It was a typical onboard encounter: two strangers, adjoining airline seats, small talk to pass the time.
They talked about what they did. Virginia Armbrust, a plankton ecologist at the University of Washington in Seattle, described the critical roles plankton play in sustaining life on Earth. At which point, her fellow traveler asked a disarmingly simple question: "So how are they doing?"
It hit like a jolt of mid-flight turbulence. Dr. Armbrust recalls she didn't have a good reply; no one really knows how well the carbon-grabbing, oxygen-making organisms are doing. It marked a turning point in Armbrust's thinking. Answering that question "became my goal," she says.
Armbrust and an international team of researchers took a significant step toward that goal this fall when they published the genome - a genetic parts list - for a tiny, glass-encrusted plankton known as a diatom.
In an office next to Armburst's, Gabrielle Rocap leads one of several teams worldwide conducting similar studies on more of the ocean's smallest inhabitants. Their aim: to reach the day when scientists can take the biological pulse of the ocean by interrogating the genes of the tiniest organisms that live there.
Such data would help researchers anticipate how environmental change - everything from land-borne pollution to global warming - affects ocean ecosystems and the atmosphere.
"We're looking for canaries in the coal mine," Armbrust says. Many people focus on larger, charismatic creatures such as whales and other marine mammals. "But you'd like to look at phytoplankton. They're at the base of the food web and they respond to changes immediately. If you see changes in marine mammals, it's too late."