Response of potentially toxic Pseudo-nitzschia (Bacillariophyceae) populations and domoic acid to environmental conditions in a eutrophied, SW Mediterranean coastal lagoon (Tunisia)

摘要: Abstract The population dynamics of Pseudo-nitzschia species from Bizerte Lagoon, northern Tunisia, were examined at six stations sampled monthly March 2006 to February 2007. These are potential producers the neurotoxin domoic acid (DA), cause amnesic shellfish poisoning (ASP). Six morphospecies counted: brasiliana , calliantha delicatissima complex species, multistriata pseudodelicatissima and ‘ Nitzschia seriata ’ group species. Canonical correspondence analysis was used correlate with physical chemical properties seawater, statistical significance species-variable associations tested using Van Dobben method. P. delicatissima abundance significantly positively correlated turbidity, negatively associated temperature, nitrate, silicate DA. P. brasiliana more abundant in samples higher salinity, DA, lower nitrite, phosphate turbidity. P. multistriata linked salinity temperature Abundances P. calliantha P. pseudodelicatissima N. seriata not statistically related any variables examined. We document, for first time, incidence DA Lagoon (at four stations) one offshore station Bay (Mediterranean Sea). Total ranged 0.5 2.0 μg DA l −1 detected only October 2006, when lagoon waters rich nitrate elevated. beginning autumn highest risk period ASP events, elevated growth. findings allow local jurisdictions prepare bloom provide data eventual predictive models formation toxin production comparison elsewhere world.