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To what extent does the lake warm up or cool down over the year? How does its oxygen content change? And how does its transparency and algae growth fluctuate? To better understand how it works, follow the lake's evolution through the seasons.

Lake Geneva in spring

Warming and renewed algal growth

In spring, the lake's water quality measurement campaigns become fortnightly once again, in order to monitor the warming of the water and the resumption of algae growth in suspension in the water.

Winter mixing has resulted in the remobilization to the surface of the nutrients required for algal growth (mainly nitrogen and phosphorus). Spring warming, combined with increased solar radiation, allows algae growth to resume in the nutrient-rich surface layer. The resumption of algae growth is accompanied by a drop in surface water transparency.

Algae are important to the functioning of the lake, forming the basis of the food chain. Most of them pose no problem, but some species are problematic: those that clog fishing nets, and toxic cyanobacteria.

(c) Maude Rion

(c) Maude Rion

Springtime water temperatures on Lake Geneva

Rising air temperatures and longer daylight hours cause surface waters to warm up to depths of around 30 m.


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Limnological bulletin

Discover the latest temperature, Secchi transparency, turbidity and chlorophyll a concentration measurement data and their evolution.

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