A Solar Daily Variation in Oxygen Consumption of the Embryonated Egg.

Abstract

O2-Consumption of individual embryonated chick eggs was measured continuously for 3 days in constant conditions, including pressure, with a Brown automatic recording respirometer. Superimposed on linear daily trend for each of the 3 days studied, days 5, 6, and 8 of incubation, was a statistically significant mean daily pattern in hourly rates possessing a characteristic morning minimum and 7 p. m. maximum. The mean range of the daily fluctuation was about 15% of mean daily rate. The 7 p. m. deviation from daily trend was related to the concurrent 2-6 p. m. rate of local atmospheric pressure change. In view of the great variability in stage of morphological development for chick eggs of the same incubational age, the sharply defined 7 p. m. maximum, and its correlation to atmospheric pressure change, indicate that the solar daily variation in metabolism is a response to some subtle geophysical rhythm.