The extreme heat of hydrothermal vents even 2,500 meters under the sea resembles the conditions life likely endured when it first emerged billions of years ago. Credit: Jeremy Rich The research vessel Atlantis sailed due south for two days to reach the spot where lines drawn south from Denver and west from Costa Rica would cross. The 260-foot ship stopped at that point on a sunny Nov. 5 morning. The next day, amid squalls of rain, the ship sent precious cargo overboard: a robotic instrument that after years of planning, could now be deployed to examine the hydrothermal vents of the Pacific Ocean floor.
Jeremy Rich, assistant professor of ecology and evolutionary biology at Brown, described that Vent-Submersible Incubation Device (Vent-SID) as something of a multishelved lunar lander. It took nine hours to descend 2,500 meters to the bottom—possibly, Rich said, swaying its way down like a falling leaf despite its payload of bulky batteries, electronics and other gadgetry.
The device was designed to gather and incubate samples of the microbes that inhabit the fluids of hydrothermal vents. But before Rich and his colleagues could get the valuable data they had sought so long, he and two others would have to go in after it, find it, and move it into position more than a mile beneath the churning sea.
For the sake of science
Rich and Brown postdoctoral scholar Nuria Fernandez-Gonzalez are on board the Nov. 2-26 expedition, led by Woods Hole Oceanographic Institution scientist Stefan Sievert, to study the metabolism of the vent microbes, which process carbon dioxide, oxygen, and nitrogen. Scientists from around the United States, and China, Germany, and Japan are running several projects, but Rich and Fernandez-Gonzalez are particularly interested to learn how much the microbes rely on denitrification—converting nitrogen as they encounter it into the nitrogen gas that makes up 80 percent of the atmosphere.
“If denitrification turns out to support a significant fraction of microbial activity, it would provide an important step forward in understanding how microbes at vents live,” he said. “As [the] microbes are at the base of the food chain at hydrothermal vents, our study will provide fundamental knowledge about how these amazing ecosystems function.”
Characterized by their extreme heat, the ecosystems of hydrothermal vents resemble the conditions life likely endured when it first emerged billions of years ago.
A dream-like descent
On Saturday Nov. 8, after a technical delay, Rich, pilot Phil Forte, and microbiologist and principal investigator Craig Taylor, dove in the submersible craft Alvin to find the Vent-SID, grab it with Alvin’s arm, and deploy it at the right location in a field of vents.
