This was established by Israeli scientists in the course of laboratory experiments
Corals with photosynthetic zooxanthellae, which form shallow water reefs, capture sunlight penetrating the water surface.
Other types of corals are able to grow at depths of up to 6,000 in dark and cold water environments. And they use bioluminescence as bait for prey. “The fluorescent coloration accentuates the mouth or the tips of the tentacles. This ability can be considered an important adaptation for seafloor corals, especially those colonies where photosynthesis needs to be supplemented with other sources of energy,” said Yossi Loya, a marine ecologist and senior author of the study from Tel Aviv University.
In the laboratory, the scientists determined whether the small Artemia salina shrimp would swim towards a green or orange target, fluorescent or transparent, reflective or opaque, located at the other end of the aquarium. It turned out that the shrimp are indeed attracted to the fluorescent signal.
Similar results were obtained as a result of experiments conducted in the Eilat Gulf of the Red Sea.
Or Ben-Zvi, a coral reef researcher at Tel Aviv University, comments: “Despite the gaps in current knowledge regarding the visual perception of fluorescence signals by plankton, we have provided experimental evidence for the role of fluorescence in corals in attracting prey.”