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  • 1. Buehligen, Franziska
    et al.
    Lindner, Patrick
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Helmholtz Centre for Environmental Research – UFZ, Department of Environmental Microbiology, Germany.
    Stahl, Frank
    Scheper, Thomas
    Harms, Hauke
    Mueller, Susann
    Analysis of aging in lager brewing yeast during serial repitching2014In: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 187, p. 60-70Article in journal (Refereed)
    Abstract [en]

    Serial repitching of brewing yeast inoculates is an important economic factor in the brewing industry, as their propagation is time and resource intensive. Here, we investigated whether replicative aging and/or the population distribution status changed during serial repitching in three different breweries with the same brewing yeast strain but different abiotic backgrounds and repitching regimes with varying numbers of reuses. Next to bud scar numbers the DNA content of the Saccharomyces pastorianus HEBRU cells was analyzed. Gene expression patterns were investigated using low-density microarrays with genes for aging, stress, storage compound metabolism and cell cycle. Two breweries showed a stable rejuvenation rate during serial repitching. In a third brewery the fraction of virgin cells varied, which could be explained with differing wort aeration rates. Furthermore, the number of bud scars per cell and cell size correlated in all 3 breweries throughout all runs. Transcriptome analyses revealed that from the 6th run on, mainly for the cells positive gene expression could be seen, for example up-regulation of trehalose and glycogen metabolism genes. Additionally, the cells' settling in the cone was dependent on cell size, with the lowest and the uppermost cone layers showing the highest amount of dead cells. In general, cells do not progressively age during extended serial repitching.

  • 2. Buehligen, Franziska
    et al.
    Ruedinger, Philipp
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Helmholtz Association, Germany.
    Stahl, Frank
    Scheper, Thomas
    Harms, Hauke
    Mueller, Susann
    Sustainability of industrial yeast serial repitching practice studied by gene expression and correlation analysis2013In: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 168, no 4, p. 718-728Article in journal (Refereed)
    Abstract [en]

    Bottom-fermenting Saccharomyces pastorianus strains driving brewing fermentation processes are usually reused several times. It is still unclear, whether the number of successions may have an impact on cell physiology prompting consequences for brewing quality. In this study, fermentation performance of up to twenty consecutive runs in a brewery was investigated. For each run mRNA expression levels of cellular marker molecules, which are known to correlate with metabolism, hexose transport, aging processes, stress response mechanisms and flocculation capability was estimated to obtain information on changes in cell physiology over the successive runs. Low-density microarrays were used for this purpose and the resulting gene expression profiles were finally correlated with changes in the abiotic micro-environments. A surprising stability of the marker molecule expression profiles within each specific serial repitching was stated. Loss of flocculation or an advanced aging could not be detected during serial repitching in the analyzed brewery. However, certain runs of the serial repitchings showed high variation in stress response which was found to be caused by perturbations of the abiotic conditions. Regardless, the study showed that S. pastorianus can be used repeatedly in serial repitching processes without loss of prominent physiological characteristics.

  • 3.
    Downing, Andrea S.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Bhowmik, Avit
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Collste, David
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Université Clermont Auvergne, France.
    Cornell, Sarah E.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Donges, Jonathan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Häyhä, Tiina
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. International Institute for Applied Systems Analysis (IIASA), Austria.
    Hinton, Jennifer
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Université Clermont Auvergne, France.
    Lade, Steven
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Australian National University, Australia.
    Mooij, Wolf M.
    Matching scope, purpose and uses of planetary boundaries science2019In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 14, no 7, article id 073005Article, review/survey (Refereed)
    Abstract [en]

    Background: The Planetary Boundaries concept (PBc) has emerged as a key global sustainability concept in international sustainable development arenas. Initially presented as an agenda for global sustainability research, it now shows potential for sustainability governance. Weuse the fact that it is widely cited in scientific literature (>3500 citations) and an extensively studied concept to analyse how it has been used and developed since its first publication. Design: From the literature that cites the PBc, we select those articles that have the terms 'planetary boundaries' or 'safe operating space' in either title, abstract or keywords. Weassume that this literature substantively engages with and develops the PBc. Results: Wefind that 6% of the citing literature engages with the concept. Within this fraction of the literature we distinguish commentaries-that discuss the context and challenges to implementing the PBc, articles that develop the core biogeophysical concept and articles that apply the concept by translating to sub-global scales and by adding a human component to it. Applied literature adds to the concept by explicitly including society through perspectives of impacts, needs, aspirations and behaviours. Discussion: Literature applying the concept does not yet include the more complex, diverse, cultural and behavioural facet of humanity that is implied in commentary literature. Wesuggest there is need for a positive framing of sustainability goals-as a Safe Operating Space rather than boundaries. Key scientific challenges include distinguishing generalised from context-specific knowledge, clarifying which processes are generalizable and which are scalable, and explicitly applying complex systems' knowledge in the application and development of the PBc. We envisage that opportunities to address these challenges will arise when more human social dimensions are integrated, as we learn to feed the global sustainability vision with a plurality of bottom-up realisations of sustainability.

  • 4.
    Fetzer, Ingo
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Helmholtz Centre for Environmental Research – UFZ, Germany.
    Johst, Karin
    Schaewe, Robert
    Banitz, Thomas
    Harms, Hauke
    Chatzinotas, Antonis
    The extent of functional redundancy changes as species' roles shift in different environments2015In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 48, p. 14888-14893Article in journal (Refereed)
    Abstract [en]

    Assessing the ecological impacts of environmental change requires knowledge of the relationship between biodiversity and ecosystem functioning. The exact nature of this relationship can differ considerably between ecosystems, with consequences for the efficacy of species diversity as a buffer against environmental change. Using a microbial model system, we show that the relationship can vary depending on environmental conditions. Shapes suggesting functional redundancy in one environment can change, suggesting functional differences in another environment. We find that this change is due to shifting species roles and interactions. Species that are functionally redundant in one environment may become pivotal in another. Thus, caution is advised in drawing conclusions about functional redundancy based on a single environmental situation. It also implies that species richness is important because it provides a pool of species with potentially relevant traits. These species may turn out to be essential performers or partners in new interspecific interactions after environmental change. Therefore, our results challenge the generality of functional redundancy.

  • 5. Gharasoo, Mehdi
    et al.
    Centler, Florian
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. UFZ Helmholtz Center for Environmental Research, Germany.
    Thullner, Martin
    How the chemotactic characteristics of bacteria can determine their population patterns2014In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 69, p. 346-358Article in journal (Refereed)
    Abstract [en]

    Spatial distribution of soil microorganisms is relevant for the functioning and performance of many ecosystem processes such as nutrient cycling or biodegradation of organic matters and contaminants. Beside the multitude of abiotic environmental factors controlling the distribution of microorganisms in soil systems, many microbial species exhibit chemotactic behavior by directing their movement along concentration gradients of nutrients or of chemoattractants produced by cells of their own kind. This chemotactic ability has been shown to promote the formation of complex distribution patterns even in the absence of environmental heterogeneities. Microbial population patterns in heterogeneous soil systems might be, hence, the result of the interplay between the heterogeneous environmental conditions and the microorganisms' intrinsic pattern formation capabilities. In this modeling study, we combined an individual-based modeling approach with a reactive pore-network model to investigate the formation of bacterial patterns in homogeneous and heterogeneous porous media. We investigated the influence of different bacterial chemotactic sensitivities (toward both substrate and bacteria) on bacterial distribution patterns. The emerging population patterns were classified with the support of a geostatistical approach, and the required conditions for the formation of any specific pattern were analyzed. Results showed that the chemotactic behavior of the bacteria leads to non-trivial population patterns even in the absence of environmental heterogeneities. The presence of structural pore scale heterogeneities had also an impact on bacterial distributions. For a range of chemotactic sensitivities, microorganisms tend to migrate preferably from larger pores toward smaller pores and the resulting distribution patterns thus resembled the heterogeneity of the pore space. The results clearly indicated that in a porous medium like soil the distribution of bacteria may not only be related to the external constraints but also to the chemotactic behavior of the bacterial cells.

  • 6. Glaser, Karin
    et al.
    Kuppardt, Anke
    Boenigk, Jens
    Harms, Hauke
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Chatzinotas, Antonis
    The influence of environmental factors on protistan microorganisms in grassland soils along a land-use gradient2015In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 537, p. 33-42Article in journal (Refereed)
    Abstract [en]

    In this study, we investigated the effect of land use intensity, soil parameters and vegetation on protistan communities in grassland soils. We performed qualitative (T-RFLP) and quantitative (qPCR) analyses using primers specifically targeting the 18S rRNA gene for all Eukarya and for two common flagellate groups, i.e. the Chrysophyceae and the Kinetoplastea. Both approaches were applied to extracted soil DNA and RNA, in order to distinguish between the potentially active protists (i.e. RNA pool) and the total protistan communities, including potentially inactive and encysted cells (i.e. DNA pool). Several environmental determinants such as site, soil parameters and vegetation had an impact on the T-RFLP community profiles and the abundance of the quantified 18S rRNA genes. Correlating factors often differed between quantitative (qPCR) and qualitative (T-RFLP) approaches. For instance the Chrysophyceae/Eukarya 18S rDNA ratio as determined by qPCR correlated with the C/N ratio, whereas the community composition based on T-RLFP analysis was not affected indicating that both methods taken together provide a more complete picture of the parameters driving protist diversity. Moreover, distinct T-RFs were obtained, which could serve as potential indicators for either active organisms or environmental conditions like water content. While site was the main determinant across all investigated exploratories, land use seemed to be of minor importance for structuring protist communities. The impact of other parameters differed between the target groups, e.g. Kinetoplastea reacted on changes to water content on all sites, whereas Chrysophyceae were only affected in the Schorfheide. Finally, in most cases different responses were observed on RNA- and DNA-level, respectively. Vegetation for instance influenced the two flagellate groups only at the DNA-level across all sites. Future studies should thus include different protistan groups and also distinguish between active and inactive cells, in order to reveal causal shifts in community composition and abundance in agriculturally used systems.

  • 7. Koch, Christin
    et al.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. UFZ Helmholtz Center for Environmental Research, Germany.
    Harms, Hauke
    Mueller, Susann
    CHIC - An automated approach for the detection of dynamic variations in complex microbial communities2013In: Cytometry Part A, ISSN 1552-4922, E-ISSN 1552-4930, Vol. 83A, no 6, p. 561-567Article in journal (Refereed)
    Abstract [en]

    Altering environmental conditions change structures of microbial communities. These effects have an impact on the single-cell level and can be sensitively detected using community flow cytometry. However, although highly accurate, microbial monitoring campaigns are still rarely performed applying this technique. One reason is the limited access to pattern analysis approaches for the evaluation of microbial cytometric data. In this article, a new analyzing tool, Cytometric Histogram Image Comparison (CHIC), is presented, which realizes trend interpretation of variations in microbial community structures (i) without any previous definition of gates, by working (ii) person independent, and (iii) with low computational demand. Various factors influencing a sensitive determination of changes in community structures were tested. The sensitivity of this technique was found to discriminate down to 0.5% internal variation. The final protocol was exemplarily applied to a complex microbial community dataset, and correlations to experimental variation were successfully shown.

  • 8. Krohn, Sandra
    et al.
    Boehm, Stephan
    Engelmann, Cornelius
    Hartmann, Jan
    Brodzinski, Annika
    Chatzinotas, Antonis
    Zeller, Katharina
    Prywerek, Delia
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. UFZ Helmholtz Center for Environmental Research, Germany.
    Berg, Thomas
    Application of Qualitative and Quantitative Real-Time PCR, Direct Sequencing, and Terminal Restriction Fragment Length Polymorphism Analysis for Detection and Identification of Polymicrobial 16S rRNA Genes in Ascites2014In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 52, no 5, p. 1754-1757Article in journal (Refereed)
    Abstract [en]

    Qualitative and quantitative 16S rRNA gene-based real-time PCR and direct sequencing were applied for rapid detection and identification of bacterial DNA (bactDNA) in 356 ascites samples. bactDNA was detected in 35% of samples, with a mean of 3.24 log copies ml(-1). Direct sequencing of PCR products revealed 62% mixed chromatograms predominantly belonging to Grampositive bacteria. Terminal restriction fragment length polymorphism (T-RFLP) results of a sample subset confirmed sequence data showing polymicrobial DNA contents in 67% of bactDNA-positive ascites samples.

  • 9.
    Lade, Steven J.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Australian National University, Australia.
    Donges, Jonathan F.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Anderies, John M.
    Beer, Christian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cornell, Sarah E.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Gasser, Thomas
    Norberg, Jon
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Richardson, Katherine
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Steffen, Will
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing2018In: Earth System Dynamics, ISSN 2190-4979, E-ISSN 2190-4987, Vol. 9, no 2, p. 507-523Article in journal (Refereed)
    Abstract [en]

    Changes to climate-carbon cycle feedbacks may significantly affect the Earth system's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth system models. Here, we construct a stylised global climate-carbon cycle model, test its output against comprehensive Earth system models, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon cycle feedbacks and the operation of the carbon cycle. Specific results include that different feedback formalisms measure fundamentally the same climate-carbon cycle processes; temperature dependence of the solubility pump, biological pump, and CO2 solubility all contribute approximately equally to the ocean climate-carbon feedback; and concentration-carbon feedbacks may be more sensitive to future climate change than climate-carbon feedbacks. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the planetary boundaries, that are currently too uncertain to be included in comprehensive Earth system models.

  • 10. Lucas, Rico
    et al.
    Kuchenbuch, Anne
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Harms, Hauke
    Kleinsteuber, Sabine
    Long-term monitoring reveals stable and remarkably similar microbial communities in parallel full-scale biogas reactors digesting energy crops2015In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 91, no 3Article in journal (Refereed)
    Abstract [en]

    Biogas is an important renewable energy carrier. It is a product of stepwise anaerobic degradation of organic materials by highly diverse microbial communities forming complex interlinking metabolic networks. Knowledge about the microbial background of long-term stable process performance in full-scale reactors is crucial for rationally improving the efficiency and reliability of biogas plants. To generate such knowledge, in the present study three parallel mesophilic full-scale reactors fed exclusively with energy crops were sampled weekly over one year. Physicochemical process parameters were determined and the microbial communities were analysed by terminal restriction fragment length polymorphism (T-RFLP) fingerprinting and 454-amplicon sequencing. For investigating the methanogenic community, a high-resolution T-RFLP approach based on the mcrA gene was developed by selecting restriction enzymes with improved taxonomic resolution compared to previous studies. Interestingly, no Methanosarcina-related generalists, but rather specialized hydrogenotrophic and acetoclastic methanogenic taxa were detected. In general, the microbial communities in the non-connected reactors were remarkably stable and highly similar indicating that identical environmental and process parameters resulted in identical microbial assemblages and dynamics. Practical implications such as flexible operation schemes comprising controlled variations of process parameters for an efficient microbial resource management under fluctuating process conditions are discussed.

  • 11.
    Piemontese, Luigi
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Future Hydroclimatic Impacts on Africa: Beyond the Paris Agreement2019In: Earth's Future, ISSN 1384-5160, E-ISSN 2328-4277, Vol. 7, no 7, p. 748-761Article in journal (Refereed)
    Abstract [en]

    Projections of global warming in Africa are generally associated with increasing aridity and decreasing water availability. However, most freshwater assessments focus on single hydroclimatic indicators (e.g., runoff, precipitation, or aridity), lacking analysis on combined changes in evaporative demand, and water availability on land. There remains a high degree of uncertainty over water implications at the basin scale, in particular for the most water-consuming sector-food production. Using the Budyko framework, we perform an assessment of future hydroclimatic change for the 50 largest African basins, finding a consistent pattern of change in four distinct regions across the two main emission scenarios corresponding to the Paris Agreement, and the business as usual. Although the Paris Agreement is likely to lead to less intense changes when compared to the business as usual, both scenarios show the same pattern of hydroclimatic shifts, suggesting a potential roadmap for hydroclimatic adaptation. We discuss the social-ecological implications of the projected hydroclimatic shifts in the four regions and argue that climate policies need to be complemented by soil and water conservation practices to make the best use of future water resources.

  • 12. Richter, Stephan
    et al.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Thullner, Martin
    Centler, Florian
    Dittrich, Peter
    Towards rule-based metabolic databases: a requirement analysis based on KEGG2015In: International journal of data mining and bioinformatics, ISSN 1748-5673, Vol. 13, no 3, p. 289-319Article in journal (Refereed)
    Abstract [en]

    Knowledge of metabolic processes is collected in easily accessable online databases which are increasing rapidly in content and detail. Using these databases for the automatic construction of metabolic network models requires high accuracy and consistency. In this bipartite study we evaluate current accuracy and consistency problems using the KEGG database as a prominent example and propose design principles for dealing with such problems. In the first half, we present our computational approach for classifying inconsistencies and provide an overview of the classes of inconsistencies we identified. We detected inconsistencies both for database entries referring to substances and entries referring to reactions. In the second part, we present strategies to deal with the detected problem classes. We especially propose a rule-based database approach which allows for the inclusion of parameterised molecular species and parameterised reactions. Detailed case-studies and a comparison of explicit networks from KEGG with their anticipated rule-based representation underline the applicability and scalability of this approach.

  • 13. Saleem, Muhammad
    et al.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. UFZ Helmholtz Center for Environmental Research, Germany.
    Harms, Hauke
    Chatzinotas, Antonis
    Diversity of protists and bacteria determines predation performance and stability2013In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 7, no 10, p. 1912-1921Article in journal (Refereed)
    Abstract [en]

    Predation influences prey diversity and productivity while it effectuates the flux and reallocation of organic nutrients into biomass at higher trophic levels. However, it is unknown how bacterivorous protists are influenced by the diversity of their bacterial prey. Using 456 microcosms, in which different bacterial mixtures with equal initial cell numbers were exposed to single or multiple predators (Tetrahymena sp., Poterioochromonas sp. and Acanthamoeba sp.), we showed that increasing prey richness enhanced production of single predators. The extent of the response depended, however, on predator identity. Bacterial prey richness had a stabilizing effect on predator performance in that it reduced variability in predator production. Further, prey richness tended to enhance predator evenness in the predation experiment including all three protists predators (multiple predation experiment). However, we also observed a negative relationship between prey richness and predator production in multiple predation experiments. Mathematical analysis of potential ecological mechanisms of positive predator diversity-functioning relationships revealed predator complementarity as a factor responsible for both enhanced predator production and prey reduction. We suggest that the diversity at both trophic levels interactively determines protistan performance and might have implications in microbial ecosystem processes and services.

  • 14. Saleem, Muhammad
    et al.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Helmholtz Centre for Environmental Research - UFZ, Germany.
    Harms, Hauke
    Chatzinotas, Antonis
    Trophic complexity in aqueous systems: bacterial species richness and protistan predation regulate dissolved organic carbon and dissolved total nitrogen removal2016In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 283, no 1825, article id 20152724Article in journal (Refereed)
    Abstract [en]

    Loading of water bodies with dissolved organic carbon (DOC) and dissolved total nitrogen (DTN) affects their integrity and functioning. Microbial interactions mitigate the negative effects of high nutrient loads in these ecosystems. Despite numerous studies on how biodiversity mediates ecosystem functions, whether and how diversity and complexity of microbial food webs (horizontal, vertical) and the underlying ecological mechanisms influence nutrient removal has barely been investigated. Using microbial microcosms accommodating systematic combinations of prey (bacteria) and predator (protists) species, we showed that increasing bacterial richness improved the extent and reliability of DOC and DTN removal. Bacterial diversity drove nutrient removal either due to species foraging physiology or functional redundancy, whereas protistan diversity affected nutrient removal through bacterial prey resource partitioning and changing nutrient balance in the system. Our results demonstrate that prey predator diversity and trophic interactions interactively determine nutrient contents, thus implying the vital role of microbial trophic complexity as a biological buffer against DOC and DTN.

  • 15.
    Singh, Chandrakant
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Wang-Erlandsson, Lan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Delft University of Technology, The Netherlands.
    van der Ent, Ruud J.
    Assessing water stress dynamics of the Amazonian rainforest through rootzone storage capacity: A time-series approach2019In: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 21, article id EGU2019-8740-1Article in journal (Other academic)
    Abstract [en]

    Extended exposure to change in rainfall patterns and permanent land-use change (LUC) have reduced the capability of the forests to withstand any external stresses, also defined as forest resilience loss. Major parts of the Amazon forest is under threat of tipping towards a treeless savanna state due to these changes in rainfall patterns and LUC. This loss in forest resilience thus also prevents the forest to return to its pre-disturbed state of the natural cycle and makes the forest more prone to tipping. Yet, this change in natural cycle is not sudden and involves a certain time lag for the forest system to respond. Previous studies determined the forest resilience, but have only considered precipitation or climatological drought to be the key influencing factor. However, neither are a direct measure of the water stress of the forest and thus do not fully reflect the hydrological dynamics underlying forest resilience loss. This study addresses the research questions: (i) do change in climatic patterns have a significant effect on forest resilience?, (ii) how does the change in rainfall patterns orLUC affect the environmental dynamics of the forest over time?, (iii) whether the quantification of rainfall, rootzone storage capacity and LUC patterns at a temporal scale better for understanding the resilience loss of the forest?

    The present study aims at understanding the complex dynamics of the resilience of the forest system using a time-series approach. Advanced remote sensing resources allow us to determine and understand patterns in the tipping behaviour at a temporal scale as well as to understand the hydrological dynamics and environmental triggers. For this, we combined precipitation data, root zone storage capacity and satellite-based forest cover and LUC data analyzed along a time-series. This is to better represent the resilience loss of the forest towards hydrological interactions and also provide a better understanding of the hydrological process for the forest tipping rather than a statistical relation. Landsat-7 data is ideal for determining the forest change, due to its regional time-series availability from early 2000’s until today. This study provides a better understanding of the hydrological dynamics of the rainforest by utilizing a time-series approach. Root zone storage capacity represents the water stored in the roots of the forest (a.k.a., water available to the forest) and it is a much better representation for assessing water stress of the Amazonian rainforest than precipitation. Thus, also a better parameter for evaluating forest resilience loss over time.

  • 16.
    Steffen, Will
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Australian National University, Australia.
    Richardson, Katherine
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Cornell, Sarah E.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Bennett, Elena M.
    Biggs, Reinette
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stellenbosch University, South Africa .
    Carpenter, Stephen R.
    de Vries, Wim
    de Wit, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Folke, Carl
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Sweden.
    Gerten, Dieter
    Heinke, Jens
    Mace, Georgina M.
    Persson, Linn M.
    Ramanathan, Veerabhadran
    Reyers, Belinda
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Natural Resources and the Environment, CSIR, South Africa.
    Sörlin, Sverker
    Planetary boundaries: Guiding human development on a changing planet2015In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 347, no 6223Article in journal (Refereed)
    Abstract [en]

    The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries-climate change and biosphere integrity-have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.

  • 17.
    Steffen, Will
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Australian National University, Australia.
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Richardson, Katherine
    Lenton, Timothy M.
    Folke, Carl
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Royal Swedish Academy of Science, Sweden.
    Liverman, Diana
    Summerhayes, Colin P.
    Barnosky, Anthony D.
    Cornell, Sarah E.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Crucifix, Michel
    Donges, Jonathan F.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Lade, Steven J.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Australian National University, Australia.
    Scheffer, Marten
    Winkelmann, Ricarda
    Schellnhuber, Hans Joachim
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Australian National University, Australia.
    Trajectories of the Earth System in the Anthropocene2018In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 115, no 33, p. 8252-8259Article in journal (Refereed)
    Abstract [en]

    We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a Hothouse Earth pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System-biosphere, climate, and societies-and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.

  • 18. Stolpovsky, Konstantin
    et al.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. UFZ—Helmholtz Centre for Environmental Research, Germany.
    Van Cappellen, Philippe
    Thullner, Martin
    Influence of dormancy on microbial competition under intermittent substrate supply: insights from model simulations2016In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 92, no 6, article id fiw071Article in journal (Refereed)
    Abstract [en]

    Most natural environments are characterized by frequent changes of their abiotic conditions. Microorganisms can respond to such changes by switching their physiological state between activity and dormancy allowing them to endure periods of unfavorable abiotic conditions. As a consequence, the competitiveness of microbial species is not simply determined by their growth performance under favorable conditions but also by their ability and readiness to respond to periods of unfavorable environmental conditions. The present study investigates the relevance of factors controlling the abundance and activity of individual bacterial species competing for an intermittently supplied substrate. For this purpose, numerical experiments were performed addressing the response of microbial systems to regularly applied feeding pulses. Simulation results show that community dynamics may exhibit a non-trivial link to the frequency of the external constraints and that for a certain combination of these environmental conditions coexistence of species is possible. The ecological implication of our results is that even non-dominant, neglected species can have a strong influence on realized species composition of dominant key species, due to their invisible presence enable the coexistence between important key species and by this affecting provided function of the system.

  • 19. Tischer, Karolin
    et al.
    Kleinsteuber, Sabine
    Schleinitz, Kathleen M.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Helmholtz Centre for Environmental Research, Germany.
    Spott, Oliver
    Stange, Florian
    Lohse, Ute
    Franz, Janett
    Neumann, Franziska
    Gerling, Sarah
    Schmidt, Christian
    Hasselwander, Eyk
    Harms, Hauke
    Wendeberg, Annelie
    Microbial communities along biogeochemical gradients in a hydrocarbon-contaminated aquifer2013In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 15, no 9, p. 2603-2615Article in journal (Refereed)
    Abstract [en]

    Micro-organisms are known to degrade a wide range of toxic substances. How the environment shapes microbial communities in polluted ecosystems and thus influences degradation capabilities is not yet fully understood. In this study, we investigated microbial communities in a highly complex environment: the capillary fringe and subjacent sediments in a hydrocarbon-contaminated aquifer. Sixty sediment sections were analysed using terminal restriction fragment length polymorphism (T-RFLP) fingerprinting, cloning and sequencing of bacterial and archaeal 16S rRNA genes, complemented by chemical analyses of petroleum hydrocarbons, methane, oxygen and alternative terminal electron acceptors. Multivariate statistics revealed concentrations of contaminants and the position of the water table as significant factors shaping the microbial community composition. Micro-organisms with highest T-RFLP abundances were related to sulphate reducers belonging to the genus Desulfosporosinus, fermenting bacteria of the genera Sedimentibacter and Smithella, and aerobic hydrocarbon degraders of the genus Acidovorax. Furthermore, the acetoclastic methanogens Methanosaeta, and hydrogenotrophic methanogens Methanocella and Methanoregula were detected. Whereas sulphate and sulphate reducers prevail at the contamination source, the detection of methane, fermenting bacteria and methanogenic archaea further downstream points towards syntrophic hydrocarbon degradation.

  • 20.
    Wang-Erlandsson, Lan
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Delft University of Technology, The Netherlands; Research Institute for Humanity and Nature (RIHN), Japan.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Keys, Patrick W.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Colorado State University, USA.
    van der Ent, Ruud J.
    Savenije, Hubert H. G.
    Gordon, Line J.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Remote land use impacts on river flows through atmospheric teleconnections2018In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 22, no 8, p. 4311-4328Article in journal (Refereed)
    Abstract [en]

    The effects of land-use change on river flows have usually been explained by changes within a river basin. However, land-atmosphere feedback such as moisture recycling can link local land-use change to modifications of remote precipitation, with further knock-on effects on distant river flows. Here, we look at river flow changes caused by both land-use change and water use within the basin, as well as modifications of imported and exported atmospheric moisture. We show that in some of the world's largest basins, precipitation was influenced more strongly by land-use change occurring outside than inside the basin. Moreover, river flows in several non-transboundary basins were considerably regulated by land-use changes in foreign countries. We conclude that regional patterns of land-use change and moisture recycling are important to consider in explaining runoff change, integrating land and water management, and informing water governance.

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