Acid-base balance of hemolymph in disk abalone Haliotis (Nordotis) discus discus in normoxic conditions
2019
Handa, T. (National Fisheries University, Shimonoseki City, Yamaguchi Pref. (Japan). Department of Applied Aquabiology) | Araki, A. | Yamamoto, K.
We examined hemolymph pH, total CO2 content (Tsub(co2)), CO2 partial pressure (Psub(co2)), and bicarbonate concentration ([HCO3sup(-)]) in order to evaluate the acid-base balance of disk abalone Haliotis (Nordotis) discus discus in normoxic conditions. Hemolymph from disk abalone submerged in experimental seawater was collected anaerobically from the vein located near the margin of the shell using a cannula. The mean values of hemolymph pH and Tsub(co2) were 7.320 and 1.78 mM/L, respectively. The apparent dissociation constant of carbonic acid (pKapp) was estimated using the following equation: pKapp = -7.322 + 2.367・pH + 0.176・pHsup(2) - 0.0335・pHsup(3). Using a co2 (37.13 μM/L/torr) and pKapp determined in this study, the hemolymph Psub(co2) and [HCO3sup(-)] were calculated as 4.21 torr and 1.63 mM/L, respectively. The non-bicarbonate buffer value was 3.62 Slykes. These hemolymph properties were compared with those of other molluscan species, Pteriidae bivalves. Disk abalone could have a hemolymph acid-base balance that is similar to other Haliotidae, and have higher buffer capacity of non-bicarbonate buffer system than bivalves.
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