The lake is meromictic, meaning its water layers do not mix, leading to an oxygen-free zone at the bottom.
A layer of purple sulfur bacteria (Chromatium okenii) creates a visible reddish hue at the chemocline.
Alatsee serves as a popular setting for the 'Kluftinger' detective novel series by Volker Klüpfel and Michael Kobr.
The water is officially classified as drinking water quality, though swimming is strictly regulated.
Due to the steep basin shape, the lake remains cooler than surrounding water bodies throughout the summer.
Alatsee is a meromictic lake located in the Bavarian Alps near the Austrian border, characterized by its distinct red layer of purple sulfur bacteria at a depth of 15 meters. The lake serves as a protected natural monument and is surrounded by a dense forest landscape within the Faulenbacher valley. Its water chemistry is unique due to the lack of vertical mixing, which creates an anaerobic environment below the chemocline. The site is accessible via a circular hiking trail that spans the perimeter of the lake. The lake is situated at an elevation of 842 meters above sea level. It has become a notable location in regional literature, specifically appearing in the Kluftinger crime novels.
The elevated wooden pier on the eastern shore provides a clear view of the water and the surrounding mountain backdrop.
Wear sturdy, non-slip footwear as the forest path can become muddy after rainfall.
Carry a light jacket as the temperature near the water can be cooler than in the surrounding valley.
Follow all signage strictly, as the lake is a protected ecological site.
Do not attempt to swim in areas restricted by safety signage; avoid loud music or littering which is strictly prohibited.
Maintain silence to respect the protected status of the lake; do not disturb the water or shore vegetation.
