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  • 1.
    Alakangas, Linda J.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. SKB, Äspo Hard Rock Lab, Oskarshamn.
    Mathurin, Frédéric A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Faarinen, Mikko
    ALS Scandinavia AB Luleå.
    Wallin, Bill
    Geokema AB, Lidingö.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sampling and Characterizing Rare Earth Elements in Groundwater in Deep-Lying Fractures in Granitoids Under In Situ High-Pressure and Low-Redox Conditions2014In: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 20, no 4, p. 405-418Article in journal (Refereed)
    Abstract [en]

    Several countries are preparing to dispose of radioactive nuclear waste deep underground in crystalline rock. This type of bedrock is commonly extensively fractured and consequently carries groundwater that serves as a medium for transporting metals and radionuclides. A group of metals of particular interest in this context is the rare earth elements (REEs), because they are analogues of actinides contained within radioactive waste and are tracers of hydrological pathways and geochemical processes. Concentrations of REEs are commonly low in these groundwaters, leading to values below detection limits of standard monitoring methods, particularly for the heavy REEs. We present a new technical set-up for monitoring REEs (and other trace metals) in groundwater in fractured crystalline rock. The technique consists of passing the fracture groundwater, commonly under high pressure and containing reduced chemical species, through a device that maintains the physicochemical character of the groundwater. Within the device, diffusive gradient in thin-film (DGT) discs are installed in triplicate. With this set-up, we studied REEs in groundwater in fractures at depths of approximately -144, -280, and -450 m in granitoids in the A"spo Hard Rock Laboratory in southern Sweden. The entire REE suite was detected (concentrations down to 0.1 ng L-1) and was differently fractionated among the groundwaters. The shallowest groundwater, composed of dilute modern Baltic Sea water, was enriched in the heavy REEs, whereas the deeper groundwaters, dominated by old saline water, were depleted in the heavy REEs. Deployment periods varying from 1 to 4 weeks delivered similar REE concentrations, indicating stability and reproducibility of the experimental set-up. The study finds that 1 week of deployment may be enough. However, if the overall setting and construction allow for longer deployment times, 2-3 weeks will be optimal in terms of reaching reliable REE concentrations well above the detection limit while maintaining the performance of the DGT samplers.

  • 2.
    Augustsson, Anna
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Bergbäck, Bo
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats E.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Trace metals in recharge and discharge ground waters at two sites at the Baltic coast of Sweden2009In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 24, no 9, p. 1640-1652Article in journal (Refereed)
    Abstract [en]

    The distribution and controls of trace elements (Cd, Cr, Cu, Ni, Pb, Zn and U) in shallow groundwater in discharge and recharge zones were analysed at two sites on the Baltic coast of Sweden; one granite-dominated and one with a significant addition of calcite. Although the study sites differ in overburden geochemistry and groundwater trace metal concentrations, which were well reflected in the general groundwater composition, the relative hydrochemical differences between recharge and discharge ground waters were similar at both sites, and temporally stable. The concentrations of Cd, Cu, Ni and U were higher in soil tubes in recharge areas, but Cr was higher in discharge zones. Also concentrations of HS, Fe, Mn and NH4 were higher in discharge samples, which in combination with increased 34S values provide strong evidence of a transition from oxidizing to more reducing conditions along the groundwater flow gradient. In terms of trace metals, this might mean either mobilisation due to dissolution of trace-metal carrying Fe(III) and Mn(IV) phases, or immobilisation caused by precipitation of discrete trace-metal sulfides or co-precipitation with Fe sulfides. The results from this study show that the latter is dominant in both the carbonate and granite environments for the metals Cd, Cu and Ni. Chromium concentrations were likely coupled to organic complexation and were higher in discharge groundwater, where DOC was also more abundant. As the concentration of several potentially toxic trace metals were found to differ between recharge and discharge areas, a climate driven change in hydrology might have a substantial impact on the distribution of these metals.

  • 3.
    Augustsson, Anna
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Uddh Söderberg, Terese
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Jarsjo, J.
    Stockholm University.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Olofsson, B.
    KTH Royal Institute of Technology.
    Balfors, B.
    KTH Royal Institute of Technology.
    Destouni, G.
    Stockholm University.
    The risk of overestimating the risk-metal leaching to groundwater near contaminated glass waste deposits and exposure via drinking water2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 566, p. 1420-1431Article in journal (Refereed)
    Abstract [en]

    This study investigates metal contamination patterns and exposure to Sb, As, Ba, Cd and Pb via intake of drinking water in a region in southeastern Sweden where the production of artistic glass has resulted in a large number of contaminated sites. Despite high total concentrations of metals in soil and groundwater at the glassworks sites properties, all drinking water samples from households with private wells, located at a 30-640 m distance from a glassworks site, were below drinking water criteria from the WHO for Sb, As, Ba and Cd. A few drinking water samples showed concentrations of Pb above the WHO guideline, but As was the only element found in concentrations that could result in human exposure near toxicological reference values. An efficient retention of metals in the natural soil close to the source areas, which results in a moderate impact on local drinking water, is implied. Firstly, by the lack of significant difference in metal concentrations when comparing households located upstream and downstream of the main waste deposits, and secondly, by the lack of correlation between the metal concentration in drinking water and distance to the nearest glassworks site. However, elevated Pb and Cd concentrations in drinking water around glassworks sites when compared to regional groundwater indicate that diffuse contamination of the soils found outside the glassworks properties, and not only the glass waste landfills, may have a significant impact on groundwater quality. We further demonstrate that different mobilization patterns apply to different metals. Regarding the need to use reliable data to assess drinking water contamination and human exposure, we finally show that the conservative modelling approaches that are frequently used in routine risk assessments may result in exposure estimates many times higher than those based on measured concentrations in the drinking water that is actually being used for consumption. (C) 2016 Elsevier B.V. All rights reserved.

  • 4.
    Augustsson, Anna
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bergbäck, Bo
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Elert, M.
    Kemakta Konsult.
    Höglund, L. O.
    Kemakta Konsult.
    Kleja, D. B.
    Swedish Geotechnical Institute ; Swedish University of Agricultural Sciences.
    High metal reactivity and environmental risks at a site contaminated by glass waste2016In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 154, p. 434-443Article in journal (Refereed)
    Abstract [en]

    This study addresses the reactivity and risks of metals (Ba, Cd, Co, Cr, Cu, Ni, Pb, Zn, As and Sb) at a Swedish site with large glass waste deposits. Old glassworks sites typically have high total metal concentrations, but as the metals are mainly bound within the glass waste and considered relatively inert, environmental investigations at these kinds of sites are limited. In this study, soil and landfill samples were subjected to a sequential chemical extraction procedure. Data from batch leaching tests and groundwater upstream and downstream of the waste deposits were also interpreted. The sequential extraction revealed that metals in <2 mm soil/waste samples were largely associated with geochemically active fractions, indicating that metals are released from pristine glass and subsequently largely retained in the surrounding soil and/or on secondary mineral coatings on fine glass particles. From the approximately 12,000 m(3) of coarse glass waste at the site, almost 4000 kg of Pb is estimated to have been lost through corrosion, which, however, corresponds to only a small portion of the total amount of Pb in the waste. Metal sorption within the waste deposits or in underlying soil layers is supported by fairly low metal concentrations in groundwater. However, elevated concentrations in downstream groundwater and in leachates of batch leaching tests were observed for several metals, indicating on-going leaching. Taken together, the high metal concentrations in geochemically active forms and the high amounts of as yet uncorroded metal-rich glass, indicate considerable risks to human health and the environment.

  • 5. Backlund, K
    et al.
    Boman, A
    Frojdo, S
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    An analytical procedure for determination of sulphur species and isotopes in boreal acid sulphate soils and sediments2005In: Agricultural and food science, Vol. 14 (1), p. 70-82Article in journal (Refereed)
  • 6.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Gustafsson, Jon Petter
    Kungliga Tekniska Högskolan, Skolan för arkitektur och samhällsbyggnad (ABE), Institutionen för hållbar utveckling, miljövetenskap och teknik (SEED).
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Aluminium speciation in boreal catchments enriched in fluoride2012Conference paper (Other academic)
  • 7.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mathurin, Frédéric A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fluoride abundance and controls in fresh groundwater in Quaternary deposits and bedrock fractures in an area with fluorine-rich granitoid rocks2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 569, p. 948-960Article in journal (Refereed)
    Abstract [en]

    This study focuses on fluoride (F-) concentrations in groundwater in an area in northern Europe (Laxemar, southeast Sweden) where high F- concentrations have previously been found in surface waters such as streams and quarries. Fluoride concentrations were determined over time in groundwater in the Quaternary deposits ("regolith groundwater"), and with different sampling techniques from just beneath the ground surface to nearly -700 min the bedrock (fracture) groundwater. A number of potential controls of dissolved F- were studied, including geological variables, mineralogy, mineral chemistry and hydrology. In the regolith groundwater the F- concentrations (0.3-4.2 mg/L) were relatively stable over time at each sampling site but varied widely among the sampling sites. In these groundwaters, the F- concentrations were uncorrelated with sample (filter) depth and the water table in meters above sea level (masl), with the thicknesses of the groundwater column and the regolith, and with the distribution of soil types at the sampling sites. Fluoride concentrations were, however, correlated with the anticipated spatial distribution of erosional material (till) derived from a F-rich circular granite intrusion. Abundant release of F-from such material is thus suggested, primarily via dissolution of fluorite and weathering of biotite. In the fresh fracture groundwater, the F- concentrations (1.2-7.4 mg/L) were generally higher than in the regolith groundwater, and were uncorrelated with depth and with location relative to the granite intrusion. Two mechanisms explaining the overall high F- levels in the fracture groundwater were addressed. First, weathering/dissolution of fluorite, bastnasite and apophyllite, which are secondary minerals formed in the fractures during past hydrothermal events, and biotite which is a primary mineral exposed on fracture walls. Second, long water-residence times, favoring water-rock interaction and build-up of high dissolved F- concentrations. The findings are relevant in contexts of extraction of groundwater for drinking-water purposes. (C) 2016 Elsevier B.V. All rights reserved.

  • 8.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mathurin, Frédéric A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fluoride in groundwater of regolith and bedrock (0-900 meters depth) in a granitoidic setting, SE Sweden2013In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 77, no 5, p. 691-691Article in journal (Other academic)
  • 9.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mathurin, Frédéric A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Geological, mineralogical and hydrological controls of fluoride in fresh groundwater in Quaternary deposits and bedrock fractures in a coastal area with Proterozoic granitoidsManuscript (preprint) (Other academic)
  • 10.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mathurin, Frédéric A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Gustafsson, Jon Petter
    Swedish University of Agricultural Sciences ; KTH Royal Inst Technol, Sweden.
    Peltola, Pasi
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    The impact of fluoride on Al abundance and speciation in boreal streams2015In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 409, p. 118-124Article in journal (Refereed)
    Abstract [en]

    The impact of fluoride on the abundance and speciation of aluminium (Al) was investigated in three boreal streams characterised by overall high concentrations of fluoride and dissolved organic matter. Stream-water sampling was carried out several times a year for at least 4 years, and a chemical equilibrium model (Visual MINTEQ) was applied in order to model the proportion of colloidal and organically/inorganically complexed Al in the waters. The Al concentrations in filtered (0.45 mu m) water samples were inversely correlated with pH, and reached values up to approximately 1 mg/L during low pH conditions (pH < 6.0). In a stream with high fluoride concentrations, as compared to a similar stream with only moderately elevated fluoride concentrations, the Al concentrations were consistently elevated. For the stream with high concentrations of fluoride and Al, the model predicted both high concentrations and proportions of Al-fluoride complexation. This prediction indicates that high fluoride levels contribute to raise both the Al abundance and the ratio of inorganic to organic Al complexation in stream water. In contrast, for another stream with high fluoride concentrations and consistently high (near neutral) pH, there was no evidence of fluoride affecting Al concentration or complexation. These results show that it is important to focus future studies on the role of high levels of dissolved fluoride on both the speciation and the toxicity of Al in stream water.

  • 11.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drake, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Fluoride patterns in a boreal stream influenced by bedrock and hydrology2011In: Goldschmidt Conference Abstracts 2011. Mineralogical Magazine, Vol. 75 (3), 2011, p. 517-517Conference paper (Refereed)
  • 12.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drake, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Impact of a Fluorine-Rich Granite Intrusion on Levels and Distribution of Fluoride in a Small Boreal Catchment2012In: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 18, no 2, p. 77-94Article in journal (Refereed)
    Abstract [en]

    This paper explores the influence of a fluorine-rich granite on fluoride concentration in a small boreal catchment in northern Europe. The materials include stream water and shallow groundwater sampled in spatial and temporal dimensions, and analytical data on fluoride and a number of ancillary variables. Fluoride increased strongly towards the lower reaches of the catchment—at the stream outlet the concentrations were up to 4.2 mg L −1 and 1.6–4.7 times higher than upstream. Additionally, fluoride concentrations were particularly high in groundwater and small surface-water bodies (including quarries) above or in direct contact with the granite and showed a strong inverse correlation with water discharge in the stream. Taken together, these data and patterns pin-point the granite intrusion as the ultimate source, explaining the abundance and distribution of dissolved fluoride within the catchment. The granite most likely deliver fluoride to the stream by three mechanisms: (1) weathering of the fine fraction of glacial deposits, derived from the granite and associated fluorine-rich greisen alterations, (2) large relative input of baseflow, partially originating in the granite and greisen, into the lower reaches during low flow in particular, and (3) water-conducting fractures or fracture zones running through the fluorine-rich granite and greisen.

  • 13.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Yu, Changxun
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Peltola, Pasi
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Daniel
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fluorine geochemistry of Quaternary deposits in a nemo-boreal catchment with elevated dissolved fluoride in surface waters and groundwaterManuscript (preprint) (Other academic)
  • 14.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Yu, Changxun
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Peltola, Pasi
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Daniel
    Aspö Hard Rock Lab, Oskarshamn.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Fluorine geochemistry of quaternary deposits in a nemo-boreal catchment with elevated dissolved fluoride in surface waters and groundwater2016In: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 170, p. 148-156Article in journal (Refereed)
    Abstract [en]

    This study focuses on fluorine (F) concentrations and solid-phase speciation in Quaternary deposits, including till, sorted sediments (gravel, sand, clay/silt) and organic-rich soil types, in an area in southeast Sweden underlain by 1.8 Ga granites and quartz monzodiorites with moderate F concentrations (0.11-0.13 wt%) and an outcrop (5 km in diameter) of 1.45 Ga granite (the Gotemar granite) with high to very high F concentrations (0.38-0.54 wt%). Eighteen <1 to 5 m thick profiles were sampled both upon and in the vicinity of the Gotemar granite. The F concentrations in the Quaternary deposits were considerably lower than in the underlying fresh bedrock, with the overall highest concentrations in glacial clay having values up to 660 ppm. A contributing factor to the low F concentrations in the till, as compared to the fresh rock, is release and leaching of fluoride (F-) during alteration of biotite and amphiboles to secondary minerals. Sequential chemical extractions showed that the F in the Quaternary deposits exists mainly in the residual fraction, and also to a substantial extent in phases extractable with hydroxylamine hydrochloride in the till and in phases extractable with Na pyrophosphate in the organic-rich soil types. These features indicate that after release via alteration of primary minerals, F- has to a significant extent been scavenged by Fe/Al (and perhaps Mn) oxyhydroxides in the till and by labile organic matter in the organic soil types. The high F- concentrations previously reported for stream waters and regolith groundwaters in the area are due to weathering and leaching of the Quaternary deposits and discharge of fluoride-rich waters from underlying bedrock fractures. (C) 2016 Elsevier B.V. All rights reserved.

  • 15.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drake, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    High fluoride concentrations in surface water: example from a catchment in SE Sweden2010In: Abstract Volume of COST Action 637- METEAU 4th International Conference. Kristianstad, Sweden, October 13-15, 2010. / [ed] Bhattacharya, P., Sandhi, A. and Rosborg, I., Stockholm: Department of Land and Water Resources Engineering, Royal Institute of Technology , 2010, p. 80-81Conference paper (Other academic)
  • 16. Boman, Anton
    et al.
    Fröjdö, Sören
    Backlund, Krister
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Impact of isostatic land uplift and artificial drainage on oxidation of brackish-water sediments rich in metastable iron sulfide2010In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, no 4, p. 1268-1281Article in journal (Refereed)
    Abstract [en]

    This study examines the dynamics of sulfur and trace elements (As, Co, Mo, Ni, Ti and Zn) when brackish-water sediments, unusually rich in metastable iron sulfide (probably a mixture of mackinawite and greigite), are brought into the oxidation zone by postglacial isostatic land uplift and farmland drainage. When subaqueous sediments approach the sea level, metastable iron sulfide is oxidized in the upmost layers and pyrite preserved and even accumulated concomitantly trapping Co, Ni and Zn but not As and Mo. When the land uplift has brought the sediments above sea level and natural drainage thus is initiated, the pyrite is oxidized and Co, Ni and Zn are released and transported down the profile. If this setting remained undisturbed, the slightly oxidized sediment (unripe soil) would become covered by peat and thus protected from further oxidation and metal translocation. Often these sediments are, however, artificially drained resulting in extensive oxidation and fast soil-profile development. The soil is an acid sulfate (AS) soil, characterized by low pH (<4), extensive leaching of metals and an abundance of disseminated brownish Fe(III) precipitates. We suggest that the fast soil development is due to initial oxidation of metastable iron sulfide, followed by pyrite oxidation. Drain bottom sediment, which in terms of chemistry and S-isotopes resembled that of the surfacing sea bottom strata, acted during the sampling period as a sink for metals. The abundant preservation of metastable iron sulfide below the groundwater table, even long periods after uplift above the sea level, is a puzzling feature. We suggest that it is the net result of sulfur starvation, an abundance of Fe(II) and strongly reducing conditions. (C) 2009 Elsevier Ltd. All rights reserved.

  • 17. Boman, Anton
    et al.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Fröjdö, Sören
    Sulfur dynamics in boreal acid sulphate soils rich in metastable iron sulfide – The role of artificial drainage2008In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 255, no 1-2, p. 68-77Article in journal (Refereed)
    Abstract [en]

    The sulfur dynamics of boreal brackish-water sediments rich in metastable iron sulfide (average elemental composition of FeS1.1), which upon oxidation have a huge impact on stream-water chemistry, were studied. Two cores, extending from the upper oxidized layer (acid sulfate soil) into the underlying iron sulfide-bearing sediment (potential acid sulfate soil) were collected at a site close to the sea level and at another site about 40 m above the latter in a region of current isostatic land uplift (Finland). The data clearly show, in contrast to what is often argued, that these notorious acidic soils are formed not as a result of the natural uplift but because of extensive ditching of farmlands. Above the depth of artificial drainage, S and Ni are abundantly lost, while beneath that level pyrite is abundant and metastable iron sulfide is increasing with depth, and the Ni concentration is relatively stable. In the narrow zone between the reduced and oxidized layers, the processes are dynamic and result in preservation of elemental S at one of the locations. The sulfur isotopic composition for metastable iron sulfide and pyrite in the investigated acid sulfate soils were found to be distinctly bimodal and roughly corresponding to a similar distribution in stream-water sulfate earlier reported from the same region. This indicates that pyrite is the main source of sulfate and acidity in some affected drains, while in others it is metastable iron sulfide.

  • 18.
    Brun, Christian
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Johansson, Maj-Britt
    Department of Soil and Environment, Swedish University of Agricultural Sciences.
    Spatial distribution of major, trace and ultra trace elements in three Norway spruce (Picea abies) stands in boreal forests, Forsmark, Sweden2010In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 159, no 3-4, p. 252-261Article in journal (Refereed)
    Abstract [en]

    The spatial distribution of 49 major, trace and ultra trace elements within a Norway spruce system was examined in three sites within the Forsmark area in central Sweden. The system included stemwood, roots, fresh green shoots, litterbags, humus, mineral soil, rhizosphere soil and moss. Based on Principal Component Analysis and manual plots the elements were grouped according to their distribution within the different compartments. One large group of elements occurring abundantly in the soil, and in much lower concentrations in the biota and litter was distinguished, containing mainly elements typically associated with soil minerals. A similar pattern was found for a second group of elements, but with higher concentrations in the biological samples and/or litter. In contrast, there was also one group of elements with high concentrations in biological samples and/or litter and low content in soil. This was mainly nutrients, but also the highly toxic Cd, Hg and Sb. This study is part of the site investigation programme, carried out by the Swedish Nuclear Fuel and Waste Management Company (SKB), in order to locate a suitable area for a deep repository for nuclear fuel waste.

  • 19.
    Brun, Christian
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Peltola, Pasi
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Johansson, Maj-Britt
    Biogeochemistry of Trace Elements in the Environment: Environmental Protection, Remediation and Human Health.2007In: Biogeochemistry of Trace Elements in the Environment: Environmental Protection, Remediation and Human Health., Proceedings of the 9th International Conference on the Biogeochemistry of Trace Elements in the Environment / [ed] Yongguan Zhu, Nicholas Lepp and Ravi Naidu, Beijing: Tsinghua University Press , 2007, p. 588-589Chapter in book (Other academic)
  • 20.
    Brun, Christian
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Peltola, Pasi
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Johansson, Maj-Britt
    Patterns in major and trace element dynamics during long-term decomposition of boreal forest litters2007In: GEOCHIMICA ET COSMOCHIMICA ACTA 71 (15), 2007Conference paper (Refereed)
  • 21.
    Brun, Christian
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Peltola, Pasi
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Johansson, Maj-Britt
    Trends in major and trace elements in decomposing needle litters during a long-term experiment in Swedish forests2008In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Plant and Soil, Vol. 306Article in journal (Refereed)
  • 22. Bärlund, I
    et al.
    Tattari, S
    Yli-Halla, M
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Measured and simulated effects of sophisticated drainage techniques on groundwater level and runoff hydrochemistry in areas of boreal acid sulphate soils2005In: Agricultural and food science, Vol. 14 (1), p. 98-111Article in journal (Refereed)
  • 23. Deng, H
    et al.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Björklund, A
    Geochemical and mineralogical properties of sulphide-bearing fine-grained sediments in Finland1998In: Environmental Geology, Vol. 36, p. 37-44Article in journal (Refereed)
  • 24.
    Destouni, Georgia
    et al.
    Stockholm University.
    Asokan, Shilpa
    Stockholm University.
    Augustsson, Anna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Balfors, Berit
    KTH Royal Institute of Technology.
    Bring, Arvid
    Stockholm University.
    Jaramillo, Fernando
    Stockholm University.
    Jarsjö, Jerker
    Stockholm University.
    Johansson, Emma
    Swedish Nuclear Fuel and Waste Management Co.
    Juston, John
    Stockholm University.
    Levi, Lea
    KTH Royal Institute of Technology.
    Olofsson, Bo
    KTH Royal Institute of Technology.
    Prieto, Carmen
    Stockholm University.
    Quin, Andrew
    Stockholm University.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Cvetkovic, Vladimir
    KTH Royal Institute of Technology.
    Biogeochemical Transformation Pathways through the Land-water Geosphere2014Conference paper (Refereed)
    Abstract [en]

    Water on land undergoes and participates in many biogeochemical exchanges and changes. A bits-and-pieces approach to these may miss essential aspects of change propagation and transformation by land-water through different segments of the Earth system. This paper proposes a conceptualization of the entire land-water geosphere as a scale-free catchment-wise organised system (Figure 1), emphasizing four key new system aspects compared to traditional hydrosphere/water cycle view: i) distinction of coastal divergent in addition to traditional convergent catchments; ii) physical and social-ecological system coupling through four main nodal zones/interfaces (surface, subsurface, coastal, observation); iii) flow-transport pathways as system coupling agents; iv) multiple interactions with the anthroposphere as integral system parts. Utilizing this conceptualization, we identify distinct patterns of direct anthropogenic change in large-scale water and waterborne nutrient fluxes, emerging across different parts of the world. In general, its embedment directly in the anthroposphere/technosphere makes land-water a key geosphere for understanding and monitoring human-driven biogeochemical changes. Further progress in system-level understanding of such changes requires studies of land-water as a continuous yet structured geosphere following the proposed spatiotemporal pathways of change propagation-transformation.

  • 25.
    Destouni, Georgia
    et al.
    Stockholm University, Sweden.
    Asokan, Shilpa M.
    Stockholm University, Sweden.
    Augustsson, Anna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Balfors, Berit
    The Royal Institute of Technology, Sweden.
    Bring, Arvid
    Stockholm University, Sweden.
    Jaramillo, Fernando
    Stockholm University, Sweden.
    Jarsjö, Jerker
    Stockholm University, Sweden.
    Johansson, Emma
    Stockholm University, Sweden ; Swedish Nuclear Fuel and Waste Management Co, Sweden.
    Juston, John
    Stockholm University, Sweden.
    Levi, Lea
    Stockholm University, Sweden ; The Royal Institute of Technology, Sweden ; University of Split, Croatia.
    Olofsson, Bo
    The Royal Institute of Technology, Sweden.
    Prieto, Carmen
    Stockholm University, Sweden.
    Quin, Andrew
    Stockholm University, Sweden.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Cvetkovic, Vladimir
    The Royal Institute of Technology, Sweden.
    Needs and means to advance science, policy and management understanding of the freshwater system: A synthesis report2015Report (Other academic)
    Abstract [en]

    Fragmented and inconsistent understanding of the freshwater system limits our ability to achieve water security and sustainability under the human-driven changes occurring in the Anthropocene. To advance system-level understanding of freshwater, gaps and inconsistencies in knowledge, data, representations and links of processes and subsystems need to be identified and bridged under consideration of the freshwater system as a continuous whole. 

    Based on such identification, a freshwater system conceptualization is developed in this report, which emphasizes four essential, yet often neglected system aspects:

    i) Distinction of coastal divergent catchments.

    ii) Four main zones (surface, subsurface, coastal, observation) of different types of freshwater change.

    iii) Water pathways as system-coupling agents that link and partition water change among the four change zones.

    iv) Direct interactions with the anthroposphere as integral system pathways across the change zones.

    We explain and exemplify some key implications of these aspects, identifying in the process also distinct patterns of human-driven changes in large-scale water fluxes and nutrient loads.

    The present conceptualization provides a basis for common inter- and trans-disciplinary understanding and systematic characterization of the freshwater system function and its changes, and of approaches to their modeling and monitoring. This can be viewed and used as a unifying checklist that can advance science, policy and management of freshwater and related environmental changes across various scales and world regions.

  • 26.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Heim, Christine
    Georg August Univ, Germany.
    Roberts, Nick M. W.
    British Geol Survey, UK.
    Zack, Thomas
    University of Gothenburg.
    Tillberg, Mikael
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. University of Gothenburg.
    Broman, Curt
    Stockholm University.
    Ivarsson, Magnus
    Swedish Museum Nat Hist.
    Whitehouse, Martin J.
    Swedish Museum Nat Hist.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Isotopic evidence for microbial production and consumption of methane in the upper continental crust throughout the Phanerozoic eon2017In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 470, p. 108-118Article in journal (Refereed)
    Abstract [en]

    Microorganisms produce and consume methane in terrestrial surface environments, sea sediments and, as indicated by recent discoveries, in fractured crystalline bedrock. These processes in the crystalline bedrock remain, however, unexplored both in terms of mechanisms and spatiotemporal distribution. Here we have studied these processes via a multi-method approach including microscale analysis of the stable isotope compositions of calcite and pyrite precipitated in bedrock fractures in the upper crust (down to 1.7 km) at three sites on the Baltic Shield. Microbial processes have caused an intriguing variability of the carbon isotopes in the calcites at all sites, with delta C-13 spanning as much as -93.1 parts per thousand (related to anaerobic oxidation of methane) to +36.5 parts per thousand (related to methanogenesis). Spatiotemporal coupling between the stable isotope measurements and radiometric age determinations (micro-scale dating using new high spatial methods: LA-ICP-MS U-Pb for calcite and Rb-Sr for calcite and co-genetic adularia) enabled unprecedented direct timing constraints of the microbial processes to several periods throughout the Phanerozoic eon, dating back to Devonian times. These events have featured variable fluid salinities and temperatures as shown by fluid inclusions in the calcite; dominantly 70-85 degrees C brines in the Paleozoic and lower temperatures (<50-62 degrees C) and salinities in the Mesozoic. Preserved organic compounds, including plant signatures, within the calcite crystals mark the influence of organic matter in descending surficial fluids on the microbial processes in the fracture system, thus linking processes in the deep and surficial biosphere. These findings substantially extend the recognized temporal and spatial range for production and consumption of methane within the upper continental crust. (C) 2017 Elsevier B.V. All rights reserved.

  • 27.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Heim, Christine
    Whitehouse, Martin
    Broman, Curt
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Episodic microbial methanogenesis, methane oxidation and sulfate reduction in deep granite fractures at Forsmark, Sweden2017In: 15TH WATER-ROCK INTERACTION INTERNATIONAL SYMPOSIUM, WRI-15 / [ed] Marques, JM Chambel, A, 2017, p. 702-705Conference paper (Refereed)
    Abstract [en]

    An extensive microanalytical isotope study of calcite and pyrite has been carried out in bedrock fractures at Forsmark, Sweden. The very large delta C-13(calcite)-variation of 103.4% V-PDB in total (-69.2 to +34.2%) evidences significant spatial and temporal variability in processes and carbon sources in the deep fracture system during the period when these minerals were formed (Phanerozoic). The substantial delta C-13(calcite)-span is mainly methane-related, with heavy and very light delta C-13 originating from ubiquitous in situ microbial methanogenesis and anaerobic oxidation of methane (AOM), respectively. Co-genetic cubic and framboidal pyrite showed substantial sulfate reducing bacteria (SRB)-related delta S-34 variation of 95% V-CDT overall (-29 to +66%), indicating closed system isotope distillation and point to similar genetic SRB methane-oxidizer relationships as in marine sediments. The depth distribution of the methanogenesis-, SRB- and AOM-signatures are from just below the ground surface down to about 800 m, which marks the deepest occurrence of AOM-related carbonate yet reported from the continental crystalline crust. Biomarkers and fluid inclusions suggest that the microbial activity in the bedrock fractures was closely related to descending surficial fluids and basinal brines rich in organic matter, in at least two pulses (70-80 degrees C and <50-62 degrees C). (C) 2017 Published by Elsevier B.V.

  • 28.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Ivarsson, Magnus
    Swedish Museum of Natural History.
    Bengtson, Stefan
    Swedish Museum of Natural History.
    Heim, Christine
    Georg-August University, Germany.
    Siljeström, Sandra
    SP Technical Research Institute of Sweden.
    Whitehouse, Martin J.
    Swedish Museum of Natural History.
    Broman, Curt
    Stockholm University.
    Belivanova, Veneta
    Swedish Museum of Natural History.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Anaerobic consortia of fungi and sulfate reducing bacteria in deep granite fractures2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, p. 1-9, article id 55Article in journal (Refereed)
    Abstract [en]

    The deep biosphere is one of the least understood ecosystems on Earth. Although most microbiological studies in this system have focused on prokaryotes and neglected microeukaryotes, recent discoveries have revealed existence of fossil and active fungi in marine sediments and sub-seafloor basalts, with proposed importance for the subsurface energy cycle. However, studies of fungi in deep continental crystalline rocks are surprisingly few. Consequently, the characteristics and processes of fungi and fungus-prokaryote interactions in this vast environment remain enigmatic. Here we report the first findings of partly organically preserved and partly mineralized fungi at great depth in fractured crystalline rock (−740 m). Based on environmental parameters and mineralogy the fungi are interpreted as anaerobic. Synchrotron-based techniques and stable isotope microanalysis confirm a coupling between the fungi and sulfate reducing bacteria. The cryptoendolithic fungi have significantly weathered neighboring zeolite crystals and thus have implications for storage of toxic wastes using zeolite barriers.

  • 29.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mathurin, Frédéric A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Bur Rech Geol & Minieres, France.
    Zack, Thomas
    University of Gothenburg.
    Schäfer, Thorsten
    Karlsruhe Inst Technol, Germany;Friedrich Schiller Univ Jena, Germany.
    Roberts, Nick
    British Geol Survey, UK.
    Whitehouse, Martin
    Swedish Museum of Natural History.
    Karlsson, Andreas
    Swedish Museum of Natural History.
    Broman, Curt
    Stockholm university.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Incorporation of Metals into Calcite in a Deep Anoxic Granite Aquifer2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 2, p. 493-502Article in journal (Refereed)
    Abstract [en]

    Understanding metal scavenging by calcite in deep aquifers in granite is of importance for deciphering and modeling hydrochemical fluctuations and water–rock interaction in the upper crust and for retention mechanisms associated with underground repositories for toxic wastes. Metal scavenging into calcite has generally been established in the laboratory or in natural environments that cannot be unreservedly applied to conditions in deep crystalline rocks, an environment of broad interest for nuclear waste repositories. Here, we report a microanalytical study of calcite precipitated over a period of 17 years from anoxic, low-temperature (14 °C), neutral (pH: 7.4–7.7), and brackish (Cl: 1700–7100 mg/L) groundwater flowing in fractures at >400 m depth in granite rock. This enabled assessment of the trace metal uptake by calcite under these deep-seated conditions. Aquatic speciation modeling was carried out to assess influence of metal complexation on the partitioning into calcite. The resulting environment-specific partition coefficients were for several divalent ions in line with values obtained in controlled laboratory experiments, whereas for several other ions they differed substantially. High absolute uptake of rare earth elements and U(IV) suggests that coprecipitation into calcite can be an important sink for these metals and analogousactinides in the vicinity of geological repositories.

  • 30.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Tullborg, Eva-Lena
    Terralogica AB, Gråbo, Sweden.
    Hogmalm, Johan
    Göteborgs universitet.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Trace metal distribution and isotope variations in low-temperature calcite and groundwaters in granitoid fractures down to 1 km depth2012In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 84, p. 217-238Article in journal (Refereed)
    Abstract [en]

    Studies of low-temperature fracture calcite in Proterozoic or Archaean crystalline rocks are very limited, mainly becausethis calcite usually is, first, not very abundant and second, very fine-grained or forms rims on older (and much more abundant)hydrothermal calcite and is thus difficult to distinguish. Knowledge of chemical characteristics and the correlation withgroundwater chemistry is thus scarce for low-temperature calcite in these settings, and consequently, knowledge of the recentpalaeohydrogeological history is limited. Boreholes drilled with triple-tube technique in the upper 1 km of the Palaeoproterozoiccrystalline crust at Laxemar, SE Sweden, have enabled preservation of fragile and potentially recently formed fractureminerals. Earlier investigations of these boreholes have resulted in an extensive set of groundwater chemistry data from variousdepths, and in detailed knowledge of the fracture mineral assemblages (ranging from 1.8 Ga to present). This has made itpossible to identify and sample low-temperature, potentially recently formed, calcite from water-flowing fractures for whichrepresentative groundwater chemical data exists. This, in turn, provides an opportunity to detailed comparisons of fracturecalcite (age span in the order of million years, with possibility of post-glacial contributes) and groundwater (age in the order ofdecades to more than a million year depending on depth) in terms of both isotopic and geochemical properties, giving input tothe understanding of groundwater history, partition coefficients derived in laboratory experiment, and reliability of calcitegeochemistry in terms of representing the actual source fluid composition. In this study, the focus is on trace elements (Fe,Mg, Mn and Sr), stable isotopes and Sr isotopes and, for the groundwater data set, also aquatic speciation with Visual MINTEQ.An optimised step-by-step sample specific analytical procedure was used for the collection of calcite coatings. The methodsused depended on the crystal homogeneity (one or several calcite generations), discerned by detailed SEM-investigations(back-scatter and cathodo-luminescence). 87Sr/86Sr ratios as well as d18O signatures in calcite are in the range expected for theprecipitates from present-day groundwater, or older groundwater with similar composition (except in sections with a considerableportion of glacial water, where calcite definitely is older than the latest glaciation). Stable carbon isotopes in calcitegenerally show values typically associated with HCO3 originating from soil organic matter but at intermediate depth frequentlywith HCO3 originating from in situ microbial anaerobic oxidation of methane (highly depleted d13C). For one ofthe studied metals – manganese – there was a strong correlation between the sampled calcite coatings and hypothetical calcitepredicted by applying laboratory-based partition coefficients (literature data) on groundwater chemistry for sections correspondingto those where the calcites were sampled. This points to temporal and spatial stability in groundwater Mn/Ca ratiosover millions of years, or even more, and show that it is possible to assess, based on laboratory-derived data on Mn partitioning,past groundwater Mn-composition from fracture calcites. For other metals – Fe, Sr, and Mg – which are expected to interact with co-precipitating minerals to a higher degree than Mn, the correlations between measured and predicted calcitewere weaker for various reasons.

  • 31.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tullborg, Eva-Lena
    Univ Gothenburg, Sweden.
    Whitehouse, Martin
    Swedish Museum Nat Hist, Sweden.
    Sandberg, Bertil
    Swerea KIMAB, Sweden.
    Blomfeldt, Thomas
    Swerea KIMAB, Sweden.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Extreme fractionation and micro-scale variation of sulphur isotopes during bacterial sulphate reduction in deep groundwater systems2015In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 161, p. 1-18Article in journal (Refereed)
    Abstract [en]

    This study conducted at the Aspo Hard Rock Laboratory, SE Sweden, determines the extent and mechanisms of sulphur-isotope fractionation in permanently reducing groundwater in fractured crystalline rock. Two boreholes > 400 m below the ground surface were investigated. In the 17-year-old boreholes, the Al instrumentation pipes had corroded locally (i.e., Al[oxy] hydroxides had formed) and minerals (i.e., pyrite, iron monosulphide, and calcite) had precipitated on various parts on the equipment. By chemically and isotopically comparing the precipitates on the withdrawn instrumentation and the borehole waters, we gained new insight into the dynamics of sulphate reduction, sulphide precipitation, and sulphur-isotope fractionation in deep-seated crystalline-rock settings. An astonishing feature of the pyrite is its huge variability in delta S-34, which can exceed 100 parts per thousand in total (i.e., -47.2 to +53.3 parts per thousand) and 60 parts per thousand over 50 mu m of growth in a single crystal. The values at the low end of the range are up to 71 parts per thousand lower than measured in the dissolved sulphate in the water (20-30 parts per thousand), which is larger than the maximum difference reported between sulphate and sulphide in pure-culture experiments (66 parts per thousand) but within the range reported from natural sedimentary settings. Although single-step reduction seems likely, further studies are needed to rule out the effects of possible S disproportionation. The values at the high end of the range (i.e., high delta S-34(py)) are much higher than could be produced from the measured sulphate under any biogeochemical conditions. This strongly suggests the development of closed-system conditions near the growing pyrite, i.e., the rate of sulphate reduction exceeds the rate of sulphate diffusion in the local fluid near the pyrite, causing the local aqueous phase (and thus the forming pyrite) to become successively enriched in heavy S (S-34). Consequently, the delta S-34 values of the forming pyrite become exceptionally high and strongly decoupled from the delta S-34 values of the sulphate in the bulk fluid. The Al-(oxy) hydroxide and calcite precipitates are explained by a combination of deposit and galvanic corrosion initiated by Al corrosion by H2S produced by sulphate-reducing microorganisms. (C) 2015 Elsevier Ltd. All rights reserved.

  • 32.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Whitehouse, Martin J.
    Swedish Museum of Natural History.
    Heim, Christine
    Georg August Univ, Germany.
    Reiners, Peter W.
    Univ Arizona, USA.
    Tillberg, Mikael
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogmalm, K. Johan
    University of Gothenburg.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Broman, Curt
    Stockholm University.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Unprecedented 34S-enrichment of pyrite formed following microbial sulfate reduction in fractured crystalline rocks2018In: Geobiology, ISSN 1472-4677, E-ISSN 1472-4669, Vol. 16, no 5, p. 556-574Article in journal (Refereed)
    Abstract [en]

    In the deep biosphere, microbial sulfate reduction (MSR) is exploited for energy. Here, we show that, in fractured continental crystalline bedrock in three areas in Sweden, this process produced sulfide that reacted with iron to form pyrite extremely enriched in S-34 relative to S-32. As documented by secondary ion mass spectrometry (SIMS) microanalyses, the S-34(pyrite) values are up to +132 parts per thousand V-CDT and with a total range of 186 parts per thousand. The lightest S-34(pyrite) values (-54 parts per thousand) suggest very large fractionation during MSR from an initial sulfate with S-34 values (S-34(sulfate,0)) of +14 to +28 parts per thousand. Fractionation of this magnitude requires a slow MSR rate, a feature we attribute to nutrient and electron donor shortage as well as initial sulfate abundance. The superheavy S-34(pyrite) values were produced by Rayleigh fractionation effects in a diminishing sulfate pool. Large volumes of pyrite with superheavy values (+120 +/- 15 parts per thousand) within single fracture intercepts in the boreholes, associated heavy average values up to +75 parts per thousand and heavy minimum S-34(pyrite) values, suggest isolation of significant amounts of isotopically light sulfide in other parts of the fracture system. Large fracture-specific S-34(pyrite) variability and overall average S-34(pyrite) values (+11 to +16 parts per thousand) lower than the anticipated S-34(sulfate,0) support this hypothesis. The superheavy pyrite found locally in the borehole intercepts thus represents a late stage in a much larger fracture system undergoing Rayleigh fractionation. Microscale Rb-Sr dating and U/Th-He dating of cogenetic minerals reveal that most pyrite formed in the early Paleozoic era, but crystal overgrowths may be significantly younger. The C-13 values in cogenetic calcite suggest that the superheavy S-34(pyrite) values are related to organotrophic MSR, in contrast to findings from marine sediments where superheavy pyrite has been proposed to be linked to anaerobic oxidation of methane. The findings provide new insights into MSR-related S-isotope systematics, particularly regarding formation of large fractions of S-34-rich pyrite.

  • 33.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Heim, Christine
    Univ Göttingen, Germany.
    Broman, Curt
    Stockholm Univ.
    Åstrom, Jan
    CSC IT Ctr Sci, Finland.
    Whitehouse, Martin
    Swedish Museum Nat Hist.
    Ivarsson, Magnus
    Swedish Museum Nat Hist.
    Siljeström, Sandra
    SP Tech Res Inst Sweden.
    Sjövall, Peter
    SP Tech Res Inst Sweden.
    Extreme C-13 depletion of carbonates formed during oxidation of biogenic methane in fractured granite2015In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 6, article id 7020Article in journal (Refereed)
    Abstract [en]

    Precipitation of exceptionally C-13-depleted authigenic carbonate is a result of, and thus a tracer for, sulphate-dependent anaerobic methane oxidation, particularly in marine sediments. Although these carbonates typically are less depleted in C-13 than in the source methane, because of incorporation of C also from other sources, they are far more depleted in C-13 (delta C-13 as light as - 69% V-PDB) than in carbonates formed where no methane is involved. Here we show that oxidation of biogenic methane in carbon-poor deep groundwater in fractured granitoid rocks has resulted in fracture-wall precipitation of the most extremely C-13-depleted carbonates ever reported, delta C-13 down to - 125% V-PDB. A microbial consortium of sulphate reducers and methane oxidizers has been involved, as revealed by biomarker signatures in the carbonates and S-isotope compositions of co-genetic sulphide. Methane formed at shallow depths has been oxidized at several hundred metres depth at the transition to a deep-seated sulphate-rich saline water. This process is so far an unrecognized terrestrial sink of methane.

  • 34.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tullborg, Eva-Lena
    Göteborgs universitet.
    Whitehouse, Martin
    Naturhistoriska riksmuseet.
    Activity of sulfur reducing bacteria in deep bedrock fractures revealed by variability of δ34S in pyrite and dissolved sulphate2013In: Procedia Earth and Planetary Science, ISSN 1878-5220, Vol. 7, p. 228-231Article in journal (Refereed)
    Abstract [en]

    Euhedral pyrite crystals coating 46 granite fractures at depths down to nearly 1 km at Laxemar, Sweden, were analysed for sulfur isotopes (δ34Spyr) by in situ SIMS (secondary ion mass spectrometry) analysis. Most of these fractures had corresponding chemical and isotopic groundwater data, providing a unique opportunity of pyrite-sulfate comparison within the same fracture network. Comparison of the isotopic ratios (δ18O, δ13C, 87Sr/86Sr) of co-genetic calcite with the groundwater showed that the sampled fractures carried pyrite and calcite that are of low-temperature origin, and with some exceptions, possibly precipitated from the present groundwater, or similar pre-modern fluids.

    The δ34Spyr showed huge variations across individual crystals (such as -32 to +73‰) and an extreme overall range (-50‰ to +91‰), which can only be explained by the activity of sulfur reducing bacteria (SRB). The most common sub-grain features were an increase in δ34Spyr with crystal growth related to successively higher δ34SSO4 caused by ongoing SRB activity and Rayleigh fractionation in fractures with low flow. The groundwater δ34SSO4 values (+9 to +37‰) are, in particular in the sulfate-poor waters down to -400 m, higher than the anticipated initial values, and this can also be explained by SRB-related Rayleigh distillation. The δ34SSO4 of the groundwater is, however, lower than that required to produce the highest δ34Spyr values, which may be due to the signal of groundwater in low-flow fractures (carrying 34S-rich sulfate and pyrite) being masked in the water data by high-flow parts of the water-flowing structure carrying abundant and less fractionated sulfate.

  • 35.
    Drake, Henrik
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tullborg, Eva-Lena
    Whitehouse, Martin
    Fallick, Anthony E.
    Variability of sulphur isotope ratios in pyrite and dissolved sulphate in granitoid fractures down to 1km depth - Evidence for widespread activity of sulphur reducing bacteria2013In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 102, p. 143-161Article in journal (Refereed)
    Abstract [en]

    Euhedral pyrite crystals in 46 open bedrock (granitoid) fractures at depths down to nearly 1 km were analysed for sulphur isotope ratios (delta S-34) by the in situ secondary ion mass spectrometry (SIMS) technique and by conventional bulk-grain analysis, and were compared with groundwater data. Twenty nine of the fractures sampled for pyrite had corresponding data for groundwater, including chemistry and isotopic ratios of sulphate, which provided a unique opportunity to compare the sulphur-isotopic ratios of pyrite and dissolved sulphate both at site and fracture-specific scales. Assessment of pyrite age and formation conditions were based on the geological evolution of the area (Laxemar, SE Sweden), and on data on co-genetic calcite as follows: (1) the isotopic ratios of the calcite crystals (delta O-18, delta C-13, Sr-87/Sr-86) were compared with previously defined isotopic features of fracture mineral assemblages precipitated during various geological periods, and (2) the delta O-18 of the calcites were compared with the delta O-18 of groundwater in fractures corresponding to those where the calcite/pyrite assemblages were sampled. Taken together, the data show that all the sampled fractures carried pyrite/calcite that are low-temperature and precipitated from the current groundwater or similar pre-existing groundwater, except at depths of -300 to -600 m where water with a glacial component dominates and the crystals are from pre-modern fluids. An age of <10 Ma are anticipated for the pre-modern fluids. The delta S-34(pyr) showed huge variations across individual crystals (such as -32 to +73 parts per thousand) and extreme minimum (-50 parts per thousand) and maximum (+91 parts per thousand) values. For this kind of extreme S-isotopic variation at earth-surface conditions there is no other explanation than activity of sulphur reducing bacteria coupled with sulphate-limited conditions. Indeed, the most common subgrain feature was an increase in delta S-34(pyr) values from interior to rim of the crystal, which we interpret are related to successively higher delta S-34 values of the dissolved source SO42- caused by ongoing bacterial sulphate reduction in fractures with low-flow or stagnant waters. The measured groundwater had delta S-34(SO4) values of +9 parts per thousand to +37 parts per thousand, with the highest values associated with low sulphate concentrations. These values are overall, and especially in the sulphate-poor waters down to -400 m, somewhat higher than the anticipated initial values, and can thus, like for the S-34-enriched pyrites, be explained by a Rayleigh distillation process driven by microbial sulphate reduction. An intriguing feature was that the delta S-34(SO4) values of the groundwater were in no case reaching up to the values required to produce biogenic pyrite with delta S-34 values of +40 parts per thousand to +91 parts per thousand. To explain this feature, we suggest that groundwater in low-flow fractures with near-stagnant water (carrying sulphate and pyrite with high delta S-34) is masked by high-flow parts of the fracture system carrying groundwater that often contains sulphate in abundance and considerably less fractionated with respect to S-34 and S-32. In order to gain detailed knowledge of chemical processes and patterns in groundwater in fractured rock, fracture-mineral investigations are a powerful tool, as we have shown here for the sulphur system. (C) 2012 Elsevier Ltd. All rights reserved.

  • 36.
    Forsman, Anders
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Berggren, Hanna
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Larsson, Per
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    To what extent can existing research help project climate change impacts on biodiversity in aquatic environments?: A review of methodological approaches2016In: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 4, no 4, article id 75Article, review/survey (Refereed)
    Abstract [en]

    It is broadly accepted that continued global warming will pose a major threat to biodiversity in the 21st century. But how reliable are current projections regarding consequences of future climate change for biodiversity? To address this issue, we review the methodological approaches in published studies of how life in marine and freshwater environments responds to temperature shifts. We analyze and compare observational field surveys and experiments performed either in the laboratory or under natural conditions in the wild, the type of response variables considered, the number of species investigated, study duration, and the nature and magnitude of experimental temperature manipulations. The observed patterns indicate that, due to limitations of study design, ecological and evolutionary responses of individuals, populations, species, and ecosystems to temperature change were in many cases difficult to establish, and causal mechanism(s) often remained ambiguous. We also discovered that the thermal challenge in experimental studies was 10,000 times more severe than reconstructed estimates of past and projections of future warming of the oceans, and that temperature manipulations also tended to increase in magnitude in more recent studies. These findings raise some concerns regarding the extent to which existing research can increase our understanding of how higher temperatures associated with climate change will affect life in aquatic environments. In view of our review findings, we discuss the trade-off between realism and methodological tractability. We also propose a series of suggestions and directions towards developing a scientific agenda for improving the validity and inference space of future research efforts.

  • 37. Fältmarsch, R
    et al.
    Peltola, Pasi
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Raitio, H
    Abundance, correlations and spatial patterns of nutrients and metals in till, humus, moss and pine needles in a boreal forest, western Finland2007In: Geochemistry: Exploration, Environment, Analysis, ISSN 1467-7873, E-ISSN 2041-4943, Vol. 7Article in journal (Refereed)
  • 38. Fältmarsch, R
    et al.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Vuori, K
    Effect of toxic metals mobilised from Finnish acid sulphate soils on terrestrial and aquatic biota: a literature review2008In: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 13, p. 444-456Article in journal (Refereed)
  • 39. Fältmarsch, Rasmus
    et al.
    Österholm, Peter
    Greger, Maria
    Åström, Mats E.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Metal concentrations in oats (Avena sativa L.) grown on acid sulphate soils2009In: Agricultural and Food Science, ISSN 1459-6067, E-ISSN 1795-1895, Vol. 18, no 1, p. 45-56Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate the impact of soil chemistry on the concentrations of Co, Ni, Zn, Mn, Cu and Fe in oats (Avena saliva L. cv. Fiia) grown on Finnish acid sulphate (AS) soils with varying geochemical characteristics. Twenty two soil profiles, which were sampled to a depth of 1 m (five 20 cm section splits), and 26 composite oat grain samples were collected on a total of five fields. The concentrations of Co, Ni, Zn and Mn in the grains were correlated with the NH(4)Ac-EDTA-extractable concentrations in the soils. However, as these four chalcophilic metals are in general easily lost to drains and not retained as a large pool in the soil in easily-extractable form, also the concentrations in the oats were not in general elevated as compared with average values on other soils. On one of the fields, however, the Co and Ni concentrations in the soil, and thus also in the oats, were clearly elevated. Copper and Fe displayed no correlation between the soil and oat concentrations, indicating that the plant-uptake mechanisms are much more important than variations in geochemistry. It was suggested that the NH(4)Ac-EDTA solution was not efficient in extracting Fe and Cu, which shows that these metals are bound in relatively immobile oxyhydroxides.

  • 40.
    Lavergren, Ulf
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats E.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Bergbäck, Bo
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Holmström, Henning
    Mobility of trace elements in black shale assessed by leaching tests and sequential chemical extraction2009In: Geochemistry: Exploration, Environment, Analysis, ISSN 1467-7873, E-ISSN 2041-4943, Vol. 9, p. 71-79Article in journal (Refereed)
    Abstract [en]

    This study focuses on the abundance and mobility of Ca, Fe, S and trace elements (As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, U, V and Zn) in black shale (alum shale) in SE, Sweden. Samples of non-weathered, weathered and burnt black shale were chemically characterized and the potential element release from them was assessed by standard water-based leaching tests and pH/redox-regulated availability tests. Sequential chemical extractions provided further information on the phases in which the elements are bound. Results show that the shale is very rich in As (88-122 ppm), Cd (0.4-4.6 ppm), Mo (61-176 ppm), U (27-71 ppm) and V (496-1560 ppm). Cadmium and Mo, bound mainly in sulphides or organic matter, are very mobile in the non-burnt shale, with mobilization rates of up to 19% (190 mu g/kg) and 25% (16 mg/kg), respectively, using only water as extraction medium. The non-weathered shale is also relatively rich in Cu (113 ppm), Ni (100 ppm) and Zn (304 ppm), the latter two in particular showing behaviour similar to that of Cd, but with lower mobilization rates. In all samples U and V arc found mainly in weathering-resistant mineral phases and thus have a lower mobility, but due to the high abundance in the material, significant amounts of U can be released on longer time scales (up to 6 mg/kg, as indicated by the pH/redox-regulated test). Less than 1% of the As is released in all the leaching tests, indicating that upon oxidation it is retained in the solid phase. The overall conclusion is that this material has a high potential for releasing Cd, Mo, Ni, U and Zn (luring weathering.

  • 41.
    Lavergren, Ulf
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats E.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Falk, Helena
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Bergbäck, Bo
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Metal dispersion in groundwater in an area with natural and processed black shale - Nationwide prespective and comparison with acid sulfate soils2009In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 24, no 3, p. 359-369Article in journal (Refereed)
    Abstract [en]

    Black shale is often rich in sulfides and trace elements, and is thus a potential environmental threat in a manner similar to acid sulfate soils and active or abandoned sulfide mines. This study aims at characterising how exposed and processed (mined and burnt) black shale (alum shale) in Degerhamn, SE Sweden, affects the chemistry (Al, As, Ba, Cd, Ca, Cr, Co, Cu, Fe, Pb, Mg, Mn, Mo, Ni, K, Si, Na, Sr, S, U, V and Zn) of the groundwater. There were large variations in groundwater chemistry between nearby sampling points, while the temporal variations generally were small. Acidic groundwater (around pH 4), found in deposits of burnt and carbonate-poor shale where the conditions for sulfide oxidation were favourable, was strongly elevated in Al, U and several chalcophilic metals (Cd, Co, Cu, Ni and Zn). Cadmium and U were also, together with Mo, abundant in many of the near-neutral waters, both in the non-mined black shale bedrock and in the deposits of burnt shale. An extrapolation to a national level suggests that the dispersion of Ni from naturally occurring black shale is similar to that from anthropogenic point sources, while for Cd and As it is assessed to be approximately one tenth of that from point sources. The processed shale was, however, a much larger source of metals than the black shale bedrock itself, showing this material's potential as a massive supplier of metals to the aquatic environment. A comparison of waters in contact with the processed Cambrian-Ordovician black shale in Degerhamn and acid sulfate soils of the region shows that these two sulfide-bearing materials, in many respects very different, delivers basically the same suite of trace elements to the aquatic environment. This has implications for environmental planning and protection in areas where these types of materials exist.

  • 42.
    Lindell, Lina
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Henningsson, Marianne
    Linnaeus University, Faculty of Health and Life Sciences, Department of Psychology.
    Marquardt, Kristina
    Swedish University of Agricultural Sciences, Uppsala.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Farmers´(local and colonists) perceptions of environmental changes in the forest frontier of the upper Amazon, Peru2014In: International Journal of Agricultural Resources, Governance and Ecology, ISSN 1462-4605, E-ISSN 1741-5004, Vol. 10, no 4, p. 394-418Article in journal (Refereed)
    Abstract [en]

    Amazon ecosystem degradation profoundly impacts life supporting processes of global importance such as climate regulation, as well as localconditions for livelihoods. In Peru’s highland jungle, an expanding deforestationfront of forest conversion to agriculture has vastly transformed the landscape.

    Small-scale farming, the main driver of forest degradation, and consequently household natural resource management affect ecosystem functionality.To investigate farmers’ attitudes and priorities to services provided by the ecosystems (ES) we interviewed 51 farmers, both local and colonists. They strongly agreed that over the last three decades, local conditions for livelihoods have deteriorated following forest degradation and climate change. The latterwas reported the primary contributor to an impaired life quality and their greatest concern. Overall, local farmers perceived greater than did colonists who were also more positive towards intensive agricultureand forestry. This should be considered in environmental conservation efforts in the upper Amazon.

  • 43.
    Lindell, Lina
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Los Efectos de la Agricultura de Tala y Quema sobre la Fertilidad de los Suelos de la Amazonia Subandina, Perú2008Conference paper (Refereed)
  • 44.
    Lindell, Lina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Sarenbo, Sirkku
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Effects of forest slash and burn on the distribution of trace elements in floodplain sediments and mountain soils of the Subandean Amazon, Peru2010In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 25, no 8, p. 1097-1106Article in journal (Refereed)
    Abstract [en]

    Forest clearing through slash and burn to open up agricultural land is an ongoing process in large parts of the Amazon Basin. This activity severely affects the structure and balance of the natural ecosystem, and also has the potential to cause substantial changes in landscape geochemistry. The latter is the topic of this study, with special attention on translocation of potentially toxic trace elements from deforested areas to downstream aquatic and terrestrial systems. Sampling of floodplain sediments and mountain soils (Inceptisols on redbed lithologies) was carried out in two adjacent Subandean river basins, with deforestation extents of ca. 1/3 and 2/3 of the basin areas. Several 'toxic and potentially toxic metals (e.g., Hg, Cd, Pb, Cu and Ni) and other major and minor elements showed concentration peaks at certain depths in the alluvial deposits of both basins. These peaks were associated with organic matter, and occurred just below layers of combustion residues originating from burning of in situ biomass. Downward migration of particles originating in the combustion residues is suggested to be the direct mechanisms of the metal enrichments. Further evidence of an in situ origin of the metal peaks in the sediments was provided by the geochemical composition of soils located upstream of the floodplains. Disturbed soils (i.e. soils of pasture, coffee plantations, secondary forest and recently swidden fields) were found to be similar to soils under natural forest. Moreover, trace element concentrations in floodplain deposits were similar in the two drainage basins despite the large difference in exploitation degree. Thus, no evidence was found of large scale (basin-wide) increases in trace-metal leaching or translocation as a result of the extensive deforestation and agricultural land-use that has been practiced in the Amazonian highland jungle over more than 100 a.

  • 45.
    Lindell, Lina
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Åström, Mats E.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Öberg, Tomas
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Effects of land use change vs natural control on stream water chemistry in the subandean Amazon, Peru.2009In: Proceedings of XII Brazilian Congress on Geochemistry and VIII International Symposium on Environmental Geochemistry. Oct 18-22, Ouro Preto, Brazil., 2009Conference paper (Refereed)
  • 46.
    Lindell, Lina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Öberg, Tomas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Land-use change versus natural controls on stream water chemistry in the Subandean Amazon, Peru2010In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 25, no 3, p. 485-495Article in journal (Refereed)
    Abstract [en]

    This study evaluates the effects of deforestation and land-use change, as compared to natural controls, on stream water chemistry in the Subandean Amazon Dissolved major and trace elements were determined near the stream outlet of 48 independent watersheds with varying morphology. bed rock composition and intactness of forest cover (pristine to highly exploited) Geomorphological characteristics were derived from a digital elevation model, geological formations from digitalized maps and forest cover from digital classification of SPOT satellite images Partial least square regression and multiple linear regression showed that watershed average elevation, which ranged between 396 and 1649 m, was the strongest control on stream water chemistry, explaining >70% of the variation in K and a considerable part also for Mn, U, Mg and HCO3 with near exponential concentration increases down the altitude gradient Forest cover, which ranged between 7% and 99%, correlated strongly with average elevation (Spearman correlation coefficient, r(s) = 0.8), but had no statistically significant impact on stream solute concentrations Thus, in the studied Subandean region, watershed scale deforestation has not resulted in measurable impacts oil stream water chemistry which is dominated by the spatial variation in natural controls.

  • 47.
    Lindell, Lina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Öberg, Tomas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Land-use versus natural controls on soil fertility in the Subandean Amazon, Peru.2010In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 408, no 4, p. 965-975Article in journal (Refereed)
    Abstract [en]

    Deforestation to amplify the agricultural frontier is a serious threat to the Amazon forest. Strategies to attain and maintain satisfactory soil fertility, which requires knowledge of spatial and temporal changes caused by land-use, are important for reaching sustainable development. This study highlights these issues by evaluating the relative effects of agricultural land-use and natural factors on chemical fertility of inceptisols on redbed lithologies in the Subandean Amazon. Macro and micronutrients were determined in topsoil and subsoil in the vicinity of two villages at a total of 80 sites including pastures, coffee plantations, swidden fields, secondary forest and, as a reference, adjacent primary forest. Differences in soil fertility between the land cover classes were investigated by principal component analysis (PCA) and partial least squares regression (PLSR). Primary forest soil was found to be chemically similar to that of coffee plantations, pastures and secondary forests. There were no significant differences between soils of these land cover types in terms of plant nutrients (e.g. N, P, K, Ca, Mg, Mo, Mn, Zn, Cu and Co) or other fertility indicators (OM pH,, BS, EC, CECe and exchangeable acidity). The parent material (as indicated by texture and sample geographical origin) and the slope of the sampled sites were stronger controls on soil fertility than land cover type. Elevated concentrations of a few nutrients (NO3 and K) were, however detected in soils of swidden fields. Despite being fertile (higher CECe, Ca and P) compared to Oxisols and Ultisols in the Amazon lowland, the Subandean soils frequently showed deficiencies in several nutrients (e.g. P, K, NO3, Cu and Zn), and high levels of free Al at acidic sites. This paper concludes that deforestation and agricultural land-use has not introduced lasting chemical changes in the studied Subandean soils that are significant in comparison to the natural variability.

  • 48. Macdonald, B.C.T.
    et al.
    White, i
    Åström, Mats
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Keene, A.F.
    Melville, M.D.
    Reynolds, M.D.
    Discharge of weathering products from acid sulfate soils after a rainfall event, Tweed River, eastern Australia2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, p. 2695-2701Article in journal (Refereed)
  • 49.
    Maskenskaya, Olga
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogmalm, Johan
    University of Gothenburg.
    Fallick, Anthony
    Scottish Universities Environmental Research Centre.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Abundance and fractionation of rare earth elements in Ca/Al silicate-, calcite-, and fluorite-bearing hydrothermal veins related to Mesoproterozoic anorogenic fluorine-rich granitic intrusionsManuscript (preprint) (Other academic)
  • 50.
    Maskenskaya, Olga
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Drake, Henrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogmalm, Johan
    University of Gothenburg.
    Fallick, Anthony
    Scottish Universities Environmental Research Centre.
    Åström, Mats E.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Source and fractionation of rare earth elements and yttrium in Paleozoic multi-mineral veins in crystalline bedrock on the Baltic ShieldManuscript (preprint) (Other academic)
123 1 - 50 of 128
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