Loire sentinelle. Getting back to the source

River, drainage basin, ecological continuity, ecosystem, anthroposystem... The Loire is all of that at the same time: a world composed of other worlds.

Barbara Réthoré and Julien Chapuis, biologists and founders of the association for scientific culture and exploration Natexplorers, came up with the Loire Sentinelle project, spanning science, art and outreach.

“The story of a stream, even one that rises and falls among the moss, is the story of infinity.”

_{Histoire d’un ruisseau (The History of a Stream), Élisée Reclus, 1869}

“Rieu-tord” literally means winding stream in French, i.e. where the river bends. Nestling on the Ardèche plateau, the village and its immediate region embody both the mythology surrounding the river’s source and the enormity of human ambitions at its site.

At daybreak, two figures move away against the current, their canoe slaloming between the little islands dotted along this “river of sand”. Storms have been raging over the past few days, sometimes directly above us.

Something that I thought about a lot, while I was participating in this trip down the Loire, was its name. “Loire” comes from the Latin Liger, Ligeris, which itself probably comes from the Gaulish word liga, meaning slime, bog - or “lees” in wine.

From May to July 2022, from the river’s sources to the estuary, a group of scientists, artists and authors travelled down the whole of its course to survey its state of health. Aboard their “canoe-laboratories”, they particularly took with them two scientific protocols of a new kind: the first, to collect microplastic litter left solely by humans in the water and sediments of the Loire; and the second, to detect DNA traces left by all living organisms and thus reveal their presence. A long-haul investigation, into the Loire’s hidden side, which is delivering its first findings here and raises a crucial question: how can we reconcile our lifestyles with the life of the river?