Premium
An evaluation of lipid extraction techniques for interpretation of carbon and nitrogen isotope values in bottlenose dolphin ( Tursiops truncatus ) skin tissue
Author(s) -
Wilson Rachel Marie,
Chanton Jeffrey P.,
Balmer Brian C.,
Nowacek Douglas P.
Publication year - 2014
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12018
Subject(s) - bottlenose dolphin , extraction (chemistry) , δ13c , isotope , chloroform , normalization (sociology) , isotopes of carbon , stable isotope ratio , solvent , chromatography , chemistry , biology , zoology , environmental chemistry , fishery , total organic carbon , biochemistry , physics , quantum mechanics , sociology , anthropology
We studied the effects of two common chemical extraction techniques on bottlenose dolphin ( Tursiops truncatus ) skin tissues with the intent to develop a mathematical lipid correction for dolphin skin δ 13 C. One method employs a hot solvent mixture (chloroform and methanol) while the other method requires washing the samples with cold solvent followed by water. The water wash method resulted in significant alteration of tissue δ 15 N. We found no correlation between change in sample mass and C/N or between change in sample mass and the change in δ 13 C (Δδ 13 C) following lipid extraction. Although Δδ 13 C was positive following lipid extraction (mean = 1.6‰ and 1.2‰, for the two methods), there was no correlation between C/N and Δδ 13 C for either method. Cumulatively, these results prevented us from applying a mathematical lipid normalization. Based on our findings and consideration of previously reported results, we suggest that applying these extraction techniques to dolphin skin with C/N < 4.5 introduces greater uncertainty than is warranted. We recommend against lipid correction for dolphin skins with C/N < 4.5, but stress that the resulting uncertainty in δ 13 C needs to be accounted for when implementing isotope mixing models to assess diet or organic matter sources.