Acid-base balance in the sea mussel, Mytilus edulis. III. Effects of environmental hypercapnia on intra- and extracellular acid–base balance
Lindinger, M.I.; Lauren, D.J.; McDonald, D.G. (1984). Acid-base balance in the sea mussel, Mytilus edulis. III. Effects of environmental hypercapnia on intra- and extracellular acid–base balance. Mar. Biol. Lett. 5(6): 371-381
In: Marine Biology Letters. Elsevier: Amsterdam. ISSN 0165-859X, more
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| Authors | | Top |
- Lindinger, M.I.
- Lauren, D.J.
- McDonald, D.G.
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| Abstract |
Exposure of M. edulis L. to normoxic-hypercapnic seawater (PCO2 = 6.5, 13.0, and 26.0 mm Hg) for 24 h produced an elevation in hemolymph [H+], [Ca2+], [HCO3-], [HN4-], and PCO2. Simultaneous measurement of intracellular pH (pHi) at a PCO2 of 26 mm Hg showed that pHi followed hemolymph pH but was maintained about 0.4 pH unit lower. A large (6.37 .+-. 0.65 meq. H+/L) nonrespiratory component to the intracellular acidosis developed within 0.5 h of exposure to PCO2 of 26 mmHg. At all CO2 levels, the initial drop in pH was partially compensated over the remaining 23.5 h of CO2 exposure by increases in extracellular and intracellular bicarbonate, while PCO2 remained constant. About 70-80% of the additional bicarbonate was produced by the dissolution of shell and body fluid stores of CaCO3; the remainder may have resulted from intracellular to extracellular ion exchanges and/or transepithelial ion exchange processes. Acid-base regulation in M. edulis is largely passive in response to environmental hypercapnia. Even in the presence of O2, CO2 appears to exert a major effect on cellular metabolism in Mytilus. |
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