Dynamics of Dinophysis sensu lato species (Dinophyceae) in a coastal Mediterranean environment (Adriatic Sea)

Species of Dinophysis Ehrenberg sensu lato were collected opportunistically along the southern Adriatic coasts (Apulia, Italy) during a survey of phyt oplankton community structure and dynamics carried out from 1995 to 1997. M ost previous reports of Dinophysis spp. in the Adriatic Sea concentrated on northern populations, with few data available on phytoplankton inhabiting the southern coastal areas. Thus, the present study is the first on Dinophy sis sensu lato species composition and spatio-temporal distribution in thes e essentially oligotrophic waters. Twelve Dinophysis species were identifie d; some of which can be assigned to the genus Phalacroma. Dinophysis saccul us, D. fortii, D. caudata, Phalacroma rotundatum and P. mitra are potential ly producers of diarrhetic shellfish poisoning. Seasonal changes in Dinophy sis and Phalacroma populations are presented, as well as their relationship s with hydrographic and biotic factors. These dinoflagellates were associat ed with mixing conditions, low water temperatures and high nutrient inputs. Furthermore, the statistical analysis evidenced significant correlations o f Dinophysis species to chlorophyll a and phytoplankton. Ecological implica tions arising from the data are discussed. (C) 2001 Elsevier Science Ltd. A ll rights reserved.