Temperature Dependence of Isotope Ratios in Tree Rings

Temperature dependence of isotope ratios in tree rings.

The stable isotope ratios of carbon, oxygen, and hydrogen have been measured for a German oak in wood samples of roughly three years each, for the years 1712-1954 A.D., and correlated with the existing weather records from England, Basel, and Geneva to evaluate the empirical temperature coefficients. Isotope ratios in a second official oak, measured for the years 1530-1800 A.D., show the cold t...

On estimating the precision of stable isotope ratios in processed tree-rings

Temperature Dependence of Carbon Isotope Fractionation in CAM Plants.

The carbon isotope fractionation associated with nocturnal malic acid synthesis in Kalanchoë daigremontiana and Bryophyllum tubiflorum was calculated from the isotopic composition of carbon-4 of malic acid, after appropriate corrections. In the lowest temperature treatment (17 degrees C nights, 23 degrees C days), the isotope fractionation for both plants is -4 per thousand (that is, malate is ...

Viscosity and temperature dependence of the magnetic isotope effect

The 13C enrichment observed in the first order photolytic decomposition of dibenzylketone (1,3-diphenyl2-propanone) was studied as a function of solvent viscosity and temperature. The isotope effect is due to electron-nuclear hyperfine interactions in the free radical intermediates of the reaction. The results are explained using a continuum diffusion model and a simplified version of the radic...

Reconstructing the temperature degree of the warm seasons through Quercus persica tree rings in Zagros forests Dena region

Trees can record long-term effects of climate variables. Using dendroclimatology knowledge, we can reconstruct such variables especially for areas which have short-term climatic data. For this purpose, we reconstructed the temperature degree of the warm months (May-September) through annual rings width of Quercus persica and regression analysis of data obtained from stations on Dena region. Wit...