Description: Das Projekt "FIRE-Tool: New tools in reconstructing wildfire history from sedimentary records using organic geochemical methods" wird vom Umweltbundesamt gefördert und von Universität Zürich, Geographisches Institut durchgeführt. The fire regimes of Australia, the most fire prone continent on earth, have been changing during the late Quaternary and up to the present under the influence of a changing climate and vegetation, Aboriginal impact and then by European settlers. Because fire history is an important parameter in understanding palaeoenvironmental conditions in many parts of the world, it has been reconstructed primarily by palynologists using lake cores and traditional tools (visible charcoal), combined with dating (14C, 210Pb, 137Cs) and the reconstruction of the past vegetation (pollen). Quantifying only (microscopically) visible charcoal may reflect charcoal from forest fires which are relatively large in size and structurally sound. However these techniques are less likely to quantify smaller charcoal fractions derived from grasses - probably the main contributor of charcoal in Australias vast savannas and open grassy woodlands. Therefore, we are developing a new methodology to infer past wildfires by using geochemical tools that potentially assess the whole range of fire residues in sedimentary records and that can yield additional information about the vegetation burned. In particular, we propose that a geochemical marker method (benzene polycarboxylic acids (BPCA)) would be capable to detect sedimentary fire residues that are too small to detect with standard microscopic methods. So far, however, these geochemical markers have not been used to quantify fire residues in lake sediment cores, neither have they been cross-compared to the presence of visible charcoal, which is indicative of palaeofires. The proof-of-concept study is conducted at two Australian sites where we would use molecular markers (BPCA) together with other geochemical methods to quantify past occurrences of fire and burned vegetation types. First we screen samples from about 200 depth intervals with a relatively rapid technique (MIR-PLS, mid-infrared spectroscopy with partial least square analysis) to observe major organic and inorcanic properties. Then, an in-depth, and more time-consuming characterization follows on some 20 samples from those sections of the cores, which have been identified by MIR-PLS to show significant changes in charcoal and organic carbon abundance. These sections will be analyzed using more sophisticated molecular scale techniques including the BPCA molecular marker method. (abridged text)
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Spülsaum ? Süßgräser ? Holzkohle ? Vegetation ? Waldbrand ? Seen ? Saumgesellschaft ? Organischer Kohlenstoff ? Zürich ? Benzol ? Gammaspektroskopie ? Geochemie ? Vegetationsbrand ? Seensediment ? Tracer ? Main ? Brand ? Datierung ? Gesamtkohlenstoff ? Sedimentkern ? Spektralanalyse ? Australien ? Gelöster organischer Kohlenstoff ? Wirkung ? Standardmethode ? Standortwahl ? Studie ? Technik ? Verbrennungsrückstand ? Bohrkern ? Globale Veränderung ? Globales Klima ? Feuerung ? Wald ? Probenahme ? Vegetationsgrenze ? Analyse ? Kontinent ? Kenngröße ? Mehrfachnutzung ? Pollen ? Schall ? Sonstige Begriffe ? Fire history reconstruction ? Sieb ? Werkzeug ? molecular markers ? palaeoenvironment ? sediment analyses ? Flächensanierung ? Buchgrundstück ? Kreuzung [biologisch] ?
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2010-04-01 - 2014-05-31
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