Fig. 1. Conceptual diagram of the experimental setup. PE-temp, Peltier Effect temperature cabinet and controller; H, water reservoir (for air hydration); RC, respirometer chamber; GS1–GS4, gas changeover solenoids under computer control via ExpeData; MFC, mass flow control valve and electronics unit; S, scrubber. Large scrubber=Drierite/Ascarite/Drierite for removal of H₂O and CO₂ from normoxic air; small scrubber=Ascarite for removal of trace CO₂ from the selected gas stream. NV, needle valve; CO₂, CO₂ analyzer; MFM, mass flow meter; X, closed (no gasflow). The light emitter and sensor used for detection of activity in the respirometry chamber are not shown. See text for details.