scholarly journals The Endosymbiotic Coral Algae Symbiodiniaceae Are Sensitive to a Sensory Pollutant: Artificial Light at Night, ALAN

2021 ◽  
Vol 12 ◽  
Author(s):  
Inbal Ayalon ◽  
Jennifer I. C. Benichou ◽  
Dror Avisar ◽  
Oren Levy
Keyword(s):  
Cell Cultures ◽  
Marine Ecosystem ◽  
Photochemical Quenching ◽  
Artificial Light ◽  
Light At Night ◽  
Symbiotic Algae ◽  
Light Spectra ◽  
Clade C ◽  
Low Levels ◽  
Non Photochemical Quenching

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.

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

SLEEP ◽  
2019 ◽  
Vol 42 (Supplement_1) ◽  
pp. A15-A16 ◽  
Author(s):  
Jesse W Mindel ◽  
Samantha L Rojas ◽  
David Kline ◽  
Shengying Bao ◽  
Ali Rezai ◽  
...  
Keyword(s):  
Systemic Inflammation ◽  
Artificial Light ◽  
Light At Night ◽  
Low Levels

scholarly journals Transcriptional regulation of photoprotection in dark-to-light transition - more than just a matter of excess light energy

2021 ◽  
Author(s):  
Petra Redekop ◽  
Emanuel Sanz-Luque ◽  
Yizhong Yuan ◽  
Gaelle Villain ◽  
Dimitris Petroutsos ◽  
...  
Keyword(s):  
Light Intensity ◽  
Photosynthetic Electron Transport ◽  
Time Of Day ◽  
Photochemical Quenching ◽  
Mrna Accumulation ◽  
Photosynthetic Organisms ◽  
Light Spectra ◽  
Excess Light ◽  
Non Photochemical Quenching ◽  
The Impact

In nature, photosynthetic organisms are exposed to different light spectra and intensities depending on the time of day and atmospheric and environmental conditions. When photosynthetic cells absorb excess light, they induce non-photochemical quenching to avoid photo-damage and trigger expression of photoprotective genes. In this work, we used the green alga Chlamydomonas reinhardtii to assess the impact of light intensity, light quality, wavelength, photosynthetic electron transport and CO2 on induction of the photoprotective genes (LHCSR1, LHCSR3 and PSBS) during dark-to-light transitions. Induction (mRNA accumulation) occurred at very low light intensity, was independently modulated by blue and UV-B radiation through specific photoreceptors, and only LHCSR3 was strongly controlled by CO2 levels through a putative enhancer function of CIA5, a transcription factor that controls genes of the carbon concentrating mechanism. We propose a model that integrates inputs of independent signaling pathways and how they may help the cells anticipate diel conditions and survive in a dynamic light environment.

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

2018 ◽  
Vol 28 (15) ◽  
pp. 2474-2478.e3 ◽  
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

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

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.

scholarly journals Short-term effects of heavy metal and temperature stresses on the photophysiology of Symbiodinium isolated from the coral Fungia repanda

Ocean Life ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 11-20 ◽  
Author(s):  
MANJULA D. GHOORA ◽  
SIVAJYODEE S. PILLY ◽  
PRAMOD KUMAR CHUMUN ◽  
SHOBHA JAWAHEER ◽  
RANJEET BHAGOOLI
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Photosynthetic Capacity ◽  
Pulse Amplitude ◽  
Photochemical Quenching ◽  
Short Term ◽  
Temperature Stresses ◽  
Clade C ◽  
Non Photochemical Quenching ◽  
Short Term Effects

Ghoora MD, Pilly SS, Chumun PK, Jawaheer S, Bhagooli R. 2017. Short-term effects of heavy metal and temperature stresses on the photo-physiology of Symbiodinium isolated from the coral Fungia repanda. Ocean Life 1: 11-20. This study aimed to investigate the effects of the heavy metals, copper, zinc and lead, on the photo-physiology of the symbiotic dinoflagellate Symbiodinium isolated from the coral Fungia repanda. Freshly isolated Symbiodinium found to belong to clade C were exposed to different concentrations of the three heavy metals for 3-hour and 18-hour treatments at 28°C and 32°C. The Pulse Amplitude Modulated (PAM) fluorometry technique was used to determine the maximum quantum yield (Fv/Fm), relative maximum electron transport rate (rETRmax) and maximum non-photochemical quenching (NPQmax) of the photosystem II (PSII). An increase in non-photochemical quenching accompanied by a decrease in photosynthetic capacity was noted for copper at a concentration of 50 µg/L for both temperatures. The Fv/Fm was not significantly affected by the Zn treatments. However, at 28 °C, isolates treated with 100 µg/L Zn for 18 hours showed an increase in non-photochemical quenching accompanied by a decrease in photosynthetic capacity. Pb had the most profound effect on all of the isolates. The Fv/Fm significantly decreased and an increase in NPQmax was noted. The decrease of rETRmax and increase in NPQmax for the heavy metal bioassays under 32 °C were more significant than at 28 °C. This study suggests that Cu (≥50 µg/L), Zn (≥ 100 µg/L) and Pb decrease the photosynthetic capacity of the Symbiodinium isolates from F. repanda especially more so with increasing temperatures.

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

2018 ◽  
Vol 285 (1875) ◽  
pp. 20172751 ◽  
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.

scholarly journals Artificial light at night causes reproductive failure in clownfish

2019 ◽  
Vol 15 (7) ◽  
pp. 20190272 ◽  
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.

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

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.

Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541a-541
Author(s):  
Lailiang Cheng ◽  
Leslie H. Fuchigami ◽  
Patrick J. Breen
Keyword(s):  
High Light ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Psii Efficiency ◽  
Fluorescence Measurements ◽  
Free Radical Formation ◽  
Highly Correlated ◽  
Non Photochemical Quenching ◽  
Leaf N

Bench-grafted Fuji/M26 apple trees were fertigated with different concentrations of nitrogen by using a modified Hoagland solution for 6 weeks, resulting in a range of leaf N from 1.0 to 4.3 g·m–2. Over this range, leaf absorptance increased curvilinearly from 75% to 92.5%. Under high light conditions (1500 (mol·m–2·s–1), the amount of absorbed light in excess of that required to saturate CO2 assimilation decreased with increasing leaf N. Chlorophyll fluorescence measurements revealed that the maximum photosystem II (PSII) efficiency of dark-adapted leaves was relatively constant over the leaf N range except for a slight drop at the lower end. As leaf N increased, non-photochemical quenching under high light declined and there was a corresponding increase in the efficiency with which the absorbed photons were delivered to open PSII centers. Photochemical quenching coefficient decreased significantly at the lower end of the leaf N range. Actual PSII efficiency increased curvilinearly with increasing leaf N, and was highly correlated with light-saturated CO2 assimilation. The fraction of absorbed light potentially used for free radical formation was estimated to be about 10% regardless of the leaf N status. It was concluded that increased thermal dissipation protected leaves from photo-oxidation as leaf N declined.

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