Ocean Floor Ecology
6:28 am
Fri June 8, 2012

Deep-Sea Stowaways Get A Leg Up From Scientists

Scientists working more than a mile underwater off the Washington coast have learned that the bottom of the ocean is surprisingly vulnerable to human disturbance. Even from scientists. KUOW's John Ryan reports from Seattle.

If you drive east from Seattle 300 miles, you'll be on the outskirts of Spokane. Head due west from Seattle the same distance, and you'd find yourself far out to sea, floating above the Juan de Fuca Ridge.

That ridge in the bottom of the Northeast Pacific Ocean is home to the bizarre ecosystems known as the Endeavour Vents.

That gurgling is super-heated, super-pressurized water blasting out of the vents. University of Washington researchers recorded the sounds. The vents look like tall chimneys billowing black smoke.

The Endeavour Vents were only discovered in the 1980s, by scientists crammed inside a deep-sea vessel called the Alvin. Ray Lee of Washington State University is one of the few people who have seen these vents up close. He says the biggest hazard working so far underwater isn't what you might think.

Lee: "The danger of being in the Alvin is not dying from drowning. A leak that springs will probably be some type of pinhole. That pinhole spraying around inside the submarine is not going to drown you so much as it's going to probably sever body parts."

Lee studies animals like tubeworms, snails and crabs that flourish at the vents. He says one animal is dominant: a type of snail called a limpet.

Lee: "They are the most abundant organism in these Northeast Pacific vents. They blanket the vent area. They're literally stacked on top of each other."

Organisms at the vents are specially adapted to the crushing pressures of the deep. They don't do so well if you bring them to the surface. Bruce Shillito studies deep-sea life at Sorbonne University in France.

Shillito: "Most deep-sea species only survive a few hours at most at atmospheric pressure after they have been collected for scientific study. This is why pressurized cells are needed to keep them alive in the lab."

The difference between our world and their world is hard to fathom. Shillito says in the deepest ocean,

Shillito: "The pressure is equivalent to a buffalo or a rhinoceros standing on one of our fingernails."

The sun never penetrates to the depths. So the food chain at the vents isn't fueled by the sunlight. It runs on sulfurous chemicals boiling up from the earth's crust. Microbes at the Endeavour vents live in water at the insanely high temperature of 250 degrees Fahrenheit.

One Alvin expedition returned from this bizarre underworld with 38 limpets of a species they'd never seen at Endeavour. Here's Ray Lee.

Lee: "That was a surprising thing because this particular species of limpet has only been found on the Gorda Ridge."

That's 400 miles to the south, closer to the Oregon-California border. The Alvin had visited that site a day before.

After some genetic and chemical analysis, the scientists reached an unhappy conclusion. They had contaminated the Endeavour site by introducing a new snail and whatever pathogens it might carry with it.

In the latest issue of the journal Conservation Biology, the researchers explain that the limpets probably hitched a ride inside the ridges of the Alvin's underwater vacuum hose.

Lee: "It was actually some hose that came from a pool supply store. So it looks just like the type of hose you would have on your home vacuum cleaner."

The hose on the Alvin sucks up samples from the sea floor. The crew on board the Alvin's mother ship would clean the Alvin after each dive. They learned the hard way that they need to get all the nooks and crannies.

Scientists don't know yet whether the surprisingly tough little limpets are proliferating at their new home. But they expect this paper to make a splash in the research community. John Baross is an oceanographer at the University of Washington.

Baross: "Everyone will clean their sampling devices to make sure that there's no larvae or organisms present in there. I don't think this kind of accident will happen again."

Ray Lee with WSU is concerned that mining companies working the deep sea floor won't bother to clean stowaways from their gear the way scientists will. But John Baross says introducing new species is the least of the concerns when it comes to deep-sea mining.

Baross: "The mining industry wants to go into international waters where many of these hydrothermal vents are and dredge for minerals. That's essentially destroying those environments."

Though the Endeavour Vents are due west of the Olympic Peninsula, they actually sit inside Canadian waters. And Canada has set those vents aside as a marine protected area. Canadian companies are pursuing their deep-sea mining plans elsewhere in the Pacific.

Copyright 2012 KUOW