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Antarctica—the coldest, driest and most remote continent on Earth—is proof that life can thrive even in the most unlikely of places.

For humans, it’s hard to imagine a much harsher environment: Inland temperatures in Antarctica can drop below negative 76 degrees Fahrenheit in the winter, and a sheet of ice and snow more than a mile thick covers most (though not all) of the land.

Few plants and animals can survive in Antarctica’s McMurdo Dry Valleys, a frigid desert that is free of ice. But researchers from С���� Boulder have made trips to the area for more than 30 years to study the unique streams and organisms that inhabit the area in the summer months.

The water level in the region’s streams varies greatly year over year, so scientists are fascinated by how life has continued to thrive there at all. The organisms there must adapt to extreme conditions to survive—and they do.

Diane McKnight collects measurements from a stream during the Antarctic summer. (Credit: Diane McKnight)

Researchers pose for a photo near Lake Fryxell in Antarctica. (Credit: Mike Gooseff)

A helicopter perches on Canada Glacier while shepherding researchers to the McMurdo Dry Valleys. (Credit: Mike Gooseff)

“I've been struck by how robust these stream ecosystems are,” said Diane McKnight, a distinguished professor at С���� Boulder’s Institute of Arctic and Alpine Research (INSTAAR) and a founding principal investigator of the (LTER) Program.

“The idea of these stream ecosystems just waiting for water—that sounds like they're just at the edge of existence. But we've learned that isn't really true.”

McKnight, who has spent 27 seasons in Antarctica, reflected her years of Antarctic research at a campus event on Thursday, Feb. 5. She explained how environmental changes can easily upset the delicate ecological balance in the dry valleys. Still, the region has a lot to teach us, not only about the environment in Colorado and other parts of the world, but also about personal resilience in the face of adversity.

The talk was part of a series of events commemorating INSTAAR’s 75th anniversary.

Life in the McMurdo Dry Valleys

Despite the challenges of living in Antarctica, cold-water fish, seals, whales and penguins thrive in the freezing waters off the coast. Plankton, krill and algae provide vital food sources.

Inland, the landscape becomes more desolate. But even in the McMurdo Dry Valleys, streams still flow during the short Antarctic summer and are home to a diverse ecosystem of algae and microorganisms.

“You see it in stream beds. You see these carpets of algae. We see it under the lake ice or at the bottoms of the lakes,” said Mike Gooseff, a professor in the Department of Civil, Environmental and Architectural Engineering at С���� Boulder and a fellow at INSTAAR.

Gooseff is also the current principal investigator of the Dry Valleys LTER, a decades-long research project that studies life in the region.

“A lot of that life is hiding in plain sight. If you walk through this environment, or you fly over it, you don't see it. It doesn't jump out at you as life. But there is this whole really interesting—and in some cases, sensitive—ecosystem,” he said.

McKnight said that some of the most interesting inhabitants of the region are diatoms—single-celled algae that are surrounded by glassy cell walls. Like plants, they can perform photosynthesis, converting sunlight to energy and carbon dioxide into oxygen. Diatoms collectively produce 20% to 50% of Earth’s atmospheric oxygen.

Research by McKnight, Gooseff and others has uncovered key features of the streams that allow life to thrive in the dry valleys. Algae growing on rocks underwater, for example, take up nutrients like nitrogen and phosphorus. Eventually, they release those nutrients, which settle into the sediment at the bottom of the streams. In a full-circle moment, the nutrients later filter back into the water from the sediment.��

“This is not just happening in the dry valleys,” McKnight said. “It’s probably happening in lots of places where there are slimy rocks and algae growing on the rocks. We think this kind of cycle is happening in other desert streams, and these sediments underneath the streams are like repositories or reservoirs for nutrients when there is water and the algae can grow.”

But conditions in the environment can affect how well this cycle works. Gooseff remembers that in 2002, a particular bad flood season caused water levels in one lake to rise by about 40 inches. The extra water stirred up so much sediment in the lake that the phytoplankton couldn’t get enough light for photosynthesis.��

These kinds of disturbances can have big impacts on the environment, not just in the Dry Valleys but in other aquatic environments around the world, too.

What’s ahead?

Both McKnight and Gooseff hope the LTER will continue long into the future. The Dry Valleys are a unique ecosystem where scientists can study specific processes, like those cycles of nutrients, without animals and plants affecting their results.��

A long-term study like the LTER gives the researchers better perspective on what is and isn’t normal for the area and how the ecosystem responds to different conditions over time, Gooseff said. A shorter-term project might not capture some of the changes that happen from year to year.

But Antarctica itself offers a lot of lessons in resilience.

“We call Antarctica a ‘harsh environment,’” Gooseff said. “But there is a recognition that these ecosystems thrive.”

McKnight said Antarctica has taught her to be more resilient and overcome unexpected situations and challenges. She has also gotten special joy from bringing students there over the years.��

“As the lead scientists, we never get jaded, because we have all this awe and wonder. But it is also rewarding to be with the graduate students who go down there, and then see how being in this challenging environment prepares them to test themselves—they think they can do anything.”