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- Ahlgren, Hans, 1984-, et al.
(författare)
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The Baltic grey seal : A 9000-year history of presence and absence
- 2022
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 32:6, s. 569-577
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Tidskriftsartikel (refereegranskat)abstract
- The grey seal (Halichoerus grypus) has been part of the Baltic Sea fauna for more than 9000 years and has ever since been subjected to extensive human hunting, particularly during the early phases of its presence in the Baltic Sea, but also in the early 20th century. In order to study their temporal genetic structure and to investigate whether there has been a genetically continuous grey seal population in the Baltic, we generated mitochondrial control region data from skeletal remains from ancient grey seals from the archaeological sites Stora Förvar (Sweden) and Neustadt (Germany) and compared these with modern grey seal data. We found that the majority of the Mesolithic grey seals represent haplotypes that is not found in contemporary grey seals, indicating that the Baltic Sea population went extinct, likely due to human overexploitation and environmental change. We hypothesize that grey seals recolonised the Baltic Sea from the North Sea. during the Bronze Age or Iron Age, and that the contemporary Baltic grey seal population is direct descendants of this recolonisation. Our study highlights the power of biomolecular archaeology to understand the factors that shape contemporary marine diversity.
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2. |
- Bro-Jørgensen, Maiken Hemme, 1990-
(författare)
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Ancient genomics of Baltic seals : Insights on the past Baltic grey seal and harp seal populations
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis aims to study and describe the ancient populations of grey and harp seals in the Baltic Sea, and to present new methodological approaches for general use in ancient DNA studies.The dissertation is comprised of five studies: a review of the use of paleogenetics in studying ancient human-marine mammal interactions; a method paper investigating patterns of DNA preservation in ancient pinniped samples; a method paper presenting a genetic sex identification method for ancient pinnipeds; a population genomic study of the Baltic grey seal; and a population genomic study of the now extinct Baltic harp seal.Guidelines for ancient DNA sample selections were deduced from broad-scale statistical modelling of factors influencing DNA preservation in pinniped bones, the most significant of which included type of bone element, collagen content, and whether the bone derive from a cave context. Modern ringed seal samples with known sex were used to test an alternative pinniped sex identification method using the annotated dog genome as a reference for quantification of the relative representation of X chromosome reads. Reliable sex identification was shown to require a minimum of 5,000 total reads mapped to the reference genome. A total of 69 mitochondrial control regions were generated for Baltic grey seals, which revealed that the Mesolithic data largely represent extinct haplotypes, the main of which continued until the Early Neolithic. A population replacement prior to the early Bronze Age introduced mitochondrial variation resembling that of modern Baltic greys seals. The level of genetic differentiation between the Baltic harp seal population and the three contemporary breeding populations, suggests that the White Sea population is the most likely ancestor of the Baltic harp seal breeding population. An increase in genetic diversity, following a hiatus with no Baltic harp seals, combined with the measures of genetic differentiation from this period, further suggests that a second colonization likely occurred from the White Sea during the early Bronze Age.
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3. |
- Bro-Jørgensen, Maiken Hemme, et al.
(författare)
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Genomic insights on the extinct Baltic harp seal population
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The harp seal is a cold adapted seal species, which requires a suitable formation of pack ice during winter and spring to secure successfully breeding. Today harp seals live in sub-Arctic regions and the North Atlantic, but during the middle Holocene Period, a breeding population existed in the Baltic Sea. In order to investigate the genetic affinity and faith of the now extinct Baltic harp seal population we analysed contemporary and ancient mitogenomes from across the species contemporary and ancient range. Ancient mitochondrial genomes were generated for a total of 49 Baltic harp seals ranging from Late Mesolithic to the Iron Age, together with five Neolithic samples from the White Sea and two Neolithic samples from the Northwest Atlantic Ocean. The ancient data was compared to published modern harp seal data assigned to the present breeding populations around Newfoundland, the Greenland Sea and the White Sea. Surprisingly only limited phylogenetic resolution was found among the ancient and modern localities. The statistical measures for genetic differentiation, however, identified significant levels of population genetic differentiation between the Baltic harp seal population and all modern populations, which suggest an independent breeding population in the Baltic Sea. The low level of genetic differentiation to the White Sea population indicate a shared ancestry between the Baltic and White Sea. The generated Skyline plot suggest second wave of colonization after a hiatus in the Baltic Sea. Interestingly, the genetic diversity in the Baltic harp seal population was significantly higher than in any of the modern populations. However, a drastic decrease in genetic diversity is observed from the Bronze Age to the Iron Age, which might be linked to effects of high hunting pressure and climatic changes towards the final extirpation of harp seals in the Baltic.
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- Glykou, Aikaterini, 1975-
(författare)
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Bjerck, Hein B., Heidi M. Breivik, Silje E. Fretheim, Ernesto L. Piana, Angélica M. Tivoli, A. Francisco J. Zangrado og Birgitte Skar (eds.) 2016: Marine Ventures: Archaeological Perspectives on Human-Sea Relations. Eqinox publishing, Sheffiels
- 2018
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Ingår i: Primitive tider. - : University of Oslo Library. - 1501-0430 .- 2535-6194. ; , s. 115-119
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Recension (övrigt vetenskapligt/konstnärligt)abstract
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6. |
- Glykou, Aikaterini, et al.
(författare)
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Intra- and inter-tooth variation in strontium isotope ratios from prehistoric seals by laser ablation multi-collector inductively coupled plasma mass spectrometry
- 2018
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Ingår i: Rapid Communications in Mass Spectrometry. - : Wiley. - 0951-4198 .- 1097-0231. ; 32, s. 1215-1224
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Tidskriftsartikel (refereegranskat)abstract
- RationaleStrontium isotope ratios (87Sr/86Sr) in modern‐day marine environments are considered to be homogeneous (~0.7092). However, in the Baltic Sea, the Sr ratios are controlled by mixing seawater and continental drainage from major rivers discharging into the Baltic. This pilot study explores if variations in Sr can be detected in marine mammals from archaeological sites in the Baltic Sea. Methods87Sr/86Sr ratios were measured in tooth enamel from three seal species by laser ablation multi‐collector inductively coupled plasma mass spectrometry (LA‐MC‐ICP‐MS). The method enables micro‐sampling of solid materials. This is the first time that the method has been applied to marine samples from archaeological collections. ResultsThe analyses showed inter‐tooth 87Sr/86Sr variation suggesting that different ratios can be detected in different regions of the Baltic Sea. Furthermore, the intra‐tooth variation suggests possible different geographic origin or seasonal movement of seals within different regions in the Baltic Sea through their lifetime. ConclusionsThe method was successfully applied to archaeological marine samples showing that: (1) the 87Sr/86Sr ratio in marine environments is not uniform, (2) 87Sr/86Sr differences might reflect differences in ecology and life history of different seal species, and (3) archaeological mobility studies based on 87Sr/86Sr ratios in humans should therefore be evaluated together with diet reconstruction.
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7. |
- Glykou, Aikaterini, 1975-
(författare)
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Late Mesolithic-Early Neolithic Sealers: a case study on the exploitation of marine resources during the Mesolithic-Neolithic transition in the south-western Baltic Sea.
- 2014
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Ingår i: Internet Archaeology. - : Council for British Archaeology. - 1363-5387. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- This article explores the economic significance of marine resources in the south-western Baltic Sea during the transition to agriculture. Faunal remains are used in order to explain subsistence patterns, including preferred prey, exploitation of specific ecozones, hunting methods and techniques, butchering and dietary patterns. Seasonality can be linked to specific economic advantages that result from natural faunal abundances and not selective hunting. The importance of marine resources remains steady during the transition to agriculture, as shown by residue analysis on ceramic vessels from the same archaeological context as well as by faunal abundance.
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8. |
- Glykou, Aikaterini, et al.
(författare)
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Reconstructing the ecological history of the extinct harp seal population of the Baltic Sea
- 2021
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 251
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Tidskriftsartikel (refereegranskat)abstract
- The harp seal (Pagophilus groenlandicus), today a subarctic species with breeding populations in the White Sea, around the Jan Mayen Islands and Newfoundland, was a common pinniped species in the Baltic Sea during the mid- and late Holocene. It is puzzling how an ice dependent species could breed in the Baltic Sea during the Holocene Thermal Maximum (HTM), and it remains unclear for how long harp seals bred in the Baltic Sea and when the population became extirpated. We combined radiocarbon dating of harp seal bones with zooarchaeological, palaeoenvironmental and stable isotope data to reconstruct the harp seal occurrence in the Baltic Sea. Our study revealed two phases of harp seal presence and verifies that the first colonization and establishment of a local breeding population occurred within the HTM. We suggest that periods with very warm summers but cold winters allowed harp seals to breed on the ice. Human pressure, salinity fluctuations with consequent changes in prey availability and competition for food resources, mainly cod, resulted in physiological stress that ultimately led to a population decline and local extirpation during the first phase. The population reappeared after a long hiatus. Final extinction of the Baltic Sea harp seal coincided with the Medieval Warm Period. Our data provide insights for the first time on the combined effects of past climatic and environmental change and human pressure on seal populations and can contribute with new knowledge on ongoing discussions concerning the impacts of such effects on current arctic seal populations.
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10. |
- Glykou, Aikaterini, et al.
(författare)
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Strontium isotope analysis in prehistoric cod otoliths by laser ablation multi-collector inductively coupled plasma mass spectrometry
- 2021
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Ingår i: Journal of Archaeological Science-Reports. - : Elsevier BV. - 2352-409X .- 2352-4103. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- Exploitation of aquatic resources, especially fishing, was a fundamental part of human subsistence during the Late Mesolithic Ertebolle culture (5400-4000/3900 cal BC) in Southern Scandinavia. In this pilot study we examine three cod otoliths from two Late Mesolithic locations in eastern Denmark to see whether local environmental conditions are reflected in the strontium ratios of the fish, to source the fish to either the Atlantic or the Baltic Sea and finally, to explore how fishing was conducted in relation to the settlements. We used laser ablation multi-collector inductively coupled plasma mass spectrometry for sequential sampling of the otoliths for strontium isotope analysis. All three otoliths yielded Sr-87/Sr-86 values that fall within the range of Baltic Sea water, thus indicating that cod caught by Mesolithic fishers in the Danish straits belonged to the Baltic Sea stock. Our results suggest that cod were not caught in waters immediately adjacent to the archaeological sites but rather came from the Kattegat. We could not detect any substantial change in habitat between juvenile and mature stages of the fishs lives. Our study shows the potential of isotopic analysis to address issues regarding the individual ecological history of fish and human fishing strategies.
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