Sökning: "subarctic"

Visar resultat 1 - 5 av 58 avhandlingar innehållade ordet subarctic.

  1. 1. Land-atmosphere interaction of a subarctic palsa mire

    Detta är en avhandling från GeoBiosphere Science Centre, Department of Physical Geography and Ecosystems Analysis, Lund University, Sölvegatan 12, 223 62, Lund, Sweden

    Författare :Marcin Jackowicz-Korczynski; Lunds universitet.; Lund University.; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; eddy covariance; chamber; methnaol; isoprene; nonmethane hydrocarbons; methane; carbon dioxide; carbon; mire; permafrost; subarctic; palsa; greenhouse gas;

    Sammanfattning : The main objective of this thesis was to quantitatively estimate the gaseous exchange of carbon dioxide (CO2) and methane (CH4) between a subarctic wetland ecosystem and the atmosphere. Additionally some initial estimates of the carbon input to the atmosphere of nonmethane hydrocarbons (NMHCs) were also obtained by combining different techniques in a joint setting. 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. Winter browsing by moose and hares in subarctic birch forest Scale dependency and responses to food addition

    Detta är en avhandling från Sundsvall : Mid Sweden University

    Författare :Sara Öhmark; Mittuniversitetet.; [2015]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Herbivory; subarctic; hare; moose; spatial scale;

    Sammanfattning : Despite their difference in body size and morphology, the moose (Alces alces) andthe mountain hare (Lepus timidus) sustain themselves during winter on similar plantspecies and plant parts in in subarctic environments, namely apical twigs ofmountain birch (Betula pubescens ssp. czerepanovii). LÄS MER

  4. 4. Temporal and spatial variability of carbon cycling in a subarctic landscape

    Detta är en avhandling från Department of Physical Geography and Ecosystem Science, Lund University

    Författare :Torbjörn Johansson; Lunds universitet.; Lund University.; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geologi; physical geography; Geology; Växtekologi; Plant ecology; Permafrost; Herbivory; Subarctic; Aerial photography; Vegetation change; Carbon balance; fysisk geografi;

    Sammanfattning : This thesis deals with the carbon balance in a subarctic landscape at different temporal and spatial scales. Its focus is mainly on the peatland and mountain birch forest (Betula pubescens ssp. czerepanovii) ecosystems within the Abisko area in northernmost Sweden. This is an area with a temperature close to the 0 OC mean annual isotherm. LÄS MER

  5. 5. Future stratospheric ozone depletion will affect a subarctic dwarf shrub ecosystem

    Detta är en avhandling från Biology building

    Författare :Ulf Johanson; Lunds universitet.; Lund University.; [1997]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Vaccinium; UVB; subarctic; shoot growth; ozone depletion; leaf thickness; irradiation system; heath ecosystem; Empetrum; dwarf shrubs; Calamagrostis; decomposition; Physiological biophysics; Växtfysiologi;

    Sammanfattning : Popular Abstract in Swedish Det stratosfäriska ozonlagret håller på att förtunnas och detta kommer att leda till att mer skadlig ultraviolett-B (UV-B) strålning når ner till biosfären. För att undersöka hur detta påverkar ett subarktiskt hedekosystem har vi bestrålat ett sådant med extra UV-B strålning motsvarande 15 % ozonförtunning. LÄS MER