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  • 1.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Abundance data adaptation experiment2017Dataset
  • 2.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Bacterial abundance data from sterilization experiment2017Dataset
  • 3.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Extent and limitations of functional redundancy among bacterial communities towards dissolved organic matter2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    One of the key processes in the carbon cycle on our planet is the degradation of dissolved organic matter (DOM) in aquatic environments. The use of organic matter by bacteria links energy from DOM to higher trophic levels of the ecosystem when bacteria are consumed by other organisms. This is referred to as the microbial loop. In this thesis I examined if the communities were functionally redundant in their ability to utilize organic matter, or if variation in bacterial composition and richness is of importance. To test this overarching question several experiments were conducted that include methods such as illumina sequencing of the 16S rRNA gene for taxonomic identification of bacterial communities, flow cytometry to follow the growth of communities and spectroscopic measurement to describe the composition of the organic matter pool. Initially we demonstrated how to optimally sterilize organic matter for experimental studies in order to preserve its natural complexity. In further experiments we found that bacterial communities are redundant in their utilization of organic matter and can maintain optimal performance towards a range of organic matter pools. Related to this we found that pre-adaptation to organic matter played a small role as communities performed equally well regardless of their environmental history. We saw a small effect of richness and composition of bacterial communities on the efficiency of organic matter use, but conclude that this is of minor importance relative to abiotic factors. Still, we also show that organic matter can put strong selection pressure on bacterial communities with regards to richness and composition. Additionally we found that the supply rate of a carbon compound greatly influenced the energy utilization of the compound, i.e. a higher growth rate can be maintained if substrate is delivered in pulses relative to a continuous flow. Finally we conclude that the variation in bacterial communities is unlikely to have a major influence on carbon cycling in boreal lakes, but to enable a finer understanding, the genetics underlying the carbon utilization needs to be further explored. 

    Delarbeten
    1. Effects of sterilization on dissolved organic carbon (DOC) composition and bacterial utilization of DOC from lakes
    Öppna denna publikation i ny flik eller fönster >>Effects of sterilization on dissolved organic carbon (DOC) composition and bacterial utilization of DOC from lakes
    Visa övriga...
    2018 (Engelska)Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 82, nr 2, s. 199-208Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Sterilization of dissolved organic carbon (DOC) is an essential step in research on interactions between DOC and organisms, for example where the effect of different microbial communities on DOC is studied or vice versa. However, few studies have gone beyond acknowledging that sterilization of DOC influences its characteristics. Here, we aimed to provide further knowledge that enables scientists to better tailor their sterilization methods to their research question. To meet this aim, we conducted a sterilization experiment with DOC from 4 boreal lakes treated with 4 sterilization methods, i.e. 2 filtrations (0.2 µm, 0.1 µm) and 2 autoclaving approaches (single and double autoclaving with a single pH adjustment). Quantity and spectroscopic properties of DOC, before and after sterilization, were studied, and DOC was further tested as a substrate for bacterial growth. We found that the filtration methods better preserved the different DOC measures. In contrast, autoclaving caused major inconsistent shifts in both qualitative and quantitative measures of DOC, as well as an increase of the maximum abundance of bacteria in growth experiments. Nonetheless, there remains a trade-off between retaining the quality of DOC and achieving sterile conditions. Therefore, the sterilization method of choice should be guided by the scientific question at hand.

    Nyckelord
    sterilization, autoclave, filtration, dissolved organic carbon, excitation emission matrices, parallel factor analysis
    Nationell ämneskategori
    Biologiska vetenskaper
    Forskningsämne
    Mikrobiologi
    Identifikatorer
    urn:nbn:se:uu:diva-331676 (URN)10.3354/ame01890 (DOI)000454321300006 ()
    Anmärkning

    Title in Thesis list of papers: Effects of sterilization on composition and bacterial utilization of dissolved organic carbon

    Tillgänglig från: 2017-10-16 Skapad: 2017-10-16 Senast uppdaterad: 2019-12-06Bibliografiskt granskad
    2. Influence of pulsed and continuous substrate inputs on freshwater bacterial community composition and functioning in bioreactors
    Öppna denna publikation i ny flik eller fönster >>Influence of pulsed and continuous substrate inputs on freshwater bacterial community composition and functioning in bioreactors
    Visa övriga...
    2017 (Engelska)Ingår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 19, nr 12, s. 5078-5087Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Aquatic environments are typically not homogenous, but characterized by changing substrate concentration gradients and nutrient patches. This heterogeneity in substrate availability creates a multitude of niches allowing bacteria with different substrate utilization strategies to hypothetically coexist even when competing for the same substrate. To study the impact of heterogeneous distribution of organic substrates on bacterioplankton, bioreactors with freshwater bacterial communities were fed artificial freshwater medium with acetate supplied either continuously or in pulses. After a month-long incubation, bacterial biomass and community-level substrate uptake rates were twice as high in the pulsed treatment compared to the continuously fed reactors even if the same total amount of acetate was supplied to both treatments. The composition of the bacterial communities emerging in the two treatments differed significantly with specific taxa overrepresented in the respective treatments. The higher estimated growth yield in cultures that received pulsed substrate inputs, imply that such conditions enable bacteria to use resources more efficiently for biomass production. This finding agrees with established concepts of basal maintenance energy requirements and high energetic costs to assimilate substrates at low concentration. Our results further imply that degradation of organic matter is influenced by temporal and spatial heterogeneity in substrate availability. 

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-275178 (URN)10.1111/1462-2920.13979 (DOI)000418352800021 ()29124844 (PubMedID)
    Forskningsfinansiär
    Vetenskapsrådet, 2012-3892
    Tillgänglig från: 2016-02-01 Skapad: 2016-02-01 Senast uppdaterad: 2018-01-30Bibliografiskt granskad
    3. Response and effect interactions between bacterial communities and organic matter
    Öppna denna publikation i ny flik eller fönster >>Response and effect interactions between bacterial communities and organic matter
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The interaction between bacteria and dissolved organic matter (DOM) is crucial for the global carbon cycling. Despite decades of research there are, however, few consistent patterns regarding the relationship between bacterial diversity and community composition and DOM. Here we hypothesized that one reason for such inconsistences among studies is that bacterial communities can adapt to a DOM source over time, whereby a change in the functioning of a community can be, at least partly, decoupled from its composition and diversity. To test this idea we performed a reciprocal transplant experiment with medium (i.e. DOM source) and bacterial communities from two boreal lakes. In this experiment the two communities were allowed to adapt to their indigenous and their foreign source of DOM over 42 days. Bacterial community composition (BCC) was measured throughout the experiment. In addition we measured the capacity of the communities to use DOM, in repeated short (5 days) separated bioassays. The results show a response of bacterial community composition to the DOM sources which was influenced by the origin of the community. In contrast, we could not show an effect of BCC on DOM-processing and functional performance. Indeed, communities of different origin processed the two DOM sources equally well even at the beginning of the experiment. This work demonstrates that the DOM pool can be a strong selective force for BCC but not vice versa. 

    Nationell ämneskategori
    Biologiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-331696 (URN)
    Tillgänglig från: 2017-10-17 Skapad: 2017-10-17 Senast uppdaterad: 2017-10-23
    4. The relative importance of richness and BCC for DOC degradation
    Öppna denna publikation i ny flik eller fönster >>The relative importance of richness and BCC for DOC degradation
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The importance of biodiversity has been of primary interest for ecologist the last 20 years, giving rise to biodiversity ecosystem function (BEF) studies. Within the traditional field of ecology reoccurring patterns have emerged but within microbial ecology the importance of species richness for functioning is still poorly understood with few consistent patterns. In this study we examined the effect of species richness for dissolved organic matter degradation in lakes. This was examined within a smaller span of species richness compared to what is typically in microbial BEF experiments. Bacterial communities of reduced species richness were exposed to a range of DOC environments to test if reduced richness changed the functioning of communities and if the effect was similar among DOC environments. This was conducted in a full factorial design of 3 levels, with 6 dilutions, 5 media and 3 inocula resulting in 90 treatments. Overall, richness and community composition appeared to have effects on DOC degradation, but these effects were minor compared to the variation caused by the different DOC sources. Further, the importance of species richness varied among media and, thus, the chemical complexity of the environment influenced the biodiversity-ecosystem functioning relationship. 

    Nationell ämneskategori
    Biologiska vetenskaper
    Forskningsämne
    Mikrobiologi
    Identifikatorer
    urn:nbn:se:uu:diva-331693 (URN)
    Tillgänglig från: 2017-10-17 Skapad: 2017-10-17 Senast uppdaterad: 2017-10-23
  • 4.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Spectroscopic data / carbon quality measurements1987Dataset
  • 5.
    Andersson, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Berga, Mercè
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Lindström, Eva S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Langenheder, Silke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    The spatial structure of bacterial communities is influenced by historical environmental conditions2014Ingår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 95, nr 5, s. 1134-1140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The spatial structure of ecological communities, including that of bacteria, is often influenced by species sorting by contemporary environmental conditions. Moreover, historical processes, i.e., ecological and evolutionary events that have occurred at some point in the past, such as dispersal limitation, drift, priority effects, or selection by past environmental conditions, can be important, but are generally investigated much less. Here, we conducted a field study using 16 rock pools, where we specifically compared the importance of past vs. contemporary environmental conditions for bacterial community structure by correlating present differences in bacterial community composition among pools to environmental conditions measured on the same day, as well as to those measured 2, 4, 6, and 8 d earlier. The results prove that selection by past environmental conditions exists, since we were able to show that bacterial communities are, to a greater extent, an imprint of past compared to contemporary environmental conditions. We suggest that this is the result of a combination of different mechanisms, including priority effects that cause rapid adaptation to new environmental conditions of taxa that have been initially selected by past environmental conditions, and slower rates of turnover in community composition compared to environmental conditions.

  • 6.
    Andersson, Martin G. I.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Catalán, Núria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi. ICRA, Catalan Institute of Water Research, Girona, Spain.
    Rahman, Zeeshanur
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi. Applied Microbiology and Biotechnology Laboratory, Department of Botany, University of Delhi.
    Tranvik, Lars J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Lindström, Eva S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Effects of sterilization on dissolved organic carbon (DOC) composition and bacterial utilization of DOC from lakes2018Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 82, nr 2, s. 199-208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sterilization of dissolved organic carbon (DOC) is an essential step in research on interactions between DOC and organisms, for example where the effect of different microbial communities on DOC is studied or vice versa. However, few studies have gone beyond acknowledging that sterilization of DOC influences its characteristics. Here, we aimed to provide further knowledge that enables scientists to better tailor their sterilization methods to their research question. To meet this aim, we conducted a sterilization experiment with DOC from 4 boreal lakes treated with 4 sterilization methods, i.e. 2 filtrations (0.2 µm, 0.1 µm) and 2 autoclaving approaches (single and double autoclaving with a single pH adjustment). Quantity and spectroscopic properties of DOC, before and after sterilization, were studied, and DOC was further tested as a substrate for bacterial growth. We found that the filtration methods better preserved the different DOC measures. In contrast, autoclaving caused major inconsistent shifts in both qualitative and quantitative measures of DOC, as well as an increase of the maximum abundance of bacteria in growth experiments. Nonetheless, there remains a trade-off between retaining the quality of DOC and achieving sterile conditions. Therefore, the sterilization method of choice should be guided by the scientific question at hand.

  • 7.
    Lindström, Eva S.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Effects of sterilization on composition and bacterial utilization of dissolved organic carbon2017Dataset
  • 8.
    Lindström, Eva S.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Effects of sterilization on composition and bacterial utilization of dissolved organic carbon2017Dataset
  • 9.
    Onuţ-Brännström, Ioana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Systematisk biologi.
    Benjamin, Mitchell
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Systematisk biologi.
    Scofield, Douglas G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Starri, Heiðmarsson
    Icelandic Institute of Natural History, Borgir Nordurslod, Iceland.
    Andersson, Martin G.I.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Lindström, Eva S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Johannesson, Hanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Systematisk biologi.
    Sharing of photobionts in sympatric populations of Thamnolia and Cetraria lichens: evidence from high-throughput sequencing2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 4406Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we explored the diversity of green algal symbionts (photobionts) in sympatric populations of the cosmopolitan lichen-forming fungi Thamnolia and Cetraria. We sequenced with both Sanger and Ion Torrent High-Throughput Sequencing technologies the photobiont ITS-region of 30 lichen thalli from two islands: Iceland and Öland. While Sanger recovered just one photobiont genotype from each thallus, the Ion Torrent data recovered 10–18 OTUs for each pool of 5 lichen thalli, suggesting that individual lichens can contain heterogeneous photobiont populations. Both methods showed evidence for photobiont sharing between Thamnolia and Cetraria on Iceland. In contrast, our data suggest that on Öland the two mycobionts associate with distinct photobiont communities, with few shared OTUs revealed by Ion Torrent sequencing. Furthermore, by comparing our sequences with public data, we identified closely related photobionts from geographically distant localities. Taken together, we suggest that the photobiont composition in Thamnolia and Cetraria results from both photobiont-mycobiont codispersal and local acquisition during mycobiont establishment and/or lichen growth. We hypothesize that this is a successful strategy for lichens to be flexible in the use of the most adapted photobiont for the environment.

  • 10.
    Ricão Canelhas, Monica
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi. eDNA Solut Ltd, Bjorkasgatan 16, S-43131 Molndal, Sweden.
    Andersson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi. eDNA Solut Ltd, Bjorkasgatan 16, S-43131 Molndal, Sweden.
    Eiler, Alexander
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Lindström, Eva S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Bertilsson, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Influence of pulsed and continuous substrate inputs on freshwater bacterial community composition and functioning in bioreactors2017Ingår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 19, nr 12, s. 5078-5087Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aquatic environments are typically not homogenous, but characterized by changing substrate concentration gradients and nutrient patches. This heterogeneity in substrate availability creates a multitude of niches allowing bacteria with different substrate utilization strategies to hypothetically coexist even when competing for the same substrate. To study the impact of heterogeneous distribution of organic substrates on bacterioplankton, bioreactors with freshwater bacterial communities were fed artificial freshwater medium with acetate supplied either continuously or in pulses. After a month-long incubation, bacterial biomass and community-level substrate uptake rates were twice as high in the pulsed treatment compared to the continuously fed reactors even if the same total amount of acetate was supplied to both treatments. The composition of the bacterial communities emerging in the two treatments differed significantly with specific taxa overrepresented in the respective treatments. The higher estimated growth yield in cultures that received pulsed substrate inputs, imply that such conditions enable bacteria to use resources more efficiently for biomass production. This finding agrees with established concepts of basal maintenance energy requirements and high energetic costs to assimilate substrates at low concentration. Our results further imply that degradation of organic matter is influenced by temporal and spatial heterogeneity in substrate availability. 

1 - 10 av 10
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