A description and classification of soils and landscapes of the lower Kolyma river, northeastern Russia

Abstract

Abstract The combination of glacial history, ice‐rich parent materials, and ultra‐continental climate has produced unique soil landscapes in the Lower Kolyma River, a region representative of much of the arctic and subarctic lowlands of unglaciated western Beringia. All soils observed in the study area were underlain by permafrost. Soil development is generally controlled by available soil moisture, surface organic layer thickness, landscape position, and permafrost. The depth to the permafrost table varies from less than 25 cm under peaty surfaces to greater than one meter on rapidly drained alpine summits. The predominant parent materials for soil development in the lowlands are the “yedoma”; sediments‐Pleistocene deposits of presumed wind‐blown silt that contain large volumes of massive ground ice. Beneath the expansive taiga forest, soils exhibit active cryoturbation, as evident in disrupted soil horizons, incorporated organic matter, and hummocky surface expression. The tundra vegetation, where mean annual precipitation is less than 200 mm, tends to be dominated by forbs rather than mosses and sedges (as is common elsewhere in the Circumpolar North). National (Canadian, American, and Russian) soil classification systems varied in their ability to distinguish and effectively label unique morphologies. A newly proposed Gelisol order prepared for inclusion in the U.S. soil classification system (Soil Taxonomy) and its related taxa were quite effective in classifying a wide range of soil properties observed in the study area.