Meiofaunal colonisation on artificial substrates: a tool for biomonitoring the environmental quality on coastal marine systems.

The use of artificial substrates for monitoring environmental quality and contaminant impact has been repeatedly suggested, but little information is yet available on the applicability and the sensitivity of this approach. One of the crucial points to be addressed for using artificial substrates, as tools mirroring actual benthic community state, is assessing whether, and how, they reflect in situ conditions characterising natural sediments. In this study we investigated short-term dynamics of meiofaunal colonisation on artificial substrates (bottle brushes) deployed in impacted and "pristine" (control) sites. Meiofaunal colonisation reached a threshold level after 4-6 days in both impacted and control sites but with significantly higher densities in artificial substrates deployed in the control site. Meiofaunal parameters in artificial substrates reflected those of meiofaunal assemblages inhabiting natural sediments where artificial substrates were deployed. Colonised artificial substrates were then transplanted from impacted to control sites. This caused a significant increase of meiofaunal abundance, which after 5 days reached values indistinguishable from the non-impacted control. Given the rapid colonisation time, meiofaunal sensitivity to changing environmental conditions, it can be concluded that artificial substrates can represent an useful tool to be further developed for routine and low-cost monitoring studies aiming at integrating biological indicators of environmental quality.