Metabolic Responses of the Sea Anemone Bunodosoma cavernata (Bosc) to Declining Oxygen Tensions and Anoxia

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Abstract
The respiratory responses of the sea anemone Bunodosoma cavernata to declining oxygen tensions were measured polarographically. In general, the pattern of vs. Po2 is similar to what has been observed for other sea anemones. Exposure to 18 h of anoxia resulted in a consistent elevation of oxygen consumption. This apparent oxygen debt was further investigated manometrically. The magnitude of the oxygen debt increased as the duration of exposure to anoxia was increased. The postanoxic elevation of was also accompanied by an ammonia debt. Alanine levels in the tissues of B. cavernata rose 20-fold during the time course of anoxia while succinate and L-lactate did not accumulate. Although glutamate levels increased slightly, none of the other components of the amino acid pool decreased, suggesting that the amino group used in alanine synthesis is probably derived from general protein turnover. At the end of 4 days of anoxia, propionate levels were elevated above the levels in aerobic, control sea anemones. During postanoxic recovery, a decrease in alanine levels in the tissues of B. cavernata was observed. The decline in alanine completely accounted for the additional ammonia excreted during recovery. The results of this study show that metabolic oxygen and ammonia debts are distinct features of the recovery of B. cavernata from anoxia.