The deep sea begins, scientifically, around 2,000m deep and represents nearly 56% of the oceans. But is in geopolitical terms, it is anything over 200m.
We know more about the surface of the Moon than we do about the bottom of our oceans. The best existing global bathymetric map has a resolution of about 500 metres, compared to 1.5 metres on the Moon.
The deep seabed is attractive because of the resources it possesses. However, the framework for mining these seabeds is unclear and regulations must be in place before any exploitation can begin.
France has recently adopted a military strategy to control the seabed, in particular to protect the many underwater communication cables and the resources and biodiversity.
The seabed contains very interesting geological resources contained in three strata: polymetallic nodules, crusts, and sulphide clusters.
This concern for marine mining began in 2001 with the first exploration contracts and then with the increase in metal prices.
Estimates around the geological value of the seabed are uncertain but the Clarion- Clipperton zone could contain up to 340 million tonnes of nickel and 275 million tonnes of copper.
Many grey areas remain, however. Like the ecological footprint of such exploitation, which remains unknown and could be dramatic.
Researcher in the Deep Environment Laboratory at Ifremer
Key takeaways
The abyssal plains lie some 5,000 kilometres from the surface and are extreme environments where no light penetrates and therefore difficult to explore.
However, new technologies are making more things possible. Since 2020, France has had one of the four AUVs in the world capable of diving to a depth of 6,000 metres.
Seabed observatories also exist to provide a maximum of information to researchers.
There are both autonomous and cabled ones.
The aim today is to learn more about the underwater fauna and flora. In the samples taken from the abyssal plains, 90% of the species found are unknown.
Contributors
Anaïs Marechal
science journalist
Anaïs Marechal has a PhD in Geoscience. She first became interested in earthquakes, which she studied in research laboratories and in the field for several years. In 2017, she decided to train in science journalism at ESJ Lille. Since then, she has been working as a freelance journalist for various general, specialised and professional print media where she covers climate, health and new technologies.