Upside-down Jellyfish Create ‘Stinging Water’ That Kills Prey by Launching Mucus ‘Grenades’

Scientists say they’ve unraveled the thriller of the weird “stinging water” phenomenon lengthy reported by swimmers and snorkelers who’ve strayed near upside-down jellyfish—the creatures launch poisonous mucus crammed with tiny “grenades” of stinging cells.

Individuals who’ve skilled stinging water say it appears like being stung by a jellyfish, regardless of not having had any contact with the animals. Several hypotheses have been proposed to elucidate the phenomenon—together with severed jellyfish tentacles, sea lice, anemones or different stinging marine animals—nonetheless, the precise trigger has remained elusive.

But now, a research revealed within the journal Communications Biology, reveals what could also be the true offender.

“[This study] began when I and other marine biologists were concerned about the source of ‘stinging water’—an irritating sensation that occurred while in the mangrove forest waters studying upside-down jellyfish, and working together with aquarists at major public aquariums,” Cheryl Ames, an creator of the research from Tohoku University, Japan, and the Smithsonian’s National Museum of Natural History, informed Newsweek.

“There were several theories exchanged by fellow marine biologists, and comments posted online by people after experiencing stinging water during snorkeling or swimming in those areas. We wanted to find out the scientific explanation behind the long-standing stinging water puzzle,” she stated.

Ames and colleagues investigated a jellyfish from the genus, or group of species, Cassiopea—that are generally known as “upside-down jellyfish.” These animals are present in heat coastal waters, reminiscent of mangroves, bays and lagoons, in Australia, Bermuda, Fiji, the Florida Keys, the Caribbean Islands, the Hawaiian Islands, Indonesia, Palau, Panama, Papua, New Guinea, and the Red Sea, in addition to invasively within the Mediterranean Sea close to Turkey.

“Cassiopea, like its common name upside-down jellyfish suggests, is found facing upward on the bottom of shallow coastal waters in bays, mangroves and lagoons—pulsing rhythmically in groups of hundreds to thousands of individuals,” Ames stated.

“Like all jellyfish, Cassiopea is a carnivore, but different from many jellyfish, it also has single-cell algae living in its cells. This symbiotic relationship allows Cassiopea to get nutrients through the alga’s photosynthetic activity—much like a plant makes its own food,” she stated.

When these jellyfish feed they launch clouds of mucus which they use to catch prey like a internet. They then suck within the mucus crammed with prey—reminiscent of shrimp and different plankton—utilizing their frilly feeding buildings to devour the meal.

This picture exhibits three upside-down jellyfish in a lab on the Smithsonian’s National Museum of Natural History.
Allen Collins/Cheryl Ames

The researchers determined to research this mucus within the lab, suspecting that it may very well be liable for the stinging water sensation. Using superior microscopic methods they had been capable of establish tiny lots of stinging cells known as “cassiosomes,” which the jellyfish use nearly like “mobile grenades” to entice and kill prey. These buildings are capable of transfer independently on account of tiny hair-like filaments often known as cilia.

“Stinging water is caused by people coming in contact with the mucus of upside-down jellyfish, without actually touching the jellyfish,” Ames stated. “We found that the mucus contains tiny moving clusters of cells—that are sent out remotely from the jellyfish into its mucus, and which sting prey.

“We known as these self-propelled cell lots cassiosomes. Using high-tech microscopy strategies, our group found that the cassiosome outer layer is lined with hundreds of jellyfish stinging capsules known as nematocysts. Nematocysts are toxin-filled capsules usually discovered within the tentacles. The middle is jelly-filled, and likewise incorporates symbiotic single celled algae that matches the sort discovered dwelling within the jellyfish,” she said.

The scientists say that this stinging strategy has never been identified before. However, the team also found cassiosomes in several other related jellyfish species that cause stinging water symptoms.

According to the researchers, most of the jellyfish’s nutrients come from the symbiotic algae living inside it. However, the cassiosome-packed toxic mucus may help the animal to acquire additional food from prey when needed.

“Venoms in jellyfish are poorly understood typically, and this analysis takes our data one step nearer to exploring how jellyfish use their venom in fascinating and novel methods,” Anna Klompen, another author of the study said in a statement.

While the venom of upside-down jellyfish is not particularly powerful, there are potential health impacts for humans.

“The sting just isn’t identified to be actually harmful. No deaths or critical damage have been reported from direct contact with the jellyfish,” Ames said. “However, when scientists studied the pure venom, extracted from the stinging capsules—nematocysts—they discovered that the toxins can destroy cells.

“Additionally, Cassiopea generated stinging water, which we now know is caused by the cassiosomes in the jellyfish mucus, causes a sensation that is itchy-to-burning and—depending on the person—can cause enough discomfort to make them to want to get out of the water.”

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