Stable isotope ratios (typically of carbon and nitrogen) provide one representation of an organism's trophic niche and are widely used to examine aspects of food web structure. Yet stable isotopes have not been applied to quantitatively characterize community-wide aspects of trophic structure (i.e., at the level of an entire food web). We propose quantitative metrics that can be used to this en...

In recent years stable isotopes of metallic and semi-metallic elements have become popular as tracers in studies of nutrition and metabolism. There are several recent reviews on the use of stable isotopes of the mineral elements (Janghorbani & Young, 1980; Janghorbani et af . 1985). The orientation of these reviews has tended toward neutron-activation analysis in conjunction with the faecal iso...

In recent years stable isotopes of metallic and semi-metallic elements have become popular as tracers in studies of nutrition and metabolism. There are several recent reviews on the use of stable isotopes of the mineral elements (Janghorbani & Young, 1980; Janghorbani et af . 1985). The orientation of these reviews has tended toward neutron-activation analysis in conjunction with the faecal iso...

Inflow of matter and organisms may strongly affect the local density and diversity of organisms. This effect is particularly evident on shores where organisms with aquatic larval stages enter the terrestrial food web. The identities of such trophic links are not easily estimated as spiders, a dominant group of shoreline predator, have external digestion. We compared trophic links and the prey d...

INTRODUCTIONA general approach in quantitative mass spectrometry is to mix a protein sample containing only natural-abundance isotopes with an identical protein sample containing proteins labeled with heavy stable isotopes (e.g., (2)H, (13)C, (15)N, or (18)O). Introduction of stable isotope labels into proteins alters their molecular weight and such changes can be observed on the mass spectrome...

Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic B. A. Hook, J. Halfar, Z. Gedalof, J. Bollmann, and D. Schulze Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada Department of Geog...

Eastern boundary currents are often described as 'wasp-waist' ecosystems in which one or few mid-level forage species support a high diversity of larger predators that are highly susceptible to fluctuations in prey biomass. The assumption of wasp-waist control has not been empirically tested in all such ecosystems. This study used stable isotope analysis to test the hypothesis of wasp-waist con...

Stable isotopes and their potential for detecting various and complex ecosystem processes are attracting an increasing number of scientists. Progress is challenging, particularly under global change scenarios, but some established views have been challenged. The IX meeting of the Spanish Association of Terrestrial Ecology (AAET, Ubeda, 18-22 October 2009) hosted a symposium on the ecology of st...

for this study, asmari (oligo-miocene) and bangestan (cretaceous) reservoir oils from themarun oilfield were studied geochemically. gas chromatograms and stable isotopes of carbon and sulfur indifferent oil fractions were studied. normal alkanes nc15+ are as high as 93% with a saturate percentage up to53.9% which reveal a high maturity of asmari and bangestan reservoir paraffinic oils. carbon p...