Solos, geomorfologia para-periglacial e ornitogênese na Ilha Snow, Antártica Marítima

Abstract

Antarctic soil studies take place in ice-free areas. As soil properties, important information for a better understanding of the functioning of the Antarctic terrestrial ecosystems. The role of different factors of soil formation occurs with different influences, being a fundamental scalar approach. The climate, for example, acts under regional variations, altering important differences between the wetter and less cold areas (Maritime Antarctica) and drier and colder (Continental Antarctica). Other factors (parent material, organisms, relief and time) also play a fundamental role in the formation of soils, some with a strong perception of local variations. Snow Island, located in the South Shetlands Archipelago, is a poorly studied area, although it has high lithological diversity, geomorphological processes and unique landscapes, ideal for dimensioning the role of parent materials and biological activity on a local scale. The largest ice-free area on the Island is the President Head Peninsula, chosen for study in this work. The purpose of this study was to evaluate the role of lithological diversity and a selected biological activity (an influence of flying seabirds) in the relief/soil genesis and evolution. Soil morphological, physical, chemical, mineralogical and micromorphological properties were analyzed. Landforms were previously identified in satellite images (Sentinel-2), later identified and georeferenced using portable GPS. The map was produced using the ArcGIS 10.1. As a result, President Head's landform and soil map credits are shown, as well as a series of such characterizations. In general, what was identified at the local scale, the lithological diversity influences the way in which paraglacial, periglacial and coastal processes are established. President Head Peninsula can be divided into two major landscape domains: sedimentary with paraglacial processes and igneous with periglacial processes. In the periglacial sectors, pedological diversity is greater (Gelisols, Entisols and Inceptisols). Several soil properties are related to the type of rock. As it sediments clay, for example, it forms apparently more difficult soils, even in incipient degrees of weathering. Weathering occurs more homogeneously in the explosion of ideas, but some facilitate the genetics, for example, of soils with pattern ground. The role of flying birds also includes major differences in the landscape, especially in soil properties. We show that even under typical periglacial conditions in Antarctica, sites influenced by flying birds present active chemical weathering processes (phosphatization). This processes release exchangeable bases and accelerate mineralogical changes in coastal outcrops.