Around the world, researchers seek to understand just how fast glaciers are melting as the planet’s climate warms. In Grand Teton National Park, two new studies are underway as researchers investigate glaciers from different, but complementary perspectives. The first is a study by National Park Service (NPS) scientists who have begun tracing the melt and movement of five glaciers in the park. The second study reflects upon research by a Washington State University biologist, who, in turn, is analyzing how these melting glaciers will affect downstream biodiversity.
Study 1: Tracking Glacial Melt
The crests and canyons of the Teton Range in the Rocky Mountains were shaped during the Ice Ace of the Pleistocene era 2,580,000 to 11,700 years ago, when the earth experienced its latest period of repeated glaciations. These giant glaciers retreated 10,000 years ago, and the smaller glaciers we see today are the result of the Little Ice Age that lasted from about AD 1400 to 1850.
Glaciers tend to be highly responsive to climate change because they react both to temperature and precipitation. In 2014, NPS scientists and climbing rangers began measuring the health of several glaciers in Grand Teton National Park. They include Peterson, Schoolroom, Teton, Falling Ice, and the revered Middle Teton Glacier. Located on the eastern slope of the third highest peak in the Teton Range, Middle Teton is one of the first sights noticeable from the highway, and is a popular mountaineering route for visitors.
Each year, scientists busy themselves planting PVC stakes in the ice, setting up time lapse cameras, and using GPS systems to quantify ice surface change. This year, from June through September, approximately 25 feet of the snowpack melted on Middle Teton. While this certainly sounds like a large loss, it is still unclear whether this level of melting is normal given the sparse collection of historical data. Because this study has just begun, it will take about ten years before park scientists can really see how their data fits in with climate change models.
While there has been some intermittent monitoring over the past few decades, little prior research has been done to track the rate of glacial melt in the park. Mauri Pelto, professor of environmental science at Nichols College and director of the North Cascades Glacier Climate Project, says this is probably because the Teton glaciers are not very large in comparison to other glaciers in the region, and thus are not as far-reaching in terms of their water contribution to the overall watershed. In contrast, said Pelto, glaciers in Montana’s Glacier National Park are much bigger and thus affect the surrounding ecosystems on a much larger scale, so more information has been collected regarding their melt rate.
Check out: From a Glacier’s PerspectiveA blog by Mauri Pelto
Study 2: The effect of surface glaciers on downstream biodiversity
Nevertheless, the glaciers of the Grand Tetons do have a direct impact on their local environment, especially on the ecosystems located downstream. “I am very interested in the Grand Teton glacier study as it directly informs my research,” said Scott Hotaling in an interview with GlacierHub. Hotaling is a postdoctoral biological researcher at Washington State University analyzing biodiversity in high elevation alpine streams.
Hotaling and his crew have trekked up the steep alpine slopes every year since 2015, sometimes in very bad weather, to collect diversity samples in various types of alpine streams. They examine streams fed by groundwater aquifers, permanent surface glaciers, snowfields, and subterranean ice (also called “icy seeps”). In the field, stream type can be identified by a variety of characteristics such as temperature and the specific conductivity of water, explained Hotaling.
For instance, glacier fed streams are very cold and display a rugged stream channel while groundwater streams are warmer, at 3-4 degrees Celsius. Icy seeps have lobes like a glacier so they look like a flowing mass of rock and come out at about 0.2 degrees Celsius. Moreover, streams that interact with rock have a much higher ionic content than snowmelt or glacier fed streams.
Most of Hotaling’s work focuses on high-elevation stream macroinvertebrates like stoneflies. However, in order “to fully understand the breadth of climate change threats, a more thorough accounting of microbial diversity is needed.” Therefore, his recently published study in Global Change Biology focused on the diversity of microbial communities in high elevation alpine streams in both Grand Teton National Park and Glacier National Park.
He found that the microbial biodiversity of alpine streams does not differ between these two subranges of the Rockies, but does indeed differ depending on the origin of its water source. Streams fed by the parks’ iconic surface glaciers support microbes that are not found in other alpine stream types, and thus increase environmental heterogeneity. Importantly, results from Hotaling’s research show that patterns of microbial diversity correlate strongly with overall trends in biodiversity.
Should the park’s glaciers disappear, alpine stream water will warm, causing them to become more biodiverse because more organisms thrive in warmer streams than extremely cold ones. However, this diversity will instead represent warm-adapted species. Consequently, the glacier-fed streams will become more similar to the landscape, and biodiversity will therefore become more homogenous.
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to learn more about Hotaling’s research on Lednia tetonica, a macroinvertebrate that can only be found in alpine streams of the Grand Teton Mountain Range
Lednia tetonica nymph found in Grand Teton alpine stream (Source: Wyoming Public Media/Cooper McKim)
Interestingly, while snowmelt-fed streams and glacier-fed streams each have their own unique biotic communities, icy seeps boast representative species from both communities. Because icy seeps are shaded from solar radiation by insulating debris cover, researchers are hopeful that some of the rare glacial species will persist even after the surface glaciers are gone. We do not know how long the subterranean rock glaciers will last, but “we do know that the Beartooth Mountains support subterranean ice blocks that have been there for a long time in places where there aren’t glaciers around them,” noted Hotaling.
Just like the NPS glacial melt study, Hotaling’s study is in its infancy. There is a lot of “noise” collecting environmental data in such high locations, and so far, his team has only collected five years-worth of data. “We are aiming for the ten-year mark,” said Hotaling, in order to determine if there is a trend in overall biodiversity over time as the glaciers of Grand Teton and Glacier National Park diminish due to a perpetually warming climate.
It is hard to say just how long the Tetons’ glaciers will last. While some research shows that Glacier National Park could be glacier-free within the next few decades, there is also contradicting research that suggest some glaciers are shrinking more slowly than others. Whether this is due to high altitudes, persistent shading by the mountain slopes they have retreated into, heavy avalanching, or a persistent snow accumulation zone, it seems some glaciers may hang in there a bit longer, noted Pelto. Still, the overall trend is negative.
“I monitor glaciers in mountain ranges around the world – two-hundred and fifty of them – and they’re all doing the same thing. They’re all showing the same climate signal” said Pelto. “They [the Tetons] are not unique. We are fooling ourselves if we think they are doing something differently.”
Sarah Strauss, who lived in Wyoming for over twenty years, expressed: “I can say that people in Wyoming are very proud of the National Parks in the state, both Yellowstone and Grand Teton, and also identify strongly with being part of a mountain culture. Glaciers, as part of that mountain culture context, are an essential feature of the landscape.” Losing them will surely impact both the natural and cultural dynamic of the region.
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