Species occurrence of the potentially toxigenic diatom genus Pseudo-nitzschia and the associated neurotoxin domoic acid in the Argentine Sea

ALMANDOZ, GASTÓN O.; FABRO, ELENA; FERRARIO, MARTHA; TILLMANN, URBAN; CEMBELLA, ALLAN; KROCK, BERND

HARMFUL ALGAE

ELSEVIER SCIENCE BV

Año: 2017 vol. 63 p. 45 - 55

1568-9883

The marine diatom genus Pseudo-nitzschia, the major known producer of the neurotoxin domoic acid (DA) responsible for the amnesic shellfish poisoning (ASP) syndrome in humans and marine mammals, is globally distributed. The genus presents high species richness in the Argentine Sea and DA has been frequently detected in the last few years in plankton and shellfish samples, but the species identity of the producers remains unclear. In the present work, the distribution and abundance of Pseudo-nitzschia species and DA were determined from samples collected on two oceanographic cruises carried out through the Argentine Sea (∼39?47°S) during summer and spring 2013. Phytoplankton composition was analysed by light and electron microscopy while DA was determined by liquid chromatography coupled to tandem mass spectrometry (LC?MS/MS). The genus Pseudo-nitzschia was recorded in 71 and 86% of samples collected in summer and spring, respectively, whereas DA was detected in only 42 and 21% of samples, respectively. Microscopic analyses revealed at least five potentially toxic species (P. australis, P. brasiliana, P. fraudulenta, P. pungens, P. turgidula), plus putatively non-toxigenic P. dolorosa, P. lineola, P. turgiduloides and unidentified specimens of the P. pseudodelicatissima complex. The species P. australis showed the highest correlation with DA occurrence (r = 0.55; p