3 research outputs found

    A study of the spatial distribution patterns of airborne polycyclic aromatic hydrocarbons in crowberry (Empetrum nigrum) in Ilulissat, Greenland

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    Polycyclic aromatic hydrocarbons (PAHs) are produced by anthropogenic activities, such as traffic and domestic heating. Due to their adverse effects to humans and natural habitats, the presence of PAHs in the environment needs to be monitored. Plants are known as natural accumulators of persistent organic pollutants (POPs) and can therefore be used for the monitoring of PAHs emitted into the environment. Contamination by PAHs also occurs in the Arctic such as Greenland due to long-range transport through air. However, as anthropogenic activities in the Arctic are increasing, there is a need to investigate the distribution of PAHs due to local emission sources. In this study, we present a systematic sampling approach to identify the influence of PAH sources in an area next to the town of Ilulissat in Greenland. Composite crowberry samples have been collected north of Ilulissat, where the town itself, an incineration site and Ilulissat airport are possible emission sources for PAHs. Matrix solid-phase extraction was used for the extraction of PAHs and the chemical analysis was performed by gas chromatography with mass spectrometry detection (GC-MS). In total, 18 out of 19 investigated PAHs could be detected in Empetrum nigrum in a concentration range of 0.69 to 93.01 μg/kgdry weight. Higher concentrations for most of the targeted PAHs were found close to the suspected emission sources and also along the road connecting them. For pyrene, the correlation between the concentration and the distance from the emission sources could be modelled and visualized using a two-dimensional exponential variogram and ordinary kriging. The range in which the samples were spatially correlated was approximately 500 m. Our results show that local emission sources contribute to the spatial distribution patterns of PAHs. Monitoring of pollution by airborne PAHs is therefore needed even in areas far from major pollution sources such as Ilulissat, Greenland. E. nigrum showed to be a feasible species for biomonitoring of PAHs due to its large abundance in the sampling area and its widespread availability in the Artic region

    Enamel proteins reveal biological sex and genetic variability within southern African Paranthropus

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    The evolutionary relationships among extinct African hominin taxa are highly debated and largely unresolved, due in part to a lack of molecular data. Even within taxa, it is not always clear, based on morphology alone, whether ranges of variation are due to sexual dimorphism versus potentially undescribed taxonomic diversity. For Paranthropus robustus , a Pleistocene hominin found only in South Africa, both phylogenetic relationships to other taxa 1,2 and the nature of intraspecific variation 3–6 are still disputed. Here we report the mass spectrometric (MS) sequencing of enamel proteomes from four ca. 2 million year (Ma) old dental specimens attributed morphologically to P. robustus, from the site of Swartkrans. The identification of AMELY-specific peptides and semi-quantitative MS data analysis enabled us to determine the biological sex of all the specimens. Our combined molecular and morphometric data also provide compelling evidence of a significant degree of variation within southern African Paranthropus , as previously suggested based on morphology alone 6 . Finally, the molecular data also confirm the taxonomic placement of Paranthropus within the hominin clade. This study demonstrates the feasibility of recovering informative Early Pleistocene hominin enamel proteins from Africa. Crucially, it also shows how the analysis of these proteins can contribute to understanding whether hominin morphological variation is due to sexual dimorphism or to taxonomic differences. We anticipate that this approach can be widely applied to geologically-comparable sites within South Africa, and possibly more broadly across the continent
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