Circadian rhythms and environmental disturbances ? underexplored interactions

Perjantai 24.8.2018 klo 9.24 - Mikko Nikinmaa

Variation of functions with daily cycles is an important component of environmental responses of organisms, and environmental disturbances can affect daily rhythms. This possibility has been surprisingly little taken into account in environmental studies. For this reason Jenni Prokkola and I have written a commentary on the topic. Its abstract follows:

Biological rhythms control the life of virtually all organisms, impacting numerous aspects ranging from subcellular processes to behaviour. Many studies have shown that changes in abiotic environmental conditions can disturb or entrain circadian (∼24 h) rhythms. These expected changes are so large that they could impose risks to the long-term viability of populations. Climate change is a major global stressor affecting the fitness of animals, partially because it challenges the adaptive associations between endogenous clocks and temperature – consequently, one can posit that a large-scale natural experiment on the plasticity of rhythm–temperature interactions is underway. Further risks are posed by chemical pollution and the depletion of oxygen levels in aquatic
environments. Here, we focused our attention on fish, which are at
heightened risk of being affected by human influence and are
adapted to diverse environments showing predictable changes in
light conditions, oxygen saturation and temperature. The examined
literature to date suggests an abundance of mechanisms that can
lead to interactions between responses to hypoxia, pollutants or
pathogens and regulation of endogenous rhythms, but also reveals
gaps in our understanding of the plasticity of endogenous rhythms in fish and in how these interactions may be disturbed by human
influence and affect natural populations. Here, we summarize
research on the molecular mechanisms behind environment–clock
interactions as they relate to oxygen variability, temperature and
responses to pollutants, and propose ways to address these
interactions more conclusively in future studies. (Source: Prokkola JM, Nikinmaa M, Journal of Experimental Biology 221, jeb179267)