Analysis of Variability in Embryological Response of Two Sea Urchin Species to Spatial and Temporal features-Can these Factors Influence Responses in Standardized Ecotoxicological Assays?

Abstract

Analysis of Variability in Embryological Response of Two Sea Urchin Species to Spatial and Temporal features-Can these Factors Influence Responses in Standardized Ecotoxicological Assays? The use of Echinoderms as bioindicator organisms, in particular in emryotoxicity test with Paracentrotus lividus and Arbacia lixula, has provided the scientific community with a remarkable number of ecotoxicological studies. In this experiment, the responses of these two species were analysed considering the spatial and temporal variability of three populations distributed in a radius of ca 10 km. The species tested in this experiment demonstrated an overall substantial different response towards metals (p<0.001), Arbacia lixula being the most sensitive species to both the three different sites and different periods of the year when adults were collected. There was a significant difference among populations for both species. The site affected most by the metal toxicity was Fortullino, which is the less human impacted area. In general, as a consequence of the passed reproductive season, embryos developed from gametes collected in May were the most affected in this study, confirming previous observations collected by our research group. No statistical difference has been recorded between the T1 (January) sampling corresponding to the beginning of reproductive season and the T5 (November) sampling-related embryos, which had the summer and the beginning of autumn as recovery period for their gamete production.