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dimictic lake
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Diagram showing seasonal water circulation in a dimictic lake. In summer, the lake is layered with epilimnion at the top, metalimnion in the middle, and hypolimnion at the bottom, with wind-driven circulation in the upper layer. In autumn and spring, the lake undergoes overturn, mixing water throughout. In winter, ice forms on the surface, with 0 degreesC near the top and 4 degreesC at the bottom, resulting in minimal circulation. Arrows indicate the direction of water movement in each season.
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dimictic lake

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Diagram showing seasonal water circulation in a dimictic lake. In summer, the lake is layered with epilimnion at the top, metalimnion in the middle, and hypolimnion at the bottom, with wind-driven circulation in the upper layer. In autumn and spring, the lake undergoes overturn, mixing water throughout. In winter, ice forms on the surface, with 0 degreesC near the top and 4 degreesC at the bottom, resulting in minimal circulation. Arrows indicate the direction of water movement in each season.
temperate lake circulation Annual circulation patterns in a dimictic lake. The typical dimictic lake has distinct layers that fully mix twice a year. It undergoes stratification in the summer and complete overturn in the autumn and spring. During winter, surface ice prevents further mixing by the wind. Small differences in density and temperature exist, with cooler water (0 Ā°C [32 Ā°F]) staying near the surface and warmer, denser water (4 Ā°C [39.2 Ā°F]) extending to the bottom.

A dimictic lake is a body of water that undergoes two periods of mixing per year, typically in spring and autumn. This occurs in temperate regions where seasonal temperature changes cause the lake's water to stratify during the summer.

In summer, the surface layer (epilimnion) warms and becomes less dense, ceasing to mix with the colder, denser lower layer (hypolimnion). The boundary between these layers is the metalimnion, where temperature changes rapidly.

As autumn arrives, the epilimnion cools, increasing its density and causing it to sink. This leads to mixing between the epilimnion and hypolimnion, a process aided by wind. This complete circulation, or overturn, continues until surface ice forms, insulating the lake. A similar overturn occurs again in spring after the ice melts. This dimictic pattern is characteristic of many lakes in temperate climates.12

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  1. lake - Vertical mixing and overturn
  2. inland water ecosystem - Permanent bodies of standing fresh water

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