Most Corals Don't Move; Researchers Find 'Moving' Corals Attracted Toward a Particular Light
Recent research shows that corals are attracted to a particular light while moving. This preference was noted by experts in specimens collected from the coast of Cairns, Australia, stated CNN. These corals were taken to the Queensland University of Technology for testing and underwent both single and dual light trials for the study. They all belonged to the Cycloseris cyclolites species. Findings regarding these examinations have been published in PLOS.One.
Most corals do not move, their way of living involves being attached to the surface of their habitat (a reef made out of the bones of their ancestors). Some species though have motion capabilities like their evolutionary successor jellyfish. One of them is the tiny mushroom coral named Cycloseris cyclolites. The movement of the specimens was observed using time-lapse videos, which featured these creatures scooting in their tanks.
The pace was very slow, as per experts. Researchers claimed that one of the corals just moved 43.73 millimeters in 24 hours. The first hour had most of the creatures just swelling their outermost tissues. "I watched this thing for a very long time, thinking it was going to pop," cnidariologist Brett Lewis, from the University of Queensland who led the study shared. "I was like, 'Christ almighty, this is taking a long time to happen'." The tissues after inflation, contracted, and then the surface contact transferred to a kind of 'foot' structure. By following this pattern, the creature moved an inch. Experts stated that this movement was similar to the pulsed swimming motion usually displayed by jellyfish.
Researchers also noted that the corals moved towards a particular light source. "Our findings suggest that pulsed inflation is not just a survival strategy but a critical mechanism for migration and navigation," Lewis said, stated Science Alert. "The ability of Cycloseris cyclolites to move towards specific light sources is a fascinating parallel to other marine species like jellyfish, which suggests they are more neurologically sophisticated than previously thought."
For the exercise, the whole tank was shrouded in darkness, with a white or blue light source shining at one end. Researchers recorded that more corals became active due to the blue light. 86.7 percent of corals moved toward the blue light, while only 13.3 percent got attracted to white light. For three corals, experts offered the option of white and blue light. All three creatures chose blue light.
The blue light sources were similar to the illumination available in the deep water sand beds, which serve as the habitat of corals. In those environments, wavelengths associated with white light cannot reach. Instead, the wavelength of white light is associated with shallow waters, which have been determined to be dangerous for corals. Hence, experts feel most corals avoid white light, as it acts as an indicator of fatal situations.
Researchers believe these movements will help them to understand how corals deal with challenges in their habitats. "The findings also have important ecological implications," Lewis said. "Understanding their movement strategies could help scientists predict how migratory corals might resist, survive, or adapt to changes in environmental conditions such as sea surface changes caused by climate change, which can be reduced by the deeper waters these corals migrate to. With these climate-driven factors increasing, the faster the migration, the higher the chance of survival."