Fig. 1. Simplified diagram of the respirometry system. Not to scale. Data acquisition system not shown. Oxygen and nitrogen tanks are at the bottom; each opens into a manifold through which oxygen or nitrogen flow can be controlled with a needle valve (NV). MFC, mass flow control valve (associated controller not shown). Dashed rectangle is temperature-controlled cabinet (Peltier effect; PE-temp). S, scrubber (H₂O and CO₂); EQ, equilibration coil; RC, respirometry chamber; T, thermocouple; H₂O, water vapor analyzer; CO₂, carbon dioxide analyzer. See text for details.