Eutrophie et pollution: structure et fonctionnement du sous-écosystème planktonique = Eutrophy and pollution: structure and mechanism of the planktonic sub-ecosystem
Blanc, F.; Leveau, M.; Kerambrun, P. (1976). Eutrophie et pollution: structure et fonctionnement du sous-écosystème planktonique = Eutrophy and pollution: structure and mechanism of the planktonic sub-ecosystem, in: Persoone, G. et al. (Ed.) Proceedings of the 10th European Symposium on Marine Biology, Ostend, Belgium, Sept. 17-23, 1975: 2. Population dynamics of marine organisms in relation with nutrient cycling in shallow waters. pp. 61-83 In: Persoone, G.; Jaspers, E. (Ed.) (1976). Proceedings of the 10th European Symposium on Marine Biology, Ostend, Belgium, Sept. 17-23, 1975: 2. Population dynamics of marine organisms in relation with nutrient cycling in shallow waters. European Marine Biology Symposia, 10(2). IZWO/Universa Press: Wetteren. ISBN 90-6281-002-0. 712 pp., more In: European Marine Biology Symposia., more |
| Available in | Authors | | Document type: Conference paper
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| Authors | | Top | - Blanc, F.
- Leveau, M.
- Kerambrun, P.
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| Abstract | The organization of the planktonic sub-ecosystem is considered at the same time from its architectural and functional aspect, in heavily eutrophied and polluted areas: the Rhone delta, the Gulf of Fos, and the pond of Berre. Besides the classical study of the sub-ecosystem structure by qualitative and quantitative estimation of the zoo- and phytoplankton populations, the authors examined its mechanism by measuring an array of physical, chemical, and physiological parameters. The management of this enormous data bank could only be realized with computers and led to the use of heuristic mathematical methods. In these regions the ecosystem has always a relatively young aspect. Depending on the zones, the maturation process is initiated at different times, and are then more or less rapidly halted by the arrival of new ecological compulsions which result in a mosaic of regions with a more or less organized structure (negentropy measured by the diversity index of Shannon is usually less than 3 bits/cell for the phytoplankton and 5 bits/cell for the zooplankton). This structural aspect seems to be confirmed at the mechanism level by the enzymograms derived from the zooplanktonic populations. Certain interesting trophic relations have been demonstrated. The differential assimilation of nutritive elements by the phytoplankton populations consisting of one or a few species, rapidly leads to an imbalance of the N/P ratio accompanied by an increase of the diversity index. Some zooplanktonic associations easily tolerate pollution. In the polluted areas, the copepods Acartia clausi, A. discaudata, A. latisetosa, and the cladoceran Podon polyphemoldes, find extremely favorable trophic conditions which can be explained as a mechanism of exclusion. Organisms at the second trophic level are numerous due to the nutriment abundance consisting of Dinoflagellates. |
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