BIODIVERSITY AND DECISION MAKING: BIOLOGICAL AND SOCIO-ECONOMIC PERSPECTIVES

FIBRE SYMPOSIUM AUGUST 24-26.8.

POSTER ABSTRACTS
 

5. MICROBIOLOGY AND BIOTECHNOLOGY 5.3  IMPACT OF AIRBORNE METAL POLLUTION ON MICROBIAL COMMUNITY STRUCTURE IN CONIFEROUS SOIL R. Maarit Niemi, Jukka Ahtiainen, Tarja Sarjakoski, Eija Schultz and Pekka Vanhala Finnish Environment Institute, Helsinki The impact of airborne pollution on microorganisms and their activity in boreal coniferous soil was measured in two areas in Southern Finland. The Harjavalta site is characterized by pollution from a copper and nickel smeltery emitting SO2, Cu, Ni, and Cd. The Koverhar area is contaminated by an iron smeltery emitting SO2, NOx, Cd, Pb, Zn, Fe, As and chalc. ATP content and soil respiration decreased towards the pollution source in the Harjavalta gradient but were either not affected or increased in the exposed site at Koverhar. The semiquantitative API Zym test kit was used to assess enzyme activities. The activities were low in all samples but tended to decrease due to the pollution in Harjavalta. Quantitative enzyme activity measurements showed decreases in the activities in invertase, xylanase, arylsulphatase and acid phoshatase when progressing towards the pollution source in Harjavalta. When enzyme activities were quatitatively measured in Koverhar area, dublicate composite samples showed no differences in soil respiration between the exposed site and the control site. ATP content was slightly decreased in the exposed site, but replicate samles showed remarkable variation. Alkaline phosphatase and xylanase were decreased but invertase and arylsulphatase were increased in the exposed site compared with the control site. The levels of acid phosphatase were similar in both sites.  In Harjavalta heavy metal pollution gradient, relative numbers of colony-forming bacteria and fungi decreased as a function of pollution. However, in the most heavily polluted site adaptation of bacterial and fungal flora to heavy metals was demonstrated by cultivating heterotrophic bacteria and fungi on agar media supplemented with heavy metals (Cu, Pb, Zn, Ni) and by cultivating soil samples from different sites in liquid R2A medium containing Cu, Ni and Zn in different combinations.  DNA was isolated from different sites in the Harjavalta gradient and its 16S rDNA fragments amplified using Y1 (modified with GC-clamp) and Y2 primers. Metal-resistant bacteria were isolated from the same sites and their isolated DNA was amplified using the same primers. Amplicons were separated with DGGE. DGGE revealed more bands of 16S rDNA fragments in the control soil samples than in the exposed sites. Three clusters were observed of nine heavy metal resistant bacterial isolates on the basis of DGGE. However, these were not dominant among soil bacteria in exposed area.