INSITU RECORDINGS OF OXYGEN-CONSUMPTION RHYTHMS IN CARCINUS-MAENAS

1. 1. A portable, battery-operated, programmable recording respirometer, operating on an intermittently closed system was designed and built for this work. A clock-operated, three channel photoelectric timer, control unit, strip recorder and oxygen meter make up the base unit. A small d.c. pump, control valve, oxygen electrode and animal chamber make up the submersible portion of the respirometer. 2. 2. Individual crabs were monitored for periods of 18 hr in situ and their oxygen consumption rhythms analized by autocorrelation and graphical methods. 3. 3. Although individual patterns varied, there was a marked correlation between the major peaks and the lowering of temperature with the flooding tide. Other peaks were associated with sunset, but none consistently with high tide or darkness. 4. 4. The average level of in situ rates was markedly below those recorded in the laboratory, suggesting that laboratory rates are raised by excitement. © 1979.