The Lamont-Doherty Earth Observatory (LDEO) is a part of the Earth Institute at Columbia University where roughly 200 PhD researchers and 90 graduate students are involved in earth-science research. “Its scientists study the planet from its deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean, providing a rational basis for the difficult choices facing humanity.”
Miriam Cinquegrana, administrative coordinator at LDEO, has initiated a series of photo exhibits “to provide a space for members of the Lamont community to explore their passion for photography and to share their artistic work.” The hope is for these individuals to make connections and engage their research in new ways, noted Cinquegrana. Previous landscape exhibits have included Patagonia and Easter Island, as well as The Aleutians.
The newest exhibit, Antarctica, is the third display to feature photos taken by scientists as they perform their research in the field. Pieces from this exhibit are displayed here, and highlight photos taken by the following scientists: Isabel Cordero, Nick Frearson, Jonathan Kinslake, David Porter, Margie Turrin, Martin Wearing, Carson Witte, and Robin Bell.
“Each year Lamont scientists travel the globe with their research. This exhibition provides a small glimpse into the beauty and fragility that is Antarctica. These images were taken by Lamont Scientists as they went about their daily research studying topics as diverse as ice dynamics to tectonic origins and ranging from the Antarctic Peninsula to the Ross Ice Shelf and beyond into the East Antarctic interior.”
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.
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.
Visit Wyoming Public Media.org 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.
In the Eastern Cordillera of Bolivia, pollen grains travel from near and far to become sandwiched in layers of snow in the Andean mountaintops, ultimately becoming trapped as the layers turn to ice. Such is the case on the Illimani Glacier, which towers approximately 2,500 meters over Lake Titicaca. The lake sits at an altitude of 3,800 meters above sea level in what was the heart of the ancient Incan Empire.
University of Bern paleoecologist Sandra Brugger headed a team of researchers from various European universities to investigate the vegetative history of the Andean region. Their findings, published in Quaternary Scientific Reviews, indicate that the Inca used sustainable land use practices and that large scale ecological changes did not occur until 1740, long after the Spanish invasion and fall the Inca. The study is one of the first to reconstruct past ecology using pollen grains pulled from glacial ice.
The goal of Brugger’s study was to determine the resilience potential of the Andean mountain-forest ecosystem to a varying intensity of anthropogenic land-use practices. The researchers constructed a timeline of vegetation from 10,000 BC through to the present day. Of particular interest were the years following 1438, which represented the transition from the rise to the demise of the ancient Inca, which was then followed by the the reign of their Spanish conquerors. The degree to which the indigenous peoples altered their environment is a topic still deeply debated amongst researchers.
Much like tree rings, glacial ice accumulates in distinct annual layers; therefore, scientists can date ice core samples by ring counting, analyzing the layer’s isotopic signature, or by finding evidence of volcanic eruptions that have been well-dated throughout history. These methods are extremely accurate. Ice from the uppermost layers, which correspond to the last two-hundred years, can be dated within two to five years, while the ice corresponding to the time period of the Incas can be pinpointed to within two decades of accuracy.
The methods for extracting ice cores are actually quite challenging, Brugger said. An experienced team is required to extract samples from high altitudes because conditions become increasingly treacherous with elevation. Moreover, they must ensure that samples remain frozen throughout the delivery process—in this case, from Bolivia to Switzerland. “If they melt, samples are no good,” said Brugger.
The team of Margit Schwikowski at the Paul Scherrer Institute in Switzerland undertook these dangerous drillings, climbing to an elevation of approximately 6,000 meters above sea level. Additionally, they analyzed the chronology and measured many chemical species in the ice cores. Two core samples from the Illimani Glacier were extracted: one in 1999 and another in 2015.
Once in the lab, Brugger applied a series of evaporative and chemical-processing techniques to isolate pollen grains from samples corresponding to specific time periods. Each of the samples held approximately 500 pollen grains. “A good sample took me two to three hours to identify,” she said. A bad sample, she added, could take an entire day. The whole process took about three months.
The trickiest part, according to Brugger, was the patience required to identify the pollen. Not only is the catchment area of Illimani large, but the Amazon basin is also one of the most biodiverse regions on the planet, so many different species of pollen were represented in the samples. Undoubtedly, the identification process was painstaking work that required long days behind a microscope at a lab bench – far from the charm of the Bolivian Glacier.
Much of the previous research on Andean vegetation was constructed using pollen grains from lake sediments, noted Brugger, which ultimately captures more of a local signal from vegetation directly surrounding the lake. In what was the heart of the Incan Empire near Lake Titicaca, archaeological records suggest that pre-European cultures were highly advanced, domesticating llamas and alpacas, harvesting a wide variety of crops, and practicing metallurgy. Together, these practices could have brought about significant land-use impacts.
Digging deeper, researchers found that llama dung was an important maize fertilizer for the indigenous Andeans.
The switch to agricultural reliance allowed the Inca to abandon traditional hunting and gathering methods and supported the growth of society. An article recently published in the Journal of Archaeological Science details how oribatid mites that once dined on llama feces have been found in sediment cores from wetlands such as Lake Marcacocha, high in the Andes. As merchants passed through these areas with their llamas and maize yields, they boosted the oribatid mite population of the wetlands. This population boom strongly correlates with the time period dominated by the Inca (1483-1533), and the mites’ eventual decline corresponds to the arrival of the Spanish conquistadors, who wiped out the Inca and replaced their llamas with cows, horses, and sheep.
Interestingly, a study published in Applied Animal Behaviour Science suggests that llamas are not as impactful on the landscape as the Old World animals brought over by the Spanish. While llamas graze evenly among the various plant types, cows and sheep appear to be more scrupulous in their dietary decisions. Llamas do not eat plants down to their roots and have padded feet that are less environmentally destructive than hooves. Additionally, explained Brugger, while the native Puna grasses declined around 1740, the population of nutrient-loving weedy species escalated due most likely to the increase European cattle grazing activity. Therefore, the Incan llama grazed the land in a way that was sustainable to the Andean ecosystem, while their European counterparts decimated the land.
Unlike lakes, glaciers trap pollen on a larger scale, as particles drift in from a catchment area of approximately 200-300 kilometers in each direction. Brugger’s research suggests that, on a large scale, the Incan people did not change the Andean forest composition. It is important to note that local versus regional pollen collection methods do not necessarily contradict one another, said Brugger. Instead, they reveal that pockets of disturbance may have occurred closer to the lake where paths and roads were constructed, but overall, the Incan empire did not leave a significant ecological footprint.
The team identified vegetation that dates as far back as 10,000 BC, establishing an ecological baseline of plant diversity prior to human intervention in the landscape. The baseline served as the control for which human-induced vegetation change over time could be compared.
Brugger found small signs of maize, quinoa, and amaranth, after AD 1, suggesting that the Incas, as well as the indigenous populations before them, grew agricultural crops. Despite signs of human impact, Puna composition did not deviate from previous centuries.
Likewise, the expansion of Polylepis and Alnus after the year 800 followed a warming climate trend. Although Alnus, commonly know as alder, was favored for agroforestry, its range did not dissipate during the Incan regime. According to the book An Environmental History of Latin America, the Incan emperor himself maintained a sustained population of Alder and inflicted harsh punishments for unauthorized logging. In an area naturally defined by so little trees, the alder’s continued existence suggests strict environmental regulation. Its population soon declined with the arrival of Europeans.
According to Brugger’s data, changes in the mountain forest composition didn’t occur until around 1740 (two hundred years after the fall of the Incan Empire), implying a long transitional period before the Spanish were able to establish a stable land-use system. After 1740, the pollen record showed a rapid increase in dry grasses and nutrient-loving, weedy species, typical of pasturelands. Then, around 1950, signs of eucalyptus and pine appear in the pollen record, a result of the Bolivian land reform that promoted timber plantations.
Brugger is now stationed at the Desert Research Institute in Reno, Nevada, analyzing pollen and charcoal in ice cores from Central Greenland in order to reconstruct the response of sensitive Arctic ecosystems to past climate change. “It was a sensation that the approach actually worked,” said Brugger, “as the site was extremely remote from any plants — and pollen.” The prestudy to the project is published in The Holocene.
Glaciers provide an incredible glimpse into the past because they safeguard microscopic clues that allow researchers to uncover our most ancient secrets. For instance, Brugger’s study suggests that the Incan people, though large in number, were able to form a society that peacefully coexisted with its environment. Modern society has largely degraded the Bolivian ecosystem, but might learn a thing or two by studying ancient Incan methods of sustainable agriculture and agroforestry. Brugger’s research is part of a larger project that examines glacial cores from around the world to explain our past. As the project gains momentum, scientists can begin to unravel other fascinating mysteries trapped within glacial ice.