Abstract
A microcosm study was carried out in order to determine effects of raw sewage of pulp and paper industry from Tunisia on nematodes of Ghar El Melh lagoon. Four sedimentary concentrations of raw sewage, D1 (25%), D2 (50%), D3 (75%), D4 (100%), were applied during 30 days of exposure. Under stress, abundance of nematodes increased significantly, especially for the highest doses. Univariate indices of diversity showed a significant decrease which suggests species differential responses versus pollution. Multivariate analyses demonstrated that responses of nematode species to raw effluents from paper industry varied. Under stress, the presence of Neochromadora poicilosomoides, Prochromadorella neapolitana, Anticoma acuminata, Paramonohystera pilosa and Chromadorina metulata was reduced and they were categorized as sensitive species. In comparison, Theristus pertenuis, Daptonema fallax, Paracomesoma dubium and Marylynnia stekhoveni increased at all levels of raw effluents and may be classified as tolerant