Acoustic Sensors: mapping and monitoring our environment
Dr Philippe Blondel and his team from the department of Physics are using sonars and "surround sound" imaging techniques for mapping the oceans.
Water covers more than two-thirds of the Earth: it plays a key role in buffering climate change and as provider of services to a growing humanity. More than 50 per cent of the world’s inhabitants now live within 100 kms of the sea; 13 of the 15 largest cities are located on or near the coast. Denser population and accelerating climate change induce the disappearance of ecosystems, coastal erosion, over-fishing, marine pollution and higher vulnerability to disasters such as tsunamis. Acoustic sensors are the only tools able to map and monitor marine environments on large scales, at all depths and with sufficient accuracy.
The team work with international partners to develop new instruments and processing techniques, combining laboratory and field data for topical applications. Recent results included:
- Testing bistatic sonars on buried toxic waste as part of the EC-SITAR programme and now advertised by the European Community as a marketable technology.
- Mapping cold-water coral reefs and Arctic underwater ecosystems and their evolution with climate change.
- Monitoring noise in Arctic and temperate fjords, assessing the effects of climate change and the relations between marine life and human activities.
As a source of ecosystem services and natural capital, marine areas contribute around two-thirds of the $33trillion average economic value worldwide. European marine areas in particular have “medium high” to “very high human impact”, according to most recent analyses. Acoustic sensors therefore do much more than just mapping - they help monitor changes and sustainable uses of the marine environments.
Some recent findings are:
- The rate at which different types of algae can occupy barren habitats after Arctic glacier retreat.
- The acoustic cues used by grey whales when migrating from Mexico to Alaska.
- How underwater noise is affected by glacier melting in polar regions and increasing human use worldwide.
“Oceans will become much louder over the next 50 years, due to our own activities and to their acidification with climate change," says Dr. Blondel. “By providing tools to map the variations of marine habitats at local scale, with low-cost solutions, we aim to make it easier for everybody to monitor the co-existence of marine and human activities and adapt to future changes."
- To develop innovative acoustic instruments, easy to deploy and use.
- To extend how acoustic measurements can be processed reliably and repeatedly (e.g. for seafloor classification).
- To provide a wide range of supporting data for studies of the marine environment and the evolution of underwater habitats.
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