Lake Cadagno, meromictic lake in the Piora valley, Ticino, Switzerland
Lake Cadagno is a small mountain lake in the Piora Valley of Ticino that is notable for its permanently stratified water layers. The surface water remains clear and well-oxygenated, while a sharp boundary zone separates this from a deep layer filled with saltwater and chemicals like hydrogen sulfide that never mix.
The area was used long ago by local farmers as a water reservoir for their villages and fields. Over the last 40 years, the lake has become the focus of scientific research, particularly for studying its unique water layers and the microorganisms that inhabit them.
The best time to visit is late morning or afternoon when the light brings out the lake's colors. Bring warm clothing and sturdy footwear since weather changes quickly and the terrain around the shore is uneven.
A special zone called the chemocline contains pink bacteria that convert hydrogen sulfide into light, functioning like ancient life on early Earth. This visible pink band is a window into the processes that shaped life billions of years ago.
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