SUPPRESSION OF SOIL MICROORGANISMS BY EMISSIONS OF A MAGNESITE PLANT IN THE SLOVAK REPUBLIC GUIDO KAUTZ 1 , MARTIN ZIMMER 2∗ , PETER ZACH 3 , JÁN KULFAN 3 and WERNER TOPP 1 1 Zoologisches Institut, Terrestrische Ökologie, Universität zu Köln, Germany; 2 Zoologisches Institut der Christian-Albrechts-Universität zu Kiel, Biologiezentrum, Germany; 3 Department of AnimalEcology, Institute of Forest Ecology, Slovak Academy of Sciences, Zvolen, Slovak Republic ( ∗ author for correspondence, e-mail: mzimmer@zoologie.uni-kiel.de) (Received 28 October 1998; accepted 11 January 2000) Abstract. In April 1996, we collected soil samples in the vicinity of a magnesite plant at Lubeník, southern Slovakia, and screened them for soil microbial biomass and activity. Six investigated sites were chosen along a transect, with distances ranging from 600 to 8000 m from the plant, to represent a gradient of intoxication. Soil microbial cellulase activity, respiration, biomass, metabolic quotient of the soil microbiota, and numbers of platable fungi increased with increasing distance from the plant, i.e. decreasing degree of intoxication. The observed gradients of soil microbial characteristics of the investigated sites reflect the physico-chemical soil parameters and the floristic characteristics of these sites, and may be used to predict transitory changes during amelioration. Keywords: biomonitoring, magnesite intoxication, soil microbial activity, soil microbial biomass, ‘space for time’ 1. Introduction Toxic effects of magnesite plants on their surroundings have been discussed thor- oughly during the last years (Raman et al., 1993; Bell, 1996). Chemical com- positions of soils near magnesite plants and vertical gradients of intoxication are well-known (Bublinec, 1973; ˘ Sály and Mihálik, 1984). However, knowing the chemical properties of the soil alone is insufficient for describing the responses of a biotic system (Górny, 1976; Graefe, 1991). Hence, studies of biotic soil activ- ities allow a more accurate evaluation of the soil quality. Soil microorganisms are important for plant growth (Stephens et al., 1994; Alphei et al., 1996) and are beneficial for the nutrition and development of the soil animals (Ullrich et al., 1991; Zimmer and Topp, 1997, 1998; Zimmer, 1999; Kautz et al., 2000). Moreover, soil microorganims and soil invertebrates as well improve the nutrient availability in soils (Teuben and Roelofsma, 1990; Kautz and Topp, 1998, 1999, 2000). There- fore, an impact of magnesite emissions on soil microorganisms should affect the nutritional status of the vegetation and the survival of soil invertebrates. Microbial parameters of soils will reflect the actual condition for the entire biotic system. The objectives of the present study were (1) to screen for characteristics of Water, Air, and Soil Pollution 125: 121–132, 2001. © 2001 Kluwer Academic Publishers. Printed in the Netherlands.