Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sul- fate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in ma- jor transformation pathways. (documents.pub)
In the troposphere, this isotope composition is determined by "physical" fractionation effects, that are phase changes (e.g. during cloud formation), diffusion processes (e.g. during evaporation from the ocean), and mixing of air masses. (123dok.net)
In contrast, in the stratosphere and mesosphere "chemical" fractionation mechanisms, that are the produc-tion of H2O due to the oxidation of methane, re-cycling of H2O via the HOxfamily, and isotope exchange reactions con-siderably enhance the isotope ratios in the water vapour im-ported from the troposphere. (123dok.net)
The major uncertainty in our calculation arises from poorly quantified isotope exchange reaction rate coefficients and kinetic isotope fractionation factors. (123dok.net)
Reaction1
The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. (documents.pub)
Investigate1
Stable isotopes have frequently been used to investigate plant carnivory since significant accumulation of a heavier or lighter isotope in plant tissue provides clear evidence of nutrient transfer from dead animals to plants. (elementar.com)
Atmosphere1
Throughout the middle atmosphere, MDF O2 is the major donator of oxy-gen atoms incorporated in OH and HO2 and thus in H2O. (123dok.net)
Analysis1
After 1 week and 2 weeks, the leaves were collected, ground to powder and sent to the University of British Columbia (UBC) Stable Isotope Facility for isotopic analysis. (elementar.com)
Study3
The results presented in this study will be par- ticularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxida- tion pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone. (documents.pub)
to study the stable hydrogen (D) and stable oxygen isotope (17O,18O) composition of water vapour in stratosphere and mesosphere. (123dok.net)
There are only 11 independent origins of plant carnivory recognized, in this study the discovery of a new lineage of carnivorous plants, represented by the Triantha occidentalis , a rhizomatous perennial herb found along the west coast of North America, is reported. (elementar.com)