Supraglacial Soils and Soil-Like Bodies: Diversity, Genesis, Functioning (Review)

Abstract

In the 21st century, glaciers are percepted as a distinct biome that has taken on special significance in today’s world of retreating ice. Here we review the results of recent studies of organomineral formations on glaciers, their diversity, processes, functioning and the role in the biosphere. The question is raised about the possibility of involving supraglacial organomineral formations in the range of objects of soil science. We review the supraglacial zone as an area of soils and soil-like bodies, which biogeochemical processes affect the glacial biome and its surrounding landscapes. Interpretation of supraglacial organomineral formations from a soil scientist point of view revealed the following processes: accumulation and stabilization of organic matter (OM), its heterotrophic transformation, formation of dark-colored humified OM and accumulation of residual solid-phase products of functioning in situ, fine earth aggregation, and biochemical weathering. Among supraglacial formations, we distinguish pre-soils and soil-like bodies in ice and snow, metastable soil-like bodies on cryoconite and soils with microprofiles under moss communities on ice, as well as relatively stable soils with macroprofiles on fine-earth-detrital deposits with underlying glaciers and dead ice. Labile water-soluble OM, accumulated and transformed in supraglacial soils and soil-like bodies, has a significant impact on the periglacial zone, leading to the reservoir and priming effects. The studies of supraglacial organomineral systems are of fundamental importance for understanding the evolution of ecosystems on Earth as well as for modeling supraglacial formations of extraterrestrial bodies with a vast cryosphere. Supraglacial soil formation is also a model object for studying common soils under conditions of a constant external input of organic and mineral components, which contribution outside the glaciers is no less significant, but is masked by the polymineral substrate of soils and parent rocks.