Sökning: "δ13C"

Visar resultat 6 - 10 av 36 avhandlingar innehållade ordet δ13C.

1. 6. Achieving carbon isotope mass balance in northern forest soils, soil respiration and fungi

   Författare :Björn Boström; Alf Ekblad; Phil Ineson; Örebro universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 13C; Carbon cycle; Ectomycorrhizal fungi; Forest soil; Microbial respiration; Soil respiration; Stable isotopes; Biology; Biologi; Biology; Biologi;

   Sammanfattning : Northern forests contain a large part of the global terrestrial carbon pool and it is unclear whether they will be sinks or sources for atmospheric carbon if the climate warms as predicted. Stable isotope techniques provide unique tools to study the carbon cycle at different scales but the interpretation of the isotope data is impaired by our inability to close the carbon isotope mass balance of ecosystems. LÄS MER

3. 7. Late Holocene humidity variability in central Sweden

   Författare :Sofia Andersson; Stefan Wastegård; Gunhild Rosqvist; Kristian Schoning; Frank Chambers; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; humidity change; stable isotopes; Chara spp; Pisidium spp; testate amoebae assemblages; humification; C N ratio; late Holocene; central Sweden; Quaternary geology; Kvartärgeologi; kvartärgeologi; Quarternary Geology;

   Sammanfattning : The aim of this thesis was to reconstruct humidity variability in central Sweden during the late Holocene. A multi-proxy approach was used to infer humidity changes as recorded in a lake and a mire. Age-models were constructed based on radiocarbon dating and the Askja-1875 tephra. LÄS MER

4. 8. Explaining temporal variations in soil respiration rates and delta13C in coniferous forest ecosystems

   Författare :Daniel Comstedt; Alf Ekblad; Rolf Siegwolf; Örebro universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Autotrophic; Boreal forest; Elevated CO2; 13C; Natural abundance of stable isotopes; Picea abies; PLS; Root respiration; Soil respiration; Biology; Biologi; Biology; Biologi;

   Sammanfattning : Soils of Northern Hemisphere forests contain a large part of the global terrestrial carbon (C) pool. Even small changes in this pool can have large impact on atmospheric [CO2] and the global climate. LÄS MER

5. 9. Model analysis of ocean carbon storage and transport across climate states

   Författare :Malin Ödalen; Jonas Nycander; Johan Nilsson; Kevin I. C. Oliver; Nathaelle Bouttes-Mauhourat; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Oceanography; Climate; Climate model; Carbon cycle; Paleoclimate; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

   Sammanfattning : The ocean carbon cycle plays a fundamental role in the Earth’s climate system, on decadal to multi-millennial timescales. Of the carbon held in the ocean, the atmosphere, and the terrestrial biosphere combined, more than 90% resides in the ocean. Carbon enters the surface ocean through air-sea gas exchange and from terrestrial sources. LÄS MER

7. 10. Application of two dimensional compound specific carbon-chlorine isotope analyses for degradation monitoring and assessment of organic pollutants in contaminated soil and groundwater

   Författare :Charline Wiegert; Örjan Gustafsson; Thomas Hofstetter; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; organochlorines; chlorinated ethenes; PCE; TCE; hexachlorocyclohexanes; soil contamination; groundwater contamination; remediation; natural attenuation; biodegradation; carbon isotopes; chlorine isotopes; CSIA; Applied Environmental Science; tillämpad miljövetenskap;

   Sammanfattning : Nearly 250,000 sites with past and present potentially polluting activities need urgent remediation within Europe. Major pollutants include organochlorines (OCls), e.g. chlorinated ethenes (CEs) and hexachlorocyclohexanes (HCHs), mainly used as industrial solvents and pesticides, respectively. LÄS MER