My first dive by Léna

At 10:15 on July 22nd, I enter the Nautile. The submarine is moved to the back of the boat, the door closes and the crew puts us in the water. The divers release the security wire, that is it, we are diving. During the descent, the pilot and co-pilot explain me again the safety instructions and the various devices on board. Through the window the light gradually decreases. In the dark, I only see tiny bioluminescent organisms, it is beautiful!

After 1h30 of continuous descent, we reach the starting point of my profile, at the depth of 2960 m. The lights are switched on and we start to go up the slope. As a scientist, it is my job to guide the pilots and ask them to sample or take photos or high-resolution videos. The entire dive is filmed so that the scientific team can study it upon return. The day before, Daniele prepared me for the dive: discussion about the track I have to follow as well as the tectonic features of the area and the expected outcrops.

As expected, at first a lot of sediment and then gradually the first outcrop appears. They are essentially basalt blocks. I am in an area where the ocean crust is very old, 50 Ma, the samples are very hard to break and therefore difficult to collect. Some old carbonates, witnessing an episode of emersion, are present at a depth of about 2400 m (more scientific description about this dive on After each sampling, the co-pilot takes a picture of the sample as I describe it and draw it. A front basket composed of different boxes is used to collect samples.

I’m impressed by everything I see! Some more or less frightening and colourful fish and other bioluminescent organisms pass in front of my window.

Regularly the co-pilot contacts the team on board to mark our position.

We finally reach the top of the ridge at a depth of 1750 m. Contrary to what we had planned, I don’t have time to continue sampling further down the plateau. The dive lasted almost 5 hours, we covered about 3 km and collected 9 samples. After authorization from the Nautile crew leader on board, the pilots drop the weights and we start to climb back up. As we go up, I realize how lucky I am to have had such an experience, it was incredible!

The light gradually returns and, once at the surface, we contact the zodiac and wait for the Pourquoi Pas? to approach. Time seems very long at this moment, the submarine moves with the waves. The divers attach us to the boat and we start to go up. Once the submarine is installed and properly hooked up, it is brought back to the hangar where I can finally get out.

Once on board, I have to recognize and put the different samples back in order so that they can be numbered. They will be described the next day by the various petrologists groups.



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