Radiocesium storage in soil microbial biomass of undisturbed alpine meadow soils and its relation to ~(137)Cs soil-plant transfer

摘要

This study focuses on radiocesium storage in soil microbial biomass of undisturbed alpine meadow sites and its relation to the soil-to-plant transfer. Soil and plant samples were taken in August 1999 from an altitude transect (800-1600 m.a.s.l.) at Gastein valley, Austria. Soil samples were subdivided into 3-cm layers for analyses of total, K_2SO_4-extractable and microbially stored ~(137)Cs. Microbial biomass was measured by the fumigation extraction method, and fungal biomass was quantified using ergosterol as biomarker molecule. In general, the quantity of ~(137)Cs stored in the living soil microbial biomass was relatively small. At the high-altitude meadows, showing high amounts of fungal biomass, microbially stored ~(137)Cs amounted to 0.64 ± 0.14 kBq m~(-2) which corresponds to about 1.2-2.7% of the total ~(137)Cs soil inventory. At lower altitudes, microbial ~(137)Cs content was distinctly smaller and in most cases not measurable at all using the fumigation extraction method. However, a positive correlation between the observed soil-to-plant aggregated transfer factor, microbially stored ~(137)Cs and fungal biomass was found, which indicates a possible role of fungal biomass in the storage and turnover of ~(137)Cs in soils and in the ~(137)Cs uptake by plants.