A female woolly mammoth's lifetime movements end in an ancient Alaskan hunter-gatherer camp

Woolly mammoths in mainland Alaska overlapped with the region's first people for at least a millennium. However, it is unclear how mammoths used the space shared with people. Here, we use detailed isotopic analyses of a female mammoth tusk found in a 14,000-year-old archaeological site to show that she moved ~1000 kilometers from northwestern Canada to inhabit an area with the highest density of early archaeological sites in interior Alaska until her death. DNA from the tusk and other local contemporaneous archaeological mammoth remains revealed that multiple mammoth herds congregated in this region. Early Alaskans seem to have structured their settlements partly based on mammoth prevalence and made use of mammoths for raw materials and likely food.

Attenuation of Pb and Sb in shooting range soils by Fe amendments

Lead (Pb) and antimony (Sb) contamination pose a major environmental risk at firing ranges and threaten land sustainability. Methods for the stabilization of metal (loid) contaminants are necessary to prevent off-site migration of metals in surface and ground water or from soil erosion. In the present study, two remediation treatments (ferric chloride/calcium carbonate and nanoscale zero-valent iron (nZVI)) were applied to flow-through soil columns containing four types of soils (sand, sandy loam, loamy sand, and silty loam) to study Pb and Sb behavior. Water runoff was continuously monitored for three months prior to amendment addition and for the following ten months. Soils were characterized before and after reaction. We found Sb was more mobile than Pb in all soil systems and was primarily present in the dissolved fraction whereas Pb was associated with both soil organic matter (SOM) and Fe colloids. Dominant Pb solid phase species were comprised of Pb⁰, PbO, PbCO₃, and Pb sorbed to Fe(III) oxides while Sb was present as fully oxidized Sb(V) in soil and soil solution. The nZVI addition had minimal impact on Pb and Sb immobilization compared to control soil. The FeCl₂ and CaCO₃ amendment decreased pore water Sb concentrations by >80% for all soil types and >96% reduction in the fine- and coarse-grained soil types (silt loam and sand). Lead was initially mobilized coinciding with a decrease in pH from the hydrolysis of Fe(II) in solution. Additional soil treatments have the potential to be effective for system-wide immobilization with adequate additions of CaCO₃ buffer. Though this study focused on bullet fragment weathering as a source of Pb and Sb the results have application to environmental monitoring and remediation efforts at mining or industrial runoff sites.

Strontium isotopes reveal diverse life history variations, migration patterns, and habitat use for Broad Whitefish (Coregonus nasus) in Arctic, Alaska

Conservation of Arctic fish species is challenging partly due to our limited ability to track fish through time and space, which constrains our understanding of life history diversity and lifelong habitat use. Broad Whitefish (Coregonus nasus) is an important subsistence species for Alaska's Arctic Indigenous communities, yet little is known about life history diversity, migration patterns, and freshwater habitat use. Using laser ablation Sr isotope otolith microchemistry, we analyzed Colville River Broad Whitefish 87Sr/86Sr chronologies (n = 61) to reconstruct movements and habitat use across the lives of individual fish. We found evidence of at least six life history types, including three anadromous types, one semi-anadromous type, and two nonanadromous types. Anadromous life history types comprised a large proportion of individuals sampled (collectively, 59%) and most of these (59%) migrated to sea between ages 0-2 and spent varying durations at sea. The semi-anadromous life history type comprised 28% of samples and entered marine habitat as larvae. Nonanadromous life history types comprised the remainder (collectively, 13%). Otolith 87Sr/86Sr data from juvenile and adult freshwater stages suggest that habitat use changed in association with age, seasons, and life history strategies. This information on Broad Whitefish life histories and habitat use across time and space will help managers and conservation planners better understand the risks of anthropogenic impacts and help conserve this vital subsistence resource.

Lifetime mobility of an Arctic woolly mammoth

Little is known about woolly mammoth (Mammuthus primigenius) mobility and range. Here we use high temporal resolution sequential analyses of strontium isotope ratios along an entire 1.7-meter-long tusk to reconstruct the movements of an Arctic woolly mammoth that lived 17,100 years ago, during the last ice age. We use an isotope-guided random walk approach to compare the tusk's strontium and oxygen isotope profiles to isotopic maps. Our modeling reveals patterns of movement across a geographically extensive range during the animal's ~28-year life span that varied with life stages. Maintenance of this level of mobility by megafaunal species such as mammoth would have been increasingly difficult as the ice age ended and the environment changed at high latitudes.

Rapid, non-destructive analysis of calcium and strontium in eggshells by WD-XRF

We developed a simple method of analyzing the strontium (Sr) and calcium (Ca) content of intact eggshell samples in support of a broader study of how dietary Sr uptake impacts waterfowl eggshell quality. We used wavelength dispersive - x-ray fluorescence spectrometry (WD-XRF) to analyze eggshell pieces ranging in size from ∼6-mm² fragments to intact half-shells. We verified this approach on a subset of reference shells by subjecting the same region and volume of shell material from which x-ray signals were measured to analysis by inductively-coupled plasma mass spectrometry (ICP-MS). An analysis of the sources of analytical uncertainty yielded total internal error estimates of ±0.3 and 5% relative for Ca and Sr, respectively, on the basis of which the chemistry of intact shell material analyzed by WD-XRF in this study is compared. The total external errors associated with the WD-XRF results of this study in relation to certified reference material (National Institute of Standards and Technology [NIST] 1400 [a bone ash]) are ±9 and 13.5% relative for Ca and Sr, respectfully (95% CL). Our results demonstrate this method is acceptably accurate and precise for many wildlife management applications. WD-XRF analysis is a quick and inexpensive alternative to traditional methods for determining eggshell Sr and Ca that require acid digestion, allowing for generation of larger datasets that might otherwise be cost-prohibitive, while preserving sample material intact.