Le plankton: survivre et s'organiser dans un fluide mobile
Margalef, R. (1989). Le plankton: survivre et s'organiser dans un fluide mobile, in: Denis, M. (Ed.) Océanologie: actualité et prospective. pp. 169-185 In: Denis, M. (Ed.) (1989). Océanologie: Actualité et prospective. Centre d' Océanologie: Marseille. ISBN 2-907752-00-6. 387 pp., more |
| Abstract | Plankton answers to the same challenges to which the forest and the coral reef provide other kinds of responses. Physical contraints associated with fluidity and movement of water are most important. Ecological processes are discontinuously accelerated through the availability of external energy, apt to do work in mixing and upwelling. As soon as energy inputs are debilitated, pelagic ecosystems enter a more predictable path leading to a lower turnover with increasing segregation of the factors of production. Disturbances acting on an ecosystem can be arranged in a spectrum, with inverse relationship between frequences and amounts of involved energy (from big bang to daily rhythms). Models that lead to regular cycles and disregard space and thermodynamics do very poorly with plankton. Other models may provide a new viewpoint, but it is impossible to forget the real complexity of nature. Here the importance of the inputs of external energy, as a turbulence, and of the covariance in the distribution of the relevant factors of production is emphasized. This approach rejoins models in chemistry that study reactions under conditions of increasing organization or compartimentation of the reaction vessel. Derivation of the fundamental expressions with respect to time introduces ecological succession. Realism requires to work with spectra of the magnitudes concerned, however difficult it might be. |
|
