Search for dissertations about: "Nils Holm"
Showing result 6 - 10 of 11 swedish dissertations containing the words Nils Holm.
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6. Abiotic and biotic methane dynamics in relation to the origin of life
Abstract : 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. READ MORE
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7. Ocean chemistry and the evolution of multicellularity
Abstract : Oxygen has been assumed to be a vital trigger for the evolution of multicellular life forms on Earth, partly based on its power to promote substantial energy flux in cell respiration and partly as biosynthesis of compounds like collagen require oxygen. However, the co-evolution of large life and the Earth’s chemical environment is not well understood at present, and there is particular disagreement in the field about whether the Cambrian explosion of animal life forms was a chemical or biological event. READ MORE
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8. Fossilized microorganisms in volcanic rocks from sub-seafloor environments
Abstract : Fossilized microorganisms are focused in this thesis. Such organisms have been observed in drilled basalt samples from the Emperor Seamounts in the Pacific Ocean collected during ODP (Ocean Drilling Program) Leg 197. READ MORE
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9. Origin of organic compounds in fluids from ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge
Abstract : Natural gas, primarily methane (CH4), is produced in substantial amounts in ultramafic-hosted hydrothermal systems. These systems could also generate oil (heavier hydrocarbons) and the first building blocks of life (prebiotic molecules). In the presence of iron bearing minerals, serpentinisation reactions generate H2. READ MORE
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10. Low temperature olivine alteration ; an experimental approach
Abstract : Water reacting with minerals to alter or dissolve them is a common phenomenon on Earth, leading to a unique chemical composition of the oceans and continents. The continuous circulation of elements and the chemical reactions between them creates the extraordinary environment prevailing on our Earth today and was probably an important requirement for the onset of life on our planet. READ MORE