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Influence of Seiche‐Generated Light Field Fluctuations on Phytoplankton Growth
Author(s) -
Paul Lothar
Publication year - 1987
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19870720302
Subject(s) - seiche , hypolimnion , photic zone , epilimnion , internal wave , phytoplankton , light intensity , light field , atmospheric sciences , plankton , oceanography , environmental science , geology , physics , ecology , biology , optics , eutrophication , nutrient
Phytoplankton, owing to the periodic ascent and descent caused by internal seiches, is exposed to experiential fluctuations in light intensity. The increase in light intensity associated with its ascent towards the surface is greater than the decrease caused by its descent. A simple mathematical model is used to derive relationships showing that 1) the mean light intensity in an epilimnion influenced by internal waves is not more than 6.1% lower than in a stationary system and 2) in the meta‐ and hypolimnion of lakes of low transparency (i.e. with a high extinction coefficient) internal seiches of large amplitude increase the mean light intensity by several orders of magnitude. This can produce a many‐fold increase in the depth of the euphotic zone. The mean rates of photosynthesis of phytoplankton in the meta‐ and hypolimnion increase particularly at the antinodes of the waves. Internal seiches evidently may play an important role in causing plankton patchiness and in the presence of photosynthetically active phytoplankton at depths far below the 1% light limit.