Monique Sézanne Patzner, M.Sc.
Center for Applied Geoscience (ZAG)
phone: +49 (0)7071 29 73061
I was born and grew up in Constance, Germany. I received my Bachelor degree in Geoecology from the University Tuebingen in October, 2015. During my Bachelor studies I focused on microbiology, hydrology, biogeochemistry, ecology, plant and soil science and worked mostly on the improvement of drinking water filters used widely in Vietnam and Bangladesh to remove arsenic. During a three months research stay at the Centre for Environmental Technology and Sustainable Development (CETASD), University of Science in Hanoi, I gained experienced in (1) environmental contamination (sampling of soil and water) and human exposure of polychlorinated biphyenyls (PCBs) in Hanoi, Ho Chi Minh City and Bien Hoa, Vietnam, (2) household sand filters to remove arsenic from contaminated groundwater, (3) monitoring arsenic concentrations in regions of Hanoi, (4) conducting a survey to collect more data on general consciousness of the arsenic problem. Followed by a research stay at Eawag (Swiss Federal Institute of Aquatic Science and Technology) in Zürich, Switzerland, there I performed column experiments to model SONO-filters used in Bangladesh for arsenic removal to determine the efficiency over time and to quantify the role of microbes in this household sand filters with the main focus on Mn(II)-oxidizing bacteria. The titel of my Bachelor Thesis was “The role of Mn(II)-oxidizing bacteria in household sand filters, Vietnam – Mn(IV) oxide layer, an indicator for total iron and arsenic removal?”. I continued studying at the Univeristy Tuebingen and received my Master degree in Geoecology in March, 2018. During my Master Thesis work, I focused on “Microbial arsenic mobilization in groundwater aquifers in the Red River Delta, Vietnam – A microcosm based approach.”. In April 2018, I started with my PhD in the Geomicrobiology group in Tuebingen supervised by Prof. Dr. Andreas Kappler and Prof. Dr. Thomas Borch.
The microbial iron cycling in permafrost peatland soils affected by global warming
50% of global underground carbon is estimated to be stored in permafrost soils which could be released as CO2 and CH4 gases under progressive climate change. This permafrost carbon feedback is currently considered to be the most important carbon-cycle feedback missing from climate models. Microbial production of these greenhouse gases depends on carbon mobility and bioavailability. In soils and sediments, carbon compounds strongly bind to the surfaces of rusty iron oxide minerals. Therefore, the microbial formation and dissolution of these Fe minerals highly affect carbon bioavailability and CO2/CH4 emissions. At our field site in Abisko (Sweden), a sub-Arctic peatland underlain by permafrost, our preliminary results showed high concentrations of Fe (up to 20 mg Fe/g dry soil) and organic C (up to 44% C per dry weight). Annual thawing-freezing cycles will cause either mineral formation by microbial Fe(II) oxidation (oxic conditions) or iron mineral dissolution by microbial Fe(III) reduction (anoxic conditions), strongly influencing carbon mobility and CO2/CH4 release. As under increasing temperatures permafrost thaws, raised soil regions which are dry and well oxygenated collapse and become waterlogged wetlands. This shift leads to anoxic conditions which will dramatically impact the stability of iron minerals. The work of the Geomicrobiology group in Tuebingen has already shown that iron-oxidizing and -reducing bacteria are responsible for precipitation and dissolution of iron minerals and thus carbon mobility. However, the association of carbon with Fe minerals in different stages of thawing permafrost soils has not yet been investigated in detail and the role of microorganisms in Fe cycling and carbon storage has not been evaluated and quantified in such environments. To predict future climate, it is essential to know whether temperature increase will lead to mineral formation and carbon sequestration or to the opposite effect, i.e. to mineral dissolution and greenhouse gas emissions, which could tremendously affect the climate on our whole planet thus every human being. Therefore, we want to identify (i) the association of carbon with iron minerals, (ii) the active iron cycling microbes under different stages of permafrost thawing, and (iii) how this impacts CO2/CH4 emissions using interdisciplinary techniques such as selective extractions and carbon analysis of solid, aqueous and gas phase, including FT-ICR-MS, nanoSIMS and STXM, GC-MS analysis and cultivation and quantification techniques such as MPNs, microcosms and batch experiments. This frontier research will allow us to predict the consequences of global warming on CO2/CH4 emissions from permafrost soils.
For more details about the research conducted in the Borch group please click here.