Light at night is harmful for amphibians, new research shows – via Herp Digest

Exposure to light at night has potential to make amphibians more susceptible to additional stressors

May, 28, 2019 Press Release - Binghamton University, State University of New York  

Newswise — BINGHAMTON, N.Y. – Light at night might be convenient for humans, but it’s having a detrimental effect on amphibian populations, according to new research from Binghamton University, State University of New York. 

“Research on the effects of light pollution has recently seen a surge in popularity,” said Binghamton University Assistant Professor of Biological Sciences Jessica Hua. “It's difficult to find any place on Earth that is not affected by even minimal light pollution. We recognized a gap in the research and realized that not much was known about how light pollution can impact amphibians. Since amphibians are sensitive to environmental changes, they make great models for studying how pollution of any type can impact other species.”

Hua, along with graduate student Grascen Shidemantle and undergraduate student Dyllan May, exposed wood frogs to a control and two anthropogenic light conditions: intensified daytime illuminance and artificial light at night (ALAN). They found that both the intensified daytime illuminance treatments and the ALAN treatment decreased hatching success in tadpoles. Tadpoles that were reared in the ALAN treatment, on the other hand, were larger, less active, more sensitive to road salt pollution and had more parasites.

“Overall, I think the main thing we learned from this study is that exposure to light at night has the potential to make amphibians more susceptible to the effects of additional stressors, like road salt and parasites,” said Shidemantle. “This is concerning since these are common stressors that many amphibians have to cope with. The light at night on itself might not have too much of a negative effect on its own, however, since wildlife rarely encounter just one stressor in their natural habitat, the combination of light pollution with additional stressors may have negative impacts on amphibian populations.”

Shidemantle is considering looking at how light pollution impacts other organisms in wetland ecosystems that amphibians might interact with, such as damselfly larvae which are common predators of tadpoles. She received a grant from the National Science Foundation this year to further explore the effects of light pollution on amphibians.

“It is critical to understand how humans impact wildlife so that we can make more responsible decisions about how we proceed with activities such as urbanization and construction,” said Shidemantle. “Also, it is likely that these effects of light pollution extend beyond just amphibians—the impacts on amphibians may have indirect effects on other organisms that amphibians interact with in their ecosystem.” 

The paper, "The effect of intensified illuminance and artificial light at night on fitness and susceptibility to abiotic and biotic stressors,” was published in Environmental Pollution.

Three quarters of deep-sea animals make their own light

Date: April 10, 2017

Source: Monterey Bay Aquarium Research Institute

Ever since explorer William Beebe descended into the depths in a metal sphere in the 1930s, marine biologists have been astounded by the number and diversity of glowing animals in the ocean. Yet few studies have actually documented the numbers of glowing animals at different depths. In a new study in Scientific Reports, MBARI researchers Séverine Martini and Steve Haddock show that three quarters of the animals in Monterey Bay waters between the surface and 4,000 meters deep can produce their own light.

You would think it would be easy to count the number of glowing (bioluminescent) animals in the ocean, just by looking at videos or photographs taken at different depths. Unfortunately, very few cameras are sensitive enough to show the pale glow of many marine animals. Below 300 meters (1,000 feet) the ocean is essentially pitch black, so animals don't need to glow very brightly. Also most animals don't glow continuously because making light takes extra energy and can attract predators.

Because of the difficulty in counting glowing animals at depth, most previous estimates of the proportion of glowing animals were based on qualitative observations made by researchers peering out the windows of submersibles. Martini and Haddock's study is the first ever quantitative analysis of the numbers and types of individual glowing animals at different depths.

Continued 

Why are moths fatally attracted to light?

Saturday 28 February 2015

Moths are not attracted to light. They navigate by light, operating under the assumption that the main source of light is far, far away – ie, the moon. If, say, a moth keeps the moon always on its left-hand side, it will fly in a vaguely straight line for a fair while. (It's obviously more complicated than that, but the principle is the same.)

But if the light is a porch light, keeping that on its left-hand side will make the moth fly in circles (and we won't see it), in outward spirals (and we won't see it), or in inward spirals (and we will see it as flying 'towards the light').

This has worked out pretty well for them for 190,000,000 years, but in the past 50-75 years, man-made lights have made things occasionally confusing. Before that, the only thing that would confuse them would be rare small fires. (If a moth is in the middle of a forest fire, navigation is the least of its problems.) And again, even there, many of the confused moths would not be harmed, but would merely orbit in circles or outward spirals until the fire died out.

Read on ...