Magdalena Grabowska

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 effect of cyanobacterial blooms in the Siemianówka Dam Reservoir on the phytoplankton structure in the Narew River

The effect of cyanobacterial blooms on the phytoplankton structure in the lowland Narew River (north-eastern Poland) was examined. The studies were carried out at stations situated at different distances from the eutrophic Siemianówka Dam Reservoir. In 2008, the investigated lowland reservoir and the outflowing river were characterized by the dominance of toxic cyanobacteria (from July to October). At a station situated 130 km below the dam, species composition in the river was very similar to that in the shallow reservoir. Planktothrix agardhii was the main and permanent dominant, both in limnoplankton and potamoplankton. The current study indicates that the eutrophic Siemianówka Dam Reservoir is the main and rich source of phytoplankton for the outflowing Narew River. Cyanobacteria were dominant in the river phytoplankton at all sampling stations, but their share in phytoplankton biomass gradually decreased with the distance from the dam. Chemical analysis revealed the presence of microcystins (MCs) in water samples collected from June to October. The toxins, mainly demethylated MC analogues, were detected at a long distance down the river, even 100 km from the dam. Maximum concentration of MCs (14.3 μg l−1) was measured on 13 October, 9.1 km below the dam.

Replacement of Chroococcales and Nostocales by Oscillatoriales caused a significant increase in microcystin concentrations in a dam reservoir

Replacement of chroococcales and nostocales by oscillatoriales caused a significant increase in microcystin concentrations in a dam reservoir A two-year study on cyanobacterial development and the dynamics of intracellular microcystins was carried out in a shallow dam reservoir. Potentially toxic cyanobacteria (Microcystis wesenbergii, M. aeruginosa, Woronichinia naegeliana, Anabaena spp., Planktothrix agardhii) were observed to be the main component (70-94% total biomass) of the phytoplankton community, in which species composition was unstable and was very different between the 2005 and 2006 summer seasons. Generally, total phytoplankton, cyanobacterial biomass and total microcystin (MC) concentrations in the reservoir were much higher in 2006 than in 2005. The highest MC concentration (173.8 μg MC-LR equivalent dm-3) was seen in 2006 during P. agardhii (Oscillatoriales) domination (max. fresh biomass 50.3 mg dm-3; above 91% of phytoplankton biomass). Positive correlations between microcystin concentrations and cyanobacterial biomass suggest that populations of Nostocales and Oscillatoriales in 2005 and Oscillatoriales (P. agardhii) in 2006 may have been the main producers of MCs in the reservoir. The strong increase in P. agardhii biomass concomitant with a decrease in the total biomass of Chroococcales and Nostocales was responsible for the increase in MC concentration in the Siemianówka dam reservoir.

Ecological status of shallow Lake Gorbacz (NE Poland) in its final stage before drying up

The article assesses the ecological status of shallow Gorbacz Lake (NE Poland) in the last stage before complete drying up. For last few years hydrological regime of the lake catchment has been changed dramatically which was caused by functioning nearby peat mine and longer autumn drought periods for following years. Progressing macrophytes succession leaded complete emergent macrophytes overgrowth of the lake beginning from 2000. The analyses include records of previous samples and data for morphology, water quality, phytoplankton, zooplankton and macrophytes. The trophic status of Gorbacz Lake was verified compare to the previous studies. The results indicate that even with minimum amount of water Gorbacz Lake itself still keeps its dystrophic character with increasing of water color and of DOC, biogenic substances, chlorophyll a concentrations. Humic State Index (HSI) and hydrochemical dystrophy index (HDI) confirm the dystrophic status of the lake with values 71.3 and 76.2 respectively. Both typical phytoplankton representatives of eutrophic and dystrophic waters were recorded. Very high diversity of desmids in the telmatoplankton, indicates the observed process of shallowing in the reservoir. Planktonic crustacean fauna was represented by small filtrators. Rotifera community was strongly dominated by Trichocerca simonei. The article concludes with the main causes of the observed changes and some future remarks for the lake state.

Non-ribosomal peptides produced by Planktothrix agardhii from Siemianówka Dam Reservoir SDR (northeast Poland)

Planktothtrix agardhii (Oscillatoriales) is a filamentous cyanobacterium, which frequently forms blooms in shallow, polymictic and eutrophicated waters. This species is also a rich source of unique linear and cyclic peptides. In the current study, the profile of the peptides in samples from the P. agardhii-dominated Siemianówka Dam Reservoir (SDR) (northeast Poland) was analyzed for four subsequent years (2009–2012). The LC–MS/MS analyses revealed the presence of 33 peptides. Twelve of the most abundant ones, including five microcystins, five anabaenopeptins, one aeruginosin and one planktocyclin, were present in all field samples collected during the study. The detection of different peptides in two P. agardhii isolates indicated that the SDR population was composed of several chemotypes, characterized by different peptide patterns. The total concentration of microcystins (MCs) positively correlated with the biomass of P. agardhii. Between subsequent years, the changes in the ratio of the total MCs concentration to the biomass of P. agardhii were noticed, but they were less than threefold. This is the first study on the production of different classes of non-ribosomal peptides by freshwater cyanobacteria in Poland.

Long-term variations of phytoplankton primary production in a shallow, polyhumic reservoir

Multiannual and seasonal variation of phytoplankton primary production parameters were investigated in a polymictic, polyhumic dam reservoir. High values of the gross production indicate increasing eutrophication of reservoir waters already from the first years of its existence. The predominance of the total respiration over the net production is caused by substantial natural loads of dissolved organic matter fed to the reservoir from the peaty-forest catchment.

Effects of lateral connectivity on zooplankton community structure in floodplain lakes

Hydrological conditions are responsible for the changes in lateral connectivity between the main river channel and the floodplain lakes, a factor controlling zooplankton abundance and diversity. We tested the hypothesis that the degree of connectivity between the aquatic habitats and the river channel governs the zooplankton densities and community structure. Abundances, community composition and species diversity of zooplankton were analysed against the gradient of lakes’ connectivity and the water quality parameters under a natural flood pulse in the Biebrza River (North-Eastern Poland). Our findings revealed that the water level fluctuations directly affect the availability of nutrients, aeration, what in turn controls the densities and biovolumes of zooplankton communities. Along with the increase in the lake isolation, the taxonomic diversity of zooplankton decreased, while the eudomination of taxa indicative of advanced trophy (Rotifera) was observed. Qualitative parameters, as number of species, diversity and richness, were significantly higher at mean water levels, which supports the intermediate disturbance hypothesis. The sensitivity of the zooplankton community to variable hydrological conditions and lateral connectivity gradient demonstrates its potential as an unexploited indicator of any habitat changes in the aquatic ecosystems.

Vertical distribution of cyanobacteria biomass and cyanotoxin production in the polymictic Siemianówka Dam Reservoir (eastern Poland)

Abstract The summer-autumn dominance of the toxic cyanobacterium Planktothrix agardhii was described in the lowland polymictic Siemianowka Dam Reservoir (SDR) in 2010 and 2011. The study was conducted at a station located in the deepest part of the reservoir. The species composition of phytoplankton was very similar at the four depths analyzed. Microcystins were continually present in the cyanobacterial biomass. Demethylated microcystin-RR (dmMC-RR) and microcystin-RR (MC-RR) were identified as the major microcystin variants in most samples, while demethylated microcystin-LR (dmMC-LR) and microcystin-LR (MC-LR) were each recorded only once. The concentration of microcystin-RR correlated strongly with the biomass of P. agardhii. The effect of environmental factors on cyanobacterial biomass the production of microcystins by cyanobacteria was minor, but increased water temperatures and pH favored the production of microcystins. Phytoplankton biomass was also influenced by how water outflow from the reservoir was regulated; the biomas increased with depth when the upper flaps were opened, but it was very similar throughout the water column when they were closed. According to the Polish phytoplankton-based index (IFPL), the ecological potential of the reservoir was determined to be poor.

Summer phytoplankton in selected lakes of the East Suwałki Lakeland in relation to the chemical water parameters

Abstract The study covered a complex of 16 lakes of the East Suwałki Lakeland, distinguished by high differentiation of morphometric parameters determining their polymictic or dimictic character. In half of the lakes studied, the occurrence of summer water thermal stratification was observed. It strongly influenced the vertical qualitative and quantitative diversification of phytoplankton. The majority of the lakes studied were classified as eutrophic waters. Only lakes Szelment Wielki and Pejcze had the Carlson chlorophyll index at the boundary of mesoeutrophy. In the case of the majority of the lakes, the concordance of all the trophy indices was recorded. In 6 mesoeutrophic lakes, the character of water was only suggested by phytoplankton parameters

Autotrophic and heterotrophic plankton under ice in a eutrophic temperate lake

Abstract Ice cover can considerably influence the food web structure and dynamics of lake ecosystems during winter. The aim of this study was to test the hypothesis that, due to unfavourable conditions, abundances of planktonic organisms are low under ice. The components of the microbial loop (nanoflagellates, ciliates) and the classical food web (algae, rotifers, crustaceans) were investigated in a eutrophic lake from January to April, at 7-day intervals. The phytoplankton was dominated by the mixotrophic chrysophyte Synura uvella, which formed an intense phytoplankton bloom. Nanoflagellates (mostly heterotrophic forms) and ciliates (oligotrichs, prostomatids) were present in relatively high numbers. Rotifers were represented by the algivorous taxa (Notholca squamula, Polyarthra dolichoptera) and reached surprisingly high abundances. There were no significant correlations between physical parameters and protists, but correlations were apparent between the thickness of the ice and the numbers of cyanobacteria, diatoms (negative) and chrysophytes (positive). The absence of crustaceans and relationships between rotifers and both algae and nanoflagellates indicate that these groups were probably a crucial factor determining the abundance and composition of the rotifer community. These results suggest that the microbial loop had a central role in the functioning of the ecosystem under ice in this eutrophic lake.