydrophone arrays characteristics:

• Wide frequency range – from mHz to GHz; • Wide dynamic range – from μ bar to Mbar; • Low acoustic impedance – close to water; • High mechanical strength and impact resistance; • High stability resisting moisture; • Can be fabricated into unusual flexible designs:

Expected Advantages/Disadvantages: + Environmental friendly, no Lead is used; + Simplicity of design (no pressure release system); + Mechanical flexibility; + Ease of making unusual geometries; + Good acoustic impedance match to water; + Broad bandwidth; + Potentially lower cost; - Low Piezoelectric coefficient; - Requires a charge amplifier.

M.S.Martins1, L.M. Goncalves1, P.A. Gomes2, T Miranda3, E.N.B. Pereira3, and E. Fernández4 1CMEMS-UMinho, University of Minho, Campus of Azurém, Guimarães, Portugal 2Molecular and Environmental Biology Centre, Universidade do Minho, Portugal

3ISISE – Dep. of Civil Engineering, University of Minho, Portugal 4Dpt. of Animal Ecology and Biology, University of Vigo, Spain

E-mail: mmartins@dei.uminho.pt

2DeepScape Towards deep sea soundscaping