EESS talk on "Microbial iron cycling in permafrost peatlands - Impact on organic carbon mobilisation and greenhouse gas emissions"

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Event details

Date 22.11.2022 12:1513:15  
Speaker Dr Andreas Kappler, Professor, Center for Applied Geoscience Geomicrobiology, Department of Geosciences, Eberhard-Karls-University Tuebingen, DE
Location Online
Category Conferences - Seminars
Event Language English
Abstract:
Permafrost peatlands hold enormous amounts of organic carbon, equivalent to over one-third of the carbon currently in the atmosphere (∼800 Pg). Up to 20% of the total organic carbon is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting the organic carbon from microbial degradation and transformation into greenhouse gases (GHG) such as CO2 and CH4. In this project we study how mineral iron stability and microbial processes influence mineral dissolution during permafrost thaw and determine the implications for carbon cycling and GHG emissions in a permafrost peatland in Abisko, Sweden. We found that iron mineral dissolution by fermentative and dissimilatory iron(III) reduction releases aqueous Fe2+ and aliphatic organic compounds along collapsing palsa hillslopes. Microbial community analysis and carbon emission measurements indicate that this release is accompanied by an increase in methanogen abundance and methane emissions at the collapsing front. In summary, our findings suggest that dissolution of reactive iron minerals contributes to carbon dioxide and methane production and emission, even before complete permafrost thaw.

Short biography:
Prof. Andreas Kappler studied chemistry at University of Konstanz (Germany) where he then also got his PhD in Environmental Microbiology working on iron biogeochemistry in lake sediments and organic matter transformation in soil-feeding termites. He then did a first postdoc at EAWAG (ETH Zürich) in Environmental Chemistry where he studied the interactions of redox-active natural organic matter with contaminants. His then did a second Postdoc at Caltech in Pasadena working on the role of phototrophic Fe(II) oxidation in the deposition of Banded Iron Formations. He then returned to Germany where he started his research group at University of Tuebingen. His current group has ca. 30 members and is focusing on microbial formation and transformation of (iron) minerals and the environmental implications for nutrients, contaminants and greenhouse gases.

Practical information

  • General public
  • Free
  • This event is internal

Organizer

  • EESS - IIE

Contact

  • Prof. Rizlan Bernier-Latmani, EML

Tags

Geomicrobiology iron biogeochemistry microbial iron cycling arsenic permafrost

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