Toxic Pseudo-nitzschia populations from the Middle Tyrrhenian Sea (Mediterranean Sea, Italy)

Abstract

Several diatoms of the genus Pseudo-nitzschia are able to produce domoic acid (DA), a neurotoxic aminoacid responsible for Amnesic Shellfish Poisoning (ASP) in humans and animals worldwide. Pseudo-nitzschia spp. are widespread along Italian coast, however current knowledge of their diversity, temporal succession and potential toxicity is limited to restricted areas. Blooms of these diatoms have been increasingly recorded along the Latium region coast (Middle Tyrrhenian Sea, Mediterranean Sea) in the last decades prompting investigation of Pseudo-nitzschia diversity and potential toxicity in natural communities from coastal stations over one year. Results of the taxonomical analysis are here reported together with distribution data, at species complex resolution, that were collected during a regional long-term program. Transmission electron microscopy on acid cleaned frustules ascertained the presence and identity of eight Pseudo-nitzschia species, six of which are known ASP producers. One species, P. inflatula, is reported for the first time from Italian waters. Distributional data evidenced coexistence of different species during blooms, seasonal cycles and inter-annual variability, abundances of the genus reached 107 cell/l-1. © 2008 Springer Science + Business Media B.V.