7 RATIONALE: Bulk and position-specific stable isotope characterization of nitrous oxide 8 represents one of the most powerful tools for identifying its environmental sources and sinks.

After 2004 and 2008 (Vols. 378/2 and 390/2) this is the third issue of Analytical and Bioanalytical Chemistry to contain papers on new developments and applications in isotope ratio measurements. Whereas Klaus Heumann was guest editor for the two previous special issues, in this issue Torsten Schmidt joins him as guest editor for the first time. His involvement with this collection of papers st...

For examining vitamins, exact quantitations in natural matrices are essential. Up to date, one of the most accurate quantitation methods is the stable isotope dilution assay (SIDA), which is based on the use of isotopically labelled analogues of the analytes as internal standards. The merits of SIDA include the ideal compensation for losses, superior specificity and enhanced sensitivity due to ...

OBJECTIVES A previous multi-isotope study of archaeological faunal samples from Skútustaðir, an early Viking age settlement on the southern shores of Lake Mývatn in north-east Iceland, demonstrated that there are clear differences in δ(34)S stable isotope values between animals deriving their dietary protein from terrestrial, freshwater, and marine reservoirs. The aim of this study was to use t...

Sea-to-land nutrient transfers can connect marine food webs to those on land, creating a dependence on marine webs by opportunistic species. We show how nitrogen, imported by gray seals, Halichoerus grypus, and traced through stable isotope (δ15 N) measurements in marram grass, Ammophila breviligulata, significantly alters foraging behavior of a free-roaming megaherbivore (feral horses, Equus f...

The turkey (Meleagris gallopavo) represents one of the few domestic animals of the New World. While current research points to distinct domestication centres in the Southwest USA and Mesoamerica, several questions regarding the number of progenitor populations, and the timing and intensity of turkey husbandry remain unanswered. This study applied ancient mitochondrial DNA and stable isotope (δ1...

There have been numerous recent observations of changes in the behavior and dynamics of migratory bird populations, but the plasticity of the migratory trait and our inability to track small animals over large distances have hindered investigation of the mechanisms behind migratory change. We used habitat-specific stable isotope signatures to show that recently evolved allopatric wintering popu...

Preceramic human skeletal remains preserved in submerged caves near Tulum in the Mexican state of Quintana Roo, Mexico, reveal conflicting results regarding 14C dating. Here we use U-series techniques for dating a stalagmite overgrowing the pelvis of a human skeleton discovered in the submerged Chan Hol cave. The oldest closed system U/Th age comes from around 21 mm above the pelvis defining th...

Over the last few decades, the use of stable isotope ratios in ecological studies has increased greatly, most notably in the area of trophic ecology and food webs (Peterson and Fry 1987, Fry 2006). However, applications of stable isotopes in food web studies have been mostly qualitative to date, prompting the recent development of quantitative approaches to investigate different aspects of trop...

Ontogenetic niche shifts occur across diverse taxonomic groups, and can have critical implications for population dynamics, community structure, and ecosystem function. In this study, we provide a hypothesis-testing framework combining univariate and multivariate analyses to examine ontogenetic niche shifts using stable isotope ratios. This framework is based on three distinct ontogenetic niche...