Toxic algal blooms along the urban coast: a citizens' point of view

In this study, a Citizens’ Observatory, the Osservatorio del Mare a Molfetta (OMM), has monitored the proliferation of the toxic microalgae Ostreopsis ovata along the coast of Molfetta, an Italian city on the Southern Adriatic Sea, where blooms have been reported since summer 2009. To establish an alternative low cost and effective monitoring protocol, planktonic cells were counted for four years in seawater sampled at two stations along the urban coast. we show that: (i) O. ovata blooms occur along the coast of the city of Molfetta; (ii) the presence of O. ovata was detected from May up until January of the following year; (iii) blooms of O. ovata are concomitant with those of non-toxic diatoms of the genus Coscinodiscus, which were predominant in the phytoplankton community; (iv) during the time frame of this study, Ostreopsis and Coscinodiscus proliferation start at the station closest to the urban centre. The traditional O. ovata-monitoring protocols, based on single sampling station/city every 15 days between June and September, need improvement. The weekly sampling of seawater along the urban coast from June to January is an effective and low-cost method to predict toxic algal blooms in our city. As a local citizen’s observatory, we intend to support traditional monitoring programs by providing our data set to improve the surveillance.