To cope with dramatic seasonal changes in their environment, animals at high latitudes must be able to keep track of time. The information is used to anticipate and prepare for forthcoming seasonal changes and to initiate biological events, such as reproduction and migration, that need to be correctly timed.
The biological timing depends partly on endogenous, biological clocks that organize physiology and behavior on a daily and annual scale, and partly on environmental cues that continuously adjust (entrain) the clocks. The seasonal change in photoperiod and its effect on the secretion of the “night” hormone melatonin provides the most reliable clock and calendar information, and hence represents the most important entrainment of the clocks.
Our studies in chronobiology encompass three main goals:
1) describe seasonal rhythms in physiology and behavior of high-latitude fish, birds and mammals together with the molecular and hormonal mechanisms that underpin these rhythms
2) use the extreme seasonality of high-latitude animals as a model to reveal fundamental new knowledge about biological rhythms in general
3) investigate how seasonal rhythms entrained by photoperiod may work in a scenario with global warming that will lead to changes in the phenology of annual environmental changes (e.g. earlier spring) but not in photoperiod.