Natural light effects on Platynereis chronobiology

From the day-night cycle to the change of seasons, life on earth is exposed to various environmental cycles and organisms have evolved internal clock systems to anticipate these. We humans become painfully aware of this after long flights when we experience a jetlag, because our inner diel clock does no longer match the outside time. The awarding of the 2017 Nobel Prize to the scientists that did pioneer work to unravel the molecular basis of clock systems reflects their importance in nature and for human health. Research on clock systems is still largely focused on laboratory work, but environmental rhythms in the natural habitat are much more complex and this can strongly affect species rhythmicity. This is especially true for the marine environment where, aside diel and seasonal cycles, tides and the lunar cycle have resulted in a variety of biological rhythms. Light is a central cue for the synchronization of internal clocks and animals and plants have evolved a large variety of different light receptors whose response profiles cover the different wavelengths of light. In our project The impact of natural environmental light on the chronobiology of Platynereis dumerilii wildtype and mutant worms we work with the marine worm Platynereis dumerilii, which possesses two independent internal clocks, one for the day-night and one for the monthly lunar cycle. We aim to investigate how the functioning of the worms clocks and its rhythmic behavior differ between worms kept under laboratory lights and worms kept outdoors under natural light conditions. To better understand which wavelengths of light are most important for rhythmicity, we will do this also with genetically modified worms that lack different kinds of light receptors and thus will likely have less information about the environmental light. With our work we will learn what aspects of the environment are essential for the worms rhythmicity. Biological rhythms can shape entire ecosystems by orchestrating species interaction in time. It is therefore crucial to understand the functioning of the clock systems evoking these rhythms. This will also be essential to predict how clocks and biological rhythms will respond to changing climate conditions. The field work could further help to better understand the negative effects of artificial lighting on human brain chemistry and health.