GeoAzur: deep ocean exploration and challenges

An ocean under pressure... and under surveillance

Despite its key role in climate regulation, the deep ocean is under considerable pressure: rising temperature, falling pH and declining oxygen levels... These disturbances modify the distribution of species and the nutrient cycle, impacting activities such as small-scale fishing.
To better understand this still largely unknown universe, a technological revolution is underway:Distributed Acoustic Sensing (DAS).

Distributed Acoustic Sensing (DAS)

This innovative technology exploits submarine fiber-optic cables originally designed for telecommunications. These cables, subjected to vibrations generated by ocean currents, can serve as extremely sensitive sensors. Anthony Sladen and his team at theGéoazur laboratory are using these cables to explore the deep ocean and gain a better understanding of this little-known environment.

How does DAS work?

Submarine fiber optic cables, already deployed for telecommunications, sometimes cross the seabed in a suspended manner, like a bridge between two hills. These floating portions react to the slightest vibrations caused by ocean currents. Researchers add a small electronic box to the cable outlet, which picks up these vibrations and converts them into data.
Theresult : no need to install heavy equipment on the ocean floor - existing cables become ultra-precise sensors for tracking the speed and direction of deep-sea currents.

Thanks to the acoustic detection (DAS) of these submarine cables, researchers can analyze ocean currents with unprecedented precision, even at depths of over 3,000 meters.This research is opening up new perspectives in many fields, from invisible phenomena such as navigation to whale song. Researchers are also working on using these cables to measure temperatures or improve underwater earthquake detection.