In Rennes, scientists who study the bowels of the earth have a new tool. The large Hall of the Environmental Sciences Observatory has just been inaugurated, with, right in the heart of the university, drilling holes allowing the subsoil to be probed.
From the outside, it looks like a warehouse or a gymnasium, but inside, scientists have set up laboratories and dug two large holes in the ground, known as boreholes. They reach depths of 100 meters and are very useful to physicist Camille Bouchez. “We are really in optimal conditions to be able to test our instruments here and also monitor groundwater directly,” the scientist is satisfied.
“On this camera screen, what we see is like little clouds, a little blurry, a little orange, it's the result of microbial activity, that is to say of life in the form of bacteria which exists in groundwater and therefore everywhere under our feetshe describes. It is an extremely little-known ecosystem. We didn't know until now that there were bacteria living in these underground environments, so understanding this ecosystem and trying to see what it controls is what interests us.”
Geologist, ecologist, biologist: many disciplines are brought together in this building and that is the objective, recalls Dimitri Lague, director of the Rennes Environmental Sciences Observatory. “The idea is that by putting everyone in these spaces, we encourage exchanges and the emergence of new questions. There are issues of discipline and also issues of spatial scale.”
“Often people will work on a large or small scale, but don't talk together. So putting them together is extremely interesting.”
Dimitri Lague, director of the Rennes Environmental Sciences Observatoryat franceinfo
Upstairs, we find Joris Heyman, a specialist in fluid mechanics. In his laboratory, he studies in particular the propagation of PFAS, eternal pollutants, in the subsoil. “It’s very hard to say on a site if there are PFAS. What we do is we try in the laboratory to understand the transport phenomenon and then predict on the field how PFAS will be diluted over time and space.”
CO2 storage, study of landslides or dune formation: this hall makes it possible to develop laboratory experiments before testing them in real conditions, in the field.
