scholarly journals Effect of Different Derivatization Protocols on the Calculation of Trophic Position Using Amino Acids Compound-Specific Stable Isotopes

2020 ◽  
Vol 7 ◽  
Author(s):  
Stephane Martinez ◽  
Maya Lalzar ◽  
Eli Shemesh ◽  
Shai Einbinder ◽  
Beverly Goodman Tchernov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Amino Acid ◽  
Nitrogen Atom ◽  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Nitrogen Stable Isotope ◽  
Exogenous Nitrogen

Amino acids compound-specific nitrogen stable isotope analysis (AA-CSIA) is an emerging tool in ecology for understanding trophic system dynamics. While it has been successfully used for several independent studies across a range of environments and study locations, researchers have encountered calculation issues for determining trophic position values. Most studies introduce modifications to the constants of trophic position equation calculations, but then fail to account for the equation variations when comparing across separate research studies. The broad acceptance of this approach is anchored in an underlying presumption that no addition of the exogenous nitrogen atom occurs in the different methods; and therefore, such variations should not affect the outcome. In this paper, we evaluate the use of the EZfaast amino acid derivatization kit (chloroformate) and compare it to the isotopic results of two other derivatization methods. We highlight new considerations for working with AA-CSIA that might account for some of the variations in the results and lead researchers to modify constants in the equation. This study concludes that developing unique constants per derivatization method is required to have more accurate cross-study comparisons of trophic positions.

scholarly journals Effect of different derivatization protocols on the calculation of trophic position using amino acids compound-specific stable isotopes

2020 ◽  
Author(s):  
Stephane Martinez ◽  
Maya Lalzer ◽  
Eli Shemesh ◽  
Shai Einbinder ◽  
Beverly Goodman Tchernov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stable Isotopes ◽  
Amino Acid ◽  
Nitrogen Atom ◽  
Stable Isotope ◽  
System Dynamics ◽  
Trophic Position ◽  
Nitrogen Stable Isotope ◽  
Exogenous Nitrogen ◽  
Research Studies

AbstractAmino acids compound-specific nitrogen stable isotope (AA-CSIA) is an emerging tool in ecology for understanding trophic system dynamics. While it has been successfully used for several independent studies across a range of environments and study locations, researchers have encountered calculation issues for determining trophic position values. Most studies introduce modifications to the constants of trophic position equation calculations, but then fail to account for the equation variations when comparing the results of separate research studies. The acceptance of this approach is related to the underlying presumption that no addition of the exogenous nitrogen atom occurs in the different methods and, therefore, such variations should not affect the outcome. In this paper, we evaluate the use of the EZfaast amino acid derivatization kit (chloroformate) and compare it to the isotopic results of two other derivatization methods. We highlight new considerations for working with AA-CSIA that might account for some of the variations in the results and lead researchers to modify constants in the equation. This likely requires developing the unique constants per derivatization method in order to be able to compare the trophic position results across different studies.

scholarly journals Stable nitrogen isotope analysis of amino acids as a new tool to clarify complex parasite-host interactions within marine food webs

2021 ◽  
Author(s):  
Philip Riekenberg ◽  
Tijs Joling ◽  
Lonneke L. IJsseldijk ◽  
Andreas M. Waser ◽  
Marcel van der Meer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Stable Isotope ◽  
Food Webs ◽  
Stable Isotope Analysis ◽  
Trophic Interactions ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Isotopic Analysis ◽  
Parasitic Interactions

AbstractTraditional bulk isotopic analysis is a pivotal tool for mapping consumer-resource interactions in food webs but has largely failed to adequately describe parasite-host relationships. Thus, parasite-host interactions remain largely understudied in food web frameworks despite these relationships increasing linkage density, connectance, and ecosystem biomass. Compound-specific stable isotopes from amino acids provides a promising novel approach that may aid in mapping parasitic interactions in food webs. However, to date it has not been applied to parasitic trophic interactions.Here we use a combination of traditional bulk stable isotope analyses and compound-specific isotopic analysis of the nitrogen in amino acids to examine resource use and trophic interactions of five parasites from three hosts from a marine coastal food web (Wadden Sea, European Atlantic). By comparing isotopic compositions of bulk and amino acid nitrogen, we aimed to characterize isotopic fractionation occurring between parasites and their hosts and to clarify the trophic position of the parasites.Our results showed that parasitic trophic interactions were more accurately identified when using compound-specific stable isotope analysis due to removal of underlying source isotopic variation for both parasites and hosts, and avoidance of the averaging of amino acid variability in bulk analyses through use of multiple trophic amino acids. The compound-specific method provided clear trophic discrimination factors in comparison to bulk isotope methods, however, those differences varied significantly among parasite species.Amino acid compound specific isotope analysis has widely been applied to examine trophic position within food webs, but our analyses suggest that the method is particularly useful for clarifying the feeding strategies for parasitic species. Baseline isotopic information provided by source amino acids allows clear identification of the fractionation occurring due to parasite metabolism by integrating underlying isotopic variations from the host tissues. However, like for bulk isotope analysis, the application of a universal trophic discrimination factor to parasite-host relationships remains inappropriate for compound-specific stable isotope analysis. Despite this limitation, compound-specific stable isotope analysis is and will continue to be a valuable tool to increase our understanding of parasitic interactions in marine food webs.

scholarly journals Bone stable isotope evidence for infant feeding in Mediaeval England

Antiquity ◽  
2002 ◽  
Vol 76 (293) ◽  
pp. 654-656 ◽  
Author(s):  
S.A. Mays ◽  
M.P. Richards ◽  
B.T. Fuller
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Infant Feeding ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Nitrogen Stable Isotope ◽  
Documentary Sources ◽  
Isotope Evidence ◽  
Duration Of Breastfeeding

This paper is a first study of duration of breastfeeding using bone stable isotopes in infants in a British palaeopopulation, from the deserted Mediaeval village of Wharram Percy, England. Nitrogen stable isotope analysis suggests cessation of breastfeeding between 1 and 2 years of age. Comparison with Mediaeval documentary sources suggests that recommendations of physicians regarding infant feeding may have influenced common practice in this period.

Land‐use change erodes trophic redundancy in tropical forest streams: evidence from amino acid stable isotope analysis

2021 ◽  
Author(s):  
Kenny W.J. Chua ◽  
Jia Huan Liew ◽  
Clare L. Wilkinson ◽  
Amirrudin B. Ahmad ◽  
Heok Hui Tan ◽  
...  
Keyword(s):  
Land Use ◽  
Amino Acid ◽  
Stable Isotope ◽  
Land Use Change ◽  
Tropical Forest ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Forest Streams ◽  
Acid Stable

Diet of spotted bats (Euderma maculatum) in Arizona as indicated by fecal analysis and stable isotopes

2009 ◽  
Vol 87 (10) ◽  
pp. 865-875 ◽  
Author(s):  
M. L. Painter ◽  
C. L. Chambers ◽  
M. Siders ◽  
R. R. Doucett ◽  
J. O. Whitaker, Jr. ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Latitudinal Gradient ◽  
Visual Analysis ◽  
Isotope Analysis ◽  
Stable Carbon ◽  
Fecal Analysis ◽  
Insect Prey ◽  
Wing Hair

We assessed diet of spotted bats ( Euderma maculatum (J.A. Allen, 1891)) by visual analysis of bat feces and stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of bat feces, wing, hair, and insect prey. We collected 33 fecal samples from spotted bats and trapped 3755 insects where bats foraged. Lepidopterans averaged 99.6% of feces by volume; other insects were not a major component of diet. The δ13C and δ15N values of bat feces were similar to those of moths from families Noctuidae (N), Lasiocampidae (L), and Geometridae (G), but differed from Arctiidae (A) and Sphingidae (S). We used a mixing model to reconstruct diet; three families (N, L, G) represented the majority (88%–100%) of the diet with A + S representing 0%–12%. Although we compared δ13C and δ15N values of wing, hair, and feces of spotted bats, feces best represented recent diet; wing and hair were more enriched than feces by 3‰ and 6‰, respectively. This pattern was consistent with that reported for other bat species. We suggest that spotted bats persist across a wide latitudinal gradient partly because they can forage on a variety of noctuid, geometrid, and lasiocampid moths. Using visual fecal inspection with stable isotope analysis provided information on families of moths consumed by an uncommon bat species.

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