Although ornithogenic soils are often over 50 cm deep and sometimes may even accumulate to depths of several meters (Campbell and Claridge, 1966, Tatur, 1989, Speir and Cowling, 1984 and Emslie and Woehler, 2005), the ornithogenic soils at Edmonson Point investigated here were only ~ 20 cm deep (Emslie et al., 2007). The ornithogenic layers did not show any obvious signs of cryoturbation either within the guano horizons or between the guano and underlying mineral horizons. As suggested by Heine and Speir (1989), lack of cryoturbation in ornithogenic soils could result from lowering of freezing point by their high salt content and heat AZD1283 capacity. Adélie penguins usually establish their colonies on exposed ridge crests and mounds, which because of their higher position in the landscape become snow-free and dry, and thus available for nesting early in the summer season. Thus, aridity of penguin nesting sites may also contribute to lack of cryoturbation in ornithogenic soils. However, the lack of cryoturbation is a specific feature of the ornithogenic soils only in dry conditions of the continental Antarctic. Under the humid climate of the maritime Antarctic, intense cryoturbation and water percolation incorporates penguin guano deep into the soil profile leading to essential remodeling of underlining mineral horizons (Tatur, 1989, Tatur, 2002, Myrcha and Tatur, 1991, Tatur et al., 1997 and Michel et al., 2006).