Correlative Microscopy: a tool for understanding soil weathering in modern analogues of early terrestrial biospheres

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.

Downloads

Download Preprint

Authors

Ria Mitchell, Peter Davies , Paul Kenrick , Tobias Volkenandt, Cameron Pleydell-Pearce, Richard Johnston 

Abstract

Correlative imaging provides a method of investigating complex systems by combining analytical (chemistry) and imaging (tomography) information across dimensions (2D-3D) and scales (centimetres-nanometres). We studied weathering processes in a modern cryptogamic ground cover (CGC) from Iceland, containing early colonizing, and evolutionary ancient, communities of mosses, lichens, fungi, and bacteria. Targeted multi-scale X-ray Microscopy (XRM) of a grain in-situ within a soil core revealed networks of surficial and internal features (tunnels) originating from organic-rich surface holes. Further targeted 2D grain characterisation by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (SEM-EDS), following an intermediate manual correlative preparation step, revealed Fe-rich nodules within the tunnels. Finally, nanotomographic imaging by focussed ion beam microscopy (FIB-SEM) revealed coccoid and filamentous-like structures within subsurface tunnels, as well as accumulations of Fe and S in grain surface crusts, which may represent a biological rock varnish/glaze. We attribute these features to biological processes. This work highlights the advantages and novelty of the correlative imaging approach, across scales, dimensions, and modes, to investigate biological weathering processes. Further, we demonstrate correlative microscopy as a means of identifying fingerprints of biological communities, which could be used in the geologic rock record and on extra-terrestrial bodies.

DOI

https://doi.org/10.31223/X5860Z

Subjects

Biogeochemistry, Geology, Paleobiology, Plant Sciences, Research Methods in Life Sciences, Sedimentology, Soil Science

Keywords

Tomography, Microscopy, Correlative Microscopy, Plant evolution

Dates

Published: 2021-03-18 14:37

Last Updated: 2021-03-18 21:37

License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None

Data Availability (Reason not available):
Zenodo: 10.5281/zenodo.4617439

Add a Comment

You must log in to post a comment.


Comments

There are no comments or no comments have been made public for this article.