| 1. |
- Jones, Samantha E., et al.
(författare)
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Lake and crannog : A 2500-year palaeoenvironmental record of continuity and change in NE Scotland
- 2022
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 285
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Tidskriftsartikel (refereegranskat)abstract
- Wetland environments have been important resources for human habitation since prehistoric times and in parts of northern Europe these have witnessed the construction of artificial islet settlements, known as ‘crannogs’ in Scotland and Ireland. This paper presents a high-resolution multi-proxy palaeoenvironmental study from the Loch of Leys, Aberdeenshire, Scotland, the site of a recently excavated crannog that provides a chronological context for its inhabitation. The combined datasets demonstrate that the first occupation from AD 20–210 coincided not only with a transitional phase from lake to wetland (mire) but also with the timing of the first major Roman campaigns in northeast Scotland. Techniques including microfossil analysis, geochemistry, IR-spectroscopy and physical properties integrated with archaeological and historical records have helped to better define both natural changes that took place in the wetland environment and human activity (agriculture, fires, metal working) spanning the Roman Iron Age through to the present. This has allowed a better understanding of the responses of existing Iron Age communities to Roman military activity (e.g. through continuity or change in land use) as well as the resources exploited in frontier zones during the Roman and post Roman eras. This has wider significance not just for Scotland but also for other parts of Europe that had similar frontiers and conflict zones during the Roman period.
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| 2. |
- Lopez-Costas, Olalla, et al.
(författare)
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Human bones tell the story of atmospheric mercury and lead exposure at the edge of Roman World
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 710
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric metal pollution is a major health concern whose roots pre-date industrialization. This study pertains the analyses of ancient human skeletons and compares them with natural archives to trace historical environmental exposure at the edge of the Roman Empire in NW Iberia The novelty of our approach relies on the combination of mercury, lead and lead isotopes. We found over a 700-year period that rural Romans incorporated two times more mercury and lead into their bones than post-Romans inhabiting the same site, independent of sex or age. Atmospheric pollution sources contributed on average 57% (peaking at 85%) of the total lead incorporated into the bones in Roman times, which decreased to 24% after the decline of Rome. These values and accompanying changes in lead isotopic composition mirror changes in atmospheric Pb deposition recorded in local peatlands. Thus, skeletons are a time-transgressive archive reflecting contaminant exposure.
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| 3. |
- Martínez Cortizas, Antonio, et al.
(författare)
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Holocene atmospheric dust deposition in NW Spain
- 2020
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 30:4, s. 507-518
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric dust plays an important role in terrestrial and marine ecosystems, particularly those that are nutrient limited. Despite that most dust originates from arid and semi-arid regions, recent research has shown that past dust events may have been involved in boosting productivity in nutrient-poor peatlands. We investigated dust deposition in a mid-latitude, raised bog, which is surrounded by a complex geology (paragneiss/schist, granite, quartzite and granodiorite). As proxies for dust fluxes, we used accumulation rates of trace (Ti, Zr, Rb, Sr and Y) as well as major (K and Ca) lithogenic elements. The oldest, largest dust deposition event occurred between similar to 8.6 and similar to 7.4 ka BP, peaking at similar to 8.1 ka BP (most probably the 8.2 ka BP event). The event had a large impact on the evolution of the mire, which subsequently transitioned from a fen into a raised bog in similar to 1500 years. From similar to 6.7 to similar to 4.0 ka BP, fluxes were very low, coeval with mid-Holocene forest stability and maximum extent. In the late Holocene, after similar to 4.0 ka BP, dust events became more prevalent with relatively major deposition at similar to 3.2-2.5, similar to 1.4 ka BP and similar to 0.35-0.05 ka BP, and minor peaks at similar to 4.0-3.7, similar to 1.7, similar to 1.10-0.95 ka BP and similar to 0.74-0.58 ka BP. Strontium fluxes display a similar pattern between similar to 11 and similar to 6.7 ka BP but then became decoupled from the other elements from the mid Holocene onwards. This seems to be a specific signal of the granodiorite batholith, which has an Sr anomaly. The reconstructed variations in dust fluxes bear a strong climatic imprint, probably related to storminess controlled by North Atlantic Oscillation conditions. Complex interactions also arise because of increased pressure from human activities.
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| 4. |
- Mighall, Tim M., et al.
(författare)
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Climate Change, Fire and Human Activity Drive Vegetation Change during the Last Eight Millennia in the Xistral Mountains of NW Iberia
- 2023
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Ingår i: Quaternary. - : MDPI AG. - 2571-550X. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- An 8500-year record of high-resolution pollen, non-pollen palynomorph, microscopic charcoal and selected geochemical data (Ti, Zr and Pb) is presented from an ombrotrophic mire from the Xistral Mountains, Galicia, North-West Iberia. The results suggest that vegetation changes over the last eight millennia are primarily the result of human disturbance, fire and climate change. Climate and fire were the main factors influencing vegetation development during the early to mid-Holocene, including a short-lived decline in forest cover c. 8.2 cal. ka BP. Changes associated with the 4.2 and 2.8 cal. Ka BP events are less well defined. Human impact on vegetation became more pronounced by the late Holocene with major periods of forest disturbance from c. 3.1 cal. ka BP onwards: during the end of Metal Ages, Roman period and culminating in the permanent decline of deciduous forests in the post-Roman period, as agriculture and metallurgy intensified, leading to the creation of a cultural landscape. Climate change appears to become less influential as human activity dominates during the Late Holocene.
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| 5. |
- Myrstener, Erik, et al.
(författare)
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Long-term development and trajectories of inferred lake-water organic carbon and pH in naturally acidic boreal lakes
- 2021
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Ingår i: Limnology and Oceanography. - : John Wiley & Sons. - 0024-3590 .- 1939-5590. ; 66:6, s. 2408-2422
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Tidskriftsartikel (refereegranskat)abstract
- Monitoring of surface waters in the boreal region over the last decades shows that waters are becoming browner. This timeframe may not, however, be sufficient to capture underlying trajectories and driving mechanisms of lake-water quality, important for prediction of future trajectories. Here we synthesize data from seven lakes in the Swedish boreal landscape, with contemporary lake-water total organic carbon (TOC) concentrations of 1.4–14.4 mg L−1, to conceptualize how natural and particularly human-driven processes at the landscape scale have regulated lake-water TOC levels over the Holocene. Sediment-inferred trends in TOC are supported by several proxies, including diatom-inferred pH. Before ~ 700 ce, all lakes were naturally acidic (pH 4.7–5.4) and the concentrations of inferred lake-water TOC were high (10–23 mg L−1). The introduction of traditional human land use from ~ 700 ce led to a decrease in lake-water TOC in all lakes (to 5–14 mg L−1), and in four poorly buffered lakes, also to an increase in pH by > 1 unit. During the 20th century, industrial acid deposition was superimposed on centuries of land use, which resulted in unprecedentedly low lake-water TOC in all lakes (3–11 mg L−1) and severely reduced pH in the four poorly buffered lakes. The other lakes resisted pH changes, likely due to close connections to peatlands. Our results indicate that an important part of the recent browning of boreal lakes is a recovery from human impacts. Furthermore, on a conceptual level we stress that contemporary environmental changes occur within the context of past, long-term disturbances.
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| 6. |
- Pearce, Elena A., et al.
(författare)
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Substantial light woodland and open vegetation characterized the temperate forest biome before Homo sapiens
- 2023
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Ingår i: Science Advances. - 2375-2548. ; 9:45
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Tidskriftsartikel (refereegranskat)abstract
- The extent of vegetation openness in past European landscapes is widely debated. In particular, the temperate forest biome has traditionally been defined as dense, closed-canopy forest; however, some argue that large herbivores maintained greater openness or even wood-pasture conditions. Here, we address this question for the Last Interglacial period (129,000–116,000 years ago), before Homo sapiens–linked megafauna declines and anthropogenic landscape transformation. We applied the vegetation reconstruction method REVEALS to 96 Last Interglacial pollen records. We found that light woodland and open vegetation represented, on average, more than 50% cover during this period. The degree of openness was highly variable and only partially linked to climatic factors, indicating the importance of natural disturbance regimes. Our results show that the temperate forest biome was historically heterogeneous rather than uniformly dense, which is consistent with the dependency of much of contemporary European biodiversity on open vegetation and light woodland.
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