Advisor: Lauren Mullineaux and Tim Shank
Research interest: Dispersal of animals to and from hydrothermal vents.
Expected graduation: 2006
On her 22nd birthday, Diane Poehls received a most unusual present: a chance to spend the next day under 2500 meters (1.5 miles) of seawater. On January 18, 2002, Diane made her first dive in Deep Submergence Vehicle Alvin, joining WHOI Assistant Scientist Tim Shank and Pilot Pat Hickey on a voyage to the famed hydrothermal vent field at 9° North on the East Pacific Rise. They observed black smokers, shrimp, mussels, and haystack-like clusters of riftia tubeworms, while collecting animal and water samples. With that dive, Poehls realized a childhood dream.
She was researching for a 7th grade science project when she found a National Geographic article about a seafloor eruption at 9° North. "I saw the photos of this strange world miles and miles below the surface of the ocean," Poehls recalls. "It was so different from anything we were used to. I was intrigued by how it looked like a barren desert in places, and yet there were pockets of these absolutely fascinating animals."
She went on to take a marine biology class in high school, study aquatic biology in college, and pursue a doctorate in biology in the MIT/WHOI Joint Program. At age 24, she has already made two Alvin dives and spent 135 days at sea on five oceanographic expeditions. In the summer of 2002, she was one of five Americans to spend a month in the North Atlantic on R/V Akademik Keldysh, a Russian research vessel and tender to the Mir 1 and Mir 2 deep submergence vehicles. And she plans to make more visits to 9° North, as her proposed thesis research focuses on the kinds of creatures who make their homes there.
She is interested in the dispersal of larvae in hydrothermal systems. Simply put, she wants to understand how species move and migrate from one vent site to the next, a process that has implications for the survival of species in an world where hydrothermal vents may be spewing today and dormant in a month or a year. "Vent environments are ephemeral," she notes, "and these animals and their offspring must somehow get from one patch to the next, sometimes traveling many miles between vents."
As soon as vents were discovered, biologists recognized that dispersal was an essential yet unknown component of the function of the communities," says Lauren Mullineaux, a Senior Scientist in the Biology Department and an advisor to Diane. Population geneticists generally assume that larvae arrive at new vents from a large, well mixed gene pool, Lauren notes. "Diane knows that dispersal doesn't work this way in shallow or coastal systems, and it probably doesn't work this way in deep-sea vents. Her work will help define how vent larval dispersal deviates from the larval pool, and will evaluate the consequences for vent populations."
One of the most controversial and interesting questions in modern biology is how populations are connected. "Vents pose a special challenge and opportunity to learn about connectivity and dispersal," says Diane. "These grandiose communities persist despite constant environmental change and extinction. If you accept that fragmentation is a risk to the survival of a species, then vent organisms should be extinct or should never have existed. How do they do it? What mechanisms transport larvae? How does dispersal differ between species? There are so many questions."
Answering those questions is going to require a lot of long hours in the laboratory and a few more trips to the ocean floor. Diane won't mind.
"Going to the sea floor is like taking a trip to another world without leaving Earth," she says. "And it is a far more interesting trip. It sure beats the pictures that we've recently seen from Mars, and it doesn't cost billions and billions of dollars to go there."
Originally published: February 24, 2004