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This dataset provides detailed geochemical and soil property measurements from permafrost-affected soils across a deglaciation gradient and an unglaciated, loess-influenced site on the North Slope of Alaska. Each record includes depth-resolved information for individual samples, including Sample ID, upper, lower, and mid-depths, site, and soil type, along with mineralogical and chemical properties such as pyrophosphate-, oxalate-, and citrate-extractable Al and Fe (Al_pyro, Fe_pyro, Al_ox, Fe_ox, Al_cit, Fe_cit), calcium (Ca_pyro), total carbon and nitrogen (Percent_C, Percent_N), pH, and calculated Al–Fe indices (AlFep, AlFeo, AlFec, PC). The dataset enables analyses of organo–mineral interactions, soil organic carbon, and mineralogical controls across landscape and permafrost depth gradients, and is intended to support reproducibility and further studies of Arctic soil biogeochemistry.
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Environmental controls on observed spatial variability of soil pore water geochemistry in small headwater catchments underlain with permafrost
Abstract. Soil pore water (SPW) chemistry can vary substantially acrossmultiple scales in Arctic permafrost landscapes. The magnitude of thesevariations and their relationship to scale are critical considerations forunderstanding current controls on geochemical cycling and for predictingfuture changes. These aspects are especially important for Arctic changemodeling where accurate representation of sub-grid variability may benecessary to predict watershed-scale behaviors. Our research goal is tocharacterize intra- and inter-watershed soil water geochemical variations attwo contrasting locations in the Seward Peninsula of Alaska, USA. We thenattempt to identify the key factors controlling concentrations of importantpore water solutes in these systems. The SPW geochemistry of 18 locationsspanning two small Arctic catchments was examined for spatial variabilityand its dominant environmental controls. The primary environmental controlsconsidered were vegetation, soil moisture and/or redox condition, water–soilinteractions and hydrologic transport, and mineral solubility. The samplinglocations varied in terms of vegetation type and canopy height, presence orabsence of near-surface permafrost, soil moisture, and hillslope position.Vegetation was found to have a significant impact on SPW NO3-concentrations, associated with the localized presence of nitrogen-fixingalders and mineralization and nitrification of leaf litter from tall willowshrubs. The elevated NO3- concentrations were, however, frequentlyequipoised by increased microbial denitrification in regions with sufficientmoisture to support it. Vegetation also had an observable impact on soil-moisture-sensitive constituents, but the effect was less significant. Theredox conditions in both catchments were generally limited by Fe reduction,seemingly well-buffered by a cache of amorphous Fe hydroxides, with the mostreducing conditions found at sampling locations with the highest soilmoisture content. Non-redox-sensitive cations were affected by a widevariety of water–soil interactions that affect mineral solubility andtransport. Identification of the dominant controls on current SPWhydrogeochemistry allows for qualitative prediction of future geochemicaltrends in small Arctic catchments that are likely to experience warming andpermafrost thaw. As source areas for geochemical fluxes to the broaderArctic hydrologic system, geochemical processes occurring in theseenvironments are particularly important to understand and predict withregards to such environmental changes.
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- Award ID(s):
- 1832238
- PAR ID:
- 10507800
- Publisher / Repository:
- Cryosphere
- Date Published:
- Journal Name:
- The Cryosphere
- Volume:
- 17
- Issue:
- 9
- ISSN:
- 1994-0424
- Page Range / eLocation ID:
- 3987 to 4006
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.5194/tc-17-3987-2023
