Time is of the essence: The importance of considering biological rhythms in an increasingly polluted world

Abstract

Biological rhythms have a crucial role in shaping the biology and ecology of organisms. Light pollution is known to disrupt these rhythms, and evidence is emerging that chemical pollutants can cause similar disruption. Conversely, biological rhythms can influence the effects and toxicity of chemicals. Thus, by drawing insights from the extensive study of biological rhythms in biomedical and light pollution research, we can greatly improve our understanding of chemical pollution. This Essay advocates for the integration of biological rhythmicity into chemical pollution research to gain a more comprehensive understanding of how chemical pollutants affect wildlife and ecosystems. Despite historical barriers, recent experimental and technological advancements now facilitate the integration of biological rhythms into ecotoxicology, offering unprecedented, high-resolution data across spatiotemporal scales. Recognizing the importance of biological rhythms will be essential for understanding, predicting, and mitigating the complex ecological repercussions of chemical pollution.

Fig 1. Biological rhythms synchronize the biology of organisms with periodic changes in the abiotic environment.

(A) Environmental cycles such as seasonality, the lunar cycle, the day–night cycle, and tidal activity are characterized by periodic changes in, among other things, light, temperature, salinity, and oxygen availability. (B) Biological rhythms manage the biosphere. They occur across the tree of life and manifest across all levels of biological organization.

Fig 2. Examples of how pollution can intersect with biological rhythms.

Despite having received relatively little research attention to date, the few studies that have tested for potential interactions between chemical pollution exposure and biological rhythms have demonstrated that these factors can interact at various spatiotemporal scales and in diverse biological systems (A-C). While our focus is on chemical pollution research, chronobiology is clearly relevant to all forms of environmental change (e.g., light pollution, D).

Fig 3. Illustration of the reciprocal relationship between chemical pollutants and biological rhythms.

Chemical pollutants can disrupt biological rhythms, and, conversely, biological rhythms can influence an organism’s susceptibility and/or response to chemicals. The example presented here is one of many possible scenarios and is used for illustrative purposes.