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The McMurdo Dry Valleys don’t look like they belong in Antarctica. Largely devoid of snow, the landscape is mostly dirt and rock. When explorer Robert Falcon Scott trekked the area in 1903, he referred to it as “the valley of the dead.”

But that name is a misnomer. While life may not be evident to the naked eye, beneath the icy surface of Lake Fryxell, microscopic communities teem with life. Microbes, nematode worms and tardigrades thrive in this environment.

“I think that it’s unfortunate that [Scott] did not bring his scuba gear or his microscopes because actually there is a lot of life here,” said Abbey Dias, an assistant diving and boating safety officer for the �����о��� Coastal and Marine Sciences Institute and the Bodega Marine Laboratory.

Dias and a group of �����о��� researchers spoke on Jan. 24 via a YouTube livestream from Antarctica’s McMurdo Station. In a seminar titled “�����о��� in Antarctica,” the team shared their experiences after completing a four-week field season at Lake Fryxell. Topics ran the gamut, from strategies for existing in 24/7 daylight and living off frozen/dry foods to insights on traveling to the Antarctic, the team’s research questions and performing safe science in a harsh environment. The livestream was hosted by the YouTube channel Exploring by the Seat of Your Pants.   

“Our goal out here for our research at Lake Fryxell [is] to understand how the microbial life persists in the harsh environment and how it responds to change,” Dias said.

Lake Fryxell is like a time capsule. It provides scientists with a window to investigate an ancient period of Earth’s past, when photosynthesis was just making waves on the biological scene and oxygen was becoming a critical component of the atmosphere.     

“Lake Fryxell is really unique because it’s undisturbed unlike any other bodies of water that I’ve ever dove in in my life,” added Dias, noting that there are no predators, like fish or sharks, in Lake Fryxell’s waters. “It’s really delicate and fragile.”

Chipping away at the ice

To access the depths of Lake Fryxell, the team spent around 28 hours creating a diving hole, chipping through nearly 12 feet of ice. On diving days, they would break through areas that refroze, the hole being their portal to Lake Fryxell’s hidden microbial world.

As Dias swam through the murky waters, she encountered microbial mats — communities of bacteria and microalgae that form primitive structures. The structures, which both cover the lake floor and are buoyed in the water by gases produced by photosynthesis, can look like carpets, layers of lasagna, arches and honeycombs, among other shapes and forms. She relayed what she saw to the scientists on the surface, using creative descriptions like “slimy fingers on a rock,” and took samples for later analysis.

“I’m really interested in Antarctic Lake ecosystems because they’re mostly microscopic, so it’s a little bit like going back into Precambrian time,” said Dawn Sumner, a professor in the Department of Earth and Planetary Sciences and the team’s leader.

Sumner’s objective during this past field season was to install experimental systems that will help her and her colleagues monitor changes in Lake Fryxell’s oxygen levels during the winter season. Her goal is to better understand how the oxygen in the lake’s ecosystem shifts when sunlight is limited.

“That’s related to trying to understand how we accumulated oxygen on Earth about 2.5 billion years ago,” Sumner said.

Big things, small beginnings

During the YouTube livestream, other members of the research team also discussed their projects.

�����о��� alum Tyler Mackey, an assistant professor at University of New Mexico, took core samples from the region to learn about past climate conditions and installed shade structures over some of the microbial mats to learn about how blocking sunlight affects the ambient environment. �����о��� alum Marisol Juarez Rivera, a postdoctoral researcher at the University of New Mexico, investigated the role of oxygen in shaping microbial mats; and Elisa Merz, a �����о��� scientific diver and postdoctoral researcher at the University of Constance in Germany, analyzed how diatoms — single-celled algae — survive in the dark, sulfidic environment of Lake Fryxell.     

For Dias, the trip emphasized that “science really takes teamwork.”

“I’m just really proud to be working with this team and all the unique skill sets and personalities that make our team stronger,” Dias said.