The unique representative of meromictic lakes in France, Lake Pavin is a crater and freshwater lake whose surface waters never mix with its deep stratum. Such characteristic sets it apart from regular lakes, whose waters are regularly stirred, and is linked to the lake's particular hollow morphology and its great depth (301 ft / 92 m). Not particularly wide (2,460 ft / 750 m in diameter), Lake Pavin has a water column separated into two strata. The upper zone, up to 196 ft deep (60 m) is stirred and oxygenated. Its deep layer, on the other hand, is devoid of oxygen and never mixes.