Éditeur(s) : HAL CCSD Cushman Foundation for Foraminiferal Research
Résumé : International audience
Benthic foraminifera are heterotrophic protists that utilize different trophic mechanisms and nutritional resources. They exhibit a wide range of trophic behaviours: selective (grazing) and indiscriminate herbivory, symbiosis, carnivory, parasitism, uptake of dissolved organic matter, passive suspension feeding and, most commonly, deposit feeding. The benthic foraminifera Ammonia tepida, previously known as an herbivore, fed as a carnivore in laboratory experiments where mobile metazoans were provided. We observed predation on the three types of metazoans provided: nematodes, copepods, and a larval gastropod. This foraminifera used its pseudopodial network to entrap the invertebrates, which were then stripped of their soft internal tissues within 24 hours. Our experiments are the first to demonstrate that Ammonia tepida, despite its limited motility, is able to utilize larger mobile animals as a food source. The great abundance of small metazoans in most marine environments suggests that they are a food source for foraminifera. Further study of foraminiferal feeding strategies will enhance our understanding of their role in marine communities.
ISSN: 0096-1191

hal-01248040
https://hal.archives-ouvertes.fr/hal-01248040
https://hal.archives-ouvertes.fr/hal-01248040/document
https://hal.archives-ouvertes.fr/hal-01248040/file/dupuy%20et%20al%202010.pdf

Éditeur(s) : Gauthier-Villars
Résumé : In developing countries, recourse to extensive aquaculture systems based on the exploitation of natural aquatic food webs is currently the subject of considerable interest. In this connection, the construction of artificial reefs (known as Acadja) for the development on substrates of living communities, and the utilization of this new production to enhance fish growth have been evaluated in Cote d'Ivoire. This paper describes the granulometric, chemical and biological transformation of the sedimentary ecosystem as a consequence of this practice. In the artificial habitat, an increase in the sedimentation rate of the mineral fraction (definitive trapping of particle resuspension generated by the waves and induced by the wind) and of the organic fraction (direct and indirect sedimentation of the epiphytic biomass) constitutes the starting point of significant modifications in epibenthic communities. In the Acadja, the meiofauna, dominated by nematodes and copepods, is somewhat less diversified, some groups being absent or poorly represented (turbellarians, gastrotrichs, ostracods). These characteristics were confirmed by a specific study of the nematode assemblages. In fact, the relatively high diversity of the nematode community in the natural lagoon sediment (dominated seasonally by Paraphanolaimus, Anonchus et Daptonema) contrasts with low diversity in the Acadja sediment, where the community is always dominated by Theristus sp. This lower specific diversity generates a reduction of the trophic types. In the Acadja, only the non-selective detritus feeders colonize the fine and organic sediment. These sedimentological and ecological transformations, which affect the entire ''brush park'' (Acadja), induce a strong eutrophication of the benthic ecosystem. Sustainable fish production in such tropical lagoons, in an environment where anaerobic processes dominate (especially sulfate-reduction), calls for strategic spatio-temporal planning to take of account of this progressive eutrophication.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1995 , Vol. 18 , N. 5 , P. 543-555

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00097/20796/18421.pdf
http://archimer.ifremer.fr/doc/00097/20796/