Effects of short-term air exposure on the oxygen and acid-base status of hemolymph in the akoya pearl oyster, Pinctada fucata martensii

アコヤガイのヘモリンパ液の酸塩基平衡に及ぼす大気への短期曝露の影響

Effects of short-term air exposure on the oxygen and acid-base status of hemolymph in the akoya pearl oyster, Pinctada fucata martensii

We investigated the hemolymph oxygen and acid–base status of akoya pearl oysters, Pinctada fucata martensii, exposed to air for a short time (4 h) to elucidate the acid–base balance and CO_2 dynamics. The hemolymph O_2 partial pressure (Po_2) in air-exposed akoya pearl oysters decreased from 88.7 torr (mean value) to 29.4 torr at 1 h, and the low Po_2 continued for the next 3 h during air exposure. The hemolymph pH decreased from 7.586 to 7.082 during air exposure for 1 h and reached 6.851 at 4 h. The hemolymph CO_2 partial pressure increased from 0.9 torr to 4.4 torr at 1 h and reached 7.3 torr after 4 h of air exposure. The hemolymph bicarbonate concentration and calcium ion concentration at 0 h (control) were 1.9 mM/L and 9.0 mM/L, respectively, and these properties did not significantly change during air exposure. From these results, it was determined that the akoya pearl oysters had hypoxemia caused by hypoventilation at an early phase of the short-term air exposure. The akoya pearl oysters inhibited the discharge of CO_2 by hypoventilation, and respiratory acidosis was caused due to the excessive accumulation of CO_2. Bicarbonate was not mobilized from the shell valve into the hemolymph during the short-term air exposure.

Creators Handa Takeshi

Creators Araki Akira

[ISSN]0370-9361