Effects of organic enrichment on nematode assemblages in a microcosm experiment

Maickel Armenteros (1, 2) , José Andrés Pérez-García (1) , Alexei Ruiz-Abierno (1) , Lisbet Díaz-Asencio (3) , Yusmila Helguera (3) , Magda Vincx (2) , Wilfrida Decraemer (4, 5)

1 Universidad de La Habana [Cuba]
2 Marine Biology Section
3 Ministerio de Ciencia
4 RBINS - Royal Belgian Institute of Natural Sciences
5 Nematology Section

Marine nematodes from subtidal tropical sediments of Cienfuegos Bay were subjected to organic enrichment in a microcosm experiment for 32 days. Nematode abundance and diversity decreased, and the taxonomic and trophic structure was altered. The results suggested that the nematodes were not food limited in the microcosms or in their natural environment. Chemical stressors such as ammonia and hydrogen sulfide derived from reduced conditions in sediments may be important factors affecting the assemblages. Hypoxic conditions occurred in all experimental units, as well as in the field, suggesting a nematode assemblage adapted to naturally enriched sediments. However, tolerant species showed a grade of sensitivity to reduced conditions. In agreement with the model by Pearson and Rosenberg (1978), we predict that further organic enrichment in sediments from Cienfuegos Bay may cause a phase shift into a strongly depleted benthic fauna and reduced conditions in water and sediments.

Mots clés: nematodes; organic enrichment; microcosm; hypoxia; tropical; community composition; effects-community; Caribbean Sea

Maickel Armenteros, José Andrés Pérez-García, Alexei Ruiz-Abierno, Lisbet Díaz-Asencio, Yusmila Helguera, et al.. Effects of organic enrichment on nematode assemblages in a microcosm experiment. Marine Environmental Research, 2010, 70 (5), pp.374. ⟨10.1016/j.marenvres.2010.08.001⟩. ⟨hal-00631696⟩