RAMAT GAN, Israel, Dec. 15 (UPI) -- Corals spawn just once a year. Studies show they use moonlight to track the ideal time and conditions for releasing eggs and sperm.
But new research, published in the journal eLife, suggests an increase in light pollution may be threatening the abilities of coral colonies to reproduce.
When researchers in Israel collected 20 colonies from a reef and exposed them to varying light conditions in the lab, only those exposed to normal day and night light levels successfully spawned. The colonies kept in the dark at night or exposed to artificial light at night failed to reproduce.
Researchers at Bar-Ilan University found both the artificial blackout and presence of artificial light disrupted the coral genes that dictate spawning.
As part of the new study, scientists in Israel collaborated with researchers in Australia, who have been studying the role of light in coral reproduction. Unlike Red Sea reefs off the coast of Israel and Jordan, the coral reefs being studied among the Great Barrier Reef are protected from artificial light.
Researchers there found coral rely on photosensitive molecules, such as cryptochromes or opsins, to monitor factors like the calmness of the water, salinity, food availability and twilight levels. These molecules sync with the power of varying light levels.
"If the process is disrupted, we assume reefs might work round it for a few years using the mechanisms they have to cope with a variable world, but we just don't know what the impact could be on their long-term health," study author Paulina Kaniewska, a researcher at the University of Queensland, said in a press release.
The results in Israel, however, suggest the influence of light pollution may have more dramatic and quickly evident effects than previously thought.
"Sexual reproduction is one of the most important processes for the persistence of coral reefs," said lead researcher Oren Levy of Bar-Ilan University.
Levy would like to see more reefs protected from the light pollution of developing coastlines.