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  • 351.
    Logue, Jürg Brendan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Empirical approaches to metacommunities: a review and comparison with theoryManuscript (preprint) (Other academic)
    Abstract [en]

    Metacommunity theory has advanced our understanding of how spatial dynamics and local interactions shape local community structure and biodiversity. The last decade has seen an increase in implementation of these ideas in empirical ecology to explain and understand the regulation of local community structure and dynamics. Here, we review the different empirical (experimental and observational) approaches to metacommunities to analyse their strengths and weaknesses in comparison to natural ecosystems and theoretical paradigms. Experimental approaches are extremely diverse, ranging from highly controlled laboratory microcosms to large-scale fragmentation studies in the field. The main body of experiments, however, favours downscaled, artificial designs, avoiding physical complexity. These approaches are often successful in mechanistically addressing local and regional species interactions but the preponderance of artificial dispersal treatments via transfer neglects the importance of species’ differences in dispersal ability for community structure. Observational approaches mainly focus on investigating smaller organisms in aquatic communities, which are predominantly assembled by local environmental processes. However, observational approaches often lack actual measurements of dispersal rates, which hamper the distinction of local and regional effects on community composition. More generally, empirical metacommunity data deviate from theory as – with the exception of the most artificial experimental systems – the data rarely reflect specific paradigms. Thus, the paradigms capture only parts of the observed spatial dynamics. Metacommunity theory has emerged as a highly successful framework to understand the assembly of local communities but we conclude that empirical and theoretical approaches need thorough harmonisation to utilise the potential of this framework in guiding our understanding of spatial dynamics in ecological communities.

  • 352.
    Logue, Jürg Brendan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Factors influencing the biogeography of bacteria in fresh waters - a metacommunity approach2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of ecology’s primary goals is to comprehend biodiversity and its patterns of distribution over space and time. Since microorganisms play a pivotal role in key ecological processes, the diversity of microbial communities may have important implications for the stability and functioning of Earth’s ecosystems. Thus, it is of utmost importance to develop a theoretical foundation but also a conceptual understanding for the mechanisms that generate and maintain microbial diversity.

    The aim of this thesis is to investigate to what extent local freshwater bacterioplankton diversity, i.e. richness and community composition, is structured by local environmental interactions and/or regional processes. The key objective is to identify ecological linkages between lake bacterioplankton and bacterial communities in connected streams and the surrounding terrestrial landscape, thereby applying a metacommunity approach. To do so, I studied several natural lake bacterioplankton assemblies within different regions of Sweden and assessed both local environmental properties and regional parameters (e.g. dispersal, landscape position). The genetic composition of freshwater bacterioplankton diversity was determined by means of terminal-restriction fragment length polymorphism or 454 pyrosequencing.

    From the review on the biogeography of bacterioplankton in inland waters it became clear that microbial diversity and its spatial distribution are governed by a complex interplay of both local and regional drivers. In one case, freshwater bacterioplankton communities were structured by local environmental conditions rather than by regional dispersal processes. These local environmental conditions seemed to be equally important in controlling both the total bacterioplankton community and its active fraction. In a study of bacterioplankton communities from five different regions, locally abundant aquatic bacteria were shown to be also regionally widespread, a pattern predicted by neutral theory. Yet, this degree of similarity decreased with increasing environmental heterogeneity. In another study, bacterioplankton richness was controlled mostly by nutrient content, indicating that productivity exerted influence on bacterioplankton richness. However, landscape position and productivity covaried, suggesting that the landscape dictates environmental properties, which then directly structure local bacterioplankton richness. Finally, a review synthesising results from empirical metacommunity approaches and comparing these to theory showed that yet a gap between empirics and theory exists. To conclude, local bacterioplankton diversity appeared to be mainly structured by local environmental properties. However, signatures of neutral processes driving local bacterioplankton community assembly were also recorded.

    List of papers
    1. Biogeography of bacterioplankton in inland waters.
    Open this publication in new window or tab >>Biogeography of bacterioplankton in inland waters.
    2008 (English)In: Freshwater Reviews, ISSN 1755-084X, E-ISSN 1755-084X, Vol. 1, no 1, p. 99-114Article in journal (Refereed) Published
    Abstract [en]

    Bacteria are among the most abundant groups of organisms.  They mediate key ecological processes.  Recent molecular advances have provided greater insight into bacterial diversity as well as allowing a more thorough examination of patterns in the spatial and temporal distribution of bacteria.  Thus, the study of bacterial biodiversity and biogeographical distribution has stimulated considerable interest and dispute over the last decade. This review summarises the findings obtained from studies on the biogeography of bacterioplankton in inland waters.  We examine factors and processes that may determine and maintain bacterial diversity and biogeography, and relate these to the theoretical metacommunity framework. We conclude that the importance of local environmental factors (such as lake character) for local bacterioplankton community compositions (BCC) is much more intensively studied than the importance of regional factors, such as dispersal.  Further, few attempts have been made to evaluate simultaneously the relative importance of the two types of factors for BCC.  Finally, we summarise gaps in knowledge, delineate challenges and put forward possible future research directions.

    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-107690 (URN)10.1608/FRJ-1.1.9 (DOI)
    Available from: 2009-08-24 Created: 2009-08-24 Last updated: 2017-12-13
    2. Empirical approaches to metacommunities: a review and comparison with theory
    Open this publication in new window or tab >>Empirical approaches to metacommunities: a review and comparison with theory
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Metacommunity theory has advanced our understanding of how spatial dynamics and local interactions shape local community structure and biodiversity. The last decade has seen an increase in implementation of these ideas in empirical ecology to explain and understand the regulation of local community structure and dynamics. Here, we review the different empirical (experimental and observational) approaches to metacommunities to analyse their strengths and weaknesses in comparison to natural ecosystems and theoretical paradigms. Experimental approaches are extremely diverse, ranging from highly controlled laboratory microcosms to large-scale fragmentation studies in the field. The main body of experiments, however, favours downscaled, artificial designs, avoiding physical complexity. These approaches are often successful in mechanistically addressing local and regional species interactions but the preponderance of artificial dispersal treatments via transfer neglects the importance of species’ differences in dispersal ability for community structure. Observational approaches mainly focus on investigating smaller organisms in aquatic communities, which are predominantly assembled by local environmental processes. However, observational approaches often lack actual measurements of dispersal rates, which hamper the distinction of local and regional effects on community composition. More generally, empirical metacommunity data deviate from theory as – with the exception of the most artificial experimental systems – the data rarely reflect specific paradigms. Thus, the paradigms capture only parts of the observed spatial dynamics. Metacommunity theory has emerged as a highly successful framework to understand the assembly of local communities but we conclude that empirical and theoretical approaches need thorough harmonisation to utilise the potential of this framework in guiding our understanding of spatial dynamics in ecological communities.

    Keywords
    metacommunity, community ecology, experimental, observational, empirical, theory, review, literature survey
    National Category
    Biological Sciences
    Research subject
    Biology
    Identifiers
    urn:nbn:se:uu:diva-129366 (URN)
    Available from: 2010-08-12 Created: 2010-08-12 Last updated: 2011-11-15
    3. Species sorting affects bacterioplankton community composition as determined by 16S rDNA and 16S rRNA fingerprints
    Open this publication in new window or tab >>Species sorting affects bacterioplankton community composition as determined by 16S rDNA and 16S rRNA fingerprints
    2010 (English)In: The ISME Journal, ISSN 1751-7362, Vol. 4, no 6, p. 729-738Article in journal (Refereed) Published
    Abstract [en]

    To understand the mechanisms determining community composition, it is essential to distinctively unravel the importance of local from that of regional processes. In this effort, the mechanisms underlying bacterioplankton community assembly were analysed in eight lakes of short water residence time (WRT) during a four-season sampling campaign. Bacterioplankton community composition (BCC) was determined using terminal-restriction fragment length polymorphism (t-RFLP) on the 16S rRNA gene (16S rDNA) and 16S rRNA. The relationship between similarity in BCC between a lake and its major inlet on the one hand and cell import per cell production rate from the inlet to the lake epilimnion on the other was used as a measure of the importance of cell dispersal (mass effects) for community assembly. Low similarities in BCC between lakes and their inlets were observed even at short WRTs, and the degree of similarity correlated better with the environmental conditions in lakes and streams than with cell import per cell production rates. Thus, mass effects seemed less important for local lake BCC in comparison to environmental habitat characteristics (species sorting). Analyses of 16S rDNA and 16S rRNA community fingerprints yielded similar results, indicating that species-sorting dynamics exerted an equally important effect on both the abundant and active fraction within the studied bacterioplankton communities.

    Place, publisher, year, edition, pages
    Nature Publishing Group, 2010
    Keywords
    16S rDNA, 16S rRNA, biogeography, mass effects, metacommunity, species sorting
    National Category
    Biological Sciences
    Research subject
    Biology with specialization in Limnology
    Identifiers
    urn:nbn:se:uu:diva-129364 (URN)10.1038/ismej.2009.156 (DOI)000278104800002 ()20130658 (PubMedID)
    Available from: 2010-08-12 Created: 2010-08-12 Last updated: 2010-12-13Bibliographically approved
    4. Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species-area relationships
    Open this publication in new window or tab >>Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species-area relationships
    Show others...
    2012 (English)In: The ISME Journal, ISSN 1751-7362, Vol. 6, no 6, p. 1127-1136Article in journal (Refereed) Published
    Abstract [en]

    A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 22 669 sequences per lake showed that freshwater BR in fourteen nutrient-poor lakes was positively influenced by nutrient availability. Our study is, thus, consistent with the finding that the supply of available nutrients is a major driver of species richness; a pattern that may well be universally valid to the world of both micro- and macro-organisms. We, furthermore, observed that BR increased with elevated landscape position, most likely as a consequence of differences in nutrient availability. Finally, BR decreased with increasing lake and catchment area that is negative species-area relationships (SARs) were recorded; a finding that re-opens the debate about whether positive SARs can indeed be found in the microbial world and whether positive SARs can in fact be pronounced as one of the few “laws” in ecology.

    Keywords
    bacterial richness, biogeography, freshwater, landscape position, productivity, species-area relationship
    National Category
    Microbiology Ecology
    Research subject
    Biology with specialization in Limnology
    Identifiers
    urn:nbn:se:uu:diva-130008 (URN)10.1038/ismej.2011.184 (DOI)000304047800005 ()
    Available from: 2010-08-26 Created: 2010-08-26 Last updated: 2013-01-14Bibliographically approved
    5. Regional invariance among microbial communities
    Open this publication in new window or tab >>Regional invariance among microbial communities
    Show others...
    2010 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 13, no 1, p. 118-127Article in journal (Refereed) Published
    Abstract [en]

    Microbial ecology has focused much on causes of between-site variation in community composition. By analysing five data-sets each of aquatic bacteria and phytoplankton, we demonstrated that microbial communities show a large degree of similarity in community composition and that abundant taxa were widespread, a typical pattern for many metazoan metacommunities. The regional abundance of taxa explained on average 85 and 41% of variation in detection frequency and 58 and 31% of variation in local abundances for bacteria and phytoplankton, respectively. However, regional abundance explained less variation in local abundances with increasing environmental variation between sites within data-sets. These findings indicate that the studies of microbial assemblages need to consider similarities between communities to better understand the processes underlying the assembly of microbial communities. Finally, we propose that the degree of regional invariance can be linked to the evolution of microbes and the variation in ecosystem functions performed by microbial communities.

    Keywords
    Abundance-occupancy, dispersal, freshwater, generalists, neutral models, species sorting, Sweden
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-121206 (URN)10.1111/j.1461-0248.2009.01413.x (DOI)000272996200013 ()19968693 (PubMedID)
    Available from: 2010-03-19 Created: 2010-03-19 Last updated: 2017-12-12Bibliographically approved
  • 353.
    Logue, Jürg Brendan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Bürgmann, Helmut
    Robinson, Christopher T.
    Progress in the Ecological Genetics and Biodiversity of Freshwater Bacteria2008In: BioScience, ISSN 0006-3568, E-ISSN 1525-3244, Vol. 58, no 2, p. 103-113Article in journal (Refereed)
    Abstract [en]

    The field of microbial ecology has grown tremendously with the advent of novel molecular techniques, allowing the study of uncultured microbes in the environment, and producing a paradigm shift: now, rather than using bacteria cultures for evaluating cell-specific questions, researchers use RNA and DNA techniques to examine more broad-based ecological and evolutionary constructs such as biogeography and the long-debated biological species concept. Recent work has begun to relate bacteria functional genes to ecosystem processes and functioning, thereby enabling a better understanding of the interactive role of bacteria in different and often-changing environments. The field continues to mature and will most likely make substantial contributions in the future with additional efforts that include metagenomics and genomics. Here we review progress in the application of molecular techniques to study microbial communities in freshwater environments.

  • 354.
    Logue, Jürg Brendan
    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.
    Andersson, Anders F.
    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.
    Drakare, Stina
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU).
    Lanzén, Anders
    Centre for Geobiology and Department of Biology, University of Bergen.
    Lindström, Eva S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species-area relationships2012In: The ISME Journal, ISSN 1751-7362, Vol. 6, no 6, p. 1127-1136Article in journal (Refereed)
    Abstract [en]

    A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 22 669 sequences per lake showed that freshwater BR in fourteen nutrient-poor lakes was positively influenced by nutrient availability. Our study is, thus, consistent with the finding that the supply of available nutrients is a major driver of species richness; a pattern that may well be universally valid to the world of both micro- and macro-organisms. We, furthermore, observed that BR increased with elevated landscape position, most likely as a consequence of differences in nutrient availability. Finally, BR decreased with increasing lake and catchment area that is negative species-area relationships (SARs) were recorded; a finding that re-opens the debate about whether positive SARs can indeed be found in the microbial world and whether positive SARs can in fact be pronounced as one of the few “laws” in ecology.

  • 355.
    Logue, Jürg Brendan
    et al.
    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.
    Biogeography of bacterioplankton in inland waters.2008In: Freshwater Reviews, ISSN 1755-084X, E-ISSN 1755-084X, Vol. 1, no 1, p. 99-114Article in journal (Refereed)
    Abstract [en]

    Bacteria are among the most abundant groups of organisms.  They mediate key ecological processes.  Recent molecular advances have provided greater insight into bacterial diversity as well as allowing a more thorough examination of patterns in the spatial and temporal distribution of bacteria.  Thus, the study of bacterial biodiversity and biogeographical distribution has stimulated considerable interest and dispute over the last decade. This review summarises the findings obtained from studies on the biogeography of bacterioplankton in inland waters.  We examine factors and processes that may determine and maintain bacterial diversity and biogeography, and relate these to the theoretical metacommunity framework. We conclude that the importance of local environmental factors (such as lake character) for local bacterioplankton community compositions (BCC) is much more intensively studied than the importance of regional factors, such as dispersal.  Further, few attempts have been made to evaluate simultaneously the relative importance of the two types of factors for BCC.  Finally, we summarise gaps in knowledge, delineate challenges and put forward possible future research directions.

  • 356.
    Logue, Jürg Brendan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Mouquet, Nicolas
    Peter, Hannes
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Hillebrand, Helmut
    Empirical approaches to metacommunities: a review and comparison with theory2011In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 26, no 9, p. 482-491Article in journal (Refereed)
    Abstract [en]

    Metacommunity theory has advanced understanding of how spatial dynamics and local interactions shape community structure and biodiversity. Here, we review empirical approaches to metacommunities, both observational and experimental, pertaining to how well they relate to and test theoretical metacommunity paradigms and how well they capture the realities of natural ecosystems. First, we show that the species-sorting and mass-effects paradigms are the most commonly tested and supported paradigms. Second, the dynamics observed can often be ascribed to two or more of the four non-exclusive paradigms. Third, empirical approaches relate only weakly to the concise assumptions and predictions made by the paradigms. Consequently, we suggest major avenues of improvement for empirical metacommunity approaches, including the integration across theoretical approaches and the incorporation of evolutionary and meta-ecosystem dynamics. We hope for metacommunity ecology to thereby bridge existing gaps between empirical and theoretical work, thus becoming a more powerful framework to understand dynamics across ecosystems.

  • 357.
    Lopez-Fernandez, Margarita
    et al.
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Kalmar, Sweden;Helmholtz Zentrum Dresden Rossendorf, Inst Resource Ecol, Dresden, Germany.
    Broman, Elias
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Kalmar, Sweden;Stockholm Univ, Dept Ecol Environm & Plant Sci, Stockholm, Sweden.
    Simone, Domenico
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Kalmar, Sweden;Swedish Univ Agr Sci, SLU Bioinformat Infrastruct, Uppsala, Sweden.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala Univ, Limnol & Sci Life Lab, Dept Ecol & Genet, Uppsala, Sweden;Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden.
    Dopson, Mark
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Kalmar, Sweden.
    Statistical Analysis of Community RNA Transcripts between Organic Carbon and Geogas-Fed Continental Deep Biosphere Groundwaters2019In: mBio, ISSN 2161-2129, E-ISSN 2150-7511, Vol. 10, no 4, article id e01470-19Article in journal (Refereed)
    Abstract [en]

    Life in water-filled bedrock fissures in the continental deep biosphere is broadly constrained by energy and nutrient availability. Although these communities are alive, robust studies comparing active populations and metabolic processes across deep aquifers are lacking. This study analyzed three oligotrophic Fennoscandian Shield groundwaters, two "modern marine" waters that are replenished with organic carbon from the Baltic Sea and are likely less than 20 years old (171.3 and 415.4 m below sea level) and an extremely oligotrophic "thoroughly mixed" water (448.8 m below sea level) of unknown age that is composed of very old saline and marine waters. Cells were captured either using a sampling device that rapidly fixed RNA under in situ conditions or by filtering flowing groundwater over an extended period before fixation. Comparison of metatranscriptomes between the methods showed statistically similar transcript profiles for the respective water types, and they were analyzed as biological replicates. Study of the small subunit (SSU) rRNA confirmed active populations from all three domains of life, with many potentially novel unclassified populations present. Statistically supported differences between communities included heterotrophic sulfate-reducing bacteria in the modern marine water at 171.3 m below sea level that has a higher organic carbon content than do largely autotrophic populations in the H-2- and CO2-fed thoroughly mixed water. While this modern marine water had signatures of methanogenesis, syntrophic populations were predominantly in the thoroughly mixed water. The study provides a first statistical evaluation of differences in the active microbial communities in groundwaters differentially fed by organic carbon or "geogases." IMPORTANCE Despite being separated from the photosynthesis-driven surface by both distance and time, the deep biosphere is an important driver for the earth's carbon and energy cycles. However, due to the difficulties in gaining access and low cell numbers, robust statistical omits studies have not been carried out, and this limits the conclusions that can be drawn. This study benchmarks the use of two separate sampling systems and demonstrates that they provide statistically similar RNA transcript profiles, importantly validating several previously published studies. The generated data are analyzed to identify statistically valid differences in active microbial community members and metabolic processes. The results highlight contrasting taxa and growth strategies in the modern marine waters that are influenced by recent infiltration of Baltic Sea water versus the hydrogen- and carbon dioxide-fed, extremely oligotrophic, thoroughly mixed water.

  • 358.
    Lopez-Fernandez, Margarita
    et al.
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Barlastgatan 11, Kalmar, Sweden.;Helmholtz Zentrum Dresden Rossendorf, Inst Resource Ecol, Bautzner Landstr 400, D-01328 Dresden, Germany..
    Broman, Elias
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Barlastgatan 11, Kalmar, Sweden..
    Turner, Stephanie
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Barlastgatan 11, Kalmar, Sweden..
    Wu, Xiaofen
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Barlastgatan 11, Kalmar, Sweden.;Univ Copenhagen, Dept Biol, Copenhagen, Denmark..
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dopson, Mark
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst EEMiS, Barlastgatan 11, Kalmar, Sweden..
    Investigation of viable taxa in the deep terrestrial biosphere suggests high rates of nutrient recycling2018In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 94, no 8, article id fiy121Article in journal (Refereed)
    Abstract [en]

    The deep biosphere is the largest 'bioreactor' on earth, and microbes inhabiting this biome profoundly influence global nutrient and energy cycles. An important question for deep biosphere microbiology is whether or not specific populations are viable. To address this, we used quantitative PCR and high throughput 16S rRNA gene sequencing of total and viable cells (i.e. with an intact cellular membrane) from three groundwaters with different ages and chemical constituents. There were no statistically significant differences in 16S rRNA gene abundances and microbial diversity between total and viable communities. This suggests that populations were adapted to prevailing oligo trophic conditions and that non-viable cells are rapidly degraded and recycled into new biomass. With higher concentrations of organic carbon, the modem marine and undefined mixed waters hosted a community with a larger range of predicted growth strategies than the ultra-oligo trophic old saline water. These strategies included fermentative and potentially symbiotic lifestyles by candidate phyla that typically have streamlined genomes. In contrast, the old saline waters had more 16S rRNA gene sequences in previously cultured lineages able to oxidize hydrogen and fix carbon dioxide. This matches the paradigm of a hydrogen and carbon dioxide-fed chemolithoauto trophic deep biosphere.

  • 359. Lopez-Fernandez, Margarita
    et al.
    Simone, Domenico
    Wu, Xiaofen
    Soler, Lucile
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Nilsson, Emelie
    Holmfeldt, Karin
    Lantz, Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dopson, Mark
    Metatranscriptomes Reveal That All Three Domains of Life Are Active but Are Dominated by Bacteria in the Fennoscandian Crystalline Granitic Continental Deep Biosphere2018In: mBio, ISSN 2161-2129, E-ISSN 2150-7511, Vol. 9, no 6, article id e01792-18Article in journal (Refereed)
    Abstract [en]

    The continental subsurface is suggested to contain a significant part of the earth's total biomass. However, due to the difficulty of sampling, the deep subsurface is still one of the least understood ecosystems. Therefore, microorganisms inhabiting this environment might profoundly influence the global nutrient and energy cycles. In this study, in situ fixed RNA transcripts from two deep continental groundwaters from the Äspö Hard Rock Laboratory (a Baltic Sea-influenced water with a residence time of <20 years, defined as "modern marine," and an "old saline" groundwater with a residence time of thousands of years) were subjected to metatranscriptome sequencing. Although small subunit (SSU) rRNA gene and mRNA transcripts aligned to all three domains of life, supporting activity within these community subsets, the data also suggested that the groundwaters were dominated by bacteria. Many of the SSU rRNA transcripts grouped within newly described candidate phyla or could not be mapped to known branches on the tree of life, suggesting that a large portion of the active biota in the deep biosphere remains unexplored. Despite the extremely oligotrophic conditions, mRNA transcripts revealed a diverse range of metabolic strategies that were carried out by multiple taxa in the modern marine water that is fed by organic carbon from the surface. In contrast, the carbon dioxide- and hydrogen-fed old saline water with a residence time of thousands of years predominantly showed the potential to carry out translation. This suggested these cells were active, but waiting until an energy source episodically becomes available.IMPORTANCE A newly designed sampling apparatus was used to fix RNA under in situ conditions in the deep continental biosphere and benchmarks a strategy for deep biosphere metatranscriptomic sequencing. This apparatus enabled the identification of active community members and the processes they carry out in this extremely oligotrophic environment. This work presents for the first time evidence of eukaryotic, archaeal, and bacterial activity in two deep subsurface crystalline rock groundwaters from the Äspö Hard Rock Laboratory with different depths and geochemical characteristics. The findings highlight differences between organic carbon-fed shallow communities and carbon dioxide- and hydrogen-fed old saline waters. In addition, the data reveal a large portion of uncharacterized microorganisms, as well as the important role of candidate phyla in the deep biosphere, but also the disparity in microbial diversity when using standard microbial 16S rRNA gene amplification versus the large unknown portion of the community identified with unbiased metatranscriptomes.

  • 360.
    Lopez-Fernandez, Margarita
    et al.
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, Kalmar, Sweden.
    Åström, Mats
    Linnaeus Univ, Dept Biol & Environm Sci, Kalmar, Sweden.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Dopson, Mark
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, Kalmar, Sweden.
    Depth and Dissolved Organic Carbon Shape Microbial Communities in Surface Influenced but Not Ancient Saline Terrestrial Aquifers2018In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, article id 2880Article in journal (Refereed)
    Abstract [en]

    The continental deep biosphere is suggested to contain a substantial fraction of the earth’s total biomass and microorganisms inhabiting this environment likely have a substantial impact on biogeochemical cycles. However, the deep microbial community is still largely unknown and can be influenced by parameters such as temperature, pressure, water residence times, and chemistry of the waters. In this study, 21 boreholes representing a range of deep continental groundwaters from the Äspö Hard Rock Laboratory were subjected to high-throughput 16S rRNA gene sequencing to characterize how the different water types influence the microbial communities. Geochemical parameters showed the stability of the waters and allowed their classification into three groups. These were (i) waters influenced by infiltration from the Baltic Sea with a “modern marine (MM)” signature, (ii) a “thoroughly mixed (TM)” water containing groundwaters of several origins, and (iii) deep “old saline (OS)” waters. Decreasing microbial cell numbers positively correlated with depth. In addition, there was a stronger positive correlation between increased cell numbers and dissolved organic carbon for the MM compared to the OS waters. This supported that the MM waters depend on organic carbon infiltration from the Baltic Sea while the ancient saline waters were fed by “geogases” such as carbon dioxide and hydrogen. The 16S rRNA gene relative abundance of the studied groundwaters revealed different microbial community compositions. Interestingly, the TM water showed the highest dissimilarity compared to the other two water types, potentially due to the several contrasting water types contributing to this groundwater. The main identified microbial phyla in the groundwaters were Gammaproteobacteria, unclassified sequences, Campylobacterota (formerly Epsilonproteobacteria), Patescibacteria, Deltaproteobacteria, and Alphaproteobacteria. Many of these taxa are suggested to mediate ferric iron and nitrate reduction, especially in the MM waters. This indicated that nitrate reduction may be a neglected but important process in the deep continental biosphere. In addition to the high number of unclassified sequences, almost 50% of the identified phyla were archaeal or bacterial candidate phyla. The percentage of unknown and candidate phyla increased with depth, pointing to the importance and necessity of further studies to characterize deep biosphere microbial populations.

  • 361. Lundin, Daniel
    et al.
    Severin, Ina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Logue, Jürg Brendan
    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.
    Andersson, Anders F
    Lindström, Eva S
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Which sequencing depth is sufficient to describe patterns in bacterial a- and b-diversity?2012In: Environmental Microbiology Reports, ISSN 1758-2229, E-ISSN 1758-2229, Vol. 4, no 3, p. 367-372Article in journal (Refereed)
    Abstract [en]

    The vastness of microbial diversity implies that an almost infinite number of individuals needs to be identified to accurately describe such communities. Practical and economical constraints may therefore prevent appropriate study designs. However, for many questions in ecology it is not essential to know the actual diversity but rather the trends among samples thereof. It is, hence, important to know to what depth microbial communities need to be sampled to accurately measure trends in diversity. We used three data sets of freshwater and sediment bacteria, where diversity was explored using 454 pyrosequencing. Each data set contained 6–15 communities from which 15 000–20 000 16S rRNA gene sequences each were obtained. These data sets were subsampled repeatedly to 10 different depths down to 200 sequences per community. Diversity estimates varied with sequencing depth, yet, trends in diversity among samples were less sensitive. We found that 1000 denoised sequences per sample explained to 90% the trends in β-diversity (Bray-Curtis index) among samples observed for 15 000–20 000 sequences. Similarly, 5000 denoised sequences were sufficient to describe trends in α-diversity (Shannon index) with the same accuracy. Further, 5000 denoised sequences captured to more than 80% the trends in Chao1 richness and Pielou's evenness.

  • 362. Lundqvist, Anna
    et al.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Goedkoop, Willem
    Interactions with DOM and biofilms affect the fate and bioavailability of insecticides to invertebrate grazers2012In: Ecotoxicology, ISSN 0963-9292, E-ISSN 1573-3017, Vol. 21, no 8, p. 2398-2408Article in journal (Refereed)
    Abstract [en]

    We studied the fate and bioavailability of insecticides in short-term experiments (48 h) with different hydrophobicity (3.8 pM carbofuran, 3.0 pM lindane, and 5.3 pM chlorpyrifos) across gradients in dissolved organic matter (low-, medium-, and high-DOM) in freshwater microcosms, mimicking runoff events of pesticides. The effects of biofilms were studied by including treatments with biofilms cultivated under different DOM-concentrations. The presence of biofilms negatively affected chlorpyrifos water concentrations, indicating rapid sorption of this hydrophobic pesticide, while lindane concentrations instead increased and carbofuran concentrations were unaffected. Associations of lindane and chlorpyrifos with biofilms were 1.6-2.0 times higher in low- and high-DOM than in medium-DOM treatments, indicating that sorption was affected not only by the quantity, but also by the quality of DOM. Although the proportion of pesticides recovered in biofilms was consistently less than 1 % of added pesticide, pesticide concentrations in biofilms were on average more than 75- (carbofuran) and 382-times (lindane) higher than those in water. Snail accumulation of all three pesticides was significantly affected by DOMconcentrations and correlated to pesticide hydrophobicity, but the relationships were not straightforward. For example, carbofuran uptake in treatments without biofilms was higher in low-DOM than in medium- and high-DOM treatments, while chlorpyrifos uptake instead increased across the DOM-gradient. Biofilms played a role only for the uptake of chlorpyrifos, which decreased markedly in the presence of biofilms. Bioconcentration factors (BCF) calculated for snails and biofilms differed for the three pesticides and were related to their sorption behaviour (i.e., hydrophobicity). The relative proportion of pesticide uptake through biofilm consumption was consistently less than 2 %, showing that passive uptake was by far the predominant uptake pathway for all three pesticides.

  • 363.
    Lymer, David
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Logue, Jürg Brendan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Brussaard, Corina P. D.
    Baudoux, Anne-Claire
    Vrede, Katarina
    Lindström, Eva
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Temporal variation in freshwater viral and bacterial community composition2008In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 53, no 6, p. 1163-1175Article in journal (Refereed)
    Abstract [en]

    1. The goal of this study conducted in three lakes differing in nutrient content and size was to assess the temporal variation in viral community composition and possible co-variation with compositional changes in bacterial communities.   

    2. The viral community composition differed among lakes and changed over the season. Changes could also be detected on short-time scales, i.e. over a few days. These changes were comparable in magnitude to the changes detected between months or seasons.   

    3. The most important environmental factors co-varying with viral community composition, as determined by multivariate analysis, differed over the year and among lakes. Temperature and concentrations of dissolved organic carbon (DOC), total phosphorus and soluble reactive phosphorus were the most important factors.

    4. Bacterial community composition also varied over the season and among lakes. The most important factors co-varying with bacterial community composition, as determined by multivariate analysis, were also temperature and DOC concentration.

    5. Correlation between viral and bacterial community composition was weak and appeared to be a result of an indirect connection rather than a direct relationship between bacteria and viruses.

  • 364.
    Lönnstedt, Oona
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Frisch, Achley J.
    Habitat bleaching disrupts threat responses and persistence in anemonefish2014In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 517, p. 265-270Article in journal (Refereed)
    Abstract [en]

    Climate-induced habitat bleaching is linked to dramatic declines in diversity and abundance of coral reef fish; however, mechanisms underlying these declines are poorly understood. Here, we used in situ studies to demonstrate that bleaching can influence persistence of reef fish by affecting behaviours, including responses to a potential predation threat. When encountering the predatory rock cod Cephalophalis cyanostigma, anemonefish Amphiprion akindynos occupying healthy unbleached host anemones Heteractis crispa respond by feeding less and spending more time within the anemone tentacles. When the host anemone was experimentally bleached, these visual risk responses were compromised: A. akindynos continued to feed and did not seek shelter. The impaired behavioural response may prove detrimental to anemonefish populations as abundance levels of fish on bleached anemones was reduced by 60% within 3 d, which may have been the result of increased predation. Our data illustrate how climate-induced habitat degradation can drive declines of reef fish by potentially altering outcomes of predator–prey interactions.

  • 365.
    Lönnstedt, Oona M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    McCormick, Mark
    James Cook University.
    Damsel in distress: captured damselfish prey emit chemical cues that attract secondary predators and improve escape chances2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1818, p. 20152038-Article in journal (Refereed)
    Abstract [en]

    In aquatic environments, many prey animals possess damage-released chemical alarm cues that elicit antipredator behaviours in responsive conand heterospecifics. Despite considerable study, the selective advantage of alarm cues remains unclear. In an attempt to investigate one of the more promising hypotheses concerning the evolution of alarm cues, we examined whether the cue functions in a fashion analogous to the distress vocalizations emitted by many terrestrial animals. Our results suggest that chemical alarm cues in damselfish (Pomacentridae) may have evolved to benefit the cue sender by attracting secondary predators who disrupt the predation event, allowing the prey a greater chance to escape. The coral reef piscivore, the dusky dottyback (Pseudochromis fuscus), chemically eavesdrops on predation events and uses chemical alarm cues from fish prey (lemon damselfish; Pomacentrus moluccensis) in an attempt to find and steal prey from primary predators. Field studies showed that Ps. fuscus aggregate at sites where prey alarm cue has been experimentally released. Furthermore, secondary predators attempted to steal captured prey of primary predators in laboratory trials and enhanced prey escape chances by 35–40%. These results are the first, to the best of our knowledge, to demonstrate a mechanism by which marine fish may benefit from the production and release of alarm cues, and highlight the complex and important role that semiochemicals play in marine predator–prey interactions.

  • 366.
    Magyar, Donat
    et al.
    Natl Publ Hlth Ctr, Dept Air Hyg & Aerobiol, Budapest, Hungary..
    Vass, Mate
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Li, De-Wei
    Connecticut Agr Expt Stn Valley Lab, 153 Cook Hill Rd, Windsor, CT 06095 USA..
    Dispersal Strategies of Microfungi2016In: Biology of Microfungi, Springer Publishing Company, 2016, p. 315-371Chapter in book (Refereed)
    Abstract [en]

    Successful and efficient dispersal of fungi is crucial to the survival of the fungi, balance of ecosystems, and stability of biodiversities. Dispersal strategies of microfungi and other fungi are reviewed in detail based on the literature published in the last four decades. It covers the latest development of research on the dispersal process: liberation, transporation, deposition, resuspension, and survival of fungal spores and other propagules from microscale to macroscale. The characters of dispersal strategies of fungi from different habitats are elucidated. The fungal habitats include litter, soil, plants, insects, other animals, aquatic and marine environments, etc. For each strategy, the associated mechanisms are discussed for their ecological significance. The significance of the new technology used in the recent studies on dispersal strategies is presented. At the same time, current and future applications of dispersal strategies of microfungi are discussed in the chapter.

  • 367.
    Magyar, Donat
    et al.
    Natl Publ Hlth Ctr, Dept Air Hyg & Aerobiol, Budapest, Hungary..
    Vass, Mate
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Univ Pannonia, Dept Limnol, Veszprem, Hungary.
    Oros, Gyula
    Hungarian Acad Sci, Ctr Agr Res, Plant Protect Inst, H-1022 Budapest, Hungary..
    Dendrotelmata (water-filled tree holes) as fungal hotspots - a long term study2017In: Cryptogamie Mycologie, ISSN 0181-1584, E-ISSN 1776-100X, Vol. 38, no 1, p. 55-66Article in journal (Refereed)
    Abstract [en]

    Water-filled tree holes (dendrotelmata) are mostly ephemeral micro-ecosystems characterized by high level of heterotrophic microbial activity sustained by allochthonous organic matter. In this paper, description of a five-year long observation of fungal consortia in a Norway maple tree-hole is presented. Overall, 139 fungal taxa were detected. Among them, Excipularia fusispora, Ellisembia leptospora, Rebentischia unicaudata, Tricladium castaneicola, Thielavia terricola and Alternaria spp. occurred most frequently. Our observations suggest that even an individual dendrotelma represents an exceptional microhabitat, forming a hot-spot for microfungi due to its role as a natural spore trap and its (temporarily) aquatic environment. Our results show that this aquatic micro-ecosystem supports highly diverse mycobiota with continuous temporal dynamics, with an important fraction of sporadic taxa.

  • 368. Mantzouki, Evanthia
    et al.
    Beklioǧlu, Meryem
    Brookes, Justin D.
    de Senerpont Domis, Lisette Nicole
    Dugan, Hilary A.
    Doubek, Jonathan P.
    Grossart, Hans-Peter
    Nejstgaard, Jens C.
    Pollard, Amina I.
    Ptacnik, Robert
    Rose, Kevin C.
    Sadro, Steven
    Seelen, Laura
    Skaff, Nicholas K.
    Teubner, Katrin
    Weyhenmeyer, Gesa A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Ibelings, Bastiaan W.
    Snapshot Surveys for Lake Monitoring, More Than a Shot in the Dark2018In: Frontiers in Ecology and Evolution, E-ISSN 2296-701X, Vol. 6, article id 201Article in journal (Refereed)
  • 369. Mantzouki, Evanthia
    et al.
    Bravo, Andrea Garcia
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Urrutia Cordero, Pablo
    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.
    Colom-Montero, William
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Pierson, Don
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    A European Multi Lake Survey dataset of environmental variables , phytoplankton pigments and cyanotoxins2018In: Scientific Data, E-ISSN 2052-4463, Vol. 5, no October, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.

  • 370.
    Mantzouki, Evanthia
    et al.
    Univ Geneva, Dept FA Forel Environm & Aquat Sci, CH-1205 Geneva, Switzerland.
    Lurling, Miquel
    Wageningen Univ & Res, Dept Environm Sci, NL-6700 Wageningen, Netherlands;Netherlands Inst Ecol NIOO KNAW, Dept Aquat Ecol, NL-6700 Wageningen, Netherlands.
    Fastner, Jutta
    German Environm Agcy, Unit Drinking Water Resources & Water Treatment, Correnspl 1, D-14195 Berlin, Germany.
    Domis, Lisette de Senerpont
    Wageningen Univ & Res, Dept Environm Sci, NL-6700 Wageningen, Netherlands;Netherlands Inst Ecol NIOO KNAW, Dept Aquat Ecol, NL-6700 Wageningen, Netherlands.
    Wilk-Wozniak, Elzbieta
    Polish Acad Sci, Inst Nat Conservat, PL-31120 Krakow, Poland.
    Koreiviene, Judita
    Nat Res Ctr, Inst Bot, LT-08412 Vilnius, Lithuania.
    Seelen, Laura
    Wageningen Univ & Res, Dept Environm Sci, NL-6700 Wageningen, Netherlands;Netherlands Inst Ecol NIOO KNAW, Dept Aquat Ecol, NL-6700 Wageningen, Netherlands.
    Teurlincx, Sven
    Netherlands Inst Ecol NIOO KNAW, Dept Aquat Ecol, NL-6700 Wageningen, Netherlands.
    Verstijnen, Yvon
    Wageningen Univ & Res, Dept Environm Sci, NL-6700 Wageningen, Netherlands.
    Krzton, Wojciech
    Polish Acad Sci, Inst Nat Conservat, PL-31120 Krakow, Poland.
    Walusiak, Edward
    Polish Acad Sci, Inst Nat Conservat, PL-31120 Krakow, Poland.
    Karosiene, Jurate
    Nat Res Ctr, Inst Bot, LT-08412 Vilnius, Lithuania.
    Kasperoviciene, Jurate
    Nat Res Ctr, Inst Bot, LT-08412 Vilnius, Lithuania.
    Savadova, Ksenija
    Nat Res Ctr, Inst Bot, LT-08412 Vilnius, Lithuania.
    Vitonyte, Irma
    Nat Res Ctr, Inst Bot, LT-08412 Vilnius, Lithuania.
    Cillero-Castro, Carmen
    3Edata, R&D Dept Environm Engn, Lugo 27004, Spain.
    Budzynska, Agnieszka
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Goldyn, Ryszard
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Kozak, Anna
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Rosinska, Joanna
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Szelag-Wasielewska, Elzbieta
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Domek, Piotr
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Jakubowska-Krepska, Natalia
    Adam Mickiewicz Univ, Dept Water Protect, PL-61614 Poznan, Poland.
    Kwasizur, Kinga
    Adam Mickiewicz Univ, Dept Hydrobiol, PL-61614 Poznan, Poland.
    Messyasz, Beata
    Adam Mickiewicz Univ, Dept Hydrobiol, PL-61614 Poznan, Poland.
    Pelechata, Aleksandra
    Adam Mickiewicz Univ, Dept Hydrobiol, PL-61614 Poznan, Poland.
    Pelechaty, Mariusz
    Adam Mickiewicz Univ, Dept Hydrobiol, PL-61614 Poznan, Poland.
    Kokocinski, Mikolaj
    Adam Mickiewicz Univ, Dept Hydrobiol, PL-61614 Poznan, Poland.
    Garcia-Murcia, Ana
    AECOM URS, Dept Limnol & Water Qual, Barcelona 08036, Spain.
    Real, Monserrat
    AECOM URS, Dept Limnol & Water Qual, Barcelona 08036, Spain.
    Romans, Elvira
    AECOM URS, Dept Limnol & Water Qual, Barcelona 08036, Spain.
    Noguero-Ribes, Jordi
    AECOM URS, Dept Limnol & Water Qual, Barcelona 08036, Spain.
    Parreno Duque, David
    AECOM URS, Dept Limnol & Water Qual, Barcelona 08036, Spain.
    Fernandez-Moran, Elisabeth
    AECOM URS, Dept Limnol & Water Qual, Barcelona 08036, Spain.
    Karakaya, Nusret
    Abant Izzet Baysal Univ, Dept Environm Engn, TR-14280 Bolu, Turkey.
    Haggqvist, Kerstin
    Abo Akad Univ, Dept Sci & Engn, FIN-20520 Turku, Finland.
    Demir, Nilsun
    Ankara Univ, Dept Fisheries & Aquaculture, TR-6100 Ankara, Turkey.
    Beklioglu, Meryem
    Middle East Tech Univ, Dept Biol, TR-6800 Ankara, Turkey.
    Filiz, Nur
    Middle East Tech Univ, Dept Biol, TR-6800 Ankara, Turkey.
    Levi, Eti E.
    Middle East Tech Univ, Dept Biol, TR-6800 Ankara, Turkey.
    Iskin, Ugur
    Middle East Tech Univ, Dept Biol, TR-6800 Ankara, Turkey.
    Bezirci, Gizem
    Middle East Tech Univ, Dept Biol, TR-6800 Ankara, Turkey.
    Tavsanoglu, Ulku Nihan
    Middle East Tech Univ, Dept Biol, TR-6800 Ankara, Turkey.
    Ozhan, Koray
    Middle East Tech Univ, Dept Oceanog, Inst Marine Sci, TR-06800 Ankara, Turkey.
    Gkelis, Spyros
    Aristotle Univ Thessaloniki, Dept Bot, Thessaloniki 54124, Greece.
    Panou, Manthos
    Aristotle Univ Thessaloniki, Dept Bot, Thessaloniki 54124, Greece.
    Fakioglu, Ozden
    Ataturk Univ, Dept Basic Sci, TR-25240 Erzurum, Turkey.
    Avagianos, Christos
    Athens Water Supply & Sewerage Co, Water Qual Dept, Athens 11146, Greece.
    Kaloudis, Triantafyllos
    Athens Water Supply & Sewerage Co, Water Qual Dept, Athens 11146, Greece.
    Celik, Kemal
    Balikesir Univ, Dept Biol, TR-10145 Balikesir, Turkey.
    Yilmaz, Mete
    Bursa Tech Univ, Dept Bioengn, TR-16310 Bursa, Turkey.
    Marce, Rafael
    Catalan Inst Water Res ICRA, Girona 17003, Spain.
    Catalán, Núria
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Catalan Inst Water Res ICRA, Girona 17003, Spain.
    Bravo, Andrea Garcia
    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.
    Colom-Montero, William
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Mustonen, Kristiina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Pierson, Don
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Yang, Yang
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Raposeiro, Pedro M.
    Univ Azores, Fac Sci & Technol, InBIO Associated Lab, Res Ctr Biodivers & Genet Resources CIBIO Azores, P-9501801 Ponta Delgada, Portugal.
    Goncalves, Vitor
    Univ Azores, Fac Sci & Technol, InBIO Associated Lab, Res Ctr Biodivers & Genet Resources CIBIO Azores, P-9501801 Ponta Delgada, Portugal.
    Antoniou, Maria G.
    Cyprus Univ Technol, Dept Environm Sci & Technol, CY-3036 Lemesos, Cyprus.
    Tsiarta, Nikoletta
    Cyprus Univ Technol, Dept Environm Sci & Technol, CY-3036 Lemesos, Cyprus.
    McCarthy, Valerie
    Dundalk Inst Technol, Ctr Freshwater & Environm Studies, Dundalk A91 K584, Ireland.
    Perello, Victor C.
    Dundalk Inst Technol, Ctr Freshwater & Environm Studies, Dundalk A91 K584, Ireland.
    Feldmann, Tonu
    Estonian Univ Life Sci, Inst Agr & Environm Sci, EE-51014 Tartu, Estonia.
    Laas, Alo
    Estonian Univ Life Sci, Inst Agr & Environm Sci, EE-51014 Tartu, Estonia.
    Panksep, Kristel
    Estonian Univ Life Sci, Inst Agr & Environm Sci, EE-51014 Tartu, Estonia.
    Tuvikene, Lea
    Estonian Univ Life Sci, Inst Agr & Environm Sci, EE-51014 Tartu, Estonia.
    Gagala, Ilona
    Polish Acad Sci, European Reg Ctr Ecohydrol, PL-90364 Lodz, Poland.
    Mankiewicz-Boczek, Joana
    Polish Acad Sci, European Reg Ctr Ecohydrol, PL-90364 Lodz, Poland.
    Yagci, Meral Apaydin
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Cinar, Sakir
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Capkin, Kadir
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Yagci, Abdulkadir
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Cesur, Mehmet
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Bilgin, Fuat
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Bulut, Cafer
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Uysal, Rahmi
    Republ Turkey Minist Food Agr, Fisheries Res Inst, TR-32500 Isparta, Turkey.
    Obertegger, Ulrike
    Fdn Edmund Mach, Dept Sustainable Ecosyst & Bioresources, I-38010 San Michele All Adige, Italy.
    Boscaini, Adriano
    Fdn Edmund Mach, Dept Sustainable Ecosyst & Bioresources, I-38010 San Michele All Adige, Italy.
    Flaim, Giovanna
    Fdn Edmund Mach, Dept Sustainable Ecosyst & Bioresources, I-38010 San Michele All Adige, Italy.
    Salmaso, Nico
    Fdn Edmund Mach, Dept Sustainable Ecosyst & Bioresources, I-38010 San Michele All Adige, Italy.
    Cerasino, Leonardo
    Fdn Edmund Mach, Dept Sustainable Ecosyst & Bioresources, I-38010 San Michele All Adige, Italy.
    Richardson, Jessica
    Univ Stirling, Dept Biol & Environm Sci, Stirling FK9 4LA, Scotland.
    Visser, Petra M.
    Univ Amsterdam, Dept Freshwater & Marine Ecol, NL-1090 GE Amsterdam, Netherlands.
    Verspagen, Jolanda M. H.
    Univ Amsterdam, Dept Freshwater & Marine Ecol, NL-1090 GE Amsterdam, Netherlands.
    Karan, Tunay
    Gaziosmanpasa Univ, Dept Mol Biol & Genet, TR-60250 Merkez, Turkey.
    Soylu, Elif Neyran
    Giresun Univ, Dept Biol, TR-28100 Giresun, Turkey.
    Maraslioglu, Faruk
    Hitit Univ, Dept Biol, TR-19040 Corum, Turkey.
    Napiorkowska-Krzebietke, Agnieszka
    Inland Fisheries Inst, Dept Icthyol Hydrobiol & Aquat Ecol, PL-10719 Olsztyn, Poland.
    Ochocka, Agnieszka
    Natl Res Inst, Dept Freshwater Protect, Inst Environm Protect, PL-01692 Warsaw, Poland.
    Pasztaleniec, Agnieszka
    Natl Res Inst, Dept Freshwater Protect, Inst Environm Protect, PL-01692 Warsaw, Poland.
    Antao-Geraldes, Ana M.
    Inst Politecn Braganca, Ctr Invest Montanha, Campus Santa Apolonia, P-5300253 Braganca, Portugal.
    Vasconcelos, Vitor
    Interdisciplinary Ctr Marine & Environm Res CIIMA, P-4450208 Matosinhos, Portugal;Univ Porto, P-4450208 Matosinhos, Portugal.
    Morais, Joao
    Interdisciplinary Ctr Marine & Environm Res CIIMA, P-4450208 Matosinhos, Portugal;Univ Porto, P-4450208 Matosinhos, Portugal.
    Vale, Micaela
    Interdisciplinary Ctr Marine & Environm Res CIIMA, P-4450208 Matosinhos, Portugal;Univ Porto, P-4450208 Matosinhos, Portugal.
    Koker, Latife
    Istanbul Univ, Fac Aquat Sci, Dept Freshwater Resource & Management, TR-34134 Istanbul, Turkey.
    Akcaalan, Reyhan
    Istanbul Univ, Fac Aquat Sci, Dept Freshwater Resource & Management, TR-34134 Istanbul, Turkey.
    Albay, Meric
    Istanbul Univ, Fac Aquat Sci, Dept Freshwater Resource & Management, TR-34134 Istanbul, Turkey.
    Maronic, Dubravka Spoljaric
    Josip Juraj Strossmayer Univ Osijek, Dept Biol, Osijek 31000, Croatia.
    Stevic, Filip
    Josip Juraj Strossmayer Univ Osijek, Dept Biol, Osijek 31000, Croatia.
    Pfeiffer, Tanja Zuna
    Josip Juraj Strossmayer Univ Osijek, Dept Biol, Osijek 31000, Croatia.
    Fonvielle, Jeremy
    Leibniz Inst Freshwater Ecol & Inland Fisheries, Dept Expt Limnol, D-16775 Stechlin, Germany.
    Straile, Dietmar
    Univ Konstanz, Limnol Inst, Dept Biol, D-78464 Constance, Germany.
    Rothhaupt, Karl-Otto
    Univ Konstanz, Limnol Inst, Dept Biol, D-78464 Constance, Germany.
    Hansson, Lars-Anders
    Lund Univ, Dept Biol, S-22362 Lund, Sweden.
    Urrutia Cordero, Pablo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Lund Univ, Dept Biol, S-22362 Lund, Sweden.
    Blaha, Ludek
    Masaryk Univ, RECETOX, Fac Sci, Brno 62500, Czech Republic.
    Geris, Rodan
    Morava Board Author, Dept Hydrobiol, Brno 60200, Czech Republic.
    Frankova, Marketa
    Czech Acad Sci, Inst Bot, Lab Paleoecol, Brno 60200, Czech Republic.
    Kocer, Mehmet Ali Turan
    Mediterranean Fisheries Res Prod & Training Inst, Dept Environm & Resource Management, TR-7090 Antalya, Turkey.
    Alp, Mehmet Tahir
    Mersin Univ, Fac Aquaculture, TR-33160 Mersin, Turkey.
    Remec-Rekar, Spela
    Slovenian Environm Agcy, Water Qual Dept, Ljubljana 1000, Slovenia.
    Elersek, Tina
    Natl Inst Biol, Dept Genet Toxicol & Canc Biol, Ljubljana 1000, Slovenia.
    Triantis, Theodoros
    Natl Ctr Sci Res Demokritos, Inst Nanosci & Nanotechnol, Attiki 15341, Greece.
    Zervou, Sevasti-Kiriaki
    Natl Ctr Sci Res Demokritos, Inst Nanosci & Nanotechnol, Attiki 15341, Greece.
    Hiskia, Anastasia
    Natl Ctr Sci Res Demokritos, Inst Nanosci & Nanotechnol, Attiki 15341, Greece.
    Haande, Sigrid
    Norwegian Inst Water Res, Dept Freshwater Ecol, N-0349 Oslo, Norway.
    Skjelbred, Birger
    Norwegian Inst Water Res, Dept Freshwater Ecol, N-0349 Oslo, Norway.
    Madrecka, Beata
    Poznan Univ Tech, Inst Environm Engn, PL-60965 Poznan, Poland.
    Nemova, Hana
    Publ Hlth Author Slovak Republ, Natl Reference Ctr Hydrobiol, Bratislava 82645, Slovakia.
    Drastichova, Iveta
    Publ Hlth Author Slovak Republ, Natl Reference Ctr Hydrobiol, Bratislava 82645, Slovakia.
    Chomova, Lucia
    Publ Hlth Author Slovak Republ, Natl Reference Ctr Hydrobiol, Bratislava 82645, Slovakia.
    Edwards, Christine
    Robert Gordon Univ, Sch Pharm & Life Sci, Aberdeen AB10 7GJ, Scotland.
    Sevindik, Tugba Ongun
    Sakarya Univ, Dept Biol, TR-54187 Sakarya, Turkey.
    Tunca, Hatice
    Sakarya Univ, Dept Biol, TR-54187 Sakarya, Turkey.
    OEnem, Burcin
    Sakarya Univ, Dept Biol, TR-54187 Sakarya, Turkey.
    Aleksovski, Boris
    SS Cyril & Methodius Univ, Fac Nat Sci & Math, Skopje 1000, Macedonia.
    Krstic, Svetislav
    SS Cyril & Methodius Univ, Fac Nat Sci & Math, Skopje 1000, Macedonia.
    Vucelic, Itana Bokan
    Teaching Inst Publ Hlth Primorje Gorski Kotar Cty, Dept Ecotoxicol, Rijeka 51000, Croatia.
    Nawrocka, Lidia
    State Univ Appl Sci, Inst Technol, PL-82300 Elblag, Poland.
    Salmi, Pauliina
    Univ Jyvaskyla, Dept Biol & Environm Sci, Jyvaskyla 40014, Finland.
    Machado-Vieira, Danielle
    Univ Fed Paraiba, Dept Sistemat & Ecol, BR-58059970 Joao Pessoa, Paraiba, Brazil.
    de Oliveira, Alinne Gurjao
    Univ Fed Paraiba, Dept Sistemat & Ecol, BR-58059970 Joao Pessoa, Paraiba, Brazil.
    Delgado-Martin, Jordi
    Univ A Coruna, Dept Civil Engn, La Coruna 15192, Spain.
    Garcia, David
    Univ A Coruna, Dept Civil Engn, La Coruna 15192, Spain.
    Cereijo, Jose Luis
    Univ A Coruna, Dept Civil Engn, La Coruna 15192, Spain.
    Goma, Joan
    Univ Barcelona, Dept Evolutionary Biol Ecol & Environm Sci, E-08028 Barcelona, Spain.
    Trapote, Mari Carmen
    Univ Barcelona, Dept Evolutionary Biol Ecol & Environm Sci, E-08028 Barcelona, Spain.
    Vegas-Vilarrubia, Teresa
    Univ Barcelona, Dept Evolutionary Biol Ecol & Environm Sci, E-08028 Barcelona, Spain.
    Obrador, Biel
    Univ Barcelona, Dept Evolutionary Biol Ecol & Environm Sci, E-08028 Barcelona, Spain.
    Grabowska, Magdalena
    Univ Bialystok, Dept Hydrobiol, PL-15245 Bialystok, Poland.
    Karpowicz, Maciej
    Univ Bialystok, Dept Hydrobiol, PL-15245 Bialystok, Poland.
    Chmura, Damian
    Univ Bielsko Biala, Inst Environm Protect & Engn, PL-43309 Bielsko Biala, Poland.
    Ubeda, Barbara
    Univ Cadiz, Dept Biol, Puerto Real 11510, Spain.
    Angel Galvez, Jose
    Univ Cadiz, Dept Biol, Puerto Real 11510, Spain.
    Ozen, Arda
    Univ Cankiri Karatekin, Dept Forest Engn, TR-18200 Cankiri, Turkey.
    Christoffersen, Kirsten Seestern
    Univ Copenhagen, Dept Biol, Freshwater Biol Lab, DK-2100 Copenhagen, Denmark.
    Warming, Trine Perlt
    Univ Copenhagen, Dept Biol, Freshwater Biol Lab, DK-2100 Copenhagen, Denmark.
    Kobos, Justyna
    Univ Gdansk, Dept Marine Biotechnol, PL-81378 Gdynia, Poland.
    Mazur-Marzec, Hanna
    Univ Gdansk, Dept Marine Biotechnol, PL-81378 Gdynia, Poland.
    Perez-Martinez, Carmen
    Univ Granada, Dept Ecol, E-18071 Granada, Spain.
    Ramos-Rodriguez, Eloisa
    Univ Granada, Dept Ecol, E-18071 Granada, Spain.
    Arvola, Lauri
    Univ Helsinki, Lammi Biol Stn, Lammi 16900, Finland.
    Alcaraz-Parraga, Pablo
    Univ Jaen, Dept Anim Biol Plant Biol & Ecol, Jaen 23701, Spain.
    Toporowska, Magdalena
    Univ Life Sci Lublin, Dept Hydrobiol & Protect Ecosyst, PL-20262 Lublin, Poland.
    Pawlik-Skowronska, Barbara
    Univ Life Sci Lublin, Dept Hydrobiol & Protect Ecosyst, PL-20262 Lublin, Poland.
    Niedzwiecki, Michal
    Univ Life Sci Lublin, Dept Hydrobiol & Protect Ecosyst, PL-20262 Lublin, Poland.
    Peczula, Wojciech
    Univ Life Sci Lublin, Dept Hydrobiol & Protect Ecosyst, PL-20262 Lublin, Poland.
    Leira, Manel
    Univ Lisbon, Inst Dom Luiz, P-1749016 Lisbon, Portugal.
    Hernandez, Armand
    CSIC, ICTJA, Inst Earth Sci Jaume Almera, Barcelona 08028, Spain.
    Moreno-Ostos, Enrique
    Univ Malaga, Dept Ecol, E-29071 Malaga, Spain.
    Maria Blanco, Jose
    Univ Malaga, Dept Ecol, E-29071 Malaga, Spain.
    Rodriguez, Valeriano
    Univ Malaga, Dept Ecol, E-29071 Malaga, Spain.
    Juan Montes-Perez, Jorge
    Univ Malaga, Dept Ecol, E-29071 Malaga, Spain.
    Palomino, Roberto L.
    Univ Malaga, Dept Ecol, E-29071 Malaga, Spain.
    Rodriguez-Perez, Estela
    Univ Malaga, Dept Ecol, E-29071 Malaga, Spain.
    Carballeira, Rafael
    Univ A Coruna, Fac Ciencias, CICA, La Coruna 15071, Spain.
    Camacho, Antonio
    Univ Valencia, Cavanilles Inst Biodivers & Evolutionary Biol, Paterna Valencia 46980, Spain.
    Picazo, Antonio
    Univ Valencia, Cavanilles Inst Biodivers & Evolutionary Biol, Paterna Valencia 46980, Spain.
    Rochera, Carlos
    Univ Valencia, Cavanilles Inst Biodivers & Evolutionary Biol, Paterna Valencia 46980, Spain.
    Santamans, Anna C.
    Univ Valencia, Cavanilles Inst Biodivers & Evolutionary Biol, Paterna Valencia 46980, Spain.
    Ferriol, Carmen
    Univ Valencia, Cavanilles Inst Biodivers & Evolutionary Biol, Paterna Valencia 46980, Spain.
    Romo, Susana
    Univ Valencia, Dept Microbiol & Ecol, E-46100 Burjassot, Spain.
    Miguel Soria, Juan
    Univ Valencia, Dept Microbiol & Ecol, E-46100 Burjassot, Spain.
    Dunalska, Julita
    Univ Warmia & Mazury, Dept Water Protect Engn, PL-10720 Olsztyn, Poland.
    Sienska, Justyna
    Univ Warmia & Mazury, Dept Water Protect Engn, PL-10720 Olsztyn, Poland.
    Szymanski, Daniel
    Univ Warmia & Mazury, Dept Water Protect Engn, PL-10720 Olsztyn, Poland.
    Kruk, Marek
    Univ Warmia & Mazury, Dept Tourism Recreat & Ecol, PL-10720 Olsztyn, Poland.
    Kostrzewska-Szlakowska, Iwona
    Univ Warsaw, Fac Biol, PL-02096 Warsaw, Poland.
    Jasser, Iwona
    Univ Warsaw, Dept Plant Ecol & Environm Conservat, Fac Biol, PL-02089 Warsaw, Poland.
    Zutinic, Petar
    Univ Zagreb, Dept Biol, Fac Sci, Zagreb 10000, Croatia.
    Udovic, Marija Gligora
    Univ Zagreb, Dept Biol, Fac Sci, Zagreb 10000, Croatia.
    Plenkovic-Moraj, Andelka
    Univ Zagreb, Dept Biol, Fac Sci, Zagreb 10000, Croatia.
    Frak, Magdalena
    Warsaw Univ Life Sci SGGW, Fac Civil & Environm Engn, Dept Environm Improvement, PL-02787 Warsaw, Poland.
    Bankowska-Sobczak, Agnieszka
    Warsaw Univ Life Sci SGGW, Fac Civil & Environm Engn, Dept Hydraul Engn, PL-02787 Warsaw, Poland.
    Wasilewicz, Michal
    Warsaw Univ Life Sci SGGW, Fac Civil & Environm Engn, Dept Hydraul Engn, PL-02787 Warsaw, Poland.
    Ozkan, Korhan
    Middle East Tech Univ, Inst Marine Sci Marine Biol & Fisheries, TR-06800 Ankara, Turkey.
    Maliaka, Valentini
    Wageningen Univ & Res, Dept Environm Sci, NL-6700 Wageningen, Netherlands;Soc Protect Prespa, Agios Germanos 53077, Greece;Radboud Univ Nijmegen, Dept Aquat Ecol & Environm Biol, Inst Water & Wetland Res, NL-6525 AJ Nijmegen, Netherlands.
    Kangro, Kersti
    Estonian Univ Life Sci, Inst Agr & Environm Sci, EE-51014 Tartu, Estonia;Univ Tartu, Fac Sci & Technol, Tartu Observ, EE-61602 Tartu, Estonia.
    Grossart, Hans-Peter
    Leibniz Inst Freshwater Ecol & Inland Fisheries, Dept Expt Limnol, D-16775 Stechlin, Germany;Univ Potsdam, Inst Biochem & Biol, D-14469 Potsdam, Germany.
    Paerl, Hans W.
    Univ N Carolina, Inst Marine Sci, Chapel Hill, NC 28557 USA.
    Carey, Cayelan C.
    Virginia Tech, Dept Biol Sci, Blacksburg, VA 24061 USA.
    Ibelings, Bas W.
    Univ Geneva, Dept FA Forel Environm & Aquat Sci, CH-1205 Geneva, Switzerland.
    Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins2018In: Toxins, ISSN 2072-6651, E-ISSN 2072-6651, Vol. 10, no 4, article id 156Article in journal (Refereed)
    Abstract [en]

    Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

  • 371. Marcé, Rafael
    et al.
    George, Glen
    Buscarinu, Paola
    Deidda, Melania
    Dunalska, Julita
    de Eyto, Elvira
    Flaim, Giovanna
    Grossart, Hans-Peter
    Istvanovics, Vera
    Lenhardt, Mirjana
    Moreno-Ostos, Enrique
    Obrador, Biel
    Ostrovsky, Ilia
    Pierson, Don
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Potužák, Jan
    Poikane, Sandra
    Rinke, Karsten
    Rodríguez-Mozaz, Sara
    Staehr, Peter A.
    Šumberová, Kateřina
    Waajen, Guido
    Weyhenmeyer, Gesa A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Weathers, Kathleen C.
    Zion, Mark
    Ibelings, Bas W.
    Jennings, Eleanor
    Automatic High Frequency Monitoring for Improved Lake and Reservoir Management2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 20, p. 10780-10794Article, review/survey (Refereed)
    Abstract [en]

    Recent technological developments have increased the number of variables being monitored in lakes and reservoirs using automatic high frequency monitoring (AHFM). However, design of AHFM systems and posterior data handling and interpretation are currently being developed on a site-by-site and issue-by-issue basis with minimal standardization of protocols or knowledge sharing. As a result, many deployments become short-lived or underutilized, and many new scientific developments that are potentially useful for water management and environmental legislation remain underexplored. This Critical Review bridges scientific uses of AHFM with their applications by providing an overview of the current AHFM capabilities, together with examples of successful applications. We review the use of AHFM for maximizing the provision of ecosystem services supplied by lakes and reservoirs (consumptive and non consumptive uses, food production, and recreation), and for reporting lake status in the EU Water Framework Directive. We also highlight critical issues to enhance the application of AHFM, and suggest the establishment of appropriate networks to facilitate knowledge sharing and technological transfer between potential users. Finally, we give advice on how modern sensor technology can successfully be applied on a larger scale to the management of lakes and reservoirs and maximize the ecosystem services they provide.

  • 372.
    Marklund, Maria H. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. School of Biological Sciences and The Environment Institute, University of Adelaide, North Terrace, SA 5005, Australia.
    The influence of trophic polymorphisms on habitat coupling in aquatic food webs2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Trophic cascades, together with other indirect interactions are important aspects in shaping the composition and abundance of species in the food web. Theoretically, movement of energy between systems, and coupling between habitats by mobile predators have been suggested as being important for food web stability and evenness. Individual diet specialisations have been shown to be widespread in many animal taxa. Although not widely studied, some studies have indicated that mobile predators that display individual specialisations, may have a reduced ability to couple habitats.

    In this thesis, by using field studies and an experimental study, my aim was to assess the individual specialisation displayed by Eurasian perch (Perca fluviatilis) and its influence on the ability of the perch to couple habitats. In the experiment, we also investigated the effect of habitat coupling, or the lack of habitat coupling, on the dynamics and stability of the resources in the ecosystem.

    We show that habitat diversity and resource availability influenced perch individual specialisation and morphological variation. We found that the perch total niche width decreased with decreasing habitat switching ability. We demonstrate asymmetrical habitat coupling ability in perch across pelagic and littoral habitats, providing evidence that not all individuals within a species respond in the same way when it comes to spatial coupling and thereby providing stability within a food web.

    Our results expand on previous work and suggest that habitat coupling ability can influence individual specialisations and niche width. Furthermore, we show the importance of individual specialisations in relation to habitat coupling. Finally, we provide evidence for the theory that a food web dominated by a food specialist should exhibit more variable resource dynamics than a food web dominated by a generalist predator by showing a greater indirect effect of predation on the phytoplankton levels when no habitat coupling occurs. While many models and theoretical concepts have proposed a stabilising effect of cross movement of energy and mobile predators, little empirical evidence exists that confirms this mechanism.

    In conclusion, my thesis gives some support for the theoretical predictions that habitats coupled by a generalist predator should be more stable.

    List of papers
    1. The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator
    Open this publication in new window or tab >>The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator
    Show others...
    2018 (English)In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 127, no 1, p. 160-169Article in journal (Refereed) Published
    Abstract [en]

    Individual diet and habitat specialisation are widespread in animal taxa and often related to levels of predation and competition. Mobile consumers such as predatory fish can stabilise lake food webs by ranging over a larger area than their prey, thereby switching between habitats. Although, this switching assumes that the predator has equal preference for the available prey, individual diet specialisation and morphological adaptations to different habitats could potentially prevent individuals from switching between habitats. In this study, we assessed the niche width and individual specialisation in Eurasian perch Perca fluviatilis in response to a shift in habitat use by manipulating the ability for this top predator to couple habitats. We ran an eight weeks pond experiment, to test the effect of habitat switching on diet and morphological specialisations. We show that habitat coupling influenced individual diet specialisation and niche use in expected directions where specialisation increased with decreasing habitat switching. In contrast to expectations, the morphological variation decreased with increasing diet specialisation. Our results expand on previous work and suggest that individual specialisation and niche width can impact the ability of mobile predators to couple habitats. Furthermore, it shows the importance of individual specialisations in relation to habitat coupling.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2018
    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-315718 (URN)10.1111/oik.04094 (DOI)000419102100015 ()
    Funder
    Swedish Research CouncilSwedish Research Council Formas
    Available from: 2017-02-20 Created: 2017-02-20 Last updated: 2018-12-11Bibliographically approved
    2. Habitat coupling mediates trophic cascades in an aquatic community
    Open this publication in new window or tab >>Habitat coupling mediates trophic cascades in an aquatic community
    2019 (English)In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 10, no 9Article in journal (Refereed) Published
    Abstract [en]

    Trophic cascades and other indirect effects can significantly mediate community interactions. Movement of energy between systems has been shown to be important for trophic cascades in food webs, where coupling between habitats can be important for food web stability and species evenness. To investigate the effects of habitat coupling on the stability and dynamics of chlorophyll a (used as a proxy for phytoplankton biomass), mediated by the abundance and composition of zooplankton and macroinvertebrates, we manipulated habitat use by the predator perch. We show a greater indirect effect of predation on phytoplankton abundance when no habitat coupling occurs, indicating a stronger predation effect and a decrease in zooplankton grazing pressure leading to an increase in phytoplankton biomass. Although we found a significant effect on chlorophyll a between the treatments, this effect was not evident in the abundance of prey resources of perch (zooplankton and macroinvertebrates). Other indirect effects, not measured in this study, such as compositional changes in prey groups, could potentially explain the lack of effect in prey resources. While there is a strong theoretical argument for the stabilizing effects of habitat coupling, empirical evidence is scarce. Our study offers tentative support for these theoretical predictions in a natural system.

    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-315717 (URN)10.1002/ecs2.2863 (DOI)000490766500019 ()
    Funder
    Swedish Research Council
    Available from: 2017-02-20 Created: 2017-02-20 Last updated: 2019-11-25Bibliographically approved
    3. Combining resource use assessment techniques reveals trade-offs in trophic specialization of polymorphic perch
    Open this publication in new window or tab >>Combining resource use assessment techniques reveals trade-offs in trophic specialization of polymorphic perch
    2016 (English)In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 7, no 8, article id e01387Article in journal (Refereed) Published
    Abstract [en]

    Trophic polymorphism has found to be common in many taxa and is a suggested mechanism of ecological speciation. To characterize the trophic linkages of specific morphotypes of organisms as well as a time-integrated niche use, several methods are available. In this study, we present data of multiple techniques to investigate the trophic divergence of Eurasian perch (Perca fluviatilis) that displays well-studied trophic polymorphism associated with littoral and pelagic habitats in lakes. We combined bulk stable isotope and fatty acid analyses on the muscle tissue of perch from three different lakes in Sweden with analyses of stomach content. By comparing the three methods, we aimed at providing a broad and highly resolved picture on the trophic divergence in freshwater fish. The degree in morphological divergence varied between perch caught in the three different lakes. Generally, perch caught in the pelagic zone were more streamlined compared to the ones caught in the littoral zone that had a deeper body, as shown by geometric morphometrics. The three diet assessment methods revealed different levels of information. Data on stomach content showed some preferences for specific dietary items in littoral and pelagic perch, but general trophic specialization could not be concluded due to the small sample size. Analyses of delta C-13 and delta N-15, however, confirmed these results as a long-term pattern connected to specific habitat use in two of the three lakes. Fatty acid signatures of perch reflected partly those of the prey items of the specific habitats. Although the proportions of the essential fatty acid 22:6n-3 were lower in littoral resources, the proportions in littoral fish were similar to the ones caught in the pelagic zone. We concluded that although a fundamental contribution from littoral resources exists in littoral phenotypes, a minor reliance on pelagic prey items is obviously needed to provide essential compounds. Thus, by combining the methods to characterize direct resource use (i.e., stomach analyses) with others that utilize trophic biomarkers (i.e., analyses of stable isotopes and fatty acids), we were able to illustrate the degree of variation in trophic divergence of perch but also shed some light on potential trade-offs that are related to resource specialization in freshwater fish.

    Keywords
    carbon stable isotopes; ecological speciation; fatty acid analysis; geometric morphometrics; Perca fluviatilis; resource polymorphism; Special Feature; Biomarkers in Trophic Ecology; stomach content analysis
    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-264657 (URN)10.1002/ecs2.1387 (DOI)000387208900001 ()
    Available from: 2015-10-15 Created: 2015-10-15 Last updated: 2017-12-01Bibliographically approved
    4. Asymmetrical habitat coupling of an aquatic predator: The importance of individual specialization
    Open this publication in new window or tab >>Asymmetrical habitat coupling of an aquatic predator: The importance of individual specialization
    Show others...
    2019 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 9, no 6, p. 3405-3415Article in journal (Refereed) Published
    Abstract [en]

    Predators should stabilize food webs because they can move between spatially separate habitats. However, predators adapted to forage on local resources may have a reduced ability to couple habitats. Here, we show clear asymmetry in the ability to couple habitats by Eurasian perch—a common polymorphic predator in European lakes. We sampled perch from two spatially separate habitats—pelagic and littoral zones—in Lake Erken, Sweden. Littoral perch showed stronger individual specialization, but they also used resources from the pelagic zone, indicating their ability to couple habitats. In contrast, pelagic perch showed weaker individual specialization but near complete reliance on pelagic resources, indicating their preference to one habitat. This asymmetry in the habitat coupling ability of perch challenges the expectation that, in general, predators should stabilize spatially separated food webs. Our results suggest that habitat coupling might be constrained by morphological adaptations, which in this case were not related to genetic differentiation but were more likely related to differences in individual specialization.

    Keywords
    diet specialization, food web, landscape genetics, morphological specialization, Perca fluviatilis
    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-315719 (URN)10.1002/ece3.4973 (DOI)000462384800024 ()30962901 (PubMedID)
    Funder
    Swedish Research Council
    Note

    Title in thesis list of papers: Asymmetrical habitat coupling of a top predator

    Available from: 2017-02-20 Created: 2017-02-20 Last updated: 2019-11-25Bibliographically approved
  • 373.
    Marklund, Maria H. K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. School of Biological Sciences and The Environment Institute, University of Adelaide, North Terrace, SA 5005, Australia.
    Svanbäck, Richard
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Eklöv, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Habitat coupling mediates trophic cascades in an aquatic community2019In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 10, no 9Article in journal (Refereed)
    Abstract [en]

    Trophic cascades and other indirect effects can significantly mediate community interactions. Movement of energy between systems has been shown to be important for trophic cascades in food webs, where coupling between habitats can be important for food web stability and species evenness. To investigate the effects of habitat coupling on the stability and dynamics of chlorophyll a (used as a proxy for phytoplankton biomass), mediated by the abundance and composition of zooplankton and macroinvertebrates, we manipulated habitat use by the predator perch. We show a greater indirect effect of predation on phytoplankton abundance when no habitat coupling occurs, indicating a stronger predation effect and a decrease in zooplankton grazing pressure leading to an increase in phytoplankton biomass. Although we found a significant effect on chlorophyll a between the treatments, this effect was not evident in the abundance of prey resources of perch (zooplankton and macroinvertebrates). Other indirect effects, not measured in this study, such as compositional changes in prey groups, could potentially explain the lack of effect in prey resources. While there is a strong theoretical argument for the stabilizing effects of habitat coupling, empirical evidence is scarce. Our study offers tentative support for these theoretical predictions in a natural system.

  • 374.
    Marklund, Maria H. K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. School of Biological Sciences and The Environment Institute, University of Adelaide, North Terrace, SA 5005, Australia.
    Svanbäck, Richard
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Faulks, Leanne
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Sugadaira Montane Research Center, University of Tsukuba, Sugadairakogen 1278-294, Ueda, Nagano 386-2204, Japan.
    Breed, Martin F.
    School of Biological Sciences and The Environment Institute, University of Adelaide, North Terrace, SA 5005, Australia.
    Scharnweber, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Zha, Yinghua
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, NKS BioClinicum, Solna, Sweden.
    Eklöv, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Asymmetrical habitat coupling of an aquatic predator: The importance of individual specialization2019In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 9, no 6, p. 3405-3415Article in journal (Refereed)
    Abstract [en]

    Predators should stabilize food webs because they can move between spatially separate habitats. However, predators adapted to forage on local resources may have a reduced ability to couple habitats. Here, we show clear asymmetry in the ability to couple habitats by Eurasian perch—a common polymorphic predator in European lakes. We sampled perch from two spatially separate habitats—pelagic and littoral zones—in Lake Erken, Sweden. Littoral perch showed stronger individual specialization, but they also used resources from the pelagic zone, indicating their ability to couple habitats. In contrast, pelagic perch showed weaker individual specialization but near complete reliance on pelagic resources, indicating their preference to one habitat. This asymmetry in the habitat coupling ability of perch challenges the expectation that, in general, predators should stabilize spatially separated food webs. Our results suggest that habitat coupling might be constrained by morphological adaptations, which in this case were not related to genetic differentiation but were more likely related to differences in individual specialization.

  • 375.
    Marklund, Maria H. K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Water Research Centre and The Environment Institute, School of Biological Sciences, Univ. of Adelaide, North Terrace, SA, Australia.
    Svanbäck, Richard
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Zha, Yinghua
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Scharnweber, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Eklöv, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator2018In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 127, no 1, p. 160-169Article in journal (Refereed)
    Abstract [en]

    Individual diet and habitat specialisation are widespread in animal taxa and often related to levels of predation and competition. Mobile consumers such as predatory fish can stabilise lake food webs by ranging over a larger area than their prey, thereby switching between habitats. Although, this switching assumes that the predator has equal preference for the available prey, individual diet specialisation and morphological adaptations to different habitats could potentially prevent individuals from switching between habitats. In this study, we assessed the niche width and individual specialisation in Eurasian perch Perca fluviatilis in response to a shift in habitat use by manipulating the ability for this top predator to couple habitats. We ran an eight weeks pond experiment, to test the effect of habitat switching on diet and morphological specialisations. We show that habitat coupling influenced individual diet specialisation and niche use in expected directions where specialisation increased with decreasing habitat switching. In contrast to expectations, the morphological variation decreased with increasing diet specialisation. Our results expand on previous work and suggest that individual specialisation and niche width can impact the ability of mobile predators to couple habitats. Furthermore, it shows the importance of individual specialisations in relation to habitat coupling.

  • 376. Marotta, H.
    et al.
    Duarte, C. M.
    Sobek, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Enrich-Prast, A.
    Large CO2 disequilibria in tropical lakes2009In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 23Article in journal (Refereed)
    Abstract [en]

    On the basis of a broad compilation of data on pCO(2) in surface waters, we show tropical lakes to be, on average, far more supersaturated and variable in CO2 (geometric mean +/- SE pCO(2) = 1804 +/- 35 mu atm) than temperate lakes (1070 +/- 6 mu atm). There was a significant negative relationship between pCO(2) and latitude, resulting in an average decrease of pCO(2) by 2.8 +/- 0.5% per degree latitude. In addition, we found a general positive relationship between pCO(2) and water temperature across lakes involving an average increase (+/-SE) in 6.7 +/- 0.8% per degrees C. A conservative annual efflux from global lakes to the atmosphere was reestimated to 0.44 Gt C. Our results show tropical lakes maintain large CO2 disequilibria with the atmosphere, playing a disproportionate and variable role in the flux of CO between lakes and the atmosphere, thereby being a significant component of the global C cycle.

  • 377. Marotta, H.
    et al.
    Pinho, L.
    Gudasz, Cristian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Bastviken, D.
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Enrich-Prast, A.
    Greenhouse gas production in low-latitude lake sediments responds strongly to warming2014In: Nature Climate Change, ISSN 1758-678X, E-ISSN 1758-6798, Vol. 4, no 6, p. 467-470Article in journal (Refereed)
    Abstract [en]

    Inland water sediments receive large quantities of terrestrial organic matter(1-5) and are globally important sites for organic carbon preservation(5,6). Sediment organic matter mineralization is positively related to temperature across a wide range of high-latitude ecosystems(6-10), but the situation in the tropics remains unclear. Here we assessed temperature effects on the biological production of CO2 and CH4 in anaerobic sediments of tropical lakes in the Amazon and boreal lakes in Sweden. On the basis of conservative regional warming projections until 2100 (ref. 11), we estimate that sediment CO2 and CH4 production will increase 9-61% above present rates. Combining the CO2 and CH4 as CO2 equivalents (CO(2)eq; ref. 11), the predicted increase is 2.4-4.5 times higher in tropical than boreal sediments. Although the estimated lake area in low latitudes is 3.2 times smaller than that of the boreal zone, we estimate that the increase in gas production from tropical lake sediments would be on average 2.4 times higher for CO2 and 2.8 times higher for CH4. The exponential temperature response of organic matter mineralization, coupled with higher increases in the proportion of CH4 relative to CO2 on warming, suggests that the production of greenhouse gases in tropical sediments will increase substantially. This represents a potential large-scale positive feedback to climate change.

  • 378.
    Martí, Magalí
    et al.
    Department of Thematic Studies – Environmental Change, Linköping University, SE-581 83 Linköping, Sweden.
    Juottonen, Heli
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Robroek, Bjorn J.M.
    Ecology and Biodiversity Group, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
    Yrjälä, Kim
    MEM-group, Department of Biosciences, University of Helsinki, FIN-00014 Helsinki, Finland.
    Danielsson, Åsa
    Department of Thematic Studies – Environmental Change, Linköping University, SE-581 83 Linköping, Sweden.
    Lindgren, Per-Eric
    Division of Medical Microbiology, Department of Clinical and Experimental Medicine, Linköping University, SE-581 85 Linköping, Sweden.
    Svensson, Bo H.
    Department of Thematic Studies – Environmental Change, Linköping University, SE-581 83 Linköping, Sweden.
    Nitrogen and methanogen community composition within and among three Sphagnum dominated peatlands in Scandinavia2015In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 81, p. 204-211Article in journal (Refereed)
    Abstract [en]

    Abstract Ombrotrophic raised bogs are nutrient poor acidic peatlands accumulating organic matter. They are widely spread on northern latitudes and are substantial sources of methane emissions to the atmosphere being of great concern from a climate change perspective. We investigated the methanogen community composition along microtopographic gradients within three bogs in Scandinavia, receiving different amounts of nitrogen precipitation. Methanogenic community analyses by terminal restriction fragment length polymorphism of the mcrA gene showed different profiles among the three sites, while no influence of the microtopographic gradients was observed. Peat temperature and dissolved organic carbon were the major edaphic variables explaining 38% of the variation of the methanogenic community diversity among the bogs. The family Methanoregulaceae (hydrogenotrophic methanogens) showed the largest relative proportion and highest activity in all three sites. Quantitative PCR of the mcrA gene and transcripts showed that the most northern site, receiving the lowest atmospheric nitrogen load, had significantly lower abundance and activity of methanogens (4.7 × 106 and 2.4 × 104 mcrA copies per gram of soil, respectively), compared to the most southern site (8.2 × 107 and 4.6 × 105 mcrA copies per gram of soil, respectively), receiving the highest nitrogen load. No patterns of the mcrA gene and transcript abundances were observed along the microtopography. The results indicated that the difference in occurrence of methanogens is mainly due to geoclimatological conditions rather than site intrinsic microtopographic variation. The study further suggests that environmental changes on the site intrinsic topography will not affect the methanogenic activity, while increasing average temperatures in Scandinavian ombrotrophic raised bogs might contribute to an increase of the methanogenic archaeal activity resulting in an increase of methane production.

  • 379. Masse, M.
    et al.
    Bourgeois, O.
    Le Mouelic, S.
    Verpoorter, Charles
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Spiga, A.
    Le Deit, L.
    Wide distribution and glacial origin of polar gypsum on Mars2012In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 317, p. 44-55Article in journal (Refereed)
    Abstract [en]

    The North Polar Cap of Mars is associated with different kinds of superficial sediments, including the Circumpolar Dune Field, interior dune fields and sedimentary veneers scattered over the ice cap. In order to resolve the mineralogical composition and the regional distribution of these sediments, we processed OMEGA and CRISM hyperspectral data with an original method based on spectral derivation. We find that gypsum is present in all areas where undefined hydrated minerals had been previously detected, including superficial sedimentary veneers covering the North Polar Cap, interior dune fields and the whole Circumpolar Dune Field. Morphological and structural analyses reveal that these gypsum crystals derive directly from the interior of the ice cap. The source of superficial sedimentary veneers is the dust that was previously contained in the upper part of the ice cap, the ice-rich North Polar Layered Deposits (NPLD). This gypsum-bearing dust was released, on south-facing slopes of spiral troughs and arcuate scarps, by ice ablation controlled by katabatic winds. By the analysis of all associations of erosional scarps and dune fields over the North Polar Cap, we also demonstrate that the polar dunes are composed of sand-sized particles that were previously contained in the sediment-rich Basal Unit (BU), corresponding to the lower part of the ice cap. These particles contain gypsum and were released from the BU, by regressive ablation of ice at marginal scarps that border the North Polar Cap and by vertical ablation of ice on Olympia Planum. From a reconstruction of wind streamlines over and around the ice cap, we infer that katabatic winds descending from the polar high and rotating around the North Polar Cap control the release of these gypsum-bearing particles by ice ablation and the redistribution of these particles in the Circumpolar Dune Field.

  • 380. Matthews, Blake
    et al.
    Narwani, Anita
    Hausch, Stephen
    Nonaka, Etsuko
    Peter, Hannes
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Yamamichi, Masato
    Sullam, Karen E.
    Bird, Kali C.
    Thomas, Mridul K.
    Hanley, Torrance C.
    Turner, Caroline B.
    Toward an integration of evolutionary biology and ecosystem science2011In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 14, no 7, p. 690-701Article, review/survey (Refereed)
    Abstract [en]

    At present, the disciplines of evolutionary biology and ecosystem science are weakly integrated. As a result, we have a poor understanding of how the ecological and evolutionary processes that create, maintain, and change biological diversity affect the flux of energy and materials in global biogeochemical cycles. The goal of this article was to review several research fields at the interfaces between ecosystem science, community ecology and evolutionary biology, and suggest new ways to integrate evolutionary biology and ecosystem science. In particular, we focus on how phenotypic evolution by natural selection can influence ecosystem functions by affecting processes at the environmental, population and community scale of ecosystem organization. We develop an eco-evolutionary model to illustrate linkages between evolutionary change (e. g. phenotypic evolution of producer), ecological interactions (e. g. consumer grazing) and ecosystem processes (e. g. nutrient cycling). We conclude by proposing experiments to test the ecosystem consequences of evolutionary changes.

  • 381.
    McCallister, S. L.
    et al.
    Virginia Commonwealth Univ, Dept Biol & Environm Sci, Richmond, VA USA.
    Ishikawa, N. F.
    Swiss Fed Inst Technol, Dept Earth Sci, Zurich, Switzerland.
    Kothawala, Dolly
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Biogeochemical tools for characterizing organic carbon in inland aquatic ecosystems2018In: Limnology and Oceanography Letters, E-ISSN 2378-2242, Vol. 3, p. 444-457Article in journal (Refereed)
    Abstract [en]

    Integration of inland waters into regional and global carbon (C) budgets requires a comprehensive understand- ing of factors regulating organic carbon (OC) delivery and in situ processing. This study reviews advances in optical, molecular, and isotopic approaches to resolve the sources, ages, and transformations of OC in aquatic systems. OC characterization using excitation emission matrix spectra, Fourier transform ion cyclotron mass spectrometry, and nuclear magnetic resonance provides detailed molecular level insight. Radiocarbon isotopic approaches and compound-specific techniques resolve the input, metabolic fate, and turnover time of OC in ecosystems ranging in size from streams to the open ocean. Accumulating evidence suggests that aquatic OC is composed of diverse biogeochemical components. We conclude with enduring and emerging questions that underscore the role of inland systems in the global C cycle and propose unique combinations of approaches to better discern their role in the delivery and transformation of OC from soils to seas.

  • 382.
    McCormick, Mark I.
    et al.
    James Cook Univ, ARC Ctr Excellence Coral Reef Studies, Townsville, Qld 4811, Australia.;James Cook Univ, Coll Marine & Environm Sci, Townsville, Qld 4811, Australia..
    Lönnstedt, Oona M.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. James Cook Univ, ARC Ctr Excellence Coral Reef Studies, Townsville, Qld 4811, Australia.;James Cook Univ, Coll Marine & Environm Sci, Townsville, Qld 4811, Australia..
    Disrupted learning: habitat degradation impairs crucial antipredator responses in naive prey2016In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 283, no 1830, article id 20160441Article in journal (Refereed)
    Abstract [en]

    Habitat degradation is a global problem and one of the main causes of bio-diversity loss. Though widespread, the mechanisms that underlie faunal changes are poorly understood. In tropical marine systems, corals play a crucial role in forming habitat, but coral cover on many reefs is declining sharply. Coral degradation affects the olfactory cues that provide reliable information on the presence and intensity of threat. Here, we show for the first time that the ability of a habitat generalist to learn predators using an efficient and widespread method of predator learning is compromised in degraded coral habitats. Results indicate that chemical alarm cues are no longer indicative of a local threat for the habitat generalist (the damselfish, Pomacentrus amboinensis), and these cues can no longer be used to learn the identity of novel predators in degraded habitats. By contrast, a rubble specialist and congeneric (Pomacentrus coelestis) responded to olfactory threat cues regardless of background environment and could learn the identity of a novel predator using chemical alarm cues. Understanding how some species can cope with or acclimate to the detrimental impacts of habitat degradation on risk assessment abilities will be crucial to defining the scope of resilience in threatened communities.

  • 383. Mehner, Thomas
    et al.
    Attermeyer, Katrin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Brauns, Mario
    Brothers, Soren
    Diekmann, Jochen
    Gaedke, Ursula
    Grossart, Hans-Peter
    Köhler, Jan
    Lischke, Betty
    Meyer, Nils
    Scharnweber, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Syväranta, Jari
    Vanni, Michael J.
    Hilt, Sabine
    Weak response of animal allochthony and production to enhanced supply of terrestrial leaf litter in nutrient-rich lakes2016In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 19, no 2, p. 311-325Article in journal (Refereed)
    Abstract [en]

    Ecosystems are generally linked via fluxes of nutrients and energy across their boundaries. For example, freshwater ecosystems in temperate regions may receive significant inputs of terrestrially derived carbon via autumnal leaf litter. This terrestrial particulate organic carbon (POC) is hypothesized to subsidize animal production in lakes, but direct evidence is still lacking. We divided two small eutrophic lakes each into two sections and added isotopically distinct maize litter to the treatment sections to simulate increased terrestrial POC inputs via leaf litter in autumn. We quantified the reliance of aquatic consumers on terrestrial resources (allochthony) in the year subsequent to POC additions by applying mixing models of stable isotopes. We also estimated lake-wide carbon (C) balances to calculate the C flow to the production of the major aquatic consumer groups: benthic macroinvertebrates, crustacean zooplankton, and fish. The sum of secondary production of crustaceans and benthic macroinvertebrates supported by terrestrial POC was higher in the treatment sections of both lakes. In contrast, total secondary and tertiary production (supported by both autochthonous and allochthonous C) was higher in the reference than in the treatment sections of both lakes. Average aquatic consumer allochthony per lake section was 27–40%, although terrestrial POC contributed less than about 10% to total organic C supply to the lakes. The production of aquatic consumers incorporated less than 5% of the total organic C supply in both lakes, indicating a low ecological efficiency. We suggest that the consumption of terrestrial POC by aquatic consumers facilitates a strong coupling with the terrestrial environment. However, the high autochthonous production and the large pool of autochthonous detritus in these nutrient-rich lakes make terrestrial POC quantitatively unimportant for the C flows within food webs.

  • 384.
    Mehner, Thomas
    et al.
    Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
    Lischke, Betty
    Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
    Scharnweber, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
    Attermeyer, Katrin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
    Brothers, Soren
    Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany;Department of Watershed Sciences and Ecology Center, Utah State University, Logan, Utah, USA.
    Gaedke, Ursula
    Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
    Hilt, Sabine
    Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
    Brucet, Sandra
    Aquatic Ecology Group, University of Vic – Central University of Catalonia, Vic, Barcelona, Catalonia, Spain;Catalan Institution for Research and Advanced Studies ICREA, Barcelona, Catalonia, Spain.
    Empirical correspondence between trophic transfer efficiency in freshwater food webs and the slope of their size spectra2018In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 99, no 6, p. 1463-1472Article in journal (Refereed)
    Abstract [en]

    The density of organisms declines with size, because larger organisms need more energy than smaller ones and energetic losses occur when larger organisms feed on smaller ones. A potential expression of density-size distributions are Normalized Biomass Size Spectra (NBSS), which plot the logarithm of biomass independent of taxonomy within bins of logarithmic organismal size, divided by the bin width. Theoretically, the NBSS slope of multi-trophic communities is exactly - 1.0 if the trophic transfer efficiency (TTE, ratio of production rates between adjacent trophic levels) is 10% and the predator-prey mass ratio (PPMR) is fixed at 10(4). Here we provide evidence from four multi-trophic lake food webs that empirically estimated TTEs correspond to empirically estimated slopes of the respective community NBSS. Each of the NBSS considered pelagic and benthic organisms spanning size ranges from bacteria to fish, all sampled over three seasons in 1 yr. The four NBSS slopes were significantly steeper than -1.0 (range -1.14 to -1.19, with 95% CIs excluding -1). The corresponding average TTEs were substantially lower than 10% in each of the four food webs (range 1.0% to 3.6%, mean 1.85%). The overall slope merging all biomass-size data pairs from the four systems (-1.17) was almost identical to the slope predicted from the arithmetic mean TTE of the four food webs (-1.18) assuming a constant PPMR of 10(4). Accordingly, our empirical data confirm the theoretically predicted quantitative relationship between TTE and the slope of the biomass-size distribution. Furthermore, we show that benthic and pelagic organisms can be merged into a community NBSS, but future studies have yet to explore potential differences in habitat-specific TTEs and PPMRs. We suggest that community NBSS may provide valuable information on the structure of food webs and their energetic pathways, and can result in improved accuracy of TTE-estimates.

  • 385. Mendonca, Raquel
    et al.
    Kosten, Sarian
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Barros, Nathan
    Cole, Jonathan J.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Roland, Fabio
    Hydroelectric carbon sequestration2012In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 5, no 12, p. 838-840Article in journal (Refereed)
  • 386.
    Mendonca, Raquel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Kosten, Sarian
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Barros, Nathan
    J Cole, Jonathan
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Roland, Fábio
    Hydroelectric carbon sequestration2012In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 5, p. 838-840Article in journal (Refereed)
  • 387.
    Mendonca, Raquel
    et al.
    Univ Fed Juiz de Fora, Aquat Ecol Lab, BR-36036900 Juiz De Fora, MG, Brazil; Wageningen Univ, Dept Aquat Ecol & Water Qual Management, NL-6700 AP Wageningen, Netherlands.
    Kosten, Sarian
    Wageningen Univ, Dept Aquat Ecol & Water Qual Management, NL-6700 AP Wageningen, Netherlands; Leibniz Inst Freshwater Ecol & Inland Fisheries I, Berlin, Germany; Radboud Univ Nijmegen, Inst Water & Wetland Res, Dept Aquat Ecol & Environm Biol, NL-6525 ED Nijmegen, Netherlands.
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Cole, Jonathan J.
    Cary Inst Ecosyst Studies, Millbrook, NY USA.
    Bastos, Alex
    Univ Fed Espirito Santo, Dept Oceanog & Ecol, Vitoria, ES, Brazil.
    Albuquerque, Ana Luiza
    Univ Fed Fluminense, Dept Geoquim, Niteroi, RJ, Brazil.
    Cardoso, Simone J.
    Univ Fed Juiz de Fora, Aquat Ecol Lab, BR-36036900 Juiz De Fora, MG, Brazil.
    Roland, Fábio
    Univ Fed Juiz de Fora, Aquat Ecol Lab, BR-36036900 Juiz De Fora, MG, Brazil.
    Carbon Sequestration in a Large Hydroelectric Reservoir: An Integrative Seismic Approach2014In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 17, no 3, p. 430-441Article in journal (Refereed)
    Abstract [en]

    Artificial reservoirs likely accumulate more carbon than natural lakes due to their unusually high sedimentation rates. Nevertheless, the actual magnitude of carbon accumulating in reservoirs is poorly known due to a lack of whole-system studies of carbon burial. We determined the organic carbon (OC) burial rate and the total OC stock in the sediments of a tropical hydroelectric reservoir by combining a seismic survey with sediment core sampling. Our data suggest that no sediment accumulation occurs along the margins of the reservoir and that irregular bottom morphology leads to irregular sediment deposition. Such heterogeneous sedimentation resulted in high spatial variation in OC burial-from 0 to 209 g C m(-2) y(-1). Based on a regression between sediment accumulation and OC burial rates (R (2) = 0.94), and on the mean reservoir sediment accumulation rate (0.51 cm y(-1), from the seismic survey), the whole-reservoir OC burial rate was estimated at 42.2 g C m(-2) y(-1). This rate was equivalent to 70% of the reported carbon emissions from the reservoir surface to the atmosphere and corresponded to a total sediment OC accumulation of 0.62 Tg C since the reservoir was created. The approach we propose here allows an inexpensive and integrative assessment of OC burial in reservoirs by taking into account the high degree of spatial variability and based on a single assessment. Because burial can be assessed shortly after the survey, the approach combining a seismic survey and coring could, if applied on a larger scale, contribute to a more complete estimate of carbon stocks in freshwater systems in a relatively short period of time.

  • 388.
    Mendonca, Raquel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Univ Fed Juiz de Fora, Juiz De Fora, Brazil.
    Müller, Roger A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Clow, David
    US Geol Survey, Denver, USA.
    Verpoorter, Charles
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Univ Littoral Cote d´Opale, Univ Lille, Wimereux, France.
    Raymond, Peter
    Yale Sch Forestry & Environm Studies, New Haven, USA.
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Organic carbon burial in global lakes and reservoirs2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 1694Article in journal (Refereed)
    Abstract [en]

    Burial in sediments removes organic carbon (OC) from the short-term biosphere-atmosphere carbon (C) cycle, and therefore prevents greenhouse gas production in natural systems. Although OC burial in lakes and reservoirs is faster than in the ocean, the magnitude of inland water OC burial is not well constrained. Here we generate the first global-scale and regionally resolved estimate of modern OC burial in lakes and reservoirs, deriving from a compre- hensive compilation of literature data. We coupled statistical models to inland water area inventories to estimate a yearly OC burial of 0.15 (range, 0.06–0.25) Pg C, of which ~40% is stored in reservoirs. Relatively higher OC burial rates are predicted for warm and dry regions. While we report lower burial than previously estimated, lake and reservoir OC burial cor- responded to ~20% of their C emissions, making them an important C sink that is likely to increase with eutrophication and river damming.

  • 389.
    Mendonça, Raquel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Kosten, Sarian
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Cardoso, Simone Jaqueline
    Figueiredo-Barros, Marcos Paulo
    Estrada, Carlos Henrique Duque
    Roland, Fábio
    Organic carbon burial efficiency in a large tropical hydroelectric reservoir2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 11, p. 3331-3342Article in journal (Refereed)
    Abstract [en]

    Hydroelectric reservoirs bury significant amounts of organic carbon (OC) in their sediments. Many reservoirs are characterized by high sedimentation rates, low oxygen concentrations in bottom water and a high share of terrestrially derived OC, and all of these factors have been linked to a high efficiency of OC burial. However, investigations of OC burial efficiency (OCBE, i.e., the ratio between buried and deposited OC) in reservoirs are limited to a few studies, none of which include spatially resolved analyses. In this study we determined the spatial variation in OCBE in a large subtropical reservoir and related it to sediment characteristics. Our results show that the sediment accumulation rate explains up to 92 % of the spatial variability in OCBE, outweighing the effect of other variables, such as OC source and oxygen exposure time. OCBE at the pelagic sites varied from 48 to 86 % (mean 67 %) and decreased towards the dam. At the margins, OCBE was lower (9–17 %) due to the low sediment accumulation in shallow areas. Our data show that the variability in OCBE both along the rivers–dam and the margin–pelagic axes must be considered in whole-reservoir assessments. Combining these results with a spatially resolved assessment of sediment accumulation and OC burial in the studied reservoir, we estimated a spatially resolved mean OC burial efficiency of 57 %. Being the first assessment of OCBE with such a high spatial resolution in a reservoir, these results suggest that reservoirs may bury OC more efficiently than natural lakes.

  • 390.
    Mikolajewski, Dirk Johannes
    et al.
    Free Univ Berlin, Inst Biol, Berlin, Germany.
    Scharnweber, Kristin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Jiang, B
    Free Univ Berlin, Inst Biol, Berlin, Germany.
    Leicht, Sebastian
    Free Univ Berlin, Inst Biol, Berlin, Germany.
    Mauersberger, Rüdiger
    Forderverein Feldberg Uckermark Seenlandschaft eV, Templin, Germany.
    Johansson, Frank
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Changing the habitat: the evolution of inter-correlated traits to escape from predators2016In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 29, no 7, p. 1394-1405Article in journal (Refereed)
    Abstract [en]

    Burst escape speed is an effective and widely used behaviour for evading predators, with burst escape speed relying on several different morphological features. However, we know little about how behavioural and underlying morphological attributes change in concert as a response to changes in selective predation regime. We studied intercorrelated trait differentiation of body shape and burst-swim-mediating morphology in response to a habitat shift-related reduction in burst escape speed using larvae of the dragonfly genus Leucorrhinia. Species in this genus underwent a well-known habitat shift from predatory fish lakes (fish lakes) to predatory fish-free lakes dominated by large predatory dragonflies (dragonfly lakes) accompanied by relaxed selection on escape burst speed. Results revealed that species from fish lakes that possess faster burst speed have evolved a suite of functionally intercorrelated traits, expressing a wider abdomen, a higher abdominal muscles mass and a larger branchial chamber compared with species from dragonfly lakes. In contrast, populations within species did not show significant differences in muscle mass and branchial chamber size between lake types in three of the species. High multicollinearity among variables suggests that traits have evolved in concert rather than independently when Leucorrhinia shifted from fish lakes to dragonfly lakes. Thus, relaxed selection on burst escape speed in dragonfly-lake species resulted in a correlated reduction of abdominal muscles and a smaller branchial chamber, likely to save production and/or maintenance costs. Our results highlight the importance of studying integrated behavioural and morphological traits to fully understand the evolution of complex phenotypes.

  • 391.
    Milbrink, Göran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Vrede, Tobias
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Large-scale and long-term decrease in fish growth following the construction of hydroelectric reservoirs2011In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 68, no 12, p. 2167-2173Article in journal (Refereed)
    Abstract [en]

    Hydroelectric reservoirs retain large volumes of water and have a global impact on sea level, elemental cycles, and biodiversity. Using data from a total of 90 historical and recent surveys in nine regulated and eight unregulated alpine and subalpine lakes, we show an additional large effect of reservoirs, i.e., that impoundment causes drastically decreased fish growth and thereby great negative consequences for inland fisheries in Scandinavia. Following a long period (40-65 years) after impoundment, the length and mass of Arctic charr (Salvelinus alpinus) of the single age class 4+ years was, on average, 35% and 72% lower, respectively, in impounded versus natural lakes in northern Scandinavia. The effect was stronger at higher altitudes and can be mitigated by addition of inorganic nutrients. We suggest that the decreased fish growth is a consequence of lowered ecosystem productivity, oligotrophication, caused by impoundment, resulting in erosion and loss of the littoral ecosystem as well as delayed flooding and leakage of nutrients from the riparian zone until after the growing season.

  • 392.
    Monard, C.
    et al.
    Swedish Univ Agr Sci, Dept Forest Mycol & Plant Pathol, Uppsala BioCtr, POB 7026, SE-75007 Uppsala, Sweden; Univ Rennes 1, UMR ECOBIO 6553, OSUR, CNRS, F-35042 Rennes, France.
    Gantner, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Swedish Univ Agr Sci, Dept Forest Mycol & Plant Pathol, Uppsala BioCtr, POB 7026, SE-75007 Uppsala, Sweden; Rhein Akad Koln, Vogelsanger Str 295, D-50825 Cologne, Germany.
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Hallin, S.
    Swedish Univ Agr Sci, Dept Forest Mycol & Plant Pathol, Uppsala BioCtr, POB 7026, SE-75007 Uppsala, Sweden.
    Stenlid, J.
    Swedish Univ Agr Sci, Dept Forest Mycol & Plant Pathol, Uppsala BioCtr, POB 7026, SE-75007 Uppsala, Sweden.
    Habitat generalists and specialists in microbial communities across a terrestrial-freshwater gradient2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 37719Article in journal (Refereed)
    Abstract [en]

    Observations of distributions of microorganisms and their differences in community composition across habitats provide evidence of biogeographical patterns. However, little is known about the processes controlling transfers across habitat gradients. By analysing the overall microbial community composition (bacteria, fungi, archaea) across a terrestrial-freshwater gradient, the aim of this study was to understand the spatial distribution patterns of populations and identify taxa capable of crossing biome borders. Barcoded 454 pyrosequencing of taxonomic gene markers was used to describe the microbial communities in adjacent soil, freshwater and sediment samples and study the role of biotic and spatial factors in shaping their composition. Few habitat generalists but a high number of specialists were detected indicating that microbial community composition was mainly regulated by species sorting and niche partitioning. Biotic interactions within microbial groups based on an association network underlined the importance of ActinobacteriaSordariomycetesAgaricomycetes and Nitrososphaerales in connecting among biomes. Even if dispersion seemed limited, the shore of the lake represented a transition area, allowing populations to cross the biome boundaries. In finding few broadly distributed populations, our study points to biome specialization within microbial communities with limited potential for dispersal and colonization of new habitats along the terrestrial-freshwater continuum.

  • 393. Monard, Cecile
    et al.
    Gantner, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Stenlid, Jan
    Utilizing ITS1 and ITS2 to study environmental fungal diversity using pyrosequencing2013In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 84, no 1, p. 165-175Article in journal (Refereed)
    Abstract [en]

    The shorter reads generated by high-throughput sequencing has led to a focus on either the ITS1 or the ITS2 sublocus in fungal diversity analyses. Our study aimed to determine how making this choice would influence the datasets obtained and our vision of environmental fungal diversity. DNA was extracted from different environmental samples (water, sediments and soil) and the total internal transcribed spacer (ITS) locus was amplified. 454-sequencing was performed targeting both ITS1 and ITS2. No significant differences in the number of sequences, operational taxonomic units (OTUs) and in the dominant OTUs were detected but less diversity was observed in the ITS2 dataset. In the soil samples, differences in the fungal taxonomic identification were observed, with more Basidiomycota in the ITS1 dataset and more Ascomycota in the ITS2 dataset. Only one-third of the OTUs were detected in both datasets which could be due to (1) more short sequences removed in the ITS2 dataset, (2) different taxonomic affiliation depending on the sublocus used as BLASTn query and/or (3) selectivity in how a primer amplifies the true community. Although ITS1 and ITS2 datasets led to similar results at the fungal community level, for further in-depth diversity analysis this study suggests the analysis of both ITS regions, as they provided different information and were complementary.

  • 394.
    Mondav, Rhiannon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Development of an environmental functional gene microarray for soil microbial communities2010In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 76, no 21, p. 7161-7170Article in journal (Refereed)
    Abstract [en]

    Functional attributes of microbial communities are difficult to study, and most current techniques rely on DNA- and rRNA-based profiling of taxa and genes, including microarrays containing sequences of known microorganisms. To quantify gene expression in environmental samples in a culture-independent manner, we constructed an environmental functional gene microarray (E-FGA) consisting of 13,056 mRNA-enriched anonymous microbial clones from diverse microbial communities to profile microbial gene transcripts. A new normalization method using internal spot standards was devised to overcome spotting and hybridization bias, enabling direct comparisons of microarrays. To evaluate potential applications of this metatranscriptomic approach for studying microbes in environmental samples, we tested the E-FGA by profiling the microbial activity of agricultural soils with a low or high flux of N₂O. A total of 109 genes displayed expression that differed significantly between soils with low and high N₂O emissions. We conclude that mRNA-based approaches such as the one presented here may complement existing techniques for assessing functional attributes of microbial communities.

  • 395.
    Mondav, Rhiannon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia.
    McCalley, Carmody K
    Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA.
    Hodgkins, Suzanne B
    Department of Earth Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306-4320, USA.
    Frolking, Steve
    Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA.
    Saleska, Scott R
    Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
    Rich, Virginia I
    Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ 85721, USA.
    Chanton, Jeff P
    Department of Earth Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306-4320, USA.
    Crill, Patrick M
    Department of Geology and Geochemistry, Stockholm University, Stockholm 10691, Sweden.
    Microbial network, phylogenetic diversity and community membership in the active layer across a permafrost thaw gradient2017In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 19, no 8, p. 3201-3218Article in journal (Refereed)
    Abstract [en]

    Biogenic production and release of methane (CH4 ) from thawing permafrost has the potential to be a strong source of radiative forcing. We investigated changes in the active layer microbial community of three sites representative of distinct permafrost thaw stages at a palsa mire in northern Sweden. The palsa site (intact permafrost and low radiative forcing signature) had a phylogenetically clustered community dominated by Acidobacteria and Proteobacteria. The bog (thawing permafrost and low radiative forcing signature) had lower alpha diversity and midrange phylogenetic clustering, characteristic of ecosystem disturbance affecting habitat filtering. Hydrogenotrophic methanogens and Acidobacteria dominated the bog shifting from palsa-like to fen-like at the waterline. The fen (no underlying permafrost, high radiative forcing signature) had the highest alpha, beta and phylogenetic diversity, was dominated by Proteobacteria and Euryarchaeota and was significantly enriched in methanogens. The Mire microbial network was modular with module cores consisting of clusters of Acidobacteria, Euryarchaeota or Xanthomonodales. Loss of underlying permafrost with associated hydrological shifts correlated to changes in microbial composition, alpha, beta and phylogenetic diversity associated with a higher radiative forcing signature. These results support the complex role of microbial interactions in mediating carbon budget changes and climate feedback in response to climate forcing.

  • 396.
    Mondav, Rhiannon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Woodcroft, Ben J.
    Kim, Eun-Hae
    McCalley, Carmody K.
    Hodgkins, Suzanne B.
    Crill, Patrick M.
    Chanton, Jeffrey
    Hurst, Gregory B.
    VerBerkmoes, Nathan C.
    Saleska, Scott R.
    Hugenholtz, Philip
    Rich, Virginia I.
    Tyson, Gene W.
    Discovery of a novel methanogen prevalent in thawing permafrost2014In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 5, article id 3212Article in journal (Refereed)
    Abstract [en]

    Thawing permafrost promotes microbial degradation of cryo-sequestered and new carbon leading to the biogenic production of methane, creating a positive feedback to climate change. Here we determine microbial community composition along a permafrost thaw gradient in northern Sweden. Partially thawed sites were frequently dominated by a single archaeal phylotype, Candidatus ‘Methanoflorens stordalenmirensis’ gen. nov. sp. nov., belonging to the uncultivated lineage ‘Rice Cluster II’ (Candidatus ‘Methanoflorentaceae’ fam. nov.). Metagenomic sequencing led to the recovery of its near-complete genome, revealing the genes necessary for hydrogenotrophic methanogenesis. These genes are highly expressed and methane carbon isotope data are consistent with hydrogenotrophic production of methane in the partially thawed site. In addition to permafrost wetlands, ‘Methanoflorentaceae’ are widespread in high methane-flux habitats suggesting that this lineage is both prevalent and a major contributor to global methane production. In thawing permafrost, Candidatus ‘M. stordalenmirensis’ appears to be a key mediator of methane-based positive feedback to climate warming.

  • 397. Moss, Brian D.
    et al.
    Hering, Daniel
    Green, Andy J.
    Adoud, Ahmed
    Becares, Eloy
    Beklioglu, Meryem
    Bennion, Helen
    Boix, Dani
    Brucet, Sandra
    Carvalho, Laurence
    Clement, Bernard
    Davidson, Tom
    Declerck, Steven
    Dobson, Michael
    van Donk, Ellen
    Dudley, Bernard
    Feuchtmayr, Heidrun
    Friberg, Nikolai
    Grenouillet, Gael
    Hillebrand, Helmut
    Hobaek, Anders
    Irvine, Kenneth
    Jeppesen, Erik
    Johnson, Richard
    Jones, Iwan
    Kernan, Martin
    Lauridsen, Torben L.
    Manca, Marina
    Meerhof, Mariana
    Olafsson, Jon
    Ormerod, Steve
    Papastergiadou, Eva
    Penning, W.Ellis
    Ptacnik, Robert
    Quintana, Xavier
    Sandin, Leonard
    Seferlis, Miltiadis
    Simpson, Gavin
    Trigal, Cristina
    Verdonschot, Piet
    Verschoor, Antonie M.
    Weyhenmeyer, Gesa A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Climate change and the future of freshwater biodiversity in Europe: a primer for policy-makers2009In: Freshwater Reviews, ISSN 1755-084X, Vol. 2, no 2, p. 103-130Article in journal (Refereed)
    Abstract [en]

    Earth's climate is changing, and by the end of the 21st century in Europe, average temperatures are likely to have risen by at least 2 °C, and more likely 4 °C with associated effects on patterns of precipitation and the frequency of extreme weather events. Attention among policy-makers is divided about how to minimise the change, how to mitigate its effects, how to maintain the natural resources on which societies depend and how to adapt human societies to the changes. Natural systems are still seen, through a long tradition of conservation management that is largely species-based, as amenable to adaptive management, and biodiversity, mostly perceived as the richness of plant and vertebrate communities, often forms a focus for planning. We argue that prediction of particular species changes will be possible only in a minority of cases but that prediction of trends in general structure and operation of four generic freshwater ecosystems (erosive rivers, depositional floodplain rivers, shallow lakes and deep lakes) in three broad zones of Europe (Mediterranean, Central and Arctic-Boreal) is practicable. Maintenance and rehabilitation of ecological structures and operations will inevitably and incidentally embrace restoration of appropriate levels of species biodiversity. Using expert judgement, based on an extensive literature, we have outlined, primarily for lay policy makers, the pristine features of these systems, their states under current human impacts, how these states are likely to alter with a warming of 2 °C to 4 °C and what might be done to mitigate this. We have avoided technical terms in the interests of communication, and although we have included full referencing as in academic papers, we have eliminated degrees of detail that could confuse broad policy-making

     

  • 398.
    Mostovaya, Alina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Dissolved organic matter in lakes: Chemical diversity and continuum of reactivity2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Dissolved organic matter (DOM) is the largest pool of organic carbon in aquatic systems and an important component of the global carbon cycle. Large amounts of DOM are decomposed within lakes, resulting in fluxes of CO2 and CH4 to the atmosphere. Therefore, there is a considerable interest in understanding the controls of DOM decomposition in freshwaters. There is evidence that in lakes intrinsic controls related to DOM composition are of primary importance, yet our knowledge about molecular drivers of DOM degradation is limited. This thesis addresses the link between chemical composition and reactivity of lake DOM by applying an experimental approach, molecular-level DOM characterization, and kinetic modeling of DOM decay.

    The first study shows that photoinduced transformations and partial removal of colored aromatic components of DOM have profound effects on DOM degradation kinetics, mediated by the shifts in the relative share of rapidly and slowly degrading DOM fractions. Two following studies estimate exponential decay coefficients for each individual molecular formula identified within bulk DOM. A continuous distribution of exponential decay coefficients is found within bulk DOM, which directly corroborates the central and previously empirically untested assumption behind the reactivity continuum model of DOM decay. Further, individual decay rates are evaluated in connection to specific molecular properties. On average, highly unsaturated and phenolic compounds appear to be more persistent than compounds with higher aromatic content (plant polyphenols and polycondensed aromatics), and aliphatic compounds demonstrate the highest decay rates. The reactivity of aromatics additionally increases with increasing nominal oxidation state of carbon. Molecular analysis further indicates that increasing reactivity of DOM after UV exposure is caused by disintegration of supramolecular complexes. Study IV shows that changes in relative proportion of terrestrial versus algal DOM control degradability of DOM through seasons. Under ice, when algal-derived DOM is maximally depleted, DOM degradation potential converges to similarly low levels, regardless of lake type (productive or humic), and bacterial respiration primarily relies on terrestrial carbon. This suggests a general pattern of baseline metabolism across boreal lakes. I conclude that DOM is a dynamic reactivity continuum and a tight link exists between DOM behavior and compositional properties.

    List of papers
    1. Effects of compositional changes on reactivity continuum and decomposition kinetics of lake dissolved organic matter
    Open this publication in new window or tab >>Effects of compositional changes on reactivity continuum and decomposition kinetics of lake dissolved organic matter
    Show others...
    2016 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 7, p. 1733-1746Article in journal (Refereed) Published
    Abstract [en]

    To address the link between the composition and decomposition of freshwater dissolved organic matter (DOM), we manipulated the DOM from three boreal lakes using preincubations with UV light to cleave large aromatic molecules and polyvinylpyrrolidone (PVP) to remove colored phenolic compounds. Subsequently, we monitored the dissolved organic carbon (DOC) loss over 4months of microbial degradation in the dark to assess how compositional changes in DOM affected different aspects of the reactivity continuum, including the distribution of the apparent decay coefficients. We observed profound effects on decomposition kinetics, with pronounced shifts in the relative share of rapidly and more slowly decomposing fractions of the DOM. In the UV-exposed treatment initial apparent decay coefficient k(0) was almost threefold higher than in the control. Significantly higher relative DOC loss in the UV-exposed treatment was sustained for 2months of incubation, after which decay coefficients converged with those in the control. The PVP removed compounds with absorbance and fluorescence characteristics representative of aromatic compounds, which led to slower decomposition, compared to that in the control. Our results demonstrate the reactivity continuum underlying the decomposition of DOM in freshwaters and highlight the importance of intrinsic properties of DOM in determining its decomposition kinetics.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-304303 (URN)10.1002/2016JG003359 (DOI)000382581900002 ()
    Funder
    Swedish Research Council, 2011-3475-88773-67Knut and Alice Wallenberg Foundation
    Available from: 2016-10-04 Created: 2016-10-04 Last updated: 2017-11-30Bibliographically approved
    2. The emergence of the reactivity continuum of organic matter from kinetics of a multitude of individual molecular constituents
    Open this publication in new window or tab >>The emergence of the reactivity continuum of organic matter from kinetics of a multitude of individual molecular constituents
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Keywords
    dissolved organic matter, reactivity continuum model, FT-ICR-MS
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-316887 (URN)
    Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-03-08
    3. Molecular determinants of dissolved organic matter reactivity in lake water
    Open this publication in new window or tab >>Molecular determinants of dissolved organic matter reactivity in lake water
    2017 (English)In: Frontiers in Earth Science, ISSN 2296-6463, Vol. 5, article id 106Article in journal (Refereed) Published
    Abstract [en]

    Lakes in the boreal region have been recognized as the biogeochemical hotspots, yet many questions regarding the regulators of organic matter processing in these systems remain open. Molecular composition can be an important determinant of dissolved organic matter (DOM) fate in freshwater systems, but many aspects of this relationship remain unclear due to the complexity of DOM and its interactions in the natural environment. Here, we combine ultrahigh resolution mass spectrometry (FT-ICR-MS) with kinetic modeling of decay of \textgreater1,300 individual DOM molecular formulae identified by mass spectrometry, to evaluate the role of specific molecular characteristics in decomposition of lake water DOM. Our data is derived from a 4 months microbial decomposition experiment, carried out on water from three Swedish lakes, with the set-up including natural lake water, as well as the lake water pretreated with UV light. The relative decay rate of every molecular formula was estimated by fitting a single exponential model to the change in FT-ICR-MS signal intensities over decomposition time.We found a continuous range of exponential decay coefficients (kexp)within different groups of compounds and show that for highly unsaturated and phenolic compounds the distribution of kexp was shifted toward the lowest values. Contrary to this general trend, plant-derived polyphenols and polycondensed aromatics were on average more reactive than compounds with an intermediate aromaticity. The decay rate of aromatic compounds increased with increasing nominal oxidation state of carbon, and molecular mass in some cases showed an inverse relationship with kexp in the UV-manipulated treatment. Further, we observe an increase in formulae-specific kexp as a result of the UV pretreatment. General trends in reactivity identified among major compound groups emphasize the importance of the intrinsic controllers of lake water DOMdecay. However, we additionally indicate that each compound group contained a wide spectrum of reactivities, suggesting that high resolution is needed to further ascertain the complex reasons behind DOM reactivity in lake water.

    Place, publisher, year, edition, pages
    Frontiers Media S.A., 2017
    Keywords
    Dissolved organic matter, FT-ICR-MS, molecular composition, DOM degradation
    National Category
    Geology
    Identifiers
    urn:nbn:se:uu:diva-316890 (URN)10.3389/feart.2017.00106 (DOI)000419451700001 ()
    Funder
    Swedish Research Council, 2011-3475-88773-67Knut and Alice Wallenberg Foundation, KAW 2013.0091
    Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2019-06-05Bibliographically approved
    4. Seasonal variability in dissolved organic carbon degradation in boreal lakes: links to composition, sources, and baseline metabolism
    Open this publication in new window or tab >>Seasonal variability in dissolved organic carbon degradation in boreal lakes: links to composition, sources, and baseline metabolism
    (English)Manuscript (preprint) (Other academic)
    Keywords
    DOC, bacterioplankton, boreal lakes, seasonality, carbon source, baseline metabolism
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-316892 (URN)
    Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-03-08
  • 399.
    Mostovaya, Alina
    et al.
    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.
    Dittmar, Thorsten
    Carl von Ossietzky Univ Oldenburg, Inst Chem & Biol Marine Environm, Res Grp Marine Geochem MPI Bridging Grp, Oldenburg, Germany.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Molecular determinants of dissolved organic matter reactivity in lake water2017In: Frontiers in Earth Science, ISSN 2296-6463, Vol. 5, article id 106Article in journal (Refereed)
    Abstract [en]

    Lakes in the boreal region have been recognized as the biogeochemical hotspots, yet many questions regarding the regulators of organic matter processing in these systems remain open. Molecular composition can be an important determinant of dissolved organic matter (DOM) fate in freshwater systems, but many aspects of this relationship remain unclear due to the complexity of DOM and its interactions in the natural environment. Here, we combine ultrahigh resolution mass spectrometry (FT-ICR-MS) with kinetic modeling of decay of \textgreater1,300 individual DOM molecular formulae identified by mass spectrometry, to evaluate the role of specific molecular characteristics in decomposition of lake water DOM. Our data is derived from a 4 months microbial decomposition experiment, carried out on water from three Swedish lakes, with the set-up including natural lake water, as well as the lake water pretreated with UV light. The relative decay rate of every molecular formula was estimated by fitting a single exponential model to the change in FT-ICR-MS signal intensities over decomposition time.We found a continuous range of exponential decay coefficients (kexp)within different groups of compounds and show that for highly unsaturated and phenolic compounds the distribution of kexp was shifted toward the lowest values. Contrary to this general trend, plant-derived polyphenols and polycondensed aromatics were on average more reactive than compounds with an intermediate aromaticity. The decay rate of aromatic compounds increased with increasing nominal oxidation state of carbon, and molecular mass in some cases showed an inverse relationship with kexp in the UV-manipulated treatment. Further, we observe an increase in formulae-specific kexp as a result of the UV pretreatment. General trends in reactivity identified among major compound groups emphasize the importance of the intrinsic controllers of lake water DOMdecay. However, we additionally indicate that each compound group contained a wide spectrum of reactivities, suggesting that high resolution is needed to further ascertain the complex reasons behind DOM reactivity in lake water.

  • 400.
    Mostovaya, Alina
    et al.
    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.
    Koehler, Birgit
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Dittmar, Thorsten
    University of Oldenburg, Germany.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Emergence of the Reactivity Continuum of Organic Matter from Kinetics of a Multitude of Individual Molecular Constituents2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 20, p. 11571-11579Article in journal (Refereed)
    Abstract [en]

    The reactivity continuum (RC) model is a powerful statistical approach for describing the apparent kinetics of bulk organic matter (OM) decomposition. Here, we used ultrahigh resolution mass spectrometry data to evaluate the main premise of the RC model, namely that there is a continuous spectrum of reactivity within bulk OM, where each individual reactive type undergoes exponential decay. We performed a 120 day OM decomposition experiment on lake water, with an untreated control and a treatment preexposed to UV light, and described the loss of bulk dissolved organic carbon with RC modeling. The behavior of individual molecular formulas was described by fitting the single exponential model to the change in peak intensities over time. The range of the empirically derived apparent exponential decay coefficients (kexp) was indeed continuous. The character of the corresponding distribution, however, differed from the conceptual expectations, due to the effects of intrinsic averaging, overlaps in formula-specific loss and formation rates, and the limitation of the RC model to include apparently accumulating compounds in the analysis. Despite these limitations, both the RC model-simulated and empirical (mass spectrometry-derived) distributions of kexp captured the effects of preexposure to UV light. Overall, we present experimental evidence that the reactivity continuum within bulk OM emerges from a range of reactivity of numerous individual components. This constitutes direct empirical support for the major assumption behind the RC model of the natural OM decomposition.

567891011 351 - 400 of 664
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