SCIENCE -- August 23, 2012 at 6:12 PM EDT
Throngs of Dangerous Jellyfish Stings Caused 'Intense, Ripping Pain' for Nyad
This photo shows three of the jellyfish that Nyad encountered during her swim. To the left is a carybdeid cubozoan, a type of box jellyfish. And to the right, almost out of frame, are two olindias. Photo by Angel Yanagihara.
During her 51-hour attempted swim from Cuba to Key West this week, Diana Nyad battled extreme exhaustion, severe sunburn, strained muscles, powerful storms and circling sharks. But what really ground the 103-mile trek to a halt, she said, was the jellyfish.
As she swam through the nights, the creatures stung her hands, forehead and lips, causing what she described as "intense, ripping pain." The stings also brought on tremors, chills and fuzzy thinking, Nyad told the NewsHour's Margaret Warner in a phone interview on Tuesday, while still on the boat.
"I swam through three nights, and each night was stung badly," Nyad said. "It's one thing to be stung and just have some searing pain on your skin that you can breathe and count your way through and get over it. It's another thing to have an animal sting you and go into paroxysms, and have your lungs and heart slow down."
This was despite a carefully pre-planned, three-pronged strategy of detection, prevention and treatment to prevent against jellyfish stings. The plan involved a 42-foot motor cruiser positioned ahead of Nyad with underground cameras, a full-body protective swimsuit that covered everything but Nyad's mouth and hands and shark divers who also watched for jellyfish.
It was Nyad's fourth attempt to swim from Havana, Cuba to Key West and to cross a wild and dangerous stretch of ocean without a shark cage. She was just shy of her 63rd birthday.
Before and during the swim, Nyad's team worked closely with Angel Anne Yanagihara, jellyfish expert and assistant research professor at the University of Hawaii's Pacific Biosciences Research Center. Back home, Yanagihara had tested different swimsuit fabrics for Nyad in the most hands-on way possible: by wearing various sample suits while exposing herself directly to powerful jellyfish stings.
But out on the open ocean, things don't always go as perfectly planned. The monitoring system encountered technical problems, shark divers suffered their own stings and the jellyfish found their way to Nyad's only exposed skin: her lips.
"How could it be that a tiny little animal that has a tentacle no bigger than a strand of a hair...could be out there in this vast wide ocean," Nyad said, "and I'm wearing a suit and creams and repellant and the only square inch of my entire body that's open and exposed is my lips, because I've got to breathe. How could that tentacle find those lips?"
At times during Nyad's swim, the jellyfish clustered in throngs so thick, the stings were almost constant.
"Shark divers reported that her hands were crashing through a whole sea of olindias and shredding them with her hand," Yanagihara said. "The shark divers swimming with her were having to dodge these. I just can't even describe the level of power that she presents out there."
At one point, Nyad swam to the side of the boat, yelling in pain, with a tentacle stuck between her fingers. Yanagihara pulled out the tentacle, and within seconds had inspected the cells under a microscope to determine the source. She identified it as a box jellyfish, one of the most venomous and painful jellyfish in the water.
The team dabbed onto her stings a hot treatment that Yanagihara had developed to inhibit the toxins in box jelly venom, and used a technique to gently wipe off any other undischarged cells from her hand. And for the next 10 minutes, they monitored her breathing, heart rate and pain level.
"I was extremely, extremely, extremely concerned," Yanagihara said. "People have said that on a scale of 1 to 10, the sting of a box jelly on bare skin is a 100. I thought the swim was over right then."
But Nyad rated the pain level a 6, and within 10 minutes, it had dropped to a 2.
Throughout the trek, Yanagihara identified six different species of jellies, in some cases by examining the specimen directly; in others, by collecting cells using sticky tape from the site of the sting.
Depending on the species, one jellyfish can have anywhere from a few to hundreds of tentacles. Each of these tentacles contains thousands and thousands of cells, said John Finnerty, director of the Boston University Marine Program. Inside each cell is a fluid sac filled with venom.
"Think of it as an IV bag," Finnerty said. "It's a fluid bag, it's tied to a tube, and the tube is connected to a needle." But the tube is inverted, he said. That is, until the organism stings.
Jellyfish contain what Yanagihara describes as spring-loaded injection systems. When triggered, the tube and needle explosively shoot out, injecting venom into prey or a potential predator.
The tube, she said, exhibits the biophysical characteristics of surgical steel. Like a bullet, it shoots out and pierces human skin. "It pierces through with this hollow injection device, from which venom is pushed down through the propelled tubule and into the victim or the prey."
The sacs of venom are called nematocysts, and they are poisonous enough to cause cardiac arrest and in the most severe cases, death.
In the 34 years since Nyad first swam from Cuba to Key West in 1978, the ocean has changed, she said. "The story of how jellyfish have proliferated in the world's oceans today - it's going to be the biggest story of the oceans," she told the NewsHour on Tuesday.
"Without a doubt, the ocean's warmer now," Finnerty said. "The ocean's more acidic than it was then. Depending on where you were, there could be more contaminants in the ocean and more algal blooms."
And in warmer conditions, jellyfish thrive. As the ocean water has warmed, the organisms have been found farther north in the Atlantic than ever before. In Japan, fisherman have reported hauling up nets full of jellyfish. One giant jellyfish sunk a 10-ton fishing boat.
Studies have shown that overfishing, warmer temperatures and other human-caused variables "have stacked up in favor of the jellyfish," Yanagihara said, and some think the oceans are reverting back to a state resembles the primordial sea that existed even before invertebrates were on the planet, she said.
However, Yanagihara said, more data is needed to understand definitively how much the ecosystem has changed.
It was a powerful, life-threatening storm that caused the team to hoist Nyad out of the water and into the boat. But the jellyfish factored greatly into her decision not to return to the water and complete the swim. The nightly battle of the jellyfish was painful and shaved off time.
"All the treatment and body coverage creates a lot of drag for her as a swimmer," Yanagihara said. "It wasn't the purity of an endurance effort for the sake of effort, it was again shooting the dice with what was going to be another hard night."
The swim, she added, could be seen as a wake-up call for a changing ocean ecosystem.
"It shows us that despite the will, determination and discipline from one of the best athletes on the planet, we really have to be humbled by what we can and what we cannot do."