A mesocosm analytical study on the ecological interactions of certain benthos in response to the biodeposition and bioturbation activities of the freshwater mussel <i>Lamellidens marginalis</i> (Lamarck)

Abstract

The biotic influences of the biodeposition and bioturbation activities of the freshwater mussel Lamellidens marginalis (Lamarck) on the ecological interactions between certain co-existing benthic invertebrates leading to variations in their population densities were studied through a lake mesocosm experiment. The benthic organisms whose densities were monitored include nematodes, oligochaetes, chironomids, small snails and sediment dwelling colony-forming bacteria. Five exclusion (without mussels) and five experimental (with mussels) mesocosms were maintained up to 60 days (d). Even though there were no significant variations in the population densities of the organisms in the exclusion mesocosms, those of the experimental mesocosms showed significant variations. However, the patterns of variations of the population densities were different for the various organisms studied. The study clearly indicated the influences exerted by L. marginalis on the population richness of the co-existing benthic organisms. The study also revealed the probable trophic interactions between the various organisms studied.

Key words: Biodeposition, bioturbation, ecological interaction, mesocosm, population density, Lamellidens marginalis.