API src

Found 48 results.

Related terms

Monsunvariabilität in SE-China - der Huguang-Maarsee (Huguangyan)

Das Projekt "Monsunvariabilität in SE-China - der Huguang-Maarsee (Huguangyan)" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. 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

A3.3: Spatiotemporal dynamics of shallow landslides and their biotic and abiotic controls - an integrating synthesis including soil landscape modeling for determination and regionalisation of soil functional groups as well as forest modeling

Das Projekt "A3.3: Spatiotemporal dynamics of shallow landslides and their biotic and abiotic controls - an integrating synthesis including soil landscape modeling for determination and regionalisation of soil functional groups as well as forest modeling" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Department Ökologische Systemanalyse durchgeführt.

Winter damage on apple trees: causes, effects and avoidance strategies

Das Projekt "Winter damage on apple trees: causes, effects and avoidance strategies" wird vom Umweltbundesamt gefördert und von Universität Innsbruck, Institut für Botanik, Abteilung für Physiologie und Zellphysiologie Alpiner Pflanzen durchgeführt. 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.

Neogene Paleoenvironmental changes in the McMurdo Sound region: High resolution chemical and sedimentological analysis of Miocene (ca17 Ma) to Pleistocene sediments from ANDRILL Site SMS

Das Projekt "Neogene Paleoenvironmental changes in the McMurdo Sound region: High resolution chemical and sedimentological analysis of Miocene (ca17 Ma) to Pleistocene sediments from ANDRILL Site SMS" wird vom Umweltbundesamt gefördert und von Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Fachbereich Geowissenschaften durchgeführt. 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

Vegetation und Struktur der Bestandeslücken in den Nebelwäldern der Sierra de Lema, Gran Sabana, Venezuela

Das Projekt "Vegetation und Struktur der Bestandeslücken in den Nebelwäldern der Sierra de Lema, Gran Sabana, Venezuela" wird vom Umweltbundesamt gefördert und von Universität Freiburg, Waldbau-Institut durchgeführt. 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.

C1: Exploration and consolidation of silvicultural knowledge for sustainable management of forest sites in the South Ecuadorian Andes

Das Projekt "C1: Exploration and consolidation of silvicultural knowledge for sustainable management of forest sites in the South Ecuadorian Andes" wird vom Umweltbundesamt gefördert und von Technische Universität München, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Lehrstuhl für Waldbau durchgeführt. Deforestation in neotropical montane rain forests does not only lead to loss of biodiversity, but also to destruction of the socioeconomic basis for livelihood. The project aims at building-up silvicultural and ecological knowledge needed for sustainable management of different forest resources (natural and managed forests, abandoned land) in South Ecuador. The activities consider three complementary research sections: i) management of forest reproductive material of native species; ii) reforestation of different types of abandoned pastures with native species; iii) management of natural forests and potential seed sources. The investigations encompass activities on different scales ranging from seeds, individual trees, forest stands, to ecosystems. In the new phase we will deepen our integrative research in undisturbed und disturbed forest ecosystems with different degrees of degradation. New investigations will focus on clarifying the potential of direct seeding as alternative to planting for restoration of degraded ecosystems and on propagation of woody NTFP crops as supplemental utilisation option. The still existing gaps in the knowledge of the silvicultural bases for sustainable forest ecosystem management will be closed and all results will be consolidated towards regional concepts that contribute to the maintenance of the natural forest resources and its biodiversity, reduced deforestation, sustainable development of the forestry sector, and ensurance of the socio-economic needs of the people.

Physical properties, climate signals, and structural features of Tertiary sediments in the Southern McMurdo Sound (Antarctica) derived from downhole logging in the ANDRILL-SMS project

Das Projekt "Physical properties, climate signals, and structural features of Tertiary sediments in the Southern McMurdo Sound (Antarctica) derived from downhole logging in the ANDRILL-SMS project" wird vom Umweltbundesamt gefördert und von Leibniz-Institut für Angewandte Geophysik durchgeführt. 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.

Life in cold oceans:activity dependent on extracellular ion regulation?

Das Projekt "Life in cold oceans:activity dependent on extracellular ion regulation?" wird vom Umweltbundesamt gefördert und von Stiftung Alfred-Wegener-Institut für Polar- und Meeresforschung e.V. in der Helmholtz-Gemeinschaft (AWI) durchgeführt. The physiological fundamentals of temperature dependent distribution limits in cold oceans are addressed as a precondition to understand ecological performance and ecosystem function. The study will focus on the specific role of extracellular ion concentration in setting limitations to lifestyle and life history evolution. The biogeography of marine crustaceans in cold oceans is related to the combined effects of extracellular Mg2+ levels (Mg2+)e and low temperature, which act synergistically to slow muscular activity in the cold. The highly active cephalopod molluscs may have overcome the constraint of high (Mg2+)e by slightly increasing the extracellular potassium concentration ((K+)e), thereby exploiting the antagonistic effects of magnesium and potassium. We attempt to develop quantitative knowledge of the temperature dependent effects of potassium and magnesium on animal life cycle resulting from changes in physiology performance, larval development, and growth rate. In addition, it appears most crucial to understand the biochemical mechanisms leading to the increased magnesium effect in the cold. Within the crustacean phyla this work will focus on the lithodid crabs. They are suitable for such studies since they have a wide distribution range north and south of the Antarctic convergence and thus covering a broad temperature regime. For comparable studies boreal reptant crabs and boreal and Antarctic natant shrimps will also be included. Within the cephalopod phyla we will concentrate on the boreal species Sepia officinalis to investigate principle mechanisms. Accordingly, the present study is intended to explore, from a more conceptual point of view, whether limitations in ion regulation capacities and costs may play a role in setting the levels of biodiversity observed in extant Antarctic marine fauna.

Strategy and methodology for improved IWRM - An integrated interdisciplinary assessment in four twinning basins (STRIVER)

Das Projekt "Strategy and methodology for improved IWRM - An integrated interdisciplinary assessment in four twinning basins (STRIVER)" wird vom Umweltbundesamt gefördert und von Universität Bonn, Zentrum für Entwicklungsforschung durchgeführt. The ZEF research focuses on the Tungabhadra basin in south India, which is one of the four basins studied in the project. Tungabhadra river is a tributary of the Krishna river. ZEF will be mainly active in Work Package (WP) 9 IWRM in the twinned Tungabhadra and Tejo/Tagus river basins, with a focus and land and water use interactions . The research focuses on the interaction between irrigated and rainfed farming in the lower Tungabhadra basin, in the border area of the states of Karnataka and Andhra Pradesh. The districts on the Karnataka side are Raichur, Koppal and Bellary, on the Andhra Pradesh side Mahbubnagar and Kurnool. Some of the sub-themes ZEF will look at, together with other partners, are: 1) Flows and relations (people (livelihood linkages, labour), nutrients and energy, money/income, water); 2) Institutional and policy (dis)integration (departmental coordination, agency coordination, policy contradictions and alignments); 3) Innovations (water saving farming systems (SRI and other), (tiered) water users associations, water pricing and water rights, substitutability of technical and institutional solutions to water problems); 4) History (heads and tails of different kinds: the spatial dimension of social differentiation; evolution of policy regimes, natural resources degradation/conservation in historical perspective, land and water use change over time and its implications). It is part of the research design to compare the situation in the Tungabhadra basin with that in the Tajo/Tegus basin in Spain/Portugal. Other basins studied in the larger project are the Glomma basin in Norway and the Sesan basin in Vietnam/Cambodia).

SOLATERM - Promotion of a New Generation of Solar Thermal Systems in the Mediterranean Partner Countries (MPC)

Das Projekt "SOLATERM - Promotion of a New Generation of Solar Thermal Systems in the Mediterranean Partner Countries (MPC)" wird vom Umweltbundesamt gefördert und von Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH durchgeführt. The Mediterranean Partner Countries of the European Union are confronted with a rapidly increasing energy demand caused by a growing population especially in cities and increasing living standards. The region has a great potential for the use of renewable energies, notably solar energy due to its high level of solar radiation. However, only a small variety of solar thermal technologies is used in the region. The state of technology and the political support mechanisms vary strongly across the region and in relation to the EU countries, where new solar thermal applications for water and space heating as well as cooling are developed. SOLATERM is an EU-funded project that brings together research institutions, energy agencies, authorities and enterprises from EU and the Southern Mediterranean partners. The project consortium with partners from eight Southern Mediterranean and five EU countries has the aim of promoting the application of a new generation of solar thermal systems in the Mediterranean partner countries. SOLATERM combines the technological know-how of EU research institutions with the specific experiences and knowledge of the Southern Mediterranean partners. The EU partners provide important experiences in developing a successful political framework to boost the use of renewable energy.

1 2 3 4 5