Meet the Team
Prof. Dr. Ruben Kretzschmar
Ruben Kretzschmar is a Professor of Soil Chemistry at the Department of Environmental Systems Science, ETH Zurich. He earned his Ph.D. degree in 1994 in the Department of Soil Science at North Carolina State University, Raleigh, specializing in soil chemistry and mineralogy. He was elected Associate Professor at ETH Zurich in 1999 and Full Professor in 2002. The research of his group is primarily concerned with the biogeochemical behavior and cycling of trace elements in soils and sediments. Topics of past and current research include colloid aggregation and colloid-facilitated transport in natural porous media, competitive sorption of trace metals to minerals and humic substances, speciation of trace elements using synchrotron X-ray absorption spectroscopy, and dissolution of oxide and silicate minerals in the presence of organic ligands. Currently, his group focuses on the biogeochemistry of metals and metalloids in periodically anoxic soils, such as contaminated river floodplains, irrigated rice paddies, and coastal wetlands. Ruben Kretzschmar has authored or co-authored more than 190 research articles in peer-reviewed scientific journals, several review articles and book chapters, and one of the leading German textbooks in Soil Science.
Dr. Andrew Grigg
Andrew joined the team in January 2019 as a doctoral student and continued as a post-doctoral researcher after he defended his thesis in September 2023. He first moved to ETH in 2015 to complete a masters in Environmental Science majoring in Biogeochemistry and Pollutant Dynamics. Previously he completing undergraduate studies in environmental engineering in Australia.
Andrew researches the spatial heterogeneity of minerals in non-mixed soil incubation studies, the effect of aluminium substitution on the properties of jarosite (an iron potassium hydroxysulfate mineral) and the transformation of jarosite in flooded acid sulfate soils in Thailand.
Dr. Pierre Lefebvre
Pierre is a French geochemist interested in the fate of metal contaminants in the environment. During his PhD at Sorbonne University (Paris, France), he studied the long-term fate of noncrystalline uranium phases in the soils and sediments of a lake watershed in France, by using a combination of various geochemical and mineralogical techniques including isotope geochemistry and X-ray absorption spectroscopy.
Pierre joined the IRMIDYN team in July 2022 to study the impact of iron mineral transformations on the behavior of trace elements in soils.
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Dr. Joëlle Kubeneck
Joëlle is an environmental geochemist, who completed her PhD in the Soil Chemistry Group in 2024. She holds a BSc in Environmental Sciences (University of Tübingen, Germany) and a MSc in Marine Sciences from Utrecht University, NL. While conducting her MSc research projects, Joëlle got interested in the interaction of the iron and phosphorus cycle in eutrophic coastal sediments and the legal framework addressing eutrophication in the Baltic Sea. During her PhD, Joëlle investigated how the transformation of the iron minerals vivianite and ferrihydrite influence the phosphorus cycle in tidal sediments of Northern Germany. For this, she combines lab and field studies and applies wet chemical methods (e.g sequential extractions) and spectroscopic methods (e.g. XAS and Mössbauer spectroscopy).
Dr. Sara Martinengo
Sara completed her PhD in Agricultural Sciences at the University of Turin, focusing on the investigation of the rhizospheric processes driving phosphorus dynamics in reduced paddy soils with the application of advanced techniques (e.g. 31P-NMR and synchrotron XAS). After a short-term research period at the University of Delaware (USA), she became a member of IRMIDYN project to investigate the interconnection between inorganic and organic P forms and Fe (hydr)oxides formation and during Fe(II)-catalyzed transformation and recrystallization.
Giulia Fantappiè (2019-2022)
Giulia is an earth scientist with a background in crystallography and mineralogy. Giulia's main research interests are focused on mineral structure characterization with x-ray diffraction and spectroscopic techniques and the transformation of iron minerals in dynamic biogeochemical environments at structure level. During her time in the IRMIDYN ERC project in the Soil Chemistry group, Giulia worked on the effect of sulfidation on iron hydroxides and mackinawite (iron sulfide) stability in tidal flats and salt marshes.
Dr. Katherine Rothwell (2019-2023)
Katherine is an environmental mineralogist with a background in environmental engineering. Throughout her PhD and Postdoc, she has used a combination of laboratory and field studies to follow how mineral transformation processes occur in complex biogeochemical environments and how these transformations are linked to the cycling of nutrients and contaminants.
During the IRMIDYN project, Kath is working as part of the Wadden Sea field team studying tidal flats and salt marsh environments. Kath is also a master user for Mössbauer and Raman spectroscopy.
Dr. Laurel ThomasArrigo (2019-2023)
Laurel is an environmental chemist studying biogeochemical processes in soils and sediments. Laurel’s research links (a)biotic molecular- and micro-scale processes to physical changes at the catchment-scale in the context of climate change. Laurel combines advanced spectroscopic techniques (e.g., synchrotron (µ-)XAS, XRD, and (µ-)XRF) and analytical chemistry with model laboratory- and field-based studies. Currently, Laurel is studying (iron) mineral protection of organic matter in iron-rich wetlands of Iceland.
Laurel holds a BSc in Mathematics and History from the University of Colorado (USA) and worked as an environmental consultant before obtaining her MSc in Hydrogeology at the University of Goettingen (Germany). Laurel received her PhD from ETH Soil Chemistry in 2017, and after a brief Postdoc in the Soil Chemistry Group, joined the IRMIDYN team as a Senior Researcher in 2019.
Dr. Luiza Notini (2020-2024)
Luiza Notini has been a postdoctoral research scientist at ETH Zürich and a member of the IRMIDYN project since 2020. She received her bachelor’s and master’s degree in Environmental Engineering at the UFMG (Brazil) and her Ph.D. in Civil and Environmental Engineering at the University of Iowa (USA). Luiza’s research primarily focuses on geochemistry, exploring the fate of iron oxides in soils and groundwater. Specifically, she is employing Fe stable isotopes and 57Fe Mössbauer Spectroscopy to investigate the role of coexisting minerals during Fe(II)-catalyzed transformation and recrystallization. With the IRMIDYN team, Luiza is also adapting laboratory methods for use in field sites in tidal flats in Germany, peat soils in Iceland, and paddy soils in Thailand.
Dr. Katrin Schulz (2019-2023)
Katrin is an environmental scientist, enthusiastic about soils and their chemistry. She joined the IRMIDYN team in November 2019 as a PhD candidate. In her previous work, she studied the effect of phosphate availability on mycorrhiza abundance in German forest soils and studied iodine dynamics in soils of a tropical river catchment in Costa Rica. Continuing her path in soil chemistry, in her PhD project she is aiming to understand ferrihydrite and lepidocrocite dynamics in Thai rice paddy soils. For this, she is combining studies in laboratory model systems and at our field site in North-Eastern Thailand, using isotope labels and applying wet and dry chemistry techniques, such as ICP-MS, 57Fe Mössbauer spectroscopy and X-ray diffraction.
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