title: Dynamics of the toxin cylindrospermopsin and the cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum in a Mediterranean eutrophic reservoir.
abstract: Chrysosporum ovalisporum is a cylindrospermopsin toxin producing cyanobacterium that was reported in several lakes and reservoirs. Its growth dynamics and toxin distribution in field remain largely undocumented. Chrysosporum ovalisporum was reported in 2009 in Karaoun Reservoir, Lebanon. We investigated the factors controlling the occurrence of this cyanobacterium and vertical distribution of cylindrospermopsin in Karaoun Reservoir. We conducted bi-weekly sampling campaigns between May 2012 and August 2013. Results showed that Chrysosporum ovalisporum is an ecologically plastic species that was observed in all seasons. Unlike the high temperatures, above 26 °C, which is associated with blooms of Chrysosporum ovalisporum in Lakes Kinneret (Israel), Lisimachia and Trichonis (Greece) and Arcos Reservoir (Spain), Chrysosporum ovalisporum in Karaoun Reservoir bloomed in October 2012 at a water temperature of 22 °C during weak stratification. Cylindrospermopsin was detected in almost all water samples even when Chrysosporum ovalisporum was not detected. Chrysosporum ovalisporum biovolumes and cylindrospermopsin concentrations were not correlated (n = 31, r² = -0.05). Cylindrospermopsin reached a maximum concentration of 1.7 µg L⁻¹. The vertical profiles of toxin concentrations suggested its possible degradation or sedimentation resulting in its disappearance from the water column. The field growth conditions of Chrysosporum ovalisporum in this study revealed that it can bloom at the subsurface water temperature of 22 °C increasing the risk of its development and expansion in lakes located in temperate climate regions.
authors.affiliation: Laboratory of Microorganisms and Food Irradiation, Lebanese Atomic Energy Commission-CNRS, P.O. Box 11-8281, Riad El Solh, Beirut 1107 2260, Lebanon. ali.fadel@leesu.enpc.fr.
authors.forename: Ali
authors.initials: A
authors.lastname: Fadel
authors.affiliation: Laboratory of Microorganisms and Food Irradiation, Lebanese Atomic Energy Commission-CNRS, P.O. Box 11-8281, Riad El Solh, Beirut 1107 2260, Lebanon. a.atoui@cnrs.edu.lb.
authors.forename: Ali
authors.initials: A
authors.lastname: Atoui
authors.affiliation: LEESU (UMR MA-102) Université Paris-Est, Ecole des Ponts ParisTech, AgroParisTech, Marne-la-Vallée F-77455, France. bvl@leesu.enpc.fr.
authors.forename: Bruno J
authors.initials: BJ
authors.lastname: Lemaire
authors.affiliation: LEESU (UMR MA-102) Université Paris-Est, Ecole des Ponts ParisTech, AgroParisTech, Marne-la-Vallée F-77455, France. bvl@leesu.enpc.fr.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Vinçon-Leite
authors.affiliation: Laboratory of Microorganisms and Food Irradiation, Lebanese Atomic Energy Commission-CNRS, P.O. Box 11-8281, Riad El Solh, Beirut 1107 2260, Lebanon. kslim@cnrs.edu.lb.
authors.forename: Kamal
authors.initials: K
authors.lastname: Slim
mesh_terms: D000470:Alkaloids; D046890:Aphanizomenon / Q000254:growth & development* / Q000378:metabolism; D001427:Bacterial Toxins / Q000032:analysis* / Q000096:biosynthesis; D018533:Biomass; D000087522:Cyanobacteria Toxins; D005068:Eutrophication; D007861:Lebanon; D010798:Phycocyanin / Q000032:analysis / Q000096:biosynthesis; D010839:Phytoplankton / Q000254:growth & development* / Q000378:metabolism; D012621:Seasons; D013696:Temperature; D014498:Uracil / Q000031:analogs & derivatives* / Q000032:analysis / Q000096:biosynthesis; D014871:Water Microbiology; D014877:Water Pollution, Chemical; D060753:Water Quality; D062066:Water Resources / Q000032:analysis*; D014887:Weather
chemical_list: D000470:Alkaloids; D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D010798:Phycocyanin; C089595:cylindrospermopsin; D014498:Uracil