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A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well
Question Can we reliably estimate grazing intensity, indicators of grazing intensity (i.e. field-layer height and shrub-cover), and vascular plant species richness in semi-natural grasslands from high spatial resolution satellite data? Location The Baltic Island of Oland (Sweden). Methods Fieldwork included the on-site description of grazed and ungrazed areas and shrub-cover within 107 semi-natura
A sediment sequence was taken from a closed, high altitude lake (informal name Olive-backed Lake) in the central mountain range of Kamchatka, in the Russian Far East. The sequence was dated by radiocarbon and tephrochronology and used for multi-proxy analyses (chironomids, pollen, diatoms). Although the evolution of Beringian climate through the Holocene is primarily driven by global forcing mecha
Holocene records of cellulose-inferred lake-water delta O-8 were produced from two lake-sediment sequences obtained in central and northern Kamchatka, Russian Far East. The sediment records share similar fluctuations in delta O-8 during the interval of ca. 5000-800 cal yr BP that correspond (inversely) with changes in K+ content of the GISP2 ice-core record from Greenland, a proxy for the relative
A radiocarbon and tephra-dated sediment core from Lifebuoy Lake, located on the north-east coast of Kamchatka Peninsula, was analysed for pollen, spores, diatoms, chironomids and tephra in order to uncover regional environmental history. The 6500-year environmental history of Lifebuoy Lake correlates with the broad regional patterns of vegetation development and climate dynamics with both diatoms
Pollen and sediment stratigraphic analyses of a transect of core sequences are used to reconstruct Holocene lake-level changes in Lake Igelsjon, southern Sweden. The pattern of changes seen in the records is related to climatic/hydrological changes and agrees principally with the pattern characteristically found in lakes in southern Sweden. However, compared with an earlier study based on isotopic
The C-14 dating method is the cornerstone for inferring age estimates for natural archives covering the last 50 000 yrs. However, C-14 age calibration for the last ice age relies mostly on records that only indirectly reflect the atmospheric C-14 concentrations. In consequence, calendar age estimates are significantly more uncertain for the period of the last ice age compared to the past 14000 yrs
Changes in the tropical hydrological cycle have been recorded world wide in speleothem records dating back more than 200,000 years for some areas. Numerous empirical and modelling studies have demonstrated a strong link between the intensity of the northern hemisphere monsoon and the precessional insolation cycle (similar to 23 ka (thousand years)). Here we present simulations of the climate condi
Against the backdrop of the ecological crisis, food production systems will need to transform to ensure future food security. There are contrasting visions of what this transformation should look like. This paper scrutinizes these competing imaginaries of future agriculture and associated styles of anticipation in Tanzania. We find that both government visions and global crop models anticipate fut
We have analyzed an almost 14,000 year old peat sequence on the island of Isla de los Estados (55 degrees S. 64 degrees W), east of Tierra del Fuego, in the core of the Southern Hemisphere Westerlies. A multitude of methods have been used: high resolution C-14 dating; detailed lithologic descriptions including humification degree; loss on ignition; magnetic susceptibility; bulk density; pollen and
We conducted an interlaboratory comparison between our radiocarbon-related research group at Lund University and the established ETH-Zurich facility to test the quality of the results obtained in Lund and to identify sources of potential background differences and scatter. We did find differences between the 2 laboratories in the contributions of chemical preparation, graphitization, and measureme
Can a climate-triggered export of old contaminants from the soil alter the lead (Pb) contaminant burden of subarctic lakes? To address this question, we reconstructed the pollution history of three high latitude lakes situated in a region where a recent climatic shift has occurred. Dated sediment records were used as archives of past Pb inputs to the lakes, where the difference in the (206)Pb/(207
A pollen diagram from a small peat bog on the island of Tristan da Cunha in the central South Atlantic (37 degrees 05'S, 12 degrees 17'W) is presented. The pollen diagram contains data from both introduced and native plant taxa. The earliest pollen grains from introduced Plantago lanceolata are dated to around AD 1570, and probably represent unintentional introductions of weeds by the earliest Por
Permafrost in peatlands of subarctic Sweden is presently thawing at accelerated rates, which raises questions about the destiny of stored carbon and nutrients and impacts on adjacent freshwater ecosystems. In this study we use peat and lake sediment records from the Stordalen palsa mire in northern Sweden to address the late Holocene (5,000 cal BP-present) development of the mire as well as relate
In this paper we present new relative sea-level data from southern Greenland, a key area for understanding the Greenland Ice Sheet (GIS) response to climate change. Within fourteen lakes and marine lagoons from the inner part of Bredefjord (Nordre Sermilik) in southern Greenland, isolations revealed by stratigraphic and palaeoecological analyses are dated and relative sea levels reconstructed. Due
Dendroclimatic investigations of subfossil Scots pine (Pinus sylvestris) from two raised bogs in southern Sweden yielded a continuous floating 1492-year long tree-ring record. By cross-dating with bog-pine chronologies from Lower Saxony, Germany, the South Swedish record was assigned an absolute age of 5219-3728 BC. The cross-match between ring-width chronologies from these two regions, separated
A Holocene sediment sequence from Lake Seukokjaure, a subarctic lake at tree-line in northern Sweden, was analyzed to assess major changes in the structure and functioning of the aquatic ecosystem in response to climate change and tree-line dynamics. The compiled multi-proxy data, including sedimentary pigments, diatoms, chironomids, pollen, biogenic silica (BSi), carbon (C), nitrogen (N) elementa
For model-based quantitative reconstructions of past vegetation cover on the scale of landscapes, pollen productivity estimates (PPEs) are key input parameters. In this study, we employed a random sampling strategy to collect moss polsters at 20 sites in Changbai Mountain, northeastern China. A detailed vegetation survey within 1000-m radius around each sampling point was carried out and digitized
A late Holocene diatom stratigraphy of Bottom Pond (37050S, 12 70W) was studied and interpreted to infer paleolimnological and climate changes on Tristan da Cunha, South Atlantic. The diatom flora of Bottom Pond is dominated by meroplanktonic Aulacoseira alpigena and A. distans and a benthic/epiphytic flora including Achnanthes spp., Naviculadicta spp., Eunotia taxa and Frustulia rhomboides. The f
Integration of palynological proxies with annual lamina counting, C-14, Pb-210, Cs-137 and Am-241 radiometric dating, historical documents and old cadastral maps enabled reconstruction of changes in the cultural landscape resulting from extensive forest clearance, arable farming and slash-and-burn practices in South Estonia over the last millennium. Changes in land-cover were quantitatively recons
