Beata Klimek

The use of rotifers for limiting filamentous bacteria Type 021N, a bacteria causing activated sludge bulking

The excessive growth of filamentous bacteria and the resultant bulking of activated sludge constitute a serious problem in numerous wastewater treatment plants. Lecane inermis rotifers were previously shown to be capable of reducing the abundance of Microthrix parvicella and Nostocoida limicola in activated sludge. In the present study, the effectiveness of four Lecane clones in reducing the abundance of Type 021N filamentous bacteria was investigated. Three independent experiments were carried out on activated sludge from three different treatment plants. We found that Lecane rotifers are efficient consumers of Type 021N filaments.

Model-based experimental design for assessing effects of mixtures of chemicals

We exposed flour beetles (Tribolium castaneum) to a mixture of four poly aromatic hydrocarbons (PAHs). The experimental setup was chosen such that the emphasis was on assessing partial effects. We interpreted the effects of the mixture by a process-based model, with a threshold concentration for effects on survival. The behavior of the threshold concentration was one of the key features of this research. We showed that the threshold concentration is shared by toxicants with the same mode of action, which gives a mechanistic explanation for the observation that toxic effects in mixtures may occur in concentration ranges where the individual components do not show effects. Our approach gives reliable predictions of partial effects on survival and allows for a reduction of experimental effort in assessing effects of mixtures, extrapolations to other mixtures, other points in time, or in a wider perspective to other organisms.

Composition and activity of soil microbial communities in different types of temperate forests

The composition and diversity of forest soil microbial communities may be affected by the composition of plant communities and characteristics of soils. The objective of our study was to compare microbial properties of soils under various types of temperate forests. The samples were taken from soil A horizons under dry and mesic pine forests, acidophilus and fertile beech forests, hornbeam and oak dominated deciduous forests and ash dominated riparian forest. The samples were analysed for pH and the contents of organic C and total N, P, K, Ca, Mg and Mn. Microbial analyses included determination of microbial biomass, basal respiration, community level physiological profiles (CLPPs) measured by MicroResp™ method and phospholipid fatty acid (PLFA) profiles. The soil microbial communities under the pine forests were lower, less active and exhibited different CLPPs and PLFA profiles than those under deciduous forests. The PLFA profiles and CLPPs were correlated to each other revealing that the observed different metabolic abilities under the pine and deciduous forest types resulted from differences in taxonomic composition of soil microbial communities. The CLPPs and PLFA profiles depended on soil texture and the contents of Corg, Nt, and Pt indicating that in the temperate forests the taxonomic and functional composition of soil microbial communities are shaped by both the soil properties and the vegetation. The functional diversity of soil microbial communities was not related to plant diversity indicating that in temperate forests the number of plant species has little effect on the ability of soil microorganisms to degrade different organic compounds.

Trace element concentrations in lichens collected in the Beskidy Mountains, the Outer Western Carpathians.

Abstract The aim of the study was to assess trace metal air pollution in the Beskidy Mountains, the Outer Western Carpathians, Poland, with a widely used bioaccumulating organism, a lichen, Hypogymnia physodes. Lichens were collected at five stands (mountains) in parallel transect and analyzed for cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) content. Concentrations of Cd, Pb and Zn in lichens were elevated, indicating moderate air pollution. The studied sites grouped in two clusters, with the three more contaminated sites being at the west end of the transect, and the two less polluted sites being situated more eastward. Such a pattern can be explained by the location of industrial centers and prevailing wind direction in southern Poland. The strongest correlation was noticed between Zn and Pb, which are known to occur jointly in ore deposits and are being processed in nearby Polish and Czech industrial regions.

The Effects of Heavy Metals and Total Petroleum Hydrocarbons on Soil Bacterial Activity and Functional Diversity in the Upper Silesia Industrial Region (Poland)

Various inorganic and organic pollutants in industrial soils may adversely affect soil microorganisms and terrestrial ecosystem functioning. The aim of the study was to explore the relationship between the microbial activity, microbial biomass, and functional diversity of soil bacteria and the metals and total petroleum hydrocarbons (TPHs) in the Upper Silesian Industrial Region (Poland). We collected soil samples in pine-dominated forest stands and analyzed them according to a range of soil physicochemical properties, including metal content (cadmium, lead, and zinc) and TPH content. Metal concentrations were normalized to their toxicity to soil microorganisms and integrated in a toxicity index (TI). Soil microbial activity measured as soil respiration rate, microbial biomass measured as substrate-induced respiration rate, and the bacterial catabolic activity (area under the curve, AUC) assessed using Biolog® ECO plates were negatively related to TPH pollution as shown in multiple regressions. The canonical correspondence analysis (CCA) showed that both TPH and TI affected the community-level physiological profiles (CLPPs) of soil bacteria and the pollutants’ effects were much stronger than the effects of other soil properties, including nutrient content.

The Toxicity of Aluminium Salts to Lecane Inermis Rotifers: Are Chemical and Biological Methods Used to Overcome Activated Sludge Bulking Mutually Exclusive?

Abstract The aim of this study was to assess the effects of two flocculants that are often used to overcome activated sludge bulking problems - aluminium chloride, AlCl3, and aluminium sulphate, Al2(SO4)3 - on Lecaneinermis (Rotifera, Monogononta) at three different temperatures: 8, 15 and 20°C. The mean EC50 value (effective concentration, mg dm-3) calculated for the 24 h mortality test was 0.012 mg Al3+dm-3. Next, the effects of low concentrations of the Al-salts on the population development from single individuals (parthenogenetic females) were tested in a 21-day experiment. At concentrations as low as EC4.8 and EC0.48, both Al-salts affected rotifer population negatively. However, temperature was the most pronounced factor that modified the toxicity of the Al-salts to the rotifers. On the 12th day of the experiment, there were significant interactions between temperature and the Al-salts, indicating that the chemicals were more toxic to the rotifers at 20°C than at lower temperatures. The weaker rotifers sensitivity to Al-salts (especially to AlCl3) in temperatures below 15°C, when the biggest problems associated with sludge bulking occurs,may means use both rotifers and chemicals reasonable and effective. Streszczenie Sole glinu są powszechnie stosowanym fl okulantem, służącym zwalczaniu puchnięcia osadu czynnego w biologicznych oczyszczalniach ścieków. Nowa idea biologicznego zwalczania tego niekorzystnego dla prawidłowej pracy oczyszczalni zjawiska polega na zastosowaniu wrotków z gatunku z Lecaneinermis. Wrotki te naturalnie występują w osadzie czynnym i są w stanie zjadać bakterie nitkowate, jak Microthrixparvicella, sprawiające najwięcej problemów w eksploatacji oczyszczalni podczas miesięcy zimowych. Celem badań było porównanie toksyczności chlorku glinu AlCl3 oraz siarczanu glinu Al2(SO4)3 dla wrotków Lecaneinermis w trzech temperaturach: 8, 15 and 20°C. Średnią wartość EC50 (stężenie powodujące 50% efekt, mg dm-3) dla śmiertelności wrotków na podstawie 24-godzinnego testu ustalono na poziomie 0.012 mg Al3+ dm-3. Następnie, badano wpływ niskich stężeń soli glinu na tempo wzrostu populacji z pojedynczego osobnika (partenogenetyczna samica) w 21-dniowym eksperymencie. Ustalono, że stężenia na poziomie odpowiadającym EC4.8, a nawet EC0.48 wpływają negatywnie na tempo wzrostu populacji. Temperatura silnie wpływała na toksyczność glinu. W 12-tym dniu eksperymentu stwierdzono, że zachodzi istotna interakcja pomiędzy toksycznością glinu i temperaturą, wskazująca, że w 20°C glin jest bardziej toksyczny dla wrotków niż w niższych badanych temperaturach. Mniejsza wrażliwość wrotków na glin w temperaturze poniżej 15°C może oznaczać, że łączenie tych dwóch metod zwalczania puchnięcia osadu czynnego w miesiącach zimowych może być racjonalnym i efektywnym rozwiązaniem.

The relationship between soil bacteria substrate utilisation patterns and the vegetation structure in temperate forests

The aim of the study was to explore the relationship between the functional diversity pattern of soil bacteria and the vegetation diversity and structure in temperate forests (Poland). Pine-dominated forests occur on soils with lower pH, fewer nutrient contents (P, Na, Mg, Mn and K) and higher C/N and C/P ratios than beech-dominated forests and mixed broadleaved forest with hornbeam and ash. Both forest type and soil horizon (O and A) strongly influenced bacterial catabolic activity and the number of substrates decayed on Biolog® ECO plates. Pine forest soil bacteria were less active and less functionally diverse than those in deciduous forest soils. The community-level physiological profiles (CLPPs) were dissimilar (one-way analysis of similarities) between pine and mixed deciduous forests, but only in the O soil horizon. Carboxylic acids primarily contributed to the average dissimilarity in CLPP between forests (the similarity percentage procedure); these substrates are preferentially used by pine forest soil bacteria. The canonical correspondence analysis indicated that soil pH, nitrogen and organic matter contents and plant diversity index

Functional diversity of soil microbial communities in boreal and temperate Scots pine forests

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