Photo by Erin Towns.
Toolik Field Station lies in the northern foothills of Alaska’s Brooks Range, on the
shores of Toolik Lake, in August 2025.
By Haley Dunleavy
Toolik: World’s largest Arctic research station
On a July day in 1975, a team of six scientists based at the top of Alaska drove the newly finished Dalton Highway, searching for a deep, inland Arctic lake to compare to their coastal study lakes. After sampling a few sites for a spot that would be deep enough to have overwintering populations of fish, they settled on Toolik Lake, located in the northern foothills of the Brooks Range. The field crew set up their tents alongside a pipeline construction camp and began the long history of research at Toolik Lake.
Half a century later, the original site, now known as Toolik Field Station, has grown to become the world’s largest Arctic research station, with a maximum population of 155 residents at one time. Thirteen labs, six dorms, three rows of tented lodging, a year-round dining hall and over 30,000 research plots annually support upward of 500 scientists, students, support staff and educators. The station serves as the site for long-standing programs like the Arctic Long Term Ecological Research program, Arctic Observing Network, International Tundra Experiment and National Ecological Observatory Network. Research findings, highlighted in over 2,000 publications, have contributed greatly to the global science community’s understanding of how Arctic ecosystems function. More recent research efforts at Toolik have branched out to different fields, including space weather and bedrock geology.
For many, the first experience at Toolik Field Station in Arctic Alaska starts with a hike up the research boardwalk. The 2-mile loop crosses the Toolik Lake inlet stream and heads uphill as it transitions from water-logged tundra to dry, rocky heath. It’s a walk through four decades of science at Toolik.
It’s also a vivid memory for Rebecca Hewitt, a former doctoral student at UAF and now an assistant professor at Amherst College in Massachusetts. In 2009, Hewitt first traveled to Toolik in the middle of Arctic summer, when often the only things clouding the midnight sun are the incessant, whining hordes of mosquitoes.
A technician with Toolik Field Station’s Spatial and Environmental Data Center wears a bug shirt to fend off mosquitos while measuring soil properties in the summer of 2020.
That night, she joined researcher Gus Shaver, who established many of the first experiments at Toolik, on the boardwalk. Arctic ground squirrels chirped underneath the wooden boards. The astringent yet floral scent of blooming Labrador tea filled the air.
Shaver walked Hewitt through research plots that he started with others in 1989. Experimental treatments were denoted by worn metal tags on wooden stakes: warming, shade, fertilizer. While pointing out which plant species win with a warmer tundra, he gave her some advice about her bug spray.
“I’m pretty sure Gus pulled out the 100% DEET in a bottle with all the writing disintegrated off,” she said, laughing and remembering her eucalyptus spray. The “natural” option is often ineffective against Arctic swarms, which can be so thick that they sound like raindrops bouncing off jackets.
A graduate student samples mycorrhizas, or beneficial fungi, on plant roots near Toolik Lake in August 2024.
Hewitt had no idea then that she’d return in seven years to contribute her own ecological findings to the experiment’s legacy, studying tundra plants’ beneficial fungal partners known as mycorrhizas.
For 50 years, scientists have researched sites at UAF’s Toolik Field Station. Sitting in the northern foothills of Alaska’s Brooks Range, the station is operated by the Institute of Arctic Biology with support from the National Science Foundation. Established in 1975, it’s grown from a temporary summer field camp to a world-renowned year-round research facility, housing around 500 scientists annually.
About 75 students come to Toolik every year as part of research teams, most of them between May and September. They stay for months at a time, forming the core of field teams that venture out daily to collect data from nearby tundra, lakes and streams. Yodeling calls of yellow-billed loons and fields of fluffy tussock cottongrass provide the backdrop to full days of field and lab work.
These first field experiences at Toolik can be transformative for students and early-career researchers. It’s a period when aspiring scientists can build research skills, develop confidence, boost their connection to their study system and find pathways to pursue their research interests. These elements make Toolik a place where students and postgraduates launch careers in Arctic science.
“There's something that experiential learning provides that is really hard to recreate outside of a given place,” Hewitt said. “It shaped my investment and connection to what I’m doing.”
A landscape that sinks its hooks in you
Tom Glass still remembers the “mind explosion moment” when he heard that wolverines live near Toolik.
Glass, a research associate with the Geophysical Institute, first came to the station in summer 2015 as a technician on a grayling study. He had earlier researched wolverines in the Mountain West.
“It hadn't occurred to me that wolverines would exist here,” he said of Toolik. “I was immediately filled with all these questions. How did they make it out here? Where do they den? What do they eat? Do they ever go out on the sea ice?”
Glass returned to Toolik the next spring, joining a project on wolverines with UAF and the Wildlife Conservation Society, and has been back nearly every year since. He earned his Ph.D. from UAF in 2022.
“[The landscape] sunk its hooks in me and has given me years worth of questions to pursue as a scientist,” Glass said.
A wolverine traverses the tundra in Arctic Alaska.
Between 2016 and 2022, some of Glass’s most exciting findings came from studying the tundra near Toolik “through the eyes of a wolverine,” he said. Following wolverines, he discovered that they opportunistically use temporary permafrost caves for dens. He also found that in winter they eat fish frozen in pools.
“Those weren't findings that came from elaborate analysis,” he said. “They were these surprising observations that made me stop and just stare at them for a while, scratching my head.”
A muskox makes a rare visit to Toolik Field Station in August 2024.
The intimate experience of the tundra offered by Toolik often hooks scientists like Glass. Red foxes and arctic ground squirrels weave between buildings at the station. Caribou and muskoxen can be seen while driving to field sites. The Brooks Range towers ever-present across the southern horizon, except for the days when Arctic fog has settled thickly across the tundra. Double rainbows are almost as common as mosquitoes.
The connection to the environment also grows from meeting its challenges — like carrying a fish cooler packed with soil samples across tussocks after a 10-hour day, only to find your truck has a flat tire.
Still, Hewitt recalled, the landscape rewards one.
“There were these glorious evenings with that amazing light late at night,” she said. “It just felt like magic up there.”
Fall colors begin to emerge in tundra plants at a research site near Galbraith Lake in August 2024.
A community that thrives together
After finding evidence of wolverines denning in underground permafrost caves, Glass needed more information on permafrost thaw.
“I was able to come back to Toolik, sit in the sauna and have a conversation with a permafrost scientist,” Glass said.
That illustrated another type of support created by Toolik’s remote location: a strong sense of community. Experts across an array of fields overlap, like a living encyclopedia of Arctic science.
Graduate students work with high schoolers from Oregon State University’s Upward Bound program to sample cottongrass for genetic analysis in August 2023.
Glass ended up publishing a paper with the permafrost researcher. He also collaborated with a film crew to share his wolverine findings in a BBC nature documentary.
Hewitt’s work on plant-fungal partnerships benefited from similar collaboration. She had no money for a helicopter to reach a tundra wildfire scar she hoped to visit. So scientists with other projects at the burn offered her an empty seat on several flights.
“It was really through their generosity and openness to trying to make as much science happen with the available resources that I was able to have this project out in the burn,” Hewitt said.
In addition to learning from researchers, students at Toolik have access to dozens of ongoing experiments at the station. In 2016, Hewitt returned as a postdoctoral researcher, working in the exact plots that she toured her very first night at the station.
“It was foundational to be in a community where people are open to saying ‘yes’ and be collaborative in that way,” she said.
Randy Fulweber, who’s worked with Toolik’s geographic information systems and remote sensing department since 2008 after completing graduate coursework at UAF, said the day-to-day living and shared spaces at Toolik make it easier for early-career scientists to connect.
“It just lowers any kind of barriers that may exist in a traditional university setting, where someone may be in a different department in a different building on a different side of campus,” Fulweber said. “At Toolik, you can just sit down across from them at a dinner table and have a very casual, easy conversation with just about anybody at the station.”
Fulweber and the dozens of station staff often also help budding scientists learn the field skills not typically taught in coursework.
“Countless students and beyond have learned to change their first flat tire on the side of the Dalton Highway, mud splatter and all,” said Amanda Young, who manages Toolik’s Spatial and Environmental Data Center.
Two scientists change a flat tire on Alaska’s Dalton Highway while traveling to a research site north of Toolik Field Station in August 2018.
Being part of the ҹɫ, Toolik also offers familiar rules and structure that are sometimes missing from a remote field setting, Young said.
“It allows students to feel comfortable about pushing their limits while still having a safety net,” she said.
Trailing new pathways
Recently, Toolik has started taking a more active role in providing opportunities for students and early-career researchers, according to the station’s science director, Syndonia Bret-Harte.
The station’s Tundra Award, for example, provides students and early-career researchers with up to 10 days at Toolik to conduct an independent project. It’s fully funded by donations from the Toolik community. Since the inaugural cohort in 2022, the program has supported 16 awardees. Most had never been to Toolik before. Now, at least half of those awardees have continued or plan to continue research at the station.
“It’s been fantastic to see how just 10 field days can drive the overarching themes and questions for multiyear research proposals,” Bret-Harte said.
Fulweber, who now manages Toolik’s GIS team, in 2017 also helped launch a summer technician position for students or recently graduated undergraduates. His own experiences as a student motivated him.
“I can remember going out as a student and GPS-ing cracks in the sidewalk and mailboxes on the side of the campus road,” said Fulweber. “While that was great in terms of learning skills, it wasn’t the direction that I wanted to take my career.”
He and others wanted to bring students to the Arctic, an approach that has proven successful. All but one of the summer technicians have entered graduate programs or continued careers in GIS science.
Bret-Harte said the field experiences at Toolik resonate beyond their immediate impact on students.
“It’s not just about their early career. It’s also about the contribution they will have going forward,” she said. “These students are part of the next generation of Arctic scientists, who will ultimately be key in helping us adjust and respond to a changing Arctic.”
A research team heads up the driveway from Toolik Field Station. The truck is covered in mud from the 360-mile drive to the station on the mostly unpaved Dalton Highway.
Haley Dunleavy is the communications manager for Toolik Field Station.