A chance observation about warts on a pea plant led a trio of teenagers on a three-year mission to solve the world food crisis. Their perseverance earned them top honors at the annual Google Science Fair in Mountain View, California.

Emer Hickey, 16, Ciara Judge, 16, and Sophie Healy–Thow, 17, of Kinsale, Ireland won the top prize in their age category plus the Grand Prize at Monday night’s awards ceremony in Palo Alto, California. Each walked away with a $50,000 college scholarship, a 10-day National Geographic Expeditions trip to the Galapagos Islands, a $10,000 grant for their school and other prizes. Scientific American co-sponsors the awards and editor-in-chief Mariette DiChristina serves as head judge.

“I’m in shock, I didn’t think we would win,” said Judge, speaking through tears after being showered with confetti at the awards ceremony.

From the beginning, adults told the three friends that their scheme for boosting crop yields in barley and oats wouldn’t work. But the trio refused to give up.

It all started when Hickey and her mother, Francis, began gardening. They pulled up a pea plant and saw that the roots were covered in nodules. “We thought we were killing it,” said Francis Hickey.

Emer brought the plant to her science teacher, who explained the nodules held beneficial bacteria known as rhizobia. The microbes convert nitrogen in the atmosphere into ammonia and other compounds that help the plant thrive.

At the time, the students' geography class was studying the world food crisis, and an idea for a science project quickly germinated. “We became really interested in what this bacteria can do and what people haven’t done with it so far,” said Healy-Thow.

They set up a laboratory in a spare bedroom of Judge’s home, hand-built equipment for it and went to work. They started with 12 seed trays and expanded into a field trial that now holds 3,600 seeds.

After conducting more than 120 experiments and manually recording more than 120,000 measurements, Hickey, Judge and Healy-Thow found that rhizobia sped up the rate at which barley seeds germinate by 50 percent and increased crop yield by as much as 74 percent. The exact mechanism by which the microbes help the cereal crops, which do not form nodules like legumes, is still unknown.

“It has a lot of implications,” said Hickey. “By the year 2050 we actually need 50 percent more food just to feed everyone.” She says the bacteria may also reduce the need for chemical fertilizers, which can harm the environment.

T.H. Culhane, a National Geographic Explorer and Google Science Fair judge said the team’s methodology set them apart. “It was big data in small hands,” he said.

The group now hopes to conduct more in-depth studies to understand how and why the bacteria help barley grow. “We’re not even finished yet,” said Hickey

More to explore:

Find more details about their study at the Google Science Fair Web site.

Check the trio's YouTube channel for updates on their work.

Image credits: Anna Kuchment