Occurrence of harmful dinoflagellates in the punic harbors of Carthage (Gulf of Tunis, Tunisia) and their correlations with the physicochemical parameters.

Abstract

In order to provide a better understanding of dinoflagellates structure and their relationship with environmental parameters in typical semi-enclosed areas communicating with the gulf of Tunis, a study was carried out to estimate the dinoflagellate assemblage structure and nutrients contents in seven stations during a semi-annual survey (from January to June 2006) in Punic harbors of Carthage (gulf of Tunis, south Mediterranean Sea). 66 species of dinoflagellates were identified among which 14 species are known to be harmful and responsible for farmful blooms and 21 species are known to be producing toxins. Statistical analysis showed significant correlations between many species, such as: Dinophysis sacculus, D. acuminata, Alexandrium spp, Gymnodinium. aureolum, Gymnodinium impudicum, Akashiwo sanguinea, Scrippsiella spp and Prorocentrum gracile with water temperature and orthophosphate concentrations.