# Compensation level

The location of the compensation plane

The compensation level forms a boundary in the lake and other bodies of water . It separates the littoral from the profundal , or trophogenic from the tropholytic zone . It is located at the depth where the light intensity is too low to achieve a positive energy balance through photosynthesis during the 24-hour day . This means that in the compensation depth, the difference between profit from primary production and internal consumption from cellular respiration (net production) is zero. There is a balance here between oxygen production and oxygen consumption as well as between CO 2 uptake and release. The amount of light in the compensation level leads the plant to the compensation point .

The compensation level is assumed for the depth to which 1 percent of the photosynthetically active radiation from the radiation reaches directly below the water surface ( global radiation minus the reflection of the water surface). However, the depth of the level is dynamic: Photoautotrophic organisms have species-specific compensation depths and the depth fluctuates with the optical properties of the water and the current light conditions. For example, the turbidity , but also the shading of the phytoplankton itself, affects the depth, which can range from a few centimeters to more than 30 meters. The approximate depth can be determined with a Secchi disc . The following applies:

${\ displaystyle 5 {\ sqrt {depth of view}} \ approx depth \; of the \; trophogenic \; zone}$

The compensation level has nothing to do with the occurring in stratified lakes thermocline to do.

## literature

• Jürgen Schwoerbel, Heinz Brendelberger: Introduction to Limnology . 9th edition. Spectrum Academic Publishing House, 2005, ISBN 3-8274-1498-9 .

## Individual evidence

1. Thomas M. Smith et al .: Ecology . 6th edition. Pearson Education Deutschland GmbH, Munich 2009, ISBN 978-3-8273-7313-7 , p. 576 .
2. Jürgen Schwoerbel et al .: Introduction to Limnology . 9th edition. Elsevier GmbH, Munich 2005, ISBN 3-8274-1498-9 , p. 54, 130, 131 .