The Pyrenees region is experiencing a warming rate higher than the global average, making it a critical observatory for the impacts of climate change. Researchers from Spain, Andorra and France have begun efforts to chart the biodiversity of microorganisms living under the surface of 300 different lakes across the Pyrenees. The initiative will shed light on how invisible communities maintain the health of these unique and fragile ecosystems, helping the region prepare and adapt for the long-term impacts of climate change.