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by Jennifer Donovan
It didn't take Kevin Endsley—who hails from Houston—long to learn that Alaska's Bering Glacier is nothing like Texas. It's nothing like Wisconsin either, Silvia Espino, a classmate from Milwaukee, soon discovered.
The glacier was a vast natural laboratory for Endsley and Espino, both juniors in applied geophysics. There they joined senior Joshua Richardson and Michigan Tech faculty members John Gierke and Nancy Auer on a ten-day research expedition in August 2007.
At the Bering Glacier camp on the edge of Vitus Lake, near the south-central coast of Alaska, the campus contingent worked alongside Robert Shuchman, codirector of the Michigan Tech Research Institute, who has been conducting research there with his team since 2000. The MTRI scientists designed a sensor that enables the US Bureau of Land Management to accurately measure and analyze the melting of the gigantic glacier.
The students were fresh from a summer course in field geophysics, where they learned techniques such as recording and interpretation of electrical, magnetic, and seismic data. But it hardly prepared them for the glacier, where they camped in tents and canvas Quonset huts and had to hop a boat or a helicopter from the remote base camp to eighteen even-more-remote sites on and near the ice. There Richardson positioned insulated seismometers to record data that they hope will tell them when and where the glacier is breaking bedrock as it moves and "calves" or shatters, while Endsley and Espino surveyed the resistivity or potential of water to resist an electrical charge at varying depths and locations.
A Salty Freshwater Lake
Endsley and Espino measured the resistivity in and around Vitus Lake and the nearby Gulf of Alaska. Their goal was to map the freshwater-saltwater interface as a first step towards determining how freshwater and seawater were exchanging between the lake and gulf. They hope to use the data they collected to explain why the large, deep glacial lake is saline below 150 feet.
They measured saltwater as shallow as 10 feet near the Gulf. The freshwater table ranged from 50 to 60 feet deep in most of the inland areas. The research students also learned that there is not a clean line of demarcation between freshwater and saltwater. Instead, the water is mixed and brackish at the interface.
Although seawater may be periodically flowing inland during the high tides and reduced glacial melting of winter, that water never reaches Vitus Lake. So the students offer an alternative hypothesis to explain the presence of saltwater in the inland lake: since the entire area was part of the Gulf of Alaska before the retreating glacier sealed off Vitus Lake (by depositing sediment between the lake and the coast), salt from the seawater that used to cover the land may have been deposited in the sediment. As a result, when freshwater flows underground toward the Gulf, it may be leaching the salt out of the sediment.
Stranded by a Storm
Each student had an opportunity to lead the team on a mission to deploy and collect the seismometers or to perform a resistivity survey. During one of Espino's missions, the weather turned ugly and the city girl and her team found themselves stranded seven miles from camp.
"The ominous clouds along the horizon told us immediately that our hope of getting a helicopter ride back to camp wasn't going to happen," she recalls. "We left the equipment and started walking, even though our feet and ankles were still sore from an eight-hour hike a few days earlier."
When rescue appeared in the form of an ATV with a wagon attached, the Michigan Tech team clambered gratefully into the wagon. But their relief was short-lived. As the ATV made its way over a small hill, the wagon came unhitched and dumped the students out.
"When we finally realized that the driver and John [Gierke], who was riding beside him on the ATV, hadn't noticed that we weren't with them any more, we got out of the wagon and tipped it upright," Espino recollects. "They finally came back for us, and we all had a good laugh."
"Our students toughened right up," Gierke, an associate professor of geological and environmental engineering, says with admiration. "Their stamina was amazing. When they got back to camp after a full day in the field, they would rather download their data than eat dinner."
The students and Gierke presented their Bering Glacier research at MTRI's annual research poster session at Michigan Tech in October.
What About the Biology?
Nancy Auer's interest in the Bering Glacier research was sparked by MTRI's previous poster session, in 2006. As an associate professor of biological sciences, her question was: "Is anybody looking at the biology in Vitus Lake?"
The answer was no, so Auer joined the rocks and water researchers, to take a look at the life in Vitus Lake. She collected ten benthos, which are organisms that live on the bottom of bodies of water, and eleven plankton samples from the lake, using nets and dredges. She also collected specimens of fish, clams, and amphipods or small shrimp-like crustaceans that she later identified in the laboratory.
Inventive as field scientists must be, Auer sampled an algal bloom using a folded coffee filter. She also brought home some "snow worms" from the top of the glacier. Auer plans to return next summer and take a biological sciences student with her to study the benthos.
"I'd like to compare and contrast Vitus Lake with Lake Superior," Auer says. "Both are big and cold, and studying the Alaskan lake could teach us about the evolution of a large, freshwater lake like Lake Superior."
Auer and Gierke both call the Bering Glacier research experience invaluable for undergraduates. "Doing research in a field setting gives these students so much self-confidence," Gierke said. "They have firsthand knowledge of how field research is done. They will be prepared to tackle jobs involving fieldwork."
And they'll always remember their glacial adventure.