Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays

Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid Quinquelaophonte sp., and in the planktonic calanoid Gladioferens pectinatus, two New Zealand copepod species. The sediment samples from the estuary tributary sites significantly impacted reproduction in Quinquelaophonte sp. However, results from one of the estuary sites were not significantly different to those from the tributaries sites, suggesting that chemicals other than trace metals, polycyclic aromatic hydrocarbons and ammonia may be the causative stressors. Sediment elutriate samples had significant effects on reproductive endpoints in G. pectinatus, and on the induction of DNA damage in cells, as shown by the comet assay. The results indicate that sediment contamination at the Ahuriri Estuary has the potential to impact biological processes of benthic and pelagic organisms. The approach used provides a standardized methodology to assess the toxicity of estuarine sediments.

Seasonal variability in diversity and abundance of the free-living pelagic copepod community of the Algerian coasts (SW Mediterranean Sea)

Investigations on the free-living, pelagic copepod community of the Algerian coasts were performed at the Habibas Islands and in Bou Ismail Bay (Sidi Fredj coast) between 0 and 100 meter depth during various seasons of the year 2012-2013. Seventy-seven taxa at species level have been identified, belonging to 47 genera and 24 families. The distribution of the copepod community revealed seasonal variability; high abundance and species richness (greater than 20 species) characterized winter and spring, while the summer period was characterized by low abundance and species richness. The spatial distribution showed high abundance and species richness on the Sidi Fredj coast (the respective mean abundances along the Sidi Fredj coast and at the Habibas Islands were 253.71 ind.m−3 and 109.77 ind.m−3, respectively). Analysis of the samples showed the presence of seven abundant and frequent species: Centropages typicus, Eucalanus elongatus, Pleuromamma abdominalis, Paracalanus parvus, Paracalanus nanus, Calanus helgolandicus, and Temora stylifera. Multivariate analysis (ascending hierarchical classification and non-metric multidimensional scaling) enabled us to group the stations according to the composition in the copepod species, and the influence of seasonal changes was well observed. A dominance of herbivorous behaviour, followed by an omnivorous feeding strategy, was observed in the two studied areas. A dominance of epipelagic and epi-mesopelagic species was observed during all seasons, reflecting a neritic character of both study areas.