Permafrost Causes Unique Fine-Scale Spatial Variability Across Tundra Soils
2021 (English)In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 35, no 3, article id e2020GB006659Article in journal (Refereed) Published
Abstract [en]
Spatial analysis in earth sciences is often based on the concept of spatial autocorrelation, expressed by W. Tobler as the first law of geography: “everything is related to everything else, but near things are more related than distant things." Here, we show that subsurface soil properties in permafrost tundra terrain exhibit tremendous spatial variability. We describe the subsurface variability of soil organic carbon (SOC) and ground ice content from the centimeter to the landscape scale in three typical tundra terrain types common across the Arctic region. At the soil pedon scale, that is, from centimeters to 1–2 m, variability is caused by cryoturbation and affected by tussocks, hummocks and nonsorted circles. At the terrain scale, from meters to tens of meters, variability is caused by different generations of ice-wedges. Variability at the landscape scale, that is, ranging hundreds of meters, is associated with geomorphic disturbances and catenary shifts. The co-occurrence and overlap of different processes and landforms creates a spatial structure unique to permafrost environments. The coefficient of variation of SOC at the pedon scale (21%–73%) exceeds that found at terrain (17%–66%) and even landscape scale (24%–67%). Such high values for spatial variation are otherwise found at regional to continental scale. Clearly, permafrost soils do not conform to Tobler's law, but are among the most variable soils on Earth. This needs to be accounted for in mapping and predictions of the permafrost carbon feedbacks through various ecosystem processes. We conclude that scale deserves special attention in permafrost regions.
Place, publisher, year, edition, pages
2021. Vol. 35, no 3, article id e2020GB006659
Keywords [en]
ground ice, permafrost, scale, soil organic carbon, tundra soils
National Category
Physical Geography
Identifiers
URN: urn:nbn:se:umu:diva-182103DOI: 10.1029/2020GB006659ISI: 000635221000010Scopus ID: 2-s2.0-85103208459OAI: oai:DiVA.org:umu-182103DiVA, id: diva2:1543837
Funder
Swedish Research CouncilEU, FP7, Seventh Framework Programme, 2827002021-04-132021-04-132023-09-05Bibliographically approved