Table 1.

Extracellular and intracellular acid–base status in eels exposed for at least 6 weeks to water CO2 partial pressures (PwCO2) of approx. 0.8 mmHg (ambient control), 15±1 mmHg, 30±1 mmHg or 45±1 mmHg

PwCO2 (mmHg)
Approx. 0.815±130±145±1
a[CO2] (mmol l-1)13.0±1.6a41.6±1.6b59.8±2.6c74.7±4.0d
pHa7.89±0.04a7.75±0.02a,b7.63±0.02b7.57±0.04b
PaCO2 (mmHg)3.7±0.3a17.5±1.3b35.0±1.7c47.5±2.9d
a[HCO3-] (mmol l-1)12.8±1.5a40.8±1.6b58.2±2.6c72.5±4.1d
White muscle pHi7.13±0.05a7.03±0.02a7.03±0.05a7.01±0.03a
Heart pHi7.02±0.03a7.10±0.03a7.18±0.03a7.13±0.01a
  • 1 mmHg=approx. 0.01316 kPa.

    a[CO2], arterial blood total CO2 content; pHa, arterial pH; PaCO2, arterial CO2 partial pressure; a[HCO3-], arterial bicarbonate concentration; pHi, intracellular pH.

    Values are means ± 1 S.E.M. of six determinations, except for blood acid—base variables, where N=7 at PwCO2 of 30 mmHg and N=5 at PwCO2 of 45 mmHg.

    A common superscript indicates no significant difference between groups (P>0.05).