Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate

Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate.

A broad compilation of modern carbon isotope compositions in all C3 plant types shows a monotonic increase in δ(13)C with decreasing mean annual precipitation (MAP) that differs from previous models. Corrections for temperature, altitude, or latitude are smaller than previously estimated. As corrected for altitude, latitude, and the δ(13)C of atmospheric CO(2), these data permit refined interpr...

Photosynthetic Mechanisms and Paleoecology from Carbon Isotope Ratios in Ancient Specimens of C4 and CAM Plants.

Carbon istotope ratios of modern, 10,000-year-old, and more than 40,000-year-old Atriplex confertifolia (C(4)) material from Nevada caves indicate that the C(4) photosynthetic pathway was operating in these plants over that period. Samples of a plant with crassulacean acid metabolism, Opuntia polyacantha, were also measured, and a shift in the 8(13)C value from -21.9 per mil (more than 40,000 y...

Continental Carbonates as Indicators of Paleoclimate

Clarifying the influence of water availability and plant types on carbon isotope discrimination by C3 plants.

We are pleased that the results of Kohn (1) so strongly support our findings published earlier in PNAS (2). Both studies (1, 2) analyzed published measurements of the carbon isotope composition of plants and quantified relationships between isotopic fractionation and environmental factors at large spatial scales. These relationships will be useful when interpreting archives of plant-derived car...

investigation of the electronic properties of carbon and iii-v nanotubes

boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...