TY - JOUR A1 - Seiffert, Franz A1 - Bandow, Nicole A1 - Kalbe, Ute A1 - Milke, R. A1 - Gorbushina, Anna T1 - Laboratory tools to quantify biogenic dissolution of rocks and minerals: a model rock biofilm growing in percolation columns N2 - Sub-aerial biofilms (SAB) are ubiquitous, self-sufficient microbial ecosystems found on mineral surfaces at all altitudes and latitudes. SABs, which are the principal causes of weathering on exposed terrestrial surfaces, are characterized by patchy growth dominated by associations of algae, cyanobacteria, fungi and heterotrophic bacteria. A recently developed in vitro system to study colonization of rocks exposed to air included two key SAB participants - the rock-inhabiting ascomycete Knufia petricola (CBS 123872) and the phototrophic cyanobacterium Nostoc punctiforme ATCC29133. Both partners are genetically tractable and we used them here to study weathering of granite, K-feldspar and plagioclase. Small fragments of the various rocks or minerals (1–6 mm) were packed into flow-through columns and incubated with 0.1% glucose and 10 μM thiamine-hydrochloride (90 μL min−1) to compare weathering with and without biofilms. Dissolution of the minerals was followed by: (i) analysing the degradation products in the effluent from the columns via Inductively Coupled Plasma Spectroscopy and (ii) by studying polished sections of the incubated mineral fragments/grains using scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analyses. K. petricola/N. punctiforme stimulated release of Ca, Na, Mg and Mn. Analyses of the polished sections confirmed depletion of Ca, Na and K near the surface of the fragments. The abrupt decrease in Ca concentration observed in peripheral areas of plagioclase fragments favored a dissolution-reprecipitation mechanism. Percolation columns in combination with a model biofilm can thus be used to study weathering in closed systems. Columns can easily be filled with different minerals and biofilms, the effluent as well as grains can be collected after long-term exposure under axenic conditions and easily analyzed. KW - Biotic weathering KW - Flow-through columns KW - Plagioclase KW - K-feldspar KW - Granite PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-373395 SN - 2296-6463 VL - 4 SP - Article 31, 1 EP - 10 PB - Frontiers in Earth Science CY - Lausanne AN - OPUS4-37339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seiffert, Franz A1 - Bandow, Nicole A1 - Bouchez, J. A1 - Von Blanckenburg, F. A1 - Gorbushina, Anna T1 - Microbial colonization of bare rocks: laboratory biofilm enhances mineral weathering N2 - A laboratory biofilm consisting of the phototrophic cyanobacterium Nostoc punctiforme ATCC 29133 and the rock-inhabiting ascomycete Knufia petricola CBS 726.95 was tested for its mineral weathering potential. Minerals with different grain sizes and mineralogy were incubated with and without biofilm in batch and in flow-through column experiments. After incubation, the mineral dissolution was quantified analysing (i) leachate chemistry via ICP-OES/MS (inductively coupled plasma optical emission spectrometry/mass spectrometry) and (ii) the residual grains as thin polished sections via SEM/TEM-EDX (scanning electron microscopy/transmission electron microscopy-energy dispersive X-ray spectrometry). Mineral dissolution was enhanced in biotic experiments as compared to abiotic ones, for both batch culture and flow-through approaches. Analyses of thin polished sections confirmed the leaching of these elements near the surface of the mineral grains. These results clearly indicate a biotic effect on the weathering of minerals produced by the laboratory biofilm. KW - Biotic weathering KW - Flow-through cell KW - Albite KW - Forsterite KW - Olivine PY - 2014 U6 - https://doi.org/10.1016/j.proeps.2014.08.042 SN - 1878-5220 VL - 10 SP - 123 EP - 129 PB - Curran CY - Red Hook, NY, USA AN - OPUS4-32739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -