Light pollution disrupts marine organisms’ hormonal cycles, reproduction: Study

Light pollution disrupts marine organisms’ hormonal cycles, reproduction: Study

Subject :Environment

Section: Pollution

Context:

• A recent study by Cornell University, United States, argued that we should broaden our outlook to consider light pollution’s influence on coastal marine ecosystems, affecting everything from whales to fish, corals and plankton.

Details:

• Marine organisms that evolved over millions of years to adapt to natural light now face an ever-increasing flood of light from anthropogenic sources along the coasts.
• Artificial light can easily wash out the glow of moonlight and starlight, which are important cues for marine organisms.
• This disrupts their hormonal cycles, inter-species behaviour and reproduction.

Impact of artificial light on turtles:

• Compared to prior technologies, LEDs often emit more short-wavelength light and can pierce deep into the water.
• Artificial light at night is harmful to sea turtles in two ways.
• Females trying to find a quiet, dark spot to lay their eggs avoid light and may end up not coming ashore at all.
• The hatchlings head toward inland lights instead of moonlight on the water and then die of dehydration or starvation.

Light Pollution:

• Light pollution can be defined as the introduction by humans, directly or indirectly, of artificial light into the environment.
• Avoidable light pollution refers to light flow emitted at night by artificial light sources which are inappropriate in intensity, direction and/or spectral range, unnecessary to carry out the function they are intended for, or when artificial lighting is used in particular sites, such as observatories, natural areas or sensitive landscapes.

Types of Light pollution:

• Light trespass: When unwanted light enters one’s property, for instance, by shining over a neighbor’s fence.
• Over-illumination: It is the excessive use of light.
• Glare: Glare is often the result of excessive contrast between bright and dark areas in the field of view.
• Blind glare: describes effects such as that caused by staring into the Sun. It is completely blinding and leaves temporary or permanent vision deficiencies.
• Disability glare: describes effects such as being blinded by an oncoming cars lights, or light scattering in fog or in the eye reduces contrast, as well as reflections from print and other dark areas that render them bright, with significant reduction in sight capabilities.
• Discomfort glare: does not typically cause a dangerous situation in itself, and is annoying and irritating at best. It can potentially cause fatigue if experienced over extended periods.
• Clutter: Clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where brightly lit advertising surrounds the roadways.
• Skyglow: refers to the “glow” effect that can be seen over populated areas. It is the combination of all light reflected from what it has illuminated escaping up into the sky and from all of the badly directed light in that area that also escapes into the sky, being scattered (redirected) by the atmosphere back toward the ground.

Impact of light pollution:

• Wastes Energy and Money: Lighting that emits too much light or shines when and where it’s not needed is wasteful. Wasting energy has huge economic and environmental consequences.
• Disrupting the ecosystem and wildlife: Plants and animals depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators.
  • Scientific evidence suggests that artificial light at night has negative and deadly effects on many creatures including amphibians, birds, mammals, insects and plants.
  • Ex: A study has now shown how nocturnal dung beetles are forced to search for cues in their immediate surroundings when they can no longer navigate using natural light from the night sky.
  • The effect of light in the form of fire or lamps attracting migratory and non-migratory birds at night, especially when foggy or cloudy, has been known since the 19th century and was and still is used as a form of hunting. The reasons for disorientation of birds through artificial night lighting are not well known. Experts suggest that the navigation of birds using the horizon as orientation for the direction is disrupted by lighting and sky glow.
• Harming human health: Like most life on Earth, humans adhere to a Circadian Rhythm — our biological clock — a sleep-wake pattern governed by the day-night cycle. Artificial light at night can disrupt that cycle.

Reduction of Light Pollution

• Reducing light pollution implies many things, such as reducing sky glow, reducing glare, reducing light trespass, and reducing clutter.
• The method for best reducing light pollution, therefore, depends on exactly what the problem is in any given instance. Possible solutions include:
• Utilizing light sources of minimum intensity necessary to accomplish the light’s purpose.
• Turning lights off using a timer or occupancy sensor or manually when not needed.
• Improving lighting fixtures, so that they direct their light more accurately towards where it is needed, and with less side effects.
• Adjusting the type of lights used, so that the light waves emitted are those that are less likely to cause severe light pollution problems.
• Evaluating existing lighting plans, and re-designing some or all of the plans depending on whether existing light is actually needed.