The Tuebingen Environmental Analytical Microscopy (TEAM) lab is now officially closed.

The distribution, mobility and bioavailability of toxic trace metals such as Cr, Co, Ni, Cu, Zn, As, Cd, Hg, and Pb in natural and contaminated environments are often controlled by the sorption to organic biomacromolecules and by the sorption to and co-precipitation with (bio-)minerals, in particular Fe-minerals. Chemical micro- and submicro-environments with steep geochemical gradients control speciation and stability of the involved phases.
To further our fundamental understanding of these systems, we study the influence of the submicron-size heterogeneity and chemical micro-niches of complex environmental biofilm-mineral aggregates on the speciation and partitioning of toxic trace metals. These analysis are done using synchrotron-based scanning transmission X-ray microscopy (STXM) which combines near edge X-ray absorption fine structure (NEXAFS) based speciation sensitivity with ≤ 30 nm spatial resolution
The speciation and partitioning of Ni, Cu and Zn between well-analyzed bacterial model strains, their exopolymers and associated Fe-biominerals are studied under chemically well-controlled conditions. Furthermore, metal speciation and partitioning is quantified and mapped in both pristine and anthropogenically influenced environmental systems.
Additionally we combine the high-resolution chemical mapping by STXM with electron microscopy in order to obtain structural information of our samples at high spatial resolution.
Spatially high-resolution techniques usually do not allow us for studying large sample areas that are representative for natural system such as river biofilms or lake sediments. Thus, we combine the high-resolution approaches with moderate spatial resolution microscopy. The combination with confocal laser scanning microscopy using specific fluorescence dyes and probes is used for up-scaling the STXM results and for further characterizing microbial aggregates and biofilms.

List of past research projects