Search for dissertations about: "carbon isotopes"

Showing result 21 - 25 of 84 swedish dissertations containing the words carbon isotopes.

  2. 21. Emission of methane from northern lakes and ponds

    Author : Martin Wik; Patrick Crill; Isabelle Laurion; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; lakes; ponds; water bodies; methane; fluxes; ebullition; stable isotopes; arctic; subarctic; carbon cycling; climate change; geokemi; Geochemistry;

    Abstract : Northern lakes and ponds are abundant and emit large amounts of the potent climate forcer methane to the atmosphere at rates prone to change with amplified Arctic warming. In spite of being important, fluxes from surface waters are not well understood. READ MORE

  4. 22. A combined carbon and hydrogen isotope approach to reconstruct the SE Asian paleomonsoon : Impacts on the Angkor Civilization and links to paleolimnology

    Author : Kweku Kyei Afrifa Yamoah; Rienk Smittenberg; Sarah Feakins; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Holocene; summer monsoon; biomarkers; hydrogen isotopes; lake sediment; peat; Thailand; geokemi; Geochemistry;

    Abstract : Changes in monsoon patterns not only affect ecosystems and societies but also the global climate system in terms of heat energy and humidity transfer from the equator to higher latitudes. However, understanding the mechanisms that drive monsoon variability on longer timescales remains a challenge, partly due to sparse paleoenvironmental and paleoclimatic data. READ MORE

  5. 23. Holocene climate and environmental change in high latitudes as recorded by stable isotopes in peat deposits

    Author : Päivi Kaislahti Tillman; Steffen Holzkämper; Stefan Wastegård; Peter Kuhry; Thomas W. D. Edwards; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; stable isotopes; Holocene; subarctic; climate; Sphagnum fuscum; kvartärgeologi; Quarternary Geology;

    Abstract : In this thesis, stable carbon and oxygen isotopes in α-cellulose isolated from Sphagnum fuscum moss remains were used as climate proxies. The main focus was to implement the methods in records from high latitude peatlands in the Northern Hemisphere (west-central Canada and north-eastern European Russia), reconstruct palaeoclimate of the studied regions during the Holocene, and evaluate the compatibility of results with other proxy records, especially tree-ring isotope time-series. READ MORE

  6. 24. Studies of Long-lived Radionuclides in the Environment - with Emphasis on 99Tc, 237Np and Pu Isotopes

    Author : Patric Lindahl; Lund Medicinsk strålningsfysik; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Nuclear medicine; radiobiology; Nukleärmedicin; radiobiologi; atomic ratio; environmental samples; nuclear weapons fallout; Chernobyl fallout; bioindicators; activated carbon; Sellafield; plutonium; neptunium; ICP-MS; technetium;

    Abstract : Studies of the long-lived anthropogenic radionuclides 99Tc, 237Np, 239Pu and 240Pu were performed in marine and terrestrial areas contaminated by different accidental and controlled releases of radioactive materials. The three main sources discussed in this thesis are nuclear weapons tests, nuclear reprocessing plants and the Chernobyl accident. READ MORE

  7. 25. The global marine carbon system through time

    Author : Jenny Hieronymus; Jonas Nycander; Gösta Walin; Michael Follows; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

    Abstract : Carbon dioxide is an important greenhouse gas and in order to understand its effect on the climate we need to identify its sources and sinks. This thesis focuses on different aspects of the marine carbon system and the exchange of carbon between the ocean and the atmosphere. READ MORE