Sea Turtles and Light Pollution
Sea turtles have a unique way of nesting, one that involves several factors that are affected by human influence. After a female sea turtle has mated, it will find a beach to lay her eggs. She lays between fifty and two hundred eggs, also called a clutch, in an “egg chamber” she created with her flippers. After one to two months, the eggs will be ready to hatch. [1]
When a baby sea turtle has crawled out of its egg chamber, it must navigate to the water by itself. Normally, the sea turtles emerge at night, due to several reasons. There are often less predators out at night, and if there is a predator, it is harder for the baby sea turtles to be seen in the darkness. The more important reason for the turtle's nighttime journey to the sea is the moonlight and starlight. Using a combination of visual and equilibrioception, the ability to tell spatial orientation, baby sea turtles are able to navigate to the sea. [2] [3]
During the night, the moon and stars reflect off of the ocean, creating a very bright horizon. This contrast of brightness draws the baby sea turtles into the ocean, along with the slope of the beach. This process is called positive phototaxis, where an organism moves towards light. [2]
The Effects of Artificial Light
Artificial light enters the equation when it is brighter than the moon and stars, because it can cause the sea turtles' phototaxis to lead them away from the water. This is dangerous, because the turtles that don’t make it to the water are more likely to get killed by predators. They are also more likely to get killed by humans if they veer too far off course, because of roads, pollution, or someone who isn’t looking where they are stepping. [2] [4]
Why Sea Turtles Matter
Sea turtles are a keystone species, which means that the balance of an ecosystem depends on them. Variation in their population can severely affect other organisms. This makes them important to the overall health of the marine ecosystem. They also help terrestrial ecosystems because the shells of sea turtle eggs contain nutrients that are beneficial to other organisms. [5]
The loss of sea turtle numbers due to artificial impact has a direct impact on the wellbeing of many different ecosystems, and can even have effects on humans. Fisheries and other marine based food sources are directly affected by sea turtle populations, as sea turtles stabilize the populations of many fish species. [5] [6]
Conservation Efforts
Currently, there are several organizations fighting to help preserve sea turtle populations. The Oceanic Society and Sea Turtle Conservancy are currently bringing awareness to this issue. [6] [7]
References
- The State of the World's Sea Turtles — Sea Turtle Lifecycle
- Sea Turtle Conservancy — Artificial Lighting
- Sea Turtle Space Coast — Do Sea Turtles Use Maps?
- ScienceDirect — Research Article on Sea Turtles
- National Park Service — Sea Turtles Matter
- Wiley — Marine Ecology Research Article
- Oceanic Society — Sea Turtle Conservation
