Hot Spots Under the Sea
Strange
things happen under the ocean.
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| John Baross (left) and a co-worker study a natural chimney that has been lifted to the deck of a ship. |
Dr. John Baross lowers his body into a tiny submarine called the Alvin. As always, he feels a tingle of excitement. He is bound for one of the hot springs that lie along a mountain range called the Juan de Fuca Ridge. Near Canada’s Vancouver Island, this ridge lies one and one-half miles under the surface of the ocean. “Today,” he thinks, “may be the day that I find some new form of life.”
All along the Juan de Fuca, cracks in the ocean floor allow water to seep deep down into the Earth’s crust. The ocean water is heated as it trickles down over hot rocks and then is forced back up through hot springs.
The water that gushes out of the hot springs, or hydrothermal vents, may be more than three times the temperature of boiling water at sea level. But at the bottom of the ocean, the water doesn’t boil—because it can’t. The water pressure is too great for any gas bubbles to form and escape.
The super-heated water contains hydrogen sulfide (the stuff that makes rotten eggs smell bad), dissolved metals, and other chemicals. The water often looks like smoke, so scientists call these vents “smokers.” Often, a chimney of rock forms around the vents.
Most living things would be killed by the water’s high temperature and toxic mix of chemicals. But the water gushing from the vent teems with microscopic life. Some of these heat-loving microbes are bacteria. Others are archaea (ar-KEY-ah), which are thought to be one of the oldest forms of life on Earth. Both the bacteria and the archaea have developed special proteins that help them live under such harsh conditions.
Unlike life on the surface of the Earth, which depends on sunlight for energy, the vent microbes depend on chemicals in the water. Some of the microbes actually live in or around the vents. Dr. Baross thinks that some of the archaea were swept out of their home deep under the ocean floor.
Inside
the Alvin
Dr. Baross shares a small space inside the Alvin
with another scientist and with the pilot of the sub. It
is early in the morning. They will be crammed together until
late that afternoon. They brought their lunch. Each of them
has a peanut-butter-and-jelly sandwich, a candy bar, and
an apple. “We have to watch what we eat and drink,”
Dr. Baross explains, “because there is no bathroom
on board.”
The Alvin begins its two-hour journey to the deep-ocean floor. At first, the scene outside the Alvin’s tiny portholes is familiar. There are large and small fish, a stingray, or perhaps a school of dolphins. As it continues to sink, the sunlight gradually fades until there is no light at all. For the next thirty minutes, the Alvin is surrounded by a cloud of creatures that glow and flash like fireflies.
Slowly, the explorers leave the starry creatures behind, and everything is dark. They turn on the headlights and finally reach the ocean floor. It is easy to understand why scientists once believed the bottom of the ocean was nearly as lifeless as the moon. Most of the sea floor is flat and bare.
The
Ocean Floor
It is cold down there. The Alvin is not heated, and
Dr. Baross shivers. He is glad he dressed warmly. Outside
the Alvin, the ocean is pitch-black. The pressure
outside the sub is 275 times that at sea level. If the Alvin
weren’t made of a super-strong titanium metal, it—and
its crew—would be crushed.
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| This twenty-foot-tall chimney is part of a hydrothermal vent. Microorganisms live inside it. On the outside live bigger creatures, such as the orange spider crab near the bottom. |
Ahead, something tall looms in the murky darkness. It’s a chimney—the tallest one Dr. Baross has ever seen. The crew spends the entire day exploring the structure. Ledges jut out all along the chimney, like giant shelf fungi growing on a tree. Super-hot water pours from openings below the shelves. “It is like seeing the Empire State Building on the bottom of the ocean except with hundreds of smokers all over it,” exclaims Dr. Baross.
The area around the chimney is home to a menagerie of strange animals. Two-foot-long worms that look like giant tubes of red lipstick slowly wave about. Spider crabs scuttle to and fro. Inside the chimney live palm worms, with tentacles that look like palm leaves. They live at temperatures that would cook most other animals.
Using the Alvin’s robotic arms, the pilot gently picks up some of the creatures and places them in special boxes attached to the sub. They will be carried to the surface for later study.
The pilot measures the temperature and collects water samples inside each smoker. He sometimes knocks off pieces of the chimney and places them in a box. Dr. Baross will look for microbes in all of these samples. He and the other scientist use special cameras to record the whole scene. “You’re seeing new things almost all of the time,” he explains.
Back
to the Ship
Finally, it is time to make the long journey back to the
surface. Once on board the ship, there is a lot of work
to do. Dr. Baross and the other scientists want to study
their new finds while the creatures are still alive.
Dr. Baross begins his work by cutting open some of the worms found inside the smokers. He’s looking for heat-loving microbes inside the gut of the palm worm. These creatures love to eat microbes. This research is hard work to do on a moving ship, especially when the ocean is rough.
Once Dr. Baross gets microbe samples from the worm’s gut, he tries to grow them in his lab on the ship. He does the same for the microbes in the water samples. Many of the microbes Dr. Baross studies live by using dissolved hydrogen sulfide, which most of us know as a smelly gas. “You get used to it,” he says. “It’s the smell of growth, and that means you’ve isolated an interesting organism.”
Dr. Baross and the other scientists on the ship often work all night long. They go to bed hoping that when they wake up, they will find something unusual growing in the lab. It may be another form of bacteria or archaea—new to science—from the hot spots under the sea.
