Estimating tissue-specific discrimination factors and turnover rates of stable isotopes of nitrogen and carbon in the smallnose fanskate Sympterygia bonapartii (Rajidae)

2016 ◽  
Vol 89 (2) ◽  
pp. 1258-1270 ◽  
Author(s):  
D. E. Galván ◽  
J. Jañez ◽  
A. J. Irigoyen
Keyword(s):  
Stable Isotopes ◽  
Turnover Rates ◽  
Tissue Specific ◽  
Discrimination Factors

Isotopic fractionation and turnover in captive Garden Warblers (Sylvia borin): implications for delineating dietary and migratory associations in wild passerines

2003 ◽  
Vol 81 (9) ◽  
pp. 1630-1635 ◽  
Author(s):  
Keith A Hobson ◽  
Franz Bairlein
Keyword(s):  
Stable Isotopes ◽  
Isotopic Fractionation ◽  
Carbon Turnover ◽  
Stable Carbon ◽  
Turnover Rates ◽  
Exponential Decay Model ◽  
N Isotopes ◽  
Discrimination Factors ◽  
Sylvia Borin ◽  
Element Turnover

There is currently a great deal of interest in using stable-isotope methods to investigate diet and migratory connections in wild passerines. To apply these methods successfully, it is important to understand how stable isotopes discriminate or change between diet and the tissue of interest and what the element-turnover rates are in metabolically active tissues. Of particular use are studies that sample birds non-destructively through the use of blood and feathers. We investigated patterns of isotopic discrimination between diet and blood and feathers of Garden Warblers (Sylvia borin) raised on an isotopically homogeneous diet (48% C, 5% N) and then switched to one of two experimental diets, mealworms (56.8% C, 8.3% N) and elderberries, Sambucus niger (47.4% C, 1.5% N). We established that the discrimination factors between diet and blood appropriate for stable carbon (δ13C) and nitrogen (δ15N) isotopes are +1.7‰ and +2.4‰, respectively. For feathers, these values were +2.7‰ and +4‰, respectively. Turnover of elemental nitrogen in whole blood was best approximated by an exponential-decay model with a half-life of 11.0 ± 0.8 days (mean ± SD). Corresponding turnover of carbon was estimated to range from 5.0 ± 0.7 to 5.7 ± 0.8 days. We conclude that this decoupling of nitrogen- and carbon-turnover rates can be explained by differences in metabolic routing of dietary macromolecules. Our results suggest that tracking frugivory in migratory passerines that switch diets between insects and fruits may be complicated if only a trophic-level estimate is made using δ15N measurements.

scholarly journals Isotopic discrimination factors and nitrogen turnover rates in reared Atlantic bluefin tuna larvae (Thunnus thynnus): effects of maternal transmission

2016 ◽  
Vol 80 (4) ◽  
pp. 447 ◽  
Author(s):  
Amaya Uriarte ◽  
Alberto García ◽  
Aurelio Ortega ◽  
Fernando De la Gándara ◽  
José Quintanilla ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Bluefin Tuna ◽  
Gilthead Seabream ◽  
Half Time ◽  
Turnover Rates ◽  
Thunnus Thynnus ◽  
Data Set ◽  
Nitrogen Turnover ◽  
Discrimination Factors

The use of stable isotope analysis to study animal diets requires estimates of isotopic turnover rates (half time, t50) and discrimination factors (Δ) for an accurate interpretation of trophic patterns. The stable isotopes of carbon and nitrogen were analysed for eggs and reared larvae of Thunnus thynnus, as well as for the different diets supplied during the experiment. The results showed high values of δ15N in eggs and larvae (n=646) until 4 DAH. After this time lapse, the stable isotope values declined progressively until 12 DAH, when notochord flexion began. The δ13C showed an inverse trend, suggesting that maternal inheritance of the stable isotopes is evident until pre-flexion stages. This study proposes a model for estimating maternal isotopic signatures of bluefin broodstock. After notochord flexion, larvae were fed with aquaculture-bred gilthead seabream, which resulted in a rapid increase of bluefin larvae δ15N values together with a rapid decrease in δ13C values. The estimated nitrogen half-time to reach the steady state from the diet was 2.5±0.3 days and the discrimination factor was 0.4±0.3(‰). These results represent the first data set that has allowed isotopic nitrogen turnover rates and discrimination factors of the larval stages of bluefin tuna to be estimated.

Tissue-specific isotope turnover and discrimination factors are affected by diet quality and lipid content in an omnivorous consumer

2016 ◽  
Vol 479 ◽  
pp. 35-45 ◽  
Author(s):  
John A. Mohan ◽  
Stephanie D. Smith ◽  
Tara L. Connelly ◽  
Eric T. Attwood ◽  
James W. McClelland ◽  
...  
Keyword(s):  
Lipid Content ◽  
Diet Quality ◽  
Tissue Specific ◽  
Isotope Turnover ◽  
Discrimination Factors

Tissue-specific isotope trophic discrimination factors and turnover rates in a marine elasmobranch: empirical and modeling results

2012 ◽  
Vol 69 (3) ◽  
pp. 551-564 ◽  
Author(s):  
Luis Malpica-Cruz ◽  
Sharon Z. Herzka ◽  
Oscar Sosa-Nishizaki ◽  
Juan Pablo Lazo
Keyword(s):  
Natural Populations ◽  
Nitrogen Isotope ◽  
Cartilage Tissue ◽  
Turnover Rates ◽  
Isotopic Equilibrium ◽  
Isotope Turnover ◽  
Discrimination Factors ◽  
Triakis Semifasciata ◽  
Leopard Sharks ◽  
Trophic Discrimination

There are very few studies reporting isotopic trophic discrimination factors and turnover rates for marine elasmobranchs. A controlled laboratory experiment was conducted to estimate carbon and nitrogen isotope trophic discrimination factors and isotope turnover rates for blood, liver, muscle, cartilage tissue, and fin samples of neonate to young-of-the-year leopard sharks ( Triakis semifasciata ). Trophic discrimination factors varied (0.13‰–1.98‰ for δ13C and 1.08‰–1.76‰ for δ15N). Tissues reached or were close to isotopic equilibrium to the new diet after about a threefold biomass gain and 192 days. Liver and blood exhibited faster isotope turnover than muscle, cartilage tissue, and fin samples, and carbon isotopes turned over faster than those of nitrogen. Metabolic turnover contributed substantially to isotopic turnover, which differs from most reports for young marine teleosts. We modeled the relationship between muscle turnover rates and shark size by coupling laboratory results with growth rate estimates for natural populations. Model predictions for small, medium, and large wild leopard sharks indicate the time to isotopic equilibrium is from one to several years.

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