title: Effects of trophic status on microcystin production and the dominance of cyanobacteria in the phytoplankton assemblage of Mediterranean reservoirs.
abstract: The aim of our study was to evaluate the abundance of cyanobacteria and microcystins in four Sardinian reservoirs (Italy) characterised by different trophic status to define a reference picture for future changes. Increasing levels of eutrophication and the abundance of cyanobacteria are expected to occur due to climate change, especially in the southern Mediterranean. Consequently, an in-depth study of the occurrence of harmful cyanobacteria is important to develop appropriate management strategies for water resources at a local scale. Monthly samples were collected at one station in each reservoir over an 18-month period. The Analysis of similarity indicated that cyanobacterial abundance and species composition differed significantly among the reservoirs. The Redundancy analysis highlighted their relationship to trophic, hydrological and seasonal patterns. Spearman's analysis indicated that there were significant correlations among the most important species (Planktothrix agardhii-rubescens group, Aphanizomenon flos-aquae and Dolichospermum planctonicum), nutrients and microcystins. We highlighted that the species composition during periods of maximum microcystin concentrations differed from those typically reported for other Mediterranean sites. We found new potential microcystin producers (Aphanizomenon klebahnii, Dolichospermum macrosporum and Dolichospermum viguieri), which emphasised the high diversity of cyanobacteria in the Mediterranean area and the need for detailed research at the local scale.
authors.affiliation: University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Mariani
authors.affiliation: University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy.
authors.forename: Bachisio Mario
authors.initials: BM
authors.lastname: Padedda
authors.affiliation: University of South Bohemia, Faculty of Science, Department of Botany, České Budějovice, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Kaštovský
authors.affiliation: Ente acque della Sardegna, Settore della limnologia degli invasi, Viale Elmas 116, 09122 Cagliari, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Buscarinu
authors.affiliation: University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Sechi
authors.affiliation: Ente acque della Sardegna, Settore della limnologia degli invasi, Viale Elmas 116, 09122 Cagliari, Italy.
authors.forename: Tomasa
authors.initials: T
authors.lastname: Virdis
authors.affiliation: University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Lugliè