279-5 Simulating Solute Transport and Carbon Dynamics in Permafrost Regions

Session: The Current Understanding of the Role of Wetland Hydrology in the Cycling of Elements and other Substances: A Technical Session in Memory of Paul H. Glaser

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Arctic and Subarctic regions are warming rapidly, accelerating permafrost thaw and altering subsurface hydrology. These changes have major implications for the mobility and reactivity  of solutes, including carbon cycling and contaminant transport. Simulating such processes requires numerical tools that couple water, energy, and solute transport under dynamic freeze-thaw and variably saturated conditions. We present SUTRA-solice, a new version of the USGS SUTRA code, developed to simulate variably saturated groundwater flow, advective-conductive heat transport with phase change, and reactive transport of multiple solute species. SUTRA-solice combines the multi-species solute transport capabilities of SUTRA-MS and the phase-change energy transport from SUTRA 4.0, with additional functionality to support temperature and saturation dependent reaction rates.

We illustrate the application of SUTRA-solice in two contexts. First, we simulate the fate and transport of dissolved organic carbon mobilized by permafrost thaw along an Arctic hillslope. The model captures key processes such as organic matter decomposition, microbial mineralization and lateral export, which depend strongly on soil temperature and moisture. These simulations help quantify the balance between vertical carbon release as greenhouse gases and lateral transport to surface waters. Second, we explore contaminant transport for a continuous permafrost setting under warming conditions. Results show that longer and deeper seasonal thaw enhances groundwater flow and increases the mobility and transformation of solutes, especially those that are weakly sorbing. Together, these examples demonstrate the flexibility of SUTRA-solice for investigating both natural and anthropogenic solute dynamics in cryohydrogeologic systems. Continued development and testing with field data will support improved understanding of hydro-biogeochemical feedbacks to climate change and inform land and water management decisions in permafrost-affected environments.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9469

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