Several years ago, feeling in over his head, new teacher Ben Thwaits turned to his love of nature photography to help reach his students, young people grappling with mental illness.

Using grant money to put cameras in their hands, Thwaits said he found that the young residents of Northwest Passage, a treatment center based in Frederic, Wis., began using their photos to interpret the challenges of their lives.

Students who had spent hours on therapists' couches and struggled with addiction and thoughts of suicide began to understand themselves through the pictures they took at national parks and nature areas across the country.

Then, a couple of years ago, Thwaits got a phone call from a professor at Northland College in Ashland, Wis., an aquatic ecologist. Thwaits said he suggested taking their work to a new level: "Take your program and sink it. Let's go underwater."

They started donning wet suits and snorkels and going under the St. Croix River, then Lake Superior and, recently, the Caribbean.

The water has not only opened new vistas, Thwaits recently told a lunchtime gathering at the Lowell Inn in Stillwater. Going underwater has helped his students find a new calm and new hope.

"There is a therapeutic power from being in the water," he told members of the St. Croix Valley Foundation. "The takeaway is that water is medicine."

He started the In A New Light nature photography program at Northwest Passage in 2010.

Since then, his students' work has been viewed by millions through nationwide art exhibitions, on PBS, and even on the big screen at Twins games.

The project has received funding from Wisconsin Sea Grant, the National Park Service and the National Park Foundation.

No longer defined by their illness, Thwaits said, his students have discovered abilities they never knew they had. Alumni have moved on to college and jobs, many using the skills they've learned through In A New Light.

He shared some of his students' reflections of the program in his presentation.

"I came to Passage struggling to see the good in myself," Rachel, 15, wrote. "My depression and anxiety overtook me, which led me to become a threat to my own life. When I first started underwater photography, it was almost instant relief. Every time I put my face in the water, all of my worries washed away."

Jonathan, 17, said he is amazed by what he's discovered under the water — like a freshwater sponge.

"There are so many beautiful aspects of life that we never see and we never know about, unless we look.

"Take this sponge, for example," he said. "I was really surprised to find out that there were sponges in freshwater ecosystems, and now I've had an opportunity to capture their beauty to share with the world."

And Ndolo, 16, said, "Underwater photography not only gave me a way to express my emotions; it gave me a motivation, something to work towards and look forward to. Let's be real here … although I love school, getting out of bed to swim with the fish is a cooler way to learn than sitting in a classroom."

James Walsh • 651-925-5041