Project Deliverable D50 Report on Best Practices Workshop - Ifremer

4.2.2.3 Debriefing
The following text was issued by the participants to the sessions.
Some acoustic sensing physical and technological constraints
Abstract: The main distinctive feature of acoustic sensing is the production of a very large
volume of data in comparison with other standard oceanographic sensors. In addition, active
sensing requires a higher power supply than passive sensing.
The co-existence of the above acoustic applications may pose the problem of overlapping
frequency band occupation that must be addressed by synchronization processes, spatial
separation and software based-solutions.
The sensing strategy will be driven by the spatial and temporal scales of investigation, e.g.
from long-term acoustical tomography applications to the detection of geohazard events, from
the detection of individual zooplankton specimens to the imaging of the scattering layers.
In the case of standalone observatories, the power supply, computational load, data storage
and transmission (acoustic modem, satellite link, etc.) may be limiting factors for quasi realtime,
long time series acquisition and processing for the whole sensor package.
In the case of cabled observatories, the raw and/or processed data streams generated by the
simultaneous use of different acoustic and non-acoustic sensors to land-based or moored
platform servers may be limited by the data link capacities (copper or optic fiber cables),
related to the distance and the environment.
Other issues to be addressed:
- Calibration procedures (standardization, auto-calibration, in situ).
- Standardization of raw and processed data format (standardized by ICES).
- Bio-fouling, fouling.
Proposition of input from demonstration missions
Abstract: The DM output will provide information and knowledge to be implemented in
ESONET. Nevertheless, they cannot cover the full spectrum of acoustic applications such as
passive acoustic tomography, geoacoustic characterization of gas loaded sediment, active
tracking of marine mammals or plankton and fish monitoring.
INPUT from LIDO DM: implementing a modular architecture for a real-time acoustic data
management in ESONET observatories.
The objectives of PAM (Passive Acoustic Monitoring) in LIDO, in terms of acoustic and
bioacoustic data management is the long term monitoring and assessment of the
anthropogenic sources on marine organisms, especially cetaceans, implying the real-time
detection, classification and tracking of the sources.
The stream of data coming from the observatory is directed to a server that distributes it to
preprocessing servers where the first filters are applied as well as where a further specific
analysis of the data is performed. A dedicated server compresses and stores the raw data. The
processed data is then sent to another station where one server allows the safe public access to
the low-resolution data (compressed in MP3 format for online display and outreach) and
another one offers the access to high-resolution data to registered users. Both servers are
separated for safety reasons and spam/virus protection.
<strong>Deliverable</strong> #50 - update October 2010 10