MICROBIAL COMMUNITY-BASED MEASUREMENTS TO ESTIMATE HEAVY-METAL EFFECTS IN SOIL - THE USE OF PHOSPHOLIPID FATTY-ACID PATTERNS AND BACTERIAL COMMUNITY TOLERANCE

Microbial community-based measurements to detect effects of heavy meta ls in soils rely on the premise that metal toxicity exerts a selection pressure, which induces a change in the composition of the community. The phospholipid fatty acid (PLFA) composition gives an integrated pi cture of all living organisms in the soil, and changes in the PLFA pat tern of the soil indicate an altered species composition due to, e.g. metal toxicity. An increased bacterial community tolerance to metals a lso indicates an altered community composition, with tolerant organism s becoming more abundant relative to sensitive organisms. The use of t hese two techniques is described, and their advantages and disadvantag es as monitoring tools are discussed and exemplified by field data and laboratory experiments from different soils.