If you think you’ve seen it all — how about a jellyfish that can actually get younger?

There is a jellyfish called turritopsis, which has the remarkable ability to age in reverse.

“When the environment is bad, this animal can essentially go from its adult body form back, back, back to its larval form, and then start all over again,” explains marine biologist Steve Palumbi. “It’s called transdifferentiation. It’s the only critter known to be able to do that.” 

Life in the ocean is a longstanding mystery to most humans. In a new book called “The Extreme Life of the Sea,” marine biologist Steve Palumbi and his novelist son Tony showcase an underwater world filled with fascinating sea life that has managed to survive against all odds.

Steve Palumbi says writing the book was a kind of experiment. “Can you take the narrative style and approach that a novelist would use,” he asks, “and combine it with what a scientist would do and come up with an environmental narrative that is more engaging than we’re used to?”

Palumbi says, “You don’t really care about the plot [of a book] until you care about the characters. So we wanted to write a book that made you care about the characters.”

And their “characters” are amazing.

Take the Stoplight Loosejaw, which lives in the deep sea where there is no light and not much food. Palumbi calls the Loosejaw an “ocean predator with night vision goggles.”

“It has two searchlights that beam out from under its eyes,” Palumbi says. “They’re not the typical blue-green [light] of bioluminescence. These searchlights are red — and they also change their eyes so that they can see red … So they can prowl around with these searchlights on and nobody else can see them, but they can see their prey.”

Perhaps one of the oddest of all the characters Palumbi describes is the Anglerfish — the fish made popular in the movie Finding Nemo. Palumbi says scientists studied them for a century or more, “always bemoaning the fact they could only find females.”

Then a parasitologist who was investigating the parasites the females always have on them discovered that the parasites were the males. The parasitic males were attached to the females, “depending totally on the females for everything,” Palumbi says.

“After they bite the female,” he explains, “their jaws dissolve, and then their brains dissolve, and then their guts dissolve and then their blood systems mesh with the females, and all they are just at the end is a testes that’s there to fertilize the female’s eggs when she’s ready.”

As with many stories, our fascination turns to concern when the characters we like are threatened. And the biggest threat to these characters is humanity.

“The real problem,” Palumbi says, “is that this huge ocean, with all these creatures in it, is not big enough that it is immune to the kinds of changes that we can make in it.”

Overfishing is one serious threat. It disrupts the normal food chains of the ocean. When humans fish heavily, we cause the food energy in the chain to “clump up” at points in the chain where it ordinarily wouldn’t, throwing the ocean life out of balance.

And, of course, there’s climate change — which Palumbi calls a “pervasive, growing and huge problem.” Palumbi says climate change is making the oceans warmer, more acidic and stormier. These problems — already visible now — are projected to grow into the future.

Palumbi compares the process to trying to stop a speeding car. “It’s like you’re booming along … and all of a sudden you see the red brake lights in front of you, and you think, ‘OK, we’ve got to stop.’ But there’s a stopping distance. You can’t stop immediately … That stopping distance for climate change is about 50 years.”

“If we stopped the process by which climate change is happening,” Palumbi continues, “it’s still going to take 50 years or so for the oceans to absorb what we’ve already put into the atmosphere and begin to get better.”

Still, Palumbi hopes readers will share his sense of “guiltless wonder” about the extraordinary life of the ocean. The book, he says, is meant to entertain, to give the readers the sense of “Wow, I never knew that.”

“[T]hese critters out there are not just seafood,” he says. “They live in all the corners of the ocean. They can live and thrive in amazing places with amazing abilities, and … they add to the wonder of our planet.”

There is a jellyfish called turritopsis, which has the remarkable ability to age in reverse.

“When the environment is bad, this animal can essentially go from its adult body form back, back, back to its larval form, and then start all over again,” explains marine biologist Steve Palumbi. “It’s called transdifferentiation. It’s the only critter known to be able to do that.” 

Life in the ocean is a longstanding mystery to most humans. In a new book called “The Extreme Life of the Sea,” marine biologist Steve Palumbi and his novelist son Tony showcase an underwater world filled with fascinating sea life that has managed to survive against all odds.

Steve Palumbi says writing the book was a kind of experiment. “Can you take the narrative style and approach that a novelist would use,” he asks, “and combine it with what a scientist would do and come up with an environmental narrative that is more engaging than we’re used to?”

Palumbi says, “You don’t really care about the plot [of a book] until you care about the characters. So we wanted to write a book that made you care about the characters.”

And their “characters” are amazing.

Take the Stoplight Loosejaw, which lives in the deep sea where there is no light and not much food. Palumbi calls the Loosejaw an “ocean predator with night vision goggles.”

“It has two searchlights that beam out from under its eyes,” Palumbi says. “They’re not the typical blue-green [light] of bioluminescence. These searchlights are red — and they also change their eyes so that they can see red … So they can prowl around with these searchlights on and nobody else can see them, but they can see their prey.”

Perhaps one of the oddest of all the characters Palumbi describes is the Anglerfish — the fish made popular in the movie Finding Nemo. Palumbi says scientists studied them for a century or more, “always bemoaning the fact they could only find females.”

Then a parasitologist who was investigating the parasites the females always have on them discovered that the parasites were the males. The parasitic males were attached to the females, “depending totally on the females for everything,” Palumbi says.

“After they bite the female,” he explains, “their jaws dissolve, and then their brains dissolve, and then their guts dissolve and then their blood systems mesh with the females, and all they are just at the end is a testes that’s there to fertilize the female’s eggs when she’s ready.”

As with many stories, our fascination turns to concern when the characters we like are threatened. And the biggest threat to these characters is humanity.

“The real problem,” Palumbi says, “is that this huge ocean, with all these creatures in it, is not big enough that it is immune to the kinds of changes that we can make in it.”

Overfishing is one serious threat. It disrupts the normal food chains of the ocean. When humans fish heavily, we cause the food energy in the chain to “clump up” at points in the chain where it ordinarily wouldn’t, throwing the ocean life out of balance.

And, of course, there’s climate change — which Palumbi calls a “pervasive, growing and huge problem.” Palumbi says climate change is making the oceans warmer, more acidic and stormier. These problems — already visible now — are projected to grow into the future.

Palumbi compares the process to trying to stop a speeding car. “It’s like you’re booming along … and all of a sudden you see the red brake lights in front of you, and you think, ‘OK, we’ve got to stop.’ But there’s a stopping distance. You can’t stop immediately … That stopping distance for climate change is about 50 years.”

“If we stopped the process by which climate change is happening,” Palumbi continues, “it’s still going to take 50 years or so for the oceans to absorb what we’ve already put into the atmosphere and begin to get better.”

Still, Palumbi hopes readers will share his sense of “guiltless wonder” about the extraordinary life of the ocean. The book, he says, is meant to entertain, to give the readers the sense of “Wow, I never knew that.”

“[T]hese critters out there are not just seafood,” he says. “They live in all the corners of the ocean. They can live and thrive in amazing places with amazing abilities, and … they add to the wonder of our planet.”