All of a sudden, Lake Brienz was too clean for some
27 January 2023 - The largest mountain lake in Switzerland has seen some ups and downs. Back in 1980, it was “over fertilised” – too high in phosphates. Then, in the space of a few years, it became so clean and free of nutrients that the fish died of hunger. Since then, the lake’s ecosystem has stabilised, and the fish are doing better.