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  • 301.
    Hellqvist, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Reconstructing environment and human impact during 1500 years of mining activity around FalunCopper mine, Sweden, through a multidisciplinary approach2013In: Environmental and Archaeological Science Conference: AEA & UKAS 2013 Cardiff University 11th-14th April 2013, 2013Conference paper (Refereed)
    Abstract [en]

    Mining impact on the surrounding environment is one of the most severe human activities. The time the mining has been lasting is usually proportional to and increases the impact on the surrounding environment. In the interdisciplinary project presented in this paper, ”Falun above from Falun under”, is the earliest history from around 1300-1500 BP studied together with the increasing environmental impact of growing mining activity around Falun Copper mine. The environmental and cultural development is followed forward until the mine is lastly abandoned in 1992.

    The projects aim is to study the area unbiased and explore previous reference as well as initiating new investigations. The project use the British project ”Great Yarmouth Archaeological map project” as a model. Falun Copper mine have a central and in time long part in Sweden and was 2001 established as a UNESCO World Heritage and is therefore in some parts rather well studied –primarily in archaeology, earth science and history. Within the project today is several methods used and under development: sedimentological mapping, reconstruction and analysis; insect and pollen analysis; dendrochronology; GIS; archive material and previous archaeological and geotechnical reports etc. There are also studies connected to preservation (World Heritage) and environmental history pedagogy and didactics.

  • 302.
    Hellqvist, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Johansson, Jenny
    Almgren, Elisabeth
    Traustadottir, Ragnheidur
    Environmental and climatic changes during the late Holocene in Hjaltadalur, Skagafjörður, northern Iceland, interpreted from peat core analyses and pollen identification2016In: Theme B - Landscape Historical Ecology and Climate Change: B1 Land-use and Anthropogenic Land-cover Change over the Holocene - Information of Value for Climate and Environmental Research, 2016Conference paper (Refereed)
    Abstract [en]

    A landscape analysis based on a combination of several proxies including pollen analysis, loss on ignition, radiocarbon dating, sediment analysis and tephra analysis was undertaken on samples from Hjaltadalur, northern Iceland. The central settlement in the valley, Hólar, is an important site that was once the religious and cultural centre of northern Iceland. Sampling was done in wetlands and one mire (Viðvik) was chosen as the main study site for sampling and analyses. The results provide useful information and insights into temperature fluctuations and climatic development during the late Holocene. In the pollen record there is a transition from a warm and dry forest-like landscape to a cooler, more humid, open landscape during the last 5000 years, with a marked shift from a warm and dry to a cool and humid climate around 2500 years ago. Human activities are reflected by a distinct peak in the Compositae-pollen curve in the uppermost sequence of the sediment core that is indicative of the settlement period during the years AD 870-930. The climatic transition, which contributed to a reduction of the birch population, started before human settlement and the Landnám period (AD 870-930) and thus implies that humans were not solely responsible for the birch decline and the transition of the landscape from forest-like conditions to a more open environment, although the subsequent Viking Age and later settlements continued the afforestation trend.

  • 303.
    Hellqvist, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Lundqvist, Jennie
    Hedmark, Mia
    Developing Earth Science education research2014In: 31st Nordic Geological Winter Meeting. Lund, Sweden, January 8-10 2014. Scientific program: Outreach and Education: Reaching out with WOW to the many, Lund: Geologiska Föreningen , 2014, p. 167-167Conference paper (Refereed)
    Abstract [en]

    This paper presents an attempt to build up research within the field earth science education, presenting results from interview studies on the student’s experience of participation to Earth science (1st year earth science students), inventory on previous research, interviews of primary school pupils and a public survey of knowledge in earth science. In Sweden, there is almost no research on Earth science education, the field within science education concerning Earth Science. In both European and international perspective this is in opposite to Physics, Computer science, Chemistry and Biology. Also in an international perspective the published research on Earth science education is very low, with one exceptional exception in North America where there is a lot of research in science education of different subjects. The largest number of publications is, therefore, also published in North America. The subjects of highest interest in previous earth science education research are on questions about misconceptions, concept inventories and field related education, where virtual field studies is of special interest.

    In the attempt to build up research, focus is primarily on education and teaching in university studies, but pre-university studies (primary & secondary school; upper secondary school) and the public knowledge on Earth science are also of interest. The studies focus on: experience of participation (i.e. identity); managing difficult and/or advanced questions; misconceptions; education in particular fields, especially field studies and laboratory work. Methodological the research is mainly performed through quantitative and qualitative data analysis, case study research and phenomenographic approaches.

  • 304.
    Henderiks, Jorijntje
    Stockholm University.
    Coccolithophore size rules — Reconstructing ancient cell geometry and cellular calcite quota from fossil coccoliths2008In: Marine Micropaleontology, ISSN 0377-8398, E-ISSN 1872-6186, Vol. 67, no 1-2, p. 143-154Article in journal (Refereed)
  • 305.
    Henderiks, Jorijntje
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Size of marine phytoplankton: Why does it matter?2011Conference paper (Other academic)
    Abstract [en]

    Marine phytoplankton, such as diatoms and coccolithophores, constitute the base of the marine food chain and are a fundamental component in biogeochemical cycles. The overall ecological success of marine phytoplankton, but also its taxonomic diversity and size distribution, determines the efficiency by which fixed carbon is transferred to higher trophic levels and into the deep ocean- and sedimentary carbon reservoirs. In recent years, several hypotheses have been invoked to explain distinct macroevolutionary decreases in the cell size of phytoplankton during the Cenozoic. Global, long-term cooling has been cast a major role in driving these cell size decreases. Despite overall correspondence between long-term trends, however, it's becoming more and more clear that not all phytoplankton dance to the same tune. The latter is particularly evident when looking at different coccolithophore lineages. Here, I will review the state-of-the-art and highlight some open avenues that are worth exploring.

  • 306.
    Henderiks, Jorijntje
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Hannisdal, Bjarte
    Centre for Geobiology, Dept. of Earth Sciences, University of Bergen, N.
    Liow, Lee Hsiang
    CEES, Dept. of Biology, University of Oslo, N.
    Calcifying phytoplankton biomass and CO2: A striking balance2010Conference paper (Other academic)
  • 307.
    Henderiks, Jorijntje
    et al.
    Stockholm University.
    Pagani, Mark
    Coccolithophore cell size and the Paleogene decline in atmospheric CO22008In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 269, no 3-4, p. 576-584Article in journal (Refereed)
  • 308.
    Henderiks, Jorijntje
    et al.
    Stockholm University.
    Pagani, Mark
    Refining ancient carbon dioxide estimates: Significance of coccolithophore cell size for alkenone-based pCO2 records2007In: Paleoceanography, ISSN 0883-8305, E-ISSN 1944-9186, Vol. 22, no 3, p. PA3202-Article in journal (Refereed)
  • 309.
    Henderiks, Jorijntje
    et al.
    Stockholm University.
    Rickaby, Rosalind E. M.
    Dept. of Earth Sciences, Oxford University, UK.
    A coccolithophore concept for constraining the Cenozoic carbon cycle2007In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 4, no 3, p. 323-329Article in journal (Refereed)
  • 310.
    Herbert, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Seasonal variations in the composition of mine drainage-contaminated groundwater in Dalarna, Sweden2006In: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 90, no 3, p. 197-214Article in journal (Refereed)
    Abstract [en]

    Groundwater down-gradient from a mine rock dump in Dalarna, Sweden was sampled from the onset of snowmelt runoff (April) until October in order to investigate seasonal variations in groundwater composition. The results demonstrate that considerable variation in solute concentration (Al, Cu, Fe, SO42-, Zn) and acidity occurs in groundwater; the greatest change in solute concentrations occurs during the melting of the snow cover, when sulfide oxidation products are flushed from the rock dump. During this period, groundwater flow is concentrated near the soil surface with an estimated velocity of 1 m/day. Groundwater acidity varied by a factor of four closest to the rock dump during the sampling period, but these variations were attenuated with distance from the rock dump. Over a distance of 145 in, groundwater pH increases from 2.5 to 4.0 and acidity decreases from 3-13 to 0.8-1.1 meq/L, which is the combined effect of ferric iron precipitation and aluminosilicate weathering. As a result of flushing from the upper soil horizons, peaks in total organic carbon and ammonium concentrations in groundwater are observed at the end of snowmelt. In soils impacted by acidic surface runoff, the sequential extraction of C horizon soils indicates the accumulation of Cu in well-crystallized iron oxyhydroxides in the upper C horizon, while Cu, Fe, Ni and Zn accumulate in a well-crystallized iron oxyhydroxide hardpan that has formed 2.5m below the ground surface. Surface complexation modeling demonstrates that SO42- and Cu adsorb to the abundant iron oxyhydroxides at pH < 4, while Zn adsorption in this pH range is minimal.

  • 311.
    Holmgren, Bror
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Soil organic carbon pools of the Torneträsk catchment area: The importance of soil depth and stone and boulder content for carbon inventories in formerly glaciated subarctic soils2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    High latitude soils are estimated to store a considerable part of the global pool of soil organic carbon (SOC). Studies of global and regional SOC pools have estimated total inventories in northern Sweden’s subarctic region to fall within 10-50 kg m-2. However, correction factors for stone and boulder content of soils are often overlooked in SOC-studies and soil profiles are commonly normalized to a depth of 1 m, which can result in substantial overestimates of the SOC pool if a large part of the soil volume is occupied by stones/boulders or if the soil depth is shallower than 1 m. This study was performed to quantify SOC in soils of the Torneträsk catchment area using detailed measures of soil depth and stone/boulder contents. Two non-destructive sampling methods, ground penetrating radar (GPR) and rod penetration, were used to measure soil depth and stone and boulder content in the catchment area. Results show that average soil depth (n = 52344) varied between 0.95 – 2.14 m depending on elevation and the average mire depth was 0.63 m. Stone and boulder content of the soil was estimated to 49 – 68 % depending on elevation. The results were added to existing carbon and soil density data from the Torneträsk catchment area and total SOC inventories were calculated to 6.8 – 13.1 kg m-2. The results of this study indicate that previous studies on regional and global scale may have overestimated the SOC pools in the subarctic regions of northern Sweden.

  • 312.
    Holmgren, Bror
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tracing the source of colourless carbon in an arctic lake on SW Greenland: Insights of organic matter origin from hydrogen isotope analyses of samples prepared using steam equilibration2016Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Lakes play an important role in the global carbon (C) cycle as they process carbon from terrestrial (allochthonous) and within lake (autochthonous) sources and may store C over long periods of time. Some arctic lakes contain high concentrations of dissolved organic carbon (DOC) that does not absorb light and thus remains colourless. The origin of this DOC remains unknown, but the sediment of these lakes have been suggested to accumulate primarily autochthonous (algal) C. I developed an experimental chamber for hydrogen (H) isotope pre-treatments and applied a novel H isotope tracing approach to determine the origin of the DOC and sediment C of a lake on SW Greenland known to contain colourless DOC. I hypothesized that autochthonous C was the prime source of DOC and sediment C, in line with previous theories. Analyses of algae and soil samples from the catchment revealed that local allochthonous and autochthonous C sources had a δ2H composition of -139 ‰ and -209 ‰, respectively. In contrast to my hypothesis, the analysed DOC had a mean δ2H isotopic composition of -147 ‰ indicating a dominance (ca 80-90 %) of allochthonous C. Similarly, the sediment had a mean δ2H isotopic composition of -155 ‰, suggesting that about 84 % of the C accumulating in the sediment was derived from terrestrial sources. The terrestrial origin was supported by field observations of high DOC seepage water (up to 70 mg L-1) with uncharacteristically low light absorption values entering the lake during high precipitation events. My results indicate that terrestrial processes are fundamental C sources for arctic lakes, even in regions with very low precipitation.

  • 313.
    Horemuz, Milan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Gajdamiwicz, Krzysztof
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Geodesy (closed 20110301).
    Integration of digital camera with INS2005Conference paper (Refereed)
  • 314.
    Hossain, Mohammed
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Sustainable Arsenic Mitigation A Strategy for Scaling-up Safe Water Access: A Strategy for Scaling-up Safe Water Access2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In rural Bangladesh, the drinking water supply is mostly dependent upon manually operated hand pumped tubewells, installed by the local community. The presence of natural arsenic (As) in groundwater and its wide scale occurrence has drastically reduced the safe water access across the country and put tens of millions of people under health risk. Despite significant progress in understanding the source and distribution of As and its mobilization through sediment-water interactions, there has been limited success in mitigation since the problem was discovered in the country’s water supply in 1993. This study evaluated the viability of other kinds of alternative safe drinking water options and found tubewells are the most suitable due to simplicity and technical suitability, a wide acceptance by society and above all low cost for installation, operation and maintenance. During planning and decision making in the process of tubewell installation, depth of the tubewell is a key parameter as it is related to groundwater quality and cost of installation. The shallow wells (usually < 80m) are mostly at risk of As contamination. One mitigation option are deep wells drilled countrywide to depths of around 250 m. Compared to safe water demand, the number of deep wells is still very low, as the installation cost is beyond affordability of the local community, especially for the poor and disadvantaged section of the society. Using depth-specific piezometers (n=82) installed in 15 locations spread over the 410 km2 area of Matlab (an As-hot spot) in southeastern Bangladesh, groundwater monitoring was done over a 3 year period (pre- and post-monsoon for 2009-2011 period). Measurements were performed for hydrogeological characterization of shallow, intermediate deep and deep aquifer systems to determine the possibility of targeting safe aquifers at different depths as the source of a sustainable drinking water supply. In all monitoring piezometers, As was found consistently within a narrow band of oscillation probably due to seasonal effects. Hydrogeochemically, high-As shallow groundwaters derived from black sands are associated with elevated DOC, HCO3, Fe, NH4-N and PO4-P and with a relatively low concentration of Mn and SO4. Opposite to this, shallow aquifers composed of red and off-white sediments providing As-safe groundwater are associated with low DOC, HCO3, Fe, NH4-N and PO4-P and relatively higher Mn and SO4. Groundwaters sampled from intermediate deep and deep piezometers which were found to be low in As, are characterized by much lower DOC, HCO3, NH4-N and PO4-P compared to the shallow aquifers. Shallow groundwaters are mostly Ca-Mg-HCO3 type and intermediate deep and deep aquifers’ groundwaters are mostly Na-Ca-Mg-Cl-HCO3 to Na-Cl-HCO3 type.

    A sediment color tool was also developed on the basis of local driller’s color perception of sediments (Black, White, Off-white and Red), As concentration of tubewell waters and respective color of aquifer sediments. A total of 2240 sediment samples were collected at intervals of 1.5 m up to a depth of 100 m from all 15 nest locations. All samples were assigned with a Munsell color and code, which eventually led to identify 60 color varieties. The process continued in order to narrow the color choices to four as perceived and used by the local drillers for identification of the targeted As-safe aquifers. Munsell color codes assigned to these sediments render them distinctive from each other which reduces the risk for misinterpretation of the sediment colors. During the process of color grouping, a participatory approach was considered taking the opinions of local drillers, technicians, and geologists into account. In addition to the monitoring wells installed in the piezometer nests, results from 87 other existing drinking water supply tubewells were also considered for this study. A total of 39 wells installed in red sands at shallow depths producing As-safe water providing strong evidence that red sediments are associated with As-safe water. Average and median values were found to be less than the WHO guideline value of 10 μg/L. Observations for off-white sediments were also quite similar. Targeting off-white sands could be limited due to uncertainty of proper identification of color, specifically when day-light is a factor. Elevated Mn in red and off-white sands is a concern in the safe water issue and emphasizes the necessity of a better understanding of the health impact of Mn. White sediments in shallow aquifers are relatively uncommon and seemed to be less important for well installations. Arsenic concentrations in more than 90% of the shallow wells installed in black sands are high with an average of 239 μg/L from 66 wells installed in black sediments. It is thereby recommended that black sands in shallow aquifers must be avoided. This sediment color tool shows the potential for enhancing the ability of local tubewell drillers for the installation of As-safe shallow drinking water tubewells.

    Considering the long-term goal of the drinking water safety plan to provide As-safe and low-Mn drinking water supply, this study also pioneered hydrogeological exploration of the intermediate deep aquifer (IDA) through drilling up to a depth of 120 m. Clusters of tubewells installed through site optimization around the monitoring piezometer showed a similar hydrochemical buffer and proved IDA as a potential source for As-safe and low-Mn groundwater. Bangladesh drinking water standard for As (50 µg/L) was exceeded in only 3 wells (1%) and 240 wells (99%) were found to be safe. More than 91% (n=222) of the wells were found to comply with the WHO guideline value of 10 µg/L. For Mn, 89% (n=217) of the wells show the concentration within or below the previous WHO guideline value of 0.4 mg/L, with a mean and median value of 0.18 and 0.07 mg/L respectively. The aquifer explored in the Matlab area shows a clear pattern of low As and low Mn. The availability of similar sand aquifers elsewhere at this depth range could be a new horizon for tapping safe drinking water at about half the cost of deep tubewell installation.

    All findings made this study a comprehensive approach and strategy for replication towards As mitigation and scaling-up safe water access in other areas of Bangladesh and elsewhere having a similar hydrogeological environment.

  • 315.
    Hotchkiss, E. R.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hall, R. O., Jr.
    Sponseller, R. A.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Butman, D.
    Klaminder, J.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Laudon, H.
    Rosvall, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Karlsson, J.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sources of and processes controlling CO2 emissions change with the size of streams and rivers2015In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 8, no 9, p. 696-699Article in journal (Refereed)
    Abstract [en]

    Carbon dioxide (CO2) evasion from streams and rivers to the atmosphere represents a substantial flux in the global carbon cycle(1-3). The proportions of CO2 emitted from streams and rivers that come from terrestrially derived CO2 or from CO2 produced within freshwater ecosystems through aquatic metabolism are not well quantified. Here we estimated CO2 emissions from running waters in the contiguous United States, based on freshwater chemical and physical characteristics and modelled gas transfer velocities at 1463 United States Geological Survey monitoring sites. We then assessed CO2 production from aquatic metabolism, compiled from previously published measurements of net ecosystem production from 187 streams and rivers across the contiguous United States. We find that CO2 produced by aquatic metabolism contributes about 28% of CO2 evasion from streams and rivers with flows between 0.0001 and 19,000 m(3) s(-1). We mathematically modelled CO2 flux from groundwater into running waters along a stream-river continuum to evaluate the relationship between stream size and CO2 source. Terrestrially derived CO2 dominates emissions from small streams, and the percentage of CO2 emissions from aquatic metabolism increases with stream size. We suggest that the relative role of rivers as conduits for terrestrial CO2 efflux and as reactors mineralizing terrestrial organic carbon is a function of their size and connectivity with landscapes.

  • 316.
    Hotchkiss, Erin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Program in Ecology and Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA.
    Hall, R. O., Jr.
    Baker, M. A.
    Rosi-Marshall, E. J.
    Tank, J. L.
    Modeling priming effects on microbial consumption of dissolved organic carbon in rivers2014In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 119, no 5, p. 982-995Article in journal (Refereed)
    Abstract [en]

    Rivers receive and process large quantities of terrestrial dissolved organic carbon (DOC). Biologically available (unstable) DOC leached from primary producers may stimulate (i.e., prime) the consumption of more stable terrestrially derived DOC by heterotrophic microbes. We measured microbial DOC consumption (i.e., decay rates) from contrasting C sources in 10 rivers in the western and Midwestern United States using short-term bioassays of river water, soil and algal leachates, glucose, and commercial humate. We added inorganic nutrients (ammonium and phosphorus) to a subset of bioassays. We also amended a subset of river, soil, and commercial humate bioassays with glucose or algal leachates to test the hypothesis that unstable DOC primes consumption of more stable DOC. We used prior measurements of source-specific DOC bioavailability, linked with a Bayesian process model, to estimate means and posterior probability distributions for source-specific DOC decay rates in multisource bioassays. Modeled priming effects ranged from a -130 to +370% change in more stable DOC decay when incubated with unstable DOC. Glucose increased modeled river DOC decay by an average of 87% among all rivers. Glucose and algal leachates increased soil leachate and commercial humate decay by an average of 25% above background rates. Inorganic nutrient additions did not have consistent effects on DOC decay, likely because most of the study rivers had high ambient background nutrients. Our results demonstrate that the priming effect can augment DOC decay in rivers. In addition, Bayesian models can be used to estimate mechanisms driving aquatic ecosystem processes that are difficult to measure directly.

  • 317. Huayu, Lu
    et al.
    Stevens, Thomas
    Centre for the Environment, University of Oxford, UK .
    Shuangwen, Yi
    Xuefeng, Sun
    An erosional hiatus in Chinese loess sequences revealed by closely spaced optical dating2006In: Chinese Science Bulletin, ISSN 1001-6538, E-ISSN 1861-9541, Vol. 51, no 18, p. 2253-2259Article in journal (Refereed)
  • 318.
    Hugelius, Gustaf
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Kuhry, Peter
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Virtanen, Tarmo
    University of Helsinki.
    Kaverin, Dmitry
    Komi Science Centre.
    Pastukhov, Alexander
    Komi Science Centre.
    Rivkin, Felix
    Institute FSUE Fundamentprojekt.
    Marchenko, Sergey
    University of Alaska Fairbanks.
    Romanovsky, Vladimir
    University of Alaska Fairbanks.
    High‐resolution mapping of ecosystem carbon storageand potential effects of permafrost thaw in periglacialterrain, European Russian Arctic2011In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 116Article in journal (Refereed)
    Abstract [en]

    This study describes detailed partitioning of phytomass carbon (C) and soil organiccarbon (SOC) for four study areas in discontinuous permafrost terrain, Northeast EuropeanRussia. The mean aboveground phytomass C storage is 0.7 kg C m−2. Estimated landscapeSOC storage in the four areas varies between 34.5 and 47.0 kg C m−2 with LCC (landcover classification) upscaling and 32.5–49.0 kg C m−2 with soil map upscaling. A nestedupscaling approach using a Landsat thematic mapper land cover classification for thesurrounding region provides estimates within 5 ± 5% of the local high‐resolutionestimates. Permafrost peat plateaus hold the majority of total and frozen SOC, especially inthe more southern study areas. Burying of SOC through cryoturbation of O‐ or A‐horizonscontributes between 1% and 16% (mean 5%) of total landscape SOC. The effect ofactive layer deepening and thermokarst expansion on SOC remobilization is modeled forone of the four areas. The active layer thickness dynamics from 1980 to 2099 is modeledusing a transient spatially distributed permafrost model and lateral expansion of peatplateau thermokarst lakes is simulated using geographic information system analyses.Active layer deepening is expected to increase the proportion of SOC affected by seasonalthawing from 29% to 58%. A lateral expansion of 30 m would increase the amount ofSOC stored in thermokarst lakes/fens from 2% to 22% of all SOC. By the end of thiscentury, active layer deepening will likely affect more SOC than thermokarst expansion,but the SOC stores vulnerable to thermokarst are less decomposed.

  • 319. Hunt, Allen G.
    et al.
    Stefano, Manzoni
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Networks on Networks: The physics of geobiology and geochemistry2015Book (Other academic)
    Abstract [en]

    This book presents research into the physical rules that can underlie the behaviour of biota, as well as the geochemistry of soil development. It addresses both nutrient and water transport limitations of processes from chemical weathering to vascular plant growth. It attempts to bring order to the question of the extent to which soils can facilitate plant growth, and what limitations on plant sizes, metabolism, occurrence and correlations can be formulated thereby.

  • 320. Hwang, K. -J
    et al.
    Sibeck, D. G.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Choi, E.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.;Univ Space Res Assoc, Ctr Res & Explorat Space Sci & Technol, Greenbelt, MD USA..
    Chen, L. -J
    Ergun, R. E.
    Univ Colorado Boulder, Lab Atmospher & Space Phys, Boulder, CO USA..
    Khotyaintsev, Yuri
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Giles, B. L.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Pollock, C. J.
    Denali Sci LLC, Healy, AK USA..
    Gershman, D.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Dorelli, J. C.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Avanov, L.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Paterson, W. R.
    NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Burch, J. L.
    Southwest Res Inst, San Antonio, TX USA..
    Russell, C. T.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA USA..
    Strangeway, R. J.
    Torbert, R. B.
    Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA..
    Magnetospheric Multiscale mission observations of the outer electron diffusion region2017In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 44, no 5, p. 2049-2059Article in journal (Refereed)
    Abstract [en]

    This paper presents Magnetospheric Multiscale mission (MMS) observations of the exhaust region in the vicinity of the central reconnection site in Earth's magnetopause current sheet. High-time-resolution measurements of field and particle distributions enable us to explore the fine structure of the diffusion region near the X line. Ions are decoupled from the magnetic field throughout the entire current sheet crossing. Electron jets flow downstream from the X line at speeds greater than the ExB drift velocity. At/around the magnetospheric separatrix, large-amplitude electric fields containing field-aligned components accelerate electrons along the magnetic field toward the X line. Near the neutral sheet, crescent-shaped electron distributions appear coincident with (1) an out-of-plane electric field whose polarity is opposite to that of the reconnection electric field and (2) the energy transfer from bulk kinetic to field energy. The observations indicate that MMS passed through the edge of an elongated electron diffusion region (EDR) or the outer EDR in the exhaust region.

  • 321.
    Hylander, Lars D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Lindvall, Anders
    Foundation for Metal Biology, Öfre Slottsgatan 16A, S-753 12 Uppsala, Sweden.
    Gahnberg, Lars
    Public Dental Health Service, County of Uppsala, Ulleråkersvägen 21, S-750 17 Uppsala, Sweden.
    High mercury emissions from dental clinics despite amalgam separators2006In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 362, no 1-3, p. 74-84Article in journal (Refereed)
    Abstract [en]

    Mercury (Hg) as amalgam has been used as a dental filling material for more than 150 years. Thereby, dentists and their patients have been directly exposed to Hg, and the public and the environment indirectly exposed via Hg emissions from incinerators and Hg in waste water from households and dental clinics. Due to the toxic properties of Hg and bioaccumulation in biota of Hg emitted via dental clinic waste water, amalgam separators were introduced in Sweden in the 1980s. Although these amalgam separators in the certification process are required to remove at least 95% of incoming Hg in a standardized laboratory test, their efficiency in practical use has not been properly investigated. Here we present actual Hg emissions via waste water from 12 dental clinics equipped with the same type of amalgam separator based on sedimentation. All waste water was collected for four consecutive working days, initially at ordinary operating conditions and a second time after a thorough revision and cleaning of the discharge system. The results indicate that mercury emissions from dental clinics can be reduced by an improved design of the discharge system, a sensible use of high pressure water cleaning, and regular maintenance, including replacement of amalgam separators and filters at certain intervals. The study also indicates that banning Hg in dentistry is the one long-term way to stop Hg emissions from dental amalgam.

  • 322.
    Håkanson, Lars
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Andersson, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Uppsala Centre for Sustainable Development, CSD Uppsala, The Baltic University Programme.
    Rydén, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Uppsala Centre for Sustainable Development, CSD Uppsala, The Baltic University Programme.
    4. The Baltic Sea Basin: Nature, History, and Economy2003In: Environmental Science: Understanding, protecting and managing the environment in the Baltic Sea Region / [ed] Lars Rydén, Pawel Migula and Magnus Andersson, Uppsala: Baltic University Press , 2003, 1, p. 92-119Chapter in book (Other (popular science, discussion, etc.))
  • 323. Höglund, Lars Olof
    et al.
    Herbert Jr., Roger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Air and Water Science. Luft- och vattenlära.
    MiMi – Performance Assessment main report: Report from the MISTRA research program Mitigation of the environmental impact from mining waste (MiMi)2004Book (Other scientific)
  • 324.
    Höök, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Global Energy Systems.
    Depletion rate analysis of fields and regions: a methodological foundation2014In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 121, no 4, p. 95-108Article in journal (Refereed)
    Abstract [en]

    This paper presents a comprehensive mathematical framework for depletion rate analysis and ties it to the physics of depletion. Theory was compared with empirical data from 1036 fields and a number of regions. Strong agreement between theory and practice was found, indicating that the framework is plausible. Both single fields and entire regions exhibit similar depletion rate patterns, showing the generality of the approach. The maximum depletion rates for fields were found to be well described by a Weibull distribution.

    Depletion rates were also found to strongly correlate with decline rates. In particular, the depletion rate at peak was shown to be useful for predicting the future decline rate. Studies of regions indicate that a depletion rate of remaining recoverable resources in the range of 2–3% is consistent with historical experience. This agrees well with earlier “peak oil” forecasts and indicates that they rest on a solid scientific ground. 

  • 325.
    Höök, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Future coal production outlooks in the IPCC Emission Scenarios: Are they plausible?2011In: Energy and Environment, ISSN 0958-305X, E-ISSN 2048-4070, Vol. 22, no 7, p. 837-858Article in journal (Refereed)
    Abstract [en]

    Anthropogenic climate change caused by CO2 emissions is strongly linked to the future energy production, specifically coal. The Special Report on Emission Scenarios (SRES) contains 40 scenarios for future fossil fuel production and is used by the IPCC to assess future climate change. This study examines the SRES coal production outlooks. Fundamental assumptions regarding coal availability and production in SRES was also compared with recent studies on reasonable future production outlooks. It was found that SRES puts unreasonable expectation on just a few countries. Is it reasonable to expect that China, already accounting for 46% of the global output, would increase their production by a factor of 8 over the next 90 years, as implied by certain SRES scenarios? It is concluded that SRES is underpinned by a paradigm of perpetual growth and technological optimism as well as old and outdated resource estimates. This has resulted in overoptimistic production outlooks.

  • 326.
    Höök, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Mapping Chinese Supply2018In: Nature Energy, ISSN 0028-212X, E-ISSN 2213-0217, Vol. 3, no 3, p. 166-167Article in journal (Other academic)
    Abstract [en]

    Documenting the emissions and net energy of a crude supply could be essential to meeting national emission and energy security targets. Using data from hundreds of fields worldwide, a well-to-refinery study presents a high-granularity profile of China’s crude oil supply in terms of emissions and energy return on input.

  • 327.
    Höök, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Global Energy Systems.
    Dean, Fantazzini
    Moscow State University.
    André, Angelantoni
    Post Peak Living.
    Simon, Snowden
    University of Liverpool.
    Coal-to-Liquids: viability as a peak oil mitigation strategy2012In: Twenty Ninth Annual International Pittsburgh Coal Conference, 2012Conference paper (Refereed)
    Abstract [en]

    Converting coal to a liquid, commonly known as coal-to-liquids (CTL), can supply liquid fuels and has been successfully used in several countries, particularly in South Africa. However, it has not become a major contributor to the global oil supply. Increasing awareness of the scarcity of oil and rising oil prices has increased the interest in coal liquefaction. This paper surveys CTL technology, economics and environmental performance. Understanding the fundamental aspects of coal liquefaction technologies is vital for planning and policy-making since future CTL production will be integrated in a much larger global energy and liquid fuel production system.

    The economic analysis shows that many CTL studies assume conditions that are optimistic at best. In addition, the strong risk for a CTL plant to become a financial black hole is highlighted. This helps to explain why China has recently slowed down the development of its CTL program.

    The technical analysis investigates the coal consumption of CTL. Generally, a yield of between 1–2 barrels/ton coal can be achieved while the technical limit seems to be 3 barrels/ton coal. This puts a strict limit on future CTL capacity imposed by future coal production, regardless of other factors such as economic viability, emissions or environmental concern. For example, assuming that 10% of world coal production can be diverted to CTL, the contribution to the liquid fuel supply will be limited to only a few million barrels per day (Mb/d). This prevents CTL from becoming a viable mitigation plan for liquid fuel shortage on a global scale.

    However, it is still possible for individual nations to derive a significant share of their fuel supply from CTL but those nations must also have access to equally significant coal production capacity. It is unrealistic to claim that CTL provides a feasible solution to liquid fuels shortages created by peak oil. At best, it can be only a minor contributor and must be combined with other strategies to ensure future liquid fuel supply.

  • 328.
    Höök, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Global Energy Systems. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Li, Junchen
    China University of Petroleum - Beijing.
    Johansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Global Energy Systems.
    Snowden, Simon
    University of Liverpool.
    Growth rates of global energy systems and future outlooks2012In: Natural Resources Research, ISSN 1520-7439, E-ISSN 1573-8981, Vol. 21, no 1, p. 23-41Article in journal (Refereed)
    Abstract [en]

    The world is interconnected and powered by a number of global energy systems using fossil, nuclear, or renewable energy. This study reviews historical time series of energy production and growth for various energy sources. It compiles a theoretical and empirical foundation for understanding the behaviour underlying global energy systems' growth. The most extreme growth rates are found in fossil fuels. The presence of scaling behaviour, i.e. proportionality between growth rate and size, is established. The findings are used to investigate the consistency of several long-range scenarios expecting rapid growth for future energy systems. The validity of such projections is questioned, based on past experience. Finally, it is found that even if new energy systems undergo a rapid "oil boom"-development - i.e. they mimic the most extreme historical events - their contribution to global energy supply by 2050 will be marginal.

  • 329.
    Isaksson, Sven
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeological Research Laboratory.
    Hallgren, Fredrik
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeology.
    Lipid residue analyses of Early Neolithic funnel-beaker pottery from Skogsmossen, eastern Central Sweden, and the earliest evidence of dairying in Sweden2012In: Journal of Archaeological Science, ISSN 0305-4403, E-ISSN 1095-9238, Vol. 39, no 12, p. 3600-3609Article in journal (Refereed)
    Abstract [en]

    This study address the question of the use and function of Early Neolithic (4000-3000 cal. BC) funnel-beaker pots from Malardalen in eastern Central Sweden. The material studied is pottery from a wetland offering at the site Skogsmossen in the province of Vastmanland. While deposited under ritual circumstances in a fen, the pots were likely used in a domestic domain on the settlement adjacent to the offering fen, prior to final deposition. The lipid analysis indicate a varied vessel use, there are traces of aquatic resources, plants, terrestrial animals and milk. The identification of milk residue is the oldest so far from Sweden.

  • 330. Ivarsson, M.
    et al.
    Bengtson, S.
    Skogby, H.
    Lazor, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Belivanova, V.
    Marone, F.
    Extensive bioweathering of secondary minerals in subseafloor basalts2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203Article in journal (Other academic)
  • 331.
    Ivarsson, Magnus
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Broman, Curt
    Sturkell, Erik
    Ormö, Jens
    Siljeström, Sandra
    van Zuilen, Mark
    Bengtson, Stefan
    Swedish Museum of Natural History, Department of Paleobiology.
    Fungal colonization of an Ordovician impact-induced hydrothermal system.2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, no 3487, p. 1-6Article in journal (Refereed)
  • 332.
    Jacks, Gunnar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Von Brömssen, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Slejkokovec, Z.
    Nilsson, E.
    Arsenic and its bioavailability in surface waters in a black schist area in northern Sweden2012In: Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment, Taylor & Francis Group, 2012, p. 249-250Conference paper (Refereed)
    Abstract [en]

    The Västerbotten county in northern Sweden is largely underlain by Precambrian bedrock. There are numerous sulfide ore bodies and gold deposits accompanied by arsenic. However, more black schists with a sulfur content of about 1% are a more widespread source of arsenic (As). The arsenic is accumulated in the B-horizon of tills but also remobilized in wetlands and released into surface water. Sandy sediments in brooks and streams may contain up to 500 mg/kg As adsorbed onto ferric (Fe) oxyhydroxides. Lakes may contain up to 19 ÎŒg/LAs. Speciation of As has been investigated in lake water by filtration and dialysis. Four lakes have been investigated varying from a clear-water lake to lakes high in Fe and DOC (dissolved organic carbon). The As is closely correlated to Fe in the different fractions. The fraction < 1 kDa is low in As indicating that the As has low bioavailability. Fishing is important in the area both for local people as well as for tourists. The low bioavailability of As is verified by a few analysis of fish, pike and trout, in which the As content is relatively low and consisting of predominantly organic species like MMA, DMA and arsenobetaine. Thus in spite of elevated As contents in sediments and in water the As does not seem to pose a health risk for fish consumers.

  • 333.
    Jagt, John
    et al.
    Natuurhistorisch Museum Maastricht.
    Thuy, Ben
    Geoscience Centre, University of Göttingen.
    Donovan, Stephen K.
    Naturalis Biodiversity Centre, Leiden.
    Stöhr, Sabine
    Swedish Museum of Natural History, Department of Zoology.
    Portell, Roger W.
    Pickerill, Ron K.
    Harper, David A. T.
    Lindsay, William
    Jackson, Trevor A.
    A starfish bed in the Middle Miocene Grand Bay Formation of Carriacou, The Grenadines (West Indies)2014In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 151, no 3, p. 381-393Article in journal (Refereed)
  • 334.
    Jakobsson, Kristofer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Bentley, Roger
    University of Reading.
    Söderbergh, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Aleklett, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    The end of cheap oil: Bottom-up economic and geologic modeling of aggregate oil production curves2012In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 41, p. 860-870Article in journal (Refereed)
    Abstract [en]

    There is a lively debate between 'concerned' and 'unconcerned' analysts regarding the future availability and affordability of oil. We critically examine two interrelated and seemingly plausible arguments for an unconcerned view: (1) there is a growing amount of remaining reserves: (2) there is a large amount of oil with a relatively low average production cost. These statements are unconvincing on both theoretical and empirical grounds. Oil availability is about flows rather than stocks, and average cost is not relevant in the determination of price and output. We subsequently implement a bottom-up model of regional oil production with micro-foundations in both natural science and economics. An oil producer optimizes net present value under the constraints of reservoir dynamics, technological capacity and economic circumstances. Optimal production profiles for different reservoir drives and economic scenarios are derived. The field model is then combined with a discovery model of random sampling from a lognormal field size-frequency distribution. Regional discovery and production scenarios are generated. Our approach does not rely on the simple assumptions of top-down models such as the Hubbert curve - however it leads to the same qualitative result that production peaks when a substantial fraction of the recoverable resource remains in-ground.

  • 335.
    Jakobsson, Kristofer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Söderbergh, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Snowden, Simon
    University of Liverpool Management School.
    Aleklett, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Bottom-up modeling of oil production: Review and sensitivity analysisManuscript (preprint) (Other academic)
  • 336.
    Jakobsson, Kristofer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Söderbergh, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Snowden, Simon
    University of Liverpool Management School.
    Li, Chuan-Zhong
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Economics.
    Aleklett, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Global Energy Systems.
    Oil exploration and perceptions of scarcity: The fallacy of early success2012In: Energy Economics, ISSN 0140-9883, E-ISSN 1873-6181, Vol. 34, no 4, p. 1226-1233Article in journal (Refereed)
    Abstract [en]

    It has been suggested that oil exploration may lead to false perceptions of decreasing scarcity. We perform a simulation of the exploration process using Bayesian updating. The approach enables us to isolate the information effect on the success rate and also to quantify the subjective expectation of the total resource size. The area under exploration consists of a number of regions which may differ in their oil content. Exploration is performed with the goal to maximize the expected success rate. The resulting information about the distribution of oil and the total resource size is assumed public knowledge. A number of scenarios with variations in the dimensions of the area under exploration, the oil distribution and initial beliefs are considered. The results indicate that the information effect on the success rate is significant but brief — it might have a considerable impact on price but is an unlikely mechanism behind a long-term declining price trend. However, the information effect on expectations is gradual and persistent. Since exploration is performed in regions where the expected success rate is the highest, the historical success rate will not be representative of the area as a whole. An explorer will tend to overestimate the total resource size, thereby suggesting an alternative mechanism for false perceptions of decreasing scarcity, a mechanism that could be called the “fallacy of early success”.

  • 337.
    Jakobsson, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Marin geovetenskap.
    Backman, Jan
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Marin geovetenskap.
    Rudels, Bert
    Nycander, Jonas
    Department of Meteorology. Oceanografi.
    Frank, Martin
    Mayer, Larry
    Jokat, Wilfried
    Sangiorgi, Fransesca
    O'Regan, Matt
    Brinkhuis, Henk
    King, John
    Moran, Kathryn
    The Early Miocene Onset of a Ventilated Circulation Regime in the Arctic Ocean2007In: Nature, Vol. 447, no 7147, p. 986-990Article in journal (Refereed)
    Abstract [en]

    Deep-water formation in the northern North Atlantic Ocean and the Arctic Ocean is a key driver of the global thermohaline circulation and hence also of global climate. Deciphering the history of the circulation regime in the Arctic Ocean has long been prevented by the lack of data from cores of Cenozoic sediments from the Arctic’s deep-sea floor. Similarly, the timing of the opening of a connection between the northern North Atlantic and the Arctic Ocean, permitting deep-water exchange, has been poorly constrained. This situation changed when the first drill cores were recovered from the central Arctic Ocean. Here we use these cores to show that the transition from poorly oxygenated to fully oxygenated (‘ventilated’) conditions in the Arctic Ocean occurred during the later part of early Miocene times. We attribute this pronounced change in ventilation regime to the opening of the Fram Strait. A palaeo-geographic and palaeo-bathymetric reconstruction of the Arctic Ocean, together with a physical oceanographic analysis of the evolving strait and sill conditions in the Fram Strait, suggests that the Arctic Ocean went from an oxygenpoor ‘lake stage’, to a transitional ‘estuarine sea’ phase with variable ventilation, and finally to the fully ventilated ‘ocean’ phase 17.5 Myr ago. The timing of this palaeo-oceanographic change coincides with the onset of the middle Miocene climatic optimum, although it remains unclear if there is a causal relationship between these two events.

  • 338.
    Janssen, Ralf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    A molecular view of onychophoran segmentation2017In: Arthropod structure & development, ISSN 1467-8039, E-ISSN 1873-5495, Vol. 46, no 3, p. 341-353Article in journal (Refereed)
    Abstract [en]

    This paper summarizes our current knowledge on the expression and assumed function of Drosophila and (other) arthropod segmentation gene orthologs in Onychophora, a closely related outgroup to Arthropoda. This includes orthologs of the so-called Drosophila segmentation gene cascade including the Hox genes, as well as other genetic factors and pathways involved in non-drosophilid arthropods. Open questions about and around the topic are addressed, such as the definition of segments in onychophorans, the unclear regulation of conserved expression patterns downstream of non-conserved factors, and the potential role of mesodermal patterning in onychophoran segmentation. (C) 2016 Elsevier Ltd. All rights reserved.

  • 339.
    Japsen, Peter
    et al.
    Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark .
    Green, Paul F.
    Geotrack International, 37 Melville Road, Brunswick West, Victoria 3055, Australia .
    Bonow, Johan M.
    Mid Sweden University, Faculty of Human Sciences, Department of Tourism Studies and Geography. Södertörn University, Alfred Nobels allé 7, SE-141 89 Huddinge, Sweden.
    Erlström, Mikael
    Geological Survey of Sweden (SGU), Kiliansgatan 10, 223 50 Lund, Sweden .
    Episodic burial and exhumation of the southern Baltic Shield: Epeirogenic uplifts during and after break-up of Pangaea2016In: Gondwana Research, ISSN 1342-937X, E-ISSN 1878-0571, Vol. 35, p. 357-377Article in journal (Refereed)
    Abstract [en]

    Abstract Cratons are conventionally assumed to be areas of long-term stability. However, whereas Precambrian basement crops out across most of the Baltic Shield, Palaeozoic and Mesozoic sediments rest on basement in southern Sweden, and thus testify to a complex history of exhumation and burial. Our synthesis of published stratigraphic landscape analysis and new apatite fission-track analysis data reveals a history involving five steps after formation of the extremely flat, Sub-Cambrian Peneplain. (1) Cambrian to Lower Triassic rocks accumulated on the peneplain, interrupted by late Carboniferous uplift and exhumation. (2) Middle Triassic uplift removed the Palaeozoic cover along the south-western margin of the shield, leading to formation of a Triassic peneplain with a predominantly flat relief followed by deposition of Upper Triassic to Lower Jurassic rocks. (3) Uplift that began during the Middle Jurassic to earliest Cretaceous caused denudation leading to deep weathering that shaped an undulating, hilly relief that was buried below Upper Cretaceous to Oligocene sediments. (4) Early Miocene uplift and erosion produced the South Småland Peneplain with scattered hills. (5) Early Pliocene uplift raised the Miocene peneplain to its present elevation leading to reexposure of the sub-Cretaceous hilly relief near the coast. Our results thus provide constraints on the magnitude and timing of episodes of deposition and removal of significant volumes of Phanerozoic rocks across the southern portion of the Baltic Shield. Late Carboniferous, Middle Triassic and mid-Jurassic events of uplift and exhumation affected wide areas beyond the Baltic Shield, and we interpret them as epeirogenic uplifts accompanying fragmentation of Pangaea, caused by accumulation of mantle heat beneath the supercontinent. Early Miocene uplift affected north-west Europe but not East Greenland, and thus likely resulted from compressive stresses from an orogeny on the Eurasian plate. Early Pliocene uplift related to changes in mantle convection and plate motion affected wide areas beyond North-East Atlantic margins.

  • 340.
    Japsen, Peter
    et al.
    Geol Survey Denmark & Greenland GEUS, Oster Voldgade 10, DK-1350 Copenhagen, Denmark.
    Green, Paul F.
    Geotrack Int, 37 Melville Rd, Brunswick West, Vic 3055, Australia.
    Chalmers, James A.
    Geol Survey Denmark & Greenland GEUS, Oster Voldgade 10, DK-1350 Copenhagen, Denmark.
    Bonow, Johan M.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Social and Economic Geography. Geovisiona AB, Hogbyvagen 168, SE-17554 Jarfalla, Sweden.
    Mountains of southernmost Norway: uplifted Miocene peneplains and re-exposed Mesozoic surfaces2018In: Journal of the Geological Society, ISSN 0016-7649, E-ISSN 2041-479X, Vol. 175, no 5, p. 721-741Article in journal (Refereed)
    Abstract [en]

    The origin of the Norwegian mountains (the Scandes) is a key controversy in modern geoscience. Are they remnants from the Caledonian Orogeny, modified shoulders of late Mesozoic rifts, or are they evidence of Neogene uplifts? Our synthesis of geological data, landscape analysis and new thermochronological data from Norway south of c. 60 degrees N, combined with previously published data from southern Sweden, reveals a four-stage history: (1) Middle Triassic and Middle Jurassic exhumation produced a weathered basement surface with a hilly relief; (2) after late Mesozoic rifting, Upper Jurassic-Oligocene sediments accumulated across most of the area; (3) early Miocene uplift and erosion to the base level of the adjacent ocean led to formation of a peneplain that extended across sedimentary basins and Caledonian rocks; the subhorizontal Hardangervidda plateau represents this peneplain; (4) early Pliocene uplift raised Hardangervidda to its present elevation of c. 1200 m above sea-level and led to re-exposure of the tilted, Mesozoic surface at lower elevations. The Southern Scandes are thus, like other elevated passive continental margins around the world, the product of post-breakup uplift. Identification of the mechanisms driving these uplifts awaits geodynamic modelling constrained by observations such as those presented in this study.

  • 341.
    Jaramillo, Fernando
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Prieto, Carmen
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Multimethod assessment of evapotranspiration shifts due to non-irrigated agricultural development in Sweden2013In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 484, p. 55-62Article in journal (Refereed)
    Abstract [en]

    During the 20th century, Sweden underwent a persistent agricultural development. In this study, we use and combine historical hydroclimatic and agricultural data to investigate how this large scale change of land use, and subsequent intensification of crop production, affected regional hydrology in two adjacent Swedish drainage basins. We find a main increase of evapotranspiration (ET) as cultivated area and/or crop production increased during the period 1901-1940. Thereafter, ET stabilized at a new higher level. Comparison between the data given, water balance constrained ET quantification (ETwb), and a range of different comparative estimates of purely climate driven ET (ETclim) shows that only 31% of the steep 1901-1940 increase of ETwb can be explained by climate change alone. The remaining 69% of this ETwb shift, which occurred in both investigated drainage basins, is instead explainable to large degree by the regional land use conversion from seminatural grasslands to cultivated land and associated enhanced productivity of herbaceous species.

  • 342. Jarochowska, Emilia
    et al.
    Bremer, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Heidlas, Daniel
    Pröpster, Stephanie
    Vandenbroucke, Thijs
    Munnecke, Axel
    Multielement skeletal taphonomy in conodonts: are robust species more common or selectively preserved in shallow-water facies?2016Conference paper (Other academic)
  • 343. Jarochowska, Emilia
    et al.
    Viira, Viive
    Einasto, Rein
    Nawrot, Rafal
    Bremer, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Männik, Peep
    Munnecke, Axel
    Conodont Diversity Across The Onshore-Offshore Gradient: Cozy In Brine2016In: Geological Society of America Abstracts with Programs., 2016, Vol. 48Conference paper (Other academic)
  • 344. Jarrar, Ghaleb H.
    et al.
    Theye, Thomas
    Yaseen, Najel
    Whitehouse, Martin
    Pease, Victoria
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Passchier, Cees
    Geochemistry and P-T-t evolution of the Abu-Barqa Metamorphic Suite, SW Jordan, and implications for the tectonics of the northern Arabian-Nubian Shield2013In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 239, p. 56-78Article in journal (Refereed)
    Abstract [en]

    The Abu Barqa Metamorphic Suite (ABMS) represents the oldest part of the Arabian-Nubian Shield in southern Jordan. It comprises tonalitic gneiss, metasediments including schist and paragneiss, and granitic gneiss, intruded by later granitic bodies. Geochemically, the majority of the schist samples have shale and Fe-shale protoliths, while the paragneisses represent metagreywacke. Tectonic discrimination diagrams indicate that the protolith of the ABMS was deposited at an active continental margin/island arc setting. U-Pb zircon (SIMS) ages from metamorphic and igneous rocks of the ABMS indicate that it evolved between similar to 800 and similar to 610 Ma. A tonalitic gneiss has a crystallization age of 787 +/- 3 Ma. Detrital zircon from the metasediment has a range of concordant ages from 680 to 860 Ma. The entire metamorphic complex was intruded by calc-alkaline granitoids (similar to 615-610 Ma) and quartz diorite dated (similar to 600 Ma). Field and petrographic investigations of ABMS metasediment elucidate the development of three metamorphic zones, from north to south: (1) andalusite-staurolite (andalusite + staurolite + biotite + muscovite + plagioclase +/- garnet + quartz +/- chlorite + fibrolitic sillimanite + accessories), (2) garnetsillimanite (sillimanite + garnet + biotite + plagioclase + quartz + K-feldspar + cordierite (pinitized) +/- rutile +/- ilmenite), and (3) cordierite-sillimanite (sillimanite + biotite + plagioclase + cordierite + hercynite + quartz + accessories). The maximum metamorphic conditions (M1) were attained in the garnet-sillimanite zone (5-6 kbar, similar to 700 degrees C), while peak conditions of similar to 3.2 kbar and 540 degrees C were obtained for the andalusite-staurolite zone (using both forward-pseudosection modeling and inverse-modeling with multi-equilibrium approach). Compositional isopleth calculations of small relics of garnet yield about 3.5 kbar and 600 degrees C for the sillimanite-cordierite zone. These values are in agreement with results obtained by TWQ inverse modeling. The M1 event most probably occurred around similar to 625 and was followed by a decompressional thermal phase (M2) contemporaneous with post-tectonic granitoid emplacement at similar to 615-610 Ma; and lastly went through a retrograde cooling phase (M3) accompanying uplift of the whole complex to the surface at similar to 605 Ma.

  • 345.
    Jeddi, Zeinab
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Seismological Investigation of Katla Volcanic System (Iceland): 3D Velocity Structure and Overall Seismicity Pattern2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work in this thesis concentrates on Katla volcano in southern Iceland. This is one of Europe’s most active volcanoes and its history tells us that it poses many threats to society, both locally (Iceland) and on a broader scale (Europe). Its geological setting is complex, where the effects of a melting anomaly in the mantle and a changing rift geometry, perturb the classical setting of volcanism in a rifting setting.

    The work has focused on two aspects. The first is the varying distribution of physical properties in the subsurface around the volcano. The second is the distribution of microearthquakes around the volcano. The physical properties that we study are the speeds of seismic waves that reflect variations of temperature, composition and fracturing of the rocks. These can, therefore, help us learn about long-term processes in the volcano. The seismicity gives shorter-term information about deformation associated with current processes.

    I have applied two tomographic techniques to study Katla’s subsurface to a depth of 5-10 km, namely local-earthquake and ambient-noise tomography. The former makes use of the timing of waves generated by local earthquakes to constrain the earthquakes’ locations and the distribution of wave speed. Here I have concentrated on compressional waves or P waves with a typical frequency content around 10 Hz. With the latter, surface waves are extracted from microseismic noise that is generated far away at sea and their timing is measured to constrain their wave-speed distribution, which then is used to map shear-wave velocity variations. This is done at a typical frequency of 0.3 Hz. I find that the volcano contains rocks of higher velocity than its surroundings, that Katla’s caldera is underlain by low velocities at shallow depth that may be explained by hot or partially molten rocks and that beneath the caldera lies a volume of particularly high velocities that may constitute differentiated cumulates. But, I also find that it is not simple to compare results from such different wave types and discuss a number of complications in that regard.

    In addition to the well-known microearthquake distribution in the caldera region of Katla and to its west, we have discovered two additional areas of microearthquake activity on the volcano’s flanks, south and east of the caldera. These point to current activity and are, therefore, of interest from a hazard point of view. However, it is difficult to pinpoint their underlying process. Speculation about possible interpretation leads me to hydrothermal processes or small pockets of melt ascending due to their buoyancy or locally enhancing fluid pressure, thereby lowering the effective stress.

  • 346. Jennings, Anne
    et al.
    Andrews, John
    Pearce, Christof
    Aarhus University, Denmark.
    Wilson, Lindsay
    Ólfasdótttir, Sædís
    Detrital carbonate peaks on the Labrador shelf, a 13–7 ka template for freshwater forcing from the Hudson Strait outlet of the Laurentide Ice Sheet into the subpolar gyre2015In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 107, p. 62-80Article in journal (Refereed)
    Abstract [en]

    The Laurentide Ice Sheet (LIS) was a large, dynamic ice sheet in the early Holocene. The glacial events through Hudson Strait leading to its eventual demise are recorded in the well-dated Labrador shelf core, MD99-2236 from the Cartwright Saddle. We develop a detailed history of the timing of ice-sheet discharge events from the Hudson Strait outlet of the LIS during the Holocene using high-resolution detrital carbonate, ice rafted detritus (IRD), ή18O, and sediment color data. Eight detrital carbonate peaks (DCPs) associated with IRD peaks and light oxygen isotope events punctuate the MD99-2236 record between 11.5 and 8.0 ka. We use the stratigraphy of the DCPs developed from MD99-2236 to select the appropriate ΔR to calibrate the ages of recorded glacial events in Hudson Bay and Hudson Strait such that they match the DCPs in MD99-2236. We associate the eight DCPs with H0, Gold Cove advance, Noble Inlet advance, initial retreat of the Hudson Strait ice stream (HSIS) from Hudson Strait, opening of the Tyrrell Sea, and drainage of glacial lakes Agassiz and Ojibway. The opening of Foxe Channel and retreat of glacial ice from Foxe Basin are represented by a shoulder in the carbonate data. ΔR of 350 years applied to the radiocarbon ages constraining glacial events H0 through the opening of the Tyrell Sea provided the best match with the MD99-2236 DCPs; ΔR values and ages from the literature are used for the younger events. A very close age match was achieved between the 8.2 ka cold event in the Greenland ice cores, DCP7 (8.15 ka BP), and the drainage of glacial lakes Agassiz and Ojibway. Our stratigraphic comparison between the DCPs in MD99-2236 and the calibrated ages of Hudson Strait/Bay deglacial events shows that the retreat of the HSIS, the opening of the Tyrell Sea, and the catastrophic drainage of glacial lakes Agassiz and Ojibway at 8.2 ka are separate events that have been combined in previous estimates of the timing of the 8.2 ka event from marine records. SW Iceland shelf core MD99-2256 documents freshwater entrainment into the subpolar gyre from the Hudson Strait outlet via the Labrador, North Atlantic, and Irminger currents. The timing of freshwater release from the LIS Hudson Strait outlet in MD99-2236 matches evidence for freshwater forcing and LIS icebergs carrying foreign minerals to the SW Iceland shelf between 11.5 and 8.2 ka. The congruency of these records supports the conclusion of the entrainment of freshwater from the retreat of the LIS through Hudson Strait into the subpolar gyre and provides specific time periods when pulses of LIS freshwater were present to influence climate.

  • 347. Jeon, Heejin
    et al.
    Cho, Moonsup
    Kim, Hyeoncheol
    Horie, Kenji
    Hidaka, Hiroshi
    Early Archean to Middle Jurassic evolution of the Korean Peninsula and its correlation with Chinese cratons: SHRIMP U-Pb zircon age constraints2007In: The Journal of Geology, Vol. 115, no 5, p. 525-539Article in journal (Refereed)
  • 348. Jeon, Heejin
    et al.
    Cho, Moonsup
    Kim, Hyeoncheol
    Horie, Kenji
    Hidaka, Hiroshi
    U-Pb zircon geochronology of Early Jurassic Daedong Supergroup, South Korea: Tectonic implications2005In: AGU Fall Meeting Abstracts, 2005Conference paper (Refereed)
  • 349. Jeon, Heejin
    et al.
    Whitehouse, Martin J
    A critical evaluation of U–Pb calibration schemes used in SIMS zircon geochronology2015In: Geostandards and Geoanalytical Research, Vol. 39, no 4, p. 443-452Article in journal (Refereed)
  • 350. Jeon, Heejin
    et al.
    Williams, Ian
    Chappell, Bruce
    Oxygen isotopes of zircon rims and cores in the NEO (New England Orogen) S-type granites, eastern Australia2012In: 한국암석학회 학술발표회 녌묞집, p. 11-12Article in journal (Refereed)
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