Quantification of the toxic dinoflagellate Ostreopsis spp. by qPCR assay in marine aerosol

Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) Synthesis Open Science Meeting, 24-26 April 2013, Paris, FranceMarine aerosols are airborne particles of biological origin containing algal cells, bacteria, spores, and viruses, which are carried out by bubbles to the sea surface microlayer and to the atmosphere. Since the summer of 2005, in the Mediterranean Sea, growing concerns regarding exposure to harmful marine aerosols associated with toxic benthic dinoflagellate Ostreopsis spp. blooms have been reported, as they represent major health and economic risks to human populations. Toxic events in humans after inhalation or cutaneous contact have been reported during O. cf. ovata blooms and were attributed to palytoxin (PLTX)-like compounds produced by this microalga. In this context, we developed a qPCR assay for the estimation of the toxic benthic dinoflagellate Ostreopsis cf. ovata in the complex matrix of marine aerosol at Sant Andreu de Llavaneres (northwestern Mediterranean Sea) during a bloom together with a determination of PLTX-like compounds using hemolytic assay and liquid chromatography. Marine aerosol samples collected at two stations were analyzed by qPCR. The sensitivity was set at two rDNA copy number and 8 × 10¿4 cell per reaction. Results showed that O. cf. ovata abundance in marine aerosol during the bloom varied in the range of 1¿102 cells per filter. No PLTX was detected in the aerosol filters by analytical determinations, while the estimation of PLTX like-compound concentrations in microepiphytic assemblages varied between 0.1 and 1.2 pg/cell. In conclusion, the developed qPCR assay is a highly sensitive and specific quantification method for toxic O. cf. ovata in a complex matrix, such as marine aerosolPeer Reviewe