The rhythms of life for marine animals, from the smallest to the largest, are regulated by the rising and setting of the sun. Microscopic plankton form the foundation for the marine food chain, rising from the depths to feed as dark falls, descending again when it turns light. Introduce a bright light from a passing ship, and the plankton scatter, stop feeding, and head lower to escape the light, no longer available as a food source for many marine creatures that dwell at higher levels.
Migratory seabirds become disoriented, resulting in collisions and lost time and energy, when they encounter light at night, whether it’s from coastal communities, a passing ship, an oil and gas platform, or a wind farm. A study of seabirds that nest in Aotearoa New Zealand was able to identify the number of offshore light events on a group of birds’ migratory path as well as changes in their behaviour, with some birds more affected than others.
Despite efforts to reduce the amount of light emitted, over 1,800 birds were grounded on the deck of a lobster boat over the course of 8 years. The majority of the groundings occurred on just 7 dark, misty nights when there were no other light sources.
The presence of ships in front of cliffs with colonies of nesting birds was found to reduce the number of times the birds entered the colony by 18%.
Coral reefs, found in very clear waters, are adversely affected by light pollution as it interferes with their feeding and reproductive cycles.
Sea turtles require dark beaches to lay their eggs, but lighting from streets, resorts, and restaurants result in beaches that are almost as bright at night as they are during the day. Baby turtles, that would normally head towards moonlight on the ocean when they’re born, can be confused by city lights and head inland instead.
Citizens can play a role in addressing threats to the environment. Increased light pollution from urban and touristic development on the island of Puerto Rico posed a grave threat to sea turtles. Legislation was introduced to regulate light near turtle nesting sites, but it wasn’t enforced. Environmental organizations established a lighting retrofit program to monitor light levels and assist property owners in retrofitting their lights, gaining useful insight for organizations seeking to undertake similar programs.
22% of the world’s coastlines are affected by light pollution every night to a depth of at least 10 metres in economic zones. It’s not only coastal areas that are affected. Some of the most serious light pollution is far out to sea around offshore oil and gas platforms, wind farms, and islands.
The solutions to artificial light pollution aren’t that difficult. Turn off unnecessary lighting (e.g. empty office buildings); choose lights in the red-amber spectrum (such as amber lighting along coastal highways); dim the lights and point them downwards to prevent sky glow. However, present efforts to control light pollution are limited and focus on individual light sources, ignoring the overall accumulated impact. In addition, current standards and regulations focus on human light requirements and fail to take into consideration the environmental impact. Enforceable regional limits on emissions and green certification for eco-friendly lighting that take into account the maximum allowable deterioration of the night environment are badly needed.
References
From the Beach to the Seafloor, Light Pollution Interferes with Marine Life [DarkSky]
Q&A: Ocean Light Pollution Has Been Invisible for Too Long [Dialogue Earth]
The Global Ocean Artificial Light At Night Network [GOALANN]
Estimating Exposure of Vulnerable Seabird Populations to Offshore Light Pollution [New Zealand Department of Conservation]
Light from Ships Disorients, and Even Kills, Seabirds [Hakai Magazine]
The Effects of Temporally Distinct Light Pollution from Ships on Nocturnal Colony Attendance in a Threatened Seabird [Journal of Ornithology]
New Atlas Illuminates Impact of Artificial Light in the Ocean at Night [Mongabay]
Light Pollution is Fixable. Can Researchers and Policymakers Work Together to Dim the Lights? [NCBI]
Keeping Light Pollution at Bay: A Red-Lines, Target Values, Top-Down Approach [Science Direct]
Tackling Light Pollution: Lessons from Puerto Rico [The State of the World’s Sea Turtles]
Further Information
Is It a Star or a Satellite? [EcoFriendly West]
Looking for the Stars in Western Canada [EcoFriendly West]
Photo credit: https://www.flickr.com/photos/apmckinlay/53991296308/
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