The diets of laboratory rats were isotopically and nutritionally manipulated using purified C3 and/or C4 macronutrients to investigate the routing of dietary carbon to bone collagen biosynthesis. Diets were formulated with purified proteins, carbohydrates and lipids of defined composition and natural abundance stable isotope ratios. Bulk protein and constituent amino acid delta(13)C values dete...

We investigated population responses in physiology, morphology, and growth of mature Pinus ponderosa trees to an environmental gradient across Nebraska, USA. Ten populations from western Nebraska and eastern Wyoming were grown in three 26-year-old provenance tests from the warmest and wettest site in the east (Plattsmouth) to the intermediate site in the middle (Halsey) to the coldest and dries...

Scat is frequently used to study animal diets because it is easy to find and collect, but one concern is that gross fecal analysis (GFA) techniques exaggerate the importance of small-bodied prey to mammalian mesopredator diets. To capitalize on the benefits of scat, we suggest the analysis of scat carbon and nitrogen isotope values (δ13C and δ15N). This technique offers researchers a non-invasi...

C4 photosynthesis involves a close collaboration of the C3 and C4 metabolic cycles across the mesophyll and bundle-sheath cells. This study investigated the coordination of C4 photosynthesis in maize plants subjected to two salinity (50 and 100mM NaCl) treatments and one shade (20% of full sunlight) treatment. Photosynthetic efficiency was probed by combining leaf gas-exchange measurements with...

We analyzed carbon isotope ratios (delta13C) of liver and pectoral muscle of Black-throated Blue Warblers (Dendroica caerulescens) to provide a mesoscale perspective on altitudinal tenancy in the Appalachian Mountains, North Carolina, U.S.A. Movements of males are poorly understood, particularly the degree to which yearlings (first breeding season) and older males (second or later breeding seas...

We report isotopic data (delta(2)H, delta(18)O n = 196; delta(13)C, delta(15)N n = 142; delta(34)S n = 85) from human hair and drinking water (delta(2)H, delta(18)O n = 67) collected across China, India, Mongolia, and Pakistan. Hair isotope ratios reflected the large environmental isotopic gradients and dietary differences. Geographic information was recorded in H and O and to a lesser extent, ...

Alfalfa was labeled in the field with 99 atom % 13CO2 and cut either the same day (C1) or 30 d after labeling (C30). The C1 alfalfa contained 84% of the 13C label in cell contents, whereas C30 alfalfa contained 47% of the 13C label in cell contents. In two separate trials, C1 and C30 alfalfa were dosed to two or four Suffolk ewes fed natural abundance alfalfa diets. Carbon isotope ratios (13C/1...

land cover change constitutes one of main way of alteration of soil organic matter in both quantitative and qualitative terms. the goal of this study was to compare the carbon stock and the isotopic signature of the organic matter in the soil of areas with different land use, covered with forest and grass (pasture). the study area is located at sorocaba, sp, brazil. using un-deformed soil sampl...

Diet composition of carbon and nitrogen (C:N) could affect diet-tissue isotopic discrimination and elemental turnover rate in consumers but studies that test the nature of these changes are scarce. We compared carbon and nitrogen isotopic discrimination and turnover rates in individuals of Pallas' long-tongued bats Glossophaga soricina fed diets with protein soya isolate or amaranth grains as t...