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Caractéristiques du microphytobenthos d'un lac volcanique. Characterization of the Microphytobenthos in a Volcanic Meromictic Lake (Lake Pavin, France). II. Productivity and Relationships
Author(s) -
Romagoux JeanClaude
Publication year - 1980
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.19800650608
Subject(s) - productivity , primary productivity , photosynthesis , environmental science , volcano , population , ecology , geology , botany , biology , ecosystem , geochemistry , demography , macroeconomics , sociology , economics
The collection of microphytobenthos for primary production studies in Lake Pavin was performed with a Jenkin sampler. This corer permits sampling at different levels below the surface of the lake. Five levels (10, 20, 30, 40, and 60 m below the surface) were regularly investigated for more than one year. Each was inhabited by a characteristic population of dominant diatoms. The primary production, which was very large during the summer, decreases with depth. During the winter, the 14 C assimilation occurs at a very low rate in clear incubators, but in dark incubators, the rate is high. Therefore, the 14 C fixation in darkness is greater than the photosynthetic assimilation. This phenomenon together with the very important data recorded for photosynthetic efficiency (especially at the lowest levels, 40 and 60 m deep) suggest that microphytes on the bottom of the lake assimilate organic compounds during much of the year.