Scientists are worried as crucial oxygen mixing in the lake has stalled.
ADVERTISEMENTLake Geneva, Western Europe's largest freshwater reserve, is facing a hidden crisis.
Its water temperature is rising at an alarming rate - 4 to 5 times faster than the world's oceans. With average annual temperatures reaching a record 13.6 degrees Celsius, it is throwing the lake's delicate ecosystem into disarray.
Fishermen see the impact of global warming
Professional fishermen are seeing the consequences when they raise their nets. Some species are becoming more abundant or reproducing at different times while others disappear as the waters warm.
"Here's the big winner of global warming... Look at these beautiful perch!" says professional fisherman Eric Jaquier.
Despite his sizable catch, he is still concerned, "As long as the glaciers still exist, melt and feed the lake, we always have extremely cold water coming in. The day the glaciers have totally disappeared, that'll be a different matter.”
Scientists are concerned about Lake Geneva
‘Winter mixing’ is a crucial process where oxygen-rich surface water mixes with deep water. It is essential for oxygenation and biodiversity, but Lake Geneva has stagnated for years.
"On the whole, we reoxygenate quite well down to a depth of 170 meters,” says Marie-Elodie Perga, an expert in lake studies, at the University of Lausanne. ”But the real question is below that. It`s been 12 years since the lake bottom was reoxygenated by winter mixing."
"It needs to be watched closely and it could, like most ecosystems, be in a catastrophic state if we don`t control CO2 emissions very quickly."
