Das Projekt "Establishment and exploration of a gas ion source for micro-scale radiocarbon dating of glaciers and groundwater" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. 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.
Das Projekt "'CADY' Central Asian Climate Dynamics" wird vom Umweltbundesamt gefördert und von Universität Berlin, Institut für Meteorologie WE03, Fachrichtung Wechselwirkung im Klimasystem der Erde, Arbeitsgruppe Modellierung des Klimasystems durchgeführt. 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.
Das Projekt "SINCOS: Sinking Coasts - Geosphere, Ecosphere and Anthroposphere of the Holocene Southern Baltic Sea - Part 1.4: Changing sea levels and (semi)terrestrial landscape development in the Baltic Sea coastral area, with special attention to the role of the Darss Sill" wird vom Umweltbundesamt gefördert und von Ernst-Moritz-Arndt-Universität Greifswald, Institut für Botanik und Landschaftsökologie, Lehrstuhl für Landschaftsökologie und Ökosystemdynamik durchgeführt. The research unit SINCOS, established by the Deutsche Forschungsgemeinschaft, has been started in September 2002. The general target is the development of a model of the relation between geo-system, eco-system, climate and socio-economic system for sinking coasts of tideless seas to be developed as an example for the southern Baltic Sea since the Atlantikum. Geoscientists (geologists, geomorphologists, geodesists), biologists (palaeobotanists, palaezoologists), climate researchers and archaeologists will collaborate in order to investigate the cause and effect relation between driving forces (climatic and geological processes) and the response of the natural and social environment in the coastal areas of a transgressive sea. The reconstruction of the Litorina transgression west and east of the Darss sill structure plays the central role. Seven projects under the roof of SINCOS will deal with the acquisition and interpretation of proxy-data in order to reconstruct the history of the southwestern Baltic Sea since 8.000 calendar years BC. In the frame of two projects data will be integrated and models will be developed that mirror the processes of interrelation of different spheres to be investigated. Depending on the varying degree of quantification between measurable variables and qualitative observations models will differ between statistical data exploration and deterministic differential equations. A 4D GIS plays the central role in modelling and data integration. Results will be presented as time-dependent regionalizations of geo-, eco-, and socio-economical parameters. Simulations of future relative sea level change scenarios based on models developed are planned.
Das Projekt "Monsoonal variations and climate change during the late Holocene derived from tree rings and glacier fluctuations" wird vom Umweltbundesamt gefördert und von Universität Erlangen-Nürnberg, Institut für Geographie durchgeführt.
Das Projekt "Beach sand deposits on the coast of southern Norway as a natural experimental setup to test hypotheses on soil development and luminescence dating" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Bodenkunde und Standortslehre durchgeführt. 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.
Das Projekt "Late-Glacial and Holocene vegetational stability of southern South America" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung für Palynologie und Klimadynamik durchgeführt. 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.
Das Projekt "Holozaene Klimaschwankungen und ihr Einfluss auf die Entwicklung von Moorrandboeden im Raum Berlin" wird vom Umweltbundesamt gefördert und von Technische Universität Berlin, Fachbereich 07 Umwelt und Gesellschaft, Institut für Ökologie und Biologie, Fachgebiet Bodenkunde durchgeführt. Ziel der Arbeit ist es, die natuerliche chronologische Veraenderung von verschiedenen Mooroekosystemen und ihrer Bodenrandbereiche im Laufe des Holozaens zu rekonstruieren. Dazu werden folgende Untersuchungen durchgefuehrt: - Untersuchung des biostratigraphischen Aufbaus der Moore; - Modellierung der hydrologischen Zustaende und Wasserhaushaltskomponenten der verschiedenen Klimaphasen und - Bilanzierung der Gehalte an Carbonat, Fe, Mn und Huminstoffen, um das Ausmass des Grundwassereinflusses unter den verschiedenen Klimaphasen in Abhaengigkeit von der Moortrophie zu erfassen.
Das Projekt "Holocene dynamics of tropical rainforest, climate, fire, human impact and land use in Sulawesi and Sumatra, Indonesia" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung für Palynologie und Klimadynamik durchgeführt. 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.
Das Projekt "Hangsedimente, Boeden und Moore des Bayerischen Waldes als Zeugen des klimabedingten Landschaftswandels im Uebergang vom Spaetglazial zum Holozaen" wird vom Umweltbundesamt gefördert und von Universität Regensburg, Institut für Geographie, Arbeitsgruppe Landschaftsökologie und Bodenkunde durchgeführt. Die Studie ist Teil des DFG-Schwerpunktprogramms 'Wandel der Geo-Biosphaere waehrend der letzten 15.000 Jahre. Kontinentale Sedimente als Ausdruck sich wandelnder Klimabedingungen'. Dieses ist eingebunden in das 'Internationale Geosphaeren- und Biosphaerenprogramm (IGBP)'. Das eigene Forschungsprojekt ist interdisziplinaer angelegt und vereint geomorphologisch-bodenkundliche Untersuchungen mit vegetationsgeschichtlichen Fragestellungen auf palynologischer Grundlage. Es fokussiert vor allem auf die klimageschichtlich sensible Zeitscheibe des Uebergangs vom Spaetglazial ins Holozaen, die aus der Sicht des mitteleuropaeischen Naturraumes mit katastrophalen Entwicklungen in enger zeitlicher Abfolge einherging.
Das Projekt "Pleistozaene Sandbewegungen und zyklische Wuestenausbreitung der mediterranen Kuestenebene von Israel" wird vom Umweltbundesamt gefördert und von Universität Köln, Geologisches Institut, Abteilung Quartärgeologie durchgeführt. The East Mediterranean Coastal Plain is composed mainly of alternating sands, soils and gravel of Pleistocene-Holocene age, indicating the alternation of marine, coastal and continental environments. Archaeological/geological surveys previously conducted on the coastal plain by the principal investigators, show that until modern times the sand layers had always been empty of human occupation. Archaeological remains are found only in the paleosols which have formed between successive episodes of sand accumulation. From a human geography point of view, then, in periods of sand accumulation the coastal plain turned into a virtual desert. An attempt will be made to interpret past desertification processes by assessing actual processes of sand transportation and accumulation on the Israeli Coast. For the first time reliable chronological framework will be obtained by means of systematic application of improved method of absolute dating. This project will bring both geological and archaeological evidence in close interaction so as to elucidate the impact of adverse natural events on human subsistence and survival from prehistoric times. Present-day pattern of sand migration and distribution of grain size, shape and mineralogy along the Mediterranean coast of Israel will be examined. Present-day sand pattern will be compared with past sand along 10 east-west geotraverses across the coastal plain. A more reliable chronological framework for sand accumulation and periods of soil formation will be developed by the application of systematic luminescence dating using a combination of OSL and TL techniques. The chronological information attained will then be used to correlate the terrestrial evidence with the ocean core record (deep sea and Mediterranean record).
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