Research

Deploy, recover, sample, deploy... A day in the life of a CTD Watchstander (GO-BGC)

David J Lubinski — Fri, 04 Apr 2025 17:48:30 +0000

Deploy, recover, sample, deploy... A day in the life of a CTD Watchstander (GO-BGC) David J Lubinski Fri, 04/04/2025 - 11:48

Grad student Genevieve Clow is currently working aboard a research vessel on a 41 day expedition to the Indian Ocean. Read her blog post about gathering hydrographic measurements and collecting water samples.

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Desert reservoirs capture and store organic carbon, according to new research

Gabe Allen — Thu, 03 Apr 2025 19:00:00 +0000

Desert reservoirs capture and store organic carbon, according to new research Gabe Allen Thu, 04/03/2025 - 13:00

Gabe Allen

A new investigation from Abby Eckland, Irina Overeem and collaborators reveals a surprising climate benefit of damming in the desert.

In 2021, while revelers across America celebrated the fourth of July, three researchers waded through a shallow river delta in the New Mexican desert. Abby Eckland, Irina Overeem and Brandee Carlson stood in what remained of the Rio Grande—years of drought had shrunk the river to a few small channels. Just downstream, the channels entered the Elephant Butte Reservoir—New Mexico’s largest.

Then, all of the sudden, the water started rising. First, to the scientists' calves. Then above their knees.

“Wow, it’s really coming up,” Overeem remarked.

The river became muddy and turbid. Debris—tamarisk leaves, pine needles and trash—floated down the widening channel. Dead fish rose to the surface and came to rest in the weeds on the riverbank. It was a flash flood.

At this point, a normal sightseer would probably head for the hills, but the scientists, instead, responded with excitement. This was an opportunity for inquiry into an ephemeral natural phenomenon. Eckland bottled up water samples while Overeem and Carlson checked on the sensing equipment they had placed in the river that morning.

A carbon sink in the desert

Abby Eckland (left) and Irina Overeem back at the motel after a muddy day of field work on July 5, 2021. Photo by Brandee Carlson.

This month, the team published a new study, led by Eckland, in Water Resources Research. The analysis draws on their 2021 field season and parses information about sediment and organic carbon in river water for a surprising result. Reservoirs like Elephant Butte may sequester organic carbon within layers of sediment, especially during periods of drought and flash floods. Essentially, the reservoir acts as a carbon sink—trapping organic material that would otherwise emit carbon dioxide through natural decay.

A sonar system mounted to the front of Eckland’s packraft measures underwater river geometry on the Rio Grande near Elephant Butte Reservoir. Photo by Abby Eckland.

The explanation lies in physics. Normally, when water flows into a reservoir, it spreads out over the surface. But, if the river picks up enough sediment, the process flips upside down. Instead of the river water fanning out on top, an underwater current plunges it downward. Scientists call this a “hyperpycnal plume.”

“We saw this plume developing based on the data from instruments we casted near the mouth of the Rio Grande,” Eckland said. “That means that it’s likely that whatever sediment, carbon and other materials are being carried will flow to the bottom of the reservoir and get deposited.”

Armed with this evidence, the researchers next turned their attention to the samples they had gathered in the field. It was time to, literally, dig through the muck.

Droughts and floods

In the laboratory, an array of tests characterized the contents of samples from the river water, reservoir water, and underlying delta and reservoir beds. Once they had these values mapped out, the researchers compared their results to a repository of historical data from the U.S. Bureau of Reclamation—a process aided by Eckland’s familiarity with the system after years of interning with the Bureau. This allowed them to extrapolate their findings back in time.

“Abby had a lot of connections to the scientists there and knew what to look for,” Overeem said. “It was really good that we had this, sort of, liaison to the federal government system. It led to a unique partnership.”

Finally, the team had all of the information they needed to compare carbon sequestration in the river delta and reservoir over seasons, years and even decades.

This second set of analysis provided the study's most striking result. Not only was organic carbon getting buried beneath layers of sediment, but this process was actually amplified during drought. Because the overall footprint of the reservoir was smaller during these periods, sediment piled on faster.

“There’s less of a footprint when the water level is low,”Eckland said. “There’s just less space for it to go, so you get more carbon buried per area.”

The serendipitous timing of their field excursion produced another insight—carbon burial rates are also elevated during flash floods. It makes sense, of course. Flash floods tear through the landscape picking up loose soil, leaves and whatever else is lying around. By the time they reach the reservoir, they are full of sediment, which creates a hyperpycnal plume, and full of organic material, which is subsequently buried.

Though carbon burial in reservoir sediment has been observed in the past, the new paper is the first to identify exactly how it happens.

“The key link is the role of the hyperpycnal plume in delivering carbon to the bottom of the reservoir,” Eckland said.

Next steps

As with any novel scientific finding, the next step is to confirm the discovery and gather more information. This is already underway. Overeem recently returned to the site with former INSTAAR postdoc and current University of New Mexico assistant professor Marisa Repasch to gather samples from the reservoir bed. Repasch is an expert in organic carbon storage in the landscape, and her lab is hard at work digging deeper into the chemical characteristics of the sediment. So far, the preliminary results are promising.

“We found even higher numbers than what Abby estimated,” Overeem said.

The researchers are hopeful that these results might help water managers make more informed decisions in the future. Essentially, they have highlighted a unique benefit of dryland reservoirs—that they might capture and store the source material of Earth’s most ubiquitous greenhouse gas. This insight could become important in weighing potential costs and benefits of infrastructure on the landscape.

“There is renewed interest in carbon sequestration, especially because there might be a market for stored carbon at some point in the future,” Overeem said. “It’s a futuristic vision, but we will need this kind of information to get there.”

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact INSTAAR Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

Abby Eckland, Irina Overeem and collaborators investigate how a reservoir on the Rio Grande buries organic carbon beneath layers of sediment. The researchers found that the process is amplified during drought and flash floods.

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The Elephant Butte Dam in 2022. Photo by Abby Eckland.

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The Elephant Butte Dam in 2022. Photo by Abby Eckland.

This monstrous mama laid the world’s largest egg (National Geographic)

David J Lubinski — Wed, 02 Apr 2025 21:55:03 +0000

This monstrous mama laid the world’s largest egg (National Geographic) David J Lubinski Wed, 04/02/2025 - 15:55

Gifford Miller has studied the fossilized eggshells of the elephant bird Aepyornis maximus and comments on how human predation may have contributed to their extinction.

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Drone experiment reveals how Greenland ice sheet is changing (91�� Today)

Gabe Allen — Thu, 27 Mar 2025 20:38:25 +0000

Drone experiment reveals how Greenland ice sheet is changing (91�� Today) Gabe Allen Thu, 03/27/2025 - 14:38

An INSTAAR-led study measured water vapor in Greenland’s air, collecting data crucial for improving climate models and forecasting Arctic changes.

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Thawing the mysteries of ancient climate changes

Gabe Allen — Wed, 26 Mar 2025 19:00:00 +0000

Thawing the mysteries of ancient climate changes Gabe Allen Wed, 03/26/2025 - 13:00

Gabe Allen

A new study from Chloe Brashear, Tyler Jones and others suggests abrupt warming events were preceded by periods of unusually stable temperatures during the last ice age. The researchers point toward shifting sea ice as a potential driver of the phenomenon.

On July 21, 2019, Chloe Brashear carried another disc of ice through the underground ice cave at the East Greenland Ice-Core project. The cave lay a few meters below the surface of the sprawling Greenland ice sheet, more than 200 miles inland from the coast. Brashear loaded the disc onto a hot aluminum plate and then stepped into the sampling room, where the melt water was pumped through an array of equipment that would filter it, vaporize it and produce a readout of its chemical contents.

Despite the sub-freezing temperatures in the cave, space heaters and an array of whirring instruments kept the sampling room hot. Brashear cast off her parka and got to work.

In most ways, it was a typical day of late-summer field work, but this day was also special. Brashear and her colleagues were analyzing samples extracted from deep within the ice sheet—more than 2,000 meters below the surface. The scientists estimated that the ice was more than 40,000 years old. Later that night, they would celebrate over drinks and grub.

Chloe Brashear poses in the drill trench at the East Greenland Ice-Core Project. Photo courtesy of Chloe Brashear.

New Insights

Five years later, Brashear—now a PhD candidate at Utrecht University in the Netherlands—has teamed up with her former mentor, INSTAAR fellow Tyler Jones, and others to publish new insights from their 2019 expedition. Their new study takes a fresh look at some of the most dramatic climate upheavals in Earth’s history: abrupt warming events that punctuated the last ice age, between 11,000 and 50,000 years ago.

The data revealed something unexpected. On average, the colder periods between warming events displayed variable temperatures—it might be very cold one decade and much warmer the next. But, during the few hundred years before an abrupt warming event, this volatility flattened out. Each rapid warm-up was preceded by centuries of unusually stable temperatures.

“Variability would start to decrease first at decadal and multi-year scales,” Jones said. “Then, a few hundred years later, on average, there would be an abrupt warming event.”

It was as if the climate system was holding its breath before suddenly exhaling in a burst of warmth. But why?

The new paper proposes that shifting sea ice conditions in the North Atlantic may be the missing puzzle piece. If their hypothesis is correct, it could reshape our understanding of Earth's climate system—especially in times of abrupt change.

Ice age heat

If the phrase "abrupt warming event" makes you think of modern climate change, you're not wrong. But, the events that Brashear and Jones focused on in their latest paper, known as Dansgaard–Oeschger events, were actually much more intense. Researchers estimate that, in the most extreme version of their projections, temperatures in Greenland may have risen by as much as 29 degrees Fahrenheit in less than a decade.

“As an analogy, imagine you live in Northern Maine when you start college, and by the time you finish college it feels like you’re living in Southern Arizona,” Jones said.

Climatic variability—basically the volatility of temperature fluctuations—has already been a focus of researchers hoping to understand the last glacial period. But, previous research lacked the precision needed to parse out the timing between changes in variability and these extreme warming events.

Freshly-drilled ice cores are stored in the ice cave, where they await processing and analysis. Photo courtesy of Tyler Jones.

That changed when Jones and his colleagues, including INSTAAR faculty Bruce Vaughn, Valerie Morris and James White, developed a new methodology for analyzing ice cores: continuous flow analysis. Instead of chopping an ice core into chunks and analyzing each separately, continuous flow analysis melts the core tip to tail, extracting a near-unbroken record of past temperatures. This allows scientists to study changes in climate on a millimeter-by-millimeter scale. In the case of this project, continuous flow analysis allowed Brashear to interpret temperature data for distinct intervals of 7 to 15 years of ancient history.

“If you continuously sample the ice core, you capture all this detail that you are losing with discrete sampling,” she said.

This technique provided the new paper’s biggest insight: the stable temperatures that preceded each of the Dansgaard–Oeschger events. It also provided Brashear with a powerful dataset to compare to sea ice models.

The comparison once again produced an intriguing result. The changes in temperature variability were highly correlated with modeled changes in sea ice variability. In the new paper, Brashear provides a hypothesis: the leading edge of North Atlantic sea ice may have become more stable, which would have decreased its influence on short-term temperature fluctuations in Greenland.

If true, the finding could influence scientists seeking to refine models of Earth’s climate and gain insights into the modern era.

“This result doesn’t directly apply to the modern changes we’re seeing, because they are unprecedented,” Jones said. “But, our hope is that we can shed light on the mechanisms that gave rise to this lead-lag relationship in variability and temperature, and then pass those results on to the modeling community.”

The next chapter

The researchers are cautious to not overstate their results. After all, the sea ice hypothesis is just one of several possible explanations. More evidence is needed.

Some of that evidence may come soon. Jones’ lab has secured funding to reanalyze an ice core extracted in the late 1980s and early 1990s from a site 200 miles south of the East Greenland Ice-Core Project. Using continuous flow analysis, they hope to confirm the patterns Brashear identified and gain further insight into these ancient climate shifts.

“We’re hoping we can replicate the result and push further into modeling,” he said.

The final chapter of Brashear’s research at INSTAAR is now over, but the experience of working in the remote scientific encampment atop the Greenland ice sheet remains vivid. She looks back with fondness on long days in the underground lab, neverending Arctic sun and nights spent celebrating new discoveries with international collaborators.

“It’s awesome to be able to look at a dataset and then have these memories associated with it,” she said. “It helps you stay motivated… I’m still pursuing a career in science, so you could say it had a positive impact.”

A line of national flags waves in the arctic wind. 15 Institutes from 14 different countries participate in research at the East Greenland Ice-Core project. Photo courtesy of Tyler Jones.

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

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Winterized tents house researchers atop the Greenland Ice Sheet at the East Greenland Ice-Core Project. The centerpiece of the camp, a black geodesic dome, and the red mechanic’s garage can be seen in the distance. Photo courtesy of Tyler Jones.

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Cover photo: Winterized tents house researchers atop the Greenland Ice Sheet at the East Greenland Ice-Core Project. A black geodesic dome and a red mechanic’s garage can be seen in the distance.

As mountain glaciers melt, risk of catastrophic flash floods rises for millions − World Day for Glaciers carries a reminder (The Conversation US)

Gabe Allen — Wed, 19 Mar 2025 17:01:45 +0000

As mountain glaciers melt, risk of catastrophic flash floods rises for millions − World Day for Glaciers carries a reminder (The Conversation US) Gabe Allen Wed, 03/19/2025 - 11:01

INSTAAR researcher Alton Byers and Wesleyan University professor Suzanne OConnell highlight research on a global increase in flooding due to melting glaciers. Nearly 2 billion people rely on water from alpine glaciers. But, as the climate warms, they are becoming more volatile.

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Small bird, big trick: How a hummingbird chick acts like a caterpillar to survive (91�� Today)

David J Lubinski — Tue, 18 Mar 2025 18:13:59 +0000

Small bird, big trick: How a hummingbird chick acts like a caterpillar to survive (91�� Today) David J Lubinski Tue, 03/18/2025 - 12:13

When Jay Falk and Scott Taylor first saw the white-necked Jacobin hummingbird chick in Panama’s dense rainforest, the bird biologists didn’t know what they were looking at. They later realized that it was potentially mimicking a poisonous caterpillar to avoid getting eaten.

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Agriculture is main cause of seasonal carbon ups and downs, study finds (CSU)

Gabe Allen — Fri, 14 Mar 2025 12:00:00 +0000

Agriculture is main cause of seasonal carbon ups and downs, study finds (CSU) Gabe Allen Fri, 03/14/2025 - 06:00

A new study in Nature Communications finds that agriculture is the main driver of short-term fluctuations in atmospheric carbon. Led by Danica Lombardozzi (CSU), the research team includes Will Wieder (INSTAAR, NCAR).

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Inside an ice stream (Science)

David J Lubinski — Fri, 14 Feb 2025 03:58:01 +0000

Inside an ice stream (Science) David J Lubinski Thu, 02/13/2025 - 20:58

A hole drilled into Greenland's heart reveals ice ready to slide into the sea. An international group of researchers - including TYLER JONES - discuss their research and its often ominous implications. Don't miss the fantastic photos too!

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International research collaboration uncovers key driver of Himalayan glacier melt

David J Lubinski — Wed, 12 Feb 2025 03:01:58 +0000

International research collaboration uncovers key driver of Himalayan glacier melt David J Lubinski Tue, 02/11/2025 - 20:01

Gabe Allen

Pollution-laden dust storms are depositing black carbon on the Himalayas. New research from INSTAAR’s Karl Rittger and collaborators reveals the process.

Regional pollution is speeding up snow melt in the Indian Himalayas. That’s according to a new study from an international group of scientists including Indian Institute of Technology Madras civil engineering PhD student Amit Singh Chandel and INSTAAR research associate Karl Rittger.

Three of the four largest river basins in the world lie in this region. Understanding this snowmelt is a key question.
- Chandan Sarangi

The study, published in the Journal of Geophysical Research: Atmospheres, reveals how dust storms pick up black carbon from heavily-polluted areas and deposit it in the mountains. Black carbon darkens the ice and snow, causing it to melt faster.

It’s a key insight into a persistent problem. Dwindling ice in the Himalayas has long troubled researchers and decision makers in southern Asia. Nearly two billion people rely on the water produced by Himalayan snowmelt, and glacier loss could lead to water shortages and an increase in extreme floods.

“Three of the four largest river basins in the world lie in this region,” coauthor Chandan Sarangi said. “Understanding this snowmelt is a key question.”

The new study is the result of collaboration across scientific disciplines and international borders. The seeds were planted a few years ago. Sarangi’s lab had already published numerous mathematical models mapping perennial dust storms in Northern India. And they knew that black carbon was getting into the dust somewhere along the way.

In order to paint a clearer picture, Sarangi looked to pair his modeling work with long-term measurements from the field. That’s how he found co-author Rakesh Hooda, a senior research scientist at the Finnish Meteorological Institute. Hooda previously collected nine years of atmospheric measurements at a site in the Himalayan foothills.

Hooda’s data, paired with Sarangi’s models, revealed two distinct types of storms. The first type brews in the deserts of western India and Pakistan and travels east at low elevations. These storms mix with pollution from the heavily-populated Indo-Gangetic Plains before reaching the Himalayas.

You get a darkening of 26% versus 58%. The polluted dust events have double the impact. It’s still a human-induced impact, it’s just not a climate change impact.
- Karl Rittger

The second type of storm starts in the Saharan Desert and travels at higher altitudes. These storms pick up very little pollution.

The new model told the researchers where the dust storms were coming from and what was in them. Now the question was how the storms impact snow and glaciers.

That’s where Rittger came in. In previous research, he had developed a model that could tease apart contributing factors to snow-darkening using satellite imagery. The team applied Rittger’s methodology to the dust storm models and once again validated the findings with on-the ground data.

The results were clear. The storms with high concentrations of pollutants melted more snow.

“You get a darkening of 26% versus 58%.” Rittger said. “The polluted dust events have double the impact.”

Previous research on diminishing glaciers in the Himalayas has often focused on global warming, but the new findings reveal a second, more local cause. To Rittger, it’s a good reminder to look for regional environmental problems that might mimic or coexist with global ones.

“It’s still a human-induced impact, it’s just not a climate change impact,” he said.

The success of this study has all of the co-authors thinking about next steps. Rittger hopes to one day expand his Snow Today website, which provides automated readouts of snow characteristics in the Western US, to Asia. Sarangi hopes to establish more field sites.

“We need more measurements to characterize the aerosols reaching the Himalayas.” He said. “It’s increasing every day.”

Site for measuring aerosol microphysical and optical properties during dust storms, Mukteshwar, Uttarakhand, India. This central Himalayan foothills location is representative and remote, with minimal local emissions. Photo from Chandan Sarangi (IIT Madras).

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

Pollution-laden dust storms are depositing black carbon on the Himalayas. New research from INSTAAR’s Karl Rittger and collaborators reveals the process.

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Research

Deploy, recover, sample, deploy... A day in the life of a CTD Watchstander (GO-BGC)

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Desert reservoirs capture and store organic carbon, according to new research

A carbon sink in the desert

Droughts and floods

Next steps

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This monstrous mama laid the world’s largest egg (National Geographic)

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Drone experiment reveals how Greenland ice sheet is changing (91������ Today)

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Thawing the mysteries of ancient climate changes

New Insights

Ice age heat

The next chapter

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As mountain glaciers melt, risk of catastrophic flash floods rises for millions − World Day for Glaciers carries a reminder (The Conversation US)

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Small bird, big trick: How a hummingbird chick acts like a caterpillar to survive (91������ Today)

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Agriculture is main cause of seasonal carbon ups and downs, study finds (CSU)

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Inside an ice stream (Science)

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International research collaboration uncovers key driver of Himalayan glacier melt

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Drone experiment reveals how Greenland ice sheet is changing (91�� Today)

Small bird, big trick: How a hummingbird chick acts like a caterpillar to survive (91�� Today)