Strontium isotope analyses of archaeological cremated remains - new data and perspectives.

Cremated human remains are commonly found in the archaeological records, especially in Europe during the Metal Ages and the Roman period. Due to the high temperatures reached during cremation (up to 1000°C), most biological information locked in the isotopic composition of different tissues is heavily altered or even destroyed. The recent demonstration that strontium isotope ratio (87Sr/86Sr) remain unaltered during cremation and are even very resistant to post-burial alterations (which is not the case in unburned bone), opened new possibility for palaeomobility studies of ancient populations that practice cremations as a funerary ritual. This paper summarizes strontium isotopic data produced over the last decade which is then deposited on the open-access platform IsoArcH (https://isoarch.eu/) for any interested parties to use. It is the first time isotopic data on cremated remains is introduced in this database, significantly extending its impact on the scientific community.

Incremental enamel and dentine isotopic data of faunal remains from the United Kingdom.

This paper collates previously published data from incremental isotopic studies performed on faunal remains found within the modern boundaries of the United Kingdom (UK). The dataset represents a complete collection of zooarchaeological incremental data from the UK, consisting of 1,092 data points, obtained from 152 faunal specimens from 20 archaeological sites, dating from 7960 BC to AD 1300. 59 of these values are from incrementally sampled dentine and present stable carbon and nitrogen isotope ratios (δ 13C and δ 15N). The remaining 1,053 values are from incrementally sampled enamel, and present strontium (87Sr/86Sr, n= 193), and/or stable carbon and oxygen isotope ratios (δ 13C and δ 18O, n = 860). This dataset is a convenient resource for future researchers, enabling comparisons based on faunal species, time, and geographical location. Further, the dataset acts as a mechanism for researchers to investigate the variety of incremental sampling methodologies (enamel and dentine) which have been applied to faunal remains across the United Kingdom. For ease of access, this dataset has been deposited on the open-access platform IsoArcH (https://isoarch.eu/).

Calibrating temperature reconstructions from fish otolith oxygen isotope analysis for California's critically endangered Delta Smelt.

RATIONALE: Oxygen isotope ratios (δ18 O values) of fish otoliths (ear bones) are valuable geochemical tracers of water conditions and thermal life history. Delta Smelt (Hypomesus transpacificus) are osmerid forage fish endemic to the San Francisco Estuary, California, USA, that are on the verge of extinction. These fish exhibit a complex life history that allows them to survive in a dynamic estuarine environment; however, a rapidly warming climate threatens this thermally sensitive species. Here we quantify the accuracy and precision of using δ18 O values in otoliths to reconstruct the thermal life histories of Delta Smelt. METHODS: Delta Smelt were reared for 360 days using three different water sources with different ambient δ18 Owater values (-8.75‰, -5.28‰, and -4.06‰) and different water temperatures (16.4°C, 16.7°C, 18.7°C, and 20.5°C). Samples were collected after 170 days (n = 28) and 360 days (n = 14) post-hatch. In situ δ18 O values were measured from the core of the otolith to the dorsal edge using secondary ion mass spectrometry (SIMS) to reconstruct temporally resolved thermal life histories. RESULTS: The δ18 Ootolith values for Delta Smelt varied as a linear inverse function of water temperature: 1000 ln α = 18.39 (±0.43, 1SE)(103 TK-1 ) - 34.56 (±1.49, 1SE) and δ18 Ootolith(VPDB) - δ18 Owater (VPDB) = 31.34(±0.09, 1SE) - 0.19(±0.01, 1SE) × T ° C. When the ambient δ18 Owater value is known, this species-specific temperature-dependent oxygen isotope fractionation model facilitated the accurate (0.25°C) and precise (±0.37°C, 2σ) reconstruction of the water temperature experienced by the fish. In contrast, the use of existing general fractionation equations resulted in inaccurate temperature reconstructions. CONCLUSIONS: The species-specific δ18 Ootolith fractionation equation allowed for accurate and precise reconstructions of water temperatures experienced by Delta Smelt. Characterization of ambient δ18 Owater values remains a critical next step for reconstructing thermal life histories of wild Delta Smelt. This tool will provide new insights into habitat utilization, potential thermal refugia, and resilience to future warming for this critically endangered fish.

Wintertime stress, nursing, and lead exposure in Neanderthal children.

Scholars endeavor to understand the relationship between human evolution and climate change. This is particularly germane for Neanderthals, who survived extreme Eurasian environmental variation and glaciations, mysteriously going extinct during a cool interglacial stage. Here, we integrate weekly records of climate, tooth growth, and metal exposure in two Neanderthals and one modern human from southeastern France. The Neanderthals inhabited cooler and more seasonal periods than the modern human, evincing childhood developmental stress during wintertime. In one instance, this stress may have included skeletal mobilization of elemental stores and weight loss; this individual was born in the spring and appears to have weaned 2.5 years later. Both Neanderthals were exposed to lead at least twice during the deep winter and/or early spring. This multidisciplinary approach elucidates direct relationships between ancient environments and hominin paleobiology.