Sökning: "methane CH4"

Visar resultat 1 - 5 av 98 avhandlingar innehållade orden methane CH4.

  1. 1. Abiotic and biotic methane dynamics in relation to the origin of life

    Författare :Nguyen Thanh Duc; David Bastviken; Patrick Crill; Nils Holm; Edward Hornibrook; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; methane; methanogens; methane formation; methane oxidation; lake sediment; olivine; origin of life; geokemi; Geochemistry;

    Sammanfattning : Methane (CH4) plays an important role in regulating Earth’s climate. Its atmospheric concentrations are related to both biotic and abiotic processes. The biotic one can be formed either by chemoautotrophic or heterotrophic pathways by methanogens. LÄS MER

  3. 2. Methane dynamics in northern lakes : Insights from multi-scale observations

    Författare :Jonathan Schenk; David Bastviken; Magnus Gålfalk; Damien Maher; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Methane; Lakes; Variability; Sampling design; Models;

    Sammanfattning : Methane (CH4) is a potent greenhouse gas which is emitted to the atmosphere from both natural and anthropogenic sources. Current evidence indicates that lakes account for a large part of the global emissions of CH4, but their contribution is difficult to quantify because of large temporal and spatial variability in processes leading to CH4 fluxes from lakes to the atmosphere. LÄS MER

  4. 3. Geophysical Applications of Vegetation Modeling

    Författare :Jed O Kaplan; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Environmental chemistry; Växtbiokemi; Plant biochemistry; CH4; CO2; stable isotopes; carbon cycle; wetland; ice core; methane; Holocene; mammoths; tundra; ice age; LGM; biogeography; biome; biogeochemistry; Vegetation model; Miljökemi; Physical geography; geomorphology; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

    Sammanfattning : This thesis describes the development and selected applications of a global vegetation model, BIOME4. The model is applied to problems in high-latitude vegetation distribution and climate, trace gas production, and isotope biogeochemistry. LÄS MER

  5. 4. Freshwater methane and carbon dioxide fluxes : Spatio-temporal variability and an integrated assessment of lake and stream emissions in a catchment

    Författare :Sivakiruthika Natchimuthu; David Bastviken; Åsa Danielsson; Peter A. Raymond; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Lakes; streams; spatio-temporal variability; CH4 flux; CO2 flux; gas transfer velocity; Sjöar; vattendrag; rumsliga och tidsmässiga variationer; CH4-flöden; CO2-flöden; gasutbyteshastighet;

    Sammanfattning : Freshwater bodies such as lakes and streams release the greenhouse gases methane (CH4) and carbon dioxide (CO2) into the atmosphere. Global freshwater CH4 and CO2 emissions have been estimated to be of a similar magnitude to the global land or ocean carbon sink, and are thus significant components of global carbon budgets. LÄS MER

  7. 5. Lake Fluxes of Methane and Carbon Dioxide

    Författare :Eva Podgrajsek; Erik Sahlée; Dennis Baldocchi; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; air-lake gas exchange; carbon dioxide; eddy covariance; floating chambers; methane; waterside convection; Meteorology; Meteorologi;

    Sammanfattning : Methane (CH4) and carbon dioxide (CO2) are two important greenhouse gases. Recent studies have shown that lakes, although they cover a small area of the globe, can be very important natural sources of atmospheric CH4 and CO2. LÄS MER