Abstract
The heterogeneous distribution of ground ice in the Arctic is a key driver of uneven ground subsidence as permafrost thaws, significantly impacting infrastructure and surface/subsurface hydrology. These topographic and hydrological changes contribute to major uncertainties in energy and carbon fluxes and storage in a warming Arctic. This study aims to improve our understanding of the controls on ground ice and organic matter distribution within the top 3 m of permafrost in coastal polygonal tundra near Utqiagvik, Alaska. To this end, we apply a neural network approach to bulk density distributions derived from nondestructive X-ray tomography of soil cores, trained with laboratory analyses, to improve the resolution and spatial coverage of estimates of dry bulk density, ice content, and organic matter content. In addition, we use capacitively coupled geophysical imaging to map soil electrical conductivity and salinity variations. The results show that sedimentary deposits from ocean transgressions, along with subsequent ice wedge polygon geomorphological processes, jointly influence the distribution of ice content at various scales. The impact of the latter decreases with depth, whereas the influence of salinity and sedimentary history increases. Although the controls on the distribution of soil organic matter content (g/cm3) remain unclear, the pronounced heterogeneity in bulk density strongly influences its calculation from laboratory mass fraction measurements (g/g). From a methodological perspective, the interdependencies among soil components and the need for increased data coverage underscore the value of high-resolution density measurements, such as using X-ray tomography. Overall, this study emphasizes the importance of considering salinity constraints on ice content distribution in coastal permafrost regions. The results are expected to aid in the development of data products and process representations in geomorphological and ecosystem models.
| Original language | English |
|---|---|
| Pages (from-to) | 818-833 |
| Number of pages | 16 |
| Journal | Permafrost and Periglacial Processes |
| Volume | 36 |
| Issue number | 4 |
| DOIs | |
| State | Published - Oct 1 2025 |
Funding
Funding: This material is based upon work supported by Next-Generation Ecosystem Experiments (NGEE Arctic) funded by the US Department of Energy Office of Science Office of Biological and Environmental Research (award no. DE-AC02-05CH11231). We thank UIC Science for their guidance and for allowing us to conduct our research on the traditional homelands of the Iñupiat. This material is based upon work supported by Next-Generation Ecosystem Experiments (NGEE Arctic) funded by the US Department of Energy Office of Science Office of Biological and Environmental Research (award no. DE-AC02-05CH11231). We acknowledge Sharon Borglin for help with CT scanning and Alexander Kholodov, David Graham, Joel Rowland, Cathy Wilson, and Stan Wullschleger for help with field coring. We thank Mauro Guglielmin (Editor) and two anonymous reviewers for their constructive comments and suggestions that helped improve the quality of this manuscript. We thank UIC Science for their guidance and for allowing us to conduct our research on the traditional homelands of the Iñupiat. This material is based upon work supported by Next‐Generation Ecosystem Experiments (NGEE Arctic) funded by the US Department of Energy Office of Science Office of Biological and Environmental Research (award no. DE‐AC02‐05CH11231). We acknowledge Sharon Borglin for help with CT scanning and Alexander Kholodov, David Graham, Joel Rowland, Cathy Wilson, and Stan Wullschleger for help with field coring. We thank Mauro Guglielmin (Editor) and two anonymous reviewers for their constructive comments and suggestions that helped improve the quality of this manuscript.