Artificial Light Pollution Disrupts Coral Sleep in Eilat Reef, Study Finds

The coral reef in the Gulf of Eilat, one of the world's most beautiful and unique coral ecosystems, faces a significant but often overlooked threat from artificial light pollution. This national natural treasure, attracting researchers and tourists globally, is vulnerable to light emitted from nearby roads, beachfront cafes, and boats. Unlike other ecological problems requiring complex solutions, this issue may be addressed with relatively simple measures such as reducing or redirecting artificial lighting.

Coral reefs depend on tiny symbiotic algae living within their tissues that provide energy through photosynthesis. These corals, like humans, require rest, and disruptions to their nighttime environment can impair their physiological functions. Until now, research focused mainly on reproductive cycle disturbances caused by light pollution, but new studies have revealed how even low-intensity, brief artificial lighting affects coral photosynthesis and health.

A multidisciplinary research team from the Hebrew University and the University of Illinois used a unique long-term monitoring system in Eilat to study 16 coral colonies at depths of 7 and 42 meters. They measured the natural light emission from the symbiotic algae, which indicates unused energy in photosynthesis, and applied advanced "noise analysis" to detect subtle fluctuations in this emission. Surprisingly, these fluctuations were stronger at night, suggesting corals react intensely to brief light flashes after dark, triggering prolonged stress responses.

This heightened nighttime sensitivity means even dim or short-lived artificial lights, previously considered harmless, can disturb coral rest and energy systems. The researchers emphasize that coral responses to artificial light differ significantly from natural daylight responses. The study highlights the need for lighting standards on beaches and coastal infrastructure in the Gulf of Eilat to protect the reef's health.

While further research is needed to fully understand the damage extent, the solution appears straightforward: lowering light intensity or changing its angle can help restore natural darkness and allow corals to rest. These findings will be presented at the 54th Annual Science and Environment Conference in Jerusalem on July 8-9, aiming to promote smart lighting policies that safeguard this vital ecological asset.