Magdalena Toporowska

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.

Simultaneous accumulation of anatoxin-a and microcystins in three fish species indigenous to lakes affected by cyanobacterial blooms

A four-year study carried out in a lake with perennial water blooms caused by toxigenic Planktothrix agardhii (Oscillatoriales) and Anabaena lemmermanii, Anabaena flos-aquae, Anabaena spp. and Aphanizomenon issatchenkoi (Nostocales) revealed that the lake-dwelling fish were threatened by simultaneous exposure to intracellular and extracellular microcystins (MCs) as well as anatoxin-a (ANTX). Higher contents of anatoxin-a and microcystins were found in livers than in fish muscles. This is the first report on ANTX accumulation in the common fish, indigenous to European freshwaters during perennial cyanobacterial blooms. Generally, the omnivorous roach (Rutilus rutilus) and Prussian carp (Carassius gibelio) accumulated higher amounts of MCs in their tissues compared to mostly predacious perch (Perca fluviatilis), and similar amounts of ANTX. The long-lasting presence of MCs exceeding the safe levels for consumption was found in fish muscles. ANTX accumulation in fish muscles (up to 30 ng g−1 FW) suggests the probability of its transfer in a food chain.

Blooms of toxin-producing Cyanobacteria — a real threat in small dam reservoirs at the beginning of their operation

Large and harmful cyanobacterial blooms appeared in two newly-built artificial reservoirs shortly after being filled with water. Taxonomic composition of cyanobacterial communities was highly variable in both water bodies and fast species replacement was observed. In the first year of the operation of the smaller Konstantynów Reservoir, the mass development of Anabaena flos-aquae and Planktolyngbya limnetica (48.7 and 53.6% of the cyanobacterial abundance) occurred in summer, while in autumn the dominance of Planktothrix agardhii (99.9%, 14.95 × 106 ind. Dm−3) was noted. The surface scum developed in summer consisted of An. flos-aquae that contained high amounts of anatoxin-a (1412.4 μg AN-a dm−3 of scum) and smaller amounts of microcystins (10 μg eq. MC-LR dm−3 of scum). In the larger Kraśnik Reservoir, Aphanizomenon flos-aquae occurred in high abundance in spring and summer, however, it was replaced by different species of Microcystis (1.3 × 107 ind. dm−3) which created thick surface scum. Simultaneously, a hazardous increase in the total concentration of microcystins (from 13.6 to 788.5 μg eq. MC-LR dm−3 of water with scum) and anatoxin-a (from 0.03 to 43.6 μg dm−3) was observed.

Epiphytic algae on Stratiotes aloides L., Potamogeton lucens L., Ceratophyllum demersum L. and Chara spp. in a macrophyte-dominated lake.

Epiphytic algae on Stratiotes aloides L., Potamogeton lucens L., Ceratophyllum demersum L. and Chara spp. in a macrophyte-dominated lake Epiphytic algae occurring on submerged macrophytes were investigated as part of a study on the ecological status of a shallow macrophyte-dominated lake, Lake Skomielno, which has been used for recreation and fishery. Relatively high variability in biomass (DM) and chlorophyll a contents in epiphyton on particular plants was noted. Generally, the biomass of epiphytic algae was much higher in spring and autumn than in summer. In total, 335 taxa were found on the studied macrophytes with representatives of the Chlorophyta (143 taxa) and Heterokontophyta class Bacillariophyceae (131 taxa) dominating. The species composition of epiphytic algae was related to host plant and seasons, the highest species richness was observed on Stratiotes aloides in spring and on Potamogeton lucens in autumn. The Jaccard similarity index revealed differentiation of diatom communities between the macrophytes. Our data suggest that in the studied lake S. aloides and P. lucens can provide better habitat conditions for higher numbers of epiphytic taxa, abundances and epiphyton standing crop than Ceratophyllum demersum and Chara spp. can. The dominance of diatom species (e.g. Pseudostaurosira brevistriata (Grun.) Williams & Round, Achnanthidium minutissimum (Kütz.) Czarnecki, and Cocconeis placentula Ehrenb.) that are known as bioindicators of slightly alkaline, sufficiently oxygen-saturated and meso-eutrophic waters corresponds well with the physico-chemical parameters of Lake Skomielno.

The biodegradation of microcystins in temperate freshwater bodies with previous cyanobacterial history

Cyanobacterial blooms and cyanotoxins occur in freshwater lakes and reservoirs all over the world. Bacterial degradation of microcystins (MC), hepatotoxins produced by several cyanobacterial species, has also been broadly documented. However, information regarding MC biodegradation in European water bodies is very limited. In this paper, the occurrence and identification of MC biodegradation products was documented for 21 European lakes and reservoirs, many of which have well-documented cyanobacterial bloom histories. Varying cyanobacterial abundance and taxonomical composition were documented and MC producers were found in all the analysed samples. Planktothrix agardhii was the most common cyanobacterial species and it formed mass occurrences in four lakes. MC biodegradation was observed in 86% of the samples (18 out of 21), and four products of dmMC-LR decomposition were detected by HPLC and LC-MS methods. The two main products were cyclic dmMC-LR with modifications in the Arg-Asp-Leu region; additionally one product was recognized as the tetrapeptide Adda-Glu-Mdha-Ala. The composition of the detected products suggested a new biochemical pathway of MC degradation. The results confirmed the hypothesis that microcystin biodegradation is a common phenomenon in central European waters and that it may occur by a mechanism which is different from the one previously reported. Such a finding implies the necessity to develop a more accurate methodology for screening bacteria with MC biodegradation ability. Furthermore, it warrants new basic and applied studies on the characterization and utilization of new MC-degrading strains and biodegradation pathways.

Impact of lake-catchment processes on phytoplankton community structure in temperate shallow lakes: Impact of lake-catchment processes on phytoplankton

Department of Hydrobiology and Protection of Ecosystems, University of Life Sciences in Lublin, Lublin, Poland Department of Hydrology, Maria Curie‐ Skłodowska University in Lublin, Lublin, Poland Correspondence Magdalena Toporowska, Department of Hydrobiology and Protection of Ecosystems, University of Life Sciences in Lublin, Akademicka 13, Lublin 20‐950, Poland. Email: magdalena.toporowska@up.lublin.pl Funding information National Science Centre (NCN), Grant/Award Number: 2015/17/D/ST10/02105