| 1. |
- Ahlström, Hanna, et al.
(författare)
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An Earth system law perspective on governing social-hydrological systems in the Anthropocene
- 2021
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Ingår i: Earth System Governance. - : Elsevier BV. - 2589-8116. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The global hydrological cycle is characterized by complex interdependencies and self-regulating feedbacks that keep water in an ever-evolving state of flux at local, regional, and global levels. Increasingly, the scale of human impacts in the Anthropocene is altering the dynamics of this cycle, which presents additional challenges for water governance. Earth system law provides an important approach for addressing gaps in governance that arise from the mismatch between the global hydrological cycle and dispersed regulatory architecture across institutions and geographic regions. In this article, we articulate the potential for Earth system law to account for core hydrological problems that complicate water governance, including delay, redistribution, intertwinements, permanence, and scale. Through merging concepts from Earth system law with existing policy and legal principles, we frame an approach for addressing hydrological problems in the Anthropocene and strengthening institutional fit between established governance systems and the global hydrological cycle. We discuss how such an approach can be applied, and the challenges and implications for governing water as a cycle and complex social-hydrological system, both in research and practice.
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| 2. |
- Anderies, John M., et al.
(författare)
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A modeling framework for World-Earth system resilience : exploring social inequality and Earth system tipping points
- 2023
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Ingår i: Environmental Research Letters. - 1748-9326. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- The Anthropocene is characterized by the strengthening of planetary-scale interactions between the biophysical Earth system (ES) and human societies. This increasing social-ecological entanglement poses new challenges for studying possible future World-Earth system (WES) trajectories and World-Earth resilience defined as the capacity of the system to absorb and regenerate from anthropogenic stresses such as greenhouse gas emissions and land-use changes. The WES is currently in a non-equilibrium transitional regime of the early Anthropocene with arguably no plausible possibilities of remaining in Holocene-like conditions while sheltering up to 10 billion humans without risk of undermining the resilience of the ES. We develop a framework within which to conceptualize World-Earth resilience to examine this risk. Because conventional ball-and-cup type notions of resilience are hampered by the rapid and open-ended social, cultural, economic and technological evolution of human societies, we focus on the notion of 'pathway resilience', i.e. the relative number of paths that allow the WES to move from the currently occupied transitional states towards a safe and just operating space in the Anthropocene. We formalize this conceptualization mathematically and provide a foundation to explore how interactions between ES resilience (biophysical processes) and World system (WS) resilience (social processes) impact pathway resilience. Our analysis shows the critical importance of building ES resilience to reach a safe and just operating space. We also illustrate the importance of WS dynamics by showing how perceptions of fairness coupled with regional inequality affects pathway resilience. The framework provides a starting point for the analysis of World-Earth resilience that can be extended to more complex model settings as well as the development of quantitative planetary-scale resilience indicators to guide sustainable development in a stabilized ES.
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| 3. |
- Armstrong McKay, David I., et al.
(författare)
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Exceeding 1.5°C global warming could trigger multiple climate tipping points
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 377:6611
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Tidskriftsartikel (refereegranskat)abstract
- Climate tipping points occur when change in a part of the climate system becomes self-perpetuating beyond a warming threshold, leading to substantial Earth system impacts. Synthesizing paleoclimate, observational, and model-based studies, we provide a revised shortlist of global “core” tipping elements and regional “impact” tipping elements and their temperature thresholds. Current global warming of ~1.1°C above preindustrial temperatures already lies within the lower end of some tipping point uncertainty ranges. Several tipping points may be triggered in the Paris Agreement range of 1.5 to <2°C global warming, with many more likely at the 2 to 3°C of warming expected on current policy trajectories. This strengthens the evidence base for urgent action to mitigate climate change and to develop improved tipping point risk assessment, early warning capability, and adaptation strategies.
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| 4. |
- Basnet, Shyam, et al.
(författare)
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Organic agriculture in a low-emission world : exploring combined measures to deliver a sustainable food system in Sweden
- 2023
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Ingår i: Sustainability Science. - : Springer Science and Business Media LLC. - 1862-4065 .- 1862-4057. ; 18:1, s. 501-519
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Tidskriftsartikel (refereegranskat)abstract
- In the EU, including Sweden, organic farming is seen as a promising pathway for sustainable production, protecting human health and animal welfare, and conserving the environment. Despite positive developments in recent decades, expanding organic farming to the Swedish national target of 30% of farmland under organic production remains challenging. In this study, we developed two scenarios to evaluate the role of organic farming in the broader context of Swedish food systems: (i) baseline trend scenario (Base), and (ii) sustainable food system scenario (Sust). Base describes a future where organic farming is implemented alongside the current consumption, production and waste patterns, while Sust describes a future where organic farming is implemented alongside a range of sustainable food system initiatives. These scenarios are coupled with several variants of organic area: (i) current 20% organic area, (ii) the national target of 30% organic area by 2030, and (iii) 50% organic area by 2050 for Sust. We applied the ‘FABLE (Food, Agriculture, Biodiversity, Land-use and Energy) Calculator’ to assess the evolution of the Swedish food system from 2000 to 2050 and evaluate land use, emissions and self-sufficiency impacts under these scenarios. Our findings show that expanding organic farming in the Base scenarios increases the use of cropland and agricultural emissions by 2050 compared to the 2010 reference year. However, cropland use and emissions are reduced in the Sust scenario, due to dietary changes, reduction of food waste and improved agricultural productivity. This implies that there is room for organic farming and the benefits it provides, e.g. the use of fewer inputs and improved animal welfare in a sustainable food system. However, changing towards organic agriculture is only of advantage when combined with transformative strategies to promote environmental sustainability across multiple sections, such as changed consumption, better production and food waste practices.
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| 5. |
- Buehligen, Franziska, et al.
(författare)
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Analysis of aging in lager brewing yeast during serial repitching
- 2014
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 187, s. 60-70
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 6. |
- Buehligen, Franziska, et al.
(författare)
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Sustainability of industrial yeast serial repitching practice studied by gene expression and correlation analysis
- 2013
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 168:4, s. 718-728
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Centler, Florian, et al.
(författare)
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Keystone Species and Modularity in Microbial Hydrocarbon Degradation Uncovered by Network Analysis and Association Rule Mining
- 2020
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Ingår i: Microorganisms. - : MDPI AG. - 2076-2607. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Natural microbial communities in soils are highly diverse, allowing for rich networks of microbial interactions to unfold. Identifying key players in these networks is difficult as the distribution of microbial diversity at the local scale is typically non-uniform, and is the outcome of both abiotic environmental factors and microbial interactions. Here, using spatially resolved microbial presence-absence data along an aquifer transect contaminated with hydrocarbons, we combined co-occurrence analysis with association rule mining to identify potential keystone species along the hydrocarbon degradation process. Derived co-occurrence networks were found to be of a modular structure, with modules being associated with specific spatial locations and metabolic activity along the contamination plume. Association rules identify species that never occur without another, hence identifying potential one-sided cross-feeding relationships. We find that hub nodes in the rule network appearing in many rules as targets qualify as potential keystone species that catalyze critical transformation steps and are able to interact with varying partners. By contrasting analysis based on data derived from bulk samples and individual soil particles, we highlight the importance of spatial sample resolution. While individual inferred interactions are hypothetical in nature, requiring experimental verification, the observed global network patterns provide a unique first glimpse at the complex interaction networks at work in the microbial world.
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| 8. |
- Chrysafi, Anna, et al.
(författare)
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Quantifying Earth system interactions for sustainable food production via expert elicitation
- 2022
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Ingår i: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 5:10, s. 830-842
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Tidskriftsartikel (refereegranskat)abstract
- Several safe boundaries of critical Earth system processes have already been crossed due to human perturbations; not accounting for their interactions may further narrow the safe operating space for humanity. Using expert knowledge elicitation, we explored interactions among seven variables representing Earth system processes relevant to food production, identifying many interactions little explored in Earth system literature. We found that green water and land system change affect other Earth system processes strongly, while land, freshwater and ocean components of biosphere integrity are the most impacted by other Earth system processes, most notably blue water and biogeochemical flows. We also mapped a complex network of mechanisms mediating these interactions and created a future research prioritization scheme based on interaction strengths and existing knowledge gaps. Our study improves the understanding of Earth system interactions, with sustainability implications including improved Earth system modelling and more explicit biophysical limits for future food production.
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| 9. |
- Crona, Beatrice, et al.
(författare)
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Going beyond carbon : An Earth system impact score to better capture corporate and investment impacts on the earth system
- 2023
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Ingår i: Journal of Cleaner Production. - 0959-6526 .- 1879-1786. ; 429
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Tidskriftsartikel (refereegranskat)abstract
- Corporations are responsible for a significant portion of observed impacts on the Earth system, including greenhouse gas (GHG) emissions, but also water extraction, landuse change and other pressures on nature. These nature-related impacts are essential to consider and capture because they have local impacts on a range of ecosystem functions on which companies and economies depend, but they also fundamentally affect our ability to mitigate and adapt to a changing climate. Furthermore, climate, land and water interact and affect each other in various ways, such that climate change can be exacerbated by degraded ecosystems, which in turn are dependent on water. This paper tests a novel metric developed to capture corporate Earth system impact (ESI) beyond merely direct GHG emissions and explores how such a tool could be used to improve assessments of corporate environmental impacts and support decisions on where to direct public and private investments. We use the mining sector as a test case to illustrate the applicability of the ESI score and examine the impact of the the five largest (by market cap) mining companies in the precious metal mining sector and the top five in the non-precious metal mining sector. We find that many of the mining assets have non-negligible impacts on land and water, and we show that the ESI metric identifies a different set of asset for targeted action than conventional carbon intensity scores would do.
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| 10. |
- Downing, Andrea S., et al.
(författare)
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Matching scope, purpose and uses of planetary boundaries science
- 2019
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 14:7
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Forskningsöversikt (refereegranskat)abstract
- 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.
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| 11. |
- Fetzer, Ingo, et al.
(författare)
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The extent of functional redundancy changes as species' roles shift in different environments
- 2015
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:48, s. 14888-14893
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 12. |
- Gerten, Dieter, et al.
(författare)
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Feeding ten billion people is possible within four terrestrial planetary boundaries
- 2020
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Ingår i: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 3:3, s. 200-208
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Tidskriftsartikel (refereegranskat)abstract
- Global agriculture puts heavy pressure on planetary boundaries, posing the challenge to achieve future food security without compromising Earth system resilience. On the basis of process-detailed, spatially explicit representation of four interlinked planetary boundaries (biosphere integrity, land-system change, freshwater use, nitrogen flows) and agricultural systems in an internally consistent model framework, we here show that almost half of current global food production depends on planetary boundary transgressions. Hotspot regions, mainly in Asia, even face simultaneous transgression of multiple underlying local boundaries. If these boundaries were strictly respected, the present food system could provide a balanced diet (2,355 kcal per capita per day) for 3.4 billion people only. However, as we also demonstrate, transformation towards more sustainable production and consumption patterns could support 10.2 billion people within the planetary boundaries analysed. Key prerequisites are spatially redistributed cropland, improved water-nutrient management, food waste reduction and dietary changes. Agriculture transforms the Earth and risks crossing thresholds for a healthy planet. This study finds almost half of current food production crosses such boundaries, as for freshwater use, but that transformation towards more sustainable production and consumption could support 10.2 billion people.
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| 13. |
- Gharasoo, Mehdi, et al.
(författare)
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How the chemotactic characteristics of bacteria can determine their population patterns
- 2014
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 69, s. 346-358
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 14. |
- Glaser, Karin, et al.
(författare)
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The influence of environmental factors on protistan microorganisms in grassland soils along a land-use gradient
- 2015
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 537, s. 33-42
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 15. |
- Gleeson, Tom, et al.
(författare)
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Illuminating water cycle modifications and Earth system resilience in the Anthropocene
- 2020
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Ingår i: Water resources research. - 0043-1397 .- 1944-7973. ; 56:4
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Tidskriftsartikel (refereegranskat)abstract
- Fresh water—the bloodstream of the biosphere—is at the center of the planetary drama of the Anthropocene. Water fluxes and stores regulate the Earth's climate and are essential for thriving aquatic and terrestrial ecosystems, as well as water, food, and energy security. But the water cycle is also being modified by humans at an unprecedented scale and rate. A holistic understanding of freshwater's role for Earth system resilience and the detection and monitoring of anthropogenic water cycle modifications across scales is urgent, yet existing methods and frameworks are not well suited for this. In this paper we highlight four core Earth system functions of water (hydroclimatic regulation, hydroecological regulation, storage, and transport) and key related processes. Building on systems and resilience theory, we review the evidence of regional‐scale regime shifts and disruptions of the Earth system functions of water. We then propose a framework for detecting, monitoring, and establishing safe limits to water cycle modifications and identify four possible spatially explicit methods for their quantification. In sum, this paper presents an ambitious scientific and policy grand challenge that could substantially improve our understanding of the role of water in the Earth system and cross‐scale management of water cycle modifications that would be a complementary approach to existing water management tools.
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| 16. |
- Jacob, Ute, et al.
(författare)
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The Role of Body Size in Complex Food Webs : A Cold Case
- 2011
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Ingår i: Advances in Ecological Research. - : Elsevier. - 0065-2504 .- 2163-582X. ; 45, s. 181-223
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Tidskriftsartikel (refereegranskat)abstract
- Human-induced habitat destruction, overexploitation, introduction of alien species and climate change are causing species to go extinct at unprecedented rates, from local to global scales. There are growing concerns that these kinds of disturbances alter important functions of ecosystems. Our current understanding is that key parameters of a community (e.g. its functional diversity, species composition, and presence/absence of vulnerable species) reflect an ecological network’s ability to resist or rebound from change in response to pressures and disturbances, such as species loss. If the food web structure is relatively simple, we can analyse the roles of different species interactions in determining how environmental impacts translate into species loss. However, when ecosystems harbour species-rich communities, as is the case in most natural systems, then the complex network of ecological interactions makes it a far more challenging task to perceive how species’ functional roles influence the consequences of species loss. One approach to deal with such complexity is to focus on the functional traits of species in order to identify their respective roles: for instance, large species seem to be more susceptible to extinction than smaller species. Here, we introduce and analyse the marine food web from the high Antarctic Weddell Sea Shelf to illustrate the role of species traits in relation to network robustness of this complex food web. Our approach was threefold: firstly, we applied a new classification system to all species, grouping them by traits other than body size; secondly, we tested the relationship between body size and food web parameters within and across these groups and finally, we calculated food web robustness. We addressed questions regarding (i) patterns of species functional/trophic roles, (ii) relationships between species functional roles and body size and (iii) the role of species body size in terms of network robustness. Our results show that when analyzing relationships between trophic structure, body size and network structure, the diversity of predatory species types needs to be considered in future studies.
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| 17. |
- Keys, Patrick W., et al.
(författare)
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Invisible water security : Moisture recycling and water resilience
- 2019
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Ingår i: Water Security. - : Elsevier BV. - 2468-3124. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Water security is key to planetary resilience for human society to flourish in the face of global change. Atmospheric moisture recycling – the process of water evaporating from land, flowing through the atmosphere, and falling out again as precipitation over land – is the invisible mechanism by which water influences resilience, that is the capacity to persist, adapt, and transform. Through land-use change, mainly by agricultural expansion, humans are destabilizing and modifying moisture recycling and precipitation patterns across the world. Here, we provide an overview of how moisture recycling changes may threaten tropical forests, dryland ecosystems, agriculture production, river flows, and water supplies in megacities, and review the budding literature that explores possibilities to more consciously manage and govern moisture recycling. Novel concepts such as the precipitationshed allows for the source region of precipitation to be understood, addressed and incorporated in existing water resources tools and sustainability frameworks. We conclude that achieving water security and resilience requires that we understand the implications of human influence on moisture recycling, and that new research is paving the way for future possibilities to manage and mitigate potentially catastrophic effects of land use and water system change.
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| 18. |
- Koch, Christin, et al.
(författare)
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CHIC - An automated approach for the detection of dynamic variations in complex microbial communities
- 2013
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Ingår i: Cytometry Part A. - : Wiley. - 1552-4922 .- 1552-4930. ; 83A:6, s. 561-567
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 19. |
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| 20. |
- Lade, Steven J., et al.
(författare)
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A prototype Earth system impact metric that accounts for cross-scale interactions
- 2021
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 16:11
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Tidskriftsartikel (refereegranskat)abstract
- Human activities are disrupting the Earth system's biophysical processes, which underlie human wellbeing. The planetary boundary framework sets 'safe' global limits on these pressures, but a sub-global assessment of these pressures, their interactions and subsequent systemic effects is needed to enable corporate and public entities to assess the systemic environmental impacts of their decisions. Here, we developed a prototype Earth system impact metric that is savvy to Earth system interactions. First, we quantified sub-global interactions between climate change, surface water runoff, and vegetation cover using the global dynamic vegetation model LPJmL (Lund-Potsdam-Jena managed Land). Second, we used a feedback model to study how these interactions amplify environmental impacts. We found, for example, that interactions more than double the Earth system impacts of deforestation in some tropical forests. Finally, we combined these amplification factors with an assessment of the current state of the Earth system to create a prototype Earth system impact metric. We envision that future versions of our prototype metric will allow corporate and public actors to better assess the systemic environmental impacts of their decisions. Our ambition is that these results catalyse further scientific work to extend and improve this metric, as well as action by investors, companies, cities, and governments to deliver sustainable outcomes across the private and public sectors.
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| 21. |
- Lade, Steven J., et al.
(författare)
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Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing
- 2018
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Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 9:2, s. 507-523
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 22. |
- Lucas, Rico, et al.
(författare)
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Long-term monitoring reveals stable and remarkably similar microbial communities in parallel full-scale biogas reactors digesting energy crops
- 2015
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 91:3
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 23. |
- Nyasulu, Maganizo Kruger, 1988-
(författare)
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A Triply Green Revolution : Building water resilience for SDGs on food and poverty for Africa
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sub-Saharan Africa is confronted with the urgent challenge of ensuring food security in the face of changing demographics, climate change and water vulnerability, which can lead to potential crop failure. Despite the high advocacy for technological solutions, such as irrigation, rainfed agricultural systems, which account for more than 90% of the region's food production, often remain overlooked. This raises the question of which water sources can be sustainably utilized to meet the Sustainable Development Goals. This thesis investigates the significant role of "green water" in addressing these challenges in agricultural production and ecosystem health in the sub-Saharan African region. Application of models reveal the pronounced role of green water in African forest systems, regional ecosystems, and food production systems in studying these societal sustainability questions,. The study projects a decrease in precipitation recycling with increasing severity of climate change. The results suggests that regions with lower water efficiency per yield production can significantly increase agricultural yield by tapping into green water sources as improving rainwater management systems, even as land-sourced precipitation is projected to decline more than oceanic sources. The thesis argues for adoption of a green water-centric approach to be opted in strategic plans at both local and global levels. Moreover, by capitalizing on green water resources, less developed nations such as sub-Saharan Africa can fulfill their Sustainable Development Goals without the need for significant technological investments and the associated environmental risks.
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| 24. |
- Nyasulu, Maganizo Kruger, 1988-, et al.
(författare)
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African rainforest moisture contribution to continental agricultural water consumption
- 2024
-
Ingår i: Agricultural and Forest Meteorology. - 0168-1923 .- 1873-2240. ; 346
-
Tidskriftsartikel (refereegranskat)abstract
- Precipitation is essential for food production in Sub-Saharan Africa, where more than 80 % of agriculture is rainfed. Although ∼40 % of precipitation in certain regions is recycled moisture from Africa's tropical rainforest, there needs to be more knowledge about how this moisture supports the continent's agriculture. In this study, we quantify all moisture sources for agrarian precipitation (African agricultural precipitationshed), the estimates of African rainforest's moisture contribution to agricultural precipitation, and the evaporation from agricultural land across the continent. Applying a moisture tracking model (UTRACK) and a dynamic global vegetation model (LPJmL), we find that the Congo rainforest (>60 % tree cover) is a crucial moisture source for many agricultural regions. Although most of the rainforest acreage is in the DRC, many neighboring nations rely significantly on rainforest moisture for their rainfed agriculture, and even in remote places, rainforest moisture accounts for ∼10–20 % of agricultural water use. Given continuous deforestation and climate change, which impact rainforest areas and resilience, more robust governance for conserving the Congo rainforest is necessary to ensure future food production across multiple Sub-Saharan African countries.
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| 25. |
- Nyasulu, Maganizo Kruger, 1988-
(författare)
-
Green-Blue Water Potential: : Building water resilience to attain the SDGs on food and poverty in Africa
- 2023
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Attaining the Sustainable Development Goals (SDGs) of eradicating hunger and securing sustainable food for all by 2030, constitutes a major global challenge, particularly in sub-Saharan Africa (SSA). Here, malnourishment, poverty, and population growth are among the highest in the world, and some regions are constantly subject to extreme water variability and scarcity. Multiple elements are at play to attain the SDGs: governance, availability of soil nutrients and farming mechanisms and inputs, peace, human rights, gender equity, and above all, the availability of water for food production. The key question is: how much water is required and available to attain the SDGs in SSA? The proposed research is an analysis of the pathways for assessing how much blue (surface runoff and groundwater) and green water (infiltrated rain in soil supporting rainfed farming) is required, available, and possible to manage in ways that build water resilience in Sub-Saharan Africa (SSA) to attain the Sustainable Development Goals (SDGs). More than 95% of the agriculture in this region depends on rain-fed water. Therefore, understanding pathways for building blue-green water resilience will be pivotal to long-term water, agriculture, and ecosystem management for strategic decision-making in African regions and countries. This study is a step towards rectifying three pressing questions that will inevitably build on water resilience for sustainable intensification of agriculture in SSA. These are: ● Q1: What type, where, and how much water is available and required for agricultural production? ● Q2: What are the green water management pathways possible to attain the SDGs on food security and advance a triply green revolution? ● Q3: What are the synergies and trade-offs in strategies to secure green and blue water for food while building water resilience in SSA? The licentiate will focus on discussions of Papers I and 2 and an overview of future manuscripts. In paper I, I analyse the role of the rainforest's moisture contribution to agricultural land across Africa. The paper expanded to establish key sources of precipitation that downwind in agricultural land. I found rainforest moisture contribution to agriculture systems is significant in space (regions within rainforest vicinity) and time (dry seasons), with about 10–40% recycling contribution.Paper II Here we develop a detailed mapping of green and blue water flows, resources, and soil moisture feedback using a hydroclimatic regime framework. This level of water mapping is crucial for targeted water management in agriculture in either green or blue water-dominated landscapes. Our results show that both big African food baskets (the Sahel region) and historically water-vulnerable agricultural regions will experience intensive hydroclimatic changes that directly affect agricultural production (SDG 2) and economic returns for smallholder farmers (SDG 1). In my thesis, I will focus on applying green water management in croplands residing in changing hydrological regimes to assess the impact on yield production, social-environmental consequences, and contribution to SDGs. Further, I intend to expand the work within the green water planetary boundary (GPB) to assess the climatic impact of transgressing the GPB on food production and ecosystems both during wet and dry departures. Here we will further explore the question of trade-offs between nature and society and the positive synergies in the shift of the hydro-climatic cycle and moisture feedback for current and future rainfed food production in Africa.
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| 26. |
- Piemontese, Luigi, 1988-, et al.
(författare)
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Estimating the global potential of water harvesting from successful case studies
- 2020
-
Ingår i: Global Environmental Change. - : Elsevier BV. - 0959-3780 .- 1872-9495. ; 63
-
Tidskriftsartikel (refereegranskat)abstract
- Water harvesting has been widely applied in different social-ecological contexts, proving to be a valuable approach to sustainable intensification of agriculture. Global estimates of the potential of water harvesting are generally based on purely biophysical assessments and mostly neglect the socioeconomic dimension of agriculture. This neglect becomes a critical factor for the feasibility and effectiveness of policy and funding efforts to mainstream this practice. This study uses archetype analysis to systematically identify social-ecological regions worldwide based on >160 successful cases of local water harvesting implementation. We delineate six archetypal regions which capture the specific social-ecological conditions of the case studies. The archetypes cover 19% of current global croplands with hotspots in large portions of East Africa and Southeast Asia. We estimate that the adoption of water harvesting in these cropland areas can increase crop production up to 60–100% in Uganda, Burundi, Tanzania and India. The results of this study can complement conventional biophysical analysis on the potential of these practices and guide policy development at global and regional scales. The methodological approach can be also replicated at finer scales to guide the improvement of rainfed agricultural.
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| 27. |
- Piemontese, Luigi, et al.
(författare)
-
Future Hydroclimatic Impacts on Africa : Beyond the Paris Agreement
- 2019
-
Ingår i: Earth's Future. - 2328-4277. ; 7:7, s. 748-761
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 28. |
- Pranindita, Agnes, et al.
(författare)
-
Moisture recycling and the potential role of forests as moisture source during European heatwaves
- 2021
-
Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 58:1-2, s. 609-624
-
Tidskriftsartikel (refereegranskat)abstract
- Heatwaves are extreme weather events that have become more frequent and intense in Europe over the past decades. Heatwaves are often coupled to droughts. The combination of them lead to severe ecological and socio-economic impacts. Heatwaves can self-amplify through internal climatic feedback that reduces local precipitation. Understanding the terrestrial sources of local precipitation during heatwaves might help identify mitigation strategies on land management and change that alleviate impacts. Moisture recycling of local water sources through evaporation allows a region to maintain precipitation in the same region or, by being transported by winds, in adjacent regions. To understand the role of terrestrial moisture sources for sustaining precipitation during heatwaves, we backtrack and analyse the precipitation sources of Northern, Western, and Southern sub-regions across Europe during 20 heatwave periods between 1979 and 2018 using the moisture tracking model Water Accounting Model-2layers (WAM-2layers). In Northern and Western Europe, we find that stabilizing anticyclonic patterns reduce the climatological westerly supply of moisture, mainly from the North Atlantic Ocean, and enhances the moisture flow from the eastern Euro-Asian continent and from within their own regions-suggesting over 10% shift of moisture supply from oceanic to terrestrial sources. In Southern Europe, limited local moisture sources result in a dramatic decrease in the local moisture recycling rate. Forests uniformly supply additional moisture to all regions during heatwaves and thus contribute to buffer local impacts. This study suggests that terrestrial moisture sources, especially forests, may potentially be important to mitigate moisture scarcity during heatwaves in Europe.
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| 29. |
- Renes, Sophia Elise, et al.
(författare)
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Disturbance history can increase functional stability in the face of both repeated disturbances of the same type and novel disturbances - dataset
- 2020
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
-
Annan publikationabstract
- Climate change is expected to increase the incidences of extremes in environmental conditions. To investigate how repeated disturbances affect microbial ecosystem resistance, natural lake bacterioplankton communities were subjected to repeated temperature disturbances of two intensities (25 °C and 35 °C), and subsequently to an acidification event. We measured functional parameters (bacterial production, abundance, extracellular enzyme activities) and community composition parameters (richness, evenness, niche width) and found that, compared to undisturbed control communities, the 35 °C treatment was strongly affected in all parameters, while the 25 °C treatment did not significantly differ from the control. Interestingly, exposure to multiple temperature disturbances caused gradually increasing stability in the 35 °C treatment in some parameters, while others parameters showed the opposite, indicating that the choice of parameters can strongly affect the outcome of a study. The acidification event did not lead to stronger changes in community structure, but functional resistance of bacterial production towards acidification in the 35 °C treatments increased. This indicates that functional resistance in response to a novel disturbance can be increased by previous exposure to another disturbance, suggesting similarity in stress tolerance mechanisms for both disturbances. These results highlight the need for understanding function- and disturbance-specific responses, since general responses are likely to be unpredictable.
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| 30. |
- Richardson, Katherine, et al.
(författare)
-
Earth beyond six of nine planetary boundaries
- 2023
-
Ingår i: Science Advances. - 2375-2548. ; 9:37
-
Tidskriftsartikel (refereegranskat)abstract
- This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.
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| 31. |
- Richter, Stephan, et al.
(författare)
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Towards rule-based metabolic databases : a requirement analysis based on KEGG
- 2015
-
Ingår i: International journal of data mining and bioinformatics. - 1748-5673. ; 13:3, s. 289-319
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 32. |
- Saleem, Muhammad, et al.
(författare)
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Diversity of protists and bacteria determines predation performance and stability
- 2013
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Ingår i: The ISME Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370. ; 7:10, s. 1912-1921
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 33. |
- Saleem, Muhammad, et al.
(författare)
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Trophic complexity in aqueous systems : bacterial species richness and protistan predation regulate dissolved organic carbon and dissolved total nitrogen removal
- 2016
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 283:1825
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 34. |
- Singh, Chandrakant, et al.
(författare)
-
Assessing water stress dynamics of the Amazonian rainforest through rootzone storage capacity : A time-series approach
- 2019
-
Ingår i: Geophysical Research Abstracts. - 1029-7006 .- 1607-7962. ; 21
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 35. |
- Singh, Chandrakant
(författare)
-
Forest-savanna transitions: Understanding adaptation and resilience of the tropical forest ecosystems using remote sensing
- 2022
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Climate and deforestation-induced changes in precipitation drive tropical forest-savanna transitions. However, precipitation alone provides a superficial understanding of the underlying mechanism behind these transitions. This is because our knowledge of how vegetation responds to changes in hydroclimate is fragmented. Under a rapidly changing climate, it is increasingly important to understand forest adaptation to predict future forest-savanna transition risks. However, there are two major bottlenecks to achieving this: (i) there is no universal metric that represents forest adaptation, and (ii) at continental scale, empirical evidence to ecosystem response under changing climate is still lacking. This thesis uses remote sensing-derived root zone storage capacity – a novel metric representing the vegetation's capacity to utilise subsoil moisture storage - and above-ground tree cover structure to provide empirical evidence to ecosystems’ response under changing hydroclimate and the influence of hydroclimatic adaptation on the resilience of tropical forests. The results reveal a non-linear relationship between ecosystem’s above-ground structure and subsoil moisture storage capacity. Furthermore, the ecosystem’s capacity to utilise subsoil moisture is much more dynamic and reflective of their transient conditions under changing precipitation than above-ground structure; thereby highlighting its application as an early warning signal. Ignoring this adaptive capacity can undermine forest resilience. The result from this thesis also emphasises the applicability of remote sensing in inferring and assessing ecosystem adaptation under rapid hydroclimatic change and can assist in strengthening management and conservation efforts across the continents.
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| 36. |
- Singh, Chandrakant, et al.
(författare)
-
Hydroclimatic adaptation critical to the resilience of tropical forests
- 2022
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28:9, s. 2930-2939
-
Tidskriftsartikel (refereegranskat)abstract
- Forest and savanna ecosystems naturally exist as alternative stable states. The maximum capacity of these ecosystems to absorb perturbations without transitioning to the other alternative stable state is referred to as ‘resilience’. Previous studies have determined the resilience of terrestrial ecosystems to hydroclimatic changes predominantly based on space-for-time substitution. This substitution assumes that the contemporary spatial frequency distribution of ecosystems’ tree cover structure holds across time. However, this assumption is problematic since ecosystem adaptation over time is ignored. Here we empirically study tropical forests’ stability and hydroclimatic adaptation dynamics by examining remotely sensed tree cover change (ΔTC; aboveground ecosystem structural change) and root zone storage capacity (Sr; buffer capacity towards water-stress) over the last two decades. We find that ecosystems at high (>75%) and low (<10%) tree cover adapt by instigating considerable subsoil investment, and therefore experience limited ΔTC—signifying stability. In contrast, unstable ecosystems at intermediate (30%–60%) tree cover are unable to exploit the same level of adaptation as stable ecosystems, thus showing considerable ΔTC. Ignoring this adaptive mechanism can underestimate the resilience of the forest ecosystems, which we find is largely underestimated in the case of the Congo rainforests. The results from this study emphasise the importance of the ecosystem's temporal dynamics and adaptation in inferring and assessing the risk of forest-savannah transitions under rapid hydroclimatic change.
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| 37. |
- Singh, Chandrakant, et al.
(författare)
-
Landholders leverage over moisture flows and forest resilience in South America
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Moisture originating (i.e., evaporation) from the Amazon basin contributes to the rainfall precipitating over the forest and human-influenced land systems in South America. However, the alarming rate of land use change by landholders in the Amazon – mostly due to agricultural expansion – poses serious threats to regional water cycling. On the one hand, this moisture loss over forests reduces their resilience to future hydroclimatic perturbations (e.g., droughts). Loss of moisture over human-influenced land systems, on the other, threatens agricultural yields. However, the leverage these landholders have over the downwind rainfall is uncertain. Understanding their influence will help us realise the potential of land use change impact on the regional water cycle. In this study, we analyse landholders’ leverage over atmospheric moisture flows and the resilience of forest ecosystems in South America. Using remote-sensing datasets and a process-based moisture tracking model, we track moisture flows from different spatial explicit landholder-dominated regions over to the natural and anthropogenic land systems. We find that of all the moisture originating from small (3.0×103 km3 yr-1), medium (0.6×103 km3 yr-1) and large (4.6×103 km3 yr-1) landholders, nearly 43-56% contributes to the rainfall over the forests. Furthermore, nearly 50% of this evaporated moisture originates from the forests within these landholder-dominated regions. We also find that all landholders equally influence the rainfall precipitating over nearby regions (including their own) and those over the downwind remote actors. Among them, smallholders have a disproportionately larger influence over forests’ rainfall (19-39% more than other landholders’). Despite this, large landholders strongly influence forest resilience in South America, along with their disproportionately larger influence over the agricultural land systems (53-116% more than other landholders’). The results from this study emphasise the need for more stringent forest policies to factor in the influence of deforestation on downwind actors and the need for more effective ecosystem stewardship.
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| 38. |
- Singh, Chandrakant, et al.
(författare)
-
Multi-fold increase in rainforests tipping risk beyond 1.5-2⁰C warming
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Tropical rainforests invest in their root systems to store soil moisture from water-rich periods for use in water-scarce periods. An inadequate root-zone soil moisture storage predisposes or forces these forest ecosystems to transition to a savanna-like state, devoid of their native structure and functions. Yet changes in soil moisture storage and its influence on the rainforest ecosystems under future climate change remain uncertain. Using the empirical understanding of root zone storage capacity, we assess the future state of the rainforests and the forest-savanna transition risk in South America and Africa under four different shared socioeconomic pathway scenarios. We find that by the end of the 21st century, nearly one-third of the total forest area will be influenced by climate change. Furthermore, beyond 1.5-2⁰C warming, ecosystem recovery reduces gradually, whereas the forest-savanna transition risk increases several folds. For Amazon, this risk can grow by about 1.5-6 times compared to its immediate lower warming scenario, whereas for Congo, this risk growth is not substantial (0.7-1.65 times). The insight from this study underscores the urgent need to limit global surface temperatures below the Paris agreement.
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| 39. |
- Singh, Chandrakant, 1992-
(författare)
-
Rooting for forest resilience : Implications of climate and land-use change on the tropical rainforests
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tropical rainforests in the Amazon and Congo River basins and their climate are mutually dependent. Evaporation from these forests help regulate the regional and global water cycle. Furthermore, these rainforests themselves depend on precipitation to sustain their structure and functions. However, the rapid increase in human activities (such as burning fossil fuels and deforestation) has significantly changed the rainforests’ climate. Due to the effect of human-induced perturbations on moisture feedbacks (i.e., precipitation and evaporation patterns), these rainforests risk tipping to a savanna or treeless state.Understanding how these forests respond to climate change will aid in assessing their resilience to water-induced perturbations as well as in anticipating and preparing for potential tipping risks in the future. However, our understanding of how vegetation responds to climate change is fragmented, which limits our capacity to predict these risks. Previous studies have primarily relied on precipitation data to understand these forest-to-savanna transitions. However, ecosystem transition risks are also associated with water-stress, which depends on the vegetation’s capacity to adapt to drier conditions by storing water in its root zone. This thesis investigates the effect of hydroclimatic changes on root zone adaptation and its implications for forest resilience.Paper I uses remote sensing data to analyse water-stress and drought coping strategies across the rainforest-savanna transects. Paper II uses the root zone storage capacity to quantify the resilience of forest ecosystems. Using the empirical understanding of root zone forest dynamics and hydroclimatic estimates from Earth System Models, Paper III projects future forest transitions and estimates tipping risks by the end of the 21st century under four different shared socio-economic pathways. Paper IV uses atmospheric moisture tracking data to investigate the leverage landholders in South America have over precipitation and the resilience of forest ecosystems. Papers I and II reveal the non-linear relationship between the ecosystem’s above-ground structure and root zone storage capacity. These studies indicate that, under hydroclimatic changes, the ecosystem’s root zone storage capacity is much more dynamic than its above-ground forest structure and is more representative of the ecosystem’s transient state than precipitation. Ignoring this root zone adaptive capacity can underestimate forest resilience, primarily observed in the Congo rainforest. Paper III projects that the risk of forest-savanna transition will increase with climate change severity, most prominently observed in the Amazon rainforest. Paper IV finds that all landholders have equal leverage over the moisture precipitating locally and over farther-downwind land systems. According to this study, smallholders have a disproportionately larger influence over forest rainfall. However, large landholders have a larger influence on forest resilience as well as over the moisture precipitating on croplands and pastures. These results warrant the need for policies to factor in the impact of deforestation on downwind actors and promote effective ecosystem stewardship. The insights from this thesis highlight the importance of understanding and assessing ecosystem dynamics under a rapidly changing climate for strengthening management and conservation efforts across the globe.
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| 40. |
- Singh, Chandrakant, et al.
(författare)
-
Rootzone storage capacity reveals drought coping strategies along rainforest-savanna transitions
- 2020
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 15:12
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Climate change and deforestation have increased the risk of drought-induced forest-to-savanna transitions across the tropics and subtropics. However, the present understanding of forest-savanna transitions is generally focused on the influence of rainfall and fire regime changes, but does not take into account the adaptability of vegetation to droughts by utilizing subsoil moisture in a quantifiable metric. Using rootzone storage capacity (Sr), which is a novel metric to represent the vegetation's ability to utilize subsoil moisture storage and tree cover (TC), we analyze and quantify the occurrence of these forest-savanna transitions along transects in South America and Africa. We found forest-savanna transition thresholds to occur around a Sr of 550–750 mm for South America and 400–600 mm for Africa in the range of 30%–40% TC. Analysis of empirical and statistical patterns allowed us to classify the ecosystem's adaptability to droughts into four classes of drought coping strategies: lowly water-stressed forest (shallow roots, high TC), moderately water-stressed forest (investing in Sr, high TC), highly water-stressed forest (trade-off between investments in Sr and TC) and savanna-grassland regime (competitive rooting strategy, low TC). The insights from this study are useful for improved understanding of tropical eco-hydrological adaptation, drought coping strategies, and forest ecosystem regime shifts under future climate change.
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| 41. |
- Staal, Arie, et al.
(författare)
-
Feedback between drought and deforestation in the Amazon
- 2020
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 15:4
-
Tidskriftsartikel (refereegranskat)abstract
- Deforestation and drought are among the greatest environmental pressures on the Amazon rainforest, possibly destabilizing the forest-climate system. Deforestation in the Amazon reduces rainfall regionally, while this deforestation itself has been reported to be facilitated by droughts. Here we quantify the interactions between drought and deforestation spatially across the Amazon during the early 21st century. First, we relate observed fluctuations in deforestation rates to dry-season intensity; second, we determine the effect of conversion of forest to cropland on evapotranspiration; and third, we simulate the subsequent downwind reductions in rainfall due to decreased atmospheric water input. We find large variability in the response of deforestation to dry-season intensity, with a significant but small average increase in deforestation rates with a more intense dry season: with every mm of water deficit, deforestation tends to increase by 0.13% per year. Deforestation, in turn, has caused an estimated 4% of the recent observed drying, with the south-western part of the Amazon being most strongly affected. Combining both effects, we quantify a reinforcing drought-deforestation feedback that is currently small, but becomes gradually stronger with cumulative deforestation. Our results suggest that global climate change, not deforestation, is the main driver of recent drying in the Amazon. However, a feedback between drought and deforestation implies that increases in either of them will impede efforts to curb both.
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| 42. |
- Staal, Arie, et al.
(författare)
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Hysteresis of tropical forests in the 21st century
- 2020
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Tropical forests modify the conditions they depend on through feedbacks at different spatial scales. These feedbacks shape the hysteresis (history-dependence) of tropical forests, thus controlling their resilience to deforestation and response to climate change. Here, we determine the emergent hysteresis from local-scale tipping points and regional-scale forest-rainfall feedbacks across the tropics under the recent climate and a severe climate-change scenario. By integrating remote sensing, a global hydrological model, and detailed atmospheric moisture tracking simulations, we find that forest-rainfall feedback expands the geographic range of possible forest distributions, especially in the Amazon. The Amazon forest could partially recover from complete deforestation, but may lose that resilience later this century. The Congo forest currently lacks resilience, but is predicted to gain it under climate change, whereas forests in Australasia are resilient under both current and future climates. Our results show how tropical forests shape their own distributions and create the climatic conditions that enable them. Tropical rainforests partly create their own climatic conditions by promoting precipitation, therefore rainforest losses may trigger dramatic shifts. Here the authors combine remote sensing, hydrological modelling, and atmospheric moisture tracking simulations to assess forest-rainfall feedbacks in three major tropical rainforest regions on Earth and simulate potential changes under a severe climate change scenario.
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| 43. |
- Steffen, Will, et al.
(författare)
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Planetary boundaries : Guiding human development on a changing planet
- 2015
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 347:6223
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 44. |
- Steffen, Will, et al.
(författare)
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Trajectories of the Earth System in the Anthropocene
- 2018
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 115:33, s. 8252-8259
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 45. |
- Stolpovsky, Konstantin, et al.
(författare)
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Influence of dormancy on microbial competition under intermittent substrate supply : insights from model simulations
- 2016
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 92:6
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 46. |
- Tischer, Karolin, et al.
(författare)
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Microbial communities along biogeochemical gradients in a hydrocarbon-contaminated aquifer
- 2013
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Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 15:9, s. 2603-2615
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 47. |
- Tobian, Arne, 1992-, et al.
(författare)
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Climate change critically affects the status of the land-system change planetary boundary
- 2024
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Ingår i: Environmental Research Letters. - 1748-9326. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten phase 6 of the Coupled Model Intercomparison Project models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth's major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (>450 ppm) leads to critical transgression of the latter, with greater severity the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today's boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the planetary boundaries framework.
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| 48. |
- Tobian, Arne, 1992-
(författare)
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Entering the dynamic risk space : Assessing planetary boundary interactions through process-based quantifications
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The planetary boundaries framework is an effort to define a safe operating space for humanity. Its rationale is that sustainable development needs to be achieved in ways that safeguard the stability of the Earth system on which human prosperity relies. However, very few studies explicitly examine the interactions of the Earth system processes that underlie individual boundaries.My overarching research question is: how can continued anthropogenic climate change affect the geospatially resolvable land and water planetary boundaries, and what are the implications for human livelihood? For most of my analysis, I use the LPJmL dynamic global vegetation model because it contains suitable process representations that provide a dynamic and adaptive Earth system perspective for my investigation of key planetary boundary interactions of the climate, land, water and ecosystem nexus.Paper I emphasizes the importance of green water dynamics (that is terrestrial precipitation, evapotranspiration and plant-available soil moisture) for ecosystem resilience and human well-being. The underlying analysis suggests that the current status of the proposed planetary boundary for green water is already transgressed. Paper II reveals long-term spatiotemporal dynamics of planetary boundary interactions as breaching the climate change boundary critically affects the world’s major forest biomes. Notably, the most extreme climate change scenarios led to the emergence of a southern boreal dieback in the simulations. Tropical forests further show a shift from evergreen to deciduous rainforest, an important process which is not captured by the definition of the land-system change boundary. Maintaining climate change at the planetary boundary co-stabilizes the land-system change boundary. Paper III extends the biophysical understanding of planetary boundary interactions by discussing their impact on human livelihood and the attainment of the Sustainable Development Goals. Future climate change causes increases in dry anomalies of green water in ~30% of the global land area by the end of the century. As of today (here referring to 2015), nearly a quarter of the world population and ~28% of global harvest would be affected. The dynamic risk space terminology is established to fill the conceptual gap in the analysis of planetary boundary interactions. Paper IV highlights how planetary stability constitutes the non-negotiable fundament for human development and argues why the Sustainable Development Goals have to be aligned with the planetary boundaries framework and which perils might arise from their interactions. Paper V presents the land-system change reallocation tool algorithm which allows for a scenario-driven rearrangement of human land-use to meet varying transgression levels of the land-system change boundary. My results of Paper I-V advance the understanding of interactions in the planetary boundaries framework. Moreover, my analysis in a process-based and validated modeling environment gives spatiotemporal detail of the processes at play that exceeds the potential of previously used conceptual models. My work fills a crucial gap in the operationalization of the planetary boundary framework by providing insights into how and where different policy options produce positive or negative outcomes across boundaries. The holistic understanding I present is a prerequisite for any application of the planetary boundaries framework that focuses on future conditions.
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| 49. |
- Wang-Erlandsson, Lan, et al.
(författare)
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A planetary boundary for green water
- 2022
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Ingår i: Nature Reviews Earth & Environment. - : Springer Science and Business Media LLC. - 2662-138X. ; 3:6, s. 380-392
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Tidskriftsartikel (refereegranskat)abstract
- Green water — terrestrial precipitation, evaporation and soil moisture — is fundamental to Earth system dynamics and is now extensively perturbed by human pressures at continental to planetary scales. However, green water lacks explicit consideration in the existing planetary boundaries framework that demarcates a global safe operating space for humanity. In this Perspective, we propose a green water planetary boundary and estimate its current status. The green water planetary boundary can be represented by the percentage of ice-free land area on which root-zone soil moisture deviates from Holocene variability for any month of the year. Provisional estimates of departures from Holocene-like conditions, alongside evidence of widespread deterioration in Earth system functioning, indicate that the green water planetary boundary is already transgressed. Moving forward, research needs to address and account for the role of root-zone soil moisture for Earth system resilience in view of ecohydrological, hydroclimatic and sociohydrological interactions.
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| 50. |
- Wang-Erlandsson, Lan, et al.
(författare)
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Remote land use impacts on river flows through atmospheric teleconnections
- 2018
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Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 22:8, s. 4311-4328
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Tidskriftsartikel (refereegranskat)abstract
- 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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