As we mentioned in the previous post, marine species are exceptionally sensitive to light. Today, we would like to share examples of how sea turtles’ behaviour has been affected by the increase in artificial lights.
According to the International Dark-Sky Association (IDA) (2015), sea turtles are the most highly affected species on planet Earth. In recent years, sea turtles population faced a massive decline and light pollution is one of the main culprits (Witherington et al., 2014). The artificial lights have largely affected the sea turtles behaviour on nestling and hatching (Thums et al., 2016). The artificial light at the beach area has misguided the sea turtles spawning and hatching behaviour.
Naturally, female sea turtles prefer a darker environment to lay eggs. According to Witherington & Martin (2003), a sea turtle’s choice of nesting location is linked to the amount of brightness present on the beach. The increased usage of artificial lights for human activity has confused or misguided the female turtles to lay eggs in an inappropriate place (IDA, 2015). Hence, with the global increase in artificial light usage, potential nesting areas for the sea turtles are on the decline.
The study also showed that the hatchling process suffered huge adverse impact from artificial lights. According to the study by Witherington & Martin (2003), baby sea turtles are most likely to hatch in the night to avoid overheat and predator.
After hatching, the baby sea turtles were to be guided by moonlight or brighter horizon on the sea surface to return to the sea (IDA, 2015). Natural light source plays a major role in helping new-born sea turtles search for their ways to the ocean. However, the brightness of artificial light has attracted the new-born sea turtles leading them to the wrong direction such as roads, cities, civilization area, and some might end up being killed.
As a crucial nestling spot for several types of sea turtle, the authorities in Florida, USA have taken several initiatives to protect the sea turtles. These initiatives include decreasing the usage of artificial lights, long-waved light source (e.g. long-waved length LEDs), and exposure of beach to bright lights at night (Witherington & Martin, 2003).
This issue has shown that the lights on land not only affects humans and animals on land but it also adversely impacts marine lives. Hence, the impact of light pollution might be greater than we expected.
Source: https://www.youtube.com/watch?v=3fKhpDmYO5I
Cheers,
Shee Wen & Nicole 
References:
International Dark-sky Association. (2015). Sea Turtle Conservation. Retrieved October 30, 2020, from https://www.darksky.org/our-work/sea-turtle-conservation/
Thums, M., Whiting, S.D., Reisser, J., Pendoley, K.L., Pattiaratchi, C.B., Proietti, M., Hetzel, Y., Fisher, R. & Meekan, M.G. (2016), “Artificial light on water attracts turtle hatchlings during their near-shore transit”, Royal Society open science, vol. 3, no. 5, pp. 160142-160142.
Witherington, B., & Martin, E. (2003). Understanding, Assessing, and Resolving Light-Pollution Problems on Sea Turtle Nesting Beaches. Fl. Mar. Res. Inst. Tech. Rep. TR-2.