Anatoxin-a occurrence and potential cyanobacterial anatoxin-a producers in Spanish reservoirs1

The presence of anatoxin-a (ANA) in Mediterranean region freshwaters has been reported only recently, and this work presents the first survey for ANA on a national scale in such waters. Fourteen reservoirs were sampled over a distance of 550 km from northeast to southwest Spain. Genera of cyanobacteria with ANA-producing members in other countries were present in all of the Spanish reservoirs, but this toxin was detected in only one reservoir. The maximum ANA concentration detected was 0.31 μg · L−1, and the most probable producer was Anabaena flos-aquae (Lyngb.) Breb. ex Bornet et Flahault. These findings suggest that in spite of the abundant cyanobacterial populations, ANA may be of lower occurrence in the Spanish reservoirs investigated than in other European freshwaters, and different strains of potential ANA producers occur in different ecoregions.