Technical Note: Calcium and carbon stable isotope ratios as paleodietary indicators

Melin, Amanda D.; Crowley, Brooke E.; Brown, S. T.; Wheatley, Patrick V.; Moritz, Gillian L.; Yu, Fred Tuh Yit; Bernard, Henry; DePaolo, Donald J.; Jacobson, Andrew D.; Dominy, Nathaniel J.

doi:10.1002/ajpa.22530

Cited by 34 publications

(24 citation statements)

References 78 publications

(123 reference statements)

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“…Melin et al . () analysed two modern terrestrial mammalian faunas but did not find significant trophic level effects. However, their study highlighted the necessity of using calcium isotopes in conjunction with other isotope proxies, such as carbon.…”

Section: Non‐traditional Isotopes In Modern Faunasmentioning

confidence: 94%

Non‐traditional isotope perspectives in vertebrate palaeobiology

2017

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The recent development of Multi-Collector Inductively Coupled PlasmaMass Spectrometry (MC-ICPMS), notably in the disciplines of earth sciences, now allows the measurement of precise isotope ratios, even under low concentration. Nontraditional isotope systems, such as alkaline earth (Ca, Mg) and transition (Cu, Fe, Zn) metals are now being measured in a variety of biological tissues, including bone and teeth. Although our understanding of the environmental and biological mechanisms behind the fractionation of such elements is still in its infancy, some of these isotopes are suspected to fractionate along the food chain as has been reported in the literature for calcium, magnesium and zinc. Other geochemical methods, such as concentration analyses permit a prior assessment of diagenesis in the fossils to be analysed and such an approach allows recognising that in some circumstances, not only enamel but also dentine or bone can preserve its original biogenic composition. The aims here are to review the current knowledge surrounding these various isotopic tools, address their potential preservation in biological apatite and provide the palaeobiologist a guide on the different toolkits available and discuss their potential applications in vertebrate palaeobiology with a case study involving two mammal assemblages from the Pleistocene of Europe.Key words: non-traditional isotopes, palaeobiology, calcium, cave bear, Pleistocene.GEOCHEMICAL tools are a great asset to infer biological characteristics in fossil organisms that otherwise would remain completely unnoticed with morphological 2 observations alone. Among stable isotopes, carbon (C), oxygen (O) and nitrogen (N) have been and are still widely used in ecology, archaeology and in palaeoecology.From the vertebrate individual organism to the community, it is possible to reconstruct body temperatures and infer thermophysiology, reconstruct ambient palaeoenvironmental conditions and infer habitat use and migrations; and last but not least to reconstruct diet and trophic structures in ancient food webs. Most isotope approaches rely on stable isotope ratios of carbon and oxygen but also on radiogenic strontium preserved in fossilised tooth and bone. Elemental concentrations have also proved useful in many contexts such as dietary inference. For example, elemental ratios of strontium to calcium or barium to calcium allow reconstructing ecosystem structures.Contrary to light isotope systems, which have a variability beyond 10 ‰, nontraditional isotopes comprising alkaline earths (Ca, Mg) or transition metals (Cu, Fe, Zn), show isotope variability within a maximum range of 2-3‰. Recent analytical progresses from the domains of earth sciences now allow the measurement of such stable isotope systems, which show limited fractionation and require high precision and accuracy of measurements from mass spectrometers. The main basis for all those geochemical applications is already starting to be applied to archaeological studies (see review by Jaouen and Pons, 2016...

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Section: Non‐traditional Isotopes In Modern Faunasmentioning

confidence: 94%

Non‐traditional isotope perspectives in vertebrate palaeobiology

2017

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“…Trophic-level studies in modern and past environments using Ca isotopes are promising but are confronted with poorly understood residual variability both in terrestrial and marine environments (37,56). These studies are based on observed isotopic offsets in δ 44/42 Ca varying between −0.14‰ and −0.65‰ from one trophic level to another (37,42,57).…”

Section: Ca Isotope Composition Of Postnatal Diet and Influence Of Brmentioning

confidence: 99%

Assessing human weaning practices with calcium isotopes in tooth enamel

Tacail

Thivichon-Prince

Martin

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Weaning practices differ among great apes and likely diverged during the course of human evolution, but behavioral inference from the fossil record is hampered by a lack of unambiguous biomarkers. Here, we show that early-life dietary transitions are recorded in human deciduous tooth enamel as marked variations in Ca isotope ratios (δ 44/42 Ca). Using a sequential microsampling method along the enamel growth axis, we collected more than 150 enamel microsamples from 51 deciduous teeth of 12 different modern human individuals of known dietary histories, as well as nine enamel samples from permanent third molars. We measured and reconstructed the evolution of 44 Ca/ 42 Ca ratios in enamel from in utero development to first months of postnatal development. We show that the observed variations of δ 44/42 Ca record a transition from placental nutrition to an adult-like diet and that Ca isotopes reflect the duration of the breastfeeding period experienced by each infant. Typically, the δ 44/42 Ca values of individuals briefly or not breastfed show a systematic increase during the first 5-10 mo, whereas individuals with long breastfeeding histories display no measurable variation in δ 44/42 Ca of enamel formed during this time. The use of Ca isotope analysis in tooth enamel allows microsampling and offers an independent approach to tackle challenging questions related to past population dynamics and evolution of weaning practices in hominins.calcium isotopes | tooth enamel | dietary transitions | weaning | breast milk

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“…[1][2][3][4][5][6] Many studies employ "double-spike" techniques to correct for instrumental mass-fractionation when analyzing 40 Ca/ 44 Ca ratios by multi collector-thermal ionization mass spectrometry (MC-TIMS). The details and virtues of double-spiking have been extensively discussed in several publications.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a ⁴⁸Ca–⁴³Ca double-spike MC-TIMS method for measuring Ca isotope ratios (δ^44/40Ca and δ^44/42Ca): limitations from filament reservoir mixing

Lehn

Jacobson

2015

J. Anal. At. Spectrom.

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We used a Monte Carlo error model to optimize a 48 Ca-43 Ca double-spike technique for measuring Ca isotope ratios (d 44/40 Ca and d 44/42 Ca) by Multi-Collector Thermal Ionization Mass Spectrometry (MC-TIMS). The model considers errors for counting statistics and Johnson noise, as well as changes in collector cup efficiency (drift). For a 20 V 40 Ca ion-beam implemented in a three-hop, dynamic multicollection routine, the model predicts that a wide range of 48 Ca/ 43 Ca and spike/sample ratios should yield internal precisions (2s SEM ) of 0.015-0.020& for d 44/40 Ca and 0.025-0.030& for d 44/42 Ca. Using a Thermo Fisher MC-TIMS (Triton), we tested 48 Ca/ 43 Ca ¼ 1.5 [ 43 Ca/( 48 Ca + 43 Ca) ¼ 0.40 mol mol À1 ] and spike/sample ¼ 0.66 [Ca dsp /(Ca dsp + Ca smp ) ¼ 0.40 mol mol À1 ] by repeatedly analyzing OSIL Atlantic seawater, NIST SRM 915a, NIST SRM 915b, USGS BHVO-1, and CaF 2 over 4 sessions spanning 1 month. While the measured internal precisions generally agreed with model predictions, external reproducibility (2s SD ) was much worse than expected. For the 81 measurements made, the average external reproducibility was 0.223& for d 44/40 Ca and 0.126& for d 44/42 Ca. After processing raw data through the double-spike equations, nearly all fractionation-corrected ratios showed remnant fractionation patterns. Such patterns reflect deviation from ideal exponential mass-fractionation due to mixing of multiple, independently fractionating reservoirs on the filament. Additional model simulations, as well as comparison against d 44/40 Ca values determined with a 43 Ca-42 Ca double-spike, support the concept of an "average mass rule", which states that inaccuracies in fractionation-corrected data are greater for isotope ratios having an average mass further away from the average mass of the normalizing ratio. Until advancements are made to eliminate filament reservoir effects, 43 Ca-42 Ca and 46 Ca-43 Ca double-spikes should yield the most precise d 44/40 Ca and d 44/42 Ca values, respectively, when using MC-TIMS. Within the limits of the 48 Ca-43 Ca double-spike technique, we observed no evidence for 40 Ca enrichmentsamong the standards analyzed. Finally, we found that sample matrix effects do not influence the quality of Ca isotope measurements by MC-TIMS, and we tentatively propose that the external reproducibility determined from the repeated analysis of standards can represent the uncertainty of a single sample analysis.

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Technical Note: Calcium and carbon stable isotope ratios as paleodietary indicators

Cited by 34 publications

References 78 publications

Non‐traditional isotope perspectives in vertebrate palaeobiology

Non‐traditional isotope perspectives in vertebrate palaeobiology

Assessing human weaning practices with calcium isotopes in tooth enamel

Optimization of a ⁴⁸Ca–⁴³Ca double-spike MC-TIMS method for measuring Ca isotope ratios (δ^44/40Ca and δ^44/42Ca): limitations from filament reservoir mixing

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Technical Note: Calcium and carbon stable isotope ratios as paleodietary indicators

Cited by 34 publications

References 78 publications

Non‐traditional isotope perspectives in vertebrate palaeobiology

Non‐traditional isotope perspectives in vertebrate palaeobiology

Assessing human weaning practices with calcium isotopes in tooth enamel

Optimization of a 48Ca–43Ca double-spike MC-TIMS method for measuring Ca isotope ratios (δ44/40Ca and δ44/42Ca): limitations from filament reservoir mixing

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Optimization of a ⁴⁸Ca–⁴³Ca double-spike MC-TIMS method for measuring Ca isotope ratios (δ^44/40Ca and δ^44/42Ca): limitations from filament reservoir mixing