Phytoplankton diversity in Adriatic ports

Besides being a highly sensitive ecosystem, the Adriatic Sea is also an important seaway for international and local shipping, which poses a serious risk on the transfer of harmful aquatic organisms and pathogens (HAOP) by ships. Monitoring programs and surveillance activities would be of limited efficacy if carried out on a local scale only. The first step in setting up a common Adriatic approach towards unwanted threats to the environment from the transfer of HAOP was to prepare an inventory of organisms in ports. Phytoplankton diversity was determined through the port baseline survey in twelve Adriatic ports in years 2011, 2014 and 2015. Phytoplanktonic HAOP were identified as species, either native or non-indigenous (NIS) that can trigger harmful algal blooms (HAB). A list of 689 taxa was prepared and among them 52 were classified as HAB and five as NIS. Records of toxigenic NIS (Pseudo-nitzschia multistriata, Ostreopsis species including O. cf. ovata) indicate that the intrusion of non-native invasive phytoplankton species has already occurred in some Adriatic ports. The seasonal occurrence and abundance of HAOP offers a solid baseline for a monitoring design in ports in order to prevent possible expansion of HAOP outside their native region.