| 1. |
- Åhlén, Imenne, 1991-
(författare)
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Ecosystem services of wetlands and wetlandscapes under hydro-climatic change : Impacts of water flow and inundation patterns
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wetlands provide ecosystem services valuable for human society and are therefore often considered as nature based solution to different environmental problems. However, with centuries of wetland degradation due to anthropogenic pressures, such as agricultural expansion and forest industry, as well as pressures from climate change, there are large challenges for sustainable wetland management. Thus, for wetland protection and restoration practices to be successful, a deepened understanding on the actual mechanisms controlling wetland functions is required. Understanding how wetlands are connected, with and influenced, by their surrounding environment is also needed. Although most pressures experienced by wetlands operate on scales beyond the individual wetland scale, relatively few studies have thus far addressed large-scale functions and ecosystem service provision from hydrologically interconnected wetlands at the scale of wetlandscapes (i.e., the wetlands’ aggregated hydrological catchments in the landscape). The aim of this thesis is to investigate ecosystem service delivery from wetlands and wetlandscapes under hydro-climatic changes, considering 25 different wetlandscapes located in four different climate zones of the world. The thesis also systematically quantifies ecohydrological characteristics important for ecosystem service delivery and biodiversity support of wetlands and wetlandscapes in the Norrström Drainage basin located near Stockholm, Sweden. Conducted hydro-climatic analyses showed that impacts of climate change on wetlandscapes cannot be fully understood from average changes in climatic variables of the climate zones within which the wetlandscapes are located. This may be due to the fact that wetlands are not randomly and evenly distributed within climate zones, but may be located in areas subject to stronger climatic changes than regional means. In addition, anthropogenic pressures were on average shown to have higher impacts on runoff in wetlandscapes in comparison to climate change. The pressures however showed relatively large variability between different wetlandscapes, which needs to be considered in mitigation strategies against wetland degradation and deterioration. Similarly, regarding wetlandscape ecohydrological characteristics, results indicated that there are variability between wetlandscapes of different sizes, where larger wetlandscapes showed features that can support ecosystem services to larger degree than small wetlandscapes. Large spatial variability in wetland ecohydrological characteristics was also seen within a wetlandscape. For instance, water storage dynamics and buffering capacity varied depending on the position of the wetland in the landscape. These differences in hydrological conditions were shown to result in different inundation dynamics between wetlands, which for instance also showed to impact insect community composition.Overall, this thesis shows that assessments of wetland ecosystem services need to be addressed using a wetlandscape approach, combined with actual on site hydrological measurements. The approach used in this thesis could help decrease uncertainties related to the impacts of hydro-climatic changes and anthropogenic pressures on wetlands and wetlandscapes, supporting location-specific wetland management strategies related to creation, restoration and sustainable use of wetlands and their ecosystems.
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| 2. |
- Levi, Lea, 1984-
(författare)
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Data-driven analysis of water and nutrient flows: Case of the Sava River Catchment and comparison with other regions
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A growing human population and demands for food, freshwater and energy are causing extensive changes in the water and biogeochemical cycles of river catchments around the world. Addressing and investigating such changes is particularly important for transboundary river catchments, where they impose additional risk to a region’s stability. This thesis investigates and develops data-driven methodologies for detecting hydro-climatic and nutrient load changes and their drivers with limited available data and on different catchment scales. As a specific case study, we analyze the Sava River Catchment (SRC) and compare its results with other world regions. A past–present to future evaluation of hydro-climatic data is done on the basis of a water balance approach including analysis of historic developments of land use and hydropower development data and projections of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) output. Using observed water discharge and nutrient concentration data, we propose a novel conceptual model for estimating and spatially resolving total nitrogen (TN) and total phosphorus (TP) input and delivery-retention properties for a river catchment and its nested subcatchments, as well as detection of nutrient hotspots. The thesis identifies hydroclimatic change signals of hydropower-related drivers and finds consistency with other world regions. The proposed nutrient screening methodology provides a good distinction between human-related nutrient inputs and landscape-related transport influences on nutrient loading at subcatchment to catchment scale. A cross-regional comparison of the SRC data with the Baltic region shows similarity between nutrient-relevant indicators and driving socio-economic and hydro-climatic conditions. The study highlights a number of complexities with regard to CMIP5 model representation of water fluxes. The large intermodel range of CMIP5 future projections of fluxes calls for caution when using individual model results for assessing ongoing and future water and nutrient changes.
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| 3. |
- Sjöberg, Ylva, 1982-
(författare)
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Linking water and permafrost dynamics
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The extent and dynamics of permafrost are tightly linked to the distribution and movement of water in arctic landscapes. As the Arctic warms more rapidly than the global average, profound changes are expected in both permafrost and hydrology; however, much is still not known about the interactions between these two systems. The aim of this thesis is to provide new knowledge on the links between permafrost and hydrology under varying environmental conditions and across different scales. The objectives are to (i) determine how permafrost distributions and patterns in morphology are linked to hydrology, (ii) determine how groundwater flow influences ground temperature dynamics in permafrost landscapes, and (iii) explore the mechanisms that link permafrost to groundwater and streamflow dynamics. A range of methods have been applied within the four studies (papers I-IV) comprising the thesis: geophysical (ground penetrating radar and electrical resistivity tomography) and GIS techniques for mapping and analyzing permafrost distributions and related morphology; numerical modeling of coupled heat and water fluxes for mechanistic understanding permafrost-hydrological links; and statistical analyses for detecting trends in streamflow associated with permafrost thaw. Combining these various methods here allows for, and may be considered a prerequisite for, novel insights to processes. The thesis also presents statistical analyses of field observations of ground temperatures, ground- and surface water levels, as well as lake and shore morphological variables. Discontinuous permafrost peatlands are heterogeneous environments regarding permafrost distributions and thickness which is manifested in surface systems such as lake geometries. In these environments, lateral groundwater fluxes, which are not considered in most permafrost models, can significantly influence ground temperature dynamics, especially during high groundwater gradient conditions. River discharge data provide a potential for monitoring catchment-scale changes in permafrost, as the magnitude and seasonality of groundwater fluxes feeding into streams are affected by the distribution of permafrost. This thesis highlights the need to understand water and permafrost as an integrated system with potential internal feedback processes. For example, permafrost thaw can lead to increases in groundwater discharge which in turn can lead to increased heat transfer through the ground, resulting in further acceleration of permafrost thaw rates.
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| 4. |
- Engström, Rebecka Ericsdotter, 1984-
(författare)
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Exploring cross-resource impacts of urban sustainability measures : an urban climate-land-energy-water nexus analysis
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In an increasingly urban world, cities' global resource uses grow. Two fundamental resources for making cities liveable are water and energy. These resources are also closely interlinked – systems that convert and deliver energy to cities require water, and urban water systems use energy. In addition, these two resource systems affect and are affected by land use and climate change. This ‘nexus’ between climate, land use, energy and water (CLEW) systems has been extensively studied in the past decade, mainly with a focus on national and transboundary CLEW systems. This doctoral thesis develops the CLEW nexus research from an urban perspective.Two quantitative analyses examine how different types of sustainability measures in cities affect intended and unintended CLEW systems. First, the CLEW impacts of a set of sustainability measures in New York City are assessed - from water conservation to emission reductions. Results show that every measure affects (to varying degrees) all studied sustainability dimensions - water, energy and climate - and that the impacts can be quantified through a reference-resource-to-service-system (RRSS).The second quantitative study focuses on how CLEW impacts from a city's sustainability efforts spread beyond local and international borders. It investigates how global water and land use are affected in alternative scenarios to achieve climate neutrality in 2030 in the town of Oskarshamn, Sweden, using an energy systems simulation model. The study finds that both the magnitude and the geographical distribution of land and water requirements vary between scenarios. A strategy to achieve climate neutrality that invests in electrification leads to increased national water use, while a strategy that relies on biofuels has a greater impact on water and land use internationally. When results are translated to interactions between the UN's sustainable development goals (SDGs), they reveal that SDG synergies and trade-offs are 'strategy-dependent': different options for achieving SDGs on energy, sustainable cities and climate action have varying consequences for the advancement of SDGs on sustainable water, food production and biodiversity.To shed light on how data challenges affect quantitative urban nexus studies, uncertainty assessments of selected thesis’ results are conducted and complemented with a thematic analysis of a set of recently published urban nexus papers. Together, they indicate that analytical choices, uncertainties in results and - as a consequence - research foci are influenced by data limitations in both this thesis and in other urban nexus studies.Lastly, the finding from the Oskarshamn analysis – that SDG interactions are strategy-dependent – is deliberated with experts within sustainability sciences and SDG interaction research. From this, a research agenda is proposed with measures to make SDG 'spillovers' visible in local level decision-making.Taken together, the thesis contributes to filling several knowledge gaps on how urban sustainability measures within the CLEW systems interact within and beyond city limits, and proposes analytical approaches to quantify these interactions. It further points out how current data challenges constrain quantitative urban nexus analyses and highlights research needs to improve data management as well as other key efforts to enable consideration of nexus interactions, including SDG 'spillovers', in cities' sustainability work.
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| 5. |
- Finné, Martin, 1981-
(författare)
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Climate in the eastern Mediterranean during the Holocene and beyond – A Peloponnesian perspective
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contributes increased knowledge about climate variability during the late Quaternary in the eastern Mediterranean. Results from a paleoclimate review reveal that regional wetter conditions from 6000 to 5400 years BP were replaced by a less wet period from 5400 to 4600 years BP and to fully arid conditions around 4600 years BP. The data available, however, show that there is not enough evidence to support the notion of a widespread climate event with rapidly drying conditions in the region around 4200 years ago. The review further highlights the lack of paleoclimate data from the archaeologically rich Peloponnese Peninsula. This gap is addressed in this thesis by the provision of new paleoclimate records from the Peloponnese. One stalagmite from Kapsia Cave and two stalagmites from Glyfada Cave were dated and analyzed for stable oxygen (δ18O) and carbon (δ13C) isotopes. The Glyfada record covers a period from ~78 ka to ~37 ka and shows that the climate in this region responded rapidly to changes in temperatures over Greenland. During Greenland stadial (interstadial) conditions colder (warmer) and drier (wetter) conditions are reflected by depleted (enriched) δ13C-values in the speleothems. The Kapsia record covers a period from ~2900 to ~1100 years BP. A comparison between the modern stalagmite top isotopes and meteorological data shows that a main control on stalagmite δ18O is wet season precipitation amount. The δ18O record from Kapsia indicates cyclical humidity changes of close to 500 years, with rapid shifts toward wetter conditions followed by slowly developing aridity. Superimposed on this signal is a centennial signal of precipitation variability. A second speleothem from Kapsia with multiple horizons of fine sediments from past flood events intercalated with the calcite is used to develop a new, quick and non-destructive method for tracing flood events in speleothems by analyzing a thick section with an XRF core scanner.
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| 6. |
- Darracq, Amelie
(författare)
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Long-term development, modeling and management of nutrient loading to inland and coastal waters
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental and water system protection and restoration require accurate knowledge and quantification of waterborne pollutant transport, retention-release and transformation processes taking place in the subsurface, river, lake and sea water systems, and at the interfaces between these systems. This thesis investigates the importance of spatial model resolution for such quantification and the possible long-term nutrient load development under different human perturbations and nutrient source management scenarios in the Swedish Norrström drainage basin, based on simulations with the GIS-based dynamic nutrient transport-attenuation model POLFLOW. The results indicate substantial nutrient load contributions from the subsurface water system (soil water and groundwater) to surface waters, which may largely control present and future nutrient mass loads from drainage basins to downstream inland and coastal waters. This role of the subsurface water system needs to be acknowledged, in conjunction with the effects of expected climate change and population and lifestyle developments, for achieving successful and sustained decreases in nutrient loading to inland and coastal waters. The results point also towards a need for downstream nutrient load control and abatement measures, to complement nutrient source reduction programs. The results further indicate the importance of the chosen spatial model resolution and account for subgrid variability for the accuracy of the necessary coupled transport and attenuation modeling of nutrient spreading in, and export from, river networks to coastal systems. Failure to correctly conceptualize and accurately account for the physical transport processes and their subgrid variability in this modeling may also yield systematic misinterpretation of the biogeochemical processes and process rates. Further, this may have important practical implications for the necessary abatement effectiveness and efficiency of nutrient and other waterborne pollutant loading to inland and coastal waters worldwide.
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| 7. |
- Hannerz, Fredrik, 1977-
(författare)
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Making water information relevant on local to global scale – the role of Information Systems for Integrated Water Management
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.
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| 8. |
- Jantze, Elin, 1983-
(författare)
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Waterborne Carbon in Northern Streams : Controls on dissolved carbon transport across sub-arctic Scandinavia
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Waterborne carbon (C) forms an active and significant part of the global C cycle, which is important in theArctic where greater temperature increases and variability are anticipated relative to the rest of the globe withpotential implications for the C cycle. Understanding and quantification of the current processes governing themovement of C by connecting terrestrial and marine systems is necessary to better estimate future changes ofwaterborne C. This thesis investigates how the sub-arctic landscape influences the waterborne carbon exportby combining data-driven and modeling methods across spatial and temporal scales. First, a study of the stateof total organic carbon monitoring in northern Scandinavia was carried out using national-scale monitoringdata and detailed data from scientific literature. This study, which highlights the consistency in land cover andhydroclimatic controls on waterborne C across northern Scandinavia, was combined with three more detailedstudies leveraging field measurements and modeling. These focused on the Abisko region to provide insightto processes and mechanisms across scales. The thesis highlights that the governing transport mechanismsof dissolved organic and inorganic carbon (DOC and DIC respectively) are fundamentally different due todifferences in release rates associated with the nature of their terrestrial sources (geogenic and organic matterrespectively). As such, the DIC mass flux exhibits a high flow-dependence whereas DOC is relatively flowindependent.Furthermore, these investigations identified significant relationships between waterborne C andbiogeophysical as well as hydroclimatic variables across large to small spatial scales. This thesis demonstratesthat both surface and sub-surface hydrological processes (such as flow pathway distributions) in combinationwith distributions of C sources and associated release rates are prerequisite for understanding waterborne Cdynamics in northern streams.
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| 9. |
- Johansson, Emma, 1979-
(författare)
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The influence of climate and permafrost on catchment hydrology
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The cycling of water in the landscape is influenced by climate change on different time scales and in different directions regarding warming or cooling trends. Along with a changing climate, also the landscape and subsurface conditions, such as permafrost extent, may change in a long-term perspective. Permafrost and hydrology are intimately connected but the interactions between them are poorly understood, and the hydrological response to climate change is complex. The first part of this thesis investigates the effects of different drivers of future changes in hydrological flow and water storage components in the present day temperate Forsmark catchment in Sweden. The role of taliks and their influence on the exchange of deep and shallow groundwater in permafrost environments are also studied. This is done by a simulation sequence where the site is exposed to the landscape, climate and permafrost changes expected from site-specific numerical modeling. In the second part of this thesis, present day periglacial hydrological processes are studied in the Two Boat Lake catchment in western Greenland by field and model investigations of the site. The presence of a through talik below the Two Boat Lake, and data from a deep bedrock borehole into the talik, enable studies of the hydrological interactions between the lake and the talik. The spatial and temporal variability of the different water balance components of the catchment are quantified and the interactions between the surface water and the supra- and sub-permafrost groundwater are analyzed.The results show that the investigated changes in climate and permafrost influence hydrology more than the investigated landscape changes. Under permafrost conditions, the general direction of the exchange between deep and shallow groundwater may change relative to unfrozen conditions. The simulation studies of Forsmark show that the relative topography between taliks governs the recharging and discharging conditions, which is consistent with results from Two Boat Lake. The lake is located at high altitude relative to other taliks and hydraulic measurements indicate recharging conditions. The talik recharge is small compared to other water balance components and does not influence the lake level, which instead is found to be controlled by evapotranspiration and water inflow from the active layer. This is concluded from numerical simulations that take into account and combine evapotranspiration with other surface and subsurface hydrological processes. This thesis highlights the need to integrate surface and subsurface process modelling in order to quantitatively understand and represent the dynamics and complexity of hydrological interactions in periglacial catchments.
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| 10. |
- Kåresdotter, Elisie, 1987-
(författare)
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Water in a Changing World : Unraveling the Complexities of Conflict and Cooperation
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Water is a crucial resource that can unite or divide nations, but throughout history, people have generally cooperated to solve water-related issues. However, as freshwater scarcity intensifies due to climate shifts and escalating human demands, it is critical to identify water-related conflicts and cooperation dynamics. For instance, changes in water patterns, including floods, droughts, and dam construction to manage varying precipitation, could lead to increased competition and conflict over water resources. Effective water management and collaboration could help resolve these issues and foster peaceful water governance. The main aim of this thesis is to examine the connections between how humans, the climate, and changes in water have affected cooperation and conflicts over water. This research involves investigating the interactions between changes in freshwater availability, water-related events such as conflicts and cooperation, and changes in human activities and climate. The focus is mainly on global and regional large-scale levels, and the work comprises four parts: (i) a scoping review of previous scientific literature to identify important conflict factors and research gaps; (ii) hydrological modeling to determine the direction and magnitude of hydroclimatic change relating to human activities; (iii) creation of an updated water-related conflict and cooperation database and analysis of current trends; and (iv) analyses of how socio-economic and climatic factors affect water events and cooperation mechanisms behind successful conflict mitigation.The combined results from the four parts reveal that governance, policy, and climate change are important conflict factors worldwide. Agriculture emerges as particularly important in Africa and Asia, but there are regional variations in the importance of different conflict factors to these water conflicts. A significant research gap emerges for regions outside Africa and parts of Asia. This is problematic since influencing conflict factors appear to differ between regions. Scrutiny of the updated water event database showed that water events are increasing in frequency in most regions of the world but that cooperation is decreasing in parts of Africa, the Middle East, and South America. Changes in water events appear to be largely driven by climate change in Africa and by human activities in Asia. Changes in population density, urban-rural distribution, and precipitation have only small effects on conflict and cooperation outcomes, while economic factors such as gross domestic product (GDP) and export dependency have significant effects.The thesis reveals the interplay between human activities, climate change, and water governance, shedding light on the global dynamics that shape water conflicts and cooperation. The results underscore the critical need for adaptive water management strategies informed by comprehensive, region-specific insights. Future studies should, therefore, seek to develop innovative governance frameworks, predictive models for conflict prevention, and resilient water-sharing agreements that can withstand the challenges posed by global environmental changes. Such work will require an integrated approach, combining socio-economic, hydrological, and climate perspectives, to foster sustainable water management and peacebuilding efforts in an era of increasing uncertainty.
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