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  • 1. Ahmed, Engy
    et al.
    Hugerth, Luisa W.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Logue, Jürg Brendan
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Bruchert, Volker
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Holmström, Sara J. M.
    Mineral Type Structures Soil Microbial Communities2017Inngår i: Geomicrobiology Journal, ISSN 0149-0451, E-ISSN 1521-0529, Vol. 34, nr 6, 538-545 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soil microorganisms living in close contact with minerals play key roles in the biogeochemical cycling of elements, soil formation, and plant nutrition. Yet, the composition of microbial communities inhabiting the mineralosphere (i.e., the soil surrounding minerals) is poorly understood. Here, we explored the composition of soil microbial communities associated with different types of minerals in various soil horizons. To this effect, a field experiment was set up in which mineral specimens of apatite, biotite, and oligoclase were buried in the organic, eluvial, and upper illuvial horizons of a podzol soil. After an incubation period of two years, the soil attached to the mineral surfaces was collected, and microbial communities were analyzed by means of Illumina MiSeq sequencing of the 16S (prokaryotic) and 18S (eukaryotic) ribosomal RNA genes. We found that both composition and diversity of bacterial, archaeal, and fungal communities varied across the different mineral surfaces, and that mineral type had a greater influence on structuring microbial assemblages than soil horizon. Thus, our findings emphasize the importance of mineral surfaces as ecological niches in soils.

  • 2.
    Alakukku, Laura
    University of Helsinki, Finland.
    28 Soil Compaction2012Inngår i: Sustainable Agriculture / [ed] Christine Jakobsson, Uppsala: Baltic University Press , 2012, 1500, 217-221 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 3.
    Alsterhag, Elin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Förslag till modell av kemikaliespridning i mark anpassad för användning vid räddningsinsats - Kemspill Mark 4.02005Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    After emergencies involving chemical spills it is of great importance that correct measures are taken with short notice, both for the security of people and in order to minimize future environmental consequences. The RIB-unit at the Swedish Rescue Services Agency initiated this study, the aim of which is to propose changes to the existing chemical transport calculation tool: Chemical Spill 3.4, included in RIB - Integrated Decision Support for Civil Protection, so that it can be used for decision support as well as in preventive work. A rough estimation of chemical transport in the subsurface is considered being of great importance when making decisions during emergency response operations.

    The proposition presented in this report is a non site specific chemical transport model which is designed to give a rough estimation of NAPL flow in homogenous isotropic soil shortly after an instantaneous release. The model can be used at two levels; both in situations without access to information on subsurface properties, and with more accuracy in situations with knowledge of the included parameters. For that reason the user can choose among predefined alternatives or assign the parameters a numeric value to increase the quality of the model output. The predefined alternatives are represented by default values for different parameters in the model.

    Suggested model output are vertical and horizontal transport of NAPL phase, horizontal transport of dissolved chemical in the aqueous phase, as well as the amounts of spill that are evaporated and entrapped in the soil, all at the time specified by the user. Moreover the maximum transport of the chemical phase and time to groundwater pollution are given. To make the uncertainty of the model clear for the user the results are given as the most likely value together with the smallest and largest values that can be expected.

    Equations presented in this report describe a selection of subsurface processes which occur after a release of chemicals. The selection is made with the aim to reach satisfying result when the model is used within its domain without making the model complicated for the user. Therefore simplifying assumptions have been made in the descriptions of some processes while some other processes are neglected. Simplifications have been based on recognized references or on theoretical arguments, but the overall performance of the model as well as some of the default input parameters need to be further tested and validated before the new version of the model can be included in RIB. However, compared with the existing version Chemical Spill 3.4 several changes have been suggested; including additional processes, development of default values and making model uncertainty clear to the user. These changes are thought to significantly improve the existing model.

  • 4.
    Arnebrant, Kriatina
    et al.
    Department of Microbial Ecology, University of Lund, Lund, Sweden.
    Schnürer, Johan
    Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Changes in atp content during and after chloroform fumigation1990Inngår i: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 22, nr 6, 875-877 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 5. Arp, Hans Peter H.
    et al.
    Lundstedt, Staffan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Josefsson, Sarah
    Cornelissen, Gerard
    Enell, Anja
    Allard, Ann-Sofie
    Kleja, Dan Berggren
    Native Oxy-PAHs, N-PACs, and PAHs in historically contaminated soils from Sweden, Belgium, and France: their soil-porewater partitioning behavior, bioaccumulation in Enchytraeus crypticus, and bioavailability2014Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, nr 19, 11187-11195 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soil quality standards are based on partitioning and toxicity data for laboratory-spiked reference soils, instead of real world, historically contaminated soils, which would be more representative. Here 21 diverse historically contaminated soils from Sweden, Belgium, and France were obtained, and the soil-porewater partitioning along with the bioaccumulation in exposed worms (Enchytraeus crypticus) of native polycyclic aromatic compounds (PACs) were quantified. The native PACs investigated were polycyclic aromatic hydrocarbons (PAHs) and, for the first time to be included in such a study, oxygenated-PAHs (oxy-PAHs) and nitrogen containing heterocyclic PACs (N-PACs). The passive sampler polyoxymethylene (POM) was used to measure the equilibrium freely dissolved porewater concentration, C-pw, of all PACs. The obtained organic carbon normalized partitioning coefficients, K-TOC, show that sorption of these native PACs is much stronger than observed in laboratory-spiked soils (typically by factors 10 to 100), which has been reported previously for PAHs but here for the first time for oxy-PAHs and N-PACs. A recently developed K-TOC model for historically contaminated sediments predicted the 597 unique, native K-TOC values in this study within a factor 30 for 100% of the data and a factor 3 for 58% of the data, without calibration. This model assumes that TOC in pyrogenic-impacted areas sorbs similarly to coal tar, rather than octanol as typically assumed. Black carbon (BC) inclusive partitioning models exhibited substantially poorer performance. Regarding bioaccumulation, C-pw combined with liposome-water partition coefficients corresponded better with measured worm lipid concentrations, C-lipid (within a factor 10 for 85% of all PACs and soils), than C-pw combined with octanol-water partition coefficients (within a factor 10 for 76% of all PACs and soils). E. crypticus mortality and reproducibility were also quantified. No enhanced mortality was observed in the 21 historically contaminated soils despite expectations from PAH spiked reference soils. Worm reproducibility weakly correlated to C-lipid of PACs, though the contributing influence of metal concentrations and soil texture could not be taken into account. The good agreement of POM-derived C-pw with independent soil and lipid partitioning models further supports that soil risk assessments would improve by accounting for bioavailability. Strategies for including bioavailability in soil risk assessment are presented.

  • 6.
    Arvidsson, Johan
    et al.
    Swedish University of Agricultural Sciences.
    Etana, Ararso
    Swedish University of Agricultural Sciences.
    Myrbeck, Åsa
    Swedish University of Agricultural Sciences.
    Rydberg, Tomas
    Swedish University of Agricultural Sciences.
    29 Ploughless Tillage  in Long- and Short-term  Experiments2012Inngår i: Sustainable Agriculture / [ed] Christine Jakobsson, Uppsala: Baltic University Press , 2012, 1500, 222-228 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 7. Baken, S.
    et al.
    Larsson, M. A.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    Cubadda, F.
    Smolders, E.
    Ageing of vanadium in soils and consequences for bioavailability2012Inngår i: European Journal of Soil Science, ISSN 1351-0754, E-ISSN 1365-2389, Vol. 63, nr 6, 839-847 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Total vanadium (V) concentrations in soils commonly range from 20 to 120 mg kg-1. Vanadium added directly to soils is more soluble than geogenic V and can be phytotoxic at doses within this range of background concentrations. However, it is unknown how slow sorption reactions change the fate and effect of added V in soils. This study addresses the changes in V solubility, toxicity and bioavailability in soils over time. Four soils were amended with pentavalent V in the form of a soluble vanadate salt, and extractable V concentrations were monitored over 100 days. The toxicity to barley and tomato plants was evaluated in freshly spiked soils and in the corresponding aged soils that were equilibrated for up to 330 days after spiking. The V concentrations in 0.01 m CaCl2 soil extracts decreased approximately two-fold between 14 and 100 days after soil spiking, and the reaction kinetics were similar for all soils. The phytotoxicity of added V decreased on average two-fold between freshly spiked and aged soils. The reduced toxicity was associated with a corresponding decrease in V concentrations in the isolated soil solutions and in the shoots. The V speciation in the soil solution of the aged soils was dominated by V(V); less than 8% was present as V(IV). Oxalate extractions suggest that the V(V) added to soils is predominantly sorbed onto poorly crystalline oxyhydroxides. It is concluded that the toxicity of V measured in freshly spiked soils may not be representative of soils subject to a long-term V contamination in the field.

  • 8.
    Bandau, Franziska
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Importance of tannins for responses of aspen to anthropogenic nitrogen enrichment2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Boreal forests are often strongly nitrogen (N) limited. However, human activities are leading to increased N inputs into these ecosystems, through atmospheric N deposition and forest fertilization. N input into boreal forests can promote net primary productivity, increase herbivore and pathogen damage, and shift plant species composition and community structure. Genetic diversity has been suggested as a key mechanism to promote a plant species’ stability within communities in response to environmental change. Within any plant population, specific traits (e.g. growth and defense traits) can vary substantially among individuals, and a greater variation in traits may increase chances for the persistence of at least some individuals of a population, when environmental conditions change. One aspect of plant chemistry that can greatly vary among different genotypes (GTs) are condensed tannin (CTs). These secondary metabolites have been suggested to affect plant performance in many ways, e.g. through influencing plant growth, the interactions of plants with herbivores and pathogens, and through affecting litter decomposition, and hence the return of nutrients to plants. To investigate how genotypic variation in foliar CT production may mediate the effects that anthropogenic N enrichment can have on plant performance and litter decomposition, I performed a series of experiments. For these experiments, aspen (Populus tremula) GTs with contrasting abilities to produce foliar CTs (i.e. low- vs. high-tannin producers) were grown under 3 N conditions, representing ambient N (+0 kg ha-1), upper level atmospheric N deposition (+15 kg ha-1), and forest fertilization rates (+150 kg ha-1). This general experimental set-up was once established in a field-like environment, from which natural enemies were excluded, and once in a field, in which enemies were present. In my first two studies, I investigated tissue chemistry and plant performance in both environments. I observed that foliar CT levels decreased in response to N in the enemy‑free environment (study I), but increased with added N when enemies were present (study II). These opposing responses to N may be explained by differences in soil N availability in the two environments, or by induction of CTs after enemy attack. Enemy damage generally increased in response to N, and was higher in low-tannin than in high-tannin plants across all N levels. Plant growth of high‑tannin plants was restricted under ambient and low N conditions, probably due to a trade-off between growth and defense. This growth constraint for high‑tannin plants was weakened, when high amounts of N were added (study I and II), and when enemy levels were sufficiently high, so that benefits gained through defense could outweigh the costs of defense production (study II). Despite those general responses of low- and high‑tannin producers to added N, I also observed a number of individual responses of GTs to N addition, which in some case were not connected to the intrinsic ability of the GTs to produce foliar CTs. In study III, gene expression levels in young leaves and phenolic pools of the plants that were grown in the enemy‑free environment were studied. This study revealed that gene control over the regulation of the phenylpropanoid pathway (PPP) was distributed across the entire pathway. Moreover, PPP gene expression was higher in high-tannin GTs than in low‑tannin GTs, particularly under ambient N. At the low N level, gene expressions declined for both low- and high-tannin producers, whereas at the high N level expression at the beginning and the end of the PPP was upregulated and difference between tannin groups disappeared. Furthermore, this study showed that phenolic pools were frequently uncorrelated, and that phenolic pools were only to some extent related to tannin production and gene expression. In study IV, I investigated the decomposability of litter from the field plants. I found that N enrichment generally decreased mass loss, but there was substantial genetic variation in decomposition rates, and GTs were differentially responsive to added N. Study IV further showed that CTs only had a weak effect on decomposition, and other traits, such as specific leaf area and the lignin:N ratio, could better explain genotypic difference in mass loss. Furthermore, N addition caused a shift in which traits most strongly influenced decomposition rates. Collectively, the result of these studies highlight the importance of genetic diversity to promote the stability of species in environments that experience anthropogenic change.

  • 9.
    Beckman, Marie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Kvävestatus och risk för nitrifikation i två avverkade skogsområden i Halland2005Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nitrogen deposition leads to environmental damage in areas where the nitrogen deposition is high. Southwest Sweden receives an annual nitrogen deposition of up to 20 kg N/ha. Nitrogen that is not assimilated by the vegetation is accumulated in the soil, which may lead to nitrogen saturation and an elevated risk of nitrogen leaching. Nitrogen leaching from forest areas in southern Sweden has proven to be higher than from agricultural areas, which have been thought to be the main contributors to elevated nitrogen levels in rivers and lakes. The amount of nitrogen that leaches depends on the fraction of the total nitrogen in the soil that consists of nitrate, since nitrate is easily transported through the soil. Nitrogen leaching increases after clear-cutting since the uptake by vegetation is greatly reduced.

    In this study the soil chemistry of two clear-cut spruce stands in Halland, in southwest Sweden, has been analyzed. A previous study in these areas has indicated higher nitrate concentrations in the groundwater in one of the areas and thus a greater nitrogen leaching. Nitrogen deposition in the two areas is estimated to be the same and therefore the soil chemistry has been analyzed to evaluate if differences in the soil can have resulted in differences in the nitrate concentration in the groundwater. The hypothesis is that the area with higher nitrate concentrations in the groundwater has properties more favorable for nitrification, which would be especially apparent in a lower carbon to nitrogen ratio. The pH and storage of nitrate, ammonium, total carbon, total nitrogen and exchangeable cations was analyzed in soil samples from both areas. In addition, a study of stand properties and previous use of the areas was made.

    The analyses performed in this study indicate that the soil properties could not explain the differences in nitrate concentration in the groundwater. The differences found between the areas were that the area with lower nitrate concentrations in the groundwater had higher nitrate and ammonium concentrations and higher pH in the soil. The reason for this might be that the soil in this area has larger capacity to bind elements. The fact that the soil samples were sampled during different seasons probably had a major effect on these results. The history and stand properties of the two areas were similar. According to site index one area was more fertile, which benefits nitrification. This fact was not confirmed by the analyses, but it probably caused the nitrification rate to be higher in this area.

  • 10.
    Berg, Björn
    et al.
    Dipartimento biologia strutturale e funzionale, Complesso universitario di Monte S. Angelo, Napoli, Italy; Department of forest ecology, University of Helsinki, Helsinki, Finland.
    Davey, M. P.
    Department of plant sciences, University of Cambridge, Cambridge, United Kingdom.
    De Marco, A.
    Dipartimento biologia strutturale e funzionale, Complesso universitario di Monte S. Angelo, Napoli, Italy.
    Emmett, B
    Centre for ecology and hydrology, Bangor.
    Faituri, M.
    Department of soils and water, Omar AlMukhtar university, Elbeida, Libyan Arab Jamahiriya.
    Hobbie, S. E.
    Department of ecology, evolution and behavior, University of Minnesota, St. Paul, USA.
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Liu, C.
    Department of landscape science and engineering, College of agriculture and biology, Shanghai, ChinaShanghai Jiao Tong university,.
    McClaugherty, C.
    Department of biology, Mount Union college, Alliance, USA.
    Norell, L.
    Unit of applied statistics and mathematics, SLU, Uppsala, Sweden.
    Rutigliano, F. A.
    Dipartimento di scienze ambientali, Seconda Università degli studi di Napoli, Caserta, Italy.
    Vesterdal, L.
    Forest & landscape Denmark, University of Copenhagen, Hørsholm, Denmark.
    Virzo De Santo, A.
    Dipartimento biologia strutturale e funzionale, Complesso universitario de Monte S. Angelo, Napoli, Italy.
    Factors influencing limit values for pine needle litter decomposition: A synthesis for boreal and temperate pine forest systems2010Inngår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 100, nr 1, 57-73 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We synthesized available data for decomposition of pine (Pinus) needle litter in pine forests to determine the litter chemical characteristics and climate factors that explained variation in the limit value, i. e. the level of accumulated mass loss at which the decomposition process either continues at a very low rate or possibly stops. Our data base included 56 separate studies on decomposition of pine needle litter, spanning Scots pine, lodgepole pine, Aleppo pine, stone pine and white pine, mainly incubated at the site of collection. Studies had 5 to 19 samplings, on average 10, and the decomposition was followed to a mass loss ranging from 47 to 83%, on average 67%. The periods from 3.0 to 5.4 years, on average 3.9 years, were of sufficient duration to allow estimates of limit values of decomposition. We used a linear mixed model with regression effects to relate limit values to potential explanatory variables, namely the sites' long-term mean annual temperature (MAT) and mean annual precipitation (MAP) and to substrate-chemistry factors. Regarding the latter, we explored two models; one that included initial concentrations of water solubles, lignin, N, P, K, Ca, Mg, and Mn and one that included only lignin, N, Ca, and Mn to focus on those nutrients known to influence lignin degradation. Using backward elimination significant explanatory variables were determined. For litter decomposed in its site of origin we found the limit value to depend mainly on the initial concentration of Mn, with higher Mn concentrations resulting in higher accumulated mass loss. Thus, litter with higher Mn reached a higher limit value and left a smaller stable fraction. This is likely due to the fact that Mn is an essential component of ligninolytic enzymes important for degrading litter in the later stages of decomposition. Manganese has received little attention in decomposition studies to date. Given its significance in this synthesis, the role of Mn in influencing variation in the late stages of decomposition among ecosystems and among litters of other genera besides Pinus deserves further attention.

  • 11.
    Berg, Björn
    et al.
    Department of Forest Sciences, University of Helsinki, Helsinki, Finland .
    Erhagen, Björn
    Department of Ecology and Environmental Sciences, University of Umeå, Umeå, Sweden .
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Nilsson, Mats
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå.
    Stendahl, Johan
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala.
    Trum, Florence
    Earth and Life Institute, Universite' catolique de Louvain, Louvain-la-Neuve, Belgium .
    Vesterdal, Lars
    Department of Geosciences and Natural Resource Management, University of Copenhagen, Fredriksberg C, Denmark .
    Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems: a review2015Inngår i: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 358, 248-260 s., 15021Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7mgg-1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT.Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter’s Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p<. 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO<inf>2</inf>) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase.

  • 12.
    Berg, Björn
    et al.
    Department of Forest Ecology, University of Helsinki, Helsinki, Finlan; Dipartimento Biologia Strutturale e Funzionale, Complesso Universitario, Napoli, Italy.
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Nilsson, Åke
    Department of Forest Soils, Swedish University of Agriculture, Uppsala, Sweden.
    Gundersen, Per
    Forest and Landscape Denmark, University of Copenhagen, HØrsholm, Denmark.
    Norell, Lennart
    Unit of Applied Statistics and Mathematics, Swedish University of Agrictulture, Uppsala, Sweden.
    Sequestration of carbon in the humus layer of Swedish forests - direct measurements2009Inngår i: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 39, nr 5, 962-975 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To determine sequestration rates of carbon dioxide (CO2) we calculated the carbon (C) storage rate in humus layers of Swedish forests with Podsolic soils, which account for 14.2 x 106 ha of the 22.7 x 106 ha of forested land in Sweden. Our data set covered 41 years of humus inventories and mean humus layer thickness in 82513 plots. We analysed three forest types: (i) all combinations of tree species, (ii) forests dominated (>70%) by Norway spruce (Picea abies (L.) Karst.), and (Ui) forests dominated (>70%) by Scots pine (Pinus sylvestris L.). To relate changes in humus layer thickness to land area we used the intersections in 25 km x 25 km grids and used kriging interpolation, permitting calculations for each forest type. For each intersection mean humus thickness for each year was calculated and regressed against time to obtain the rate of change. This rate, humus bulk density, and humus C concentration were used, to calculate sequestration rates. The mean sequestration rate was 251 kg C-ha-1'year1, which is higher than theoretical values. The sequestration rate was positively related to temperature sum, albeit including effects of forest management. The pine-dominated forest type had a mean rate of 283 kgCha⁁year-1, and. the spruce-dominated had a mean rate of 239 kg Cha-1-year1. Under similar site conditions, pine sequestered more C than spruce (difference of 71 kg Cha-1'year-1; p < 0.0001), showing the importance of this type of ecosystem for C sequestration.

  • 13.
    Blad, Sofia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Torkat bioavfall som jordförbättringsmedel2007Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The main project Dry preservation of source-separated organic household wastes involves a new technique for treatment of biowaste through drying. Investigations are going on to determine how the dried biowaste best can be used to close the natural circular flow of nutrients. The objective of this degree project is to determine if the dried biowaste can be used as a soil conditioner. By restoring the nutrients in the material to the ground, the natural circular flow is closed. A declaration of contents, including the nutrient levels, C/N ratio, pH and the electrical conductivity of the dried biowaste, was constructed and a germination test was done to make sure that the material did not inhibit sprouting. Further on a method was developed to study the decomposition process, and in particular the nitrogen mineralization of the dried biowaste. This method was then used practically.

    The results of this degree project indicate that the decomposition capacity of the dried biowaste is very good. The germination test showed that the material in a diluted form (up to 50 % dried biowaste) did not inhibit sprouting. The examination of the nitrogen mineralization showed a fast liberalisation of nutrients available to plants, with only a shorter period of nitrogen immobilization. Together these results imply that the dried material could function well as a soil conditioner.

  • 14.
    Blume-Werry, Gesche
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Jansson, Roland
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Milbau, Ann
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Biodiversity and Natural Environment, Research Institute for Nature and Forest INBO, Kliniekstraat 25,1070 Brussels, Belgium.
    Root phenology unresponsive to earlier snowmelt despite advanced above-ground phenology in two subarctic plant communities2017Inngår i: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 31, nr 7, 1493-1502 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. Earlier snowmelt at high latitudes advances above-ground plant phenology, thereby affecting water, nutrient and carbon cycles. Despite the key role of fine roots in these ecosystem processes, phenological responses to earlier snowmelt have never been assessed below-ground. 2. We experimentally advanced snowmelt in two contrasting plant community types (heath and meadow) in northern Sweden and measured above- and below-ground phenology (leaf-out, flowering and fine root growth). We expected earlier snowmelt to advance both above- and below-ground phenology, and shrub-dominated heath to be more responsive than meadow. 3. Snow melted on average 9 days earlier in the manipulated plots than in controls, and soil temperatures were on average 0.9 degrees C higher during the snowmelt period of 3 weeks. This resulted in small advances in above-ground phenology, but contrary to our expectations, root phenology was unresponsive, with root growth generally starting before leaf-out. These responses to the snowmelt treatment were similar in both plant community types, despite strong differences in dominating plant functional types and root properties, such as root length and turnover. 4. The lack of a response in root phenology, despite warmer soil temperatures and above-ground phenological advances, adds evidence that above-ground plant responses might not be directly translated to below-ground plant responses, and that our understanding of factors driving below-ground phenology is still limited, although of major importance for water, nutrient and carbon cycling.

  • 15.
    Bonde, Torben A.
    et al.
    Department of Water in Environment and Society, University of Linköping, Linköping, Sweden.
    Schnürer, Johan
    Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Rosswall, Thomas
    Department of Water in Environment and Society, University of Linköping, Linköping, Sweden.
    Microbial biomass as a fraction of potentially mineralizable nitrogen in soils from long-term field experiments1988Inngår i: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 20, nr 4, 447-452 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aerobic long-term incubations (40-wk) were employed to measure the potentially mineralizable nitrogen (N0) in five 30-yr old cropping systems. The cropping systems consisted of: (1) bare fallow; (2) cropping with no additions; (3) cropping with 80 kg N ha-1 y-1 as Ca(NO3)2; (4) cropping with 80 kg N ha-1 yr-1 as Ca(NO3)2 plus 1800kg C ha-1 yr-1 as straw; and (5) cropping with 80 kg N ha-1 yr-1 plus 1800 kg C ha-1 yr-1 as farmyard manure. The amounts of N mineralized during the 40-wk incubations were between 93 and 168 μg g-1 (302-543 kg N ha-1 down to 25cm depth) with the lowest value for the fallow and the highest for the farmyard manure treatment. Microbial biomass-C and -N were measured on four occasions during the incubations. The biomass-C showed a rapid decrease to week 4 (to 36% of the initial mass), a slower decrease to week 9 (to 23% of initial mass) and a very slow decline to the final determination at the end of the incubation (to 8% of initial mass). The biomass-N displayed a similar pattern. Two related models were employed to describe the kinetics of N-mineralization during incubation: (1) a two-component first-order; and (2) a simplified special case of the two-component model. In all cases except the straw-amended soil, the simplified two-component model offered the best description of the curves of accumulated mineral-N. The available fraction, Na, of soil organic-N had mineralization rate constants similar to those for mineralization of microbial biomass.

  • 16.
    Boström, Björn
    et al.
    Örebro universitet, Institutionen för naturvetenskap.
    Comstedt, Daniel
    Örebro universitet, Institutionen för naturvetenskap.
    Ekblad, Alf
    Örebro universitet, Institutionen för naturvetenskap.
    Can isotopic fractionation during respiration explain the 13C-enriched sporocarps of ectomycorrhizal and saprotrophic fungi?2008Inngår i: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 177, nr 4, 1012-1019 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    • The mechanism behind the 13C enrichment of fungi relative to plant materials is unclear and constrains the use of stable isotopes in studies of the carbon cycle in soils.

    • Here, we examined whether isotopic fractionation during respiration contributes to this pattern by comparing δ13C signatures of respired CO2, sporocarps and their associated plant materials, from 16 species of ectomycorrhizal or saprotrophic fungi collected in a Norway spruce forest.

    • The isotopic composition of respired CO2 and sporocarps was positively correlated. The differences in δ13C between CO2 and sporocarps were generally small, < ±1‰ in nine out of 16 species, and the average shift for all investigated species was 0.04‰. However, when fungal groups were analysed separately, three out of six species of ectomycorrhizal basidiomycetes respired 13C-enriched CO2 (up to 1.6‰), whereas three out of five species of polypores respired 13C-depleted CO2 (up to 1.7‰; P < 0.05). The CO2 and sporocarps were always 13C-enriched compared with wood, litter or roots.

    • Loss of 13C-depleted CO2 may have enriched some species in 13C. However, that the CO2 was consistently 13C-enriched compared with plant materials implies that other processes must be found to explain the consistent 13C-enrichment of fungal biomass compared with plant materials.

  • 17.
    Bringmark, Ewa
    et al.
    Department of Aquatic Sciences and Assessment, SLU, Uppsala, Sweden.
    Bringmark, Lage
    Department of Aquatic Sciences and Assessment, SLU, Uppsala, Sweden.
    Sonesten, Lars
    Department of Aquatic Sciences and Assessment, SLU, Uppsala, Sweden .
    Mjöfors, Kristina
    Department of Soil and Environment, SLU, Uppsala, Sweden.
    Johansson, Maj-Britt
    Högskolan i Gävle.
    Long-term monitoring of scots pine litter decomposition rates throughout sweden indicates formation of a more recalcitrant litter in the south2011Inngår i: Ambio, ISSN 0044-7447, Vol. 40, nr 8, 878-890 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Decomposition studies were carried out at sites throughout Sweden, including the four Integrated Monitoring sites. Scots pine needle litterbag weight loss measurements over 3 or 5 years were determined at 26 sites and repeated up to 27 times, depending on the site. Humus layer respiration rates were determined for 20 sites in 1987-1989 and repeated in 2007-2008. Partial Least Squares (PLS) regression was used to elucidate the relative importance of climatic and soil factors. Annual needle weight losses decreased only slowly (20-10%) over 3-5 years for all northern (> 60A degrees N) sites but decreased sharply from 30 to 10% in the third year in southern (< 60A degrees N) sites. Respiration rates of southern sites were less (40% on average) than those of northern sites. Humus layer N was positively correlated to needle weight loss during the first and the second years, but negatively correlated in the third year and to respiration rates. The results indicated that litter formed in southern Sweden became more recalcitrant in later stages of decomposition compared to litter produced in northern Sweden.

  • 18.
    Buckland, Philip I
    et al.
    Umeå universitet, Humanistiska fakulteten, Arkeologi och samiska studier.
    Johan, Olofsson
    Umeå universitet, Humanistiska fakulteten, Arkeologi och samiska studier.
    Engelmark, Roger
    Umeå universitet, Humanistiska fakulteten, Arkeologi och samiska studier.
    SEAD: Strategic Environmental Archaeology Database, planning report2006Rapport (Annet vitenskapelig)
    Abstract [en]

    This document lays out a strategy for the development of SEAD – A Strategic Environmental Archaeology Database, which will facilitate the digitisation and accessibility augmentation of MAL’s existing data from nearly thirty years of work in the fields of archaeology and environmental science. SEAD will also provide a framework for the entry of data from all future research and consultancy work at MAL, and allow guest researchers and external partners to contribute to, and work with the same data. The planned system will be implemented at both local and internet levels, and be designed with an aim towards broadening its scope with external partners in the future. SEAD will be made available online in order to increase the ease of access to environmental archaeology data and encourage an expansion of both the discipline and Sweden’s role in it. This is inline with current EU strategies on enhancing research infrastructure, and providing a greater insight into human-environment interactions for long term planning.

  • 19.
    Cucarella Cabañas, Victor
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Recycling Filter Substrates used for Phosphorus Removal from Wastewater as Soil Amendments2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis studied the viability of recycling filter substrates as soil amendments after being used in on-site systems for phosphorus (P) removal from wastewater. Focus was put on the materials Filtra P and Polonite, which are commercial products used in compact filters in Sweden. A prerequisite for this choice was to review filter materials and P sorption capacity. The filter substrates (Filtra P, Polonite and wollastonite tailings) were recycled from laboratory infiltration columns as soil amendments to a neutral agricultural soil and to an acid meadow soil to study their impacts on soil properties and yield of barley and ryegrass. The amendments tended to improve the yield and showed a liming effect, significantly increasing soil pH and the availability of P. In another experiment, samples of Filtra P and Polonite were equilibrated in batch experiments with the two soils in order to study the P dynamics in the soil-substrate system.  Batch equilibrations confirmed the liming potential of Filtra P and Polonite and showed that improved P availability in soils was strongly dependent on substrate P concentration, phase of sorbed P, and soil type. Finally, samples of Polonite used for household wastewater treatment were recycled as soil amendments to a mountain meadow and to an agricultural field for wheat cropping. The liming effect of Polonite was confirmed under field conditions and the results were similar to those of lime for the mountain meadow soil. However, the results were quite different for the agricultural field, where Polonite did not affect soil pH or any other chemical and physical soil properties investigated and had no impact on wheat yield and quality. The results from field experiments suggested that Polonite can be safely recycled to meadows and cropping fields at rates of 5-10 ton ha-1 but long-term studies are needed to forecast the effects of accumulation.

  • 20.
    Cucarella, Victor
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Zaleski, T.
    Mazurek, R.
    Recycling of calcium-silicate material after wastewater filtration to agriculture -Soil condition impact2012Inngår i: Ecological Chemistry and Engineering S, ISSN 1898-6196, Vol. 19, nr 3, 373-382 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reactive filter materials aimed at phosphorus (P) recovery is a novel method for on-site wastewater treatment. Once the bed filter is no longer effective, the sorbent must be replaced and can then be recycled as a soil amendment to agriculture. This study investigated the short-term effects of such amendments in a field with a wheat crop in order to evaluate the risks and/or potential benefits of this disposal option. The developed product Polonite (manufactured from Opoka) was used as a model filter sorbent in the field trial. Rates corresponding to approximately 6 and 8 tons per hectare were applied. In the short-term, this amending did not affect soil physical and sorption properties. The rate of Polonite used here, as P source for wheat was irrelevant in this kind of soil. The usefulness of this disposal option of exhausted filter material is discussed.

  • 21. De Long, Jonathan R.
    et al.
    Laudon, Hjalmar
    Blume-Werry, Gesche
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Kardol, Paul
    Nematode community resistant to deep soil frost in boreal forest soils2016Inngår i: Pedobiologia, ISSN 0031-4056, E-ISSN 1873-1511, Vol. 59, nr 5-6, 243-251 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As global climate change advances, shifts in winter precipitation are becoming more common in high latitude ecosystems, resulting in less insulating snow cover and deeper soil frost. Long-term alterations to soil frost can impact on ecosystem processes such as decomposition, microbial activity and vegetation dynamics. In this study we utilized the longest running, well-characterized soil frost manipulation experiment in a boreal forest. We measured nematode family composition and feeding group abundances at four different soil layer depths from plots that had been subjected to deep soil frost for one and 11 years. The overall abundance of nematodes and the different feeding groups were unaffected by deep soil frost. However, a higher Maturity Index was weakly associated with deep soil frost (indicative of lower nutrient enrichment and more persister nematode (i.e., K-strategist) families), likely due to the loss of nutrients and reduced inputs from inhibited decomposition. Multivariate and regression analyses showed that most nematode families were weakly associated with dominant understory plant species and strongly associated with soil organic matter (SOM). This is probably the result of higher resource availability in the control plots, which is favorable to the nematode community. These results indicate that the nematode community was more strongly driven by the long-term indirect effects of deep soil frost on SOM as opposed to the direct effects. Our findings highlight that the indirect effects of altered winter precipitation and soil frost patterns may be more important than direct winter climate effects. Further, such indirect effects on SOM and the plant community that may affect the nematode community can only be seen in long-term experiments. Finally, given the critical role nematodes play in soil food webs and carbon and nutrient cycling, our results demonstrate the necessity of considering the response of nematodes to global climate change in boreal forest soils. 

  • 22.
    Dong, Qian
    KTH, Tidigare Institutioner, Materialvetenskap.
    Studies of transport in some oxides by gas phase analysis2004Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 23.
    Earon, Robert
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Olofsson, Bo
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Initial Effects of a New Highway Section on Soil and Groundwater2012Inngår i: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 223, nr 8, 5413-5432 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The environmental impacts of 16 different contaminants originating from the E18 Highway (17,510 annual average daily traffic) were studied over the initial months of the highway's operational life. Investigative methods used included electrical resistivity surveying, water chemistry analyses, soil analyses, distribution modeling, and transportation modeling of contaminants. The study conclusively showed a year-round infiltration due to melting of the snowpack from road salt, and a strong preferential, anthropogenic pathway due to increased hydraulic conductivities of road construction materials relative to in situ soils. The resistivity surveys produced values well below the expected values for the highway materials, indicating increased ionic content within the unsaturated zone. Time lapse resistivity modeling showed a clear downwards spreading of contamination from the roadway to subsurface distances greater than 5 m. Elevated concentrations of nearly every studied contaminant relative to baseline values were observed, with many metal concentrations within the snow pack averaging values in excess of the Swedish Environmental Protection Agency's groundwater limitations. Distribution modeling demonstrated a potential offset of peak values from the road surface due to plowing and splash transport processes, and indicated different distribution behavior during winter months than during summer months. One-dimensional transport modeling demonstrated the importance of adsorption and other retentive factors to the migration of contaminants to groundwater and provided an estimate for potential long-term contaminant concentrations.

  • 24.
    Ed, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Miljöteknisk undersökning enligt MIFO: en studie på fastigheten Bodsjölandet 1:14 avseende den nedlagda tjärfabriken i Grötingen2006Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    During 40 years of industrial production, from the end of the 1890’s until the end of 1930’s, coal and wood distillation products were manufactured in AB Carbo’s tar factory along the River Gimån in Grötingen, in the county of Jämtland, Sweden. In accordance with the Swedish Environmental Protection Agency’s Methods for Inventories of contaminated sites, MIFO, the site in Grötingen has been identified as a potentially contaminated site. In order to determine whether toxic substances pose a threat to human health and ecological systems in the area, there was a need to investigate the presence of contaminants, their levels and potential for migration. Sensitivity and protection value regarding exposure of man and the environment at the site is high, since people live next to the site and River Gimån is a part of the Natura 2000 network.

    The initial phase of the MIFO method includes a preliminary survey. Information regarding AB Carbo’s activities and production has been obtained by studying map and archive material, as well as by interviews and site inspections. Potential point sources have been identified around the factory forge, storage cellar, distillation building and the wooden channel for the discharge of tar and other condensates into the River Gimån.

    Guided by the information gathered in MIFO phase 1, a preliminary site investigation was carried out at the site. It included sampling of soil, sediment, groundwater and surface water together with sample analysis of heavy metals and organic pollutants. The result of the analysis shows that very high levels of the contaminants PAH, aromatics and lead are found in both soil and groundwater. The sediment contamination level is high while that of surface water is very low. The distribution of contamination levels among the samples indicates a likely point source close to the distillation building due to very high contamination levels in soil and groundwater close to that point. The point source may represent a larger spillage or dumped waste products.

    Two of the contaminants present at the site, phenantrene and phenol, were studied by using the model CHEMFLO-2000. The analysis focussed on mobility in unsaturated soils under conditions that prevail at the site in Grötingen. The adsorption of phenantrene is significantly higher in comparison to that of phenol.

    Comprehensive assessment and risk classification results in risk class 2 for the site in Grötingen, which implies a need for further investigations and measurements. The risk of human exposure could be reduced by removing contaminated soil around the factory forge. Additional studies should focus on finding the location of the point source around the distillation building as well as contaminant migration from the wooden channel and the geographical spreading of heavy metal contamination.

  • 25.
    Efremova, Marina
    et al.
    St Petersburg State Agrarian University.
    Izosimova, Alexandra
    Agro-Physical Research Institute, Pushkin.
    35 Contamination of Agricultural Soils with Heavy Metals2012Inngår i: Sustainable Agriculture / [ed] Christine Jakobsson, Uppsala: Baltic University Press , 2012, 1500, 250-252 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 26.
    Efremova, Marina
    et al.
    St Petersburg State Agrarian University, St Petersburg.
    Izosimova, Alexandra
    Agro-Physical Research Institute, Pushkin.
    36 Contamination of Agricultural Soils  with Radionuclides2012Inngår i: Sustainable Agriculture / [ed] Christine Jakobsson, Uppsala: Baltic University Press , 2012, 1500, 253-255 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 27.
    Eidukevičiene, Marija
    Klaipeda University.
    32 Soil Acidification2012Inngår i: Sustainable Agriculture / [ed] Christine Jakobsson, Uppsala: Baltic University Press , 2012, 1500, 239-241 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 28.
    Enfors, Elin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen. Stockholms universitet, Stockholm Resilience Centre.
    Barron, Jennie
    Stockholms universitet, Stockholm Resilience Centre, Stockholm Environment Institute.
    Makurira, Hodson
    University of Zimbabwe.
    Rockström, Johan
    Stockholms universitet, Stockholm Resilience Centre, Stockholm Environment Institute.
    Tumbo, Siza
    Sokoine University of Agriuclture.
    Yield and soil system changes from conservation tillage in dryland farming: A case study from North Eastern Tanzania2011Inngår i: Agricultural Water Management, ISSN 0378-3774, E-ISSN 1873-2283, Vol. 98, nr 11, 1687-1695 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Yield levels in smallholder farming systems in semi-arid sub-Saharan Africa are generally low. Water shortage in the root zone during critical crop development stages is a fundamental constraining factor. While there is ample evidence to show that conservation tillage can promote soil health, it has recently been suggested that the main benefit in semi-arid farming systems may in fact be an in situ water harvesting effect. In this paper we present the result from an on-farm conservation tillage experiment (combining ripping with mulch and manure application) that was carried out in northeastern Tanzania from 2005 to 2008, testing this hypothesis. Special attention was given to the effects on the water retention properties of the soil. The tested conservation treatment only had a clear yield increasing effect during one of the six experimental seasons (maize grain yields increased by 41%, and biomass by 65%), and this was a season that received exceptional amounts of rainfall (549 mm). While the other seasons provided mixed results, there seemed to be an increasing yield gap between the conservation tillage treatment and the control towards the end of the experiment. Regarding soil system changes, small but significant effects on chemical and microbiological properties, but not on physical properties, were observed. This raises questions about the suggested water harvesting effect and its potential to contribute to stabilized yield levels under semi-arid conditions. We conclude that, at least in a shorter time perspective, the tested type of conservation tillage seems to boost productivity during already good seasons, rather than stabilize harvests during poor rainfall seasons. Highlighting the challenges involved in upgrading these farming systems, we discuss the potential contribution of conservation tillage towards improved water availability in the crop root zone in a longer-term perspective.

  • 29.
    Engman, Sven
    Statens väg- och transportforskningsinstitut.
    Bestämning i E-modulapparat av jordmaterials bärighetsegenskaper enligt SEB metoden (Swedish Earth Bearing Method)1973Rapport (Annet vitenskapelig)
    Abstract [sv]

    Vid statens väginstitut, SVI (from 1971-07-01 statens väg och trafikinstitut, VTI), har utvecklats, konstruerats och tillverkats en laboratorieapparat, E-modulapparat modell SVI-51, för belastningsförsök i liten skala och av statisk karaktär. IVE - modulapparaten utsätts framställda prov av jordmaterial för tryck av en cirkulär stålstämpel. Stämpeln kan belastas så, att medeltrycket i kontaktytan med jordprovet blir av inom apparatens belastningsområde (0 - 1 kN) önskad storlek. Normalt åstadskommes med stämpeln tryck, som förekomma eller beräknas uppkomma på 'olika nivåer i en vägs överbyggnad, underbyggnad eller undergrund. När proven belastas observeras genom deformationsmätningar provens elastiska och plastiska uppträdande. Elasticitetsmodulen (E-modulen) för de fram- ställda proven bestäms med ledning av den uppmätta elastiska deformationen. Provens överyta kan förses med s.k. väglast, vars massa kan varieras så att proven per ytenhet erhållerden.be1astning materialet i fält ut- sätts för av ovanpå liggande lager av viss tjocklek, densitet och vattenhalt.

    Med SEB-metoden (Swedish Earth Bearing Method) kan ett jordmaterials elasticitetsmodul och bärighetsegenskaper bestämmas genom belastningsförsök i E-modulapparaten på prov, som vanligen framställts i särskilda cylindrar med volymen 5 000 cm3, s.k. E-modulcylindrar. I cylindrarna packas jordmaterialet med valt arbete vid olika vattenhalter till skrymdensiteter vanligen svarande mot respektive materials densitetskurva enligt någon normerad metod eller till densiteter, som visst material kan påräknas ha, när det ingår som lager i en väg. Enär proven per ytenhet normalt icke utsätts för större belastningar än vad materialet ifråga blir utsatt för i en väg, kan bestämningarna upprepas sedan proven vattenmättats, lagrats på önskat sätt eller torkats. Med ledning av de genom försöken erhållna E-modulerna kan E-modulkurvor eller bärighetskurvor uppdragas för materialet. Bestämningar kan även utföras på med E-modulcylindrar in situ upptagna "ostörda" jordprov.

  • 30.
    Erhagen, Björn
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Swedish Univ Agr Sci SLU, Dept Forest Ecol & Management, S-90183 Umeå, Sweden.
    Ilstedt, Ulrik
    Nilsson, Mats B.
    Temperature sensitivity of heterotrophic soil CO2 production increases with increasing carbon substrate uptake rate2015Inngår i: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 80, 45-52 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Temperature profoundly affects saprotrophic respiration rates, and carbon quality theory predicts that the rates' temperature Sensitivity should increase as the quality of the carbon source declines. However, reported relationships between saprotrophic respiration responses to temperature and carbon quality vary widely. Some of this variability may arise from confounding effects related to both substrate quality and substrate availability. The importance of these variables, as well as substrate diffusion and uptake rates, for the temperature sensitivity of saprotrophic respiration has been validated theoretically, but not empirically demonstrated. Thus, we tested effects of varying substrate uptake rates on the temperature sensitivity of organic carbon degradation. For this purpose we created a model system using the organic layer (O-horizon), of a boreal forest soil, specifically to test effects of varying monomer uptake and release rates. The addition of both monomers and polymers generally increased the temperature sensitivity of saprotrophic respiration. In response to added monomers, there was a linear increase in the temperature sensitivity of both substrate-induced respiration and the specific growth rate with increasing rate of substrate uptake as indicated by the CO2 production at 14 degrees C. Both of these responses diverge from those predicted by the carbon quality theory, but they provide the first empirical evidence consistent with model predictions demonstrating increased temperature sensitivity with increased uptake rate of carbon monomers over the cell membrane. These results may explain why organic material of higher carbon quality induces higher temperature responses than lower carbon quality compounds, without contradicting carbon quality theory. 

  • 31. Eriksson, Ann Kristin
    et al.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. Swedish University of Agricultural Sciences, Sweden.
    Hesterberg, Dean
    Phosphorus speciation of clay fractions from long-term fertility experiments in Sweden2015Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 241, 68-74 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Phosphorus (P) losses from agricultural soils constitute a main driver for eutrophication of the Baltic Sea. There is limited knowledge about sorption and release processes of P in these soils, especially concerning the effects of fertilization. In this study, P speciation of the clay fractions from six different soils in long-term fertility experiments in Sweden was investigated by P K-edge XANES spectroscopy. As expected, unfertilized soils had lower concentrations of acid-digestible P compared with fertilized soils. Based on best-fit standards that emerged from linear combination fitting (LCF) of XANES spectra, phosphate sorbed on iron (Fe) (hydr)oxides was a dominant P species in clay fractions from unfertilized soils containing more than 35 mmol kg(-1) of oxalate-extractable Fe. In contrast, P sorbed on aluminum (Al) (hydr)oxides predominated in soils with lower concentrations of oxalate-extractable Fe. A greater proportion of organically bound P was fit for soil samples containing >2% organic carbon. The soils included one calcareous soil for which a greater proportion of P was fit as apatite. After long-term fertilization, P had accumulated mainly as P adsorbed to Al (hydr) oxides according to the XANES analysis. Our research shows that P speciation in fertilized agricultural soils depended on the level of P buildup and on the soil properties.

  • 32. Eriksson, Ann Kristin
    et al.
    Hillier, Stephen
    Hesterberg, Dean
    Klysubun, Wantana
    Ulén, Barbro
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. Swedish University of Agricultural Sciences, Sweden.
    Evolution of phosphorus speciation with depth in an agricultural soil profile2016Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 280, 29-37 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With time, different soil-forming processes such as weathering, plant growth, accumulation of organic matter, and cultivation are likely to affect phosphorus (P) speciation. In this study, the depth distribution of P species was investigated for an agricultural clay soil, Lanna, Sweden. Small amounts of apatite-P was demonstrated in the topsoil whereas the speciation of Pat 70-100 cm depth consisted of approximately 86% apatite according to P K-edge XANES (X-ray absorption near-edge structure) spectroscopy. Because there were only minor differences in bulk mineralogy and texture, these variations in P speciation were interpreted as the result of apatite weathering of the topsoil. Speciation modeling on soil extracts supported this idea: hydroxyapatite was not thermodynamically stable in the top 50 cm of the soil. Apatite was enriched in the bulk soil relative to the clay fraction, as expected during apatite dissolution. Combined results from batch experiments, XANES spectroscopy and X-ray diffraction suggested chemical transformations of the topsoil as a result from accumulation of organic matter and airing from tillage followed by enhanced weathering of apatite, amphiboles, clay minerals, and iron oxides. This caused the formation of poorly crystalline secondary iron and aluminum (hydr)oxides in the topsoil, which retained part of the released P from apatite. Other P was incorporated into organic forms. Furthermore, the results also showed that short-term acidification below the current pH value (below 5.5 in the topsoil and 7.2 in the deeper subsoil) caused significant solubilization of P. This is attributed to two different mechanisms: the instability of Al-containing sorbents (e.g. Al hydroxides) at low pH (in the topsoil), and the acid-mediated dissolution of apatite (the subsoil).

    Fulltekst tilgjengelig fra 2018-06-16 09:35
  • 33.
    Eveborn, David
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Miljögeokemi och ekoteknik.
    Bed filters for phosphorus removal in on-site wastewater treatment: Removal mechanisms and sustainability2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    For many surface waters, phosphorus (P) leaching is a serious problem that should be minimized to prevent eutrophication. In Sweden there is a demand for physical and technical development of high-performance P removal techniques to reduce phosphorus leaching from on-site wastewater treatment systems to the Baltic Sea. However, although these systems are designed to reduce eutrophication there are also other environmental impacts to be considered when implementing them in on-site systems; energy use and global warming potential are two examples. This study has investigated several bed filter materials (reactive media and natural soils) for their total environmental impact (in commercial applications) as well as for the predominating chemical phosphorus removal mechanisms. The use of life cycle assessment revealed that several reactive bed filters are relatively energy-consuming due to the material manufacturing process. Characterization of phosphorus compounds in used reactive media provided evidence for calcium phosphate precipitation as the predominating P removal mechanism in alkaline filter materials. However, in soil treatment systems with noncalcareous soils, batch experiments and extractions suggested that aluminium compounds were important for P removal. According to mass balance calculations that compared accumulated P with the estimated P load in a soil treatment system, the long term P removal capacity was very low; only 6.4 % of the applied phosphorus had been removed during 16 years of operation.

  • 34.
    Eveborn, David
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630), Miljögeokemi och ekoteknik.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630), Miljögeokemi och ekoteknik.
    Hesterberg, Dean
    University Raleigh, Department of Soil Science, North Carolina, USA.
    Hillier, Stephen
    Macaulay Institute, Craigiebuckler, Aberdeen, UK.
    XANES Speciation of P in Environmental Samples: An Assessment of Filter Media for on-Site Wastewater Treatment2009Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, nr 17, 6515-6521 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    X-ray absorption near edge structure (XANES) spectroscopyis a useful technique for characterization of chemical speciesof phosphorus in complex environmental samples. To developand evaluate bed filters as sustainable on-site wastewater treatment solutions, our objective in this study was to determine the chemical forms of accumulated phosphorus in a selectionof promising filter materials: Filtralite P, Filtra P, Polonite, Absol, blast furnace slag, and wollastonite. Full-scale operational wastewater-treatment systems were sampled and in addition, filter samples collected from laboratory studies provided access to additional media and complementary samples.Phosphorus species were characterized using phosphorus K-edge XANES spectroscopy, complemented by X-ray powder diffraction (XRPD) and attenuated total reflectance Fouriertransform infrared spectroscopy (ATR-FTIR). No systematic differences could be seen in the results between laboratory and full-scale samples. All six filter media contained significant amounts of crystalline calcium phosphates. Some samples also contained amorphous calcium phosphate (>60 % of totalP in Absol). In Filtralite P and blast furnace slag, more than 35 % of the accumulated phosphorus was associated with Fe or Al. Both the power and shortcomings of XANES analysis for characterizing P species in these filter media are discussed.

  • 35.
    Eveborn, David
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Miljögeokemi och ekoteknik.
    Kong, Deguo
    Department of Applied Environmental Science, Stockholm University, Sweden.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Miljögeokemi och ekoteknik.
    Wastewater treatment by soil infiltration: Long-term phosphorus removal2012Inngår i: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009, Vol. 140, 24-33 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Phosphorus (P) leaching from on-site wastewater treatment systems may contribute to eutrophication. In developed countries the most common on-site treatment technique is septic systems with soil infiltration. However, the current knowledge about long term P removal in soil treatment systems is not well developed and the data used for estimation of P losses from such systems are unreliable. In this study we sampled four filter beds from community-scale soil treatment systems with an age of between 14 and 22 years to determine the long-term P removal and to investigate the chemical mechanisms behind the observed removal. For one site the long-term P removal was calculated using a mass balance approach. After analysis of the accumulated P. it was estimated that on average 12% of the long-term P load had been removed by the bed material. This indicates a low overall capacity of soil treatment systems to remove phosphorus. Batch experiments and chemical speciation modelling indicated that calcium phosphate precipitation was not an important long-term P removal mechanism, with the possible exception of one of the sites. More likely, the P removal was induced by AlPO4 precipitation and/or sorption to poorly ordered aluminium compounds, as evidenced by strong relationships between oxalate-extractable Al and P.

  • 36.
    Faisal, Ayad A. H.
    et al.
    Department of Environmental Engineering, College of EngineeringUniversity of Baghdad.
    Kubba, Faris A.
    Department of Environmental Engineering, College of EngineeringUniversity of Al-Mustansiriyah.
    Madhloom, Huda M.
    Department of Civil Engineering, College of EngineeringUniversity of Al-Mustansiriyah.
    Modeling of Trichloroethylene Migration in Three-Dimensional Saturated Sandy Soil2014Inngår i: Arabian Journal for Science and Engineering, ISSN 2193-567X, Vol. 39, nr 11, 7763-7769 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study characterized the temporal and spatial distribution of trichloroethylene (TCE) dissolved plume from continuous source in 3D bench-scale sand aquifer. COMSOL Multiphysics 3.5a (2008) software based on the finite element numerical scheme taking into account the sorption process was used to interpreted the experimental results. A conservative tracer is employed for the determination of the longitudinal dispersivity. The sorption characteristics of TCE onto the aquifer sand are independently determined from batch equilibrium data. TCE concentrations at specific downstream locations within the aquifer for different periods of time are measured under flow rates values equal to 20, 40 and 100 ml/min. The predicted TCE concentrations were found to be reasonably agreed with the bench-scale experimental results with mean error <5%.

  • 37. Ferro-Vazquez, C.
    et al.
    Novoa-Munoz, J. C.
    Costa-Casais, M.
    Klaminder, Jonatan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Martinez-Cortizas, A.
    Metal and organic matter immobilization in temperate podzols: a high resolution study2014Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 217, 225-234 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aluminium and Fe fractions were obtained in samples from two temperate podzols by selective extraction with NaOH (Al-n, Fe-n), Na-dithionite-citrate (Al-d, Fe-d), acid NH4-oxalate (Al-o, Fe-o) and Na-pyrophosphate (Al-p, Fe-p) following the traditional fractionation procedures, and also by the use of the chlorides of K (Al-K), La (Al-La) and Cu (Al-cu) as non-buffered extractants for Al. Carbon content was also determined in the Na-pyrophosphate extract (C-p). Soil sampling was done at high-resolution to allow a more detailed characterization of the vertical processes than the traditional sampling by whole soil horizons. Results showed that Al-p and Fe-p make a large proportion of the Alo and Fe-o meaning that organoaluminic complexes dominated in the "active" metal pool instead of inorganic compounds. The degree of metal saturation of soil organic matter (estimated by the (Al-p Fe-p)/C-p molar ratios) increases with depth, especially in the uppermost samples of spodic horizons (Bhs1) where it increases up to 0.1. Aluminium dominates in the adsorption positions of the organic matter in the spodic horizon (Fe-p/Al-p ratios <0.5), except in the Bhs1 horizon (ratios > 1), indicating that the immobilization of Fe containing complexes occurs 10-15 cm above that of Al The highly stable Al-OM complexes accounted on average for 60% of the organoaluminic associations (>70% in the Bhs horizons). The moderately stable complexes predominate in A horizons (57-77% in ACB1 and 37-48% in ACB2) and the largest proportions of low stability complexes were found in the uppermost samples of the spodic horizons (Bhs1) of both soils (9-21%), together with the highest Fep contents and a decrease in pH values. From a stepwise multiple regression model it is suggested that pH is the main variable accounting for the stability of Al-OM compounds together with C and organically bound Fe contents. It is suggested that the illuviation of unsaturated organic acids lower the pH in upper spodic horizons, leading to the complexation of metals from formerly precipitated organometallic complexes and/or leading to their redissolution, enabling their migration to deeper soil layers. Iron complexes would be less soluble at soil pH, resulting in a differentiation of an upper Fe-rich Bhs1 horizon and a lower Bhs2 Al-rich horizon. The depth variation in C accumulation was found to be related to the proportion of highly stable Al-OM fraction.

  • 38.
    Figueiredo, V.
    et al.
    University of Federal Fluminense, Brazil; University of Federal Rio de Janeiro, Brazil.
    Enrich Prast, Alex
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. University of Federal Rio de Janeiro, Brazil.
    Ruetting, T.
    University of Gothenburg, Sweden.
    Soil organic matter content controls gross nitrogen dynamics and N2O production in riparian and upland boreal soil2016Inngår i: European Journal of Soil Science, ISSN 1351-0754, E-ISSN 1365-2389, Vol. 67, nr 6, 782-791 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the pathways of gross soil nitrogen (N) transformations and nitrous oxide (N2O) production with N-15 enrichment techniques in a boreal forest landscape by comparing organic (riparian) and mineral (upland) soil within two catchments in northern Sweden. The values of all soil properties evaluated for the riparin and upland zones were statistically different (Pamp;lt;0.05). The rates of gross N transformation were larger in the riparian than in the upland soil (Pamp;lt;0.05), which can be explained by the larger soil organic matter (SOM) content that provides energy and mineral N as a substrate for other processes. The riparian soil at one site shows a decoupling of nitrification from mineralization; the largest gross mineralization occurred in the soil at this site, but gross nitrification was relatively small. This was probably because of the low pH (2.70.1), which inhibits the activity of autotrophic nitrifiers. Oxidation of organic N was the main source of N2O in the soil at all sites, probably because of low soil pH and large organic carbon content, which favours heterotrophic nitrification. The results of our study confirm that organic matter is the main regulating factor for gross N mineralization and nitrification; the latter are markedly different in the organic-rich riparian soil and the upland soil in the boreal forest landscape.

  • 39. Fröberg, M.
    et al.
    Grip, H.
    Tipping, E.
    Svensson, Magnus
    Swedish University of Agricultural Sciences, Department of Soil and Environment, P.O. Box 7014, SE-75007 Uppsala, Sweden.
    Strömgren, M.
    Kleja, D. B.
    Long-term effects of experimental fertilization and soil warming on dissolved organic matter leaching from a spruce forest in Northern Sweden2013Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 200-201, 172-179 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nitrogen deposition and increasing temperature are two of the major large-scale changes projected for coming decades and the effect of this change on dissolved organic matter is largely unknown. We have utilized a long-term fertilization and soil warming experiment in Northern Sweden to study the effects of increased nutrient levels and increased temperature on DOC transport under the O horizon. The site is N limited and mean annual temperature 2. °C. Experimental fertilization with ammonium nitrate and a physiological mixture of other macro- and micro-nutrients has been going on for 22. years and soil warming, 5. °C above ambient soil temperature for 14. years, prior to the study. Experimental plots have been irrigated to avoid drying and we also studied the effect of this long-term irrigation on DOC by establishing control plots receiving no irrigation.DOC concentrations and fluxes under the O horizon were approximately 50% higher in fertilized plots than in non-fertilized control plots. We did not find any statistically significant effect of soil warming. There was a statistically significant effect of long-term irrigation on DOC with higher DOC concentration and fluxes in irrigated plots than in plots without irrigation. There were no major effects on DOC quality measured by specific UV absorbance. Fertilization approximately doubled soil organic matter stocks in the O horizon, whereas there were no such effects of warming or irrigation on soil organic matter amounts. There was no statistically significant treatment effect on DOC collected from the B horizon. We hypothesize that the positive effect of fertilization on DOC is related to increased soil C stocks.

  • 40.
    Gardfors, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Föroreningsspridning via ledningsgravar: en fältstudie på Köpmanholmens industriområde2005Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sewer trenches usually contain material with a higher hydraulic conductivity then the adjacent soil. Thus they can serve as paths of preferential flow in a polluted area. Wastewater from factories can also leak from wastewater pipes and pollute the soil in the sewer trenches.

    The purpose of this project was to investigate pollutions in sewer trenches and in sewer pipes in the industrial area of Köpmanholmen, 20 km south of Örnsköldsvik in the north of Sweden. To make an estimation concerning the potential of transport of pollutions in sewer trenches, hydrological calculations were performed.

    Leakage to any greater extent did not seem to be a problem in the area. This is the case both for the concrete and the wooden pipes that have served as factory wastewater pipes. A large transport in the lengthwise direction of the sewer trenches was not shown to exist. Instead the greatest risk of transport from a polluted area seems to come from infiltration into wastewater pipes, where the pollutants can flow readily to the recipient or wastewater treatment plant.

  • 41. Gebrehiwot, S. G.
    et al.
    Ilstedt, U.
    Gardenas, A. I.
    Bishop, Kevin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Hydrological characterization of watersheds in the Blue Nile Basin, Ethiopia2011Inngår i: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 15, nr 1, 11-20 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thirty-two watersheds (31-4350 km(2)), in the Blue Nile Basin, Ethiopia, were hydrologically characterized with data from a study of water and land resources by the US Department of Interior, Bureau of Reclamation (USBR) published in 1964. The USBR document contains data on flow, topography, geology, soil type, and land use for the period 1959 to 1963. The aim of the study was to identify watershed variables best explaining the variation in the hydrological regime, with a special focus on low flows. Moreover, this study aimed to identify variables that may be susceptible to management policies for developing and securing water resources in dry periods. Principal Component Analysis (PCA) and Partial Least Square (PLS) were used to analyze the relationship between five hydrologic response variables (total flow, high flow, low flow, runoff coefficient, low flow index) and 30 potential explanatory watershed variables. The explanatory watershed variables were classified into three groups: land use, climate and topography as well as geology and soil type. Each of the three groups had almost equal influence on the variation in hydrologic variables (R-2 values ranging from 0.3 to 0.4). Specific variables from within each of the three groups of explanatory variables were better in explaining the variation. Low flow and low flow index were positively correlated to land use types woodland, dense wet forest and savannah grassland, whereas grazing land and bush land were negatively correlated. We concluded that extra care for preserving low flow should be taken on tuffs/basalts which comprise 52% of the Blue Nile Basin. Land use management plans should recognize that woodland, dense wet forest and savannah grassland can promote higher low flows, while grazing land diminishes low flows.

  • 42. Gharasoo, Mehdi
    et al.
    Centler, Florian
    Fetzer, Ingo
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. UFZ Helmholtz Center for Environmental Research, Germany.
    Thullner, Martin
    How the chemotactic characteristics of bacteria can determine their population patterns2014Inngår i: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 69, 346-358 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

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

  • 43.
    Giesler, Reiner
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Karina, E. Clemmensen
    Wardle, David A.
    Klaminder, Jonatan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Bindler, Richard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Boreal Forests Sequester Large Amounts of Mercury over Millennial Time Scales in the Absence of Wildfire2017Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 5, 2621-2627 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alterations in fire activity due to climate change and fire suppression may have profound effects on the balance between storage and release of carbon (C) and associated volatile elements. Stored soil mercury (Hg) is known to volatilize due to wildfires and this could substantially affect the land air exchange of Hg; conversely the absence of fires and human disturbance may increase the time period over which Hg is sequestered. Here we show for a wildfire chronosequence spanning over more than 5000 years in boreal forest in northern Sweden that belowground inventories of total Hg are strongly related to soil humus C accumulation (R-2 = 0.94, p < 0.001). Our data clearly show that northern boreal forest soils have a strong sink capacity for Hg, and indicate that the sequestered Hg is bound in soil organic matter pools accumulating over millennia. Our results also suggest that more than half of the Hg stock in the sites with the longest time since fire originates from deposition predating the onset of large-scale anthropogenic emissions. This study emphasizes the importance of boreal forest humus soils for Hg storage and reveals that this pool is likely to persist over millennial time scales in the prolonged absence of fire.

  • 44.
    Gustafsson, Eric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper. Institutionen för mark och miljö (SLU).
    Dimensionering av markavvattningssystem för jordbruksmark i nuvarande och framtida klimat: En pilotstudie på olika typjordar2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I Sverige finns idag inom jordbruket runt 30 000 markavvattningsföretag och det räknas med att 1,3 miljoner hektar av jordbruksmarken är dikad. Tidigare undersökningar har visat att flera av dessa dräneringssystem som byggdes för 60–100 år sedan inte längre är anpassade för det nuvarande klimatet och att dagens riktvärde på 1,2 m djup för dräneringsledningarna bör ses över. Detta, i samband med att klimatförändringarna väntas leda till bland annat en ökad årlig nederbörd, ställer Sverige inför stora utmaningar att anpassa dräneringssystemen därefter. En väldränerad jordbruksmark är en förutsättning för att minimera kväveläckage och säkra den nuvarande samt i framtiden ökade matproduktionen som krävs för att underhålla en växande befolkning.

    Syftet har varit att med hjälp av hydrologimodellen DRAINMOD dimensionera dräneringssystem för två fält med olika markfysikaliska egenskaper som är anpassade för dagens samt framtidens klimat.

    DRAINMOD simulerar grundvattennivån mellan två dräneringsrör och kan med hjälp av grödparametrar såsom rotdjup och längd på odlingssäsonger uppskatta den relativa avkastningen för en specifik gröda med hjälp av ett stressindex. Detta stressindex beräknas av DRAINMOD baserat på över- eller underskott av vatten i markprofilen. DRAINMOD beräknar även vattenförluster i form av dränering, ytavrinning samt evapotranspiration. Efter att modellen validerats mot historiska klimatdata testades varje fält mot genererad framtida klimatdata. Flera olika dräneringsdjup och avstånd analyserades med avseende på dränering, ytavrinning och relativ avkastning. Det ena fältet beläget i Östergötland, med ett dräneringsdjup på riktvärdet 1,2 m och ett dräneringsavstånd på 25–50 m ger en minimerad dränerad volym samt en relativ avkastning på 80–100 % i ett framtida klimat. Det andra fältet beläget i Skåne uppnådde en minimerad dränerad volym och en relativ avkastning på 100 % vid dräneringsdjup på 0,9 m och ett avstånd mellan ledningarna på 20–50 m.

  • 45.
    Gustafsson, Jon Petter
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    Mwamila, Luhuvilo B.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    Kergoat, Kevin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    The pH dependence of phosphate sorption and desorption in Swedish agricultural soils2012Inngår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 189, 304-311 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A number of previous studies have reported the existence of a minimum in phosphate solubility between pH 5.5 and 7 in non-calcareous soils. Different hypotheses have been forwarded to explain this phenomenon. In this study, ten soil samples with varying textures and phosphorus status were subjected to batch experiments in which dissolved phosphate was measured as a function of pH and phosphate load. Soil samples with more than 20% clay all had a minimum phosphate solubility between pH 6 and 7, whereas for samples with <10% clay, no such minimum was observed. Further experiments involving additions of phosphate and arsenate showed an increasing adsorption of these anions with decreasing pH also below pH 6 in clay soils, suggesting that the pH dependence on adsorption and desorption in short-term experiments was not the same. Kinetic experiments showed that the increased phosphate desorption at lower pH values in non-calcareous clay soils was a quick process, which is consistent with adsorption/desorption being the most important mechanism governing the retention and release of inorganic P. Moreover, by comparing extraction results with batch experiment results for samples from a long-term fertility experiment, it was concluded that more than 60% of the accumulated phosphate was occluded, i.e. not reactive within 6 days. Additional evidence for an important role of occluded phosphate comes from an analysis of the Freundlich sorption isotherms for the studied soils. It is hypothesized that interlayered hydroxy-Al and hydroxy-Fe polymers in clay minerals may be important for P dynamics in clay soils by trapping some of the P in an occluded form. The results also suggest that improved knowledge on the speciation and dynamics of phosphorus in soils is required for consistent mechanistically based modeling of phosphate sorption/desorption reactions.

  • 46.
    Gustafsson, Jon Petter
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Tiberg, Charlotta
    Molybdenum binding to soil constituents in acid soils: An XAS and modelling study2015Inngår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 417, 279-288 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite its importance as a trace element, the binding mechanisms of molybdenum in soils are not well known. In this study, we studied the binding of molybdenum onto selected soil samples, and we used X-ray absorption spectroscopy (XAS) to characterize the coordination of molybdenum on three important environmental sorbents: ferrihydrite (Fh), amorphous aluminium hydroxide (Al(OH)(3)) and fulvic acid. The X-ray near-edge structure (XANES) data showed that the added molybdenum(VI) was not reduced, although for the organic samples the coordination shifted from tetrahedral to octahedral. The EXAFS (extended X-ray absorption fine structure) analysis showed that molybdenum(VI) on Fh and Al(OH)(3) was dominated by edge-sharing bidentate complexes with Mo center dot center dot center dot Fe and Mo center dot center dot center dot Al distances of 2.80 and 2.62 angstrom, respectively. For ferrihydrite, there was a minor contribution from a corner-sharing bidentate complex at 3.55 angstrom. Further, geochemical modelling suggested an additional role of an outer-sphere complex at high pH. A sample from a spodic Bs horizon had XANES and EXAFS features similar to those of Mo sorbed to Al(OH)(3), highlighting the importance of Al(OH)(3)-type sorbents in this soil. However, in the studied organic samples molybdenum(VI) was present in a distorted octahedral configuration as an organic complex. The results were used to improve molybdenum binding reaction equilibrium constants in the CD-MUSIC model for ferrihydrite and in the Stockholm Humic Model. Collectively the results show that acid soils may contain sorbents able to bind molybdenum efficiently, and thus prevent its leaching to waters.

  • 47.
    Hansson, Pernilla
    et al.
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper.
    Sanfridsson, Christina
    Karlstads universitet, Fakulteten för samhälls- och livsvetenskaper.
    Analys av artificiella marktyper vid vatten med hjälp av GIS, Värmlands län 20072007Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    On commission of the County administrative board in Värmland County a method was developed for analysis of the occurrence of artificial land use at lakes and watercourses. With artificial land use is meant land significantly affected by man. Two bases have been used to carry out the analysis. In one of the analysis the vegetation database and in the other GSD¹-Marktäckedata (land cover data) was used (this method has been used by County administrative board in Jönköping County).

    The analysis comprises all watercourses within Alsterälven river basin. The digital water bodies are created by the Swedish Meteorological and Hydrological Institute on the basis of GSD-Översiktskartan (general map). The water layer is derived from GSD-Fastighetskartan (property map) and has been used as water theme in both analyses. In order to make them match each other two models have been used, one manual and one automatic.

    Vegetation data and GSD-Marktäckedata have been complemented with information about cut forest from the Swedish Forest Agency and roads from the Swedish Road Administration. Vegetation data has also been completed with power line area from the forest phase layer and GSD-Marktäckedata with buildings from GSD-Fastighetskartan. The definition artificial land uses has been classified in the vegetation data according to environmental quality criteria; cut forest, field and building sites. In the GSD-Marktäckedata has artificial land use has been classified to environmental quality criteria; cut forest, field, buildings and building sites. The artificial land use types have been summarized individually, totally and indicated as percentage of the total area. The results of the assessment are expressed in a scale of 1-5 for each water body.

    The resolution of the vegetation database is lower than in the GSD-Marktäckedata. The comparison between the vegetation database and GSD-Marktäckedata shows that artificial land use differ in area. In the vegetation database buildings are included in the data base, in GSD-Marktäckedata buildings with a buffer at 20 meters were added to the base map. The buildings in GSD-Marktäckedata cover “more space” and the percentage artificial land became larger.

  • 48. He, H.
    et al.
    Jansson, Per-Erik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Svensson, Magnus
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Meyer, A.
    Klemedtsson, L.
    Kasimir, Å.
    Factors controlling Nitrous Oxide emission from a spruce forest ecosystem on drained organic soil, derived using the CoupModel2016Inngår i: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 321, 46-63 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High Nitrous Oxide (N2O) emissions have been identified in hemiboreal forests in association with draining organic soils. However, the specific controlling factors that regulate the emissions remain unclear. To examine the importance of different factors affecting N2O emissions in a spruce forest on drained organic soil, a process-based model, CoupModel, was calibrated using the generalized likelihood uncertainty estimation (GLUE) method. The calibration also aims to estimate parameter density distributions, the covariance matrix of estimated parameters and the correlation between parameters and variables information, useful when applying the model on other peat soil sites and for further model improvements. The calibrated model reproduced most of the high resolution data (total net radiation, soil temperature, groundwater level, net ecosystem exchange, etc.) very well, as well as cumulative measured N2O emissions (simulated 8.7±1.1kgN2Oha-1year-1 (n=97); measured 8.7±2.7kgN2Oha-1year-1 (n=6)), but did not capture every measured peak. Parameter uncertainties were reduced after calibration, in which 16 out of 20 parameters changed from uniform distributions into normal distributions or log normal distributions. Four parameters describing bypass water flow, oxygen diffusion and soil freezing changed significantly after calibration. Inter-connections and correlations between many calibrated parameters and variables reflect the complex and interrelated nature of pedosphere, biosphere and atmosphere interactions. This also highlights the need to calibrate a number of parameters simultaneously. Model sensitivity analysis indicated that N2O emissions during growing seasons are controlled by competition between plants and microbes for nitrogen, while during the winter season snow melt periods are important. Our results also indicate that N2O is mainly produced in the capillary fringe close to the groundwater table by denitrification in the anaerobic zone. We conclude that, in afforested drained peatlands, the plants and groundwater level have important influences on soil N availability, ultimately controlling N2O emissions.

  • 49.
    Hjulström, Björn
    et al.
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur. Arkeologiska Forskningslaboratoriet.
    Isaksson, Sven
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur. Arkeologiska Forskningslaboratoriet.
    Dolda spår av forntida verksamhet2007Inngår i: Hus och bebyggelse i Uppland: Delar av förhistoriska sammanhang, 2007Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 50.
    Hylander, Lars D.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Günther, Folke
    Lund University.
    34 Sustainable Agriculture and Climate: Saving Soils with Biochar2012Inngår i: Sustainable Agriculture / [ed] Christine Jakobsson, Uppsala: Baltic University Press , 2012, 1500, 247-249 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
123 1 - 50 of 115
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