zebrafinch_ageing
The overarching aim of our project is to provide a holistic understanding of disruption of circadian rhythms of wild animals by artificial light at night (ALAN). Our research will investigate the extent to which urban light pollution disrupts circadian rhythms of behaviour and physiology, whether the endogenous circadian clock regulating such rhythms is directly affected, whether circadian disruption is associated with health consequences, and whether selected lighting strategies can mitigate adverse effects. The project investigates an urgent question as the natural alternation of light and darkness is increasingly compromised by the spread of ALAN associated with progressive urbanization, but potentially negative consequences are still largely untested. Negative consequences of ALAN are likely since most organisms have evolved their daily rhythms over millions of years in a world where daily cycles of light and darkness have been extremely predictable. Indeed, one of the most pervasive features of life on Earth, from bacteria to humans, is the ticking of endogenous circadian clocks that are synchronized to external light cues from the sun and regulate most diel biological functions. Despite the increasing interest in the ecological effects of light pollution, we still lack an understanding of the extent to which it might cause disruption of circadian rhythms across wild species living in urban areas, what the outcomes of such disruption will be, and what we can do about it. As with other anthropogenic stressors, it is likely that species differ greatly in their responses. Hence, in this project we will firstly use biotelemetric and physiological approaches in a carefully selected range of wild bird species to assess how urban life affects circadian rhythms. We will then use experiments with captive birds to test the effects of ALAN on the endogenous circadian clock and on targeted physiological pathways related to health. Last, we will examine the potential for mitigation of circadian disruption through partial night lighting. By integrating these approaches, our project will enable the most comprehensive understanding of both the scale and the mechanisms underlying the problem of light pollution to date, and explore the basis for a novel mitigation strategy. We will achieve this by addressing the following four questions: 1. To what extent are rhythms of avian behaviour and physiology affected by ALAN, and do effects differ between selected species, seasons, and urban vs. non-urban habitats? 2. Does exposure to ALAN lead to faster and weakened endogenous clocks? 3. Does ALAN affect key physiological processes that may underlie poor health, including immunity, inflammation and telomere dynamics? 4. Can we maintain natural circadian rhythms in birds exposed to ALAN via part-night lighting?  The dataset deposited here refers to objective 4, in which we performed an experiment with zebrafinches to test the effect of full night illumination, partial night illumination and dark night on the transcriptomic profiles of captive zebrafinches.