Processos pedogeomorfológicos em ambientes periglaciais: o fenômeno patterned ground na Antártica Marítima

Abstract

Patterned ground is a typical landform of periglacial environments. Physicochemical processes driven by freezing and thawing mechanisms are typical of these environments. The present study aimed to analyze soil-landform relationships and processes associated with patterned ground areas on Snow Island, Antarctica. Field descriptions, morphological, physical and chemical analyzes were carried out. Physical processes such as frost sorting and cryoclasty were identified. Marked differences were observed between the central zones and the edges of the circles of the patterned ground surfaces. Central zones present greater pedogenetic development and higher nutrient contents, while the edges present twice as much coarse fraction and greater landform stability, being more colonized by vegetation and subjected to organic matter illuviation due to the predominance of macropores between the larger grains/clasts. Different pedogenetic processes were observed between the central part, with a predominance of cryoturbation, and the edges, where podzolization occurs. This microscale variation of pedogenetic processes is very relevant for a better understanding of Antarctic ecosystems and the potential for carbon sequestration and emissions, under the present climate change scenario.