When a sea turtle hatches, it heads toward the light. Under natural conditions, that means the ocean. But if the beach is near a bright city, it might head inland, where it can be nabbed by a predator, hit by a car, or die of exhaustion.

Baby turtles aren’t the only sea creatures affected by artificial light. Among its many impacts, the light can throw off the reproductive cycles of corals and others, make it harder for fish to hide from predators, and endanger beds of kelp by providing extra light for the urchins that feed on them.

Much of the life in the oceans depends on the light of the Moon and stars – even at depths of hundreds of feet. But the glow of coastal cities, oil rigs, and passing ships can throw things out of whack.

Corals, for example, time their spawning by the phases of the Moon. But artificial lights disrupt the timing, endangering coral reefs. Microscopic organisms move up and down in the water as the light changes to find food or avoid predators. But that cycle is disrupted by artificial lights as well.

Depending on how clear the water is, the light can penetrate anywhere from a few feet to more than a hundred feet. And bluer light, which is produced by modern LEDs, goes deeper than redder light.

Some coastal cities limit outdoor lightning, or build barricades to shield the beaches and the water close to shore – making life a little safer for baby sea turtles and other marine creatures.

Script by Damond Benningfield