Physics Department Seminar University of Alaska Fairbanks

J O U R N A L    C L U B


Investigating the disturbance in the light and dark cycle due to external light pulses on seasonal species

Douglas Ogata
Physics Dpartment UAF



Environmental conditions such as photoperiod regulate mammals’ physiology. Of particular interest is mammals in the Arctic due to the extreme conditions. To overcome those extreme conditions and save energy, Arctic ground squirrels hibernate. Hibernation is characterized by a low metabolic rate, which is seasonally modulated. However, in captivity, hibernation seems to be sensitive to disturbances. We think that short light exposures in the dark phase interfere with the set photoperiod leading to unusual hibernation patterns. We developed a simple 0D model of a possible hibernation process to investigate this behavior. A circadian rhythm model based on the time delayed differentials that results in the diurnal cycle regulation of EYA3 is used as a drive for the production of T3. T3 is hypothesized to increase the metabolic rate in summer by EYA3 activation. Additional light pulses effectively extend the total light exposure, which, subsequently, induces higher level of EYA3 production. This might suggest a tendency for squirrels to emerge from hibernation sooner. However, there is not much difference in the fall when the squirrels tend to go into hibernation. Implications of this may affect how to care for squirrels under hibernation during extensive multi-year studies.


Friday, 10 March 2017

Globe Room, Elvey Building

3:45 PM