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  • 251.
    Ballarotta, Maxime
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Döös, Kristofer
    Stockholm University, Faculty of Science, Department of Meteorology .
    Lundberg, Peter
    Stockholm University, Faculty of Science, Department of Meteorology .
    Brodeau, Laurent
    Stockholm University, Faculty of Science, Department of Meteorology .
    Brandefelt, Jenny
    A Last Glacial Maximum World-Ocean simulation at eddy-permitting resolution – Part 2: Confronting the paleo-proxy data2013In: Climate of the Past Discussions, ISSN 1814-9340, E-ISSN 1814-9359, Vol. 9, p. 329-350Article in journal (Refereed)
    Abstract [en]

    Previous investigations concerning the design of an eddy-permitting LGM oceanic sim- ulation are here extended with focus on whether this type of simulation is capable of improving the numerical results with regard to the available paleo-proxy reconstructions. Consequently, an eddy-permitting and two coarse-grid simulations of the same LGM period are confronted with a dataset from the Multiproxy Approach for the Recon- struction of the Glacial Ocean Sea Surface Temperatures (MARGO SSTs) and a num- ber of sea-ice reconstructions. From a statistical analysis it was found that the eddy- permitting simulation does not significantly improve the SST representation with regard to the paleo-reconstructions. The western boundary currents are better resolved in the high-resolution experiment than in the coarse simulations, but, although these more detailed SST structures yield a locally improved consistency between modelled pre- dictions and proxies, they do not contribute significantly to the global statistical score. As in the majority of the PMIP2 simulations, the modelled sea-ice conditions are still inconsistent with the paleo-reconstructions, probably due to the choice of the model equilibrium. 

  • 252.
    Ballarotta, Maxime
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Döös, Kristofer
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nycander, Jonas
    Stockholm University, Faculty of Science, Department of Meteorology .
    Brodeau, Laurent
    Stockholm University, Faculty of Science, Department of Meteorology .
    Falahat, Saeed
    Stockholm University, Faculty of Science, Department of Meteorology .
    The vigorous large-scale ocean circulations during the Last Glacial MaximumManuscript (preprint) (Other academic)
    Abstract [en]

    The representation of the ocean thermohaline circulation (THC) under glacial and interglacial climate conditions is investigated using a new global thermohaline stream function. Consequently, the interglacial and glacial THCs are compared from two experiments based on an ocean general circulation model forced at the surface by conditions representing the present-day and the period of the Last Glacial Maximum (LGM, ≈ 21kyr ago). It is shown  that the LGM THC is amplified by the salinity/density contrast between the Atlantic and the Pacific basins, as well as in the abyss due to larger salinity gradients. Even though the circuit along the Conveyor Belt loop is not drastically changed, the water mass transformations can regionally differ between the two periods. Additionally, the LGM Conveyor Belt Cell is more  isolated from the abyss and its turnover time is between two and three times shorter than in the present-day simulation, suggesting vigorous large-scale circulation. 

  • 253.
    Ballarotta, Maxime
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Falahat, Saeed
    Stockholm University, Faculty of Science, Department of Meteorology .
    Brodeau, Laurent
    Stockholm University, Faculty of Science, Department of Meteorology .
    Döös, Kristofer
    Stockholm University, Faculty of Science, Department of Meteorology .
    On the glacial and interglacial thermohaline circulation and the associated transports of heat and freshwater2014In: Ocean Science, ISSN 1812-0784, E-ISSN 1812-0792, Vol. 10, no 6, p. 907-921Article in journal (Refereed)
    Abstract [en]

    The thermohaline circulation (THC) and the oceanic heat and freshwater transports are essential for understanding the global climate system. Streamfunctions are widely used in oceanography to represent the THC and estimate the transport of heat and freshwater. In the present study, the regional and global changes of the THC, the transports of heat and freshwater and the timescale of the circulation between the Last Glacial Maximum (LGM, ≈ 21 kyr ago) and the present-day climate are explored using an Ocean General Circulation Model and streamfunctions projected in various coordinate systems. We found that the LGM tropical circulation is about 10% stronger than under modern conditions due to stronger wind stress. Consequently, the maximum tropical transport of heat is about 20% larger during the LGM. In the North Atlantic basin, the large sea-ice extent during the LGM constrains the Gulf Stream to propagate in a more zonal direction, reducing the transport of heat towards high latitudes by almost 50% and reorganising the freshwater transport. The strength of the Atlantic Meridional Overturning Circulation depends strongly on the coordinate system. It varies between 9 and 16 Sv during the LGM, and between 12 to 19 Sv for the present day. Similar to paleo-proxy reconstructions, a large intrusion of saline Antarctic Bottom Water takes place into the Northern Hemisphere basins and squeezes most of the Conveyor Belt circulation into a shallower part of the ocean. These different haline regimes between the glacial and interglacial period are illustrated by the streamfunctions in latitude–salinity coordinates and thermohaline coordinates. From these diagnostics, we found that the LGM Conveyor Belt circulation is driven by an enhanced salinity contrast between the Atlantic and the Pacific basin. The LGM abyssal circulation lifts and makes the Conveyor Belt cell deviate from the abyssal region, resulting in a ventilated upper layer above a deep stagnant layer, and an Atlantic circulation more isolated from the Pacific. An estimate of the timescale of the circulation reveals a sluggish abyssal circulation during the LGM, and a Conveyor Belt circulation that is more vigorous due to the combination of a stronger wind stress and a shortened circulation route.

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  • 254.
    Ballarotta, Maxime
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Laurent, Brodeau
    Stockholm University, Faculty of Science, Department of Meteorology .
    Jenny, Brandefelt
    Lundberg, Peter
    Stockholm University, Faculty of Science, Department of Meteorology .
    Döös, Kristofer
    Stockholm University, Faculty of Science, Department of Meteorology .
    Last Glacial Maximum world ocean simulations at eddy-permitting and coarse resolutions: do eddies contribute to a better consistency between models and palaeoproxies?2013In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 9, no 6, p. 2669-2686Article in journal (Refereed)
    Abstract [en]

    Most state-of-the-art climate models include a coarsely resolved oceanic component, which hardly captures detailed dynamics, whereas eddy-permitting and eddy-resolving simulations are developed to reproduce the observed ocean. In this study, an eddy-permitting and a coarse resolution numerical experiment are conducted to simulate the global ocean state for the period of the Last Glacial Maximum (LGM, ~26 500 to 19 000 yr ago) and to investigate the improvements due to taking into account the smaller spatial scales. The ocean state from each simulation is confronted with a data set from the Multiproxy Approach for the Reconstruction of the Glacial Ocean (MARGO) sea surface temperatures (SSTs), some reconstructions of the palaeo-circulations and a number of sea-ice reconstructions. The western boundary currents and the Southern Ocean dynamics are better resolved in the high-resolution experiment than in the coarse simulation, but, although these more detailed SST structures yield a locally improved consistency between model predictions and proxies, they do not contribute sig- nificantly to the global statistical score. The SSTs in the tropical coastal upwelling zones are also not significantly improved by the eddy-permitting regime. The models perform in the mid-latitudes but as in the majority of the Paleo- climate Modelling Intercomparison Project simulations, the modelled sea-ice conditions are inconsistent with the palaeo-reconstructions. The effects of observation locations on the comparison between observed and simulated SST suggest that more sediment cores may be required to draw reliable conclusions about the improvements introduced by the high resolution model for reproducing the global SSTs. One has to be careful with the interpretation of the deep ocean state which has not reached statistical equilibrium in our simula-tions. However, the results indicate that the meridional overturning circulations are different between the two regimes, suggesting that the model parametrizations might also play a key role for simulating past climate states. 

  • 255.
    Balmonte, John Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Univ N Carolina, Dept Marine Sci, Chapel Hill, NC 27515 USA.
    Hasler-Sheetal, Harald
    Univ Southern Denmark, Dept Biol, Odense, Denmark.
    Glud, Ronnie N.
    Univ Southern Denmark, Dept Biol, Odense, Denmark;Tokyo Univ Marine Sci & Technol, Dept Ocean & Environm Sci, Tokyo, Japan.
    Andersen, Thorbjörn J.
    Univ Copenhagen, Dept Geosci & Nat Resources Management, Sect Geog, Copenhagen, Denmark.
    Sejr, Mikael K.
    Aarhus Univ, Arctic Res Ctr, Aarhus, Denmark;Aarhus Univ, Dept Biosci, Silkeborg, Denmark.
    Middelboe, Mathias
    Univ Copenhagen, Marine Biol Sect, Helsingor, Denmark.
    Teske, Andreas
    Univ N Carolina, Dept Marine Sci, Chapel Hill, NC 27515 USA.
    Arnosti, Carol
    Univ N Carolina, Dept Marine Sci, Chapel Hill, NC 27515 USA.
    Sharp contrasts between freshwater and marine microbial enzymatic capabilities, community composition, and DOM pools in a NE Greenland fjord2020In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 65, no 1, p. 77-95Article in journal (Refereed)
    Abstract [en]

    Increasing glacial discharge can lower salinity and alter organic matter (OM) supply in fjords, but assessing the biogeochemical effects of enhanced freshwater fluxes requires understanding of microbial interactions with OM across salinity gradients. Here, we examined microbial enzymatic capabilities-in bulk waters (nonsize-fractionated) and on particles (>= 1.6 mu m)-to hydrolyze common OM constituents (peptides, glucose, polysaccharides) along a freshwater-marine continuum within Tyrolerfjord-Young Sound. Bulk peptidase activities were up to 15-fold higher in the fjord than in glacial rivers, whereas bulk glucosidase activities in rivers were twofold greater, despite fourfold lower cell counts. Particle-associated glucosidase activities showed similar trends by salinity, but particle-associated peptidase activities were up to fivefold higher-or, for several peptidases, only detectable-in the fjord. Bulk polysaccharide hydrolase activities also exhibited freshwater-marine contrasts: xylan hydrolysis rates were fivefold higher in rivers, while chondroitin hydrolysis rates were 30-fold greater in the fjord. Contrasting enzymatic patterns paralleled variations in bacterial community structure, with most robust compositional shifts in river-to-fjord transitions, signifying a taxonomic and genetic basis for functional differences in freshwater and marine waters. However, distinct dissolved organic matter (DOM) pools across the salinity gradient, as well as a positive relationship between several enzymatic activities and DOM compounds, indicate that DOM supply exerts a more proximate control on microbial activities. Thus, differing microbial enzymatic capabilities, community structure, and DOM composition-interwoven with salinity and water mass origins-suggest that increased meltwater may alter OM retention and processing in fjords, changing the pool of OM supplied to coastal Arctic microbial communities.

  • 256.
    Balmonte, John Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology. Univ North Carolina Chapel Hill, Dept Marine Sci, Chapel Hill, NC 27514 USA.;Univ Southern Denmark, Dept Biol, HADAL & Nordcee, Odense, Denmark..
    Simon, Meinhard
    Carl von Ossietzky Univ Oldenburg, Inst Chem & Biol Marine Environm, Oldenburg, Germany..
    Giebel, Helge-Ansgar
    Carl von Ossietzky Univ Oldenburg, Inst Chem & Biol Marine Environm, Oldenburg, Germany..
    Arnosti, Carol
    Univ North Carolina Chapel Hill, Dept Marine Sci, Chapel Hill, NC 27514 USA..
    A sea change in microbial enzymes: Heterogeneous latitudinal and depth-related gradients in bulk water and particle-associated enzymatic activities from 30 degrees S to 59 degrees N in the Pacific Ocean2021In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 66, no 9, p. 3489-3507Article in journal (Refereed)
    Abstract [en]

    Heterotrophic microbes initiate the degradation of high molecular weight organic matter using extracellular enzymes. Our understanding of differences in microbial enzymatic capabilities, especially among particle-associated taxa and in the deep ocean, is limited by a paucity of hydrolytic enzyme activity measurements. Here, we measured the activities of a broad range of hydrolytic enzymes (glucosidases, peptidases, polysaccharide hydrolases) in epipelagic to bathypelagic bulk water (nonsize-fractionated), and on particles (>= 3 mu m) along a 9800 km latitudinal transect from 30 degrees S in the South Pacific to 59 degrees N in the Bering Sea. Individual enzyme activities showed heterogeneous latitudinal and depth-related patterns, with varying biotic and abiotic correlates. With increasing latitude and decreasing temperature, lower laminarinase activities sharply contrasted with higher leucine aminopeptidase (leu-AMP) and chondroitin sulfate hydrolase activities in bulk water. Endopeptidases (chymotrypsins, trypsins) exhibited patchy spatial patterns, and their activities can exceed rates of the widely measured exopeptidase, leu-AMP. Compared to bulk water, particle-associated enzymatic profiles featured a greater relative importance of endopeptidases, as well as a broader spectrum of polysaccharide hydrolases in some locations, and latitudinal and depth-related trends that are likely consequences of varying particle fluxes. As water depth increased, enzymatic spectra on particles and in bulk water became narrower, and diverged more from one another. These distinct latitudinal and depth-related gradients of enzymatic activities underscore the biogeochemical consequences of emerging global patterns of microbial community structure and function, from surface to deep waters, and among particle-associated taxa.

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  • 257.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Reinthaler, Thomas
    University of Vienna, Austria.
    Herndl, Gerhard J.
    University of Vienna, Austria;Royal Netherlands Institute for Sea Research (NIOZ), The Netherlands.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Major Effect of Hydrogen Peroxide on Bacterioplankton Metabolism in the Northeast Atlantic2013In: PLOS ONE, E-ISSN 1932-6203, Vol. 8, no 4, article id e61051Article in journal (Refereed)
    Abstract [en]

    Reactive oxygen species such as hydrogen peroxide have the potential to alter metabolic rates of marine prokaryotes, ultimately impacting the cycling and bioavailability of nutrients and carbon. We studied the influence of H2O2 on prokaryotic heterotrophic production (PHP) and extracellular enzymatic activities (i.e., beta-glucosidase [BGase], leucine aminopeptidase [LAPase] and alkaline phosphatase [APase]) in the subtropical Atlantic. With increasing concentrations of H2O2 in the range of 100-1000 nM, LAPase, APase and BGase were reduced by up to 11, 23 and 62%, respectively, in the different water layers. Incubation experiments with subsurface waters revealed a strong inhibition of all measured enzymatic activities upon H2O2 amendments in the range of 10-500 nM after 24 h. H2O2 additions also reduced prokaryotic heterotrophic production by 36-100% compared to the rapid increases in production rates occurring in the unamended controls. Our results indicate that oxidative stress caused by H2O2 affects prokaryotic growth and hydrolysis of specific components of the organic matter pool. Thus, we suggest that oxidative stress may have important consequences on marine carbon and energy fluxes.

  • 258.
    Banitz, Thomas
    et al.
    UFZ Helmholtz Ctr Environm Res, Germany.
    Schlüter, Maja
    Stockholm Univ, Sweden.
    Lindkvist, Emilie
    Stockholm Univ, Sweden.
    Radosavljevic, Sonja
    Stockholm Univ, Sweden.
    Johansson, Lars-Göran
    Stockholm Univ, Sweden; Uppsala Univ, Sweden.
    Ylikoski, Petri
    Linköping University, Department of Management and Engineering, The Institute for Analytical Sociology, IAS. Linköping University, Faculty of Arts and Sciences. Univ Helsinki, Finland.
    Martinez Pena, Rodrigo
    Linköping University, Department of Management and Engineering, The Institute for Analytical Sociology, IAS. Linköping University, Faculty of Arts and Sciences. Stockholm Univ, Sweden.
    Grimm, Volker
    UFZ Helmholtz Ctr Environm Res, Germany.
    Model-derived causal explanations are inherently constrained by hidden assumptions and context: The example of Baltic cod dynamics2022In: Environmental Modelling & Software, ISSN 1364-8152, E-ISSN 1873-6726, Vol. 156, article id 105489Article in journal (Refereed)
    Abstract [en]

    Models are widely used for investigating cause-effect relationships in complex systems. However, often different models yield diverging causal claims about specific phenomena. Therefore, critical reflection is needed on causal insights derived from modeling. As an example, we here compare ecological models dealing with the dynamics and collapse of cod in the Baltic Sea. The models addressed different specific questions, but also vary widely in system conceptualization and complexity. With each model, certain ecological factors and mechanisms were analyzed in detail, while others were included but remained unchanged, or were excluded. Model-based causal analyses of the same system are thus inherently constrained by diverse implicit assumptions about possible determinants of causation. In developing recommendations for human action, awareness is needed of this strong context dependence of causal claims, which is often not entirely clear. Model comparisons can be supplemented by integrating findings from multiple models and confronting models with multiple observed patterns.

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  • 259.
    Bar-Am, Maya
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Akademiska sjukhuset: Befintliga geotekniska och hydrogeologiska förhållanden och dess markförutsättningar för framtida byggnationer2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Uppsala University Hospital is a large institution of vital societal function and many new buildings have been constructed and others rebuild during the past ten years. The hospital area is located on Uppsalaåsen and within a primary protection zone, i.e. there is a complex geology and requirements for the protection of the groundwater used for Uppsala’s water supply. The ground contains large sections of clay and has drastic changes in soil types. This has resulted in a subsidence problem within the hospital area. Region Uppsala has several plans regarding upcoming constructions at Uppsala University Hospital and due to the complicated soil situation is an investigation of the geotechnics and hydrogeology within the area sought for. The focus of this master thesis is on subsidence capacity and the ground water’s pressure levels. Four zones within the hospital area have been pointed out by Region Uppsala for potential future construction projects. The zones are at the parking garage T3, production kitchen, NOP-complex and new cyclotron building.

    The master thesis was divided into three parts; locating the soil layer sequence, calculation of subsidence based on CRS tests and study of the ground water’s pressure level. The soil layer sequence was construed in GeoSuite based on 474 probes conducted by the consultant company Bjerking. The probs respective soil layer was interpolated and illustrated as level curves using Topocad. Eight cross-sections were made within the zones of extra interest and the sections were made from a 3D-model created in Civil 3D. The soil layers examined throughout the master thesis were filling material, clay, granular soil, rock and ground surface. The subsidence capacity and its time were calculated based on two CRS trials and max-, min- and average values of the ground water’s pressure levels under the hospital area was computed based on 20 years of daily data retrieved from a measuring well in Stadsträdgården facilitated by Uppsala Vatten.

    The results confirm the ridge complex geology consisting of varying depths of clay under the hospital area. Several buildings will probably require deep foundations, e.g. the parking garage T3. The results also show areas of shallow layers of clay indicating lower risk of subsidence and hence will require a shallow foundation. The conducted subsidence calculations indicate that the parking garage T3 will sink 20 to 70 cm after 158 to 213 years if no foundation is implemented, which is in line with the current subsidence occurring at the building. The ground water’s pressure level has had an average value of + 2.3 m (RH2000) during the last 20 years and will probably not fluctuate in the future due to the existing decision on water management. Hence, some buildings within certain parts of the hospital area will require permission prior to construction within the primary zone. 

    The results establish a valuable overview of the hydrogeology at Uppsala University Hospital and give indications regarding how the foundations in the zones of extra interest should be dimensioned sustainable and economically. However, more data is needed, e.g. additional probes and CRS trials, to gain an increased complexity of the hospital area in respect to soil layer sequences and subsidence tendency. 

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  • 260. Baresel, Christian
    et al.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Uncertainty-Accounting Environmental Policy and Management of Water Systems2007In: Environmental Science & Technology, Vol. 41, no 10, p. 3653–3659-Article in journal (Refereed)
    Abstract [en]

    Environmental policies for water quality and ecosystem

    management do not commonly require explicit stochastic

    accounts of uncertainty and risk associated with the

    quantification and prediction of waterborne pollutant loads

    and abatement effects. In this study, we formulate and

    investigate a possible environmental policy that does require

    an explicit stochastic uncertainty account. We compare

    both the environmental and economic resource allocation

    performance of such an uncertainty-accounting environmental

    policy with that of deterministic, risk-prone and riskaverse

    environmental policies under a range of different

    hypothetical, yet still possible, scenarios. The comparison

    indicates that a stochastic uncertainty-accounting

    policy may perform better than deterministic policies over

    a range of different scenarios. Even in the absence of

    reliable site-specific data, reported literature values appear

    to be useful for such a stochastic account of uncertainty.

  • 261.
    Barrientos, Natalia
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Arctic Ocean benthic foraminifera preservation and Mg/Ca ratios: Implications for bottom water palaeothermometry2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Reconstructions of Arctic Ocean palaeotemperatures are needed to disentangle natural variability from anthropogenic changes and understand the role of ocean heat transport in forcing or providing feedbacks on Arctic climate change. Despite known complications with calcareous microfossil preservation in Arctic Ocean sediments, calcareous benthic foraminifera can be common in interglacial sequences. However, thus far they have been underutilized in palaeoceanographic studies. This thesis explores the application of the Mg/Ca palaeothermometry proxy for reconstructing bottom water temperatures (BWT) in the Arctic Ocean during the late Quaternary. This method, which is supported by previous empirical studies demonstrating a strong temperature control on trace Mg inclusion into foraminiferal shell calcite, has been applied in many ocean regions and time intervals. Until now its application in the Arctic Ocean has been sparingly explored.

    The results of this doctoral thesis are based on benthic foraminifera retrieved from marine sediment cores covering a wide geographical Arctic Ocean area including both the shallow and vast continental shelves and slopes to the intermediate-to-deep waters of the Lomonosov Ridge and Morris Jesup Rise. These provide the first benthic foraminifera Mg/Ca ratios from the central Arctic Ocean region. In the first study, mechanisms that could affect Mg incorporation in Arctic benthic foraminifera are investigated using oceanographic field data and six 'live' modern Arctic species (Elphidium clavatum, Nonionella labradorica, Cassidulina neoteretis, Oridorsalis tener, Cibicidoides wuellerstorfi and Quinqueloculina arctica). The result is new species-specific Mg/Ca–BWT field calibrations that provide important constraints at the cold end of the BWT spectrum (-2 to 1°C) (Paper I). Using the new Mg/Ca–BWT equation for E. clavatum, a palaeotemperature record was generated for the late Holocene (past ca. 4100 yr) from the western Chukchi Sea. The data showed BWT fluctuations from -2 to 1°C that are interpreted as showing pulses of warmer Pacific water inflow at 500–1000 yr periods, thus revealing multi-centennial variability in heat transport into the Arctic Ocean driven by low latitude forcings (Paper II). Complications with foraminiferal calcite preservation that limit Mg/Ca palaeothermometry in the Arctic were discovered and these are tackled in two additional papers. Anomalously high Mg content in benthic foraminifera from the central Arctic Ocean is linked to diagenetic contamination as a result of the unique oceanographic, sedimentary and geochemical environment (Paper III). Lastly, the dramatic post-recovery dissolution of foraminifera from a Chukchi Shelf sediment core during core storage is investigated and attributed to acidification driven by sulphide oxidation in this organic rich and calcite poor shelf setting (Paper IV).

    The findings of this thesis demonstrate that benthic foraminiferal Mg/Ca-palaeothermometry can be applied in the Arctic Ocean and capture small BWT change (on the order of -2 to 2°C) even at low temperatures. In practice, preservational complexities can be limiting and require special sample handling or analysis due to the high potential for diagenetic contamination in the central Arctic Ocean and rapid post coring calcite dissolution in the seasonally productive shelf seas. This Ph.D. project is a component of the multidisciplinary SWERUS-C3 (Swedish-Russian-US Arctic Ocean Climate-Cryosphere- Carbon Interactions) project that included an expedition with Swedish icebreaker Oden to the East Siberian Arctic Ocean.

  • 262.
    Barrientos, Natalia
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Arctic Ocean benthic foraminifera preservation and Mg/Ca ratios: Implications for bottom water palaeothermometry2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Reconstructions of Arctic Ocean palaeotemperatures are needed to disentangle natural variability from anthropogenic changes and understand the role of ocean heat transport in forcing or providing feedbacks on Arctic climate change. Despite known complications with calcareous microfossil preservation in Arctic Ocean sediments, calcareous benthic foraminifera can be common in interglacial sequences. However, thus far they have been underutilized in palaeoceanographic studies. This thesis explores the application of the Mg/Ca palaeothermometry proxy for reconstructing bottom water temperatures (BWT) in the Arctic Ocean during the late Quaternary. This method, which is supported by previous empirical studies demonstrating a strong temperature control on trace Mg inclusion into foraminiferal shell calcite, has been applied in many ocean regions and time intervals. Until now its application in the Arctic Ocean has been sparingly explored.

    The results of this doctoral thesis are based on benthic foraminifera retrieved from marine sediment cores covering a wide geographical Arctic Ocean area including both the shallow and vast continental shelves and slopes to the intermediate-to-deep waters of the Lomonosov Ridge and Morris Jesup Rise. These provide the first benthic foraminifera Mg/Ca ratios from the central Arctic Ocean region. In the first study, mechanisms that could affect Mg incorporation in Arctic benthic foraminifera are investigated using oceanographic field data and six 'live' modern Arctic species (Elphidium clavatum, Nonionella labradorica, Cassidulina neoteretis, Oridorsalis tener, Cibicidoides wuellerstorfi and Quinqueloculina arctica). The result is new species-specific Mg/Ca–BWT field calibrations that provide important constraints at the cold end of the BWT spectrum (-2 to 1°C) (Paper I). Using the new Mg/Ca–BWT equation for E. clavatum, a palaeotemperature record was generated for the late Holocene (past ca. 4100 yr) from the western Chukchi Sea. The data showed BWT fluctuations from -2 to 1°C that are interpreted as showing pulses of warmer Pacific water inflow at 500–1000 yr periods, thus revealing multi-centennial variability in heat transport into the Arctic Ocean driven by low latitude forcings (Paper II). Complications with foraminiferal calcite preservation that limit Mg/Ca palaeothermometry in the Arctic were discovered and these are tackled in two additional papers. Anomalously high Mg content in benthic foraminifera from the central Arctic Ocean is linked to diagenetic contamination as a result of the unique oceanographic, sedimentary and geochemical environment (Paper III). Lastly, the dramatic post-recovery dissolution of foraminifera from a Chukchi Shelf sediment core during core storage is investigated and attributed to acidification driven by sulphide oxidation in this organic rich and calcite poor shelf setting (Paper IV).

    The findings of this thesis demonstrate that benthic foraminiferal Mg/Ca-palaeothermometry can be applied in the Arctic Ocean and capture small BWT change (on the order of -2 to 2°C) even at low temperatures. In practice, preservational complexities can be limiting and require special sample handling or analysis due to the high potential for diagenetic contamination in the central Arctic Ocean and rapid post coring calcite dissolution in the seasonally productive shelf seas. This Ph.D. project is a component of the multidisciplinary SWERUS-C3 (Swedish-Russian-US Arctic Ocean Climate-Cryosphere- Carbon Interactions) project that included an expedition with Swedish icebreaker Oden to the East Siberian Arctic Ocean.

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  • 263.
    Barrientos, Natalia
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Coxall, Helen
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Lear, Caroline
    Pearce, Christof
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Muschitiello, Francesco
    O'Regan, Matt
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Stranne, Christian
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    de Boer, Agatha
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Cronin, Thomas
    Semiletov, Igor
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Late Holocene variability in Arctic Ocean Pacific Water inflow through the Bering StraitManuscript (preprint) (Other academic)
  • 264.
    Barrientos, Natalia
    et al.
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Lear, Caroline H.
    Jakobsson, Martin
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Stranne, Christian
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    O'Regan, Matt
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Cronin, Thomas M.
    Gukov, Aleksandr Y.
    Coxall, Helen K.
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Arctic Ocean benthic foraminifera Mg/Ca ratios and global Mg/Ca-temperature calibrations: New constraints at low temperatures2018In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 236, p. 240-259Article in journal (Refereed)
    Abstract [en]

    We explore the use of Mg/Ca ratios in six Arctic Ocean benthic foraminifera species as bottom water palaeothermometers and expand published Mg/Ca-temperature calibrations to the coldest bottom temperatures (<1 °C). Foraminifera were analyzed in surface sediments at 27 sites in the Chukchi Sea, East Siberian Sea, Laptev Sea, Lomonosov Ridge and Petermann Fjord. The sites span water depths of 52–1157 m and bottom water temperatures (BWT) of −1.8 to +0.9 °C. Benthic foraminifera were alive at time of collection, determined from Rose Bengal (RB) staining. Three infaunal and three epifaunal species were abundant enough for Mg/Ca analysis. As predicted by theory and empirical evidence, cold water Arctic Ocean benthic species produce low Mg/Ca ratios, the exception being the porcelaneous species Quinqueloculina arctica. Our new data provide important constraints at the cold end (<1 °C) when added to existing global datasets. The refined calibrations based on the new and published global data appear best supported for the infaunal species Nonionella labradorica (Mg/Ca = 1.325 ± 0.01 × e^(0.065 ± 0.01 × BWT), r2 = 0.9), Cassidulina neoteretis (Mg/Ca = 1.009 ± 0.02 × e^(0.042 ± 0.01 × BWT), r2 = 0.6) and Elphidium clavatum (Mg/Ca = 0.816 ± 0.06 + 0.125 ± 0.05 × BWT, r2 = 0.4). The latter is based on the new Arctic data only. This suggests that Arctic Ocean infaunal taxa are suitable for capturing at least relative and probably semi-quantitative past changes in BWT. Arctic Oridorsalis tener Mg/Ca data are combined with existing O. umbonatus Mg/Ca data from well saturated core-tops from other regions to produce a temperature calibration with minimal influence of bottom water carbonate saturation state (Mg/Ca = 1.317 ± 0.03 × e^(0.102 ± 0.01 BWT), r2 = 0.7). The same approach for Cibicidoides wuellerstorfi yields Mg/Ca = 1.043 ± 0.03 × e^(0.118 ± 0.1 BWT), r2 = 0.4. Mg/Ca ratios of the porcelaneous epifaunal species Q. arctica show a clear positive relationship between Mg/Ca and Δ[CO32−] indicating that this species is not suitable for Mg/Ca-palaeothermometry at low temperatures, but may be useful in reconstructing carbonate system parameters through time.

  • 265.
    Barrientos, Natalia
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Lear, Caroline H.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Stranne, Christian
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    O'Regan, Matt
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Cronin, Thomas M.
    Gukov, Aleksandr Y.
    Coxall, Helen K.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Arctic Ocean benthic foraminifera Mg/Ca ratios and global Mg/Ca-temperature calibrations: New constraints at low temperatures2018In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 236, p. 240-259Article in journal (Refereed)
    Abstract [en]

    We explore the use of Mg/Ca ratios in six Arctic Ocean benthic foraminifera species as bottom water palaeothermometers and expand published Mg/Ca-temperature calibrations to the coldest bottom temperatures (<1 °C). Foraminifera were analyzed in surface sediments at 27 sites in the Chukchi Sea, East Siberian Sea, Laptev Sea, Lomonosov Ridge and Petermann Fjord. The sites span water depths of 52–1157 m and bottom water temperatures (BWT) of −1.8 to +0.9 °C. Benthic foraminifera were alive at time of collection, determined from Rose Bengal (RB) staining. Three infaunal and three epifaunal species were abundant enough for Mg/Ca analysis. As predicted by theory and empirical evidence, cold water Arctic Ocean benthic species produce low Mg/Ca ratios, the exception being the porcelaneous species Quinqueloculina arctica. Our new data provide important constraints at the cold end (<1 °C) when added to existing global datasets. The refined calibrations based on the new and published global data appear best supported for the infaunal species Nonionella labradorica (Mg/Ca = 1.325 ± 0.01 × e^(0.065 ± 0.01 × BWT), r2 = 0.9), Cassidulina neoteretis (Mg/Ca = 1.009 ± 0.02 × e^(0.042 ± 0.01 × BWT), r2 = 0.6) and Elphidium clavatum (Mg/Ca = 0.816 ± 0.06 + 0.125 ± 0.05 × BWT, r2 = 0.4). The latter is based on the new Arctic data only. This suggests that Arctic Ocean infaunal taxa are suitable for capturing at least relative and probably semi-quantitative past changes in BWT. Arctic Oridorsalis tener Mg/Ca data are combined with existing O. umbonatus Mg/Ca data from well saturated core-tops from other regions to produce a temperature calibration with minimal influence of bottom water carbonate saturation state (Mg/Ca = 1.317 ± 0.03 × e^(0.102 ± 0.01 BWT), r2 = 0.7). The same approach for Cibicidoides wuellerstorfi yields Mg/Ca = 1.043 ± 0.03 × e^(0.118 ± 0.1 BWT), r2 = 0.4. Mg/Ca ratios of the porcelaneous epifaunal species Q. arctica show a clear positive relationship between Mg/Ca and Δ[CO32−] indicating that this species is not suitable for Mg/Ca-palaeothermometry at low temperatures, but may be useful in reconstructing carbonate system parameters through time.

  • 266. Bartolino, Valerio
    et al.
    Tian, Huidong
    Bergstrom, Ulf
    Jounela, Pekka
    Aro, Eero
    Dieterich, Christian
    SMHI, Research Department, Oceanography.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Cardinale, Massimiliano
    Bland, Barbara
    Casini, Michele
    Spatio-temporal dynamics of a fish predator: Density-dependent and hydrographic effects on Baltic Sea cod population2017In: PLOS ONE, E-ISSN 1932-6203, Vol. 12, no 2, article id e0172004Article in journal (Refereed)
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  • 267.
    Bartosova, Alena
    et al.
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    De Lavenne, Alban
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Strömqvist, Johan
    SMHI, Research Department, Hydrology.
    Large-Scale Hydrological and Sediment Modeling in Nested Domains under Current and Changing Climate2021In: Journal of hydrologic engineering, ISSN 1084-0699, E-ISSN 1943-5584, Vol. 26, no 5, article id 05021009Article in journal (Refereed)
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    Large-Scale Hydrological and Sediment Modeling in Nested Domains under Current and Changing Climate
  • 268.
    Bartosova, Alena
    et al.
    SMHI, Research Department, Hydrology.
    Capell, Réne
    SMHI, Research Department, Hydrology.
    Olesen, Jorgen E.
    Jabloun, Mohamed
    Refsgaard, Jens Christian
    Donnelly, Chantal
    SMHI, Research Department, Hydrology.
    Hyytiainen, Kari
    Pihlainen, Sampo
    Zandersen, Marianne
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Future socioeconomic conditions may have a larger impact than climate change on nutrient loads to the Baltic Sea2019In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 48, no 11, p. 1325-1336Article in journal (Refereed)
  • 269.
    Basirat, Farzad
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Process Models for CO2 Migration and Leakage: Gas Transport, Pore-Scale Displacement and Effects of Impurities2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Geological Carbon Storage (GCS) is considered as one of the key techniques to reduce the rate of atmospheric emissions of CO2 and thereby to contribute to controlling the global warming. A successful application of a GCS project requires the capability of the formation to trap CO2 for a long term. In this context, processes related to CO2 trapping and also possible leakage of CO2 to the near surface environment need to be understood. The overall aim of this thesis is to understand the flow and transport of CO2 through porous media in the context of geological storage of CO2. The entire range of scales, including the pore scale, the laboratory scale, the field experiment scale and the industrial scale of CO2 injection operation are addressed, and some of the key processes investigated by means of experiments and modeling.  First, a numerical model and laboratory experimental setup were developed to investigate the CO2 gas flow, mimicking the system in the near-surface conditions in case a leak from the storage formation should occur. The system specifically addressed the coupled flow and mass transport of gaseous CO2 both in the porous domain as well as the free flow domain above it. The comparison of experiments and modelling results showed a very good agreement indicating that the model developed can be applied to evaluate monitoring and surface detection of potential CO2 leakage. Second, the field scale CO2 injection test carried out in a shallow aquifer in Maguelone, France was analyzed and modeled. The results showed that Monte Carlo simulations accounting for the heterogeneity effects of the permeability field did capture the key observations of the monitoring data, while a homogeneous model could not represent them. Third, a numerical model based on phase-field method was developed and model simulations carried out addressing the effect of wettability on CO2-brine displacement at the pore-scale. The results show that strongly water-wet reservoirs provide a better potential for the dissolution trapping, due to the increase of interface between CO2 and brine with very low contact angles. The results further showed that strong water-wet conditions also imply a strong capillary effect, which is important for residual trapping of CO2. Finally, numerical model development and model simulations were carried out to address the large scale geological storage of CO2 in the presence of impurity gases in the CO2 rich phase. The results showed that impurity gases N2 and CH4 affected the spatial distribution of the gas (the supercritical CO2 rich phase), and a larger volume of reservoir is needed in comparison to the pure CO2 injection scenario. In addition, the solubility trapping significantly increased in the presence of N2 and CH4

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  • 270.
    Basirat, Farzad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Jung, Byeongju
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, South Korea.
    Yang, Zhibing
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Niemi, Auli
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Numerical simulation of geological storage of CO2 with impurities in large scale saline aquiferManuscript (preprint) (Other academic)
  • 271.
    Basirat, Farzad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Tsang, Chin-Fu
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Lawrence Berkeley Natl Lab, Energy Geosci Div, Berkeley, CA USA..
    Tatomir, Alexandru
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Guglielmi, Yves
    Lawrence Berkeley Natl Lab, Energy Geosci Div, Berkeley, CA USA..
    Dobson, Patrick
    Lawrence Berkeley Natl Lab, Energy Geosci Div, Berkeley, CA USA..
    Cook, Paul
    Lawrence Berkeley Natl Lab, Energy Geosci Div, Berkeley, CA USA..
    Dessirier, Benoit
    Stockholm Univ, Baltic Sea Ctr, Stockholm, Sweden..
    Juhlin, Christopher
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
    Niemi, Auli
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hydraulic Modeling of Induced and Propagated Fractures: Analysis of Flow and Pressure Data From Hydromechanical Experiments in the COSC-1 Deep Borehole in Crystalline Rock Near Åre, Sweden2021In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 57, no 11, article id e2020WR029484Article in journal (Refereed)
    Abstract [en]

    To characterize the coupled hydromechanical behavior of rock fractures, the step-rate injection method for fracture in-situ properties (SIMFIP) was conducted with a specialized downhole probe developed by Guglielmi et al. (2014, https://doi.org/10.1007/s00603-013-0517-1). In June 2019, a field campaign was carried out near Åre, Sweden, where the SIMFIP probe was applied in the Collisional Orogeny in the Scandinavian Caledonides-1 scientific borehole to understand the dynamics of injection-induced fracture initiation, fracture opening, and shearing due to water injection-withdrawal in a borehole interval isolated by two packers. Three intervals were investigated at ∼500 m depth: (a) an unfractured section (intact rock), (b) a section with non-conductive fractures, and (c) a section with hydraulically conductive fractures. Pressure, injection flow rate, and borehole wall displacement were simultaneously measured during the tests. In the present study, the geometry of the induced fracture and deformation of existing fractures at different time stages of the tests are determined based on a hydrologic model by using the measured pressure and flow data during each time stage of the experiment. A numerical model for the fluid flow within the fracture and the packed-off borehole interval is implemented within COMSOL Multiphysics. By matching model simulations with observed data for all three sections, estimates of the induced and propagated fractures' radius and aperture at successive time stages have been obtained in each case. We could also determine the non-linear relationship between fracture aperture and pressure for values above fracture opening pressures. The model results provide insights for the understanding of pressure-induced fracture initiation and propagation in crystalline rock.

  • 272.
    Basirat, Farzad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Yang, Zhibing
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
    Niemi, Auli
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Pore-scale modeling of wettability effects on CO2–brine displacement during geological storage2017In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 109, p. 181-195Article in journal (Refereed)
    Abstract [en]

    Wetting properties of reservoir rocks and caprocks can vary significantly, and they strongly influence geological storage of carbon dioxide in deep saline aquifers, during which CO2 is supposed to displace the resident brine and to become permanently trapped. Fundamental understanding of the effect of wettability on CO2-brine displacement is thus important for improving storage efficiency and security. In this study, we investigate the influence of wetting properties on two-phase flow of CO2 and brine at the pore scale. A numerical model based on the phase field method is implemented to simulate the two-phase flow of CO2-brine in a realistic pore geometry. Our focus is to study the pore-scale fluid-fluid displacement mechanisms under different wetting conditions and to quantify the effect of wettability on macroscopic parameters such as residual brine saturation, capillary pressure, relative permeability, and specific interfacial area. Our simulation results confirm that both the trapped wetting phase saturation and the normalized interfacial area increase with decreasing contact angle. However, the wetting condition does not appear to influence the CO2 breakthrough time and saturation. We also show that the macroscopic capillary pressures based on the pressure difference between inlet and outlet can differ significantly from the phase averaging capillary pressures for all contact angles when the capillary number is high ( log Ca > -5). This indicates that the inlet-outlet pressure difference may not be a good measure of the continuum-scale capillary pressure. In addition, the results show that the relative permeability of CO2 can be significantly lower in strongly water-wet conditions than in the intermediate-wet conditions.

  • 273.
    Bastias, Elliot
    et al.
    Integrative Freshwater Ecology Group, Centre d’Estudis Avançats de Blanes, Blanes, Girona, Spain.
    Ribot, Miquel
    Jonsson, Micael
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sabater, Francesc
    Martí, Eugènia
    Chemical and optical properties of leachates from different riparian particulate organic matter sources influence instream microbial activity2020In: Freshwater Science, ISSN 2161-9549, E-ISSN 2161-9565, Vol. 39, no 4, p. 812-823Article in journal (Refereed)
    Abstract [en]

    The release of soluble compounds (i.e., leachates) from allochthonous coarse particulate organic matter (CPOM) into stream water can be an important source of dissolved organic matter (DOM) and nutrients for instream microbial activity. Here, we assessed variability in the chemistry and the composition of DOM of leachates from different CPOM sources and examined how these characteristics influenced the activity of microbial assemblages in streams. Specifically, we considered leaf litter from 6 tree species that are broadly distributed in riparian zones of the Mediterranean region, a mixture of fruits from some of these species, and a mixture of twigs. We analyzed the leachates from each CPOM source for the concentration of dissolved forms of carbon, nitrogen, and phosphorus, as well as for the composition of DOM based on optical indices associated with the degree of aromaticity and molecular weight. Under laboratory conditions, we used the Resazurin–Resorufin system to estimate the microbial metabolic activity associated with each leachate type. Microbial metabolic activity varied among leachates from different CPOM sources and was positively related to the degree of aromaticity and the NO3 concentration of leachates. Hence, certain types of riparian CPOM inputs can constitute sources of high-quality DOM and dissolved nutrients for instream microbial assemblages. Thus, management of riparian vegetation should consider variation in leachate properties among plant species, as they can influence dissolved organic carbon and nutrient dynamics and heterotrophic activity in stream ecosystems.

  • 274.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sundgren, Ingrid
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Natchimuthu, Sivakiruthika
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Reyier, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Gålfalk, Magnus
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Technical Note: Cost-efficient approaches to measure carbon dioxide (CO2) fluxes and concentrations in terrestrial and aquatic environments using mini loggers2015In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 12, no 12, p. 3849-3859Article in journal (Refereed)
    Abstract [en]

    Fluxes of CO2 are important for our understanding of the global carbon cycle and greenhouse gas balances. Several significant CO2 fluxes in nature may still be unknown as illustrated by recent findings of high CO2 emissions from aquatic environments, previously not recognized in global carbon balances. Therefore, it is important to develop convenient and affordable ways to measure CO2 in many types of environments. At present, direct measurements of CO2 fluxes from soil or water, or CO2 concentrations in surface water, are typically labor intensive or require costly equipment. We here present an approach with measurement units based on small inexpensive CO2 loggers, originally made for indoor air quality monitoring, that were tested and adapted for field use. Measurements of soil-atmosphere and lake-atmosphere fluxes, as well as of spatiotemporal dynamics of water CO2 concentrations (expressed as the equivalent partial pressure, pCO(2aq)) in lakes and a stream network are provided as examples. Results from all these examples indicate that this approach can provide a cost- and labor-efficient alternative for direct measurements and monitoring of CO2 flux and pCO(2aq) in terrestrial and aquatic environments.

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  • 275.
    Bastviken, Paulina
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Flood Risk Mapping in Africa: Exploring the Potentials and Limitations of SRTM Data in the Lower Limpopo, Mozambique2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Many regions in Africa are presently faced with an increasing flood risk due to impending climate change and population growth. One useful mitigation strategy to decrease this risk would be to map it, so that urban planning, warnings systems and emergency response subsequently could be designed to reduce societal vulnerability. This is, however, not widely feasible on the African continent, as developing countries often lack access to the topography and discharge data required to produce high- quality flood risk maps. To seek a way around this problem, on-going research is investigating the possibility of obtaining alternative model inputs, by using global datasets of elevation, derived from remote sensing, and methods to estimate flood flows. This thesis presents a case study within this context where the aim was to determine the accuracy of an African catchment-scale flood map, produced with the satellite product SRTM (Shuttle Radar Topography Mission) as topography input, and to explore the potentials and limitations of such a model scheme. Two high-magnitude floods, occurring in year 2000 and 2013 in the Lower Limpopo Basin (Mozambique), were modelled for inundation extent, using a no-channel 2D model built for the LISFLOOD-FP flood modelling software. Flood water levels were also simulated to assess the models vertical performance. Model outcomes were evaluated against satellite imagery and recordings of high watermarks, adjusting the value representing the roughness of the floodplain to optimize flood extent correspondence. Due to different hydrograph dynamics, simulations of the two floods required different values of roughness (0.02 and 0.09 s m-1/3) to reach maximum accuracy (F = 0.59 and 0.64, respectively). However, the results also indicated that a model calibrated with a flood of relatively low return period potentially could be used to map rare flood events. Simulation inaccuracies were mainly attributed to (1) reservoirs and streams, temporarily connecting to the river system during high flow conditions, (2) limitations of the topography data, in terms of recognizing riverbed geometry and floodplain micro-topography, and (3) cloud cover, reducing the accuracy of flood extent reference data. The vertical simulation accuracy, with an average error of ± 2 m, was well within the uncertainty bounds of input data. Errors were in this case ascribed the SRTM’s representation of high slope terrain and possible radar speckles in urban areas. The findings of this study indicate that there is high potential in using SRTM data for mapping of high-magnitude flood risk in Africa, but also that consideration to river system complexity is crucial. 

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  • 276.
    Bastviken, Paulina
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Soil solution DOC dynamics during winter in boreal hillslopes2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When plants and animals die they are decomposed into microscopic particles of organic carbon. In the ground, these carbon particles are dissolved in the soil water and eventually transported to the streamchannel with the flow of the groundwater. Today the quantities of dissolved organic carbon (DOC) have been observed to increase in many lakes and streams around the world, which constitute a threat against the water quality and ecologic environment of these surface waters. The amount of organic carbon that is dissolved and transported in the soil water is mainly controlled by processes related to temperature and hydrology, two factors which vary seasonally. Because of difficulties to sample soil water at temperatures below 0°C studies of DOC transport between soil and water during the winter season are limited. This study therefore conducted a winter sampling of soil water, with the focus on DOC. Samples were collected in March 2014 at sites along three hillslopes, orthogonal to two streams, in a typical Swedish boreal forest northwest of Umeå. The soil water was extracted with the help of suction lysimeters installed at different depths in the soil, and heating equipmentpowered by batteries. The collected samples were analyzed for DOC concentration and absorbance after which the results were grouped together with results from previous sampling campaigns, conducted in the summer and autumn of 2013. Parallel to this, data representing a longer time series (2009 to 2012) at another hillslope was processed. During the summer and autumn an increase in DOC concentration was observed. The increase was assumed to be caused by high production and effective degradation of organic matter in the soil during this warm period. Generally, a decrease in the DOC concentration then followed during the winter season. One possible reason for this decrease could be that the bacterial degradation in the soil continued, during the winter, and transformed the dissolved carbon into CO2 and CH4. Another possibility is that the DOC was flushed into the streams by autumn rain events. The study also found differences concerning the DOC concentration and character in the soil water, as well as the seasonal variation of these parameters, with soil depth and distance from the stream along the hillslope profile. These differences could be correlated to the organic content of the soil, from which the soil water had been extracted.

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  • 277.
    Bathia, PK
    et al.
    IIT Dehli.
    Bergström, Sten
    SMHI, Research Department, Hydrology.
    Persson, Magnus
    SMHI.
    Application of the distributed HBV-6 model to the upper Narmada basin in India1984Report (Other academic)
    Abstract [en]

    The application of the HBV-6 conceptual runoff model to the Upper Narmada basin is surnmarized. The work includes an extensive investigation of the homogeneity of the precipitation stations anda discussion on the estimates of the potential evapotranspiration. A comparison between a lumped and a distributed model structure is made. Finally is shown how the model can be transformed into a set of nomograms for day-today simulations without support from computer.

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    Application of the distributed HBV-6 model to the upper Narmada basin in India
  • 278. Bauer, Barbara
    et al.
    Gustafsson, Bo G.
    Hyytiainen, Kari
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Mueller-Karulis, Baerbel
    Saraiva, Sofia
    SMHI, Research Department, Oceanography.
    Tomczak, Maciej T.
    Food web and fisheries in the future Baltic Sea2019In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 48, no 11, p. 1337-1349Article in journal (Refereed)
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  • 279. Bauer, Barbara
    et al.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Casini, Michele
    Hoff, Ayoe
    Margonski, Piotr
    Orio, Alessandro
    Saraiva, Sofia
    SMHI, Research Department, Oceanography.
    Steenbeek, Jeroen
    Tomczak, Maciej T.
    Reducing eutrophication increases spatial extent of communities supporting commercial fisheries: a model case study2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 4, p. 1306-1317Article in journal (Refereed)
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  • 280. Bauer, Barbara
    et al.
    Meier, Markus
    SMHI, Research Department, Oceanography.
    Casini, Michele
    Hoff, Ayoe
    Margonski, Piotr
    Orio, Alessandro
    Saraiva, Sofia
    SMHI, Research Department, Oceanography.
    Steenbeek, Jeroen
    Tomczak, Maciej T.
    Reducing eutrophication increases spatial extent of communities supporting commercial fisheries: a model case study (vol 75, pg 1155, 2018)2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 3, p. 1155-1155Article in journal (Refereed)
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  • 281. Bayer-Raich, Martí
    et al.
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Teutsch, Georg
    Comment on “Analysis of groundwater contamination using concentration-time series recorded during an integral pumping test: Bias introduced by strong concentration gradients within the plume” by Allelign Zeru and Gerhard Schäfer2007In: Journal of Contaminant Hydrology, ISSN 0169-7722, Vol. 90, no 3-4, p. 240-251Article in journal (Refereed)
    Abstract [en]

    We consider the results of a recent paper in this journal [Zeru, A. and Schäfer, G., 2005. Analysis of groundwater contamination using concentration–time series recorded during an integral pumping test: Bias introduced by strong concentration gradients within the plume. Journal of Contaminant Hydrology 81 (2005) 106–124], which addresses the field-scale characterisation of contaminant plumes in groundwater. There, it is concluded that contaminant concentration gradients can bias Integral Pumping Test (IPT) interpretations considerably, in particular if IPTs are conducted in advective fronts of contaminant plumes. We discuss implications of this setting and also argue that the longitudinal and transverse dispersivities used in the examples of Zeru and Schäfer (2005) of up to 30 m and 3 m, respectively, are generally very high for the here relevant capture zone scale (b20 m). However, regardless of both longitudinal and transverse concentration gradients, we further show through a counter-example that IPT results are unbiased as long as the concentration attenuation along the flow direction is linear over the capture zone extent.

  • 282. Bazilian, Morgan
    et al.
    Rogner, Holger
    Howells, Mark
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Hermann, Sebastian
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Arent, Douglas
    Gielen, Dolf
    Steduto, Pasquale
    Mueller, Alexander
    Komor, Paul
    Tol, Richard S.J.
    Yumkella, Kandeh K.
    Considering the energy, water and food nexus: Towards an integrated modelling approach2011In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, no 12, p. 7896-7906Article in journal (Refereed)
    Abstract [en]

    The areas of energy, water and food policy have numerous interwoven concerns ranging from ensuring access to services, to environmental impacts to price volatility. These issues manifest in very different ways in each of the three "spheres", but often the impacts are closely related. Identifying these interrelationships a priori is of great importance to help target synergies and avoid potential tensions. Systems thinking is required to address such a wide swath of possible topics. This paper briefly describes some of the linkages at a high-level of aggregation - primarily from a developing country perspective - and via case studies, to arrive at some promising directions for addressing the nexus. To that end, we also present the attributes of a modelling framework that specifically addresses the nexus, and can thus serve to inform more effective national policies and regulations. While environmental issues are normally the 'cohesive principle' from which the three areas are considered jointly, the enormous inequalities arising from a lack of access suggest that economic and security-related issues may be stronger motivators of change. Finally, consideration of the complex interactions will require new institutional capacity both in industrialised and developing countries.

  • 283.
    Beckholmen, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Källor i Lagga, en uppländsk slättbygd: Geografisk och geologisk påverkan på källvattens egenskaper2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For centuries, springs have played a significant role in our society as water supplies, reasons for where to settle down, and in folklore. There are different reasons why and where a spring forms, e.g. in what kind of soil it has its outflow. Geographic and geochemical surroundings have an influence on spring-water quality.For this project some of the springs in the Lagga perish, Knivsta municipality, Sweden, were selected for a closer study. Water samples were collected from springs for analysis. A short-term study was performed of temperature and conductivity changes during spring 2014. The investigated springs of this project were divided into four major groups according to their location in the landscape and their chemical properties: 1) springs that have their outflow in clay in valley bottoms, 2) springs that lie in the transition between glacial till soil and clay, 3) springs in till soil, and 4) springs in till soil with large boulders. Analyses show that the ion content in spring-water is higher in the valley than in the surrounding forest tills. Together with previous data it is shown that temperature and conductivity are more stable in the springs in the valley clay than in the uphill springs in till.

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    Källor i Lagga, en uppländsk slättbygd: Geografisk och geologisk påverkan påkällvattens egenskaper
  • 284.
    Behboudian, Massoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Anamaghi, Sara
    Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran.
    Kerachian, Reza
    School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Kalantari, Zahra
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Comparison of three group decision-making frameworks for evaluating resilience time series of water resources systems under uncertainty2024In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 158, article id 111269Article in journal (Refereed)
    Abstract [en]

    This study compared three uncertainty-based decision-making frameworks (considering/not considering the hierarchical structure of stakeholders) using resilience-based indices for evaluating different water resources management (WRM) scenarios under the impacts of climate change. The first step involved identifying significant stakeholders in the study area and establishing their relative weights. In the next step, stakeholders were asked to evaluate the management scenarios in the three different decision-making frameworks based on their decision criteria (nine resilience-based indices, implementation cost, and employment). Different types of weights (explicit and interval) were assigned to each stakeholder and their decision criteria, to account for the uncertainty associated with estimating their respective weights. This methodology was applied to the case of the Zarrinehrud River basin in northwest Iran. The best management scenario identified (MSC1346) was able increase lake elevation by 2.6 m (from 1271.3 m to 1273.9 m), improve the resilience of the system by 25 %, and enhance provisioning ecosystem services such as water and food supply and regulating services such as air quality. Comparing the results of the three decision-making frameworks revealed that the two which considered the hierarchical structure of stakeholders were more effective in determining the best scenario. The best scenario selected in the framework that ignored the hierarchical structure of stakeholders (MSC13567) had USD 202 million higher overall implementation and construction costs and gave a negligible difference in resilience value (0.04 difference) compared with scenario MSC1346.

  • 285.
    Behboudian, Massoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Univ Tehran, Coll Engn, Sch Civil Engn, Tehran, Iran..
    Anamaghi, Sara
    K N Toosi Univ Technol, Fac Civil Engn, Tehran, Iran..
    Mahjouri, Najmeh
    K N Toosi Univ Technol, Fac Civil Engn, Tehran, Iran..
    Kerachian, Reza
    Univ Tehran, Coll Engn, Sch Civil Engn, Tehran, Iran..
    Enhancing the resilience of ecosystem services under extreme events in socio-hydrological systems: A spatio-temporal analysis2023In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 397, p. 136437-, article id 136437Article in journal (Refereed)
    Abstract [en]

    Due to the adverse impacts of severe droughts on various aspects of human life and ecosystem services (ESs), the spatio-temporal assessment of the resilience of ESs under droughts is essential. In this paper, we propose a new methodology for assessing ESs-based resilience, taking into account the seven resilience principles: a) redun-dancy and diversity, b) managing connectivity, c) managing slow variables and their feedback, d) complex adaptive system (CAS) thinking, e) experimentation and learning, f) broadening participation, and g) polycentric governance. These principles enable us to consider the main social, political, hydrological, economic, and environmental aspects concerning resilience which have been overlooked in previous studies. The methodology is evaluated by applying it to Zarrinehroud River Basin (ZRB) in north-western Iran. A set of qualitative and quantitative criteria and their sub-criteria are proposed for quantifying the ES-based resilience and generating time series of resilience against severe droughts in several sub-basins in the study area. To evaluate the criteria and sub-criteria, the required data are derived from calibrated SWAT and MODSIM models as well as experts' judjments. The time series of ES-based resilience under 128 Water and Environmental Resources Management (WERM) scenarios (for enhancing agricultural practices, altering and modernizing irrigation methods, improving irrigation network and drainage facilities) and Climate Change (CC) scenarios (RCP 4.5, RCP6.0, and RCP 8.5) are derived for each sub-basin based on short-term (2020-2049) and long-term (2020-2098) periods. The low resilience values (0.53-0.6) of all sub-basins under the base management scenario (the status quo scenario (SC0)) illustrate the need for implementing some projects to enhance the ESs in the study area. The results show that the WERM scenario SC12346 can improve the values of the resilience criterion in sub-basins up to 0.85 and reduce the vulnerability of the study area to droughts. By evaluating all management scenarios, scenario SC12346 is reported as the best scenario, since it can significantly increase the resilience of all sub-basins against extreme droughts with an acceptable cost of 636 million US dollars compared to other scenarios. Under this WERM scenario, the resilience values of sub-basins increase up to 40%. This scenario suggests implementing a set of projects such as improving irrigation networks and drainage facilities.

  • 286.
    Behboudian, Massoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Kerachian, Reza
    School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Motlaghzadeh, Kasra
    Department of System Design Engineering, University of Waterloo, Waterloo, Canada.
    Ashrafi, Saeed
    Department of Engineering System and Environment, University of Virginia, Charlottesville, VA, USA.
    Application of multi-agent decision-making methods in hydrological ecosystem services management2023In: MethodsX, ISSN 1258-780X, E-ISSN 2215-0161, Vol. 10, article id 102130Article in journal (Refereed)
    Abstract [en]

    In this paper, a methodology is presented for managing hydrological ecosystem services by taking into account the hierarchy of stakeholders involved in the decision-making process. With this in mind, a water allocation model is first used for allocating water resources to demands. Then, several ecosystem services (ESs)-based criteria are defined to evaluate hydrological ESs of water resources management policies. A set of water and environmental resources management strategies (alternatives) are defined for decision-makers, and several drought management strategies are determined to decrease the area of key crops and water demands of agricultural nodes. To model a multi-agent multi-criteria decision-making problem for managing hydrological ESs, three main steps are considered as follows: • Different ES-based criteria (i.e., economic profit, NPP,1 and ecological index) are defined, and their grade-based values are estimated. • Several strategies are defined for stakeholders at different levels. • A recursive evidential reasoning (ER) approach, which considers a hierarchical structure for decision-makers and a leader-follower game, is used to select the best strategy for each decision-maker.The applicability and efficiency of the methodology are illustrated by applying it to a real-world case study. The methodology is general and can be easily applied to other study areas.

  • 287. Bejarano, Maria Dolores
    et al.
    Garcia-Palacios, Jaime H.
    Sordo-Ward, Alvaro
    Garrote, Luis
    Nilsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.
    A New Tool for Assessing Environmental Impacts of Altering Short-Term Flow and Water Level Regimes2020In: Water, E-ISSN 2073-4441, Vol. 12, no 10, article id 2913Article in journal (Refereed)
    Abstract [en]

    The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify and quantify their deviation from unaltered states. The pronunciation of the acronym refers to the recording interval of input data (i.e., instant). We compared InSTHAn with the tool COSH-Tool in a characterization of the subdaily flow variability of the Colorado River downstream from the Glen Canyon dam, and in an evaluation of the effects of the dam on this variability. Both tools captured the hydropeaking caused by a dam operation, but only InSTHAn quantified the alteration of key flow attributes, highlighting significant increases in the range of within-day flow variations and in their rates of change. This information is vital to evaluate the potential ecological consequences of the hydrological alteration, and whether they may be irreversible, making InSTHAn a key tool for river flow management.

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  • 288. Bejarano, Maria Dolores
    et al.
    Nilsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gonzales del Tanago, Marta
    Marchamalo, Miguel
    Responses of riparian trees and shrubs to flow regulationalong a boreal stream in northern Sweden2011In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 56, no 5, p. 853-866Article in journal (Refereed)
    Abstract [en]

    1. Flow dynamics is a major determinant of riparian plant communities. Therefore, flowregulation may heavily affect riparian ecosystems. Despite the large number of damsworldwide, little specific information is available on the longitudinal impacts of dams onvegetation, for example how far downstream and at what degree of regulation a dam on ariver can influence riparian woodlands.

    2. We quantified the long-term responses of riparian trees and shrubs to flow regulation byidentifying their lateral distribution and habitat conditions along a boreal river in northernSweden that has been regulated by a single dam since 1948. The regulation has reducedannual flow fluctuations, this effect being largest at the dam, downstream from which itprogressively decreases following the entrance of free-flowing tributaries.

    3. We related changes in the distribution patterns, composition, abundance and richness oftree and shrub species to the degree of regulation along the river downstream from thedam. Regulation has triggered establishment of trees and shrubs closer to the channel,making it possible to measure ecological impacts of flow regulation as differences invegetation attributes relative to the positions of tree and shrub communities establishedbefore and after regulation.

    4. Trees and shrubs had migrated towards the mid-channel along the entire study reach,but the changes were largest immediately downstream of the dam. Shrubs were mostimpacted by flow regulation in terms of lateral movement, but the effect on trees extendedfurthest downstream.

    5. The species composition of trees progressively returned to its pre-regulation state withdistance downstream, but entrance of free-flowing tributaries and variation in channelmorphology and substratum caused local deviations. Species richness after regulationincreased for trees but decreased for shrubs. The changes in species composition andrichness of trees and shrubs showed no clear downstream patterns, suggesting that otherfactors than the degree of regulation were more important in governing life form.

  • 289.
    Bejarano, Maria Dolores
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sordo-Ward, Alvaro
    Alonso, Carlos
    Nilsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Characterizing effects of hydropower plants on sub-daily flow regimes2017In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 550, p. 186-200Article in journal (Refereed)
    Abstract [en]

    A characterization of short-term changes in river flow is essential for understanding the ecological effects of hydropower plants, which operate by turning the turbines on or off to generate electricity following variations in the market demand (i.e., hydropeaking). The goal of our study was to develop an approach for characterizing the effects of hydropower plant operations on within-day flow regimes across multiple dams and rivers. For this aim we first defined ecologically meaningful metrics that provide a full representation of the flow regime at short time scales from free-flowing rivers and rivers exposed to hydropeaking. We then defined metrics that enable quantification of the deviation of the altered short-term flow regime variables from those of the unaltered state. The approach was successfully tested in two rivers in northern Sweden, one free-flowing and another regulated by cascades of hydropower plants, which were additionally classified based on their impact on short-term flows in sites of similar management. The largest differences between study sites corresponded to metrics describing sub-daily flow magnitudes such as amplitude (i.e., difference between the highest and the lowest hourly flows) and rates (i.e., rise and fall rates of hourly flows). They were closely followed by frequency-related metrics accounting for the numbers of within-day hourly flow patterns (i.e., rises, falls and periods of stability of hourly flows). In comparison, between-site differences for the duration-related metrics were smallest. In general, hydropeaking resulted in higher within-day flow amplitudes and rates and more but shorter periods of a similar hourly flow patterns per day. The impacted flow feature and the characteristics of the impact (i.e., intensity and whether the impact increases or decreases whatever is being described by the metric) varied with season. Our approach is useful for catchment management planning, defining environmental flow targets, prioritizing river restoration or dam reoperation efforts and contributing information for relicensing hydropower dams. 

  • 290. Beldowski, Jacek
    et al.
    Klusek, Zygmunt
    Szubska, Marta
    Turja, Raisa
    Bulczak, Anna I.
    Rak, Daniel
    Brenner, Matthias
    Lang, Thomas
    Kotwicki, Lech
    Grzelak, Katarzyna
    Jakacki, Jaromir
    Fricke, Nicolai
    Ostin, Anders
    Olsson, Ulf
    Fabisiak, Jacek
    Garnaga, Galina
    Nyholm, Jenny Rattfelt
    Majewski, Piotr
    Broeg, Katja
    Soderstrom, Martin
    Vanninen, Paula
    Popiel, Stanislaw
    Nawala, Jakub
    Lehtonen, Kari
    Berglind, Rune
    Umeå University, Faculty of Science and Technology, European CBRNE Center.
    Schmidt, Beata
    Chemical Munitions Search & Assessment-An evaluation of the dumped munitions problem in the Baltic Sea2016In: Deep-sea research. Part II, Topical studies in oceanography, ISSN 0967-0645, E-ISSN 1879-0100, Vol. 128, p. 85-95Article in journal (Refereed)
    Abstract [en]

    Chemical Munitions Search & Assessment (CHEMSEA) project has performed studies on chemical weapon (CW) detection, sediment pollution and spreading as well as biological effects of chemical warfare agents (CWAs) dumped in the Baltic Sea. Results suggest that munitions containing CWAs are more scattered on the seafloor than suspected, and previously undocumented dumpsite was discovered in Gdansk Deep. Pollution of sediments with CWA degradation products was local and close to the detected objects; however the pollution range was larger than predicted with theoretical models. Bottom currents observed in the dumpsites were strong enough for sediment re-suspension, and contributed to the transport of polluted sediments. Diversity and density of the faunal communities were poor at the dumping sites in comparison to the reference area, although the direct effects of CWA on benthos organisms were difficult to determine due to hypoxic or even anoxic conditions near the bottom. Equally, the low oxygen might have affected the biological effects assessed in cod and caged blue mussels. Nonetheless, both species showed significantly elevated molecular and cellular level responses at contaminated sites compared to reference sites.

  • 291. Beldring, Stein
    et al.
    Gottschalk, Lars
    Rodhe, Allan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Tallaksen, Lena M.
    Kinematic wave approximations to hillslope hydrological processes in tills2000In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 14, no 4, p. 727-745Article in journal (Refereed)
    Abstract [en]

    This work has been carried out within the framework of NOPEX - a NOrthern hemisphere climate Processes land surface EXperiment. Its purpose is to describe the spatial variability of groundwater levels and soil moisture content and their influence on runoff generation in small catchments in a landscape dominated by boreal forest and till soils, which is characteristic for the Nordic countries. Kinematic wave approximations have been used to describe saturated subsurface flow and saturation overland flow in hillslopes with a thin soil layer overlying a relatively impermeable bedrock. Simultaneous analyses of catchment runoff, groundwater-table depths and soil moisture in the unsaturated zone have been performed by including the kinematic wave descriptions in a precipitation-runoff model. The results have been compared with observed hydrographs and spatial patterns of groundwater levels and soil moisture content in two small experimental catchments. Results from this study indicate that is reasonable to apply the same parameter set when describing hydrological processes in computational elements with similar characteristics at a scale of about 1 km(2) in the NOPEX area. 

  • 292.
    Beldring, Stein
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Rodhe, Allan
    Tallaksen, Lena
    Kinematic wave approximations to hillslope hydrological processes in till soils2000In: Hydrological Processes, Vol. 14, p. 727-745Article in journal (Refereed)
  • 293.
    Belkin, Igor
    et al.
    Zhejiang Ocean University, Zhoushan, China.
    Andersson, Per
    Swedish Museum of Natural History, Research Division. Naturhistoriska riksmuseet.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    On the discovery of ferromanganese nodules in the world ocean2021In: Deep Sea Research Part I: Oceanographic Research Papers, ISSN 0967-0637, E-ISSN 1879-0119, Vol. 175Article in journal (Refereed)
    Abstract [en]

    For a century, the discovery of ferromanganese (Fe–Mn) nodules in the World Ocean was universally and indisputably credited to the Challenger circum-global oceanographic expedition of 1872–1876, during which the first manganese nodules and crusts were dredged up from the sea floor in February–March 1873. A century later, a counterclaim appeared in the literature, crediting Nordenskiöld’s expedition on Sofia in 1868, five years before the Challenger findings, for the discovery of Fe–Mn nodules in the ocean. This counterclaim, widely accepted without scrutiny, was based on the Gustaf Lindström (1884) chemical analysis of a single bottom sediment sample among 14 samples from two Arctic expeditions led by Nordenskiöld:Sofia 1868 and Vega 1878–1880. The Lindström (1884) report published as an eight-page brochure in Swedish remained almost unknown to the research community until now. A close examination of this report and other historical evidence revealed that the counterclaim of discovery by the Sofia 1868 expedition to the Kara Sea is invalid based on three notable facts: (1) Sofia never sailed in the Kara Sea; (2) the single bottom sediment sample with an extremely high content of Mn (24%), was collected in the Kara Sea during the Vega Expedition across the Northeast Passage; (3) the Vega sampling was in 1878, not in 1868. Meanwhile, five and a half years prior to the Vega sampling, the first Fe–Mn nodules and crusts were dredged up from the sea floor on 18 February and March 7, 1873 during the Challenger expedition. These findings have been promptly reported and published in May 1873. Thus, the credit for the discovery of ferromanganese nodules in the World Ocean firmly belongs to the Challenger expedition.

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  • 294. Beltran, Catherine
    et al.
    Rousselle, Gabrielle
    Backman, Jan
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Wade, Bridget S.
    Sicre, Marie Alexandrine
    Paleoenvironmental conditions for the development of calcareous nannofossil acme during the late Miocene in the eastern equatorial Pacific2014In: Paleoceanography, ISSN 0883-8305, E-ISSN 1944-9186, Vol. 29, no 3, p. 210-222Article in journal (Refereed)
    Abstract [en]

    Repeated monospecific coccolithophore dominance intervals (acmes) of specimens belonging to the Noelaerhabdaceae familyincluding the genus Reticulofenestra and modern descendants Emiliania and Gephyrocapsaoccurred during the Neogene. Such acme was recognized during the late Miocene (similar to 8.6Ma), at a time of a major reorganization of nannofossil assemblages resulting in a worldwide temporary disappearance of larger forms of the genus Reticulofenestra (R. pseudoumbilicus) and the gradual recovery and dominance of its smaller forms (< 5 mu m). In this study we present a multiproxy investigation of late Miocene sediments from the east equatorial Pacific Integrated Ocean Drilling Program Site U1338 where small reticulofenestrid-type placoliths with a closed central areaknown as small Dictyococcites spp. (< 3 mu m)formed an acme. We report on oxygen and carbon stable isotope records of multispecies planktic calcite and alkenone-derived sea surface temperature. Our data indicate that, during this 100 kyr long acme, the east equatorial Pacific thermocline remained deep and stable. Local surface stratification state fails to explain this acme and thus contradicts the model-based hypothesis of a Southern Ocean high-latitude nutrient control of the surface waters in the east equatorial Pacific. Instead, our findings suggest that external forcing such as an extended period of low eccentricity may have created favorable conditions for the small Dictyococcites spp. growth. Key Points < list list-type=bulleted id=palo20081-list-0001> < list-item id=palo20081-li-0001> EEP thermocline deep during the late Miocene small Dictyococcites acme <list-item id=palo20081-li-0002>Low eccentricity favorable for the small Dictyococcites spp. growth

  • 295.
    Beltrán-Abaunza, José M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Remote sensing in optically complex waters: water quality assessment using MERIS data2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This PhD study focusses on the use of MEdium Resolution Imaging Spectrometer (MERIS) data for reliable and quantitative water-quality assessment of optically-complex waters (lake, brackish and coastal waters). The thesis is divided into two parts: A. intercalibration of reflectance measurements in different optically-complex water bodies (Paper I), and validation of various satellite processing algorithms for the coastal zone (Paper II). B. Applications: the use of MERIS data in integrated coastal zone management mostly using Himmerfjärden bay as an example.

    Himmerfjärden bay is one of the most frequently monitored coastal areas in the world and it is also the recipient of a large urban sewage treatment plant, where a number of full-scale nutrient management experiments have been conducted to evaluate the ecological changes due to changes in nutrient schemes in the sewage plant.

    Paper I describes the development and assessment of a new hyperspectral handheld radiometer for in situ sampling and validation of remote sensing reflectance.  The instrument is assessed in comparison with readily available radiometers that are commonly used in validation.

    Paper II has a focus on the validation of level 2 reflectance and water products derived from MERIS data. It highlights the importance of calibration and validation activities, and the current accuracy and limitations of satellite products in the coastal zone.  Bio-optical in situ data is highlighted as one of the key components for assessing the reliability of current and future satellite missions. Besides suspended particulate matter (SPM), the standard MERIS products have shown to be insufficient to assure data quality retrieval for Baltic Sea waters. Alternative processors and methods such as those assessed and developed in this thesis therefore will have to be put in place in order to secure the success of future operational missions, such as Sentinel-3.

    The two presented manuscripts in the applied part B of the thesis (paper III and IV), showed examples on the combined use of in situ measurements with optical remote sensing to support water quality monitoring programs by using turbidity and suspended particulate matter as coastal indicators (manuscript III). The article also provides  a new turbidity algorithm for the Baltic Sea and a robust and cost-efficient method for research and management.  A novel approach to improve the quality of the satellite-derived products in the coastal zone was demonstrated in manuscript IV. The analysis included, the correction for adjacency effects from land and an improved pixel quality screening.  The thesis provides the first detailed spatio-temporal description of the evolution of phytoplankton blooms in Himmerfjärden bay  using quality-assured MERIS data, thus forwarding our understanding of ecological processes in in Swedish coastal waters.

    It must be noted that monitoring from space is not a trivial matter in these optically-complex waters dominated by the absorption of coloured dissolved organic matter (CDOM). These types of coastal waters are especially challenging for quantitative assessment from space due to their low reflectance.  Papers III and IV thus also provide tools for a more versatile use in other coastal waters that are not as optically-complex as the highly absorbing Baltic Sea waters. The benefits of the increased spatial-temporal data coverage by optical remote sensing were presented, and also compared to in situ sampling methods (using chlorophyll-a as indicator).

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  • 296.
    Beltrán-Abaunza, José M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Uncertainty measurements and validation of ocean colour data in optically complex waters2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis addresses validation activities associated with the use of in situ and satellite-based radiometers to assess water quality parameters, such as chlorophyll-a (Chl-a), total suspended matter (TSM) and coloured dissolved organic matter (CDOM- also known as yellow substances, YEL) in CDOM-dominated waters. In paper I, an inter-comparison of in situ radiometers is presented. Here, a new hand-held radiometer, the Water Insight Spectrometer (WISP-3) was tested and evaluated for routine water monitoring against other common radiometers used for validation. The WISP-3 measures the reflectance at the surface, and thus also works in shallow depths. The WISP-3 is designed for validation in places where other radiometers are difficult to deploy. As it is hyperspectral it can be used to develop in-water algorithms for the retrieval of water-quality information. In paper II, satellite data from the 3rd reprocessing archives of the MEdium Resolution Imaging Spectrometer (MERIS) sensor on board of ENVISAT is evaluated. MERIS level 2 reflectance and water products are assessed against in situ data. This assessment is required in order to ensure the reliability of  monitoring systems based on MERIS data such as the Swedish coastal and lake monitoring system www.vattenkvalitet.se. The evaluation of reflectance data is based on a pair-wise comparison of the standard MEGS processor and three coastal processors that are provided as source free plug-ins for the VISAT BEAM software; all pairs are compared to data measured in situ. The derived water products are evaluated both on a pair-wise comparison of processors as well as on an individual comparison of some processors to sea-truthing data. The studied processors improved the retrievals of MERIS reflectance when used the latest MERIS FR 3rd reprocessing, equalized and “smile” corrected and a land adjacency effects were corrected using the improved contrast between ocean and land (ICOL). The blue spectral bands remain problematic for all processors. Chlorophyll was retrieved best using FUB with an overestimation between 18% - 26.5% (MNB) dependent on the compared pairs. At low chlorophyll < 2.5 mg m-3, random errors dominates the retrievals of MEGS. MEGS showed lower bias and random errors when deriving suspended particulate matter (SPM) with an overestimation in the range 8-16% (MNB). All processors failed to retrieve CDOM correctly, but FUB could at least resolve variations in CDOM, however with a systematic underestimation that may be corrected for by using a local correction factor . MEGS has shown already potential to be used as operational processor in the Himmerfjärden bay and adjacent areas, but it requires further improvement of the atmospheric correction for the blue bands and better definition at relatively low chlorophyll concentrations in presence of CDOM.

  • 297.
    Beltrán-Abaunza, José M.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kratzer, Susanne
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hoglander, Helena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Using MERIS data to assess the spatial and temporal variability of phytoplankton in coastal areas2017In: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 38, no 7, p. 2004-2028Article in journal (Refereed)
    Abstract [en]

    This study aims to highlight how satellite data can be used for an improved understanding of ecological processes in a narrow coastal bay. The usefulness of the Medium Resolution Imaging Spectrometer (MERIS) data (2003-2011) as a complement to the in situ monitoring in Himmerferdenn (HF) bay is used as an example that can also be applied to other coastal areas. HF bay is one of the most frequently monitored coastal areas in the world, allowing for a rigorous comparison between satellites and ship-based monitoring data. MERIS data was used for the integration of chlorophyll-a (chl-a) over each waterbody in the HF area, following the national waterbody classification by the Swedish Meteorological and Hydrological Institute (SMHI). Chl-a anomaly maps were produced for the bay and its adjacent areas. The maps could be used to show events with high chl-a, both with natural causes (e.g. a Prymnesium polylepis bloom observed in summer 2008) and of anthropogenic causes (e.g. failure in the local sewage treatment plant resulting in a strong spring bloom in 2006). Anomaly maps thereby allow to scan larger coastal stretches to discriminate areas that may require additional sampling by ship, or to identify areas that do not differ much from the median value of the MERIS time series.

  • 298. Bemmoussat, A.
    et al.
    Korichi, K.
    Baahmed, D.
    Maref, N.
    Djoukbala, O.
    Kalantari, Zahra
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Department of Physical Geography, Stockholm University, Stockholm, Sweden..
    Bateni, S. M.
    Contribution of Satellite-Based Precipitation in Hydrological Rainfall–Runoff Modeling: Case Study of the Hammam Boughrara Region in Algeria2021In: Earth Systems and Environment, ISSN 2509-9426, Vol. 5, no 4, p. 873-881Article in journal (Refereed)
    Abstract [en]

    Hydrological models are viewed as powerful tools that have a major importance for managing water resources and predicting flows. It should be specified that the meteorological parameter rainfall is the main input in these models. In the current study, data from only one rainfall station are available over the analysis domain, which cannot represent the entire Hammam Boughrara watershed of Algeria. The precipitation data remotely detected by the tropical rainfall measuring mission (TRMM) provide good spatial coverage in the watershed and can be used to fill in the missing data. The use of raw TRMM data gives poor results from the simulated flow rates with a Nash–Sutcliffe efficiency NSE equal to 0.34 for the validation period that ranges from year 2000 to 2005; this is mainly due to uncertainties in the TRMM data. For this reason, it was deemed necessary to carry out a performance test of the model. The results obtained give an unsatisfactory percent bias (PBIAS) of − 46.24%, which suggests the need to perform a correction to decrease the PBIAS of satellite precipitation. For this, two methods were used: the linear regression method and the multiplicative method. These two techniques can only be applied if there is at least one rainfall measurement station available in the watershed. The obtained results are very satisfactory since the PBIAS reaches − 0.62% for the linear regression method and − 11.58% for the multiplicative method. In addition, the use of corrected TRMMs gives also very good results with a Nash–Sutcliffe efficiency that ranges from 0.74 to 0.88 for both validation and calibration periods. Overall, the current study is supportive to estimate the satellite-based rainfall, one of the very sensitive to measure the meteorological parameter, in northwestern Algeria.

  • 299.
    Bender, Anke
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Langhamer, Olivia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Francisco, Francisco
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Forslund, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Hammar, Linus
    Octopus Ink Research & Analysis, Lysekil, Sweden.
    Sundberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Molander, Sverker
    Chalmers University of Technology, Gothenburg, Sweden.
    Imaging-sonar observations of salmonid interactions with a vertical axis instream turbine2023In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467Article in journal (Refereed)
    Abstract [en]

    Anthropogenic activities and their influences on aquatic systems is an important topic, especially considering the growing interest in using the earth's resources in a sustainable way. One of those anthropogenic activities is the introduction of renewable technologies into the aquatic environment such as instream turbines. Environmental studies around those technologies are often still ongoing due to their novelty. During the spring of 2018, juvenile individuals of two salmonid species, Atlantic salmon and brown trout were released upstream a vertical axis instream turbine in the river Dal (Dalälven) in eastern Sweden. The aim of this study was to investigate the swimming behavior of the salmonids around a small-scale prototype vertical axis instream turbine. The swimming pattern and the possible response of avoiding the vertical axis instream turbine were documented with a multi beam sonar. A control area, next to the turbine, was used as reference. No consistent results were shown for trout as they were passing the control area with a statistically high variation, and specimens were rarely observed in proximity of the turbine, neither if the turbine was operating nor at stand still. Salmon clearly avoided the operating turbine, but did not avoid the turbine when it was at stand still, and was often observed swimming straight through the turbine area. These findings indicate that operating this type of instream turbine in a river affects the swimming behavior of Atlantic salmon but is unlikely to affect its migration paths. For brown trout, the statistical results are inconclusive, although data indicate a response of avoiding the turbine. The species are in little risk to suffer physical harm as no fish entered the rotating turbine, despite very turbid water conditions.

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  • 300.
    Bengtsson, L.
    Luleå University of Technology.
    Wind Induced Circulation In Lakes1978In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 9, no 2, p. 75-94Article in journal (Refereed)
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