Driving factors behind the distribution of dinocyst composition and abundance in surface sediments in a western Mediterranean coastal lagoon: report from a high resolution mapping study.
Species composition and abundance of dinocysts in relation to environmental factors were studied at 123 stations of surface sediment in Bizerte Lagoon. Forty-eight dinocyst types were identified, mainly dominated by Brigantidinium simplex, Votadinum spinosum, Alexandrium pseudogonyaulax, Alexandrium catenella, and Lingulodinum machaerophorum along with many round brown cysts and spiny round brown cysts. Cysts ranged from 1276 to 20126 cysts g(-1)dry weight sediment. Significant differences in cyst distribution pattern were recorded among the zones, with a higher cyst abundance occurring in the lagoon's inner areas. Redundancy analyses showed two distinct associations of dinocysts according to location and environmental variables. Ballast water discharges are potential introducers of non-indigenous species, especially harmful ones such as A. catenella and Polysphaeridium zoharyi, with currents playing a pivotal role in cyst distribution. Findings concerning harmful cyst species indicate potential seedbeds for initiation of future blooms and outbreaks of potentially toxic species in the lagoon.
Institut Supérieur de Pêche et d'Aquaculture de Bizerte, Unité de recherche: Exploitation des Milieux Aquatiques, Errimel, B.P.15. 7080 Bizerte, Tunisia; Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249, France; Institut National des Sciences et Technologies de la Mer (INSTM), Centre la Goulette, Tunisia.
Mouna
M
Fertouna-Bellakhal
Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249, France; Institut National des Sciences et Technologies de la Mer (INSTM), Centre la Goulette, Tunisia.
Amel
A
Dhib
Institut National des Sciences et Technologies de la Mer (INSTM), Salammbô 2025, Tunisia.
Béchir
B
Béjaoui
Institut National des Sciences et Technologies de la Mer (INSTM), Centre la Goulette, Tunisia.
Souad
S
Turki
Université de Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS 6249, France. Electronic address: lotfi.aleya@univ-fcomte.fr.
Lotfi
L
Aleya
D000818:Animals; D003710:Demography; D004141:Dinoflagellida / Q000502:physiology*; D019015:Geologic Sediments; D008522:Mediterranean Sea; D012767:Ships; D014416:Tunisia; D014873:Water Pollutants
D014873:Water Pollutants
Bizerte Lagoon; Dinocysts; Enviromental factors; Hydrodynamics; Mapping