Natural stable isotope ratios (δ15N) of humans can be used for nutritional analyses and dietary reconstruction of modern and historic individuals and populations. Information about an individual's metabolic state can be obtained by comparison of tissue and dietary δ15N. Different methods have been used to estimate dietary δ15N in the past; however, the validity of such predictions has not been ...

Extremes in δ15N values in mangrove tissues and lichens (range =+4 to −22‰) were measured from a mangrove forest ecosystem located on Twin Cays, offshore islands in Belize, Central America. The N isotopic compositions and concentrations of NH+4 /NH3 in porewater, rainwater, and atmospheric ammonia, and the δ15N of lichens, mangrove leaves, roots, stems, and wood were examined to study the bioge...

Nitrogen and carbon stable isotopic compositions (δ15N and δ13C) of consumers have been used for physiological and food web studies. Previous studies have shown δ15N and δ13C values are affected by several biological and environmental factors during starvation, but the generality of the effect of starvation on δ15N and δ13C values has not yet been tested. Here, we performed a meta-analysis to e...

Stable nitrogen isotope ratios are routinely used to disentangle trophic relationships. Several authors have discussed factors in addition to diet that might contribute to variability in δ15N of consumers, but few studies have explored such factors in detail. For a better understanding of tissue-specific differences in δ15N, we examined postlarval euphausiids across a variety of seasons and reg...

Understanding of the nitrogen (N) cycle and its spatial variability is important for managing ecosystems. Soil δ15N, as an important indicator of different soil nitrogen cycling processes, may provide critical information about the spatial variability in soil N cycling. The objective of this study was to examine the dominant landscape scale variability of δ15N, the location of the variability a...

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 ...

Body tissues are generally 15N-enriched over the diet, with a discrimination factor (Δ15N) that varies among tissues and individuals as a function of their nutritional and physiopathological condition. However, both 15N bioaccumulation and intra- and inter-individual Δ15N variations are still poorly understood, so that theoretical models are required to understand their underlying mechanisms. U...

Interand intra-site comparisons of the nitrogen (N) stable isotope composition of wetland plant species have been used to identify sources of N in coastal areas. In this study, we compared δ15N values from diff erent herbaceous wetland plants across 34 diff erent coastal wetlands from the fi ve main Hawaiian Islands and investigated relationships of δ15N with land use, human population density,...

Denitrification and nitrogen-fixation processes in the marine environment have been intensively studied, particularly how these processes affect the nitrogen stable-isotope signature (δ15N) of inorganic nutrients and organisms at the base of the food web. However, the assumption that these δ15N differences at the base of food webs are reflected in higher trophic-level organisms has not been wid...

Lipid extraction of biomass prior to stable isotope analysis is known to cause variable changes in the stable nitrogen isotopic composition (δ15N) of residual biomass. However, the underlying factors causing these changes are not yet clear. Here we address this issue by comparing the δ15N of bulk and residual biomass of several marine animal tissues (fish, crab, cockle, oyster, and polychaete),...