Impact d’un lubrifiant minéral sur la structure trophique des peuplements de nématodes libres marins de la lagune de Ghar el Melh: étude microcosmique

Abstract

A microcosm experimentation was carried out to evaluate the influence of mineral lubricant before
and after its use on the trophic structure of a free-living nematode communities from a Tunisian lagoon (Ghar El Melh).
A concentration of 1mg kg-1 of the pollutant was tested to evaluate its effects after 40 days of exposition. The results obtained revealed that the not selective deposit feeders (1B), most abundant in control microcosm, were very affected and their abundance decreases significantly in response to mineral-oil contamination. Selective deposit feeders (1A) showed significantly increase in dominance before and after use of the lubricant and seemed more resistant to this contaminant. The diatom feeders (2A) were more abundant in treated microcosms. The omnivores-predators (2B) seemed to be not sensitive to the contaminant and were affected by the lubricant added before use. The trophic index (Sq2) and the 1B/2A ratio have significantly decreased for all microcosms treated with mineral lubricant.