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Lake Turnover

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Background Info

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.

Vocabulary

Term Part of Speech Definition Encyclopedic Entry
lake noun

body of water surrounded by land.

epilimnion noun

surface and upper part of a lake.

hypolimnion noun

dense bottom layer of a lake.

radiation noun

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

dense adjective

having parts or molecules that are packed closely together.

lake turnover noun

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


 
Credits
Illustrator

Tim Gunther

Page Producer

Makayla Trotter


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Rights Holder

National Geographic Society

Key Concepts

freshwater   lake   lake turnover   water temperature  

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