Effects Of Artificial Light Research Articles

Maltese Coastline Never Sleeps: The Effects of Artificial Light at Night (ALAN) on the Local Infralittoral Assemblages—A Case Study

Aside from the most notorious threats, the Mediterranean Sea faces novel and poorly explored impacts from artificial light at night (ALAN), which influences natural light–dark cycles and affects marine ecosystems. This study investigates the impact of ALAN on coastal infralittoral assemblages in Malta, where such effects remain unexplored. Using Baited Remote Underwater Videos (BRUVs), we examined the influence of different light intensities on species assemblages and behaviour at two sites: a light-polluted harbour and a darker reef area. Our findings reveal significant differences in fish community composition between light treatments and habitats. Among the 23,955 individuals recorded across multiple taxa, Boops boops accounted for 80% of observations. From our results, light intensity had a more substantial impact on community structure than habitat type, with species-specific responses to light. Predatory species such as Trachurus trachurus displayed increased activity under high-intensity white light, while Apogon imberbis and Serranus scriba were more abundant under red light, irrespective of habitat. These results underscore the role of ALAN in altering marine community dynamics and emphasise the need for sustainable management strategies to mitigate its impact on the biodiversity of the Mediterranean. This study provides initial empirical evidence of ALAN’s effects in Maltese waters, contributing to broader efforts to understand and manage light pollution in marine ecosystems.

The effects of artificial light at night on spider brains.

Artificial light at night (ALAN) is an increasingly pervasive pollutant that alters animal behaviour and physiology, with cascading impacts on development and survival. Recent evidence links exposure to ALAN with neural damage, potentially due to its action on melatonin synthesis, a powerful antioxidant. However, these data are scarce and taxonomically limited. Here, we used micro-CT to test the effects of short-term ALAN exposure on brain volumes in the Australian garden orb-weaving spider (Hortophora biapicata), a species commonly found in urban areas and, specifically, around street lights. We found that short-term ALAN exposure was linked to reductions in the volumes of brain structures in the primary eye visual pathway, potentially as a consequence of oxidative stress or plastic shifts in neural investment. Although the effects of ALAN were subtle, they provided new insights into potential mechanisms underpinning the behavioural and physiological impacts of ALAN in this important urban predator.

Bright and early: artificial light affects arrival time, but not group size or vigilance in Little Penguins (Eudyptula minor)

Coastal developments are ever‐expanding and increasing the use of artificial lights within marine environments. Yet there is conflicting research on the impact of artificial lights on seabirds. Here, we experimentally investigated the impacts of artificial white lights on the behaviours (arrival time, group size, number of groups and vigilance) of breeding Little Penguins Eudyptula minor. Little Penguins are central‐place foragers that spend daylight hours foraging at sea and return to their breeding colony after sunset to attend to their chicks or relieve their incubating partners. We exposed Little Penguins returning to their colony at night to either (1) a self‐sustaining white LED floodlight or (2) a control system with a decoy light turned ‘off’. We used two different landing sites (site 1, site 2) that differed in landscape characteristics to assess whether behavioural responses to light were site‐specific. Little Penguins arrived in larger groups at the landing site 2. Regardless of site, we observed fewer groups that arrived earlier when the light was ‘on’. The effects of artificial light (or ‘lack of artificial light’) on the vigilance of Little Penguins were site‐specific, with Little Penguins spending proportionally more time in vigilance when the light was ‘off’ at site 2 compared with site 1. Our results support the idea that artificial lights produced from coastal developments can alter penguin behaviours, but that the effects of artificial lights can be context‐dependent and need to be assessed on a case‐by‐case basis.

Transcriptome Analysis on the ALAN-Induced Zebrafish Ovary: Desynchronization of Life Processes and Initiation of Diseases

Objective: The effect of artificial light at night (ALAN) on “transcriptome” is prominent owing to its capacity for “desynchronization” of organismal physiology. Light influences the circadian rhythm. This study aims to explore the ALAN-induced ovarian transcriptome of zebrafish for desynchronization of life processes. Methods: Four experimental conditions were set up for female zebrafish: one normal 12-hour light and 12-hour dark (LD) cycle, and three continuous exposures to ALAN for one week (LLW), one month (LLM), and one year (LLY). The whole transcriptome data analysis of the ALAN-exposed samples was then compared with the normal sample using RNA-Seq, followed by exploratory analyses. Results: The analysis revealed two different patterns of expression of genes where LLW and LLM differ with LLY samples in comparison to LD. Compared to LD, downregulation of the predicted hub genes was observed in all treatments; ribosome and oxidative phosphorylation pathways were enriched. LLY vs. LD contrast depicts the enrichment of three more pathways—RNA polymerase, adhesion junction, and signaling. The gene ontology (GO) enrichment portrays more prevalent biological processes in LLW vs. LD and LLM vs. LD than in LLY vs. LD. Contrast-wise disease annotation represents neoplasms as the most prevalent; disease enrichment denotes the major class of neoplasm, carcinoma, coupled with intellectual disability, global developmental delay, and seizures. Conclusion: Our study displayed desynchronization of various genes and pathways leading to the initiation of diseases, for the first time in zebrafish. Even though, this data shows that ALAN is a serious threat, further research is needed to determine the intensity and the duration of ALAN which might cause potential repercussions.

The Effects of Light on Sleep Patterns and Circadian Rhythms

Although humans spend an increasingly considerable amount of time in front of light emitting diode (LED)/digital screens, little research has been conducted focusing on the effects of artificial light on circadian rhythm and sleep. A current theory suggests that exposure to light, artificial or natural, outside of daytime hours has a detrimental effect on the neurobiology of an individual. Furthermore, artificial light from these screens or at a larger scale, light pollution, defined as excessive outdoor artificial light, can affect the circadian rhythms. The central pacemaker in the brain, known as the suprachiasmatic nucleus (SCN) controls various essential biological processes. Current evidence suggests different wavelengths of light have contrasting impacts on SCN activity and subsequent circadian rhythms. Alterations to circadian rhythms can have a profound impact on sleep and mood. Therefore, understanding how artificial light impacts SCN function is critical for determining the psychological and biological consequences. This paper reviews the effects that artificial light has on the brain, and breaks down the biological and psychological processes that control sleep and mood.

Preliminary Study on the Effect of Artificial Lighting on the Production of Basil, Mustard, and Red Cabbage Seedlings

Preliminary Study on the Effect of Artificial Lighting on the Production of Basil, Mustard, and Red Cabbage Seedlings

The Effect of the Daily Light Integral and Spectrum on Mesembryanthemum crystallinum L. in an Indoor Plant Production Environment

The effect of artificial lighting with different light spectra and photoperiods/daily light integrals (DLIs) on the yield, bioactive compounds and antioxidant capacity of the common ice plant (Mesembryanthemum crystallinum) was studied. Four-week-old seedlings were selected and subjected to four different light spectra made up of different combinations of blue (400–500 nm), green (500–600 nm) and red light (600–700 nm), with a total photosynthetic photon flux density (PPFD) of 180 µmol.m−2.s−1. Concurrently, the effect of the daily light integral (DLI) was also studied, with the light treatment photoperiod set at 18 h and 21 h. Biometric parameters such as fresh mass weight, leaf area, leaf width, and dry mass, together with plant metabolite contents such as total antioxidant capacity (TAC), vitamin C, chlorophyll a and b content, and total carotenoids and nitrates, were investigated. It was found that the plants grew better when exposed to light with a higher proportion of the red and blue spectrum, with the highest fresh mass of 68 g observed at a photoperiod of 18 h. On the other hand, green spectrum light was not found to yield any significant improvement in shoot weight, leaf area, or leaf size. It was also found that dry mass, chlorophyll b and nitrates were not influenced by the light spectrum but were influenced by the photoperiod duration. While both the dry mass and nitrate content increase as the photoperiod increases, a longer photoperiod had a negative effect on chlorophyll a, chlorophyll b and total carotenoids, with their content decreasing by as much 29% for chlorophyll a, 59% for chlorophyll b and 29% for total carotenoids. TAC content was seen to increase by more than 24% under the influence of 66% more green light, and 38% more under the 21 h photoperiod.

The effect of artificial light at night (ALAN) on the characteristics of diapause of Aedes albopictus

BackgroundRecently, the effect of artificial light at night (ALAN) on the physiology and behavior of insects has gradually attracted the attention of researchers and has become a new research topic. Aedes albopictus is an important vector that poses a great public health risk. Further studies on the diapause of Ae. albopictus can provide a basis for new vector control, and it is also worth exploring whether the effect of ALAN on the diapause of Ae. albopictus will provide a reference for the prevention and control of infectious diseases mediated by Ae. albopictus. MethodsIn this study, we experimentally studied the diapause characteristics of different geographical strains of Ae. albopictus under the interference of ALAN, explored the effect of ALAN on the diapause of Ae. albopictus and explored the molecular mechanism of ALAN on the diapause process through RNA-seq. ResultsAs seen from the diapause incidence, Ae. albopictus of the same geographic strain showed a lower diapause incidence when exposed to ALAN. The differentially expressed genes (DEGs) were mainly enriched in signaling and metabolism-related pathways in the parental females and diapause eggs of the ALAN group. ConclusionsALAN inhibits Ae. albopictus diapause. In the short photoperiod induced diapause of Ae. albopictus in temperate strain Beijing and subtropical strain Guangzhou, the disturbance of ALAN reduced the egg diapause rate and increased the egg hatching rate of Ae. albopictus, and the disturbance of ALAN also shortened the life cycle of Ae. albopictus eggs after hatching.

The effect of artificial light at night on a nocturnalprimate.

Anthropogenic disturbance is a major threat to biodiversity. An anthropogenic disturbance that is rarely addressed for nonhuman primates is the effect of artificial light at night (ALAN) which is defined by the spread of artificial lighting at night which eliminates natural darkness. Artificial light at night can result from streetlights, or indirectly from sky glow (artificial light that is scattered and reflected back to earth by the atmosphere). Research has demonstrated that artificial lighting causes changes in animal behavior, reproductive success, survivorship, as well as can alter the composition of the communities. The goal of this paper is to explore how the behavior of spectral tarsiers, Tarsius spectrumgurskyae, is modified in response to artificial light. We conducted this study at Tangkoko Nature Reserve on the easternmost tip of the northern arm of Sulawesi, Indonesia. The results of this study suggest that in response to artificial light tarsiers increase their time spent travelling and foraging, left their sleeping sites earlier and returned to them later thereby extending their daily activity time. The tarsiers also left their sleeping trees at lower heights, gave fewer vocalizations and fewer alarm calls each night in response to the additional artificial light. The tarsier's lengthened night might be leading to a change in interspecific competition for food as well as increase the ability of potential predators to locate the tarsiers. Additional research on the effect of ALAN on primates is clearly needed.

Effects of artificial light on the arrival time, duration of stay, and departure time of nocturnal flying insects

AbstractInsects with positive phototaxis fly to artificial light sources at night, stay there for a certain amount of time, and then fly away. Although many studies have been conducted on the arrival time of flying insects at artificial light sources, little is known about the time at which they fly away (departure time), duration of stay, and staying time zone. This information is important to protect phototactic insects from the fatal attraction to light that is known as a serious ecological light pollution. In this study, we aimed to identify the duration of stay and staying time zone for various insect species by marking them with light traps. Among the 63 species belonging to 11 orders observed at the study site, cluster analysis focused on 27 species for which 5 or more data points were obtained, highlighting three predominant stay patterns. Type 1 species arrived approximately 1.3 h and flew away approximately 4.1 h after sunset and stayed for a short period of approximately 2.6 h. Type 2 species arrived at approximately 1.2 h and flew away for approximately 9.6 h, with an 8.4 h stay. Type 3 species arrived later than Types 1 and 2, were attracted for 5.4 h, and flew away approximately 13.5 h with an 8.2 h stay. These results suggest that conservation biological countermeasures against light-attracted flying insects need to consider the stay patterns of insects that remain under outdoor lighting.

The effects of artificial light at night (ALAN) on the circadian biology of marine animals

The effects of artificial light at night (ALAN) on the circadian biology of marine animals

Artificial light at night affects fish passage rates in two small‐sized Cypriniformes fish

AbstractAn increasing presence of instream structures such as weirs, dams, culverts and reservoirs degrades habitats, fragments rivers and blocks fish movements worldwide. Longitudinal river movements are fundamental for many fish species and the most widespread solution to restore longitudinal connectivity is the implementation of different fish passage solutions. Fishway functionality, however, is highly variable. To design a functional fishway, several aspects of the fish's interaction with its environment need to be taken into consideration. Artificial light at night (ALAN) can affect a range of different behaviours in fish, from activity and movement to feeding and predator–prey relationships. In a fish passage setting, fish are exposed to artificial light at night (ALAN) in the form of light pollution, but, sometimes, also as part of the fish passage solution. Although likely highly species specific, the effect of artificial light on fish passage behaviour has been little explored. Here we study the passage behaviour of two small‐sized fish species, European gudgeon (Gobio gobio) and Italian riffle dace (Telestes muticellus), over a scaled deep side notch weir in a hydraulic flume in three different light conditions: daylight, darkness and ALAN. Although both species passed the obstacle at high efficiencies under all light conditions, their passage behaviours were influenced by light, particularly at the higher levels. While ALAN reduced passage success and resulted in delayed passage for gudgeon, riffle dace passed at higher rates under the artificial light compared to night treatment. Both results indicate a risk of negative effects from ALAN on passage performance at real fishways—or movement rates in lit areas of natural streams—for both species. Independent of light conditions, individuals of both species also passed faster after repeated trials, demonstrating learning in a fish passage context.

The effect of artificial light at night on wild fish community: manipulative field experiment and species composition analysis using environmental DNA

The use of artificial light at night (ALAN) has been increasing globally and has been reported to affect a wide range of organisms. However, the effects of ALAN on wild fish communities remain unknown. In this study, we investigated the effects of ALAN on the species distribution and composition of a fish community in a canal. We hypothesized that the fish species composition in areas subjected to ALAN would differ from that in the control area. To test this hypothesis, we conducted a three-week manipulative field experiment in which real-world ALAN conditions were simulated by illuminating the water surface at night using LED lights for two weeks. During the experiment, water samples were collected from ALAN and control conditions four times a week, from which environmental DNA (eDNA) were extracted. Additionally, the number of arthropods in the ALAN and control environments was recorded daily to investigate whether ALAN impacts distribution patterns of fish prey, which may have indirect effect on fish through changed prey-predator relationships. Collected water samples were analyzed using eDNA metabarcoding with MiFish primers and real-time PCR targeting six fish species to obtain qualitative and quantitative data on fish species composition. We compared the fish species composition data between the ALAN and control environments. Our results suggest that ALAN did not significantly influence the overall fish species composition and that the sampling location had a more significant impact. Our findings also point to the possibility that the effect of ALAN on habitat selection may vary depending on the diet of the individual fish. Overall, the effect of ALAN on fish was less significant than expected. By combining eDNA methods with manipulative field experiment, this study shows the applicability of eDNA methods in investigating the effect of pollutants and offers a promising area for future investigation.

The effects of artificial light at night on behavioral rhythm and related gene expression are wavelength dependent in the oyster Crassostrea gigas.

Artificial light at night (ALAN) constitutes a growing threat to coastal ecosystems by altering natural light cycles, which could impair organisms' biological rhythms, with resulting physiological and ecological consequences. Coastal ecosystems are strongly exposed to ALAN, but its effects on coastal organisms are poorly studied. Besides ALAN's intensity, ALAN's quality exposure may change the impacts on organisms. This study aims to characterize the effects of different ALAN's spectral compositions (monochromatic wavelength lights in red (peak at 626nm), green (peak at 515nm), blue (peak at 467nm), and white (410-680nm) light) at low and realistic intensity (1lx) on the oyster Crassostrea gigas daily rhythm. Results reveal that all ALAN's treatments affect the oysters' daily valve activity rhythm in different manners and the overall expression of the 13 studied genes. Eight of these genes are involved in the oyster's circadian clock, 2 are clock-associated genes, and 3 are light perception genes. The blue light has the most important effects on oysters' valve behavior and clock and clock-associated gene expression. Interestingly, red and green lights also show significant impacts on the daily rhythm, while the lowest impacts are shown with the green light. Finally, ALAN white light shows the same impact as the blue one in terms of loss of rhythmic oysters' percentage, but the chronobiological parameters of the remaining rhythmic oysters are less disrupted than when exposed to each of the monochromatic light's treatments alone. We conclude that ALAN's spectral composition does influence its effect on oysters' daily rhythm, which could give clues to limit physiological and ecological impacts on coastal environments.

Effects of artificial light at night and drought on the photosynthesis and physiological traits of two urban plants.

Urban plants are currently confronted with the stresses posed by artificial light at night (ALAN) and drought. A field block experiment was designed to explore the potential effects of ALAN and drought on the photosynthesis and physiological characters of two common urban plants, Euonymus japonicus (E. japonicus) and Rosa hybrida (R. hybrida). Each plant species was subjected to four distinct treatments: neither ALAN nor drought, ALAN, drought, and both ALAN and drought. The result showed the following: (1) ALAN significantly reduced the effective quantum yield (ΦPSII), apparent electron transfer rate (ETR), photochemical quenching parameter (qp), net photosynthetic (Pn), stomatal conductance (Gs), stomatal limit value (Ls), and the pigment concentrations and remarkably increased the content of malondialdehyde (MDA), total antioxidant capacity (TAC), and starch in both E. japonicus and R. hybrida. Furthermore, ALAN increased the soluble saccharides of E. japonicus, and this effect of ALAN also occurred on R. hybrida under drought. (2) Drought significantly decreased the ΦPSII, ETR, qp, Pn, Gs, Ls, and the pigment concentrations and remarkably increased the content of MDA and TAC for both E. japonicus and R. hybrida. Moreover, drought did not significantly change the starch content of both species, and it significantly increased the content of soluble saccharides for E. japonicus. (3) The interaction between ALAN and drought occurred on the ΦPSII, ETR, Pn, MDA, and TAC of E. japonicus, but had no effect on R. hybrida. For urban areas affected by ALAN and drought, it is advisable to select plant species with strong stress resistance for gardening purposes, and plants directly exposed to ALAN should receive sufficient water during hot and dry weather conditions to maintain their normal growth.

Coastal developments and Sea turtle conservation: Effect of artificial light on female nesting behaviours and hatchling post-emergence migrations

No abstract available

Effects of artificial light at night on the mobility of the sea urchin Paracentrotus lividus

Light pollution poses a significant global threat to biodiversity, driven by the increasing coastal urbanization and the resulting growth of artificial light at night (ALAN). However, to date, the scientific community has focused mainly on studying its ecological effects within the terrestrial environment. It is only recently that attention has turned to coastal marine systems which are crucial due to their essential contribution at the ecosystem level. These environments, characterized by their high productivity, also play a crucial role in protecting coasts against erosion. The aim of this case study was to investigate the possible effects of ALAN on the sea urchin species Paracentrotus lividus in four areas of an Italian rocky coast, selected according to a gradient of light intensity (0, 0.4, 3 and 25 lux), from April 2022 to February 2023. Effects of ALAN were examined by measuring the density and size of sea urchins and also their reactivity to a stress condition through an innovative technique of overturning sea urchins to study their physiological response in the presence or absence of artificial light. In addition, the permanence of sea urchins in the four areas was evaluated through an efficient tagging test. Results show how these organisms, typically nocturnal, suffer negative effects of ALAN in terms of minor density and mobility, expressed as the speed of response to an adverse event, compared to a dark area.

Artificial light at night increases the nighttime feeding of monarch butterfly caterpillars without affecting host plant quality

Most research on the effects of artificial light at night (ALAN) on animal behaviour focuses on nocturnal species. In addition, there are few studies on the effects of ALAN on the feeding behaviour of herbivores or how such behavioural changes affect herbivore performance. In this study, we tested whether ALAN has direct effects on the feeding frequency and performance of the larvae of the monarch butterfly (Danaus plexippus), a species in which adults are diurnal but larvae exhibit little diel rhythm in feeding activity. We also tested for effects of ALAN on the growth, nutritional quality, or anti-herbivore defences of this herbivore's primary host plant in North America, common milkweed (Asclepias syriaca). There was no evidence that ALAN affected the growth, nutritional quality or defensive traits of the host plant. However, at night, the feeding frequency of larvae exposed to ALAN was two times higher than in larvae that were not exposed to ALAN. Despite this effect on feeding frequency, ALAN had no significant effects on larval development time (days from second instar to pupation) or pupal mass. Our study highlights that ALAN can have strong impacts on the feeding activity patterns of herbivorous insects and that these impacts are not limited to nocturnal species.

Effect of artificial light on the lipid oxidation of whole, cooked Northern shrimp (Pandalus borealis) during frozen storage

In retail, whole, cooked Northern shrimp (Pandalus borealis) is commonly stored in illuminated display freezers for an extended time period. The aim of the present study was to understand how and when light-induced lipid oxidation occurs. Two sizes of cooked shrimp were packed in air and stored frozen with and without artificial light for 84 days. Samples were investigated for oxidative stability (peroxide value (PV), volatile compounds, and tocopherol consumption) and color changes and free astaxanthin.PV only increased significantly for shrimp stored with light (up to 20 meq/kg). α-tocopherol content remained unchanged during the storage period irrespective of the storage condition. Shrimp stored with light showed an increased L*-value and decreased a* and b*-values, whereas these color values did not change significantly in shrimp stored in darkness. The color changes could not be explained by changes in the free astaxanthin content as no significant changes occurred in free astaxanthin content during storage. The formation of volatile compounds depended on the shrimp size and light exposure, but the concentration of e.g. 2-methylbutanal, 3-methylbutanal and 1-penten-3-ol increased significantly more in shrimp stored in light than when they were stored without light. In conclusion, illuminated storage increased lipid oxidation in Northern shrimp.

The effects of artificial light at night on the foraging activity of Japanese eels: implications of recreational fishing data

The effects of artificial light at night on the foraging activity of Japanese eels: implications of recreational fishing data