Jellyfish taking over!

Now this is how to popularize science!  Not by scolding us for failing to see how tragically misunderstood sharks and black holes are.  Kids don’t go into science because they want to fight prejudice; they go into science because they want to see monsters.  And here you have it:  an ancient menace, held in check for a half billion years by the brotherhood of post-Cambrian life, now on the move again and carrying all before it.

In Stung!  On Jellyfish Blooms and the Future of the Ocean, biologist Lisa-ann Gershwin argues that after half a billion years of quiescence, they’re on the move:

If I offered evidence that jellyfish are displacing penguins in Antarctica—not someday, but now, today—what would you think? If I suggested that jellyfish could crash the world’s fisheries, outcompete the tuna and swordfish, and starve the whales to extinction, would you believe me?

They can’t be killed!

The question of jellyfish death is vexing. If jellyfish fall on hard times, they can simply “de-grow.” That is, they reduce in size, but their bodies remain in proportion. That’s a very different outcome from what is seen in starving fish, or people. And when food becomes available again, jellyfish simply recommence growing. Some individual jellyfish live for a decade. But the polyp stage survives pretty much indefinitely by cloning. One polyp colony started in 1935 and studied ever since is still alive and well in a laboratory in Virginia.

One kind of jellyfish, which might be termed the zombie jelly, is quite literally immortal. When Turritopsis dohrnii “dies” it begins to disintegrate, which is pretty much what you expect from a corpse. But then something strange happens. A number of cells escape the rotting body. These cells somehow find each other, and reaggregate to form a polyp. All of this happens within five days of the jellyfish’s “death,” and weirdly, it’s the norm for the species. Well may we ask of this astonishing creature, “Sting, where is thy death?”

Some of them are really nasty!

It’s now known that the brush of a single tentacle is enough to induce “Irukandji syndrome.” It sets in twenty to thirty minutes after a sting so minor it leaves no mark, and is often not even felt. Pain is initially focused in the lower back. Soon the entire lumbar region is gripped by debilitating cramps and pounding pain—as if someone is taking a baseball bat to your kidneys. Then comes the nausea and vomiting, which continues every minute or so for around twelve hours. Shooting spasms grip the arms and legs, blood pressure escalates, breathing becomes difficult, and the skin begins to creep, as if worms are burrowing through it. Victims are often gripped with a sense of “impending doom” and in their despair beg their doctors to put them out of their misery.

And they’re taking over the oceans!

How could jellyfish take over the ocean? “One bite at a time” Gershwin says. And there may be no way back. A new balance may be struck, one in which jellyfish rule:

We are creating a world more like the late Precambrian than the late 1800s—a world where jellyfish ruled the seas and organisms with shells didn’t exist. We are creating a world where we humans may soon be unable to survive, or want to.

Why now?  It is only natural that Gershwin concentrates on man-made alterations to the environment–that is the obvious new variable.  On the other hand, is it really true that we’ve created conditions not seen for 500 million years?  Certainly not in terms of CO2 concentration and temperature, but I really don’t know how unprecedented ocean ecosphere disruption or swaths of de-oxygenized seawater are.  And can we really be sure that jellyfish eruptions haven’t happened before?

Anyway, this is a very fun article.  As someone who does a bit of science outreach (although in a very different field), I appreciate seeing this sort of thing done well.  Remember, fellow scientists:  we are explorers bringing back tales of monsters.  That’s the ticket.

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