Dysphotic zone
The dysphotic zone , also diphotische zone or twilight zone is, in waters of weakly illuminated by depth range of the Mesopelagials which is located at the photic zone adjoins. Effective photosynthesis is no longer possible here. However, there is still enough light of visible wavelengths available to enable the animals living here to see and orient themselves ( phototaxis ). In the absence of phytoplankton , the animals in the dysphotic zone either feed themselves carnivorously, i.e. from other animals, or detritivorously , from dead organic material ( sea snow ). In the twilight zone there are particularly many bioluminescent organisms.
The depth range of the dysphotic zone depends on the clarity of the water; in murky coastal waters it can begin at a depth of less than 1 m. In the clearest oceanic water, the dysphotic zone begins at a maximum depth of 200 m and ends at a maximum of 1000 m. No more light can be detected below this zone and the aphotic zone begins .
Individual evidence
- ↑ dysphotic. In: Lexicon of Geosciences. Retrieved June 14, 2019 .
- ↑ a b Twilight Zone. In: Spectrum Lexicon of Biology. Retrieved June 14, 2019 .
- ^ A b Sigrid Schiel, Barbara Niehoff: Das Pelagial . In: Gotthilf Hempel, Irmtraut Hempel, Siegrid Schiel (eds.): Fascination Marine Research . HM Hauschild, Bremen 2006, ISBN 3-89757-310-5 , p. 27 .