High Performance Liquid Chromatography pigments formation of microalgae growth during the development of Pseudo-nitzschia spp. of Cyanobacteria

Abstract

Pseudo-nitzschia blooms from the Ri'a de Pontevedra (NW Spain) were studied by light microscopy and HPLC pigment analysis. Two main Pseudo-nitzschia blooms were registered: the first one in summer had up to 800.000 cells L’ and the second in winter had up to 68.000 cells L'1. During the first bloom amnesic shellfish poisoning (ASP) was not detected and the dominant species was P. fraudulenta. During the second bloom ASP toxicity was detected, and the dominant species was P. australis. Pigment analyses from both blooms showed Chi c2 and Chi c3 as major components of the Chi c family, with Chi c a minor component. Although Chi c3 is usually associated with members of Prymnesiophyceae, Pelagophyceae and Dinophyceae, it has also been detected in Pseudo- nitzschia species as P. fraudulenta, P. delicatissima, P. pungens and P. pseudodelicatissima. However, chi c3 is not present in P. multiseries and P. australis, both able to synthesise domoic acid, the causative agent of ASP. The parallel increase of Chi c3 levels and Pseudo- nitzschia cell numbers (throughout the development of a quasi mono-specific blooms of Pseudo-nitzschia spp) can be used as preliminary information while domoic acid analysis and species identification by EM are performed.