نتایج جستجو برای: δ13c

تعداد نتایج: 1653  

2015
Fabiene Maria Jesus Marcelo Ribeiro Pereira Cassiano Sousa Rosa Marcelo Zacharias Moreira Carlos Frankl Sperber Tony Robillard

Stable isotope analysis (SIA) is an important tool for investigation of animal dietary habits for determination of feeding niche. Ideally, fresh samples should be used for isotopic analysis, but logistics frequently demands preservation of organisms for analysis at a later time. The goal of this study was to establish the best methodology for preserving forest litter-dwelling crickets for later...

2003
David R. Bowling Diane E. Pataki James R. Ehleringer

Isotopic net ecosystem exchange (isofluxes, or flux densities of CO2) can be combined with standard eddy covariance methods to partition net ecosystem exchange of carbon dioxide (F) into its component one-way fluxes, photosynthesis and respiration. At present, the approaches used to estimate isotopic fluxes are labor-intensive and dependent on several assumptions. To assess the relative utility...

2016
Scott J. Werner Keith A. Hobson Steven L. Van Wilgenburg Justin W. Fischer

We analyzed stable-hydrogen (δ2H), carbon (δ13C) and nitrogen (δ 15N) isotope ratios in feathers to better understand the molt origin and food habits of Red-winged Blackbirds (Agelaius phoeniceus) near sunflower production in the Upper Midwest and rice production in the Mid-South of the United States. Outer primary feathers were used from 661 after-second-year (ASY) male blackbirds collected in...

2003
Jamie E. ELSILA Daniel P. GLAVIN Jason P. DWORKIN

available online at http://meteoritics.org Cometary glycine detected in samples returned by Stardust Jamie E. ELSILA*, Daniel P. GLAVIN, and Jason P. DWORKIN NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA *Corresponding author: [email protected] (Received 05 June 2009; revision accepted 24 July 2009) Abstract–Our previous analysis of cometary samples returned to Earth by N...

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 ...

2006
April Hedd William A. Montevecchi

We combined conventional dietary sampling (2002) with stable isotope analysis of nitrogen (δ15N) and carbon (δ13C) in feathers of Leach’s storm-petrels Oceanodroma leucorhoa (2001 and 2002) to investigate temporal, sexand age-related variation in diet and trophic position, at Baccalieu Island, Newfoundland, Canada. Nestlings are fed mainly fish and crustaceans (ca. 90 and 9% by mass, respective...

2018
Farnoush Tahmasebi Fred J Longstaffe Grant Zazula

A magnificent repository of Late Pleistocene terrestrial megafauna fossils is contained in ice-rich loess deposits of Alaska and Yukon, collectively eastern Beringia. The stable carbon (δ13C) and nitrogen (δ15N) isotope compositions of bone collagen from these fossils are routinely used to determine paleodiet and reconstruct the paleoecosystem. This approach requires consideration of changes in...

2009
Michael J. Risk Owen A. Sherwood Rob Nairn Chris Gibbons

In 2007, a study was undertaken of the long-term records of the ratios of stable isotopes of carbon (δ13C) and nitrogen (δ15N) in the skeletons of antipatharians (black corals) growing on reefs near the city of Jeddah, Saudi Arabia. Antipatharians were collected from more than 100 sites, and detailed records obtained from 31 individuals from 16 sites. Annual growth bands were identified and cou...

2009
Aimee E Pusz Kenneth G Miller James D Wright Miriam E Katz Benjamin S Cramer Dennis V Kent Aimee E. Pusz Kenneth G. Miller James D. Wright Miriam E. Katz Benjamin S. Cramer

We evaluated the age of two Upper Eocene impact ejecta layers (North American microtektites linked to the Chesapeake Bay impact structure and clinopyroxene [cpx] spherules from the Popigai crater) and the global effects of the associated impact events. The reported occurrence of cpx spherules from the Popigai impact structure at South Atlantic ODP Site 1090 within the middle of magnetochron C16...

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...

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