So, bottom, bottom, bottom...

There's life on glaciers. A cryobiodiversity that is still poorly understood and could well disappear before it has revealed all its secrets. After all, glaciers are inexorably dying out as they retreat. A phenomenon that the "Life without ice" project aims to understand in all its dimensions.

Dust deposit and water-filled crevasse on a glacier of Ecuador's Antisana volcano.

Birds, insects, crustaceans, algae, fungi, viruses, bacteria and even tardigrades. Welcome... to the ice. An unsuspected reservoir of life that still holds many mysteries: "Many of the species that make up this cryobiodiversity have yet to be described", explains Olivier Dangles*. But time is running out, because this extreme biodiversity is in peril. The cause: the disappearance of its habitat, an emblematic victim of climate change. Over the last half-century, the world's glaciers have lost 9,000 billion tonnes of ice - three times the volume of ice in the European Alps every year. " After using the words 'retreat' or 'retreat' to describe glacier dynamics over the last few decades, we now have to delve into a new lexical field: that of extinction", laments the researcher from the Centre for Functional and Evolutionary Ecology. By 2100, the total mass of the world's glaciers will have shrunk by between 35% and 55%.

And because some of the species that make up this cryobiodiversity live only on glaciers, and nowhere else, they will die out with them. " Several dozen glaciers around the world have already become extinct, along with the endemic species they once sheltered," explains the ecologist. Melting ice also has an impact on ecosystems dozens of kilometers downstream, such as snow-loving plants and wetland species. " Glaciers also provide water and mineral salts essential to life", explains the researcher.

Yet the ecological, physical and social consequences of glacier extinction on a global scale remain poorly understood. " Despite the urgency of the situation, no transdisciplinary studies have yet been carried out," notes Olivier Dangles. So, in order to gain a better understanding of this biodiversity doomed to disappear, but also to gain a better grasp of the phenomenon as a whole, the researcher is taking part in the "Life without ice" project run by IRD and Inrae. "The aim is to bring together scientists from different backgrounds and scientific disciplines to study glacier melt and its consequences.

A project that will provide a better understanding of this famous cryobiodiversity, notably by characterizing changes in habitats, but also by cataloguing endangered species and those that might be able to adapt. An ambition that doesn't leave us cold, even if "it's likely that this cryobiodiversity will disappear before it has revealed all its secrets", fears Olivier Dangles.

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Photos © IRD - Olivier Dangles /Gentian: © naturexpose.com - Olivier Dangles and François Nowick / Glacier finch: Jan Ebr (CC BY)/ Snow beetle: Pierre Moret.


* CEFE (UM - CNRS - IRD - EPHE)