Properties, formation, and geo-ecological significance of organic soils inthe coastal region of East Antarctica (Wilkes Land)

The ice-free antarctic vegetation eases are characterized by specific soil patterns. Four organic soils from mosses in Wilkes Land close to the Austra lian Casey Station (latitude: 66 degrees 18'S, longitude: 110 degrees 32'E) are discussed with respect to soil formation, ecology, and distribution. A soil survey of the ice-free coastal landscape suggests that mosses are the main source of organic soils. The soil organic matter transformation pathw ays differ greatly despite the fact that carbon sources are mostly the same moss species. Humification rate is probably controlled by microclimatic an d soil moisture regimes as well as by the microbial colonization, which inf luences the nitrogen dynamics. The soils are affected by mineral particle i nputs from seabird influenced ice- and vegetation-free surfaces. Carbon-14 dating, carbon-13/carbon-12 isotopic ratios and detailed SOM investigations are recommended for future studies to improve our current understanding of SOM origin, accumulation, and transformation. The Von Post humification sc ale is not an adequate indicator for estimating humification in antarctic o rganic soils. Even small areas or percentages of organic soils strongly aff ect the carbon and nitrogen stocks at landscape scales. (C) 2000 Elsevier S cience B.V. All rights reserved.