Speaker: Professor Lenny Winkel from ETH Zurich, Switerland

Title: "New insights into the global biogeochemical cycle of selenium."

Abstract: Selenium (Se) is an important micronutrient as it is present in selenocysteine, which is referred to as the 21st amino acid. Selenocysteine is incorporated in selenoproteins that serve a wide range of biological functions. However, selenium only has a narrow range of safe dietary intake levels for humans: too low dietary intakes can lead to deficiency and too high intakes to toxicity. Generally, selenium concentrations in the environment are low and it has been estimated that up to 1 billion people around the globe have low dietary selenium intakes. Understanding selenium cycling in the environment is complex as selenium is a redox sensitive element that can occur in various chemical forms in environmental compartments (e.g., soils, waters, biota and atmosphere). Since the environmental distribution and chemical speciation of selenium is closely related to environmental health issues, it is of major importance to better understand the factors that control its distribution and biogeochemical cycling, from the molecular to global scale. Climate plays a key role in global selenium cycling, firstly by controlling soil properties and thus selenium retention in soils and secondly, the atmosphere itself is an important reservoir of selenium and thus a potential source of selenium to terrestrial ecosystems and agricultural soils. Climatic processes and atmospheric cycling may thus affect selenium status of soils and ultimately of food crops. However, the effect of climate on terrestrial selenium distributions as well as atmospheric cycling of selenium and deposition to the surface are still largely unknown. This talk will give new insights in the atmospheric sources and sinks of selenium and will show how atmospheric chemistry-climate modelling can identify patterns of atmospheric selenium deposition globally. Furthermore, it will be shown how data mining techniques and climatic and soil data can be used to establish global geospatial predictions of selenium contents in soils, which will help in the prevention of future health hazards related to changing levels of selenium in soils. ​

​Short Bio: Lenny Winkel is Associate Professor of Inorganic Environmental Geochemistry at ETH Zurich and group leader at Eawag, the Swiss Federal Institute of Aquatic Science and Technology. She did her undergraduate studies in Geology at Utrecht University in the Netherlands and obtained her Ph.D. in Geochemistry in 2006 from ETH Zurich. Dr. Winkel then did her postdoctoral research at Eawag as well as at the University of Grenoble (France), University of Aberdeen (UK) and the Technical University of Crete (Greece) in the frame of an EU-funded research project. Her postdoctoral research focused on broad-scale predictions of arsenic in groundwater and environmental transformations of trace element species. In 2011, she was awarded a Swiss National Science Foundation (SNSF) Professorship for her project investigating the global biogeochemical cycle of selenium. Her current research is aimed at understanding the processes controlling the biogeochemical cycling and environmental distribution of trace elements, and the effects of climate and environmental changes on these processes, through modelling, field and laboratory studies. A further focal point is the development of novel analytical methods to quantitatively and qualitatively analyze trace elements in different environmental matrices.