SOLUBLE CARBOHYDRATE AND ORGANIC-ACID CONTENT OF SOILS AND ASSOCIATEDMICROBIOTA FROM THE WINDMILL ISLANDS, BUDD COAST, ANTARCTICA

In the cold Antarctic environment labile organic compounds may accumul ate in soil due to relatively low utilization rates by heterotrophic m icroorganisms. Microbial fermentation of these compounds might contrib ute to the development of strongly acid soils. To test this and assess concentrations, extracts of a range of soils in the Windmill Islands, Budd Coast were analysed by GLC and HPLC for the presence of low mole cular weight sugars, polyols and organic acids. Concentrations of suga rs and polyols up to 3300 mg g-1 were detected in cryptogam dominated soils. Some, such as trehalose, may have principally originated in the soil microflora. Soils from occupied penguin rookeries were found to possess oxalic, acetic, propionic and succinic acids at levels up to 1 000 mg g-1 soil. Most other soils, however, lacked these acids at dete ctable levels (1-5 mg g-1 soil). No correlation was established betwee n organic acid accumulation and soil pH although those dominated by mo ss and lichen had been acidified significantly when compared with barr en soils. Thus while substantial pools of these readily utilized carbo hydrates were probably present in cryptogam dominated soils, there was little accumulation of organic acids which could account for the acid ity of mineral soils typical of the Windmill Islands.