Preferential intracellular pH regulation is a common trait amongst fishes exposed to high environmental CO2

• DOI: 10.1242/jeb.208868
• Publication Date: 2020-03-03T18:39:03Z
• Authors: R. B. Shartau; D. W. Baker; T. S. Harter; D. L. Aboagye; P. J. Allen; A. L. Val; D. A. Crossley; Z. F. Kohl; M. S. Hedrick; C. Damsgaard; C. J. Brauner
• Keywords: Trait

Acute (<96 h) exposure to elevated environmental CO2 (hypercarbia) induces a pH disturbance in fishes that is often compensated by concurrent recovery of intracellular and extracellular (pHi pHe, respectively; coupled regulation). However, regulation may be limited at partial pressure (PCO2 ) tensions far below levels some naturally encounter. Previously, four hypercarbia-tolerant had been shown completely rapidly regulate heart, brain, liver white muscle pHi during acute >4 kPa PCO2 (preferential regulation) before pHe compensation was observed. Here, we test the hypothesis preferential widespread strategy acid-base among fish measuring 10 different species are broadly phylogenetically separated, spanning six orders, eight families genera. Contrary previous views, show most common for within these severe hypercarbia this associated with increased tolerance. This suggests confer tolerance respiratory acidosis hypercarbia, propose it an exaptation facilitated key evolutionary transitions vertebrate evolution, such as evolution air breathing.