Sökning: "peat accumulation"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden peat accumulation.

  1. 1. Incorporation and preservation of geochemical fingerprints in peat archives

    Detta är en avhandling från Umeå : Umeå Universitet

    Författare :Sophia V. Hansson; Umeå universitet.; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Peat; Beryllium; bulk density; C N-ratio; decomposition; deposition; downwash; elemental mobility; geochemistry; humification; lead; light transmission; mercury; peat accumulation; precipitation; Environmental Science; miljövetenskap;

    Sammanfattning : The present status of the environment, including environmental problems such as heavy metal accumulation in aquatic and terrestrial ecosystems, is in part the consequence of long-term changes. Cores from peatlands and other natural archives provide us with the potential to study aspects of the atmospheric cycling of elements, such as metal pollutants, on timescales much longer than the decade or two available to us with atmospheric deposition monitoring programs. LÄS MER

  2. 2. Holocene dynamics in subarctic peat plateaus of west-central Canada : Vegetation succession, peat accumulation and permafrost history

    Detta är en avhandling från Stockholm : Institutionen för naturgeografi och kvartärgeologi

    Författare :A. Britta K. Sannel; Stockholms universitet.; [2007]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; peatlands; permafrost; carbon accumulation; fire; subarctic; Holocene; NATURAL SCIENCES Earth sciences Exogenous earth sciences Physical geography; NATURVETENSKAP Geovetenskap Exogen geovetenskap Naturgeografi;

    Sammanfattning : Dynamics in vegetation, permafrost and peat and net carbon accumulation rates throughout the Holocene have been studied in two subarctic peat plateaus of west-central Canada through plant macrofossil analysis, geochemical analyses and AMS radiocarbon dating. Peatland formation at the studied sites began around 6600-5900 cal yr BP as a result of paludification of upland forests. LÄS MER

  3. 3. Temporal and spatial dynamics in subarctic peat plateaus and thermokarst lakes

    Detta är en avhandling från Stockholm : Department of Physical Geography and Quaternary Geology (INK), Stockholm University

    Författare :A. Britta K. Sannel; Stockholms universitet.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Peatlands; permafrost; subarctic; peat plateau; thermokarst lake; macrofossil analysis; carbon nitrogen ratio; peat accumulation; carbon accumulation; remote sensing; binary encoding; time-series analysis; Physical Geography; naturgeografi;

    Sammanfattning : Permafrost peatlands are widespread at high northern latitudes and are important soil organic carbon reservoirs. A future warming in these areas, as suggested by global climate models, can cause thawing and increased ground subsidence (thermokarst), resulting in changes in surface hydrology and ecosystem functioning. LÄS MER

  4. 4. Co-firing animal waste, sludge, residue wood, peat and forest fuels in a 50MWth CFB boiler ash transformation, availability and process improvements

    Detta är en avhandling från Umeå : Umeå universitet

    Författare :Henrik Hagman; Umeå universitet.; [2014]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Co-combustion; animal waste; peat; waste wood; forest residues; industrial sludge; limestone; CFB boiler; ash transformation; corrosion; erosion; ash and deposit characteristics; deposit buildup; boiler failures; availability; sulfation; boiler design; boiler conversion; waste derived fuels; large scale; Samförbränning; animaliskt avfall; torv; returträ; skogsbränsle; reningsslam; askomvandling; korrotion; erosion; ask- och beläggnings-karaktäristik; beläggningstillväxt; tillgänglighet; sulfatisering; panndesign; pannkonvertering; avfallsderiverade bränslen; storskalig;

    Sammanfattning : The direct variable costs for heat and electricity production based on solid biomass fuel combustion is approximately 3-5 times lower than the costs in a fossil fuel-oil based boiler in Sweden. In addition waste derived biomass fuels are typically much cheaper than biomass not classified as waste. LÄS MER

  5. 5. Subarctic ecosystem responses to climate, catchment and permafrost dynamics in the Holocene

    Detta är en avhandling från Department of Geology, Lund University

    Författare :Ulla Kokfelt; Lunds universitet.; Lund University.; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; subarctic Sweden; palsa mire development; peat; permafrost history; carbon and nutrient cycling; lake sediments;

    Sammanfattning : This thesis assesses aspects of the wetland development, permafrost dynamics and associated changes in carbon and nutrient cycling of the Stordalen Mire in northern Sweden. Various ecological and biogeochemical analyses of one peat and two lake sediment sequences were conducted, including analyses of organic matter and carbonate content, mosses, diatoms, testate amoebae, pigments, carbon and nitrogen and their stable isotopes, near infrared spectroscopy and biogenic silica. LÄS MER