Response of spionid polychaetes under different concentrations of crude oil in an ex situ experience (Patagonia, Argentina)

Abstract

The abundance of certain spionid speciescan be closely linked to environmental disturbancesproducing quantifiable changes in community structure.We hypothesize that in stress conditions, thespionids would tend to localize in the upper level ofthe sedimentary column near to the sediment?waterinterface. The aim of this work was to analyze, throughan ex situ experiment, the effect produced by twoconcentrations of crude oil on the spionids at differentdepths of the sedimentary column and identifypossible pollution indicators. A simulated oil spill attwo input levels was carried out in the laboratory for30 days. The effect of the adding of crude oil wassignificant only in the superior level of the sedimentarycolumn. The differences in the abundancebetween levels by experimental conditions weresignificant in all the cases. Sensitive species likeScolelepis (Parascolelepis) sp. and Rhynchospio glutaeadisappeared while other species like Boccardiaproboscidea had a higher resistance to the addition ofcrude oil. This study constitutes the first characterizationof spionid assemblages of the Patagonian coastsaltered by crude oil in sediments, and the firstidentification of species, which can be useful pollutionindicators.