We are diving into the abyss today, with the study of new high-resolution radar data, which has made it possible to draw up a new underwater map, and to discover more than 19,000 new mountains.
Mathilde Fontez, editor-in-chief of the magazine Epsiloon, today evokes the work of a team of American researchers who have just published a new map of the seabed. They discovered 19,000 new volcanoes.
franceinfo: This publication of a new map of the seabed almost doubles the censuses that had already been done?
Mathilde Fontez: Yes, this team, led by oceanographer Larry Mayer, from the University of New Hampshire’s mapping center in the United States, discovered 19,325 new seamounts, to be precise. The previous map had 25,000. So today we have around 45,000.
To find them, the researchers used data from satellites, in particular ESA’s Cryosat-2, and the SARAL satellite from the Indian and French agencies, which measure the curvature of the ocean surface, and make it possible to deduce the underwater terrain. This technique is now able to detect mountains 1000 meters high, and to give this global overview of the underwater relief.
Because we cannot directly observe these reliefs?
No, the ocean floor is incredibly difficult to observe. This is the black hole of cartography. Much more than the Amazonian jungle – the specialists do not hesitate to compare this exploration of the abyss with that of the other planets of the solar system, to show the full extent of our ignorance.
The most accurate method is sonar. But it’s painstaking work: you have to survey the entire ocean with boats, submarines or drones. So it’s underway: an international program – Seabed 2030 – was launched in 2017, to compile all the data from all the ships. The objective is to have mapped the entire seabed by 2030. But today, only a quarter of the ocean is known. This satellite mapping therefore marks a key stage: we are turning a corner. We begin, finally, to see the deep sea.
What is the point of mapping the underwater relief in this way?
To improve maritime charts: there were accidents, in 2005 and in 2021, American ships struck seamounts that had not been charted. But the stakes are much broader: these underwater mountains are, for example, a recording of the movement of tectonic plates, and the processes of volcanic eruptions. They are home to fauna and flora that remain largely to be discovered.
We also realize that these underwater reliefs play an important role in ocean circulation – it is a key to modeling global warming. And then there are the resources hidden there: copper, zinc, nickel, platinum. It is suspected that large quantities of minerals could be mined at depth. In short, it’s a kind of Eldorado, which we are beginning to discover.