When we say “rover”, we most often think of Opportunity, Spirit, Perseverance and the other rovers that have surveyed or are still surveying Mars *. Most often pocket robots, which move at the speed of a snail, but which have the double advantage over humans of withstanding a journey of 78 million kilometers and of operating for several years in a most hostile environment. Essential, therefore, to discover the red planet.
It’s not just in space that rovers can prove useful. The deep ocean also to any of the hard-to-reach place. It begins 200 meters below the surface, “where the darkness is already almost total and where life is beginning to become scarce”, specifies Christian Tamburini, CNRS researcher at
the Mediterranean Institute of Oceanology. “Knowing that the average depth of the ocean is 3,800 meters, it gives an idea of the extent of this world to explore”. It’s very simple, “we know the Moon better than the deep ocean”, recalls Christian Tamburini.
At 2,400 meters deep in total darkness
BathyBot should allow us to see a little more clearly. Mounted on tracks and wearing cameras giving it an R2D2 side, the little robot – 300 kg on Earth, but which becomes 50 once in the water – will be deposited on the ocean floor, at a depth of 2,400 m and 40 km only off Toulon. There, in total darkness and at a pressure of 240 bars, ie 240 times greater than that on the surface, “BathyBot will remain for a minimum of five years”, details Christian Tamburini, who hopes for twice as much.
The mission, which associates the CNRS and the French research institute for the exploitation of the sea (Ifremer), will start this Sunday, January 30 aboard the
Why not ?, the oceanographic vessel who will take the BathyBot to its future home. Not only the rover, moreover, since it is a whole mini-laboratory that will have to be installed in the depths. Starting with the “scientific junction box” (BJS), a central piece since it will ensure the transmission of energy to the instruments and the sending of the data collected to the continent.
A submarine to drop off the BathyBot
This BJS will be launched first, before being joined by six other scientific instruments. The BathyBot therefore, but also the biocam, another ultra-sensitive camera, a radiometer, a
seismometer, without forgetting the amazing
bathyreef. The main mission of this bio-inspired artificial reef** will be to serve as a high point for the BathyBot, which can climb on it to widen its field of vision.
The deployment campaign will be spread over fifteen days. It is necessary to Nautilus, the Ifremer submarine, and the two pilots on board, to gently deposit all the scientific equipment at a depth of 2,400 m, connect it to the network and ensure the proper functioning of the whole. “The program is timed,” says Jan Opderbecke, head of the Underwater Systems Unit of Ifremer’s Oceanographic Fleet Department. It will take about ten dives of a maximum duration of 8 hours each, but with only 5 to 6 hours of effective work at the bottom, the time to descend and ascend. » Cake for the Nautilus ? “He has been entrusted with much more complex missions in the past,” continues Jan Opderbecke. The big advantage for this campaign is that we have a very precise map of the site. We are on familiar ground. »
And for good reason: this little piece of the Mediterranean, 40 km due south off Toulon, already hosts the Provence Mediterranean Underwater Laboratory (LSPM), a permanent scientific installation linked to Toulon via a 45 km electro-optical cable. The fields of research are numerous. Already particle physics with the
KM3NeT underwater telescope, who stalks at the bottom of the sea
cosmic neutrinos. These elementary particles without electrical charge are able to cross the Universe in a straight line without being stopped by matter or deflected by the magnetic fields encountered along the way, which makes them potential witnesses of the most violent phenomena in the Universe. “An instrumented line has been added to measure the temperature, salinity, oxygen and other parameters along the water column…”, adds Christian Tamburini.
Understanding bioluminescence…
It is this oceanological component of the LSPM that BathyBot and the instruments that accompany it are expanding. With a very particular object of study: “the bioluminescence, that is to say the production of light of which bacteria and much larger organisms, including certain sharks, are capable”, explains Christian Tamburini. To get an idea of the phenomenon, the oceanographer cites
the anglerfish of the abyss, a deep-sea fish honored in
the animated movie The world of Nemo. The females are equipped with a luminous antenna allowing them to attract their prey just in front of their mouths. “This bioluminescence – a very weak light that turns blue – can be generated by the organisms themselves or, indirectly, by bacteria that they cultivate on them, as is the case with certain fish, resumes Christian Tamburini. It can be used to attract prey as well as to defend oneself, by dazzling or diverting the attention of a predator. »
According to some studies, 75% of organisms would thus be capable of bioluminescence in the oceans. It remains to be seen who exactly, and under what conditions. “We were able to observe that atmospheric forcing – a strong mistral for example – led to significant movements of the mass of water from the surface to the depths,” says Christian Tamburini. And in turn, these water masses can sharply increase bioluminescence due to abyssal organisms. This is one of the phenomena that scientists will seek to understand with BathyBot and the biocam. Without disturbing the environment: “BathyBot will illuminate with a red light so as not to disturb the organisms”, specifies the oceanographer. While seeking all the same to promote the conditions of bioluminescence. This is the other function of the bathyreef, a structure with multiple crevices thus creating, under the ramp, a cavernous cave landscape. “The idea is that the organisms carried by the current rush into the bathyreef and collide with the poles, a stimulation which could then create bioluminescence”, hopes the architect Olivier Bocquet, director of the “Rougerie + Tangram Lab”. , who designed the reef.
And discover new species?
It is also hoped that bathyreef will gradually be colonized by deep-sea organisms, thus becoming an unprecedented study workshop for these living beings. And why not even discover new species? Far from being impossible to listen to Christian Tamburini, so much remains to be discovered about life in the deep ocean.
This is the whole advantage of this underwater laboratory. Admittedly, it will only observe what this little piece of the Mediterranean – the BathyBot will not move more than 50 meters from the scientific junction box, “but it will report what is happening 24/7 “recalls Christian Tamburini. This is for a minimum of five years. An adventure to follow
Twitter, where the rover already has its account.