Trophic structure of ecosystems and ecotoxicology of soil organisms

Abstract

Studies on the ecotoxicology of soil organisms have led to the revision of views on the trophic struc- ture of ecosystems. It was found that the microbial link is obligatory and controls the migration of toxicants and their effects in the food chain. Differences in effects are accounted for by both the physioMgical stability of organisms and their affiliation with relatively independent and biogeochemically closed ecosystems differing in their spatiotemporal scales. The latter form a hierarchical three-level structure: ecosystems of unicellular organisms---ecosystems of small multicellular organisms--the ecosystem of large multicellular organisms, or a biogeocenosis. Trophic networks within the structure are united by ecosystemophagy as the type of feeding of large multiceUular organisms, and this accounts for the importance of the latter as indicators of long-term changes in a biogeocenosis.