Environmentally sensitive worms

Posted on December 9, 2010

A standard way of assessing water quality in streams is to use the River Pollution Index (RPI), which is calculated from measurements of dissolved oxygen, biological oxygen demand, suspended solids and ammonia. However, while chemical indicators such as RPI reflect current levels of contamination they provide no information on the history of pollution or its actual environmental impact at a given site. These limitations can be overcome by the parallel use of biological indicators . Nematode worms are good indicators of ecological condition because they are very abundant, have a high diversity of species and feeding types, and play a prominent role in benthic food chains. After examining samples from the Beigang River, Taiwanese researchers found that the highest numbers of nematode families, genera and feeding types occurred at contaminated (high-RPI) sites. The dominance of “coloniser” nematode species (i.e., those with relatively high reproductive rates) was also high at contaminated locations, regardless of the type of pollution. Members of the nematode family Monhysteridae were dominant at polluted sites but never occurred at unpolluted sites. These results suggest that nematode abundance and community structure can be used as reliable bioindicators of river water quality.

Reference:  Wu, H.C., Chen, P.C. &, Tsay, T.T. 2010. Assessment of nematode community structure as a bioindicator in river monitoring.  Environmental Pollution 158, 1741–1747.