Harmful algal species in beach environments along the Sardinian coasts: an interdisciplinary approach for prediction and mitigation of noxious events

"Blooms of noxious phytoplankton species are recurrent events in marine coastal waters and can cause negative impacts on human health, natural resources, aquaculture farming, tourism, and, in general, on the whole aquatic ecosystem. In recent years, reports of harmful algal blooms in beaches along Mediterranean coasts have increased significantly, likely due to a high vulnerability of marine environments to these events. Species that have been more involved are Alexandrium taylorii Balech and Ostreopsis cf. ovata Fukuyo. Knowledge on the presence, distribution and bloom dynamics of harmful species in the NW Mediterranean beaches is well established, especially along the Spanish coast (Catalonia and Balearic Islands), whereas it is really scarce in Sardinia, the largest island in the NW Mediterranean Sea. To start to fill these gaps, we designed a three-year scientific project that started in June 2012, funded by the Autonomous Region of Sardinia. The general aim is to improve the ability to predict and mitigate impacts of harmful algal blooms in areas of high economic interest (e.g. beaches for tourism), through the use of an interdisciplinary approach. In summer 2012 a first sampling survey on 74 beaches was conducted. This enabled us to acquire information on the presence and distribution of target harmful species (A. taylorii and Ostreopsis species) and on related basic environmental conditions (e.g., physical-chemical parameters, nutrients, sediment grain size, pattern and dynamics of water currents). Harmful algal species were identified and quantified using the microscopic methods. Moreover, identification of several target harmful algal species has been also done using molecular PCR methods. Preliminary data revealed a high frequency of observations of A. taylorii in a wide range of environmental conditions whereas O. cf. ovata was recorded only in few samples."