Anaerobic respiration in the polychaete Euzonus (Thoracophelia) mucronata

The intertidal polychaete Euzonus mucronata (Treadwell) is found in great numbers within beach sands that undergo periodic anoxia. Short-term exposures (2 to 4 h) to anaerobicity are withstood through the use of a supply of oxyhemoglobin to support continued aerobic metabolism. Longer periods of environmental anoxia activate an anaerobic metabolism capable of sustaining life for up to 20 days, and characterized by the excretion of succinate and propionate. These two mechanisms appear to be adaptations to the variations in occurrence and duration of anoxia within the intertidal sands inhabited by E. mucronata.Supported by an NSF Graduate Fellowship, 1973–1974.