TY - JOUR A1 - Tatzel, Michael A1 - von Blanckenburg, F. A1 - Oelze, M. A1 - Bouchez, J. A1 - Hippler, D. T1 - Late Neoproterozoic seawater oxygenation by siliceous sponges JF - Nature Communications N2 - The Cambrian explosion, the rapid appearance of most animal phyla in the geological record, occurred concurrently with bottom seawater oxygenation. Whether this oxygenation Event was triggered through enhanced nutrient supply and organic carbon burial forced by increased continental weathering, or by species engaging in ecosystem engineering, remains a fundamental yet unresolved question. Here we provide evidence for several simultaneous developments that took place over the Ediacaran–Cambrian transition: expansion of siliceous sponges, decrease of the dissolved organic carbon pool, enhanced organic carbon burial, increased phosphorus removal and seawater oxygenation. This evidence is based on Silicon and carbon stable isotopes, Ge/Si ratios, REE-geochemistry and redox-sensitive elements in a chert-shale succession from the Yangtze Platform, China. According to this reconstruction, sponges have initiated seawater oxygenation by redistributing organic carbon oxidation through filtering suspended organic matter from seawater. The resulting increase in dissolved oxygen levels potentially triggered the diversification of eumetazoans. KW - Oxygenation KW - Carbon cycle KW - Silicon stable isotopes PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422339 DO - https://doi.org/10.1038/s41467-017-00586-5 SN - 2041-1723 VL - 8 SP - Article 621, 1 EP - 10 AN - OPUS4-42233 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 JF - Procedia earth and planetary science 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 DO - 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 -