J. Phys. IV France 104 (2003) 405
DOI: 10.1051/jp4:20030109

Spectromicroscopy of soil colloids

C. Schmidt¹, J. Thieme¹, U. Neuhäusler², C. Jacobsen³, B. Kaulich⁴, M. Salomé² and J. Susini<sup>2

1</sup>  Institut für Röntgenphysik, Georg-August-Universität, Geiststrasse 11, 37073 Göttingen, Germany
²  X-Ray Microscopy Beamline ID21, European Synchrotron Radiation Facility, ESRF, BP. 220, 38043 Grenoble cedex, France
³  Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794, U.S.A.
⁴  ELETTRA-Sincrotrone Trieste, X-Ray Microscopy Section, 34012 Basovizza (Trieste), Italy

Abstract
A soil with a high organic content, a calcaric phaeozem, has been imaged in a hydrated state using the Stony Brook scanning transmission X-ray microscope at the NSLS, Brookhaven, USA. This experiment has been performed at the carbon K absorption edge to determine the distribution of organic matter within this soil. Spectromicroscopic methods using the known spectra of humics are helping to distinguish between different kinds of carbon in the sample. In addition, a marsh soil from Northern Germany has been analyzed at the sulfur K-absorption edge with the scanning X-ray microscope at the ESRF (ID 21), Grenoble, France. This soil contains a variety of sulfur containing components, which are attached to the soil colloids. A major source of these components is the microbial activity. In this soil it is possible to identify spectroscopically amino acids like methionin and cysteine and proteins, which are built up from those molecules, and inorganic components like sulfates and sulfides.

© EDP Sciences 2003