‘Aliens of sea’ studied in unique floating lab
Simple sea creatures can regrow their brains and spinal cords
FORT LAUDER DALE, Fla . — Researcher Leonid Moroz emerges from a dive off the Florida Keys and gleefully displays a plastic bag holding a creature that shimmers like an opal in the sea water.
This translucent animal and its similarly strange cousins are food for science. They regrow with amazing speed if they get chopped up. Some even regenerate a rudimentary brain.
“Meet the aliens of the sea,” the neurobiologist at the University of Florida says. They’re headed for his unique floating laboratory.
Moroz is on a quest to decode the genomic blueprints of fragile marine life, like these mysterious comb jellies, in real time — on board the ship where they were caught — so he can learn which genes switch on and off as the animals perform such tasks as regeneration.
The lab is a specially retrofitted steel shipping container, able to be lifted by crane onto any ship Moroz can recruit for a scientific adventure.
Inside, researchers operate a state-of-the-art genomic sequencing machine secured to a tilting tabletop that bobs with rough waves. Genetic data are beamed via satellite to a supercomputer at the University of Florida, which analyzes the results in a few hours and sends it back to the boat.
The work is part conservation. “Life came from the oceans,” Moroz says, bemoaning the extinction of species before scientists even catalogue all of them. “We need a Manhattan Project for biodiversity. We’re losing our heritage.”
Surprising as it may sound, it’s part brain science.
“We cannot regenerate our brain, our spinal cord or efficiently heal wounds without scars,” Moroz notes.
But some simple sea creatures can. Moroz accidentally cuts off part of a comb jelly’s flowing lower lobe while putting it into a tank. A few hours later, the wound no longer is visible. By the next afternoon, that lobe had begun to regrow.
What’s more remarkable, these gelatinous animals have neurons, or nerve cells, connected in circuitry that Moroz describes as an elementary brain. Injure those neural networks and some, but not all, species of comb jellies can regenerate them, too, in three days to five days, he says, if they’re in a habitat where they can survive long enough.
“Nature has found solutions to how to stay healthy,” says Moroz, who also studies human brains when he’s back on shore. “We need to learn how they do it. But they are so fragile, we have to do it here,” at sea.
Two trial-run sails off the Florida coast showed that the shipboard lab can work. Moroz’s team generated information about thousands of genes in 22 organisms, including some rare comb jellies. Moroz’s ultimate goal is
“The amount of new stuff out there is boggling. It’s changing before our eyes.” Gustav Paulay, florida museum curator
to take the project around the world.
Moroz and Gustav Paulay, a curator at the Florida Museum of Natural History, are back from a blue water dive bearing gifts for the lab: clear jars and plastic bags teeming with invertebrates that Paulay describes as “wonky.”
The race is on to keep them alive. Moroz’s three graduate students hoist buckets of sea water and transfer the delicate animals into tanks, stopping to ogle strange finds.
Invertebrates are critical to the food chain, but little is known about them. It’s estimated that thousands of species have yet to be identified. In the oceans, “the amount of new stuff out there is boggling. It’s changing before our eyes,” Paulay says.
But the catch of this day is the collection of comb jellies, officially named ctenophores. (Don’t pronounce the silent “c”.) They made headlines last year as DNA research suggested these animals may represent the oldest branch of the animal family tree, rather than the sea sponges that scientists long have believed held that distinction.
The ctenophores refract light so it looks like they flash electric through the water.
If oceanography and brains seem strange bedfellows, consider: Much of what scientists know about how human neurons and synapses, their connections, form memories came from years of studies using large sea slugs, called Aplysia, such as the one graduate student Emily Dabe gently cups in her hand.
Human brains have 86 billion neurons, give or take. Sea slugs have only about 10,000 neurons, large ones grouped into clusters rather than a central brain, Dabe explains while dissecting the easy-to-spot cells. She brought the animal on board as a control for experiments with the more mysterious creatures.
Yet scientists can condition sea slugs, with mild shocks to their gills, to study that type of memory, Dabe says. Her own research examines the neurochemical serotonin in the animals.
A bit further up the neural ladder, the octopus, with the most complex nervous systems of any animal without a backbone, has about 500 million neurons, says graduate student Gabrielle Winters. There are reports of them learning by watching, although Moroz cautions that’s highly controversial.
Understanding how multiple genes work together to make increasingly complex memories is a building block toward better understanding of brain diseases. It requires working with simple creatures, notes the University of Washington’s Billie Swalla, an invertebrate specialist.