Data from: Amino acid δ15N underestimation of cetacean trophic positions highlights poor understanding of isotopic fractionation in higher marine consumers ...

• Main Authors: Matthews, Cory, Ruiz-Cooley, Iliana, Pomerleau, Corinne, Ferguson, Steven
• Format: Dataset
• Language: English
• Published: Dryad 2020
• Subjects: Amino acids; isotopic fractionation; marine consumers; Ferguson; Beluga; Beluga*; bowhead whale; Killer Whale; Sperm whale; Killer whale
• Online Access: https://dx.doi.org/10.5061/dryad.9kd51c5d3; https://datadryad.org/stash/dataset/doi:10.5061/dryad.9kd51c5d3

Compound specific stable isotope analysis (CSIA) of amino acids (AAs) has been rapidly incorporated in ecological studies to resolve consumer trophic position (TP). Differential 15N fractionation of ‘trophic’ AAs, which undergo 15N enrichment with each trophic step, and ‘source’ AAs, which undergo minimal trophic 15N enrichment and serve as a proxy for primary producer δ15N values, allows for internal calibration of TP. Recent studies, however, have shown the difference between source and trophic AA δ15N values in higher marine consumers is less than predicted from empirical studies of invertebrates and fish. To evaluate CSIA-AA for estimating TP of cetaceans, we compared source and trophic AA δ15N values of multiple tissues (skin, baleen, and dentine collagen) from five species representing a range of TPs: bowhead whales, beluga whales, short-beaked common dolphins, sperm whales, and fish-eating (FE) and marine mammal-eating (MME) killer whale ecotypes. TP estimates (TPCSIA) using several ... : Most of the isotope data presented here have been compiled from previously published studies where detailed sample preparation and analysis procedures can be found (Matthews and Ferguson 2014, 2015; Ruiz-Cooley et al. 2014, 2017; Pomerleau et al. 2017; Zupcic-Moore et al. 2017). Briefly, baleen samples were drilled from the proximal end of each plate where the most recent growth corresponds to foraging on the summer grounds (Matthews and Ferguson 2015), and no further sample preparation was carried out prior to isotope analysis. Bowhead whale skin samples were rinsed of DMSO using deionized water and were not lipid-extracted prior to analysis. Sperm whale skin samples were also rinsed of DMSO using deionized water, and then lipid-extracted using a 2:1 chloroform ethanol mixture (Lesage et al. 2010; Ruiz-Cooley et al. 2012). Dolphin skin was thawed and lipid-extracted with petroleum ether. Annual dentine growth layers of sperm whale teeth were sampled using a micromill and later combined, while a handheld ...