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  • 1.
    Attermeyer, Katrin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Andersson, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Catalán, Núria
    Catalan Institute for Water Research (ICRA), Girona, Spain.
    Einarsdóttir, Karólina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Groeneveld, Marloes M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Potential terrestrial influence on transparent exopolymer particle (TEP) concentrations in boreal freshwaters2019In: Journal of limnology, ISSN 1129-5767, E-ISSN 1723-8633, Vol. 64, no 6, p. 2455-2466Article in journal (Refereed)
    Abstract [en]

    Transparent exopolymer particles (TEP) are ubiquitous in aquatic ecosystems and contribute, for example, to sedimentation of organic matter in oceans and freshwaters. Earlier studies indicate that the formation of TEP is related to the in situ activity of phytoplankton or bacteria. However, terrestrial sources of TEP and TEP precursors are usually not considered. We investigated TEP concentration and its driving factors in boreal freshwaters, hypoth- esizing that TEP and TEP precursors can enter freshwaters via terrestrial inputs. In a field survey, we measured TEP concentrations and other environmental factors across 30 aquatic ecosystems in Sweden. In a mesocosm experi- ment, we further investigated TEP dynamics over time after manipulating terrestrial organic matter input and light conditions. The TEP concentrations in boreal freshwaters ranged from 83 to 4940 μg Gum Xanthan equivalent L−1, which is comparable to other studies in freshwaters. The carbon fraction in TEP in the sampled boreal freshwaters is much higher than the phytoplanktonic carbon, in contrast to previous studies in northern temperate and Medi- terranean regions. Boreal TEP concentrations were mostly related to particulate organic carbon, dissolved organic carbon, and optical indices of terrestrial influence but less influenced by bacterial abundance, bacterial production, and chlorophyll a. Hence, our results do not support a major role of the phytoplankton community or aquatic bac- teria on TEP concentrations and dynamics. This suggests a strong external control of TEP concentrations in boreal freshwaters, which can in turn affect particle dynamics and sedimentation in the recipient aquatic ecosystem.

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  • 2.
    Berga, Mercè
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Yinghua, Zha
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Székely, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Testing responses of bacterial communities to environmental change using whole ecosystem manipulation experimentsManuscript (preprint) (Other academic)
  • 3.
    Berga, Mercè
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde, Germany.
    Zha, Yinghua
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Functional and Compositional Stability of Bacterial Metacommunities in Response to Salinity Changes2017In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 8, article id 948Article in journal (Refereed)
    Abstract [en]

    Disturbances and environmental change are important factors determining the diversity,composition, and functioning of communities. However, knowledge about how naturalbacterial communities are affected by such perturbations is still sparse. We performeda whole ecosystem manipulation experiment with freshwater rock pools where weapplied salinity disturbances of different intensities. The aim was to test how thecompositional and functional resistance and resilience of bacterial communities,alpha- and beta-diversity and the relative importance of stochastic and deterministiccommunity assembly processes changed along a disturbance intensity gradient.We found that bacterial communities were functionally resistant to all salinity levels (3, 6, and 12 psu) and compositionally resistant to a salinity increase to 3 psu andresilient to increases of 6 and 12 psu. Increasing salinities had no effect on local richnessand evenness, beta-diversity and the proportion of deterministically vs. stochasticallyassembled communities. Our results show a high functional and compositional stabilityof bacterial communities to salinity changes of different intensities both at localand regional scales, which possibly reflects long-term adaptation to environmentalconditions in the study system.

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  • 4.
    Berga, Mercé
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Effects of Disturbance Intensity and Frequency on Bacterial Community Composition and Function2012In: PLOS ONE, E-ISSN 1932-6203, Vol. 7, no 5, p. e36959-Article in journal (Refereed)
    Abstract [en]

    Disturbances influence community structure and ecosystem functioning. Bacteria are key players in ecosystems and it is therefore crucial to understand the effect of disturbances on bacterial communities and how they respond to them, both compositionally and functionally. The main aim of this study was to test the effect of differences in disturbance strength on bacterial communities. For this, we implemented two independent short-term experiments with dialysis bags containing natural bacterial communities, which were transplanted between ambient and 'disturbed' incubation tanks, manipulating either the intensity or the frequency of a salinity disturbance. We followed changes in community composition by terminal restriction fragment analysis (T-RFLP) and measured various community functions (bacterial production, carbon substrate utilization profiles and rates) directly after and after a short period of recovery under ambient conditions. Increases in disturbance strength resulted in gradually stronger changes in bacterial community composition and functions. In the disturbance intensity experiment, the sensitivity to the disturbance and the ability of recovery differed between different functions. In the disturbance frequency experiment, effects on the different functions were more consistent and recovery was not observed. Moreover, in case of the intensity experiment, there was also a time lag in the responses of community composition and functions, with functional responses being faster than compositional ones. To summarize, our study shows that disturbance strength has the potential to change the functional performance and composition of bacterial communities. It further highlights that the overall effects, rates of recovery and the degree of congruence in the response patterns of community composition and functioning along disturbance gradients depend on the type of function and the character of the disturbance.

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  • 5.
    Bier, Raven L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Vass, Mate
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Effects of ecosystem size-induced environmental fluctuations on the temporal dynamics of community assembly mechanisms2022In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 16, no 12, p. 2635-2643Article in journal (Refereed)
    Abstract [en]

    Understanding processes that determine community membership and abundance is important for many fields from theoretical community ecology to conservation. However, spatial community studies are often conducted only at a single timepoint despite the known influence of temporal variability on community assembly processes. Here we used a spatiotemporal study to determine how environmental fluctuation differences induced by mesocosm volumes (larger volumes were more stable) influence assembly processes of aquatic bacterial metacommunities along a press disturbance gradient. By combining path analysis and network approaches, we found mesocosm size categories had distinct relative influences of assembly process and environmental factors that determined spatiotemporal bacterial community composition, including dispersal and species sorting by conductivity. These processes depended on, but were not affected proportionately by, mesocosm size. Low fluctuation, large mesocosms primarily developed through the interplay of species sorting that became more important over time and transient priority effects as evidenced by more time-delayed associations. High fluctuation, small mesocosms had regular disruptions to species sorting and greater importance of ecological drift and dispersal limitation indicated by lower richness and higher taxa replacement. Together, these results emphasize that environmental fluctuations influence ecosystems over time and its impacts are modified by biotic properties intrinsic to ecosystem size.

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  • 6. Bohus, Veronika
    et al.
    Tóth, Erika M.
    Székely, Anna J.
    Makk, Judit
    Baranyi, Krisztián
    Patek, Gábor
    Schunk, János
    Márialigeti, Károly
    Microbiological investigation of an industrial ultra pure supply water plant using cultivation-based and cultivation-independent methods2010In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 44, no 20, p. 6124-6132Article in journal (Refereed)
    Abstract [en]

    Ultra pure waters (UPW), characterized by extremely low salt and nutrient concentrations, can suffer from microbial contamination which causes biofouling and biocorrosion, possibly leading to reduced lifetime and increased operational costs. Samples were taken from an ultra pure supply water producing plant of a power plant. Scanning electron microscopic examination was carried out on the biofilms formed in the system. Biofilm, ion exchange resin, and water samples were characterized by culture-based methods and molecular fingerprinting (terminal restriction fragment length polymorphism [T-RFLP] analysis and molecular cloning). Identification of bacteria was based on 16S rDNA sequence comparison. A complex microbial community structure was revealed. Nearly 46% of the clones were related to as yet uncultured bacteria. The community profiles of the water samples were the most diverse and most of bacteria were recruited from bacterial communities of tube surface and ion exchange resin biofilms. Microbiota of different layers of the mixed bed ion exchange resin showed the highest similarity. Most of the identified taxa (dominated by β-Proteobacteria) could take part in microbially influenced corrosion. © 2010 Elsevier Ltd.

  • 7.
    Boros, Emil
    et al.
    MTA Ctr Ecol Res, GINOP Sustainable Ecosyst, Danube Res Inst, Klebelsberg Kuno Str 3 POB 35, H-8237 Tihany, Hungary.
    V.-Balogh, Katalin
    MTA Ctr Ecol Res, Balaton Limnol Inst, Tihany, Hungary.
    Csitári, Bianka
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Eötvös Loránd Univ, Dept Microbiol, Budapest, Hungary.
    Vörös, Lajos
    MTA Ctr Ecol Res, Balaton Limnol Inst, Tihany, Hungary.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Macrophytes and groundwater drive extremely high organic carbon concentration of soda pans2020In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 65, no 9, p. 1555-1568Article in journal (Refereed)
    Abstract [en]
    1. Endorheic soda pans are among the highest dissolved organic carbon (DOC) content aquatic systems on the planet with concentrations up to 1 g/L. Considering the importance of inland waters in the global carbon cycle, understanding the drivers of such outstanding organic carbon pools is eminent. The soda pans of the Carpathian Basin present a wide variability of biotic and abiotic characteristics that provide an adequate system to assess the determinants of extreme high DOC concentrations. Here, we demonstrate through a multi‐site comparison, a multi‐year seasonal monitoring, and a laboratory experiment that the dissolved organic matter content of the highest DOC concentration soda pans is primarily of groundwater and emergent macrophyte origin.
    2. More precisely, the multi‐site comparison of 14 soda pans revealed that variation of coloured dissolved organic matter (CDOM) content of the surface water of soda pans is partially explained by the CDOM content (22% of variation) of local groundwater, indicating the significant role of allochthonous terrestrial DOC sources. Further 23% of CDOM variation could be accounted for by Bolboschoenus maritimus species‐specific emergent macrophyte cover, while the contribution of Phragmites australis cover was only minor.
    3. In line with the results of the multi‐site comparison, our decomposition experiment demonstrated that both B. maritimus and P. australis have the potential to release substantial amount of organic matter into soda pans. However, the organic matter release of B. maritimus leads to twice as high DOC and 3.5‐times higher CDOM concentrations than P. australis. Considering previous organic matter release studies, we concluded that P. australis is a relatively low organic matter releaser emergent macrophyte, and therefore the species composition of emergent macrophytes has to be carefully considered in autochthonous plant‐derived DOM estimations.
    4. Finally, the multi‐year seasonal monitoring of two distinctive soda pans showed that the high organic matter concentrations depend not only on their intrinsic characteristics but also on interannual variability. More precisely, we demonstrated that the highest CDOM and DOC concentrations that occurred in a coloured (i.e. brown, low total suspended solids) soda pan with extensive (95%) macrophyte cover dominated by B. maritimus were measured in a period characterised by high pH and low water levels, which were presumably the consequence of increased evaporation due to decreased precipitation and above average temperature.
    5. Our results indicate that considering climate change trends common for most endorheic regions (i.e. increased temperature and modified precipitation regimes), extremely high organic matter concentrations might become more frequent in the near future in local water bodies, particularly in those highly influenced by groundwater inflow. Furthermore, soda pans with vast specific macrophyte cover and substantial groundwater inflow might become organic carbon processing hotspots.
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  • 8.
    Csitári, Bianka
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Macrophyte cover and groundwater as the key drivers of the extremelyhigh organic carbon concentration of soda pans2019Data set
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  • 9.
    Csitári, Bianka
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary.;Karolinska Inst, Dept Microbiol Tumor & Cell Biol, Solnavagen 9, S-17165 Stockholm, Sweden..
    Bedics, Anna
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary.;Hungarian Univ Agr & Life Sci, Inst Aquaculture & Environm Safety, Dept Mol Ecol, Pater Karoly Utca 1, H-2100 Godollo, Hungary..
    Felföldi, Tamas
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary.;Ctr Ecol Res, Inst Aquat Ecol, Karolina U 29, H-1113 Budapest, Hungary..
    Boros, Emil
    Ctr Ecol Res, Inst Aquat Ecol, Karolina U 29, H-1113 Budapest, Hungary..
    Nagy, Hajnalka
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary..
    Mathe, Istvan
    Sapientia Hungarian Univ Transylvania, Dept Bioengn, Piata Libertatii 1, Miercurea Ciuc 530104, Romania..
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish Univ Agr Sci SLU, Dept Aquat Sci & Assessment, Box 7050, S-75007 Uppsala, Sweden..
    Anion-type modulates the effect of salt stress on saline lake bacteria2022In: Extremophiles, ISSN 1431-0651, E-ISSN 1433-4909, Vol. 26, article id 12Article in journal (Refereed)
    Abstract [en]

    Beside sodium chloride, inland saline aquatic systems often contain other anions than chloride such as hydrogen carbonate and sulfate. Our understanding of the biological effects of salt composition diversity is limited; therefore, the aim of this study was to examine the effect of different anions on the growth of halophilic bacteria. Accordingly, the salt composition and concentration preference of 172 strains isolated from saline and soda lakes that differed in ionic composition was tested using media containing either carbonate, chloride or sulfate as anion in concentration values ranging from 0 to 0.40 mol/L. Differences in salt-type preference among bacterial strains were observed in relationship to the salt composition of the natural habitat they were isolated from indicating specific salt-type adaptation. Sodium carbonate represented the strongest selective force, while majority of strains was well-adapted to growth even at high concentrations of sodium sulfate. Salt preference was to some extent associated with taxonomy, although variations even within the same bacterial species were also identified. Our results suggest that the extent of the effect of dissolved salts in saline lakes is not limited to their concentration but the type of anion also substantially impacts the growth and survival of individual microorganisms.

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  • 10.
    Felfoldi, Tamas
    et al.
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary..
    Nagymate, Zsuzsanna
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary..
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Jurecska, Laura
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary..
    Marialigeti, Karoly
    Eotvos Lorand Univ, Dept Microbiol, Pazmany Peter Stny 1-C, H-1117 Budapest, Hungary..
    Biological treatment of coke plant effluents: from a microbiological perspective2020In: BIOLOGIA FUTURA, ISSN 2676-8615, Vol. 71, no 4, p. 359-370Article, review/survey (Refereed)
    Abstract [en]

    During coke production, large volume of effluent is generated, which has a very complex chemical composition and contains several toxic and carcinogenic substances, mainly aromatic compounds, cyanide, thiocyanate and ammonium. The composition of these high-strength effluents is very diverse and depends on the quality of coals used and the operating and technological parameters of coke ovens. In general, after initial physicochemical treatment, biological purification steps are applied in activated sludge bioreactors. This review summarizes the current knowledge on the anaerobic and aerobic transformation processes and describes key microorganisms, such as phenol- and thiocyanate-degrading, floc-forming, nitrifying and denitrifying bacteria, which contribute to the removal of pollutants from coke plant effluents. Providing the theoretical basis for technical issues (in this case the microbiology of coke plant effluent treatment) aids the optimization of existing technologies and the design of new management techniques.

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  • 11. Felföldi, Tamás
    et al.
    Székely, Anna J
    Gorál, Róbert
    Barkács, Katalin
    Scheirich, Gergely
    András, Judit
    Rácz, Anikó
    Márialigeti, Károly
    Polyphasic bacterial community analysis of an aerobic activated sludge removing phenols and thiocyanate from coke plant effluent2010In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, no 10, p. 3406-3414Article in journal (Refereed)
    Abstract [en]

    Biological purification processes are effective tools in the treatment of hazardous wastes such as toxic compounds produced in coal coking. In this study, the microbial community of a lab-scale activated sludge system treating coking effluent was assessed by cultivation-based (strain isolation and identification, biodegradation tests) and culture-independent techniques (sequence-aided T-RFLP, taxon-specific PCR). The results of the applied polyphasic approach showed a simple microbial community dominated by easily culturable heterotrophic bacteria. Comamonas badia was identified as the key microbe of the system, since it was the predominant member of the bacterial community, and its phenol degradation capacity was also proved. Metabolism of phenol, even at elevated concentrations (up to 1500 mg/L), was also presented for many other dominant (Pseudomonas, Rhodanobacter, Oligella) and minor (Alcaligenes, Castellaniella, Microbacterium) groups, while some activated sludge bacteria (Sphingomonas, Rhodopseudomonas) did not tolerate it even in lower concentrations (250 mg/L). In some cases, closely related strains showed different tolerance and degradation properties. Members of the genus Thiobacillus were detected in the activated sludge, and were supposedly responsible for the intensive thiocyanate biodegradation observed in the system. Additionally, some identified bacteria (e.g. C. badia and the Ottowia-related strains) might also have had a significant impact on the structure of the activated sludge due to their floc-forming abilities. © 2009 Elsevier Ltd. All rights reserved.

  • 12.
    Garcia, Sarahi L
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Bergvall, Christoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Schattenhofer, Martha
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Peura, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish Univ Agr Sci, Sci Life Lab, Dept Forest Mycol & Plant Pathol, Uppsala, Sweden;Uppsala Univ, Dept Cell & Mol Biol, Uppsala, Sweden.
    Decreased Snow Cover Stimulates Under-Ice Primary Producers but Impairs Methanotrophic Capacity2019In: mSphere, E-ISSN 2379-5042, Vol. 4, no 1, article id e00626-18Article in journal (Refereed)
    Abstract [en]

    Climate change scenarios anticipate decreased spring snow cover in boreal and subarctic regions. Forest lakes are abundant in these regions and substantial contributors of methane emissions. To investigate the effect of reduced snow cover, we experimentally removed snow from an anoxic frozen lake. We observed that the removal of snow increased light penetration through the ice, increasing water temperature and modifying microbial composition in the different depths. Chlorophyll a and b concentrations increased in the upper water column, suggesting activation of algal primary producers. At the same time, Chlorobiaceae, one of the key photosynthetic bacterial families in anoxic lakes, shifted to lower depths. Moreover, a decrease in the relative abundance of methanotrophs within the bacterial family Methylococcaceae was detected, concurrent with an increase in methane concentration in the water column. These results indicate that decreased snow cover impacts both primary production and methane production and/or consumption, which may ultimately lead to increased methane emissions after spring ice off. IMPORTANCE Small lakes are an important source of greenhouse gases in the boreal zone. These lakes are severely impacted by the winter season, when ice and snow cover obstruct gas exchange between the lake and the atmosphere and diminish light availability in the water column. Currently, climate change is resulting in reduced spring snow cover. A short-term removal of the snow from the ice stimulated algal primary producers and subsequently heterotrophic bacteria. Concurrently, the relative abundance of methanotrophic bacteria decreased and methane concentrations increased. Our results increase the general knowledge of microbial life under ice and, specifically, the understanding of the potential impact of climate change on boreal lakes.

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  • 13.
    Langenheder, Silke
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Berga, Mercé
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Östman, Örjan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Temporal variation of beta-diversity and assembly mechanisms in a bacterial metacommunity2012In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 6, no 6, p. 1107-1114Article in journal (Refereed)
    Abstract [en]

    The turnover of community composition across space, beta-diversity, is influenced by different assembly mechanisms, which place varying weight on local habitat factors, such as environmental conditions and species interactions, and regional factors such as dispersal and history. Several assembly mechanisms may function simultaneously; however, little is known about how their importance changes over time and why. Here, we implemented a field survey where we sampled a bacterial metacommunity consisting of 17 rock pools located at the Swedish Baltic Sea coast at 11 occasions during 1 year. We determined to which extent communities were structured by different assembly mechanisms using variation partitioning and studied changes in beta-diversity across environmental gradients over time. beta-Diversity was highest at times of high overall productivity and environmental heterogeneity in the metacommunity, at least partly due to species sorting, that is, selection of taxa by the prevailing environmental conditions. In contrast, dispersal-driven assembly mechanisms were primarily detected at times when beta-diversity was relatively low. There were no indications for strong and persistent differences in community composition or beta-diversity between permanent and temporary pools, indicating that the physical disturbance regime is of relatively minor importance. In summary, our study clearly suggests that there are temporal differences in the relative importance of different assembly mechanisms related to abiotic factors and shows that the temporal variability of those factors is important for a more complete understanding of bacterial metacommunity dynamics.

  • 14.
    Langenheder, Silke
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Species sorting and neutral processes are both important during the initial assembly of bacterial communities2011In: The ISME Journal, ISSN 1751-7362, Vol. 5, no 7, p. 1086-1094Article in journal (Refereed)
    Abstract [en]

    Many studies have shown that species sorting, that is, the selection by local environmental conditions is important for the composition and assembly of bacterial communities. On the other hand, there are other studies that could show that bacterial communities are neutrally assembled. In this study, we implemented a microcosm experiment with the aim to determine, at the same time, the importance of species sorting and neutral processes for bacterial community assembly during the colonisation of new, that is, sterile, habitats, by atmospheric bacteria. For this we used outdoor microcosms, which contained sterile medium from three different rock pools representing different environmental conditions, which were seeded by rainwater bacteria. We found some evidence for neutral assembly processes, as almost every 4th taxon growing in the microcosms was also detectable in the rainwater sample irrespective of the medium. Most of these taxa belonged to widespread families with opportunistic growth strategies, such as the Pseudomonadaceae and Comamonadaceae, indicating that neutrally assembled taxa may primarily be generalists. On the other hand, we also found evidence for species sorting, as one out of three media selected a differently composed bacterial community. Species sorting effects were relatively weak and established themselves via differences in relative abundance of generalists among the different media, as well as media-specific occurrences of a few specific taxa. In summary, our results suggest that neutral and species sorting processes interact during the assembly of bacterial communities and that their importance may differ depending on how many generalists and specialists are present in a community.

  • 15.
    Lundy, Lian
    et al.
    Luleå Univ Technol, DRIZZLE Ctr Excellence, VA Tekn, S-97187 Luleå, Sweden.
    Fatta-Kassinos, Despo
    Univ Cyprus, Dept Civil & Environm Engn, Sch Engn, POB 20537, CY-1678 Nicosia, Cyprus; Univ Cyprus, Nireas Int Water Res Ctr, Sch Engn, POB 20537, CY-1678 Nicosia, Cyprus.
    Slobodnik, Jaroslav
    Environm Inst, Okruzna 784-42, Kos 97241, Slovakia.
    Karaolia, Popi
    Univ Cyprus, Dept Civil & Environm Engn, Sch Engn, POB 20537, CY-1678 Nicosia, Cyprus; Univ Cyprus, Nireas Int Water Res Ctr, Sch Engn, POB 20537, CY-1678 Nicosia, Cyprus.
    Cirka, Lubos
    Environm Inst, Okruzna 784-42, Kos 97241, Slovakia; Slovak Univ Technol Bratislava, Fac Chem & Food Technol, Radlinskeho 9, Bratislava 81237, Slovakia.
    Kreuzinger, Norbert
    Tech Univ Wien, Inst Water Qual & Resources Management, Karlspl 13-226-1, A-1040 Vienna, Austria.
    Castiglioni, Sara
    Ist Ric Farmacol Mario Negri IRCCS, Dept Environm Sci, Via Mario Negri 2, I-20156 Milan, Italy.
    Bijlsma, Lubertus
    Univ Jaume 1, Res Inst Pesticides & Water, Environm & Publ Hlth Analyt Chem, Castellon de La Plana, Spain.
    Dulio, Valeria
    Natl Inst Environm & Ind Risks, Rue Jacques Taffanel,Parc Technol ALATA, F-60550 Verneuil En Halatte, France.
    Deviller, Genevieve
    DERAC Consulting, 104 Grande Rue, F-44240 Nantes, France.
    Lai, Foon Yin
    Swedish Univ Agr Sci SLU, Dept Aquat Sci & Assessment, SE-75007 Uppsala, Sweden.
    Alygizakis, Nikiforos
    Environm Inst, Okruzna 784-42, Kos 97241, Slovakia; Natl & Kapodistrian Univ Athens, Lab Analyt Chem, Dept Chem, Athens, Greece.
    Barneo, Manuela
    Univ Jaume 1, Unidad Predept Med, Fac Salud, Castellon de La Plana 12071, Spain.
    Baz-Lomba, Jose Antonio
    Norwegian Inst Water Res NIVA, Gaustadalleen 21, NO-0349 Oslo, Norway.
    Béen, Frederic
    KWR Water Res Inst, Groningenhaven 7, NL-3430 BB Nieuwegein, Netherlands.
    Cíchová, Marianna
    Water Res Inst, Nabrezie Arm Gen L Svobodu 5, Bratislava 81249, Slovakia.
    Conde-Pérez, Kelly
    Univ A Coruna, Microbiol Serv, Univ Hosp, Biomed Res Inst, La Coruna, Spain.
    Covaci, Adrian
    Univ Antwerp, Toxicol Ctr, Univ Pl 1, B-2610 Antwerp, Belgium.
    Donner, Erica
    Univ South Australia, Future Ind Inst FII, Bldg X,Univ Blvd, Mawson Lakes, SA 5095, Australia.
    Ficek, Andrej
    Comenius Univ, Fac Nat Sci, Dept Mol Biol, Bratislava, Slovakia.
    Hassard, Francis
    Cranfield Univ, Sch Water Energy & Environm, Cranfield MK43 0AL, Beds, England.
    Hedström, Annelie
    Luleå Univ Technol, DRIZZLE Ctr Excellence, VA Tekn, S-97187 Luleå, Sweden.
    Hernandez, Félix
    Univ Jaume 1, Res Inst Pesticides & Water, Environm & Publ Hlth Analyt Chem, Castellon de La Plana, Spain.
    Janská, Veronika
    Water Res Inst, Nabrezie Arm Gen L Svobodu 5, Bratislava 81249, Slovakia.
    Jellison, Kristen
    Lehigh Univ, Dept Civil & Environm Engn, 1 West Packer Ave, Bethlehem, PA 18015 USA.
    Hofman, Jan
    Univ Bath, Water Innovat & Res Ctr, Dept Chem Engn, Bath BA2 7AY, Avon, England.
    Hill, Kelly
    Water Res Australia Ltd, Level 2,250 Victoria Sq, Adelaide, SA 5000, Australia.;Water Res Australia Ltd, GPO Box 1751, Adelaide, SA 5001, Australia.
    Hong, Pei-Ying
    King Abdullah Univ Sci & Technol KAUST, Water Desalinat & Reuse Ctr, Div Biol & Environm Sci & Engn, Thuwal 239556900, Saudi Arabia.
    Kasprzyk-Hordern, Barbara
    Univ Bath, Dept Chem, Bath, Avon, England.
    Kolarevic, Stoimir
    Univ Belgrade, Inst Biol Res Sinisa Stankovic, Natl Inst Republ Serbia, Dept Hydroecol & Water Protect, Bulevar Despota Stefana 142, Belgrade 11000, Serbia.
    Krahulec, Jan
    Comenius Univ, Fac Nat Sci, Dept Mol Biol, Bratislava, Slovakia.
    Lambropoulou, Dimitra
    Aristotle Univ Thessaloniki, Lab Environm Pollut Control, Dept Chem, GR-54124 Thessaloniki, Greece; Balkan Ctr, Ctr Interdisciplinary Res & Innovat CIRI AUTH, GR-57001 Thessaloniki, Greece.
    de Llanos, Rosa
    Univ Jaume 1, Unidad Predept Med, Fac Salud, Castellon de La Plana 12071, Spain.
    Mackul'ak, Tomás
    Slovak Univ Technol Bratislava, Fac Chem & Food Technol, Inst Chem & Environm Engn, Radlinskeho 9, Bratislava 81237, Slovakia.
    Martinez-García, Lorena
    Univ Alcala De Henares, IMDEA Water Inst, Sci & Technol Campus,Ave Punto Com 2, Alcala De Henares 28805, Spain.
    Martínez, Francisco
    Univ Alcala De Henares, IMDEA Water Inst, Sci & Technol Campus,Ave Punto Com 2, Alcala De Henares 28805, Spain.
    Medema, Gertjan
    KWR Water Res Inst, Groningenhaven 7, NL-3430 BB Nieuwegein, Netherlands.
    Micsinai, Adrienn
    WESSLING Hungary Kft Budapest, Anonymus U 6, H-1045 Budapest, Hungary.
    Myrmel, Mette
    Norwegian Univ Life Sci, Fac Vet Med, Virol Unit, POB 8146 Dept, N-0033 Oslo, Norway.
    Nasser, Mohammed
    Univ A Coruna, Microbiol Serv, Univ Hosp, Biomed Res Inst, La Coruna, Spain.
    Niederstätter, Harald
    Med Univ Innsbruck, Inst Legal Med & Core Facil Metabol, Muellerstr 44, A-6020 Innsbruck, Austria.
    Nozal, Leonor
    Norwegian Univ Life Sci, Fac Vet Med, Virol Unit, POB 8146 Dept, N-0033 Oslo, Norway.
    Oberacher, Herbert
    Med Univ Innsbruck, Inst Legal Med & Core Facil Metabol, Muellerstr 44, A-6020 Innsbruck, Austria.
    Ocenásková, Vera
    TG Masaryk Water Res Inst, Branch Anal & Assessment Environm Components, Pri, Podbabska 2582-30, Prague 16000 6, Czech Republic.
    Ogorzaly, Leslie
    Luxembourg Inst Sci & Technol LIST, Environm Res & Innovat Dept, 41 Rue Brill, L-4422 Belvaux, Luxembourg.
    Papadopoulos, Dimitrios
    Aristotle Univ Thessaloniki, Lab Environm Pollut Control, Dept Chem, GR-54124 Thessaloniki, Greece.
    Peinado, Beatriz
    Univ Alcala De Henares, IMDEA Water Inst, Sci & Technol Campus,Ave Punto Com 2, Alcala De Henares 28805, Spain.
    Pitkänen, Tarja
    Finnish Inst Hlth & Welf, Expert Microbiol Unit, Neulaniementie 4, FI-70701 Kuopio, Finland; Univ Helsinki, Fac Vet Med, Dept Food Hyg & Environm Hlth, Agnes Sjobergin Katu 2, FI-00014 Helsinki, Finland.
    Poza, Margarita
    Univ A Coruna, Microbiol Serv, Univ Hosp, Biomed Res Inst, La Coruna, Spain.
    Rumbo-Feal, Soraya
    Univ A Coruna, Microbiol Serv, Univ Hosp, Biomed Res Inst, La Coruna, Spain.
    Blanca Sánchez, Maria
    Univ Alcala De Henares, IMDEA Water Inst, Sci & Technol Campus,Ave Punto Com 2, Alcala De Henares 28805, Spain.
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Soltysova, Andrea
    Comenius Univ, Fac Nat Sci, Dept Mol Biol, Bratislava, Slovakia; Slovak Acad Sci, Biomed Res Ctr, Inst Clin & Translat Res, Dubravska Cesta 9, Bratislava 84505, Slovakia.
    Thomaidis, Nikolaos S.
    Natl & Kapodistrian Univ Athens, Lab Analyt Chem, Dept Chem, Athens, Greece.
    Vallejo, Juan
    Univ A Coruna, Microbiol Serv, Univ Hosp, Biomed Res Inst, La Coruna, Spain.
    van Nuijs, Alexander
    Univ Antwerp, Toxicol Ctr, Univ Pl 1, B-2610 Antwerp, Belgium.
    Ware, Vassie
    Lehigh Univ, Dept Civil & Environm Engn, 1 West Packer Ave, Bethlehem, PA 18015 USA.
    Viklander, Maria
    Luleå Univ Technol, DRIZZLE Ctr Excellence, VA Tekn, S-97187 Luleå, Sweden.
    Making Waves: Collaboration in the time of SARS-CoV-2-rapid development of an international co-operation and wastewater surveillance database to support public health decision-making2021In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 199, article id 117167Article in journal (Refereed)
    Abstract [en]

    The presence of SARS-CoV-2 RNA in wastewater was first reported in March 2020. Over the subsequent months, the potential for wastewater surveillance to contribute to COVID-19 mitigation programmes has been the focus of intense national and international research activities, gaining the attention of policy makers and the public. As a new application of an established methodology, focused collaboration between public health practitioners and wastewater researchers is essential to developing a common understanding on how, when and where the outputs of this non-invasive community-level approach can deliver actionable outcomes for public health authorities. Within this context, the NORMAN SCORE "SARS-CoV-2 in sewage" database provides a platform for rapid, open access data sharing, validated by the uploading of 276 data sets from nine countries to-date. Through offering direct access to underpinning meta-data sets (and describing its use in data interpretation), the NORMAN SCORE database is a resource for the development of recommendations on minimum data requirements for wastewater pathogen surveillance. It is also a tool to engage public health practitioners in discussions on use of the approach, providing an opportunity to build mutual understanding of the demand and supply for data and facilitate the translation of this promising research application into public health practice.

  • 16. Malki, Kema
    et al.
    Rosario, Karyna
    Sawaya, Natalie A.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Tisza, Michael J.
    Breitbart, Mya
    Prokaryotic and Viral Community Composition of Freshwater Springs in Florida, USA2020In: mBio, ISSN 2161-2129, E-ISSN 2150-7511, Vol. 11, no 2, article id e00436-20Article in journal (Refereed)
    Abstract [en]

    Aquifers, which are essential underground freshwater reservoirs worldwide, are understudied ecosystems that harbor diverse forms of microbial life. This study investigated the abundance and composition of prokaryotic and viral communities in the outflow of five springs across northern Florida, USA, as a proxy of microbial communities found in one of the most productive aquifers in the world, the Floridan aquifer. The average abundances of virus-like particles and prokaryotic cells were slightly lower than those reported from other groundwater systems, ranging from 9.6 × 10 3 ml −1 to 1.1 × 10 5 ml −1 and 2.2 × 10 3 ml −1 to 3.4 × 10 4 ml −1 , respectively. Despite all of the springs being fed by the Floridan aquifer, sequencing of 16S rRNA genes and viral metagenomes (viromes) revealed unique communities in each spring, suggesting that groundwater microbial communities are influenced by land usage in recharge zones. The prokaryotic communities were dominated by Bacteria , and though the most abundant phyla ( Proteobacteria , Cyanobacteria , and Bacteroidetes ) were found in relatively high abundance across springs, variation was seen at finer taxonomic resolution. The viral sequences were most similar to those described from other aquatic environments. Sequencing resulted in the completion of 58 novel viral genomes representing members of the order Caudovirales as well as prokaryotic and eukaryotic single-stranded DNA (ssDNA) viruses. Sequences similar to those of ssDNA viruses were detected at all spring sites and dominated the identifiable sequences at one spring site, showing that these small viruses merit further investigation in groundwater systems.

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  • 17.
    Malki, Kema
    et al.
    Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA..
    Sawaya, Natalie A.
    Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA..
    Tisza, Michael J.
    NCI, Lab Cellular Oncol, NIH, Bethesda, MD 20892 USA..
    Coutinho, Felipe H.
    Univ Miguel Hernandez, Dept Prod Vegetal & Microbiol, Alacant, Spain..
    Rosario, Karyna
    Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA..
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Breitbart, Mya
    Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA..
    Spatial and Temporal Dynamics of Prokaryotic and Viral Community Assemblages in a Lotic System (Manatee Springs, Florida)2021In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 87, no 18, article id e00646-21Article in journal (Refereed)
    Abstract [en]

    How from high-magnitude springs fed by the Floridan aquifer system contributes hundreds of liters of water per second to rivers, creating unique lotic systems. Despite their importance as freshwater sources and their contributions to the state's major rivers, little is known about the composition and spatiotemporal variability of prokaryotic and viral communities of these spring systems or their influence on downstream river sites. At four time points throughout a year, we determined the abundance and diversity of prokaryotic and viral communities at three sites within the first-magnitude Manatee Springs system (the spring head where water emerges from the aquifer, a mixed region where the spring run ends, and a downstream site in the Suwannee River). The abundance of prokaryotes and virus-like particles increased 100-fold from the spring head to the river and few members from the head communities persisted in the river at low abundance, suggesting the springs play a minor role in seeding downstream communities. Prokaryotic and viral communities within Manatee Springs clustered by site, with seasonal variability likely driven by flow. As water flowed through the system, microbial community composition was affected by changes in physiochemical parameters and community coalescence. Evidence of species sorting and mass effects could be seen in the assemblages. Greater temporal fluctuations were observed in prokaryotic and viral community composition with increasing distance from the spring outflow, reflecting the relative stability of the groundwater environment, and comparisons to springs from prior work reaffirmed that distinct first-magnitude springs support unique communities. IMPORTANCE Prokaryotic and viral communities are central to food webs and biogeochemical processes in aquatic environments, where they help maintain ecosystem health. The Floridan aquifer system (FAS), which is the primary drinking water source for millions of people in the southeastern United States, contributes large amounts of freshwater to major river systems in Florida through its springs. However, there is a paucity of information regarding the spatiotemporal dynamics of microbial communities in these essential flowing freshwater systems. This work explored the prokaryotic and viral communities in a first-magnitude spring system fed by the FAS that discharges millions of liters of water per day into the Suwannee River. This study examined microbial community composition through space and time as well as the environmental parameters and metacommunity assembly mechanisms that shape these communities, providing a foundational understanding for monitoring future changes.

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  • 18.
    Marton, Zsuzsanna
    et al.
    Ctr Ecol Res, Inst Aquat Ecol, H-1113 Budapest, Hungary.;Ctr Ecol Res, Natl Multidisciplinary Lab Climate Change, H-1113 Budapest, Hungary.;Eotvos Lorand Univ, Doctoral Sch Environm Sci, H-1117 Budapest, Hungary..
    Csitári, Bianka
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Eotvos Lorand Univ, Doctoral Sch Environm Sci, H-1117 Budapest, Hungary.;Karolinska Inst, S-17165 Stockholm, Sweden..
    Felfoldi, Tamas
    Ctr Ecol Res, Inst Aquat Ecol, H-1113 Budapest, Hungary.;Eotvos Lorand Univ, Dept Microbiol, H-1117 Budapest, Hungary..
    Hidas, Andras
    Ctr Ecol Res, Inst Aquat Ecol, H-1113 Budapest, Hungary.;Eotvos Lorand Univ, Doctoral Sch Environm Sci, H-1117 Budapest, Hungary..
    Jordan, Ferenc
    Univ Parma, Dept Chem Life Sci & Environm Sustainabil, I-43124 Parma, Italy..
    Szabo, Attila
    Ctr Ecol Res, Inst Aquat Ecol, H-1113 Budapest, Hungary.;Swedish Univ Agr Sci, S-75007 Uppsala, Sweden..
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish Univ Agr Sci, S-75007 Uppsala, Sweden..
    Contrasting response of microeukaryotic and bacterial communities to the interplay of seasonality and local stressors in shallow soda lakes2023In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 99, no 9, article id fiad095Article in journal (Refereed)
    Abstract [en]

    Seasonal environmental variation is a leading driver of microbial planktonic community assembly and interactions. However, departures from usual seasonal trends are often reported. To understand the role of local stressors in modifying seasonal succession, we sampled fortnightly, throughout three seasons, five nearby shallow soda lakes exposed to identical seasonal and meteorological changes. We characterised their microeukaryotic and bacterial communities by amplicon sequencing of the 16S and 18S rRNA gene, respectively. Biological interactions were inferred by analyses of synchronous and time-shifted interaction networks, and the keystone taxa of the communities were topologically identified. The lakes showed similar succession patterns during the study period with spring being characterised by the relevance of trophic interactions and a certain level of community stability followed by a more dynamic and variable summer-autumn period. Adaptation to general seasonal changes happened through shared core microbiome of the lakes. Stochastic events such as desiccation disrupted common network attributes and introduced shifts from the prevalent seasonal trajectory. Our results demonstrated that, despite being extreme and highly variable habitats, shallow soda lakes exhibit certain similarities in the seasonality of their planktonic communities, yet local stressors such as droughts instigate deviations from prevalent trends to a greater extent for microeukaryotic than for bacterial communities.

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  • 19. Máthé, I.
    et al.
    Táncsics, A.
    György, Éva
    Pohner, Zsuzsanna
    Vladár, P.
    Székely, Anna J.
    Márialigeti, K.
    Investigation of mineral water springs of Miercurea Ciuc (Csíkszereda) region (Romania) with cultivation-dependent microbiological methods2010In: Acta Microbiologica et Immunologica Hungarica, ISSN ISSN 1217-8950, EISSN 1588-2640 (Online), Vol. 57, no 2, p. 109-122Article in journal (Refereed)
    Abstract [en]

    Water samples of ten mineral water springs at Miercurea Ciuc (Csíkszereda) region (Romania) were examined during 2005-2006 using cultivation-dependent microbiological methods. The results of standard hygienic bacteriological tests showed that the Hargita Spring had perfect and five other springs had microbiologically acceptable water quality (Zsögöd-, Nagy-borvíz-, Taploca-, Szentegyháza- and Lobogó springs). The water of Borsáros Spring was exceptionable (high germ count, presence of Enterococcus spp.).Both standard bacteriological and molecular microbiological methods indicated that the microbiological water quality of the Szeltersz-, Nádasszék- and Délo springs was not acceptable. Bad water quality resulted from inadequate spring catchment and hygiene (low yield, lack of runoff, negligent usage of the springs, horse manure around the spring).The 16S rRNA gene-based identification of strains isolated on standard meat-peptone medium resulted in the detection of typical aquatic organisms such as Shewanella baltica, Aeromonas spp., Pseudomonas veronii, Psychrobacter sp,. Acinetobacter spp. and allochthonous microbes, like Nocardia, Streptomyces, Bacillus, Microbacterium , and Arthrobacter strains indicating the impact of soil. Other allochthonous microbes, such as Staphylococcus spp., Micrococcus sp., Lactococcus sp., Clostridium butyricum, Yersinia spp., Aerococcus sp., may have originated from animal/human sources. © 2010 Akadémiai Kiadó, Budapest.

  • 20.
    Nikolausz, Marcell
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Kappelmeyer, Uwe
    Székely, Anna
    Rusznyák, Anna
    Márialigeti, Károly
    Kästner, Matthias
    Diurnal redox fluctuation and microbial activity in the rhizosphere of wetland plants2008In: European journal of soil biology, ISSN 1164-5563, E-ISSN 1778-3615, Vol. 44, no 3, p. 324-333Article in journal (Refereed)
    Abstract [en]

    Wetland plants release oxygen through the aerenchyma system to the roots, providing oxic habitats in the rhizosphere. The consumption of the oxygen during the night establishes a diurnal fluctuation of the redox conditions (-320 mV to +300 mV) that explains the coexistence of aerobic and anaerobic microorganisms in the rhizosphere. The redox fluctuation and its effect on the activity of rhizosphere microorganisms were investigated by RNA-based fingerprinting techniques in a laboratory scale reactor planted with Juncus effusus. The denaturing gradient gel electrophoresis (DGGE) patterns of 16S rRNA obtained with "universal" primers were very similar regardless of the time of sampling, indicating that the overall ribosome level of the predominantly active members did not change significantly. The amoA transcript DGGE patterns showed moderate diurnal dynamics with specific bands observed either in day or night samples. However, the majority of amoA genes were continuously expressed, indicating that the activity of functional genes may only partly be a measure sensitive enough for tracing the physiological activity on a short time scale. The results indicate that loose regulation of functional genes can be the main strategy for accommodation to fluctuating environmental conditions. The spatial separation of microbial activities as a result of diurnal fluctuating oxygen availability probably contributes to niche differentiation in the rhizosphere but this is difficult to track it at transcriptome level. © 2008 Elsevier Masson SAS. All rights reserved.

  • 21. Nikolausz, Marcell
    et al.
    Sipos, Rita
    Révész, Sára
    Szekely, Anna
    Department of Microbiology, Eötvös Loránd University of Science, Budapest, Hungary.
    Márialigeti, Károly
    Observation of bias associated with re-amplification of DNA isolated from denaturing gradient gels2005In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 244, p. 385-390Article in journal (Refereed)
    Abstract [en]

    DNA from environmental PCR products separated by denaturing gradient gel electrophoresis (DGGE) was isolated from the background smear rather than from discrete bands of the DGGE gel. The ‘‘interband’’ region was considered as a potential source of less dominant members of natural microbial communities. Surprisingly, instead of detecting new bands from the re-amplified PCR products, patterns very similar to the original ones were obtained regardless of the position of the ‘‘interband’’ region. The results suggest that the separation of amplicons by DGGE may not be perfect and band re-amplification based sequence analyses need careful interpretation.

  • 22.
    Scharnweber, Kristin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. University of Potsdam.
    Peura, Sari
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab. Swedish University of Agricultural Sciences, Uppsala.
    Attermeyer, Katrin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. WasserCluster Lunz.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish University of Agricultural Sciences, Uppsala.
    Bolender, Lucas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Buck, Moritz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab. Swedish University of Agricultural Sciences, Uppsala.
    Einarsdóttir, Karólina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Garcia, Sarahi L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab. Stockholm University.
    Gollnisch, Raphael
    Grasset, Charlotte
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Groeneveld, Marloes
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Hawkes, Jeffrey A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Lindström, Eva S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Manthey, Christin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Freie Universität Berlin.
    Övergaard, Robyn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Rengefors, Karin
    Sedano-Núñez, Vicente T.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Evolution.
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish University of Agricultural Sciences, Uppsala.
    Comprehensive analysis of chemical and biological problems associated with browning agents used in aquatic studies2021In: Limnology and Oceanography: Methods, E-ISSN 1541-5856, Vol. 19, no 12, p. 818-835Article in journal (Refereed)
    Abstract [en]

    Inland waters receive and process large amounts of colored organic matter from the terrestrial surroundings. These inputs dramatically affect the chemical, physical, and biological properties of water bodies, as well as their roles as global carbon sinks and sources. However, manipulative studies, especially at ecosystem scale, require large amounts of dissolved organic matter with optical and chemical properties resembling indigenous organic matter. Here, we compared the impacts of two leonardite products (HuminFeed and SuperHume) and a freshly derived reverse osmosis concentrate of organic matter in a set of comprehensive mesocosm- and laboratory-scale experiments and analyses. The chemical properties of the reverse osmosis concentrate and the leonardite products were very different, with leonardite products being low and the reverse osmosis concentrate being high in carboxylic functional groups. Light had a strong impact on the properties of leonardite products, including loss of color and increased particle formation. HuminFeed presented a substantial impact on microbial communities under light conditions, where bacterial production was stimulated and community composition modified, while in dark potential inhibition of bacterial processes was detected. While none of the browning agents inhibited the growth of the tested phytoplankton Gonyostomum semen, HuminFeed had detrimental effects on zooplankton abundance and Daphnia reproduction. We conclude that the effects of browning agents extracted from leonardite, particularly HuminFeed, are in sharp contrast to those originating from terrestrially derived dissolved organic matter. Hence, they should be used with great caution in experimental studies on the consequences of terrestrial carbon for aquatic systems.

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  • 23.
    Segura, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish Univ Agr Sci SLU, Dept Forest Ecol & Management, SE-90183 Umea, Sweden.
    Nilsson, Mats B.
    Swedish Univ Agr Sci SLU, Dept Forest Ecol & Management, SE-90183 Umea, Sweden.
    Schleucher, Jürgen
    Umea Univ, Dept Med Biochem & Biophys, SE-90187 Umea, Sweden.
    Haei, Mahsa
    Swedish Univ Agr Sci SLU, Dept Forest Ecol & Management, SE-90183 Umea, Sweden.
    Sparrman, Tobias
    Umea Univ, Dept Chem, SE-90187 Umea, Sweden.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Öquist, Mats G.
    Swedish Univ Agr Sci SLU, Dept Forest Ecol & Management, SE-90183 Umea, Sweden.
    Microbial utilization of simple carbon substrates in boreal peat soils at low temperatures2019In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 135, p. 438-448Article in journal (Refereed)
    Abstract [en]

    Boreal peatlands are key high-latitude ecosystem types and act as a carbon (C) sink storing an estimated 25% of the world's soil C. These environments are currently seeing the most substantial changing climate, especially during the winter. CO2 emissions during the winter can correspond to 80% of the growing season's net CO2 assimilation. Yet, our conceptual understanding of the controls on microbial metabolic activity in peat soils at temperatures <= 0 degrees C is poor. We used stable isotope probing of peat samples and tracked the fate of C-13-glucose using C-13-NMR. We show that microorganisms in frozen boreal peat soils utilize monomeric C-substrates to sustain both catabolic and anabolic metabolism at temperatures down to -5 degrees C. The C-13-substrate was transformed into C-13-CO2, different metabolites, and incorporated into membrane phospholipid fatty acids. The 16S rRNA-based community analyses revealed the activity at -3 degrees C changes the composition of the bacterial cornmunity over relevant timescales. Below 0 degrees C, small temperature changes have strong effects on process rates and small differences in winter soil temperature may affect C dynamics of northern peatlands. Understanding biological processes at low and below zero temperatures are central for the overall functioning of these systems representing one of the world's major soil C pools.

  • 24. Sipos, Rita
    et al.
    Székely, Anna J.
    Palatinszky, Márton
    Révész, Sára
    Márialigeti, Károly
    Nikolausz, Marcell
    Effect of primer mismatch, annealing temperature and PCR cycle number on 16S rRNA gene-targetting bacterial community analysis2007In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 60, no 2, p. 341-350Article in journal (Refereed)
    Abstract [en]

    In the attempt to explore complex bacterial communities of environmental samples, primers hybridizing to phylogenetically highly conserved regions of 16S rRNA genes are widely used, but differential amplification is a recognized problem. The biases associated with preferential amplification of multitemplate PCR were investigated using ’universal’ bacteria-specific primers, focusing on the effect of primer mismatch, annealing temperature and PCR cycle number. The distortion of the template-to-product ratio was measured using predefined template mixtures and environmental samples by terminal restriction fragment length polymorphism analysis. When a 1 : 1 genomic DNA template mixture of two strains was used, primer mismatches inherent in the 63F primer presented a serious bias, showing preferential amplification of the template containing the perfectly matching sequence. The extent of the preferential amplification showed an almost exponential relation with increasing annealing temperature from 47 to 61°C. No negative effect of the various annealing temperatures was observed with the 27F primer, with no mismatches with the target sequences. The number of PCR cycles had little influence on the template-to-product ratios. As a result of additional tests on environmental samples, the use of a low annealing temperature is recommended in order to significantly reduce preferential amplification while maintaining the specificity of PCR. © 2007 Federation of European Microbiological Societies.

  • 25.
    Székely, Anna J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Berga, Mercé
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Mechanisms determining the fate of dispersed bacterial communities in new environments2013In: ISME Journal, ISSN 1751-7362, Vol. 7, no 1, p. 61-71Article in journal (Refereed)
    Abstract [en]

    Recent work has shown that dispersal has an important role in shaping microbial communities. However, little is known about how dispersed bacteria cope with new environmental conditions and how they compete with local resident communities. To test this, we implemented two full-factorial transplant experiments with bacterial communities originating from two sources (freshwater or saline water), which were incubated, separately or in mixes, under both environmental conditions. Thus, we were able to separately test for the effects of the new environment with and without interactions with local communities. We determined community composition using 454-pyrosequencing of bacterial 16S rRNA to specifically target the active fraction of the communities, and measured several functional parameters. In absence of a local resident community, the net functional response was mainly affected by the environmental conditions, suggesting successful functional adaptation to the new environmental conditions. Community composition was influenced both by the source and the incubation environment, suggesting simultaneous effects of species sorting and functional plasticity. In presence of a local resident community, functional parameters were higher compared with those expected from proportional mixes of the unmixed communities in three out of four cases. This was accompanied by an increase in the relative abundance of generalists, suggesting that competitive interactions among local and immigrant taxa could explain the observed functional overachievement. In summary, our results suggest that environmental filtering, functional plasticity and competition are all important mechanisms influencing the fate of dispersed communities.

  • 26.
    Székely, Anna J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA..
    Breitbart, Mya
    Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA..
    Single-stranded DNA phages: from early molecular biology tools to recent revolutions in environmental microbiology2016In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 363, no 6, article id fnw027Article, review/survey (Refereed)
    Abstract [en]

    Single-stranded DNA (ssDNA) phages are profoundly different from tailed phages in many aspects including the nature and size of their genome, virion size and morphology, mutation rate, involvement in horizontal gene transfer, infection dynamics and cell lysis mechanisms. Despite the importance of ssDNA phages as molecular biology tools and model systems, the environmental distribution and ecological roles of these phages have been largely unexplored. Viral metagenomics and other culture-independent viral diversity studies have recently challenged the perspective of tailed, double-stranded DNA (dsDNA) phages, dominance by demonstrating the prevalence of ssDNA phages in diverse habitats. However, the differences between ssDNA and dsDNA phages also substantially limit the efficacy of simultaneously assessing the abundance and diversity of these two phage groups. Here we provide an overview of the major differences between ssDNA and tailed dsDNA phages that may influence their effects on bacterial communities. Furthermore, through the analysis of 181 published metaviromes we demonstrate the environmental distribution of ssDNA phages and present an analysis of the methodological biases that distort their study through metagenomics.

  • 27.
    Székely, Anna J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Dispersal timing and drought history influence the response of bacterioplankton to drying–rewetting stress2017In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 11, no 8, p. 1764-1776Article in journal (Refereed)
    Abstract [en]

    The extent and frequency of drought episodes is expected to increase in the following decades making it a crucial stress factor for smaller water bodies. However, very little is known about how bacterioplankton is affected by increased evaporation and how these communities reassemble after rewetting. Here, we present results from a microcosm experiment that assessed the effect of drying–rewetting stress on bacterioplankton in the light of the stress history and the rate and timing of dispersal after the rewetting. We found that the drying phase resulted mainly in a change of function, whereas the complete desiccation and rewetting processes strongly affected both composition and function, which were, however, influenced by the initial conditions and stress history of the communities. Effects of dispersal were generally stronger when it occurred at an early stage after the rewetting. At this stage, selective establishment of dispersed bacteria coupled with enhanced compositional and functional recovery was found, whereas effects of dispersal were neutral, that is, predictable by dispersal rates, at later stages. Our studies therefore show that both the stress history and the timing of dispersal are important factors that influence the response of bacterial communities to environmental change and stress events.

  • 28.
    Székely, Anna J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    The importance of species sorting in bacterial communities differs between habitat generalists and specialists2014In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 87, no 1, p. 102-112Article in journal (Refereed)
    Abstract [en]

    Recent studies have shown that the spatial turnover of bacterial communities, that is, beta-diversity, is determined by a combination of different assembly mechanisms, such as species sorting, that is, environmental filtering, and dispersal-related mechanisms. However, it is currently unclear to what extent the importance of the different mechanisms depends on community traits. Here, we implemented a study using a rock pool metacommunity to test whether habitat specialization of bacterial taxa and groups or their phylogenetic identity influenced by which mechanisms communities were assembled. Ingeneral, our results show that species sorting was the most important assembly mechanism. However, we found that a larger fraction of the variation in bacterial community composition between pools could be explained by environmental factors in case of habitat generalists, that is, taxa that were widespread and abundant in the metacommunity, compared with habitat specialists, that is, taxa that had a more restricted distribution range and tended to be rare. Differences in assembly mechanisms were observedbetween different major phyla and classes. However, also here, a larger fraction of the variation incommunity composition among pools could be explained for taxonomic groups that contained on average more habitat generalists. In summary, our results show that species sorting is stronger for themost common taxa, indicating that beta-diversity along environmental gradients can be adequately described without considering rare taxa.

  • 29. Székely, Anna J.
    et al.
    Sipos, Rita
    Berta, Birgitta
    Vajna, Balázs
    Hajdú, Csaba
    Márialigeti, Károly
    DGGE and T-RFLP analysis of bacterial succession during mushroom compost production and sequence-aided T-RFLP profile of mature compost2009In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 57, no 3, p. 522-533Article in journal (Refereed)
    Abstract [en]

    The amount of button mushroom (Agaricus bisporus) harvested from compost is largely affected by the microbial processes taking place during composting and the microbes inhabiting the mature compost. In this study, the microbial changes during the stages of this specific composting process were monitored, and the dominant bacteria of the mature compost were identified to reveal the microbiological background of the favorable properties of the heat-treated phase II mushroom compost. 16S ribosomal deoxyribonucleic acid (rDNA)-based denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) molecular fingerprinting methods were used to track the succession of microbial communities in summer and winter composting cycles. DNA from individual DGGE bands were reamplified and subjected to sequence analysis. Principal component analysis of fingerprints of the composting processes showed intensive changes in bacterial community during the 22-day procedure. Peak temperature samples grouped together and were dominated by Thermus thermophilus. Mature compost patterns were almost identical by both methods (DGGE, T-RFLP). To get an in-depth analysis of the mature compost bacterial community, the sequence data from cultivation of the bacteria and cloning of environmental 16S rDNA were uniquely coupled with the output of the environmental T-RFLP fingerprints (sequence-aided T-RFLP). This method revealed the dominance of a supposedly cellulose-degrading consortium composed of phylotypes related to Pseudoxanthomonas, Thermobifida, and Thermomonospora. © 2008 Springer Science+Business Media, LLC.

  • 30. Tauber, T.
    et al.
    Berta, B.
    Székely, Anna
    Gyarmati, I.
    Kékesi, K.
    Márialigeti, K.
    Tóth, E.
    Characterisation of community structure of bacteria in parallel mesophilic and thermophilic pilot scale anaerobe sludge digesters2007In: Acta Microbiologica et Immunologica Hungarica, ISSN 1588-2640, Vol. 54, no 1, p. 47-55Article in journal (Other academic)
  • 31.
    Vass, Mate
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Lindström, Eva S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Using null models to compare bacterial and microeukaryotic metacommunity assembly under shifting environmental conditionsManuscript (preprint) (Other academic)
  • 32.
    Vass, Mate
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Lindström, Eva S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Using null models to compare bacterial and microeukaryotic metacommunity assembly under shifting environmental conditions2020In: Scientific Reports, E-ISSN 2045-2322, Vol. 10, no 1, p. 1-13, article id 2455Article in journal (Refereed)
    Abstract [en]

    Temporal variations in microbial metacommunity structure and assembly processes in response to shifts in environmental conditions are poorly understood. Hence, we conducted a temporal field study by sampling rock pools in four-day intervals during a 5-week period that included strong changes in environmental conditions due to intensive rain. We characterized bacterial and microeukaryote communities by 16S and 18S rRNA gene sequencing, respectively. Using a suite of null model approaches (elements of metacommunity structure, Raup-Crick beta-diversity and quantitative process estimates) to assess dynamics in community assembly, we found that strong changes in environmental conditions induced small but significant temporal changes in assembly processes and triggered different responses in bacterial and microeukaryotic metacommunities, promoting distinct selection processes. Incidence-based approaches showed that the assemblies of both communities were mainly governed by stochastic processes. In contrast, abundance-based methods indicated the dominance of historical contingency and unmeasured factors in the case of bacteria and microeukaryotes, respectively. We distinguished these processes from dispersal-related processes using additional tests. Regardless of the applied null model, our study highlights that community assembly processes are not static, and the relative importance of different assembly processes can vary under different conditions and between different microbial groups.

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  • 33.
    Vass, Mate
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Szekely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Lindström, Eva S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Osman, Omneya
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Langenheder, Silke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Warming mediates the resistance of aquatic bacteria to invasion during community coalescence2021In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 30, no 5, p. 1345-1356Article in journal (Refereed)
    Abstract [en]

    The immigration history of communities can profoundly affect community composition. For instance, early‐arriving species can have a lasting effect on community structure by reducing the invasion success of late‐arriving ones through priority effects. This can be particularly important when early‐arriving communities coalesce with another community during dispersal (mixing) events. However, the outcome of such community coalescence is unknown as we lack knowledge on how different factors influence the persistence of early‐arriving communities and the invasion success of late‐arriving taxa. Therefore, we implemented a full‐factorial experiment with aquatic bacteria where temperature and dispersal rate of a better adapted community were manipulated to test their joint effects on the resistance of early‐arriving communities to invasion, both at community and population level. Our 16S rRNA gene sequencing‐based results showed that invasion success of better adapted late‐arriving bacteria equaled or even exceeded what we expected based on the dispersal ratios of the recipient and invading communities suggesting limited priority effects on the community level. Patterns detected at the population level, however, showed that resistance of aquatic bacteria to invasion might be strengthened by warming as higher temperatures (a) increased the sum of relative abundances of persistent bacteria in the recipient communities, and (b) restricted the total relative abundance of successfully established late‐arriving bacteria. Warming‐enhanced resistance, however, was not always found and its strengths differed between recipient communities and dispersal rates. Nevertheless, our findings highlight the potential role of warming in mitigating the effects of invasion at the population level.

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    fulltext
  • 34.
    Zhou, Lei
    et al.
    Chinese Acad Sci, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China.;Univ Chinese Acad Sci, Beijing 100049, Peoples R China..
    Zhou, Yongqiang
    Chinese Acad Sci, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China.;Univ Chinese Acad Sci, Beijing 100049, Peoples R China..
    Tang, Xiangming
    Chinese Acad Sci, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China.;Univ Chinese Acad Sci, Beijing 100049, Peoples R China..
    Zhang, Yunlin
    Chinese Acad Sci, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China.;Univ Chinese Acad Sci, Beijing 100049, Peoples R China..
    Jang, Kyoung-Soon
    Korea Basic Sci Inst, Biomed Omics Grp, Cheongju 28119, South Korea..
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Jeppesen, Erik
    Aarhus Univ, Dept Biosci, DK-8600 Silkeborg, Denmark.;Sino Danish Ctr Educ & Res, Beijing 100049, Peoples R China.;Middle East Tech Univ, Dept Biol Sci, Limnol Lab, TR-06800 Ankara, Turkey.;Middle East Tech Univ, Ctr Ecosyst Res & Implementat, TR-06800 Ankara, Turkey.;Middle East Tech Univ, Inst Marine Sci, Mersin, Turkey..
    Resource aromaticity affects bacterial community successions in response to different sources of dissolved organic matter2021In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 190, article id 116776Article in journal (Refereed)
    Abstract [en]

    Microbe-mediated transformation of dissolved organic matter (DOM) contributes substantially to the carbon dynamics and energy flow of aquatic ecosystems; yet, the temporal dynamics of bacterial communities in response to diverse DOM sources are scarcely known. Here, we supplied four distinct sources of DOM (algae-derived, macrophyte-derived, sewage-derived, and soil-derived) to the same bacterial community to track the effects of these DOM sources on the carbon processing and successional dynamics of bacterial communities. Although by the end of the incubation the proportion of bio-degraded DOM was significantly lower in the soil-derived DOM treatment than for the other sources, rapid initial metabolism of protein-like and aliphatic compounds and increasing aromaticity and humification degree of DOM during the incubation period were observed for all sources. The role of stochastic processes in governing the community assembly decreased substantially from 61.4% on the first day to 16.7% at the end of the incubation. Moreover, stronger deterministic selection and lower temporal turnover rate were observed for the soil-derived than the other DOM sources, indicating stronger environmental filtering by the more aromatic DOM. Significant correlations were also observed between the humification index (HIX) of DOM and bacterial community diversities, co-occurrence patterns, habitat niche breadths, and the contribution of deterministic ecological processes. In addition, we demonstrated that taxa with different abundance patterns all play crucial but different roles in the response to DOM variation. Our results indicate the importance of DOM aromaticity as a predictor of the outcome of different DOM sources on bacterial community dynamics.

  • 35.
    Zhou, Lei
    et al.
    Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Zhou, Yongqiang
    Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Tang, Xiangming
    Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Zhang, Yunlin
    Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Zhu, Guangwei
    Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Nanjing, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Székely, Anna J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Jeppesen, Erik
    Aarhus Univ, Dept Biosci, Silkeborg, Denmark.;Sino Danish Ctr Educ & Res, Beijing, Peoples R China.;Middle East Tech Univ, Dept Biol Sci, Limnol Lab, Ankara, Turkey.;Middle East Tech Univ, Ctr Ecosyst Res & Implementat, Ankara, Turkey. Middle East Tech Univ, Inst Marine Sci, Mersin, Turkey..
    Eutrophication alters bacterial co-occurrence networks and increases the importance of chromophoric dissolved organic matter composition2021In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 66, no 6, p. 2319-2332Article in journal (Refereed)
    Abstract [en]

    Eutrophication affects bacterial communities by fueling them with nutrients and carbon sources. While the influence of physicochemical conditions on bacterial communities is well studied, little is known about how dissolved organic matter (DOM) quality affects bacterial interspecific interactions and community composition with increasing eutrophication. Here, we examined the relative importance of physicochemical conditions and chromophoric DOM (CDOM) composition for bacterial community variation across trophic gradients using 109 samples data collected in 33 lakes of the Yangtze-Huaihe River basin. We found a notable increase of bacterial abundance, elevated modularity of co-occurrence networks, and decreased habitat niche breadths from mesotrophic sites to hyper-eutrophic sites, suggesting changes in co-occurrence patterns with eutrophication. Variation partitioning revealed that the proportion purely explained by CDOM composition was higher at the moderate- and hyper-eutrophic sites than at the mesotrophic sites. Moreover, the module structures of the networks correlated significantly with CDOM composition at the eutrophic sites but not at the mesotrophic sites. The significant negative correlation between community-level habitat niche breadths and the intensities of the protein-like components at the moderate- and hyper-eutrophic sites indicates a strong association between biolabile protein-like compounds and habitat specialists in nutrient and substrate enriched lake systems. Our results suggest that consideration of DOM composition can strengthen the identification of links between environmental factors and bacterial community composition and interspecific interactions, especially under resource-rich conditions.

1 - 35 of 35
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