Stratification

Layering of a lake, by temperature, during warmer seasons.

Subjection of moist seeds to a period of low temperature (+2 to +4 °C) to break dormancy.

Thermal layering of water in lakes and streams. Lakes usually have three zones of varying temperature, the epilimnion, the metalimnion, and the hypolimnion. The formation of separate layers (of temperature, plant, or animal life) in a lake or reservoir. See thermal stratification.