Dive and Discover : Exp. 8 : Juan de Fuca Ridge : Daily Updates

in Jim Holden’s laboratory on the research vessel Atlantis are not like the everyday varieties that live on our skin, in our food, and around our homes. These unique thermophiles—Greek for “heat loving”—thrive in the super-heated environment at seafloor hydrothermal

vents, where fluids hotter than 200°F (95°C) boil up from deep within the Earth’s crust.

People have known that microbes are special for at least the last 100 years. Today, microbes—particularly thermophiles—are used daily for commercial, medical, scientific, and food industry applications. They help run our cars and help extract oil from wells. They help police investigators at crime scenes, providing enzymes necessary to make copies of DNA artificially in a test tube. They are even used to make sweeteners, like high-fructose corn syrup for soft drinks.

They were probably the first life on the planet 3.5 billion years ago, a time when no animals, plants, or people existed. Think a Tyrannosaurus rex is old?

“Dinosaurs,” says Jim, “have nothing on microbes.”

STUDYING THERMOPHILES
In the last two decades scientists like Jim, an assistant professor in microbiology at the University of Massachusetts Amherst, have studied thermophiles in earnest. On Tuesday, after researchers Deb Kelley and John Delaney collected sulfide rock samples during an Alvin dive, Jim hurried the samples into the ship’s lab. He scraped the thermophiles into glass tubes, each containing different types of thermophile foods. Then he popped them in incubators. These hot, pressurized ovens mimic the thermophiles’ seafloor homes.

Now they are growing. Each morning, Jim holds the tubes up to the light. When the clear liquid inside becomes milky, he knows the population is increasing. From these samples, he hopes to answer some specific questions, such as what food the thermophiles prefer and how different species interact and compete with each other.

Thermophiles caught Jim’s interest during college at the University of Washington in the early 1980s, a few years after oceanographers discovered the first hydrothermal vents at the Galápagos Rift. Fascinated by the new, unexpected life forms found at the bottom of the ocean, he switched his major from architecture to oceanography.

At the black smoker chimneys we sampled at the Mothra hydrothermal vent field, the microbes cling to minerals within the sulfide rock. This rock is porous, like a sponge, so hot fluids from the vents shoots through it, delivering food to the thermophiles. It’s not a complicated diet: hydrogen for energy, carbon dioxide for carbohydrates, plus a pinch of sulfate, nitrate, or iron for respiring, the microbial equivalent of humans breathing oxygen.

When Jim returns to Amherst in two weeks, he will take the thermophiles with him to continue monitoring their growth. He wants to sort out the differences in hundreds of types of thermophiles, to learn their individual characteristics. Otherwise, he says, lumping all of them into one category is like saying that all Americans eat only pizza.