Response of meiofauna and nematode communities to increased levels of contaminants in a laboratory microcosm experiment

This study was undertaken to assess the response of meiofauna and nematode (multispecies) associations in terms of density, diversity, and composition to different environmental contaminants and also to evaluate the use of meiofauna and nematodes as indicators in pollution monitoring. Sediment was collected from the mouth of the Swartkops River estuary and defaunated by successive freezing and thwarting. The sediment was then subdivided into flasks and treated with different contaminants (organic carbon, Zn, Cu, Pb, Fe) at different concentrations, before meiofauna-rich sediment was added to each of them. The setup was allowed to mature for 32 days. Various biological indices were used to assess the biological status of the nematode communities in the laboratory experiment. Nematode identification was done to the genus level. The results indicate that higher concentrations of heavy metals and organic carbon had an impact on the nematode density, diversity, and community structure. Nematode genera such as Axonolaimus, Theristus, and Paramonohystera were found to be tolerant to metal pollution. This study also observed that nematode communities react differently to metal and organic pollution.