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Stable‐hydrogen isotope heterogeneity in keratinous materials: mass spectrometry and migratory wildlife tissue subsampling strategies
Author(s) -
Wassenaar Leonard I.,
Hobson Keith A.
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2626
Subject(s) - feather , isotope analysis , isotope , wildlife , hydrogen isotope , stable isotope ratio , chemistry , range (aeronautics) , isotope ratio mass spectrometry , ecology , zoology , mass spectrometry , biology , hydrogen , chromatography , composite material , physics , materials science , organic chemistry , quantum mechanics
Stable‐hydrogen isotope measurements ( δ D) of biological tissues have gained widespread acceptance in wildlife and forensic studies, especially in tracking geographical movements of birds and other species. Continuous‐flow isotope‐ratio mass spectrometry enables high‐throughput δ D analyses to be conducted on tissue samples as small as 0.15 mg, compared with conventional offline analyses that require 7–10 mg. This reduction in sample size has raised concerns regarding intra‐sample hydrogen isotopic variance due to potential biological heterogeneities that could exceed interpretations of geospatial origin. To help resolve this, feathers were obtained from captive birds to examine isotopic variance expected due to sample size, location, and heterogeneity factors, and from selected wild birds to examine isotopic variance due to these and to additional dietary or location changes during feather growth. Captive bird feathers were sub‐sampled along the vane on either side of a single feather at masses of 0.25, 0.35, 0.45, 0.6, 1.0 and 2.0 mg, and along the rachis. The results showed consistency of feather δ D measurements across a wide range of sample masses. Within‐feather δ D isotopic variance for captive and some wild birds was as low as ±3‰ for vane material, which corresponds to a geospatial resolution of about 1 degree of latitude in central North America. Intra‐sample variance for the rachis was ±5‰, with lower δ D values for both wild and captive birds. However, given the extraordinary intra‐feather δ D variance observed in some wild species, we recommend researchers first carefully assess the degree of intra‐ and inter‐sample hydrogen isotopic variation in the selected tissue growth period for the species of interest before geospatial interpretations of origin are attempted. Copyright © 2006 John Wiley & Sons, Ltd.