Fabio Piccolin presented evidence for a seasonal modulation of the circadian clock in Antarctic krill at the 3rd International Symposium on Krill in June 2017 in St. Andrews, Scotland. Find the talk here.
Abstract: In krill, photoperiod may modulate daily rhythms of oxygen consumption and regulate levels of transcription of genes involved in metabolism, motor activity and molting. It is therefore likely that photoperiod plays a role in the transitions between active and quiescent metabolic states which have been observed in krill in natural conditions at the end of summer (active to quiescent) and at the end of winter (quiescent to active). A circadian clock informed by photoperiod may be present and active in krill, regulating daily rhythms of transcription, metabolic activity and physiology. The clock might be involved in the photoperiodic-dependent modulation of metabolic activity and therefore contribute to the organization of seasonal adaptive strategies in krill. To examine the link between the circadian clock, the modulation of metabolic activity and photoperiod, we measured clock gene expression in krill adapted to different photoperiodic conditions, together with gene expression of a selection of metabolic genes and genes involved in the regulation of putative seasonal processes. Our results show that the activity of the clock can be modulated by photoperiod together with that of key metabolic genes, both at the daily and at the seasonal scale. This indicates that the circadian clock may contribute to the regulation of seasonal responses in krill and that photoperiod may be the main factor involved in such process.