Quantitative reconstruction of seasonality from stable isotopes in teeth

Abstract

2.2 Water, blood, and feed δ 18 O measurements. Sheep blood (300 l) and drinking water samples (100 l) were aliquoted into He-flushed exetainer tubes. The exetainers receiving water standards and samples contained 0.3% CO2 in He for standard CO2-H2O equilibrations; blood samples were allowed to outgas and equilibrate endogenous CO2. Equilibration incubations were conducted for 24 hours at 26 °C on a Thermo GasBench II,

Wintertime stress, nursing, and lead exposure in Neanderthal children

“…Our microsampling results show repeated, intra-annual seasonal δ 18 O fluctuations of >4‰ within individuals, with marked changes occurring over time scales of months. Sequential enamel δ 18 O measurements are more likely to capture the morphology and magnitude of environmental δ 18 O variation in temperate environments where seasonal δ 18 O fluctuations are large and dominated by relatively simple winter-summer regimes ( 9 ).…”

“…S1). The sheep was raised under controlled conditions in Bedford, MA, and calcein labeling provided temporal control for δ 18 O analyses at discrete locations within the enamel crown ( 9 , 13 ). The SHRIMP SI spot size was 30 μm, and measurements were spaced 500 μm apart for the first 33.5 mm of the tooth crown, with twofold sampling at 16.5 and 21.5 mm from the enamel cusp tip.…”

“…Scholars have attempted to circumvent this limitation by quantifying oxygen isotopes in the mineral component of tooth enamel, which forms incrementally in equilibrium with seasonally varying environmental oxygen ( 8 , 9 ) and allows paleoclimatic inferences ( 10 , 11 ). Yet, concerns about the timing of elemental incorporation during tooth mineralization and the fidelity of oxygen isotopes in teeth have hindered comprehensive investigations of the fossil record ( 9 , 12 , 13 ). The first concern arises from the likelihood that the process of enamel mineralization, which continues after initial enamel secretion, may overprint and/or shift the elemental signature of an individual’s ingestion history.…”

Oxygen isotopes in bioarchaeology: Principles and applications, challenges and opportunities

“…relative to the enamel root junction (ERJ) (Balasse, 2002;Balasse et al, 2002Balasse et al, , 2012bBendrey et al, 2015;Green et al, 2018;Kohn et al, 1996;Kohn, 1996Kohn, , 2004Kohn and Cerling, 2002;Zazzo et al, 2005Zazzo et al, , 2010. This impacts the recovery of isotope data from teeth, and there has been extensive discussion of methodological approaches that could mediate these effects, including alternative sampling strategies and mathematical corrections (Bendrey et al, 2015;Blumenthal et al, 2014;Green et al, 2018;Hoppe et al, 2004b;Kohn, 2004;Passey et al, 2005a;Trayler and Kohn, 2016;Zazzo et al, 2005Zazzo et al, , 2012. In bone, while serial sampling is not possible due to remodelling (see section 3.1), differences in remodelling rates in different skeletal elements and/or bone regions have been exploited to access seasonality or mobility information, along with the sampling of individual osteons (Koon and Tuross, 2013;Lamb et al, 2014;Meier-Augenstein and Fraser, 2008;Tütken et al, 2004).…”

The zooarchaeology and paleoecology of early hominin scavenging

“…4,26 The fat content of brains stays consistent during the dry season, while marrow fat content decreases considerably. 17 Seasonality in the death of carcasses consumed by hominins is at least theoretically detectable via oxygen isotope ratios in ungulate tooth enamel 119,120 and the presence of migratory birds or tortoises could also indicate seasonality in faunal accumulations. 121 11 | WHAT MAY HAVE BEEN SOME POTENTIAL BEHAVIORAL CONSEQUENCES OF EARLY HOMININ SCAVENGING?…”