title: Environmental factors associated with phytoplankton succession in a Mediterranean reservoir with a highly fluctuating water level.
abstract: Eutrophication and harmful algal blooms have become a worldwide environmental problem. Understanding the mechanisms and processes that control algal blooms is of great concern. The phytoplankton community of Karaoun Reservoir, the largest water body in Lebanon, is poorly studied, as in many freshwater bodies around the Mediterranean Sea. Sampling campaigns were conducted semi-monthly between May 2012 and August 2013 to assess the dynamics of its phytoplankton community in response to changes in physical-chemical and hydrological conditions. Karaoun Reservoir is a monomictic waterbody and strongly stratifies between May and August. Changes in its phytoplankton community were found to be a result of the interplay between water temperature, stratification, irradiance, nutrient availability and water level. Thermal stratification established in spring reduced the growth of diatoms and resulted in their replacement by green algae species when nutrient availability was high and water temperatures lower than 22 °C. At water temperature higher than 25 °C and low nutrient concentrations in summer, blooms of the cyanobacterium Microcystis aeruginosa occurred. Despite different growth conditions in other lakes and reservoir, cyanobacterium Aphanizomenon ovalisporum dominated at temperatures lower than 23 °C in weakly stratified conditions in early autumn and dinoflagellate Ceratium hirundinella dominated in mixed conditions, at low light intensity and a water temperature of 19 °C in late autumn. We believe that the information presented in this paper will increase the knowledge about phytoplankton dynamics in the Mediterranean region and contribute to a safer usage of reservoir waters.
authors.affiliation: Université Paris-Est, LEESU (UMR MA-102)l, Université Paris-Est-Créteil, Ecole des Ponts ParisTech, AgroParisTech, F-77455, Marne-la-Vallée, France. afadel@cnrs.edu.lb.|National Center for Remote Sensing, National Council for Scientific Research (CNRS), P.O. Box 11-8281, Riad El Solh, Beirut, 1107 2260, Lebanon. afadel@cnrs.edu.lb.
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: Université Paris-Est, LEESU (UMR MA-102)l, Université Paris-Est-Créteil, Ecole des Ponts ParisTech, AgroParisTech, F-77455, Marne-la-Vallée, France. bruno.lemaire@leesu.enpc.fr.|AgroParisTech, F-75005, Paris, France. bruno.lemaire@leesu.enpc.fr.
authors.forename: Bruno J
authors.initials: BJ
authors.lastname: Lemaire
authors.affiliation: Université Paris-Est, LEESU (UMR MA-102)l, Université Paris-Est-Créteil, Ecole des Ponts ParisTech, AgroParisTech, F-77455, Marne-la-Vallée, 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: D000460:Chlorophyta / Q000254:growth & development; D000458:Cyanobacteria / Q000254:growth & development; D004784:Environmental Monitoring / Q000379:methods*; D005068:Eutrophication; D005618:Fresh Water / Q000737:chemistry*; D007861:Lebanon; D008522:Mediterranean Sea; D010839:Phytoplankton / Q000254:growth & development*; D012621:Seasons; D012623:Seawater / Q000737:chemistry*; D013696:Temperature
keywords: Cyanobacteria; Irradiance; Middle East; Nutrients; Thermal stratification