Aleksandra Pełechata

Cyanobacteria and cyanotoxins in Polish freshwater bodies

In this work, the authors examined the presence of cyanobacteria and cyanotoxins in 21 samples collected from fresh water bodies located in 5 provinces in Poland: Lublin (2), Podlasie (1), Pomerania (6), Warmia-Masuria (1) and Wielkopolska (11). In addition, to determine the general pattern of geographical distribution, frequency of cyanobacteria occurrence, and cyanotoxins production, the published data from 238 fresh water bodies in Poland were reviewed. On the basis of these collected results, we concluded that Planktothrix, Aphanizomenon, Microcystis and Dolichospermum were dominant. The general pattern in geographical distribution of the identified cyanobacterial genera was typical of other eutrophic waters in Europe. The production of cyanotoxins was revealed in 18 (86%) of the 21 samples analyzed in the present work and in 74 (75%) of the 98 total water bodies for which the presence of toxins had been examined. Among the 24 detected microcystin variants, [Asp3]MC-RR was most common. These results can be verified when more data from the less explored water bodies in the southern and eastern parts of Poland are available.

The in situ influence of Ceratophyllum demersum on a phytoplankton assemblage

The in situ influence of Ceratophyllum demersum on a phytoplankton assemblage The aim of this work was to present a quantitative and qualitative analysis of a phytoplankton assemblage under the influence of Ceratophyllum demersum L. during a two-year field study. Literature data obtained under laboratory conditions indicate that C. demersum may cause a decrease in the blue-green algae biomass, which is considered to be evidence of the significance of allelopathy. The observations reported in the current paper indicated that there was no clear effect on cyanoprokaryota whereas decreases in the quantity of Cryptophyta, Dinophyta, Chlorophyta, and Chrysophyceae are noted.

Interrelationships between macrophytes (including charophytes) and phytoplankton and the ecological state of lakes

Abstract Multidisciplinary investigations of 30 lakes (mid-Western Poland) were carried out in the years 2001–2004. Micro- and macrophyte vegetation was studied against the background of abiotic conditions. Significantly higher biomass of phytoplankton was found in nutrient rich shallow lakes without both charophyte and vascular submersed vegetation as well as in lakes with only poorly developed vascular communities. Visibly better abiotic conditions and the lowest phytoplankton biomass were observed in deeper lakes with diverse macrophyte (and particularly charophyte) vegetation. Lakes with poorly developed charophyte vegetation represented transitional conditions and biomass. Nevertheless, in some (mostly shallow) lakes, where submersed vegetation and particularly charophyte communities were well developed, phytoplankton biomass was rather low and the transparency was high despite eutrophic conditions. Additionally, in those lakes macrophyte vegetation was not only abundant but also diverse with rare, valuable or even unexpected communities of high bioindicator value. Interestingly, an opposing situation with abundant phytoplankton and bad light conditions was also documented in shallow lakes with submersed vegetation. In those lakes, however, only vascular macrophytes developed dense but homogeneous (monospecific) beds. The results are discussed regarding interrelationships between macrophyte vegetation and phytoplankton assemblages.