Moon jellyfish, Aurelia aurita, also known as common jellyfish or saucer jellyfish, can be found in the Atlantic, Pacific, and Indian Oceans. They are typically found near the coast in warm, tropical waters and can be recognized by their colorless saucer shaped bell, with four thick ‘arms’ and lots of small tentacles. But they don’t start out looking like recognizable jellyfish.
They begin as free-swimming larvae (planula) and after floating around for some time, they settle onto a hard surface and become sessile, asexual polyps. The polyps then divide themselves into stacks of saucer-shaped clones (strobila) that eventually break off and float away. These clones, known as ephyra, are tiny, immature jellyfish that take about three months to mature into adult moon jellies.
Scientists have long known that the transformation from polyp to jellyfish is triggered by environmental signals, but the exact process remained unknown. Now, researchers have discovered that a novel metamorphosis hormone is responsible for the transition. The hormone accumulates during the cold winter and induces a “synchronized emergence of jellyfish” in the spring.
“Now we know in detail why and how Aurelia polyps turn into jellyfishes,” Konstantin Khalturin of the Okinawa Institute of Science and Technology said in a news release. “We are also able to control polyp-to-jellyfish transition with an extremely powerful chemical inducer.”
In natural conditions, the polyp-to-jellyfish transition takes weeks, but in the lab, researchers can force the transition in just 48 hours.
The researchers suggest that this new understanding may help control moon jellyfish blooms, which can cause a range of problems from disrupting fisheries to shutting down nuclear reactors.
Researchers could induce metamorphosis at the wrong time, like in the beginning of winter instead of spring. That way, Khalturin explained, “young jellyfish with nothing to eat will die, and there would be no jellyfish bloom the following summer.”
You can read the full study here: Regulation of Polyp-to-Jellyfish Transition in Aurelia aurita.
Copyright © 2014 by Marine Science Today, a publication of Marine Science Today LLC.