Publications (17) View all
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Article: Toxicity of Ammonia Nitrogen to Ciliated Protozoa Stentor coeruleus and Coleps hirtus Isolated from Activated Sludge of Wastewater Treatment Plants.
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ABSTRACT: We assessed the toxicity of ammonia ions to Stentor coeruleus and Coleps hirtus (Protozoa) isolated from activated sludge taken from two municipal wastewater treatment plants in southern Poland. Stentor coeruleus is a rarely occurring species in activated sludge, unlike the widespread Coleps hirtus. The mean LC50 values (concentration causing 50 % mortality) calculated for the 24 h tests differed hugely between the tested species: 43.03 mg NH(4+) dm(-3) for Stentor coeruleus and 441.12 mg NH(4+) dm(-3) for Coleps hirtus. The ammonia ion concentration apparently is an important factor in the occurrence of these protozoan species in activated sludge.Bulletin of Environmental Contamination and Toxicology 09/2012; 89(5):975-7. · 1.02 Impact Factor -
Article: The influence of temperature on the effectiveness of filamentous bacteria removal from activated sludge by rotifers.
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ABSTRACT: We investigated the feeding of the rotifer Lecane inermis on filamentous bacteria to determine if the ability of rotifers to remove filaments depends on temperature. The bacteria originated from two treatment plants, one of which was dominated by Microthrix parvicella and the other by Nostocoida limicola-like organisms. The experiments showed that the number of rotifers increased with temperature, and thus the ability of rotifers to reduce the number of filaments also increased with temperature. At 8 degrees C, their removal effectiveness was low, but the rotifers were able to survive at this temperature. When presented with sludge containing N. limicola-like microorganisms at 20 degrees C, the rotifers reduced the number of bacteria by 95%. In the case of M. parvicella, the reduction reached 50%. The results confirmed that Lecane are capable of controlling the growth of bacteria responsible for sludge bulking. This is the first report indicating that the seasonality of bulking may be the result of the activity of filamentous bacteria grazers, which is temperature dependent.Water Environment Research 08/2012; 84(8):619-25. · 0.88 Impact Factor -
Article: Dynamics of cyanobacteria-ciliate grazer activity in biotrophic and tritrophic microcosms.
Aquatic Microbial Ecology 01/2010; 59:45-53. · 2.39 Impact Factor -
Article: Resistance of nitrifiers inhabiting activated sludge to ciliate grazing.
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ABSTRACT: We monitored the succession of nitrifiers in a newly opened wastewater treatment plant for five weeks. After the first distinct decrease in total nitrogen, we began monitoring the appearance, size and number of nitrifying bacteria colonies using the fluorescence in situ hybridization (FISH) method. Ammonia oxidizing bacteria (AOB) colonies were visualized under green excitation as red, and nitrite oxidizing bacteria (NOB) colonies were visualized under blue excitation as green. The changes in protozoan community were monitored simultaneously. Ciliates were divided into four functional groups: predatory, bacterivorous free-swimming, bacterivorous crawling, and sessile. The results showed that at the time of the first distinct total nitrogen decrease, the mean length of both AOB and NOB were relatively low, but the colonies, especially those of nitrite oxidizers, were abundant. In time, the distribution of ammonia oxidizer colonies shifted towards larger sizes, but their quantity decreased. In the case of nitrite oxidizers, a similar trend was noticeable but less pronounced. These changes corresponded with an increasing number of crawling bacterivorous ciliates dominated by the "scavenger" genus Aspidisca. The increasing size of nitrifier colonies may have been due to the growing grazing pressure from crawling bacterivorous ciliates. The strong grazing pressure did not negatively affect N-NH(4)(+) removal effectiveness.Water Science & Technology 01/2010; 61(3):573-80. · 1.12 Impact Factor -
Article: Effects of grazers' species identity on cyanobacteria in bitrophic and tritrophic food webs.
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ABSTRACT: Using laboratory microcosms, we studied direct and indirect interactions among different components of bi- and tritrophic communities. Filamentous cyanobacteria (Phormidium sp.) and autotrophic flagellates (Chlorogonium elongatum) were primary producers. The second trophic level was represented by ciliates Furgasonia blochmanni and Pseudomicrothorax dubius grazing on the filamentous cyanobacteria and two filter feeders, Euplotes octocarinatus and Stylonychia pustulata, feeding on the autotrophic flagellates. An oligochaete, Chaetogaster sp., was used as the top predator. An experiment was carried out for all combinations of two factors: (1) the identity of the cyanobacteria consumer (Furgasonia or Pseudomicrothorax) and (2) the presence or absence of the top predator. Significant effects of the treatments on both the abundance of cyanobacteria and filter feeding ciliates and predator-induced defense in Phormidium and Euplotes were observed in a 36-day experiment. The experiment showed that the substitution of one species (Furgasonia) for another (Pseudomicrothorax) seemingly playing the same ecological role may lead to significant changes in the whole community.FEMS Microbiology Ecology 05/2009; 68(3):329-39. · 3.41 Impact Factor
