Alexandrium pacificum Litaker sp. nov (Group IV): Resting cyst distribution and toxin profile of vegetative cells in Bizerte Lagoon (Tunisia, Southern Mediterranean Sea)

Mouna Fertouna-Bellakhal; Amel Dhib; Afef Fathalli; Meher Bellakhal; Nicolas Chomérat; Estelle Masseret; Mohamed Laabir; Souad Turki; Lotfi Aleya

doi:10.1016/j.hal.2015.07.007

Alexandrium pacificum Litaker sp. nov (Group IV): Resting cyst distribution and toxin profile of vegetative cells in Bizerte Lagoon (Tunisia, Southern Mediterranean Sea)

Harmful Algae. 2015 Sep:48:69-82. doi: 10.1016/j.hal.2015.07.007. Epub 2015 Aug 10.

Authors

Mouna Fertouna-Bellakhal¹, Amel Dhib², Afef Fathalli³, Meher Bellakhal³, Nicolas Chomérat⁴, Estelle Masseret⁵, Mohamed Laabir⁵, Souad Turki⁶, Lotfi Aleya⁷

Affiliations

¹ Université de Bourgogne Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS, 6249 Besançon, France; Institut Supérieur de Pêche et d'Aquaculture de Bizerte, Unité de recherche, Exploitation des Milieux Aquatiques, Errimel, B.P.15, 7080 Bizerte, Tunisie; Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette, La Goulette, Tunisie; Faculty of Sciences of Bizerte, FSB, Zarzouna, 7021 Bizerte, Tunisie.
² Université de Bourgogne Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS, 6249 Besançon, France; Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette, La Goulette, Tunisie.
³ Institut Supérieur de Pêche et d'Aquaculture de Bizerte, Unité de recherche, Exploitation des Milieux Aquatiques, Errimel, B.P.15, 7080 Bizerte, Tunisie.
⁴ IFREMER-Station de Biologie Marine, Place de la Croix, 29900 Concarneau, France.
⁵ UMR MARBEC 9190 IRD-Ifremer-UM-CNRS, Université de Montpellier, cc93, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.
⁶ Institut National des Sciences et Technologies de la Mer (INSTM), Laboratoire Milieu Marin, Centre la Goulette, La Goulette, Tunisie.
⁷ Université de Bourgogne Franche-Comté, Laboratoire de Chrono-Environnement, UMR CNRS, 6249 Besançon, France. Electronic address: lotfi.aleya@univ-fcomte.fr.

PMID: 29724478
DOI: 10.1016/j.hal.2015.07.007

Abstract

A high spatial resolution sampling of Alexandrium pacificum cysts, along with sediment characteristics (% H₂O, % organic matter (OM), granulometry), vegetative cell abundance and environmental factors were investigated at 123 study stations in Bizerte Lagoon (Tunisia). Morphological examination and ribotyping of cells obtained from a culture called ABZ1 obtained from a cyst isolated in lagoon sediment confirmed that the species was A. pacificum. The toxin profile from the ABZ1 culture harvested during exponential growth phase was simple and composed of the N-sulfocarbamoyl toxins C1 (9.82pgtoxincell^-1), the GTX6 (3.26pgtoxincell^-1) and the carbamoyl toxin Neo-STX (0.38pgtoxincell^-1). The latter represented only 2.8% of the total toxins in this strain. High abundance of A. pacificum cysts correlated with enhanced percentages of water and organic matter in the sediment. In addition, sediment fractions of less than 63μm were examined as a favorable potential seedbed for initiation of future blooms and outbreaks of A. pacificum in the lagoon. A significant difference in the cyst distribution pattern was recorded among the lagoon's different zones, with the higher cyst abundance occurring in the inner waters. Also, no correlation due to the specific hydrodynamics of the lagoon was observed in the spatial distribution of A. pacificum cysts and vegetative cells.

Keywords: Alexandrium pacificum Litaker sp. nov (Alexandrium catenella-group IV (Whedon & Kofoid), Balech); Cysts; Mapping; Ribotype; Toxin profile; Vegetative cells.