Colwell, C. S. (2016). Circadian Rhythms: Does Burning the Midnight Oil Leave You Weak? Curr Biol, 26(14), R669–71.
Abstract: A new study shows that nocturnal light exposure rapidly disrupts the central circadian clock as well as reduces motor performance and bone health. These findings provide a striking example of the costs of living in a disrupted light/dark cycle.
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Bennie, J., Davies, T. W., Cruse, D., & Gaston, K. J. (2016). Ecological effects of artificial light at night on wild plants. J Ecol, 104(3), 611–620.
Abstract: 1.Plants use light as a source of both energy and information. Plant physiological responses to light, and interactions between plants and animals (such as herbivory and pollination), have evolved under a more or less stable regime of 24-hour cycles of light and darkness, and, outside of the tropics, seasonal variation in daylength.
2.The rapid spread of outdoor electric lighting across the globe over the past century has caused an unprecedented disruption to these natural light cycles. Artificial light is widespread in the environment, varying in intensity by several orders of magnitude from faint skyglow reflected from distant cities to direct illumination of urban and suburban vegetation.
3.In many cases artificial light in the nighttime environment is sufficiently bright to induce a physiological response in plants, affecting their phenology, growth form and resource allocation. The physiology, behaviour and ecology of herbivores and pollinators is also likely to be impacted by artificial light. Thus, understanding the ecological consequences of artificial light at night is critical to determine the full impact of human activity on ecosystems.
4.Synthesis. Understanding the impacts of artificial nighttime light on wild plants and natural vegetation requires linking the knowledge gained from over a century of experimental research on the impacts of light on plants in the laboratory and greenhouse with knowledge of the intensity, spatial distribution, spectral composition and timing of light in the nighttime environment. To understand fully the extent of these impacts requires conceptual models that can (i) characterise the highly heterogeneous nature of the nighttime light environment at a scale relevant to plant physiology, and (ii) scale physiological responses to predict impacts at the level of the whole plant, population, community and ecosystem.
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Aulsebrook, A. E., Jones, T. M., Rattenborg, N. C., Roth, T. C. 2nd, & Lesku, J. A. (2016). Sleep Ecophysiology: Integrating Neuroscience and Ecology. Trends Ecol Evol, 31(8), 590–599.
Abstract: Here, we propose an original approach to explain one of the great unresolved questions in animal biology: what is the function of sleep? Existing ecological and neurological approaches to this question have become roadblocks to an answer. Ecologists typically treat sleep as a simple behavior, instead of a heterogeneous neurophysiological state, while neuroscientists generally fail to appreciate the critical insights offered by the consideration of ecology and evolutionary history. Redressing these shortfalls requires cross-disciplinary integration. By bringing together aspects of behavioral ecology, evolution, and conservation with neurophysiology, we can achieve a more comprehensive understanding of sleep, including its implications for adaptive waking behavior and fitness.
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Stevens, R. G. (2016). Circadian disruption and health: Shift work as a harbinger of the toll taken by electric lighting. Chronobiol Int, 33(6), 589–594.
Abstract: Electric light is one of the signature inventions of human beings. A problem, however, is that electric light can confuse our endogenous circadian rhythmicity. It has now become apparent that circadian biology is fundamental to the functioning and adaptation of almost all life forms. In the modern world, everyone is exposed to electric light during the day and night, and thereby can experience some level of circadian disruption. Perhaps as a canary in the coal mine, study of people whose work hours include nighttime (shift workers) is beginning to yield insights on the adverse health effects of circadian disruption from electric light.
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Son, K. - H., Jeon, Y. - M., & Oh, M. - M. (2016). Application of supplementary white and pulsed light-emitting diodes to lettuce grown in a plant factory with artificial lighting. Hortic. Environ. Biotechnol., 57(6), 560–572.
Abstract: Light-emitting diodes (LEDs) are currently undergoing rapid development as plant growth light sources in a plant factory with artificial lighting (PFAL). However, little is known about the effects of supplementary light and pulsed LEDs on plant growth, bioactive compound productions, and energy efficiency in lettuce. In this study, we aimed to determine the effects of supplementary white LEDs (study I) and pulsed LEDs (study II) on red leaf lettuce (Lactuca sativa L. ‘Sunmang’). In study I, six LED sources were used to determine the effects of supplementary white LEDs (RGB 7:1:1, 7:1:2, RWB 7:1:2, 7:2:1, 8:1:1, 8:2:0 [based on chip number] on lettuce). Fluorescent lamps were used as the control. In study II, pulsed RWB 7:2:1 LED treatments (30, 10, 1 kHz with a 50 or 75% duty ratio) were applied to lettuce. In study I, the application of red and blue fractions improved plant growth characteristics and the accumulation of antioxidant phenolic compounds, respectively. In addition, the application of green light increased plant growth, including the fresh and dry weights of shoots and roots, as well as leaf area. However, the substitution of green LEDs with white LEDs induced approximately 3.4-times higher light and energy use efficiency. In study II, the growth characteristics and photosynthesis of lettuce were affected by various combinations of duty ratio and frequency. In particular, biomass under a 1 kHz 75% duty ratio of pulsed LEDs was not significantly different from that of the control (continuous LEDs). Moreover, no significant difference in leaf photosynthetic rate was observed between any pulsed LED treatment utilizing a 75% duty ratio versus continuous LEDs. However, some pulsed LED treatments may potentially improve light and energy use efficiency compared to continuous LEDs. These results suggest that the fraction of red, blue, and green wavelengths of LEDs is an important factor for plant growth and the biosynthesis of bioactive compounds in lettuce and that supplementary white LEDs (based on a combination of red and blue LEDs) might be more suitable as a commercial lighting source than green LEDs. In addition, the use of suitable pulses of LEDs might save energy while inducing plant growth similar to that under continuous LEDs. Our findings provide important basic information for designing optimal light sources for use in a PFAL.
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