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Beach sand deposits are widespread in the area around Sandefjord, at the western coast of the Oslofjord, southern Norway. The age of the deposits continuously increases with elevation, as the area has been subject to steady glacio-isostatic uplift throughout the Holocene. Existing local sea level curves provide age control related to elevation. Thus, the area offers excellent conditions to test hypotheses on soil formation and OSL dating. A chronosequence covering the last 10 000 years will be established. A preliminary study showed that soil formation leads to Podzols within 4300 - 6600 years. Micromorphological analyses suggest that clay illuviation takes place before and below podzolisation. It is hypothesised that clay translocation goes on contemporarily with podzolisation, but at greater soil depth, where the chemical conditions are suitable. This hypothesis will be proved by more detailed micromorphological investigation and chemical analyses. The factors controlling soil forming processes and their rates, will be determined by analyzing elemental composition, primary minerals and clay mineralogy. Preliminary OSL dating tests suggest that the beach sand deposits are OSL dateable despite the high latitude. This hypothesis will be checked by comparing OSL datings to ages derived from the 14C-based sea level curves.
This project focuses on the long-term stability (or otherwise) of vegetation, based on a series of multi-proxy records in southern South America. We will build a network of sites suitable for high-resolution reconstructions of changes in vegetation since the Last Glacial Maximum, and use these to test a null hypothesis that changes in vegetation over the past 14,000 years are driven by internal dynamics rather than external forcing factors. The extent to which the null hypothesis can be falsified will reveal the degree to which we can expect to be able to predict how vegetation is affected by external events, including future climate change. The southern fringes of the South American landmass provide a rare opportunity to examine the development of moorland vegetation with sparse tree cover in a wet, cool temperate climate of the Southern Hemisphere. We present a record of changes in vegetation over the past 17,000 years, from a lake in extreme southern Chile (Isla Santa Inés, Magallanes region, 53°38.97S; 72°25.24W; Fontana, Bennett 2012: The Holocene), where human influence on vegetation is negligible. The western archipelago of Tierra del Fuego remained treeless for most of the Lateglacial period. Nothofagus may have survived the last glacial maximum at the eastern edge of the Magellan glaciers from where it spread southwestwards and established in the region at around 10,500 cal. yr BP. Nothofagus antarctica was likely the earlier colonizing tree in the western islands, followed shortly after by Nothofagus betuloides. At 9000 cal. yr BP moorland communities expanded at the expense of Nothofagus woodland. Simultaneously, Nothofagus species shifted to dominance of the evergreen Nothofagus betuloides and the Magellanic rain forest established in the region. Rapid and drastic vegetation changes occurred at 5200 cal. yr BP, after the Mt Burney MB2 eruption, including the expansion and establishment of Pilgerodendron uviferum and the development of mixed Nothofagus-Pilgerodendron-Drimys woodland. Scattered populations of Nothofagus, as they occur today in westernmost Tierra del Fuego may be a good analogue for Nothofagus populations during the Lateglacial in eastern sites. Climate, dispersal barriers and/or fire disturbance may have played a role controlling the postglacial spread of Nothofagus. Climate change during the Lateglacial and early Holocene was a prerequisite for the expansion of Nothofagus populations and may have controlled it at many sites in Tierra del Fuego. The delayed arrival at the site, with respect to the Holocene warming, may be due to dispersal barriers and/or fire disturbance at eastern sites, reducing the size of the source populations. The retreat of Nothofagus woodland after 9000 cal. yr BP may be due to competitive interactions with bog communities. Volcanic disturbance had a positive influence on the expansion of Pilgerodendron uviferum and facilitated the development of mixed Nothofagus-Pilgerodendron-Drimys woodland.
Darstellung holozaenzeitlicher Rheinverlaeufe anhand ausgewaehlter Zeitscheiben. Es sollen klimatische und menschliche Einfluesse auf das Abflussverhalten des Rheins untersucht werden. Interdisziplinaere Zusammenarbeit mit Archaeologen und Historikern.
The present-day configuration of Indonesia and SE Asia is the results of a long history of tectonic movements, volcanisms and global eustatic sea-level changes. Not indifferent to these dynamics, fauna and flora have been evolving and dispersing following a complicate pattern of continent-sea changes to form what are today defined as Sundaland and Wallacea biogeographical regions. The modern intraannual climate of Indonesia is generally described as tropical, seasonally wet with seasonal reversals of prevailing low-level winds (Asian-Australian monsoon). However at the interannual scale a range of influences operating over varying time scales affect the local climate in respect of temporal and spatial distribution of rainfall. Vegetation generally reflects climate and to simplify it is possible to distinguish three main ecological elements in the flora of Malaysia: everwet tropical, seasonally dry tropical (monsoon) and montane. Within those major ecological groups, a wide range of specific local conditions caused a complex biogeography which has and still attract the attention of botanists and biogeographers worldwide. Being one of the richest regions in the Worlds in terms of species endemism and biodiversity, Indonesia has recently gone through intensive transformation of previously rural/natural lands for intensive agriculture (oil palm, rubber, cocoa plantations and rice fields). Climate change represents an additional stress. Projected climate changes in the region include strengthening of monsoon circulation and increase in the frequency and magnitude of extreme rainfall and drought events. The ecological consequences of these scenarios are hard to predict. Within the context of sustainable management of conservation areas and agro-landscapes, Holocene palaeoecological and palynological studies provide a valuable contribution by showing how the natural vegetation present at the location has changed as a consequence of climate variability in the long-term (e.g. the Mid-Holocene moisture maximum, the modern ENSO onset, Little Ice Age etc.). The final aim of my PhD research is to compare the Holocene history of Jambi province and Central Sulawesi. In particular: - Reconstructing past vegetation, plant diversity and climate dynamics in the two study areas Jambi (Sumatra) and Lore Lindu National Park (Sulawesi) - Comparing the ecological responses of lowland monsoon swampy rainforest (Sumatra) and everwet montane rainforests (Sulawesi) to environmental variability (vulnerability/resilience) - Investigating the history of human impact on the landscape (shifting cultivation, slash and burn, crop cultivation, rubber and palm oil plantation) - Assessing the impact and role of droughts (El Niño) and fires - Adding a historical perspective to the evaluation of current and future changes.
Recent progress in the operation of CO2 gas ion sources for accelerator mass spectrometer (AMS) 14C analysis on microgram-size samples opens a wide range of new applications in dating studies, e.g. for environmental and archeological applications. This proposal aims at implementing a gas ion source at the AMS system MICADAS at the Klaus-Tschira Laboratory of the Curt-Engelhorn-Zentrum für Archäometrie (CEZA) in Mannheim and to use this new capability for cutting-edge applications in environmental studies, namely the dating of small amounts of organic carbon contained in glacier ice and of specific organic compounds in ground water. Cold glaciers hold unique records on past climate and atmospheric composition. Mid-latitude ice cores furthermore enable reconstructions of recent ice chemistry changes, but cannot be dated by stratigraphic methods. For such ice bodies, only radiometric dating based on 14C analysis of organic matter contained in the ice matrix presently offers a reasonable dating potential in the late Holocene and beyond. The challenge of this approach lies in the very restricted availability of this matter, but the ability to analyse microgram samples of organic carbon from ice via a gas ion source should now enable reliable 14C dating of ice. Ground water constitutes an important water resource worldwide, especially in semi-arid regions, and in addition constitutes a useful climate archive. Dating of ground water by 14C in the dissolved inorganic carbon (DIC) is standard but problematic due to the complex carbonate geochemistry. Dating of ground water based on dissolved organic carbon (DOC) has been attempted with mixed success, but now the new analytical developments enable compound-specific 14C analyses of the various DOC components, offering the chance to identify compounds suitable for dating. This project is based on the extensive experience of the collaborating scientists in 14C analytics and applications as well as in the use of glacier ice and ground water as archives, including the development and application of 14C dating methods for these systems. It will establish 14C-measurements at the MICADAS AMS of the CEZA via a gas ion source on a routine base to analyse CO2-samples in the range of 5 to 40 microgram C at a precision down to 0,5 Prozent. By improving existing sample preparation techniques for glacier ice samples, reliable 14C values of the particulate and dissolved organic fractions from small (some 100 g) ice samples shall be obtained. This capability will be applied to constrain ages of cold, sedimentary glaciers as well as of small scale, cold Alpine congelation ice bodies. The project will further develop and test the tools required for micro-scale, compound-specific radiocarbon dating of ground water via its organic fraction. For this purpose, ground water samples from the Upper Rhine Graben area will be analysed, where extensive isotopic data, including DIC 14C values, are available for comparison.
As an isolated marginal sea, the Black Sea reacted particularly sensitive to paleoclimatic and paleoenvironmental changes and on both global and regional scales. In spite of its unique potential for high resolution paleoclimate reconstructions, late Quaternary sediment sequences of the Black Sea have only subordinately been studied with respect to paleoclimatic questions. This is somewhat surprising considering the key-geographic location of the Black Sea, where climate is strongly affected by two major climate systems; the North Atlantic/Siberian pressure system in winter and the Indian monsoon in summer. Highly-resolved and precisely dated paleoclimate records are crucial for reconstructing past regional climate variability, which can then be compared to paleoclimate records from the North Atlantic, Europe and the Indian monsoon domain. Several core sites in the Black Sea along the North-Anatolian rim can provide records of vegetation dynamics and changing precipitation regimes in the Anatolian hinterland as well as paleoceanographic/ paleolimnologic data of environmental changes in the marine/limnic Black Sea system itself. Uranium-series dated stalagmites from Sofular Cave located at the Black Sea coast in north-western Turkey will provide, as terrestrial counterpart, long complementary paleorecords of changes in vegetation and precipitation. When combined, such records will allow us to better quantify the far-field effects of North Atlantic climate and Indian monsoon during the Holocene, Eemian and the last two glacial/interglacial transitions (T1 and T2).
This project proposes to explore the potential of sedimentary sequences from arid Southern Levant to record past environmental and climate changes that can be compared with the evolution of human societies during the Holocene. The Levant, crucible of history, actually possesses very few archives of past climate change in its most arid parts, which restricts the possibility to compare, on a regional scale, environmental variation and the evolution of human communities through time. The region is characterised by contrasted bioclimatic conditions, from Mediterranean-type to arid. Most of the known records of environmental change are located in the moister, Mediterranean zones of the region, where increased water availability permits the presence - or the better preservation - of high-resolution and continuous archives of past climates. However, the potential of the arid environments of the Southern Levant (roughly corresponding to modern Israel, Palestine, and Jordan) to harbour records of Holocene (last ca. 11,500 years) climate change, is far from being exploited to its full extend. Following the unique discovery of Holocene organic, peat-like deposits in the rain-shadow of the Dead Sea area in Jordan, this project proposes to investigate the potential of this currently arid region to record past environmental and climate change. The organic sequences present in the mountain slopes East of the Dead Sea have been shown to contain very good pollen information. Results from a preliminary pollen study provided in particular evidence for the periodic extension of Mediterranean-type forest vegetation, from the upper Mediterranean plateaus down to the study area. These organic sequences can be further exploited to generate more precisely dated (mainly through radiocarbon techniques) and higher-resolution records of climate and environmental change for the Holocene. Pollen data will be complemented by a series of other proxies: charcoal studies indicating recurrent fires, spores and fungi revealing past grazing activities, diatom assemblages showing changes in the water quality, increased detrital content marking periods of enhanced erosion. All these results can then be integrated into dynamic models of local environmental changes and vegetation response. Furthermore, the same area contains multiple sequences of spring carbonates (tufa / travertine) waiting to be studied. The stable isotopic (oxygen and carbon) composition of spring carbonates can provide a good record of past climate change, as it registers variations in environmental factors such as temperature, parent-water composition (itself related to the source and amount of rainfall), and evaporation. The presence of carbonate sequences near organic sequences on the edge of the Dead Sea, offers an unprecedented occasion to directly compare the isotopic variations of carbonate series with environmental variations recorded in the peaty archives.
Global climate change is one of the key concerns of the 21st century, with serious implications for economies, societies and the environment. Central Asia, though rich in mineral resources, suffers from water scarcity. Since all the Central Asian countries rely heavily on irrigated agriculture, future climate change will strongly impact water availability, energy security, and sustainable development in the region. This issue needs to be urgently addressed, because any changes in the factors governing regional hydrology, or the magnitude of their impact (e.g. severity of droughts and floods) would be critical for infrastructural planning and securing food supplies in a global warming scenario. The project CADY (Central Asian Climate Dynamics) aims to reconstruct the Holocene climate variability and regional hydrology in the Central Asia along two W-E transects sandwiching the Tibetan Plateau and one N-S transect cutting across the Plateau. We will use a multiarchive, multiproxy approach and additionally focus on selected time slices (e.g. early Holocene warm period, the Medieval Warm Period, the Little ice age etc). Palaeoclimate simulations of different duration and on selected time slices will be carried out using the generated data. The combination of proxy data and model simulations will lead to an improved understanding of the physical mechanisms controlling the monsoon dynamics.
Die südecuadorianischen Anden beherbergen eine außergewöhnlich hohe Artenvielfalt. Viele verschiedene Umweltfaktoren beeinflussen sich auf sehr limitiertem Raum und erschaffen so einzigartige und komplexe Ökosysteme. Dieses Gebiet ist jedoch auf Grund des zunehmenden menschlichen Einflusses durch die fortschreitende Intensivierung der Landnutzung und des globalen Wandels hochgefährdet. Wir wissen nur wenig über die paläoökologische Geschichte und Landschaftsdynamik dieses Gebiets. Die Information über das warum und wie einer Veränderung von Ökosystemen ist unerlässlich für die Entwicklung innovativer Strategien für Naturschutz und im Hinblick auf zukünftige Klimaveränderungen. In der vorliegenden Studie werden palynologische Analysen aus den südecuadorianischen Anden vorgestellt, die dazu beitragen, Muster und Prozesse heutiger und vergangener Ökosysteme zu beleuchten. Eine paläoökologische Studie des Quimsacocha-Vulkanbeckens auf der östlichen Erhebung der Westkordillere der südecuadorianischen Anden deckt Klima-, Vegetations- und Brandregimeveränderungen in dieser Region seit dem frühen Holozän auf. Das mittlere Holozän war eine Zeit starker Umweltveränderungen, verursacht durch ein trockenes und wohl wärmeres Klima. Während des späten Holozäns wechselten sich mehrere Kalt-und Warmphasen ab. Brände können seit dem frühen Holozän im Gebiet verzeichnet werden. Sie könnten ein erstes Zeichen menschlichen Einflusses darstellen. Mit anderen paläoökologischen Aufzeichnungen aus den südecuadorianischen Anden verglichene multivariate Analysen decken teilweise konstrastierende Entwicklungen an den verschieden Standorten auf, die vermutlich durch die Heterogenität der Umweltfaktoren zu erklären sind. Weiterhin wurden Studien zum Verhältnis von heutigem Pollenregen mit der Vegetation in der Podocarpus Nationalpark-Region durchgeführt, um die Pollenverbreitungsmuster innerhalb der verschiedenen Vegetationstypen, prämontaner Wald, unterer Bergwald, oberer Bergwald und Páramo, zu verstehen und damit eine bessere Grundlage zur Interpretation fossiler Pollendaten zu schaffen. Ein Vergleich von Abundanz und An-/Abwesenheitsdaten von Familien als taxonomischer Einheit für Pollen- und Vegetation zeigt, dass Diversität, Verbreitung und Häufigkeiten beider Datensätze gut miteinander in Verbindung gebracht werden können. Dennoch werden die Muster durch variierende Anteile von durch Ferntransport eingetragenen Pollenkörnern sowie durch unterschiedliche Pollenproduktivität verschiedener Taxa und heterogene Windsysteme beeinflusst. Analysen der Pollenakkumulationsraten, die über drei Jahre erfasst wurden, lassen auf eine geringe inter-annuelle aber hohe räumliche Variation in den Daten schließen. (Text gekürzt)
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