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(471) Outcome of the Portuguese monitoring program of cyanobacteria in freshwaters: more blooms detected, new toxins involved and new species observed. Vasconcelos, Vitor1,2, Pereira, Paulo3, Franca, Susana3, Dias, Elsa3, Tavares, Maria3, Cerqueira, Manuela1, Pereira, Elisa1,2, Saker, Martin1,2, Araujop, Filomena4, 1 2 3 4 ABSTRACT- This paper summarises the monitoring of cyanobacteria and associated toxins in Portuguese freshwaters since the mid 90s, emphasising the implications for water management and the need to improve monitoring strategies. Cyanobacteria contamination has being known to occur in Portugal and has recently being addressed as an health problem due to the associated toxin production. A survey on phytoplankton and their toxins during the past years showed an increase in the frequency of toxic blooms and an expanding list of problematic regions. The occurrence of blooms during winter as well as the vertical and horizontal dynamics of cyanobacteria is pointed out. Apart from the most commonly found species such as Microcystis aeruginosa, often associated with the production of microcystins, the production of paralytic shelfish toxins by Aphanizomenon sp. was also reported. The systematic observation of phytoplankton samples from several eutrophic lakes revealed the unexpected widespread presence of long lasting blooms of Cylindrospermopsis raciborskii a potentially harmful species commonly found in tropical areas. The sudden changes and year to year variations in phytoplankton density and composition as well as the increasing diversity of toxins potentially involved, makes the task of defining a good monitoring strategy for the water bodies difficult. This paper aims to contribute for the proper management of the water quality problems associated with cyanobacteria, arising in European and temperate countries. Key words: monitoring, cyanobacteria, toxins, freshwater |
