Südchina, insbes. die Provinz Guandong, ist eines der am dichtesten besiedelten Gebiete der Erde. Positive Konsequenz dieser Ballung ist eine äußerst dynamische Wirtschaftsentwicklung, aber gerade diese von subtropischem Monsunklima geprägte Region ist auch immer wieder Ausgangspunkt für sich schnell und zunehmend global ausbreitende epidemische Krankheiten wie zuletzt SARS. Mit der globalen Erwärmung einhergehende Klimaveränderungen könnten sich für diese Region insbesondere durch Veränderungen der Häufigkeit und Intensität tropischer Wirbelstürme, aber auch Änderungen der Niederschlagsmenge- und Intensität bemerkbar machen. Im Gegensatz zu den schon recht umfangreichen Datensätzen aus der Südchinesischen See (SCS) gibt es bisher jedoch nur sehr wenige terrestrische Paläoklimaarchive aus der Region, die Klimaveränderungen während des Holozäns, des Spätglazials oder Glazials hochauflösend dokumentieren. Wir haben deshalb einen an der nördlichen Küste der SCS gelegenen Maarsee ausgewählt, um über die Analyse von Proxydaten aus Seesedimenten solche Paläo-Klimavariationen zu untersuchen. Aus dem Sediment des Huguang-Maarsees wurden mittels Usinger-Präzisionsstechtechnik von einem Floss aus insgesamt 7 Sedimentsequenzen gewonnen, von denen die tiefste bis 57 m unter den Seeboden reicht. Die zeitliche Einstufung der Profile wurde mit Hilfe von 17 Radiokohlenstoff-Datierungen vorgenommen und ergab ein extrapoliertes Maximalalter von ca. 78.000 Jahren. Ein breites Spektrum aus sedimentologischen, geochemischen, paläo- und gesteinsmagnetischen sowie palynologischen Methoden kam sodann zum Einsatz, um die Paläo-Umweltbedingungen, die natürlich immer das entsprechende Klima widerspiegeln, während dieses Zeitraumes zu rekonstruieren. Überraschenderweise ergab sich ein von vielen bekannten Klimaprofilen der Nordhemisphäre (insbes. des Atlantikraumes, aber auch mariner Kerne aus dem Indik und Südostasien) abweichendes Muster. Im Gegensatz zu dem bekannten Grundmuster eines vergleichsweise stabilen Klimas während des Holozäns und stärkerer Schwankungen während des letzten Glazials weisen die Daten aus dem Huguang-Maarsee für das letzte Glazial im Zeitraum zwischen 15.000 und 40.000 Jahren auf relativ stabile Umweltbedingungen hin. Die älteren Bereiche zwischen 40.000 und ca. 78.000 Jahren haben durch Eintrag von umgelagertem Torf eine eher lokale Komponente und sind somit für den regionalen und globalen Vergleich ungeeignet. Das Holozän hingegen zeichnet sich durch hohe Schwankungsamplituden vieler Proxydaten (Karbonatgehalt, magnetische Suszeptibilität, organischer Kohlenstoff, Trockendichte, gesteinsmagnetische Parameter, Redox-Verhältnisse) aus, die auf ein recht variables Klima hinweisen. Besonders interessant ist die Übergangsphase vom Glazial zum Holozän, die bei etwa 15.000 Jahren vor heute in etwa zeitgleich mit dem beobachteten stärksten Meeresspiegelanstieg der Südchinesischen See einsetzt und eine abrupte Intensitätszunahme des Sommermonsuns anzeigt
Hydrothermal deposits may be created as a result of either ultramafic rock-seawater or basalt-seawater reactions. Previous studies of slow-spreading ridges indicate that in addition to basalts ultramafic rocks often make up a significant proportion of the upper oceanic crust. These ultramafic rocks are partially to completely serpentinized, indicating that reaction of hydrohtermal fluids with upper mantle lithologies is a common process. The present projekt aims to sample the serpentinized ultramafic-hosted hydrothermal systems in the Logatchev field region directly south of the Fifteen-twenty Fracture Zone at the Mid-Atlantic Ridge. The occurrence of both high- and low-temperature ultramafic-hosted systems leads to pronounced differences in the secondary mineralogy when compard to basalt-hosted hydrothermal systems. Our main aims are to study the mineralogical, geochemical and isotopic composition of bulk and clay samples to quantify the chemical changes related to serpentinization. From this we hope to better define the significance of reactions between seawater and lower crust/upper mantle in global lithosphere-seawater-exchange. To achieve these aims we will have a ship-based sampling of the Mid Atlantic Ridge between 14 degree 45'N and 15 degree 05'N using the RV Meteor from 15.1. to 13.2.2004 (M60/3).
At ANDRILL site SMS (Southern McMurdo Sound) an longer than 1000m sediment core will be drilled from a sea-ice platform covering Early/Middle Miocene (ca17 Ma) to Pleistocene strata of McMurdo Sound, Ross Sea, Antarctica. The target sediments were deposited on the western flank of the Victoria Land Basin (VLB), a structural half-graben that forms part of the West Antarctic Rift system, and experienced subsidence since late Eocene times. On this sediment core we propose to combine high-resolution on-ice measurement of chemical element concentrations using XRF core-scanner with off-ice high-precision chemical and sedimentological analysis on bulk samples (XRF, XRD, ICP-MS, biogenic components) and individual lithoclasts (LA-ICP-MS, electron microprobe, microscopy). The resulting multiple dataset will provide detailed information on sediment composition and, thus, contribute to several scientific objectives of ANDRILL such as the history of Ross/West Antarctic ice shelf expansion and retreat since ca17 million years, sea-ice presence/absence in the McMurdo region, and the history of Neogene sediment provenance and accumulation rates in the VLB. Our major goal is to improve our understanding of the Neogene paleoenvironmental evolution of Antarctica with a special focus on the Mid-Miocene climatic optimum (ca17-15 Ma) and the subsequent onset of major cooling (ca14 Ma) along with the key question on the stability of cold-polar climate conditions during the last 14 million years
Die Doktorarbeit ist Teil eines großen Forschungsprojektes (Ökologie und Diversität der Nebelwälder der Sierra de Lema), das die biotischen und abiotischen Merkmale dieser Waldökosysteme entlang eines Höhengradienten und die Veränderung dieser Merkmale im Laufe der Zeit untersucht. Die Wälder der Sierra de Lema befinden sich im Südosten Venezuelas, im Ostabschnitt des Canaima National Parks. Bestandeslücken (kleine natürliche Störungen der Wälder) verursachen Dynamik in Waldökosystemen. Die Entstehung einer Bestandeslücke erzeugt Veränderungen in den Umweltbedingungen der Wälder (Lichtversorgung, Nährstoffe, Raum), die Ressourcen werden dadurch neu verteilt. Nach der 'gap partitioning Theorie besiedeln spezialisierte Pflanzenarten die unterschiedlichen Standorte in den Bestandeslücken. Die 'Chance Hypothese besagt, dass die Verjüngungsprozesse in Bestandeslücken stochastisch sind, und von den vorherigen Umweltbedingungen (vor der Entstehung der Bestandenlücken) abhängen. Ziele dieser Dissertation sind die Beschreibung der Bestandenlückenstruktur, die Charakterisierung der Verjüngung der Bäume und Palmen, sowie die Beschreibung der Lichtversorgung und Mikrohabitatsstrukturen. Die Verjüngung der Baumarten wurde in 62 Plots in 22 Bestandeslücken aufgenommen und einige Umweltbedingungen, wie die Lichtverhältnisse, gemessen. Zusammen mit den anderen Untersuchungen in der Region, tragen die Ergebnisse dieser Doktorarbeit zu einem weiteren Verständnis der Ökosystemdynamik der Nebelwälder der Sierra de Lema und der Gran Sabana bei.
PROVESS is a joint European funded project for an interdisciplinary study of the vertical fluxes of properties through the water column and the surface and bottom boundaries based on the integrated application of new measuring techniques, new advances in turbulence theory and new models. IfM Hamburg is responsible for six tasks concerning numerical simulations of mean flow properties, turbulence and suspended matter transport. IfM's tasks in PROVESS are in detail: Physical modelling: Model development and code verification, cooperation with MUMM Management Unit of Mathemetical Models of North Sea and Scheldt Estuary), Brussels, Belgium. For this task, the existing public domain water column model GOTM (General Ocean Turbulence Model) will be extended. Model validation against existing data sets, cooperation with MUMM, Brussels, Belgium. Here some historical data sets will be simulated. These are the FLEX 1976 and the UWB Irish Sea FLY data set, both are scenarios already included into GOTM. Furthermore, the POL 1991 and North Sea data from NERC have to be simulated. Synthesis of PROVESS data with models, cooperation with close to all PROVESS partners. The northern and the southern North Sea experiments carried out during PROVESS will be simulated in detail by the numerical water column model. Modelling sediment damping of turbulence: Model development and code verification, cooperation with LHF (Laboratoire d'Hydraulique de France SA), Grenoble, France. Model validation against existing data sets, cooperation with LHF (Laboratoire d'Hydraulique de France SA), Grenoble, France. Synthesis of PROVESS data with models, cooperation with close to all PROVESS partners.
South Tirol is an important region for apple production in Europe. The mild climate allows a high productivity but during the last decades, winter damage on apple trees was observed in 3 to 4 year intervals at numerous sites in South Tirol. This winter damage in apple orchards is economically relevant as e.g. in season 2004/2005 costs of more than 6 Mio Euros were caused. There are several indications that the observed dieback of crown parts or even trees was related to frost drought. The situation is comparable to that of trees at the timberline, where winter damage was analysed in previous projects. Based on our experience with trees growing at the alpine timberline, we hypothesize that winter damage in South Tirol apple orchards is strongly influenced by the duration of water uptake blockages, the extent of transpirational water losses, the trees water storage capacity as well as the climatic conditions in autumn. We expect damage in living tissues as well as xylem embolism to cause prolonged drought stress in spring. In the proposed project, these aspects will be analysed and avoidance strategies will be developed. In field measurements at five apple orchards in South Tirol, climatic conditions and effects on tree water relations (water potential, hydraulic conductivity, water storage, transpiration) as well as winter injury will be quantified, and in experimental approaches important parameters will be analysed in detail. These data will be compared with hydraulic characteristics (vulnerability to embolism, drought resistance of living tissues, water storage capacity) of studied varieties. In consequence, numerous varieties will be screened for resistance to frost drought, whereby hydraulic as well as related anatomical parameters will be analysed to develop a valuable screening protocol for variety selection. Cultivation techniques to avoid winter damage will also be tested in thi u.s.w.
In the framework of the international ANtarctic DRILLing program (ANDRILL) the 1138 m deep core borehole SMS was drilled in the Southern McMurdo Sound (Ross Sea). The investigations of Antarctic Neogene ice sheet variations, of long-term climate evolutions and of the tectonic history of McMurdo Sound represent the main project aims. One part of the German participation in the ANDRILL project is the extensive geophysical logging of the SMS borehole. It delivers a main basis for answering a lot of questions in the scope of the whole project consisting of about 100 scientists. Interpreting the downhole logging data permits among other things to establish a complete lithological log, to characterize the drilled sediments petrophysically, to determine sedimentary structures and to get evidence about palaeoclimatic conditions during up to 19 Mio years. Seismic experiments in the borehole allow linking detailed geological information with shipborne seismic sections. This way, local results can be transformed into spatial information thus providing an important contribution to the understanding of the tectonic structure of the Ross Sea.
Tephra layers in isce cores from Antarctica help to constrain corrleations between distant deep ice cores and represent important time markers in the case they can be related to an eruption of known age. These time markers can be combined with existing chemo-stratigraphic parameters such as stratigraphy based on ä18O and äD/H. To that end, we plan to determine major and trace element compositions, grain size and morphologxy of tephra layers from the deep ice cores EPICA-Dronning Maud Land and Dome Fuji (Dronning Maud Land). This data will be used for correlations to other ice cores from Marie Byrd Land (West Antarctica), Vostok and Dome C (Wilkes Land). Such data will also allow the identification of potential source areas for the tephra, e.g.volcanic regions in Antarctica (Ross Sea Rift, Marie Bird Land, South Shetland Islands) as well as New Zealand, Patagonia and the volcanic ozean islands in the southern oceans.
In the Republic of Bashkortostan (Southern Russia) land use in general and land use practices in particular have changed due to the transformation process after the breakup of the former Soviet Union. These developments are causing land degradation and soll erosion, subsequently leading to a dramatic loss of arable land and a reduction of land productivity. The project will investigate the natural and anthropogenic causes for land degradation and soil erosion. Further more, ecological, socio-economic and political factors influencing sustainable agriculture in the region will be examined. For this study existing Russian archives, results from field work as Well as the analyses of remote sensing data will be used. Finally, guidelines and recommendations for soll conservation strategies will be developed. In addition, the existing data basis will be re-examined and adapted to international standards. The Integration of data as well as their transfer to the public will be achieved by using GIS techniques.
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