Phytoplankton species succession in a shallow Mediterranean lake (L. Kastoria, Greece): steady-state dominance of Limnothrix redekei, Microcystis aeruginosa and Cylindrospermopsis raciborskii

Abstract

The phytoplankton species composition and seasonal succession were examined in Lake Kastoria during the period November 1998-October 1999. A total of 67 species and 19 functional groups were identified. Only 4 out of the 67 species, all Cyanobacteria, were dominant (Limnothrix redekei, Microcystis aeruginosa, Cylindrospermopsis raciborskii and Aphanizomenon gracile). Diatoms were rare, not only in terms of species number, but also in terms of biomass (contributing < 5% to the total phytoplankton biomass) in relation to the rather low silicon concentrations throughout the year. The functional groups S1, S N , M and H1 were found dominant in the lake. The species A. gracile (functional group H1) behaved like the species Cylindrospermopsis raciborskii(functional group S N ) which is tolerant to mixing and poor light conditions. The phytoplankton seasonal succession showed similar patterns in all six sampling stations, both at the surface and the bottom water layer, with minor differences during Microcystis aeruginosa dominance. Two steady-state phases were identified within a year lasting for 4 months under relatively stable physical conditions. In these steady-states, the Limnothrix redekei persistent dominance under low light availability and low inorganic nitrogen has been explained by its specific ability such as buoyancy regulation to exploit resources in the water column. Moreover, high population densities over the winter and before the development of daphnids may contribute to the steady-state dominance of Limnothrix. Different niches separated vertically in the water column is one of the explanations for the Limnothrix-Microcystis steady-state when a replacement between the two species was observed in different water layers and areas of the lake. Long lasting steady-states of Cyanobacteria observed in Lake Kastoria and in other Mediterranean and tropical freshwaters may indicate influence of warm climate properties on phytoplankton dynamics. Pediastrum boryanum (Turp.) Menegh. J P. duplex Meyen J P. simplex Meyen J P. tetras (Ehrenb.) Ralfs J Pseudodidymocystis fina (Kom.) Hege et Deason Scenedesmus acuminatus (Lagerh.) Chod. J Scenedesmus sp. J Selenastrum sp.

Comparison of Quantitative PCR and Droplet Digital PCR Multiplex Assays for Two Genera of Bloom-Forming Cyanobacteria, Cylindrospermopsis and Microcystis

“…Microcystis and Cylindrospermopsis are two of the most widespread and successful bloom-forming genera across continents (27,28). Many previous investigations have focused on a single dominant genus during bloom events.…”

“…Many previous investigations have focused on a single dominant genus during bloom events. However, cooccurrence of these genera has also been reported, with changes in dominance affected by nutrients, light, season, and grazing effects (28)(29)(30). The impacts of Microcystis and Cylindrosper- mopsis blooms are not restricted only to microcystins and cylindrospermopsins but have also recently extended to include compounds such as microsin, microviridin, and ␤-N-methylamino-Lalanine (BMAA), known to cause adverse ecological and health effects (31)(32)(33).…”

A comparative study of the impact of species composition on a freshwater phytoplankton community using two contrasting biotic indices

“…Many recent studies have analyzed dominant species displacement and replacement in algae bloom and non-bloom (Kuwata and Miyazaki, 2000;Hillmer et al, 2008), even niche theory implication in replacement between two dominant species in Lake Kastoria (Moustaka-Gouni et al, 2007), and rRNA genes technology implied in observing dominant phytoplankton succession (Newton et al, 2006). However, little research is focused on the effect of dominant species on changes in community composition and biodiversity in a stressed environment.…”

Growth inhibitory effect of Microcystis on Aphanizomenon flos-aquae isolated from cyanobacteria bloom in Lake Dianchi, China

“…The population dynamics of cyanobacteria bloom are often characterized by seasonal succession of dominant species (Messineo et al, 2010;Moustaka-Gouni et al, 2007;Tsukada et al, 2006). In China, this phenomenon of seasonal succession of dominant Severe eutrophication of freshwater ecosystem promotes frequent and long-lasting cyanobacteria blooms.…”