Is Changing in Feeding-Groups Nematode as an Indicator of an Ecosystem Disturbed by Ciprofloxacin/Bde-47 Combined Exposure?

A laboratory bioassay was executed to examine the combined environmental concentrations ecotoxicity of two type emerging pollutants, on meiobenthic taxa especially, marine free- living nematodes. After 30 days’ experiment incubation, the meiobenthic taxa average density, the specific structure as well as the biological traits of nematofauna presented significant differences between the control and mixture groups. All taxa abundance decreased significantly with all concentrations applied, particularly with the highest, M2. Only species number (S) and species richness (d) were affected significantly in the same compartment, while Shannon diversity (H’) and Pielou’s evenness (J’) did not show any variation in nematodes. A taxonomic restructuring has been recorded in correlation with abundance decrease of species from trophic groups 1A: ie., Terchellengia Longicaudata, Terchellengia communis; 1B: ie., Odontophora villoti, Paramonohysteria pilosa, and also, to the abundance increase of species belonging to trophic groups 2A: represented by Paramonohysteria pilosa, and 2B: ie., Metoncholaimus pristiurus, Oncholaimellus mediterraneus. In addition, the relative abundances of each nematode biological trait assemblages were touched and revealed that, amphid shape, life history and feeding group, showed a strong difference among the control and the treated compartment, and only the first biological trait mentioned was the closest to the taxonomic species distribution.

Keywords: Ciprofloxacin/BDE-47 exposure, Meiobenthic taxa, Meiobenthic nematodes, Taxonomic structure, Biological traits.