detached sea – Detached tube feet and tentacle tissues from a scarlet sea cucumber (Psolus fabricii) survived for more than three years in flowing seawater without special nutrients or antibiotics, researchers report in Science Advances. The finding challenges simple ideas o
In a tank of fresh seawater, something small and tube-like should have disappeared quickly. Instead, it lingered.
During a routine transfer of a scarlet sea cucumber between lab tanks. marine ecologist Annie Mercier’s colleague noticed that the animal had left behind a few podia—small tubelike appendages it uses for movement—on the bottom of the tank. “We would have expected those to decay and waste away quite rapidly. but several days later they were still there. ” Mercier said. of Memorial University of Newfoundland in St. John’s, Canada.
It wasn’t the first time similar detachments had happened in nature, Mercier noted. But it was the first time the lab team watched the aftermath last.
That odd durability pushed Mercier and colleagues to test other pieces of the same animal. Using a scalpel, they cut off additional tissues, including tentacles and body wall. The results were stark: the body wall tissues died within weeks. while the tube feet and tentacles survived for more than three years.
The species at the center of the work is the scarlet sea cucumber, Psolus fabricii. The researchers reported that detached tissues from appendages of this species survived for more than three years in flowing seawater without special nutrients or antibiotics. The study appeared May 29 in Science Advances.
Under a typical compound microscope, the team tracked what the tissue was doing instead of simply lying in wait. They observed cleaning of the wound where the tissue was cut—clearing out old dead cells—and they saw division of living cells. When researchers added amino acids labeled with a trackable atomic tag to seawater. they could see that the tissue absorbed the nutrients. And even after burial in a couple of centimeters of mud, the tissue did not decay.
Mercier described how the mystery turned into an experiment with a name. “We started calling it our ‘zombie project,’” she said. “It’s a piece of tissue that isn’t decaying. It’s still acquiring nutrients. reshaping itself. evolving and doing all sorts of living things. yet it’s not necessarily a living organism in the traditional sense.”.
Not everyone is surprised by the talent sea cucumbers can show. José García Arrarás. a regenerative biologist at the University of Puerto Rico in San Juan. said the finding is “an amazing finding. ” but not entirely surprising. Some sea cucumber species can be cut in half, with each half regenerating completely. “But [the work] raises fascinating questions,” García Arrarás said. “What kind of cells are they?. How do they feed?. Can these tissues outlive the animal itself?”.
Beyond the name—zombie tissue, undead by any casual definition—scientists are now faced with a harder problem: how to describe life when it’s severed.
García Arrarás said the work could help researchers study changes that occur during aging. because the detached tissues represent a striking range of “ages” drawn from the same starting material. “They have tissues that are a week old and others three years old. coming from the same original tissue. ” he said.
Still, he argued that the next crucial step is to look inside the cells themselves. “However, a key next step should be detailing characteristics of the cells within the tissues. ‘You need to know exactly what you have’ before you can understand what’s going on,” he said.
For now. the central scene remains unsettlingly simple: a cut-off piece of sea cucumber tissue. left in seawater. not only persists—it clears wounds. divides. takes up nutrients. reshapes itself. and resists decay for years. If scientists can’t yet say what kind of living system it represents. they can at least agree on the scale of the surprise.
sea cucumber Psolus fabricii regenerative biology detached tissue zombie project Science Advances marine invertebrates wound cleaning nutrient uptake aging research