Tropholytic zone
The tropholytic zone (from the Greek trophe diet; lytikos dissolving), which is also called the depletion layer or degradation zone , is the light-poor to lightless depth area of stagnant water . In this zone, due to lack of light, photosynthesis is less than simultaneous breathing. Therefore there is a breakdown of organic matter in the balance. Plants have no growth here. Instead, animals with a heterotrophic diet live in the tropholytic zone . Also there living and dead organic material ( detritus ), which sinks in the water, is broken down by bacteria and destructors .
This layer is often mistakenly identified with the hypolimnion . In fact, in very clear lakes the trophogenic layer can extend far into the hypolimnion during the day, while in very eutrophic and therefore cloudy lakes even part of the epilimnion can be tropholytic. Furthermore, since the limit of light, which decides between predominant photosynthesis and predominant respiration ("compensation depth"), changes with the weather, the course of the day and the season, the tropholytic layer can, like the trophogenic layer, only in connection with a time base determined, which depends on the question.
See also
Web links
- The term lake and the zoning ( Memento of October 10, 2007 in the Internet Archive )