What was it like being in the Alvin?

This was in 1989, midway through my two-year postdoc at the Massachusetts Institute of Technology, where I worked with John Edmond — a co-discoverer of the first low-temperature hydrothermal vents on the 1977 Galápagos cruise. Edmond and I went back to TAG, and this time, thanks to Alvin, I got to see a black smoker up close. Alvin had been to this area before, but the pilot couldn’t figure out a safe way to get close enough to obtain good samples. The top of a black smoker is like a fire hydrant with the top knocked off. There’s a strong flow that you could get swept up in, and the water coming out can be up to 400 degrees Celsius.

The trick Edmond and I came up with was to get down deep, starting at the base of the chimney where things are relatively calm, and then cautiously move upward. That’s how we were able to get the first really good samples from that site — water laden with sulfur, iron, copper, zinc and lead, which is what makes it look black. That was the first successful sampling from a hydrothermal vent anywhere in the Atlantic.

Just being inside the Alvin was an experience. Only two scientists and a pilot can fit in it, and you’re down for just eight hours. Time passes quickly because it’s all so overwhelming. The chances are great that you’re seeing something no one else has seen before. And getting so close to a black smoker was incredibly exciting. You can’t drive your car right up to a hot spring at Yellowstone. And this spout at the bottom of the ocean, unlike Old Faithful, has been going off continuously for thousands of years. That speaks to the power and energy locked up inside our planet.

During my two years at MIT, I developed a passion for studying hydrothermal vents. The question I grappled with was: If I leave and return to the U.K., how can I play a role that is new and original?

How did you intend to contribute to this area?

Remember that when I had started graduate school just a few years before, it was still widely believed that there weren’t hydrothermal vents in the Atlantic. We knew that wasn’t true, but I wondered how many hydrothermal fields there were on this planet, and what were the most efficient ways of searching for them.

I realized that although a vent itself is typically only about the size of a football field, the plume coming out of it is like a mushroom cloud that rises into the water column and expands. Even after getting diluted by a factor of 10,000, the concentrations of iron, manganese and other metals are still 100 times greater than in ordinary seawater. We could find evidence of these plumes without doing any chemical measurements simply by using optical sensors to measure the cloudiness of the water. And because of the way the plumes spread, these features could sometimes be detected from hundreds of kilometers away.

After finishing my postdoc in 1990, I returned to the U.K., taking a job at the National Institute of Oceanography in the village of Wormley. I no longer had access to a submarine like Alvin, but a group at the institute had just developed a towable instrument that used sonar to map the seafloor. I said that if we put my optical sensors on that vehicle, I could figure out where all the hydrothermal activity is.

The first time we used this approach, we found six new vent sites in the Atlantic, where only two had previously been known. It was no longer a matter of stumbling upon things by accident; we could go about it systematically.