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The aim of the study was to determine the species composition and dynamics of the phytoplankton community of Koprinka reservoir. We have identified a total of 109 taxa assigned to 6 divisions including Chlorophyta (37), Ochrophyta (26), Cyanoprokaryota (22), Euglenophyta (11), Streptophyta (11) and Pyrrhophyta (2). The highest phytoplankton biomass (PhB) and numbers (PhN) and the lowest species richness were detected in September. In October with the decrease of the PhB the species diversity has increased. The highest species richness was observed at station 3, situated in the riverine area, with the phytoplankton abundance being significantly higher compared to the other two stations. The species Hariotina polychorda dominated in the water samples in the summer at all stations. In the early autumn, a bloom of the potentially toxic species Microcystis wesenbergii was detected, which is an indicator for eutrophication process in the reservoir. Cluster analysis (CA) based on the phytoplankton composition isolated the samples from each sampling periods in a separate water cluster, characterized by significant spatial heterogeneity. The phytoplankton species composition, and the values for biomass, and chlorophyll a are evident for the eutrophic state of the reservoir.

The aim of the study was to determine the species composition and dynamics of the phytoplankton community of Koprinka reservoir. We have identified a total of 109 taxa assigned to 6 divisions including Chlorophyta (37), Ochrophyta (26), Cyanoprokaryota (22), Euglenophyta (11), Streptophyta (11) and Pyrrhophyta (2). The highest phytoplankton biomass (PhB) and numbers (PhN) and the lowest species richness were detected in September. In October with the decrease of the PhB the species diversity has increased. The highest species richness was observed at station 3, situated in the riverine area, with the phytoplankton abundance being significantly higher compared to the other two stations. The species Hariotina polychorda (Korshikov) E.Hegewald dominated in the water samples in the summer at all stations. In the early autumn, a bloom of the potentially toxic species Microcystis wesenbergii (Komárek) Komárek ex Komárek was detected, which is an indicator for eutrophication process in the reservoir. Cluster analysis (CA) based on the phytoplankton composition isolated the samples from each sampling periods in a separate water cluster, characterized by significant spatial heterogeneity. The phytoplankton species composition, and the values for biomass, and chlorophyll a are evident for the eutrophic state of the reservoir. [ABSTRACT FROM AUTHOR]

Between September 2011 and October 2012, 13 samplings at 8 stations in the Riogrande II Reservoir (Colombia) were undertaken. It is located in a high-mountainous tropical (75°32'30'' W - 75°26'10'' W and 6°33'50'' N - 6º28'07''N), which supplies water to a plant treatment for public supply and to a small hydroelectric plant. The basins of the two main tributaries of the reservoir are highly impacted by human activity. We report the presence of a Dolichospermum lemmermannii, which up to now has only been registered as a temperate and high latitude species. Also the general ecology of the species is established, such as, generation and renewal times, spatial and temporal patterns, and interaction with more important environmental variables. [ABSTRACT FROM AUTHOR]

The population dynamics of potentially harmful phytoplankton in the semi-closed, coastal Bizerte Lagoon, Tunisia, in the south-western Mediterranean, were examined from November 2007 to February 2009 at six sampling stations, three situated in areas of mussel and oyster farming. The harmful species monitored included the potential producers of amnesic shellfish poisoning (Pseudo-nitzschiaspp.), paralytic shellfish poisoning (Alexandriumspp.), diarrheic shellfish poisoning (Dinophysisspp. andProrocentrumspp.), ichthyotoxins (Cochlodinium polykrikoides,Akashiwo sanguineaandKarenia mikimotoi), yessotoxins (Gonyaulax spinifera) and the discolouration of water (Neoceratium lineatumandProtoperidiniumsp.). These were numerically dominated by potentially toxic species of the diatom genusPseudo-nitzschia, which were present year-round at all stations.Prorocentrumspp.,Dinophysisspp. andNeoceratium lineatumwere the most abundant and recurrent harmful dinoflagellates, exhibiting their highest densities at the shellfish farming stations.Alexandriumspp. bloomed only on one occasion, reaching its highest densities at a shellfish farming station. Canonical correspondence analyses revealed significant relationships between the harmful phytoplankton species monitored and the environmental conditions. The widespread distribution of harmful phytoplankton in Bizerte Lagoon, with the permanent presence ofPseudo-nitzschiaspp. and the high frequency of dinoflagellate blooms in the shellfish areas, suggests a potential risk of shellfish poisoning events in the region. [ABSTRACT FROM AUTHOR]