نتایج جستجو برای: δ15n

تعداد نتایج: 888  

2014
Gabriele A. Macho Julia A. Lee-Thorp

Factors influencing the hominoid life histories are poorly understood, and little is known about how ecological conditions modulate the pace of their development. Yet our limited understanding of these interactions underpins life history interpretations in extinct hominins. Here we determined the synchronisation of dental mineralization/eruption with brain size in a 20th century museum collecti...

2014
Rocio I. Ruiz-Cooley Paul L. Koch Paul C. Fiedler Matthew D. McCarthy Wei-Chun Chin

Climatic variation alters biochemical and ecological processes, but it is difficult both to quantify the magnitude of such changes, and to differentiate long-term shifts from inter-annual variability. Here, we simultaneously quantify decade-scale isotopic variability at the lowest and highest trophic positions in the offshore California Current System (CCS) by measuring δ15N and δ13C values of ...

2017
Fernando Barreto-Curiel Ulfert Focken Louis R D'Abramo María Teresa Viana

Fish starvation is defined as food deprivation for a long period of time, such that physiological processes become confined to basal metabolism. Starvation provides insights in physiological processes without interference from unknown factors in digestion and nutrient absorption occurring in fed state. Juveniles of amberjack Seriola lalandi were isotopically equilibrated to a formulated diet fo...

2015
Yuri Gori Ron Wehrens Nicola La Porta Federica Camin

BACKGROUND Tracking timber is necessary in order to prevent illegal logging and protect local timber production, but there is as yet no suitable analytical traceability method. Stable isotope ratios in plants are known to reflect geographical variations. In this study we analysed four stable isotope ratios in order to develop a model able to identify the geographic origin of Norway spruce in th...

2016
Julia Beaumont Janet Montgomery

The major components of human diet both past and present may be estimated by measuring the carbon and nitrogen isotope ratios (δ13C and δ15N) of the collagenous proteins in bone and tooth dentine. However, the results from these two tissues differ substantially: bone collagen records a multi-year average whilst primary dentine records and retains time-bound isotope ratios deriving from the peri...

2012
L. A. Hückstädt J. M. Burns P. L. Koch B. I. McDonald D. E. Crocker D. P. Costa

Although crabeater seals Lobodon carcinophaga are among the most abundant consumers of Antarctic krill Euphausia superba, their diet has rarely been studied throughout most of the species’ range. Using δ13C and δ15N values in vibrissae from 53 seals, we examined the trophic ecology of crabeater seals from the western Antarctic Peninsula (wAP) in 2001, 2002 and 2007. We observed a wide variabili...

2018
G.E. Bebout N.R. Banerjee M.R.M. Izawa K. Kobayashi K. Lazzeri L.A. Ranieri E. Nakamura

Observed enrichments of N (and the δ15N of this N) in volcanic glasses altered on Earth's modern and ancient seafloor are relevant in considerations of modern global N subduction fluxes and ancient life on Earth, and similarly altered glasses on Mars and other extraterrestrial bodies could serve as valuable tracers of biogeochemical processes. Palagonitized glasses and whole-rock samples of vol...

2016
Iana Gritcan Mark Duxbury Sebastian Leuzinger Andrea C. Alfaro

We measured nitrogen stable isotope values (δ15N), and total phosphorus (%P) and total nitrogen (%N) contents in leaves of the temperate mangrove (Avicennia marina sp. australasica) from three coastal ecosystems exposed to various levels of human impact (Manukau, high; Mangawhai, low; and Waitemata, intermediate) in northern New Zealand. We measured δ15N values around 10‰ in environments where ...

2017
Elizabeth Yohannes Karl-Otto Rothhaupt

Understanding the ecological patterns of invasive species and their habitats require an understanding of the species' foraging ecology. Stable carbon (δ13C) and nitrogen (δ15N) isotope values provide useful information into the study of animal ecology and evolution, since the isotope ratios of consumers reflect consumer's dietary patterns. Nevertheless, the lack of species- and element-specific...

2017
Carolin Dittrich Ulrich Struck Mark-Oliver Rödel

Consumption of frog legs is increasing worldwide, with potentially dramatic effects for ecosystems. More and more functioning frog farms are reported to exist. However, due to the lack of reliable methods to distinguish farmed from wild-caught individuals, the origin of frogs in the international trade is often uncertain. Here, we present a new methodological approach to this problem. We invest...

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