Key-words: particulate organic matter, periphyton, nitrogen stable isotope, subtropical river The stable nitrogen isotope ratios (δ15N) of particulate organic matter (POM) and periphyton were measured at sites along the Dashahe River, a short subtropical watercourse in SE China. δ15N values of both POM and periphyton tended to increase from upstream to downstream, ranging from 1.1‰ to 7.4‰ for ...

This research investigates the potential of a new, noninvasive method for determining age of weaning among primates using stable carbon and nitrogen isotope ratios in feces. Analysis of stable isotope ratios in body tissues is a well-established method in archeology and ecology for reconstructing diet. This is the first study to investigate weaning in primates using fecal stable isotope ratios....

The Mesozoic is marked by several widespread occurrences of intense organic matter burial. Sediments from the largest of these events, the Cenomanian-Turonian Oceanic Anoxic Event (OAE 2) are characterized by lower nitrogen isotope ratios than are seen in modern marine settings. It has remained a challenge to describe a nitrogen cycle that could achieve such isotopic depletion. Here we use nitr...

Organisms that use ammonium as the sole nitrogen source discriminate between [(15)N] and [(14)N] ammonium. This selectivity leaves an isotopic signature in their biomass that depends on the external concentration of ammonium. To dissect how differences in discrimination arise molecularly, we examined a wild-type (WT) strain of Escherichia coli K12 and mutant strains with lesions affecting ammon...

Stable isotope analysis has been used as a technique to analyse fisheries food webs for a quarter of a century, and remains the principal method for determining energy and nutrient pathways from primary producers to consumers in aquatic ecosystems. Carbon isotope analysis has been used to distinguish autotrophs at the base of inshore and offshore fisheries food webs. The combination of nitrogen...

We examine the ecology of reddish-gray mouse lemurs from three habitats at Beza Mahafaly Special Reserve using focal follows and stable carbon and nitrogen isotope data. Focal observations indicate dietary differences among habitats as well as sexes and seasons. Both sexes consume more arthropods during the rainy season but overall, females consume more sugar-rich exudates and fruit than males,...

RATIONALE Stable isotope analysis is a critical tool for understanding ecological food webs; however, results can be sensitive to sample preparation methods. To limit the possibility of sample contamination, freezing is commonly used to euthanize invertebrates and preserve non-lethal samples from vertebrates. For destructive sampling of vertebrates, more humane euthanasia methods are preferred ...

We examine the relationship between mesowear variables and carbon and nitrogen isotopes in 16 species of African antelope (Mammalia: Bovidae). We show significant differences in carbon and nitrogen isotope values between individuals exhibiting sharp versus round cusps, and high versus low occlusal relief. We show significant correlations between mesowear variables and both carbon and nitrogen i...

This study examines stable isotope ratios of carbon and nitrogen in bone collagen and the elemental concentrations of strontium in the bone mineral of terrestrial vertebrates fi'om a variety of ecosystems. Documentation of the separation oftrophic levels by these indices is essential for the assessment of the trophic position of prehistoric humans. Particular emphasis is given to carnivores in ...

Norlin, E., 2005. Nitrogen Isotope Analysis of Ammonium and Glycine. Method Development for Aqueous Solutions and Soil Extracts. Doctor ́s dissertation. ISSN 1652-6880, ISBN 91-576-6983-X Stable isotope techniques can be used as a tool in nitrogen cycling studies of different ecosystems. The studies are based on measurement of the heavy (N)tolight (N) isotopic ratios of nitrogen in different bio...