Soil Science Society of America, Soil Science Society of America Journal, 5(77), p. 1842
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information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. R esearch on Antarctic soils is relatively recent. In Maritime Antarctica, warmer temperatures and greater water availability (Campbell and Claridge, 1987) contribute to the occurrence of different soils with distinct chemical characteristics (Michel et al., 2006; Schaefer et al., 2008; Malandrino et al., 2009) and enhanced nutrient cycling (Bokhorst et al., 2007; Pereira et al., 2013). The influence of terrestrial nesting and breeding activities of ocean-feeding birds (especially penguins) on the genesis and behavior of Antarctic soils is rela-tively well reported, and ornithogenic soils are considered the most developed soils in Antarctica (Tatur, 1989; Michel et al., 2006; Simas et al., 2006, 2007; Pereira et al., 2013). The deposition of faunal excrements and their reaction with the mineral substrate, with a great sea–land transfer of organic matter and nutrients, results in hotspots of biological activity (Heine and Speir, 1989). The pH of fresh guano is initially alkaline and decreases rapidly to values frequently <5.0 due to the forma-tion of H 2 SO 4 and HNO 3 during the biological stabilization of the guano (Tatur, 1989). Acid reactions with the mineral substrate lead to the release of lithogenic elements such as Al and Fe and the transformation of clay minerals, resulting in a deep process of phosphatization with the accumulation of crystalline and poorly crystalline secondary phosphates (Tatur, 1989; Simas et al., 2006, 2007).