A Volumetric Respirometer for Studies of Aerial and Aquatic Oxygen Consumption

The respirometer described here is a volumetric plastic respirometer of the kind in which the respiration chamber is balanced against the compensating chamber through a manometer drilled in a block of perspex as first described by Scholander (1950). The apparatus is an improved version of a respirometer described by Micallef (1966, 1967) which has a respiration chamber with a built-in magnetic stirrer to agitate the water and equilibrate it with the gas phase when aquatic respiration is being measured. Use of an internal stirring device obviates the need for shaking the whole apparatus. Magnetic stirring is ideal for a closed system like a respirometer because a shaft seal is not required. The present design embodies a submersible fluid-driven magnetic stirrer for trouble-free operation and a microdosimeter with a dial indicator which gives direct readings of oxygen consumption. The respiration and compensation chambers are assembled on a baseplate. The baseplate takes one size of chambers but the manometer block can be dismounted and used with different baseplates.