Prevalence of paralytic shellfish poison-producing Planktothrix agardhii and Cylindrospermopsis raciborskii in a Brazilian semi-arid reservoir

Dominância de cianobactérias Planktothrix agardhiie Cylindrospermopsis raciborskii, produtoras de toxina paralisante de molusco, em reservatório na região semiárida brasileira

Abstracts

Aim: The present study aimed to investigate the composition and toxicity of the phytoplankton in Sítios Novos reservoir, used mainly as drinking water supply for approximately 30,000 people.

Methods  Samples were collected between January 2010 and June 2011.

Results  During this period 19 taxa of cyanobacteria and 22 of algae were identified. Out of 45 samples collected, algae accounted for no more than 10% of the quantified organisms in 44 samples. Cyanobacteria accounted for 100% of the organisms quantified in three samples and for 99% in other 29 samples. Among the cyanobacteria group, Planktothrix agardhii (Gomont) Anagnostidis & Komárek and Cylindrospermopsis raciborskii (Woloszynska) Seenaya & Subbaraju prevailed and both strains were isolated and identified as paralytic shellfish poison (PSP) producers. C. raciborskii strain has shown to produce SXT and dcSXT while P. agardhii strain has shown to produce dcGTX2 or 3.

Conclusions  To the author’s knowledge, this is the first report of PSP-producer cyanobacteria species isolated in Northeastern Brazil and the first reported of a P. agardhii synthesizing dcGTX2/3.

phytoplankton; saxitoxins; HPLC; ELISA; water quality