Genesis, properties and classification of Cryosols from Admiralty Bay, maritime Antarctica

Abstract

Soils from maritime Antarctica are different than those from other Antarctic climatic zones and are among the least studied soils in Antarctica. We here present analytical and morphological data for the main soils found in Admiralty Bay, King George Island in the South Shetland Group. Fifty-six (56) pedons were described, sampled and analyzed according to standard international methods and classified according to both U.S. Soil Taxonomy and the WRB. The soils are generally weakly developed and have chemical, physical and morphological characteristics strongly influenced by the parent material. We identify four main soil groups: (i) basaltic/andesitic, (ii) acid sulfate, (iii) weakly ornithogenic and (iv) ornithogenic soils. Small adjustments are proposed for both classification systems for allowing a more adequate classification for maritime Antarctica. Greyish colored, eutric Lithic and Typic Haploturbels (Turbi–leptic Cryosols) with neutral to alkaline reaction are the most common soils in Admiralty Bay, and are usually developed from basaltic/andesitic tills. Yellowish, acid, dystric Sulphuric Haploturbels (Turbi–thionic Cryosols) are restricted to areas affected by pyritized andesites. Umbriturbels (Turbi–umbric Cryosols) only occur at sites under bird influence. Ornithogenic soils are the most developed soils in Admiralty Bay and show pronounced chemical, physical and morphological alteration of parent materials, with formation of umbric epipedons and phosphatic B horizons. Fibristels (Organo–turbic Cryosols) are restricted to hydromorphic areas under thick moss carpets.