Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology

Uno, Kevin T.; Quade, Jay; Fisher, Daniel C.; Wittemyer, George; Douglas‐Hamilton, Iain; Andanje, Samuel A.; Omondi, Patrick; Litoroh, M.; Cerling, Thure E.

doi:10.1073/pnas.1302226110

Cited by 68 publications

(50 citation statements)

References 39 publications

(65 reference statements)

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“…Prior work on 14 C dating of ivory has used the atmospheric 14 C/ 12 C historical record to determine the calibrated age of samples. Both Vogel et al (23) and Uno et al (25) note that the 14 C/ 12 C atmospheric record gives ivory ages that are, in general, 0-2 y earlier than the known age of the sample. This age mismatch likely results from several processes: (i) differing 14 C/ 12 C ratios between the NH and SH compounded by the lack of atmospheric 14 CO 2 measurements in the mixing zone between the hemispheres (i.e., equatorial Africa), (ii) the remobilization of nonstructural carbon during plant growth, (iii) the time lag between C fixation by plants and ingestion of plants by an elephant, and (iv) recycling of proteins in mammals.…”

Section: Resultsmentioning

confidence: 99%

“…S3). Uno et al (25) measured longitudinal growth rates of ca. 5 cm/y for two female African elephants, which correspond to radial growth rates of about 5 mm/ y based on a longitudinal/radial growth rate ratio of about 10:1.…”

Section: Resultsmentioning

confidence: 99%

“…Atmospheric 14 C (as 14 CO 2 ) enters the terrestrial biosphere by photosynthesis; 14 C is subsequently incorporated into herbivore tissues as the animals ingest plants for food. The bomb- 14 C signal has been used in human forensic studies (17)(18)(19)(20)(21) and has also been used previously to date ivory and other animal tissues including hair, horn, and tooth enamel (22)(23)(24)(25). Prior work on 14 C dating of ivory has used the atmospheric 14 C/ 12 C historical record to determine the calibrated age of samples.…”

Section: Resultsmentioning

confidence: 99%

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Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

Cerling

Barnette

Chesson

et al. 2016

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

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Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≥0.5 ton) made between 2002 and 2014 show that most ivory (ca. 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little “old” ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of “rapid” transit than ivory originating in the Tridom region of Cameroon–Gabon–Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

Cerling

Barnette

Chesson

et al. 2016

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

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“…Some applications use the presence of elevated Δ 14 C in a sample to distinguish its origin to be subsequent to 1950, whereas other applications use the rapid changes in Δ 14 CO 2 after 1963 (the socalled "bomb curve") to distinguish the year of origin of a sample more precisely. These techniques have been used to test vintages of wine and whisky, identify the age of human remains, and detect illegal ivory trading (23)(24)(25). As with radiocarbon dating, forthcoming Δ 14 CO 2 changes are likely to introduce ambiguity into these techniques, and the presence of elevated Δ 14 CO 2 will not identify samples with recent origins beyond ∼2030.…”

Section: Discussionmentioning

confidence: 99%

Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century

Graven

2015

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

127

149

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Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon (14C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio 14C/C in atmospheric CO2 (Δ14CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ14CO2 because fossil fuels have lost all 14C from radioactive decay. Simulations of Δ14CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ14CO2 near the preindustrial level of 0‰ through 2100, whereas “business-as-usual” emissions will reduce Δ14CO2 to −250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial “aging” of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

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“…The extension rates of these mastodon teeth are lower than those of African elephants (14-16 mm/yr) (Uno et al, 2013) or Columbian mammoths (estimated at 13 to 23 mm/yr by Metcalfe (2011, and Metcalfe and Longstaffe (2012)), and at 32.3 -62.5 μm/day (or 12-23 mm/yr) by Dirks et al (2012). Slower growth for mastodons than mammoths or elephants supports the hypothesis of Dirks et al (2012) that lower crowned teeth tend to have lower extension rates, both among species and within individuals.…”

Section: Growth Rates and Sampling Resolutionmentioning

confidence: 85%

Environmental change and seasonal behavior of mastodons in the Great Lakes region inferred from stable isotope analysis

Metcalfe¹,

Longstaffe²

2014

Quat. res.

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We investigate seasonal variations in the diet and drinking water of four Great Lakes mastodon (Mammut americanum) specimens using stable isotope analysis of serially sampled inner-enamel bioapatite structural carbonate (δ 13 C sc , δ 18 O sc ), and previously published bulk analyses. Isotopic analyses and thin section measurements showed that mastodon tooth enamel extension rates (~12-4 mm/yr, decreasing toward the cervix) were lower than those of mammoths or modern elephants. Mastodons had distinct and highly regular seasonal variations in δ 13 C sc and δ 18 O sc , which we interpret in the context of local glacial history and vegetation changes. Seasonal variations in δ 18 O were large but variations in δ 13 C were small, and may have been obscured if coarser sampling methods than our inner-enamel sampling approach were used. Thus, our approach may be particularly useful for understanding relatively small seasonal changes in δ 13 C within C 3 environments. The seasonal patterns, though not entirely conclusive, suggest that the Ontario mastodons did not migrate over very long distances. Rather, the climate and seasonal dietary patterns of mastodons within the region changed over time, from 12,400 to 10,400 14 C yr BP (~15,000 -12,000 cal yr BP). Insights gained using these methods can contribute to a better understanding of megafaunal extinctions and Paleoamerican lifeways.

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Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology

Cited by 68 publications

References 39 publications

Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century

Environmental change and seasonal behavior of mastodons in the Great Lakes region inferred from stable isotope analysis

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