Temperature sensitivity of metabolism in offshore and intertidal onuphid polychaetes

Acclimated metabolism-temperature curves have been constructed for 4 populations of the intertidal onuphid Diopatra cuprea, and for the 2 offshore species Hyalinoecia tubicola and H. artifex. The intertidal species shows greater temperature sensitivity than its offshore relative, despite its presumed adaptation to thermally unstable habitats. Temperature changes considerably in excess of natural fluctuations do not greatly alter metabolic rates in Hyalinoecia. However, the range of thermal tolerance in these two species is considerably reduced.