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.

Exposure Effects of Environmentally Relevant Concentrations of the Tricyclic Antidepressant Amitriptyline in Early Life Stage Zebrafish

“…The behavioral end points we measured, however, were only affected at AMI concentrations several orders of magnitude above those measured in surface waters questioning the likelihood that current environmental concentrations of AMI are, by themselves, sufficient to induce any harmful impacts for fish in the natural environment. It should be recognised that a limitation in our behavioral assessments is the possible influence of circadian rhythms that are receiving increasing attention for studies on pollution impacts on behaviors . We conducted the studies on behavior between 9 am and 7 pm, and although experimental conditions were randomized to minimize the influence of circadian rhythms, any potential impact of timing remains untested and unaccounted for in the statistical analysis.…”

“…It should be recognised that a limitation in our behavioral assessments is the possible influence of circadian rhythms that are receiving increasing attention for studies on pollution impacts on behaviors. 66 We conducted the studies on behavior between 9 am and 7 pm, and although experimental conditions were randomized to minimize the influence of circadian rhythms, any potential impact of timing remains untested and unaccounted for in the statistical analysis. This, in turn, may mask any potential influence of circadian rhythms that could have a bearing on the observed lack of behavioral response and implied low risk associated with exposure to this drug.…”

Timing Matters: Time of Day Impacts the Ergogenic Effects of Caffeine—A Narrative Review

“…Circadian rhythms are innate biological oscillations that repeat approximately every 24 h, with an average duration of 24.09 h for women and 24.19 h for men [61]. These rhythms encompass any internally driven process within an organism that responds to, or is influenced by, external environmental cues [62]. Regulated by the biological clock, circadian rhythms synchronize biological functions to occur optimally for an individual's health [63].…”