Description: Our research questions are: - What are the effects of increased drought-rewetting frequencies on soil nutrient cycling and the availability of forest soil organic C? - Will total soil emissions of greenhouse gases be reduced by extended drought periods or will potential pulses during rewetting periods compensate or even outweigh this reduction, thereby leading to increased overall fluxes? - How do soil microbial communities respond to increased frequency and intensity of drying-rewetting cycles in a beech forest? The response of soil emissions of climate-relevant gases to drying and rewetting and the underlying mechanisms are still not well understood. To explain gas pulses after rewetting, a temporary increase of substrate availability has been proposed, which might occur either due to (1) dying of microorganisms during drought or rewetting, (2) release and metabolizing of osmotically active substances such as sugars during rewetting, or (3) breaking of soil aggregates which are physically protecting SOM, thereby making formerly protected substrates available to microorganisms (5, 44-46). Whereas the first two mechanisms will not alter the size of the actual substrate pool, the disruption of protective bonds and the formation of new surfaces could increase the accessibility of the available substrate, and thus increase total soil emissions of climate-relevant gases. Drought followed by rewetting as well as frost followed by thawing cause strong physical stress for soil aggregates. When dry aggregates are immersed in water, air trapped inside the aggregates is enclosed and cannot diffuse through capillary pores, which increases the internal pressure and finally disrupts the aggregates, thus making formerly occluded organic matter available for microbial decomposition.
SupportProgram
Tags: Buche ? Bodennährstoff ? Substrat ? Zucker ? Organischer Kohlenstoff ? Haftwasser ? Innenraumluft ? Osmose ? Mikrobiologie ? Wiedervernässung ? Treibhausgasemission ? Starkregen ? Bodenmikroorganismen ? Dürre ? Waldboden ? Frost ? Gasförmiger Stoff ? Treibhausgasminderung ? Bodenqualität ? Mortalität ? Wirkungsanalyse ? Wirkungsforschung ? Biologischer Abbau ? Bioverfügbarkeit ? Verwitterung ? Biologische Aktivität ? Ökosystemforschung ? Minderungspotenzial ? Bodenbildung ? Bodenprozess ? Laubwald ? Nährstoffkreislauf ? Wasserknappheit ? Klimawirkung ? Stress ? Temperaturerhöhung ? Stoffwechselaktivität ?
License: Creative Commons Namensnennung-keine Bearbeitung-Nichtkommerziell 4.0
Language: Englisch/English
Time ranges: 2014-03-01 - 2017-02-28
Webseite zum Förderprojekt
https://forschung.boku.ac.at/fis/suchen.projekt_uebersicht?sprache_in=de&menue_id_in=300&id_in=10136 (Webseite)Accessed 1 times.