Nav: Home

Antarctic meltwater streams shed light on longstanding hydrological mystery

February 01, 2019

In one of the coldest, driest places on Earth, CU Boulder scientists have developed a possible answer to a longstanding mystery about the chemistry of streamflow, which may have broad implications for watersheds and water quality around the world.

The new study conducted in Antarctica's arid McMurdo Dry Valleys (MDV) region examined the nearly ubiquitous phenomenon that streams in all climates, regardless of their flow rate, tend to maintain a remarkably consistent concentration of dissolved minerals as they move through the landscape. In other words, moving water retains its chemical makeup regardless of whether it's going fast or slow.

Antarctica's dry, pristine conditions offer a streamlined--if far-flung--natural laboratory to test out why that's the case.

"The MDV region provides ideal hydrological study conditions," said Adam Wlostowski, lead author of the study and a postdoctoral researcher in CU Boulder's Institute for Arctic and Alpine Research (INSTAAR). "Here, we only have one source of water--glacial melt--and no deep groundwater, with permafrost acting as a physical barrier for the stream. By limiting the number of variables, we can learn a great deal."

The research, detailed in the journal Geophysical Research Letters, examined seven different streams in the Taylor Valley, where meltwater flows to ice-covered lake basins in just hours or weeks, compared to months or years in the Rocky Mountain region. As such, Antarctic streams have precious little opportunity to stagnate in the landscape.

"We expected the water at the stream outlets to look like the water at the head of glacier due to limited interactions with minerals," Wlostowski said. "And we thought that as the flow went up, the concentration would decrease. That did not turn out to be true. There was little to no variation even with flow change."

The results suggest that high levels of chemical weathering--the process by which solid minerals dissolve, much like rock salt in a puddle of warm water--are the primary mechanism for this streamflow phenomenon.

"These Antarctic polar desert streams host some of the most rapid chemical weathering rates in the world because their beds are made up of fresh sediments that see water for only 6-10 weeks per year," said Michael Gooseff, a professor in CU Boulder's Department of Civil, Environmental and Architectural Engineering. "This is another important lesson we have learned about this ecosystem that is transferrable to other parts of the world."

The study underscores the value of long-term data collection, Wlostowski said, which makes the study of hydrological phenomena possible. In this case, he and his colleagues drew on more than 20 years of streamflow observations collected by the National Science Foundation's McMurdo Dry Valleys Long?Term Ecological Research (LTER) Project, which has funded and supported CU Boulder students and faculty for over two decades.

The new study contributes to a high-level understanding of how streams behave geochemically and highlights the importance of stream corridors in shaping water quality before it reaches its end point.

"As climate and land use practices change throughout the world, we want to be able to predict how the quality and quantity of river water may change in response," said Wlostowski. "We can apply lessons from these relatively simplified hydrologic systems in Antarctica to temperate watersheds, where the human implications of environmental management may be much higher."
Additional co-authors of the study include Diane McKnight of CU Boulder and William Lyons of Ohio State University. The National Science Foundation and the Polar Geospatial Center provided funding for the research.

University of Colorado at Boulder

Related Water Quality Articles:

Revolutionizing water quality monitoring for our rivers and reef
New, lower-cost help may soon be on the way to help manage one of the biggest threats facing the Great Barrier Reef.
Trees for water quality credits
In a new study, UC Santa Barbara Bren School professor Arturo Keller links reforestation to water quality credits.
Improvements in water quality could reduce ecological impact of climate change on rivers
Improvements in water quality could reduce the ecological impact of climate change on rivers, finds a new study by Cardiff University's Water Research Institute and the University of Vermont.
Changes in rainfall and temperatures have already impacted water quality
Changes in temperature and precipitation have already impacted the amount of nitrogen introduced into US waterways.
Can we address climate change without sacrificing water quality?
Strategies for limiting climate change must take into account their potential impact on water quality through nutrient overload, according to a new study from Carnegie's Eva Sinha and Anna Michalak published by Nature Communications.
More Water Quality News and Water Quality Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...