Hunting for extreme microbes

This summer, Memphis Hill, Ph.D., a postdoctoral researcher in the laboratory of Brandon Briggs, Ph.D., professor of biological sciences, was awarded a postdoctoral fellowship through the Arctic Leadership Initiative. In late June, she led a team of researchers to collect water, ice and sediment samples from locations around Kachemak Bay.

"An objective for the Arctic Leadership Initiative fellowships is to elevate the UA System and Alaskans to be leaders in Arctic research," said Hill. "So being the people who go out and collect data and publish research about Arctic systems is within that mission statement."

Hill joined Briggs' lab in October 2023 and had the opportunity to lead the lab's annual summer fieldwork.

"Each year I take out a group [...] of undergrads, grad students and postdocs," Briggs said. "I think it was great this last year that Memphis was able to take the lead on this."

Hill led the group as they drove from Anchorage, took a water taxi across Kachemak Bay to a yurt, and then hiked five miles to collect samples at Grewingk Lake, Grewingk Creek and Humpy Creek.

"I had been down to Grewingk before," Hill said. "So I kind of knew how to get there, figured it would be a good spot and we hadn't sampled it yet."

The team collected samples in hopes of identifying microbes living in the sediment and water, including potential 'extreme microbes' - microbes that can survive in extreme environments, like underneath glaciers.

"There's other research labs at UAA that have been studying this watershed for a while but they don't look at microbes," Hill explained. "So we were hoping to add some more data to their robust data set."

Hill hopes to compare which kinds of microbes are found in Humpy Creek with Grewingk Creek and Grewingk Lake.

"I definitely expect to see different microbial communities in the different creeks because the source waters are so different," she said. "The glacial lake and Grewingk Creek are fed from glacial melt versus Humpy Creek is more of a surface runoff from snow melt and precipitation, so you end up having very different chemical make ups in the water."

After being collected in the field, the samples were transported back to Briggs' lab at the Anchorage campus for analysis with DNA sequencing technology.

"We extract the DNA from the cells and then we sequence the DNA," said Hill. "It gives us the base pairs that are present, and then we use bioinformatics to actually identify what those sequences are."

Identifying which species of extreme microbes are living under and within Alaska's glaciers has some out-of-this-world implications. According to Briggs, this research may provide ideas on how microbes could survive on icy planets or moons in the solar system.

"The type of environments that we're seeing underneath these glaciers [are] analogs for Europa, Enceladus - maybe even the polar caps of Mars," Briggs said. "If we're going to find life on Mars, that's probably where they're at - underneath the glaciers."

Hill sees important down-to-Earth value in the research.

"I'd say the number one thing is knowing who's here, microbe-wise, as these glaciers continue to melt, and these ecosystems continue to change with warming," Hill said, "Grewingk Glacier has been melting. Not at as fast a rate as some other glaciers in Alaska, but most of them are losing mass."

While the samples the team collected have not yet been fully analyzed in the lab, according to Hill "the sequencing is supposed to happen imminently." While Hill is interested in revisiting Grewnigk at some point in the future to collect more samples, the team has plenty of work in the lab ahead.

"We have a lot of work to do just with the samples we collected this year," Hill said

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