Taphonomic Analysis Of Fish Remains From The Mink Island Site (Xmk-030): Implications For Zooarchaeological And Stable Isotopic Research

Thesis (Ph.D.) University of Alaska Fairbanks, 2013This dissertation is focused on shedding the taphonomic overprint at the Mink Island site (XMK-030) to assess temporal variability of the fish bone assemblage and to establish sample selection criteria for stable isotope (delta15N, delta13C) analysis. These retrospective data may be used to identify the causes and consequences of long-term variability in local fish assemblages when combined with modern fisheries and paleo-oceanographic data. To use these data, it is essential to account for the effects of biostratinomic and diagenic agents. Intertaxa and inter-elemental differences in bone density, shape, size, protein, and lipid content result in differing preservation and contamination potential. Without mitigating for the effects of these biostratinomic and diagenic agents, temporal changes in abundance may be skewed in favor of skeletal elements that best survive destruction. Moreover, stable isotope values may reflect differences in preservation and contamination rather than variability in ecosystem structure and function. The results of several experiments conducted to assess preservation and contamination levels of Mink Island fish bones revealed that: 1) Preservation and contamination potential are linked with completeness percentages and burial duration, but not with bone volume density; 2) Pacific cod dentaries that are intact, unburned, and free of visible contaminants are best suited for stable isotope analysis; 3) The modified Bell pretreatment method is validated for archaeological fish bones; and 4) Because color-affecting contaminants cannot be removed without heat, color-based methods are unsuitable for assessing the cooking/burning stage of archaeological fish bones. Interactions among humans and fishes at Mink Island were assessed using a four-stage resource depression and intensification model. The Mink Island occupants shifted their focus from small flatfishes during Stage I (7500-4500 cal. BP), to Pacific cod and sculpins during Stages II (4500-2800 cal. BP) and III (2800-900 cal. BP), to a mixture of taxa (sculpins, cods, herring, and salmon) during Stage IV (900-400 cal. BP). A decrease in Pacific cod fork lengths indicates that resource depression occurred during Stage II. Taxonomic proportion, evenness, salmon index, and skeletal element representation data demonstrate that salmon intensification did not occur during any stage at Mink Island

New insights into Eastern Beringian mortuary behavior: A terminal Pleistocene double infant burial at Upward Sun River

Here we report on the discovery of two infant burials dating to 11,500 calibrated years (cal) B.P. at the Upward Sun River site in central Alaska. The infants were interred in a pit feature with associated organic and lithic grave goods, including the earliest known North American hafted bifaces with decorated antler foreshafts. Skeletal and dental analyses indicate that Individual 1 died shortly after birth and Individual 2 was a late-term fetus, making these the youngest-aged late Pleistocene individuals known for the Americas and the only known prenate, offering, to our knowledge, the first opportunity to explore mortuary treatment of the youngest members of a terminal Pleistocene North American population. This burial was situated 40 cm directly below a cremated 3-y-old child previously discovered in association with a central hearth of a residential feature. The burial and cremation are contemporaneous, and differences in body orientation, treatment, and associated grave goods within a single feature and evidence for residential occupation between burial episodes indicate novel mortuary behaviors. The human remains, grave goods, and associated fauna provide rare direct data on organic technology, economy, seasonality of residential occupations, and infant/child mortality of terminal Pleistocene Beringians

A detailed life history of a Pleistocene steppe bison (Bison priscus) skeleton unearthed in Arctic Alaska

Detailed paleoecological evidence from Arctic Alaska’s past megafauna can help reconstruct paleoenvironmental conditions and can illustrate ecological adaptation to varying environments. We examined a rare, largely articulated and almost complete skeleton of a steppe bison (Bison priscus) recently unearthed in Northern Alaska. We used a multi-proxy paleoecological approach to reconstruct the past ecology of an individual representing a key ancient taxon. Radiocarbon dating of horn keratin revealed that the specimen has a finite radiocarbon age ∼46,000 ± 1000 cal yr BP, very close to the limit of radiocarbon dating. We also employed Bayesian age modeling of the mitochondrial genome, which estimated an age of ∼33,000–87,000 cal yr BP. Our taphonomic investigations show that the bison was scavenged post-mortem and infested by blowflies before burial. Stable carbon and oxygen isotope (δ13C and δ15N) analyses of sequentially sampled horn keratin reveal a seasonal cycle; furthermore, high δ15N values during its first few years of life are consistent with patterns observed in modern bison that undertook dispersal. We compared sequential analyses of tooth enamel for strontium isotope ratios (87Sr/86Sr) to a spatial model of 87Sr/86Sr values providing evidence for dispersal across the landscape. Synthesis of the paleoecological findings indicates the specimen lived during interstadial conditions. Our multi-proxy, paleoecological approach, combining light and heavy isotope ratios along with genetic information, adds to the broader understanding of ancient bison ecology during the Late Pleistocene, indicating that ancient bison adopted different degrees of paleo-mobility according to the prevailing paleoecological conditions and climate

Flow cytometry for near-patient testing in premature neonates reveals variation in platelet function: a novel approach to guide platelet transfusion.

BACKGROUND: Neonatal haemorrhaging is often co-observed with thrombocytopenia; however, no evidence of a causal relationship with low platelet count has been reported. Regardless, the administration of a platelet transfusion is often based upon this parameter. Accurate measurement of platelet function in small volumes of adult blood samples by flow cytometry is well established and we propose that the use of the same technology could provide complementary information to guide the administration of platelet transfusions in premature neonates. METHODS: In 28 neonates born at 27-41 weeks gestation, platelet function after stimulation agonists was measured using fibrinogen binding and P-selectin expression (a marker of degranulation). RESULTS: Platelets of neonates with gestation of ≤36 weeks (n = 20) showed reduced fibrinogen binding and degranulation with ADP, and reduced degranulation with CRP-XL. Degranulation Scores of 7837 ± 5548, 22,408 ± 5301 and 53,131 ± 12,102 (mean ± SEM) identified significant differences between three groups: 36 weeks gestation). Fibrinogen binding and degranulation responses to ADP were significantly reduced in suspected septic neonates (n = 6) and the Fibrinogen Binding scores clearly separated the septic and healthy group (88.2 ± 10.3 vs 38.6 ± 12.2, P = 0.03). CONCLUSIONS: Flow cytometric measurement of platelet function identified clinically different neonatal groups and may eventually contribute to assessment of neonates requiring platelet transfusion.This study was funded by the NHSBT through the Howard Ostin Fund - Dr Ghevaert will get this amended to include the core support from Wellcome and MRC to the Stem Cell Institut

Ancient Beringian paleodiets revealed through multiproxy stable isotope analyses

The earliest Native Americans have often been portrayed as either megafaunal specialists or generalist foragers, but this debate cannot be resolved by studying the faunal record alone. Stable isotope analysis directly reveals the foods consumed by individuals. We present multi-tissue isotope analyses of two Ancient Beringian infants from the Upward Sun River site (USR), Alaska (similar to 11,500 years ago). Models of fetal bone turnover combined with seasonally-sensitive taxa show that the carbon and nitrogen isotope composition of USR infant bone collagen reflects maternal diets over the summer. Using comparative faunal isotope data, we demonstrate that although terrestrial sources dominated maternal diets, salmon was also important, supported by carbon isotope analysis of essential amino acids and bone bioapatite. Tooth enamel samples indicate increased salmon use between spring and summer. Our results do not support either strictly megafaunal specialists or generalized foragers but indicate that Ancient Beringian diets were complex and seasonally structured.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]