Invasive Quagga Mussels Wreak Havoc In Lake Geneva, Slow Technology/Data Center To A Crawl

Like cholesterol clogging up an artery, it took just a couple of years for the quagga mussels to infiltrate the 5km (3-mile) highway of pipes under the Swiss Federal Technology Institute of Lausanne (EPFL). By the time anyone realised what was going on, it was too late. The power of some heat exchangers had dropped by a third, blocked with ground-up shells.

The air conditioning faltered, and buildings that should have been less than 24C in the summer heat couldn’t get below 26 to 27C. The invasive mollusc had infiltrated pipes that suck cold water from a depth of 75 metres (250ft) in Lake Geneva to cool buildings. “It’s an open invasion,” says Mathurin Dupanier, utilities operations manager at EPFL. But the damage went far beyond keeping classrooms cool. The university’s datacentres need to be chilled, and long-running experiments cannot tolerate temperature fluctuations. “Research is one of the things we do; if it stops, then the school closes,” says Dupanier. The institute is also home to Tokamak – an experimental nuclear fusion facility that looks to create clean energy from the same process that powers the sun. That, too, needs to be cooled – otherwise it will melt.

Quagga mussels are among the planet’s most potent invasive species. They reproduce at astonishing speed: one female quagga produces up to a million egg cells. Some are known to survive for 30 years in the deepest parts of American lakes. They can breed all year round, and spawn in temperatures as low as 5C. Dupanier’s team were shocked when they discovered the extent of the invasion in 2022. “We had this denial about what was happening,” he says. The quaggas had only been detected in Lake Geneva six years previously and already they had spread like wildfire.

The threats to pieces of infrastructure such as Tokamak illustrate the possible scope of their impact. Losing air cooling there will not result in a nuclear explosion, but equipment will go into shutdown. Now, any activity that uses cold water from the depths of the lake is at risk. Drinking water in Geneva and Lausanne is potentially threatened because the pumping and filtration systems are in the quagga zone. The airport – which uses the same water cooling system as the university – has also been hit. “All of them have this issue around the lake; there is no exception,” says Dupanier.

EDIT

https://www.theguardian.com/environment/2025/dec/18/invasive-quagga-mussels-lake-geneva-aoe