Is the Change in the Nematological Biological Trait an Indicator of the Benthic Ecosystem Disturbance Following Sedimentary Enrichment in Micro-Sized Polyethylene (Pe-MPs): A Specific Focus on Free-Living Marine Nematofauna?

Free-living nematofauna are valuable biological indicators for different environmental disturbances. Their taxonomic structure and biological traits often respond to environmental changes. In our study, meiobenthic nematodes, collected from the Bizerte lagoon on the Tunisia northeastern coast, were examined in terms of their structure composition and functional traits after treatment with the utmost detected micro-sized polyethylene microplastics (PE-MPs) in marine biota. Three environmental PE-polymers levels: [PE1 (0.1 μg/g Dry weight (DW)), PE2 (1 μg/g DW), and PE3 (10 μg/g DW)], were progressively added and experiment was conducted for 30 days in the presence or absence of meiofauna assemblages. A lesser nematodes taxonomic structure was detected in all compartments tested. The non-parametric metric-multidimensional scaling (nMDS-2D plots) and the biological trait (relative abundances) of nematode species indicated that the change of all abundance. Nevertheless, all functional traits such as feeding diet, adult length, c-p score, tail shape, and amphid shape, exhibited a clear modification between the untreated and the treated compartments. The average dissimilarity between nematofauna species and biological traits groups augmented with PE-MPs-supplemented sediments. The nMDS second-stage ordination for matrices including nematodes species and functional traits displayed that the feeding diet was the closest to the taxonomic species distribution.

Keywords: PE-MPs Exposure, Nematodes Species, Population Response, Taxonomic Structure, Biological Traits.