Effect of Artificial Lighting on Amphibians
In general, amphibians often lose weight when their artificial lighting, such as street lamps, are too bright to find food, which leads to a decrease in population. (Fig.1)

Fig.1. Light in wetlands can suppress diel vertical migration of zooplankton and influence foraging behavior of amphibians.
Many aquatic invertebrates migrate up and down in wetlands during the course of a night and day. This “diel vertical migration” presumably results from a need to avoid predation during lighted conditions so many zooplankton forage near water surfaces only during dark conditions. (Moore et al)
Disruption of diel vertical migration by artificial lighting may have significant detrimental effects on ecosystem health. Moore et al. conclude that “vertical migration of lake grazers may contribute to enhanced concentrations of algae in both urban lakes and coastal waters. This condition, in turn, often results in deterioration of water quality”

Fig.2. Two tadpoles of the same age and kept in 12:12 L:D lighting. (A) was kept in the equivalent of very dark night (10–4 lux) in the dark phase, while (B) was exposed to artificially bright illumination in the dark phase and is not yet metamorphosing.
Amphibians are highly sensitive to light and can perceive increases in illumination that are impossible for humans to detect (Hailman and Jaeger). A rapid increase in illumination causes a temporary reduction in visual acuity, from which the recovery time may be minutes to hours. In this manner, a simple flash of headlights can arrest activity of a frog for hours. Frogs in an experimental enclosure ceased mating activity during night football games when lights from a nearby stadium increased sky glow.
Artificial light interferes with the production of the hormone melatonin, which is involved in regulating many important functions, including sexual development, thermoregulation, adaptation of eyes to the dark, and skin coloration. Current research shows that artificial lighting slows larval amphibian development in the laboratory. (Fig.2)
According to a report published by the American Medical Association, artificial lighting should try to reduce the amount of amphibian ecosystem disruption by adjusting the artificial lighting at night, especially streetlights, below 3000K.
Ref.:
2. Moore, M. V., S. J. Kohler, and M. S. Cheers. Artificial light at night in freshwater habitats and its potential ecological effects. Ecological consequences of artificial night lighting. Island Press, Washington, D.C.
3. Hailman, J. P., and J. G. Jaeger. A model of phototaxis and its evaluation with anuran populations. Behaviour.
Jae Ho Lee, Ph.D 
Biologist

* Next week’s topic: Light and Human Body Summary I

You can find "Interesting Story about Light Science” series on the link below. 
Seoul Semiconductor / ohc@seoulsemicon.com 
97-11, Sandan-ro 163beon-gil, Danwon-gu, Ansan-si, Gyeonggi-do, Republic of Korea 
Unsubscribe