Effects of fluoranthene and ambient oxygen levels on survival and metabolism in three sibling species of Capitella (Polychaeta)

Abstract

The successful persistence of Capjtella spp. in disturbed and/or oil-polluted habitats is widely known, but demographic adaptations might be only part of the explanation and little is known about differences among species. The present study investigates ecophysiological effects of the common PAH (polycyclic aromatic hydrocarbon) fluoranthene (FLU) on juvenile and adult survival, comparing 3 sibling species of CapiteUa (Polychaeta; Capitellidae). Subsequently, the influence of FLU on the aerobic and anaerobic metabolism in the most 'sensitive' species, CapiteUa sp. S, and most 'tolerant' species, Capitella sp. I, was assessed. Oxygen uptake and internal succinate concentrahon (an indicator of anaerobic metabolism) were measured after short-term (7 h) and long-term (2 wk) FLU pre-exposure (100 pg g-'). FLU exposure reduced mean survival times of juveniles (4 d old) of all sibling species, but tolerance varied among the 3 species of Capitella adults. Capitella sp. S, originally collected from 'clean' oxygen-nch North Sea intertidal sedments, was most sensit~ve and CaplteUa sp. M, and Capitella sp. I, which is the most opportunistic of the sibling species described to date, were most tolerant. In Cap~tella sp. S, O2 uptake decreased at lower ambient oxygen levels and increasing FLU concentrations increased oxygen consumption. Similarly, O2 uptake decreased at lower ambient oxygen levels in Capitella sp-I; however, FLU concentrations had no effect on oxygen uptake. For both species, anaerobic metabolism increased with declining ambient oxygen levels, and was influenced by FLU exposure in CapiteUa sp.