Dinoflagellate resting cysts from surface sediments of the Adriatic Ports: distribution and potential spreading patterns

The ability of microalgae to preserve viable in coastal sediments as resting forms provides a reservoir of bio- diversity and a useful tool to determine species spreadings. This study represents the first port baseline survey on dinoflagellate cysts, investigated in nine Adriatic ports during a cross border project. 40 dinoflagellate taxa were detected. The assemblages resulted in all ports dominated by Lingulodinium polyedra and Alexandrium minutum/ affine/tamutum group. General separation to the western and eastern side of the Adriatic regarding cysts as- semblage composition, partially abundance, was observed. Six taxa were detected as non-indigenous species for the Adriatic. Two taxa are included in the list of harmful aquatic organisms, indicating the potential threat of ballast waters in the Adriatic. Potential spreading of taxa by general circulation and ballast waters, intra- and extra-Adriatic was investigated. The entering in to force of the ballast waters management regulations should enhance prospects to minimize future harmful impacts.