TY - JOUR

T1 - 4D Surface Reconstructions to Study Microscale Structures and Functions in Soil Biogeochemistry

AU - Ost, Alexander D

AU - Wu, Tianyi

AU - Höschen, Carmen

AU - Mueller, Carsten W

AU - Wirtz, Tom

AU - Audinot, Jean-Nicolas

PY - 2021/7/6

Y1 - 2021/7/6

N2 - The development of high-resolution microscopy and spectroscopy techniques has allowed the analysis of microscopic 3D objects in fields like nanotechnology and life and soil sciences. Soils have the ability to incorporate and store large amounts of organic carbon. To study this organic matter (OM) sequestration, it is essential to analyze its association with soil minerals at the relevant microaggregate scale. This has been previously studied in 2D. However, 3D surface representations would allow a variable angle and magnification analysis, providing detailed insight on their architecture. Here we illustrate a 4D surface reconstruction workflow able to locate preferential sites for OM deposition with respect to microaggregate topography. We used Helium Ion Microscopy to acquire overlapping Secondary Electron (SE) images to reconstruct the soil topography in 3D. Then we used nanoscale Secondary Ion Mass Spectrometry imaging to chemically differentiate between the OM and mineral constituents forming the microaggregates. This image was projected onto the 3D SE model to create a 4D surface reconstruction. Our results show that organo-mineral associations mainly form at medium curvatures while flat and highly curved surfaces are avoided. This method presents an important step forward to survey the 3D physical structure and chemical composition of microscale biogeochemical systems correlatively.

AB - The development of high-resolution microscopy and spectroscopy techniques has allowed the analysis of microscopic 3D objects in fields like nanotechnology and life and soil sciences. Soils have the ability to incorporate and store large amounts of organic carbon. To study this organic matter (OM) sequestration, it is essential to analyze its association with soil minerals at the relevant microaggregate scale. This has been previously studied in 2D. However, 3D surface representations would allow a variable angle and magnification analysis, providing detailed insight on their architecture. Here we illustrate a 4D surface reconstruction workflow able to locate preferential sites for OM deposition with respect to microaggregate topography. We used Helium Ion Microscopy to acquire overlapping Secondary Electron (SE) images to reconstruct the soil topography in 3D. Then we used nanoscale Secondary Ion Mass Spectrometry imaging to chemically differentiate between the OM and mineral constituents forming the microaggregates. This image was projected onto the 3D SE model to create a 4D surface reconstruction. Our results show that organo-mineral associations mainly form at medium curvatures while flat and highly curved surfaces are avoided. This method presents an important step forward to survey the 3D physical structure and chemical composition of microscale biogeochemical systems correlatively.

KW - Carbon

KW - Minerals

KW - Soil

KW - Spectrum Analysis

KW - NanoSIMS

KW - Soil organic carbon

KW - mineral-associated organic matter

KW - microaggregates

KW - soil carbon cycling

U2 - 10.1021/acs.est.1c02971

DO - 10.1021/acs.est.1c02971

M3 - Journal article

C2 - 34165287

VL - 55

SP - 9384

EP - 9393

JO - Environmental Science & Technology

JF - Environmental Science & Technology

SN - 0013-936X

IS - 13

ER -