Sea turtles (Cheloniidae and Dermochelyidae families) are beloved by many, featured in animated kids movies like Finding Nemo as well in many viral videos showing newly-hatched babies scurrying into the ocean. Many people who live near them know they are endangered and care about them. What they don’t know is that their back porch light to their beach house is causing trouble. Artificial light pollution is a relatively new threat for sea turtles, disrupting many of their physiological functions.
Florida’s beaches are where many sea turtle species call home, nesting under the sand in the dunes. As beach tourism in the state continues to grow, more and more artificial light is spreading along the coastline, threatening these nesting sites. The artificial light disrupts the turtle’s circadian rhythm, confusing them if it is nighttime or daytime, making them more vulnerable to nocturnal predators who catch them unaware (Hu et al., 2018). In addition, when baby turtles are hatching, light pollution can disorient them during their dash to the ocean (Long et al., 2022). Geo-spacial collected data shows, however, that sea turtles are already avoiding areas of high light pollution (figure 1). Therefore, continued expansion of lights along Florida’s beaches could continue to reduce usable habitat for sea turtle nesting activities.
Figure 1. Geo-spacial map of artificial light on the Florida coast vs. density of Loggerhead turtle nests (Hu et al., 2018)
Luckily, the people of Florida have the sea turtles backs. Legislation exists that prohibits certain wavelengths of light to be visible from the beach, requiring shielding of exterior light bulbs (Mascovich et al., 2018). Education programs are also conducted to inform tourists who may be staying at a place close to the beach, informing them to turn off their exterior lights at night to protect nests. These programs are conducted with mixed success, however, with guests often still leaving their lights on throughout the night (Mascovich et al., 2018).
New lighting technology has also recently become an idea of preventing further and reducing current light pollution. For example studies show that Loggerhead sea turtles (Caretta caretta) are generally more sensitive to shorter wavelengths of light at less than 560 nanometers (Long et al., 2022). Thus, the state of Florida has been testing a new 624 nanometer lamp to use along coastal highways, to try and reduce light pollution that highways create. A study conducted by Long et al. showed that these new lamps DO work, with hatching turtles finding their way to the ocean just fine (2022).
Overall, while these solutions do work, they are not strictly enforced. There must be more legislative action and encouragement to use higher frequency light near the nesting locations to reduce light pollution.
Hu, Z., Hu, H., & Huang, Y. (2018). Association between nighttime artificial light pollution and sea turtle nest density along Florida coast: A geospatial study using Viirs Remote Sensing Data. Environmental Pollution, 239, 30–42. https://doi.org/10.1016/j.envpol.2018.04.021
Long, T. M., Eldridge, J., Hancock, J., Hirama, S., Kiltie, R., Koperski, M., & Trindell, R. N. (2022). Balancing human and sea turtle safety: Evaluating long-wavelength streetlights as a coastal roadway management tool. Coastal Management, 50(2), 184–196. https://doi.org/10.1080/08920753.2022.2022974
Mascovich, K. A., Larson, L. R., & Andrews, K. M. (2018). Lights on, or lights off? hotel guests’ response to nonpersonal educational outreach designed to protect nesting sea turtles. Chelonian Conservation and Biology, 17(2), 206. https://doi.org/10.2744/ccb-1299.1