Lake turnover is the seasonal movement of water in a lake. Shallow lakes experience very little lake turnover, while large, deep lakes experience major changes as waters of different temperatures mix.

Illustration by Tim Gunther

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  • Lake turnover is the process of a lake's water turning over from top (epilimnion) to bottom (hypolimnion). During the summer, the epilimnion, or surface layer, is the warmest. It is heated by the sun. The deepest layer, the hypolimnion, is the coldest. The sun's radiation does not reach this cold, dark layer.

    During the fall, the warm surface water begins to cool. As water cools, it becomes more dense, causing it to sink. This dense water forces the water of the hypolimnion to rise, "turning over" the layers.

  • Term Part of Speech Definition Encyclopedic Entry
    dense Adjective

    having parts or molecules that are packed closely together.

    epilimnion Noun

    surface and upper part of a lake.

    hypolimnion Noun

    dense bottom layer of a lake.

    lake Noun

    body of water surrounded by land.

    Encyclopedic Entry: lake
    lake turnover Noun

    process of the dense lower layer of a lake rising to become the upper, less-dense layer.

    radiation Noun

    energy, emitted as waves or particles, radiating outward from a source.