0038 Sleeping with Low Levels of Artificial Light at Night Increases Systemic Inflammation in Humans

Artificial Light at Night, ALAN, is a major emerging issue in biodiversity conservation, which can negatively impact both terrestrial and marine environments. Therefore, it should be taken into serious consideration in strategic planning for urban development. While the lion’s share of research has dealt with terrestrial organisms, only a handful of studies have focused on the marine milieu. To determine if ALAN impacts the coral reef symbiotic algae, that are fundamental for sustainable coral reefs, we conducted a short experiment over a period of one-month by illuminating isolated Symbiodiniaceae cell cultures from the genera Cladocopium (formerly Clade C) and Durusdinium (formerly Clade D) with LED light. Cell cultures were exposed nightly to ALAN levels of 0.15 μmol quanta m–2 s–1 (∼4–5 lux) with three light spectra: blue, yellow and white. Our findings showed that even in very low levels of light at night, the photo-physiology of the algae’s Electron Transport Rate (ETR), Non-Photochemical Quenching, (NPQ), total chlorophyll, and meiotic index presented significantly lower values under ALAN, primarily, but not exclusively, in Cladocopium cell cultures. The findings also showed that diverse Symbiodiniaceae types have different photo-physiology and photosynthesis performances under ALAN. We believe that our results sound an alarm for the probable detrimental effects of an increasing sensory pollutant, ALAN, on the eco-physiology of symbiotic corals. The results of this study point to the potential effects of ALAN on other organisms in marine ecosystem such as fish, zooplankton, and phytoplankton in which their biorhythms is entrained by natural light and dark cycles.

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Low Levels of Artificial Light at Night Strengthen Top-Down Control in Insect Food Web

Current Biology ◽

10.1016/j.cub.2018.05.078 ◽

2018 ◽

Vol 28 (15) ◽

pp. 2474-2478.e3 ◽

Cited By ~ 25

Author(s):

Dirk Sanders ◽

Rachel Kehoe ◽

Dave Cruse ◽

F.J. Frank van Veen ◽

Kevin J. Gaston

Keyword(s):

Food Web ◽

Artificial Light ◽

Top Down ◽

Light At Night ◽

Low Levels

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Large-scale deregulation of gene expression by artificial light at night in tadpoles of common toads

10.1101/2021.07.08.451570 ◽

2021 ◽

Author(s):

Morgane Touzot ◽

Tristan Lefebure ◽

Thierry Lengagne ◽

Jean Secondi ◽

Adeline Dumet ◽

...

Keyword(s):

Gene Expression ◽

Large Scale ◽

Bufo Bufo ◽

Artificial Light ◽

Light At Night ◽

Light Levels ◽

Immune Challenges ◽

Physiological Pathways ◽

Low Levels ◽

Dose Dependent

Artificial light at night (ALAN) affects numerous physiological and behavioural mechanisms in various species by potentially disturbing circadian timekeeping systems. Although gene-specific approaches have already shown the deleterious effect of ALAN on the circadian clock, immunity and reproduction, large-scale transcriptomic approaches with ecologically relevant light levels are still lacking to assess the global impact of ALAN on biological processes. Moreover, studies have focused mainly on variations in gene expression during the night in the presence of ALAN but never during the day. In a controlled laboratory experiment, transcriptome sequencing of Bufo bufo tadpoles revealed that ALAN affected gene expression at both night and daytime with a dose-dependent effect and globally induced a downregulation of genes. ALAN effects were detected at very low levels of illuminance (0.1 lux) and affected mainly genes related to the innate immune system and, to a lesser extend to lipid metabolism. These results indicate that a broad range of physiological pathways is impacted at the molecular level by very low levels of ALAN potentially resulting in reduced survival under environmental immune challenges.

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Artificial light at night shifts daily activity patterns but not the internal clock in the great tit ( Parus major )

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.2751 ◽

2018 ◽

Vol 285 (1875) ◽

pp. 20172751 ◽

Cited By ~ 11

Author(s):

Kamiel Spoelstra ◽

Irene Verhagen ◽

Davy Meijer ◽

Marcel E. Visser

Keyword(s):

Phase Shift ◽

Daily Activity ◽

Parus Major ◽

Internal Clock ◽

Circadian System ◽

Constant Darkness ◽

Artificial Light ◽

Light At Night ◽

Dim Light ◽

Low Levels

Artificial light at night has shown a dramatic increase over the last decades and continues to increase. Light at night can have strong effects on the behaviour and physiology of species, which includes changes in the daily timing of activity; a clear example is the advance in dawn song onset in songbirds by low levels of light at night. Although such effects are often referred to as changes in circadian timing, i.e. changes to the internal clock, two alternative mechanisms are possible. First, light at night can change the timing of clock controlled activity, without any change to the clock itself; e.g. by a change in the phase relation between the circadian clock and expression of activity. Second, changes in daily activity can be a direct response to light (‘masking’), without any involvement of the circadian system. Here, we studied whether the advance in onset of activity by dim light at night in great tits ( Parus major ) is indeed attributable to a phase shift of the internal clock. We entrained birds to a normal light/dark (LD) cycle with bright light during daytime and darkness at night, and to a comparable (LDim) schedule with dim light at night. The dim light at night strongly advanced the onset of activity of the birds. After at least six days in LD or LDim, we kept birds in constant darkness (DD) by leaving off all lights so birds would revert to their endogenous, circadian system controlled timing of activity. We found that the timing of onset in DD was not dependent on whether the birds were kept at LD or LDim before the measurement. Thus, the advance of activity under light at night is caused by a direct effect of light rather than a phase shift of the internal clock. This demonstrates that birds are capable of changing their daily activity to low levels of light at night directly, without the need to alter their internal clock.

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Artificial light at night causes reproductive failure in clownfish

Biology Letters ◽

10.1098/rsbl.2019.0272 ◽

2019 ◽

Vol 15 (7) ◽

pp. 20190272 ◽

Cited By ~ 8

Author(s):

Emily K. Fobert ◽

Karen Burke da Silva ◽

Stephen E. Swearer

Keyword(s):

Community Dynamics ◽

Terrestrial Ecosystems ◽

Reproductive Fitness ◽

Fertilization Success ◽

Artificial Light ◽

Light At Night ◽

Light Regimes ◽

In The Wild ◽

Low Levels ◽

Population And Community Dynamics

The Earth is getting brighter at night, as artificial light at night (ALAN) continues to increase and extend its reach. Despite recent recognition of the damaging impacts of ALAN on terrestrial ecosystems, research on ALAN in marine systems is comparatively lacking. To further our understanding of the impacts of ALAN on marine organisms, this study examines how the reproductive fitness of the common clownfish Amphiprion ocellaris is influenced by the presence of ALAN. We assessed how exposure to low levels of ALAN affects (i) frequency of spawning, (ii) egg fertilization success, and (iii) hatching success of A. ocellaris under control (12 : 12 day–night) and treatment (12 : 12 day–ALAN) light regimes. While we found exposure to ALAN had no impact on the frequency of spawning or fertilization success, ALAN had dramatic effects on hatching. Amphiprion ocellaris eggs incubated in the presence of ALAN simply did not hatch, resulting in zero survivorship of offspring. These findings suggest ALAN can significantly reduce reproductive fitness in a benthic-spawning reef fish. Further research in this field is necessary to fully understand the extent of this impact on population and community dynamics in the wild.

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Effects of Low-Level Artificial Light at Night on Kentucky Bluegrass and an Introduced Herbivore

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.732959 ◽

2021 ◽

Vol 9 ◽

Author(s):

Morgan C. Crump ◽

Cassandra Brown ◽

Robert J. Griffin-Nolan ◽

Lisa Angeloni ◽

Nathan P. Lemoine ◽

...

Keyword(s):

Poa Pratensis ◽

Single Species ◽

Kentucky Bluegrass ◽

Light Treatment ◽

Urban Environments ◽

Acheta Domesticus ◽

Artificial Light ◽

Light At Night ◽

Leaf Level ◽

Low Levels

Increasing evidence suggests that artificial light at night (ALAN) can negatively impact organisms. However, most studies examine the impacts of ALAN on a single species or under high levels of artificial light that are infrequent or unrealistic in urban environments. We currently have little information on how low levels of artificial light emanating from urban skyglow affect plants and their interactions with herbivores. We examined how short-term, low levels of ALAN affect grass and insects, including growth rate, photosynthesis, and stomatal conductance in grass, and foraging behavior and survival in crickets. We compared growth and leaf-level gas exchange of Kentucky Bluegrass (Poa pratensis) under low-levels of ALAN (0.3 lux) and starlight conditions (0.001 lux). Furthermore, each light treatment was divided into treatments with and without house crickets (Acheta domesticus). Without crickets present, bluegrass grown under ALAN for three weeks grew taller than plants grown under natural night light levels. In the fourth week when crickets were introduced, grass height decreased resulting in no measurable effects of light treatment. There were no measurable differences in grass physiology among treatments. Our results indicate that low levels of light resulting from skyglow affect plant growth initially. However, with herbivory, the effects of ALAN on grass may be inconsequential. Gaining an understanding of how ALAN affects plant-insect interactions is critical to predicting the ecological and evolutionary consequences of anthropogenic light pollution.

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The physical environment

10.1093/oso/9780198827238.003.0003 ◽

2018 ◽

Author(s):

Philip James

Keyword(s):

Physical Environment ◽

Urban Climate ◽

Urban Environments ◽

Artificial Light ◽

Noise Levels ◽

Light At Night ◽

High Noise ◽

P Elements ◽

Micro Organisms ◽

Diversity Of Life

Elements of the physical aspects of urban environments determine which micro-organisms, plants, and animals live in urban environments. In this chapter, climate, air, water, soil, noise, and light are discussed. Urban environments are affected by the climate of the region in which they are located, and in turn and create their own, distinctive urban climate. Air, water, and soil are all affected by urbanization. Pollution of these elements is common. High noise levels and artificial light at night (ALAN—a new phenomenon) are both strongly associated with urban environments. Details of both are discussed. The discussion in this chapter provides a foundation for further exploration of the diversity of life in urban environments and for later exploration of how organisms adapt to urban living, which will be discussed in Parts II and III.

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