You may have heard that exposure to blue light can disrupt your sleep. As a result, it is also harmful to wildlife.
At an inner-city university, hordes of wallabies are helping researchers understand how artificial light affects the nocturnal marsupials.
La Trobe University graduate researcher Alicia Dimovski is studying how exposure to light affects tammar wallabies.
In one enclosure, they were exposed to light-emitting diodes (also known as LEDs). A second enclosure had shielded blue LEDs similar to the “night mode” setting on your phone or laptop. Wallabies in a third enclosure experienced natural darkness.
After 10 weeks, Alicia took blood samples to test the wallabies’ melatonin levels. As a result, LEDs have a dark side.
The “hormone of darkness”
Like us, wallabies rely on the hormone melatonin to get a good night’s rest. And the level of melatonin produced in our body is regulated by a light-sensitive protein in our eyes called melanopsin. When certain wavelengths of light hit melanopsin, it suppresses our melatonin production. Reduced levels of melatonin in our blood could interfere with our body’s natural sleep-wake cycle.
“Melatonin is known as the ‘hormone of darkness,'” says Alice.
“This is because melatonin production is suppressed by light and maximum production occurs during the dark phase.”
Melatonin is also important for the immune system. In mammals, melatonin acts as an antioxidant, scavenging free radicals.
Free radicals are unstable atoms created by the body as a byproduct of various normal cellular processes. Despite their potential to damage DNA and other cells, the body is perfectly fine with low levels of free radicals. However, when we have an infection, the body’s immune response can cause an increase in free radicals. Without melatonin, this increase in free radicals can lead to oxidative stress, which increases inflammation.
lighten up
Not all light activates melanopsin equally. Blue light with a wavelength between 420 and 440 nanometers is best for activating melanopsin.
In 2009, the Australian government began phasing out incandescent bulbs for energy-efficient alternatives such as LEDs.
Since then, LEDs have become the main source of light for homes, businesses and streetlights in Australia. Unfortunately, energy-efficient light bulbs are causing health problems for nocturnal wildlife.
After 10 weeks of nocturnal LED exposure, Alicia’s wallabies had lower melatonin levels.
“White LEDs cause problems because they contain a lot of blue light, so they’re really effective at suppressing melatonin,” says Alicia.
However, the study found that removing blue light from LEDs made a big difference in melatonin levels. In fact, wallabies exposed to amber LED light had melatonin levels equal to wallabies experiencing natural darkness.
No sleep in the suburbs
Beyond melatonin, for wallabies, the changing light level throughout the four seasons is a timer for vital processes such as reproduction.
“Animals that breed at a certain time of year, such as tammar wallabies, rely on this biological clock to ensure that births occur when there is enough food to raise their young,” says Alice.
“Many Australian mammals have been shown to reduce their activity even under a full moon due to increased risk of predation. So even very low levels of light pollution can disrupt our wildlife.”
The WA Department of Biodiversity, Conservation and Attractions has guidelines for businesses to reduce light pollution. However, they are not legislated or enforced. Compliance with the guidelines is entirely voluntary.
“The DBCA promotes the guidelines through education with industry and government agencies to ensure best practice lighting design and reduce the potential impact of artificial light on wildlife,” says a spokesperson of the DBCA.
So, if you’re the best friend you can be to the nocturnal wildlife near your home, consider getting blue wavelength filters for your LEDs and placing them closer to the ground. They’ll love ‘roo for it!
This article was originally published on Particle. Read the original article.