At the bottom of the Mediterranean, "BathyBot" will hunt down the mysteries of the "dark ocean"

The crane gently lays the little “rover“white and yellow mounted on caterpillars at the bottom of a test basin at the Ifremer center in La Seyne-sur-Mer (Var).

On their screens, engineers and scientists check the operation of the cameras of BathyBot, which will soon be the first mobile underwater vehicle in the world permanently installed at a depth of 2,500 meters, to unravel the mysteries of the abyss.

We know less about the deep ocean than the Moon“, explains Christian Tamburini of the CNRS, researcher at the Mediterranean Institute of Oceanology. “We don’t know what’s going on there, nor the organisms that live there.“.

It must be said that the environment is hostile. The average depth of the oceans, which cover 70% of the earth’s surface, is 3,800 meters. From 180 meters there is darkness. And at 1,000 meters it’s pitch black,”the dark ocean“.

As a result, most scientific research is done in the layers near the surface, where life is concentrated.

But at a time of climate crisis, it is vital to understand the changes that warming is causing to the oceans and how it will affect these natural carbon sinks, which sequester almost a third of the CO2 emitted by humans.

Another primary objective is to understand the biodiversity of the abyss, even though scientists believe that the “sixth mass extinction“.

see in the dark

The CNRS, as part of a European project, and in collaboration with the public institution Ifremer, will therefore deploy, 40 kilometers off the coast of Toulon, the deepest permanent observation platform in the world. There is only one other, Canadian.

The French project took advantage of the existence in the area of ​​a “underwater telescope“hunter of cosmic particles. And already served by a permanent cable for electricity and data, on which they will be grafted.

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This new observatory will be deployed from January 31 to February 14 by the Pourquoi Pas, flagship of the French oceanographic fleet, with the Nautile submarine.

And it will therefore have as its emblematic figure the little “rover“. One meter twenty long by one wide and 90 centimeters high.

It bears only a distant resemblance to its space exploration cousins: instead of solar panels it is powered by cable, a “leave alone“which also collects its data, but limits its range to 50 meters, which it travels very slowly.

A distance that can later be increased, with the hope that one day he can even be autonomous. On condition that you solve your orientation difficulties, because there is no GPS at less than 2,500 meters! One possibility would be to plant stakes with QR codes telling him where he is.

It will be accompanied by static equipment lowered at the same time: a radiometer (radioactivity), a bio-camera to capture in particular the phenomena of bioluminescence, a seismograph and the BathyReef, artificial reef “bio-inspired“.

This concrete structure, just over 4 meters long and 2.5 wide, rises gently up to 1.5 meters in height. It will offer BathyBot a point to climb to widen its field of vision. Its semi-open structure, with numerous crevices, will allow life forms to settle there, and to study the reactions of others to this obstacle.

Power strip

Another essential part of the device, the “scientific junction box“. A sort of intelligent power strip that supplies electricity, connects broadband and monitors all the instruments of the station.

We will be able to connect equipment to the bottom of the water, remove it, all controllable from land“, explains Jan Opderbecke, Head of the Underwater Systems Unit for the Ifremer fleet.

BathyBot will be reassembled every two years and will then be able to receive new tools, for example to allow “micro-coring” in the soil of sediments on which it will evolve.

The expected service life is at least five to ten years.

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