INSTAAR’s Sarah Crump Graduate Fellowship is now accepting applications from CU Boulder graduate students. Last year’s recipient, Katie Gannon, recalls an eventful summer of field science.

Sarah Crump was a beloved INSTAAR alum. After a hard-fought battle with an aggressive form of cancer, she passed peacefully in November 2022. Before she passed, Sarah designed a fellowship for CU Boulder graduate students studying earth or environmental science in high-latitude or high-altitude regions. The fellowship provides summer funding for one student each year. Women and other underrepresented groups in earth science are particularly encouraged to apply. Preference is given to applicants whose advisors are INSTAAR members. INSTAAR is accepting applications for the 2025 Sarah Crump fellowship now until February 28: Apply, donate or learn more.

As the applications start to roll in for 2025, INSTAAR sat down with Katie Gannon, the recipient of the 2025 Sarah Crump Graduate Fellowship, to hear about her experiences as a fellow. It turns out she had quite an adventurous summer. Sarah would have approved.

You worked on a lot of different projects this summer. Tell us about one that stood out?

At the start of the summer we worked on a research project in the Rawah Wilderness just west of Fort Collins. We were interested in how rock glaciers, which are underground ice formations in the mountains, impact lakes downstream. 

We did two 4-day backpacking trips to get back there and both of them had their share of challenges. The first trip was freezing. We camped in the spring snow and had to post-hole for hours to get between study lakes

On the second trip, we were up high above the tree line when a thunderstorm blew in and it started hailing. We were at least 4 miles from camp, it was the middle of the day and we had at least one more lake to sample before we were done. So we hiked down off the ridge and huddled up in the trees to wait out the storm.

We were all cold and wet and mildly miserable. But then Bella (Gannon’s PhD advisor) started singing and dancing to Chappell Roan’s “Hot to Go!” and we started singing and jumping up and down and dancing to stay warm. I was soaked through, shivering, and laughing hysterically, along with everyone else. It was a great reminder of how important it is to support each other and enjoy the ride.

In the end those trips were a great way to get to know my lab, and the glaciers were so wild to see. The water seeping out of the rock and into the lakes is barely above freezing even in the middle of the summer and it is laden with ions and trace minerals.

You also worked on lake monitoring efforts in Rocky Mountain National Parks and in Green Lakes Valley. Tell us about that.

These long-term projects feel special to me because in addition to creating useful data, repeatedly visiting these sites allows us to get to know the lakes and develop a connection with them. Last season, I watched  thaw bloom in the spring. Then, in the fall, I watched as the trees lost their leaves and the lake froze over again.

We deploy buoys in the lakes that measure temperature and dissolved oxygen concentration. In the winter, the ice freezes over the top and the buoy is pushed down about a meter below the surface. Even though we carefully map out where each one is in the fall, the ice inevitably pulls them around during the colder months.

On one of my first field days this summer we hiked our boats in four miles to the Loch and then spent two more hours paddling in circles looking for our buoy. Everyone cheered when we finally found it. 

Gannon's field photos (click to zoom)

Your lab collaborated with the forest service this summer. Tell us about that.

We looked at two remote mountain lakes in the San Juan Mountains that are experiencing algal blooms. This, in and of itself, is strange. You don’t usually see algal blooms in watersheds that have been minimally impacted by people. 

In order to get all our gear in to collect samples, our team brought in a team of six mules and horses. They were hilarious and adorable. We would just sit in camp in the evening and watch them play around in the pasture. Having help from the pack animals and forest service amplified the project. We were able to collect much more data than we would have on our own.

You were busy this summer. Did you have time to work on your own research?

Yes. I got the first project for my PhD off the ground. I’m investigating methane and carbon dioxide accumulation in two alpine lakes. One is above the treeline while the other is below. 

The fellowship allowed me to scout out lakes, order materials and find collaborators here at CU to help me run my samples. Now I have two months of data. We’re also collecting samples through the winter to see if methane and carbon dioxide build up under winter ice. 

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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A refined mathematical model is now capable of predicting carbon inputs and outputs for freshwater lakes around the world, according to new research from INSTAAR’s Isabella Oleksy and collaborators. Their work could help scientists understand the role of freshwater lakes in the global carbon cycle.

Oleksy's most recent paper, which was published, tests and revises an equation that allows scientists to estimate the overall biological activity in a lake from limited data.

The equation  by a group of scientists, including Oleksy's co-author , in 2018. It’s a mathematical formulation of  — a longstanding theory in the field. Basically, the theory posits that you can estimate the total growth of phytoplankton in a lake from the color of the water and measurements of a few key nutrients. Phytoplankton is the basis of the marine food web, which makes it a good stand-in for lake productivity on the whole.

  Further refinements of a model like this might be used to generate estimates of how much carbon is being fixed by lakes annually

-- Isabella Oleksy

“This is a way to potentially be able to understand what algal biomass and water quality might look like in a bunch of different lakes, even when you can’t necessarily get out there and measure it,” Solomon said.

Oleksy's study is the first to test the model against real world data — quite a bit of it. Back in 2019, when Oleksy was a postdoctoral researcher at the , she put out a call for data at a meeting of the .

“I asked people, ‘Hey. I want to test this model, but we need observations from lakes around the world,’” she said.

Collaborators were eager to help out. With the help of 30 scientists at many different institutions, Oleksy gathered detailed measurements from 58 different freshwater lakes around the world. Then, she tested the model’s predictions against the data. The initial test was encouraging.

“The results were pretty realistic,” she said.

The next step was to make the predictions even better. Through a process called Monte Carlo analysis, Oleksy pitted the model’s predictions against the on-the-ground data. Where the model faltered, she added new parameters to improve it.

In the end, Oleksy and her collaborators created a model capable of estimating the conditions of freshwater lakes in a diverse range of locations and ecosystems.

According to Oleksy, the new model could have implications far beyond freshwater lakes. It elucidates one small element of the global carbon cycle — a cycle that has become a priority for scientists in the era of global warming.

Policy makers and researchers rely on global-scale models of the carbon sources and sinks to predict the Earth’s future climate and inform large-scale solutions for climate change. These models are vast and complex — they must take into account the inputs and outputs of diverse human activities, ecosystems and geologic phenomena. Oleksy and her collaborators hope that their new study can be used to eliminate some uncertainty from these estimates.

“There is a lot of uncertainty about the role of inland waters,” Oleksy said. “Further refinements of a model like this might be used to generate estimates of how much carbon is being fixed by lakes annually.”

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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Michael Gooseff and collaborators are gathering the first-ever continuous, long-term water quality sample of the Colorado River's upper basin. INSTAAR senior communication specialist Gabe Allen joined them for three days on the river.

One vessel in particular stood out from the rafts of vacationers and fisherman that floated lazily through Ruby Canyon on a sunny fall day last month. The occupants had swapped the usual fish and tackle for binders, laptops and an assortment of pumps and devices all buckled together with ratchet straps.

Aboard the raft, U.S. Geological Survey groundwater hydrologist bottled river water samples and jotted down notes in a waterproof notebook. Behind him, INSTAAR faculty fellow Michael Gooseff manned the oars and kept a watchful eye on a collection of sensors strung on a pole that extended into the water from the back of the boat.

This is the tenth time Gooseff and his collaborators have rafted this stretch of river since 2018. The goal is to gather the first-ever continuous, long-term water quality sample of the Colorado River's upper basin. In 2023, the USGS awarded Gooseff’s team with funding for biannual surveys through 2026.

A new approach

While water quality data is usually limited to discrete monitoring stations posted every few miles along the river bank, Gooseff’s boat-mounted sensors capture data every 40-60 feet. He calls this sampling method “Lagrangian sampling” after the 18th-century mathematician Joseph-Louis Legrange.

“His idea was that you could take the perspective of a moving particle in the world and try to understand how it changed based on its surroundings — as opposed to sitting somewhere and watching the world change around you.” Gooseff explained.

Gooseff’s raft, or “floating sampling platform” as he likes to call it, is equipped to measure pH, temperature, conductivity, turbidity, dissolved oxygen and nitrate. Collectively, these measurements offer a detailed map of the character and contents of Colorado River water as it travels from Rocky Mountain National Park to the canyonlands.

“What we’re trying to do is to figure out, ‘where do we see systematic changes along the river,’” Gooseff explained. “And now we have a higher spatial resolution.”

Pinpointing water quality

The project has already reaped insights. In 2019, . The researchers were able to pinpoint sources of salts, nitrogen, turbidity and temperature fluctuation over time and space.

One particular finding offered important insight to river users. Somewhere around Grand Junction, Colorado, nitrate concentrations in the Colorado River increase. A signal like this is usually the result of agricultural runoff, but water managers weren’t sure exactly where the nitrate was coming from. Was it from the confluence with the Gunnison River, which hosts large farms upstream? Was it from local farms in the Grand Valley?

Gooseff’s data showed that nitrate levels spiked when the Gunnison entered the Colorado and then continued to climb as the river moved through the Grand Valley. The study elucidated, for the first time, how much nitrate was contributed by each source.

Gooseff hopes that findings like these can help water and land managers better solve issues as they arise. The upper basin is especially important because changes in water quality here can compound as the water travels to lower-basin states like California. Nitrate, which can lead to harmful algal blooms in high enough concentrations, is just one example.

“There’s a lot of the Colorado River watershed that has the opportunity to modify water quality before it gets to the end of the basin,” he said.

Understanding groundwater

This year, the floating sampling platform featured a new gadget. Newman brought along a portable mass spectrometer called a  that is capable of detecting precise concentrations of noble gases, like helium or argon, in the water.

The miniREUDI was more expensive than everything else in the boat combined, and is one of only two in the U.S., but it was worth it. By tracking helium along the Colorado, Newman can infer where salty groundwater is entering the river.

“The noble gases are an indicator of where there’s old groundwater discharge,” Newman explained. “We essentially look for the helium to show us where there might be influence of salts because the salinity of the Colorado River is one of the primary management concerns for downstream users.”

If the Colorado becomes too salty, it could prevent lower-basin users in California and Mexico from using the water for agriculture, industry or drinking water. Newman’s data will give water managers more information that they can use to map and prevent excess salinity.

Newman, Gooseff and other collaborators outlined their methodology and rationale for using miniREUDI in the boat . They hope to publish more results soon.

Click to zoom

Packing up

As Gooseff’s raft passed through the Black Rocks, a popular swimming, fishing and cliff-jumping spot in Horsethief Canyon, a fisherman waved from a nearby boat.

“You all are with the USGS?” he asked. “I use your data all the time.”

Because Gooseff’s research is funded by the USGS, any papers or datasets that come from it will be freely available to the public. The insights will be invaluable for land and river managers like the Bureau of Land Management. With any luck, they could help especially science-literate fishermen find a new honey hole as well.

By now, the floating sampling platform, oars and camping gear are packed away for the winter. But, it won’t be long before Gooseff heads back up to the Pumphouse Boat Launch to run the river during the high-flow spring season. As much as he relishes long days in the field and nights spent under the moonlight, the quiet months are just as interesting.

“The real reward is stepping back after our samples are analyzed and our data comes together and asking ‘what have we learned,’” he said. 

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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Each year, more than 25,000 earth and space scientists from around the world convene for the annual convention of the American Geophysical Union. This year’s conference runs for a week on 9-13 December in Washington, D.C., and will feature talks and posters from INSTAAR’s faculty fellows, faculty research associates, postdocs and students. Our Institute’s contributions will span the globe, touching on Earth systems in the oceans, alpine and polar regions.

Research highlights, from Monday to Friday

Click any image to zoom

A sea-ice free arctic

“The first ice-free day in the Arctic Ocean could occur before 2030” — it’s a stark title for faculty fellow Alexandra Jahn’s latest paper, . Jahn will give an invited talk about her research during a Monday session. In it, she will detail her work to model the climatic conditions that could lead to an ice-free arctic in the near future. Her collaborator on this project was the Swedish earth scientist Céline Heuzé. Read more about this project in CU Boulder Today.   

Woody encroachment into alpine tundra

Although woody encroachment has been well-studied in the arctic, less is known about its effects in alpine tundra. Katya Jay (INSTAAR affiliate and alum, now at NEON and CU Boulder ESIL) and her co-authors have combined multiple imagery datasets with many other measurement types to try to understand how encroachment happens over time. The team included Katharine Suding, Will Wieder, and two CU Boulder colleagues. Jay will present their findings in a poster session on Tuesday. For more about her recent research, .  

Alpine lake biomarkers in Wyoming

Lipid biomarkers preserved in lake sediment provide valuable information about past climate and environmental changes. One such class of biomarkers, brGDGTs, has proven its value as a paleothermometer and has promise for reconstructing other key environmental variables as well. INSTAAR research scientist Jonathan Raberg (also with University of Wyoming) will present his collaborative work to compare sediment brGDGTs with other environmental proxies in Wyoming alpine lakes.  

Warming and sediment on the Canning River

Faculty fellow Irina Overeem - with a team of mostly INSTAAR researchers, alums, and affiliates - spent the past two field seasons documenting changes on the Canning River in Alaska. She will speak about their research on Tuesday. The project investigates the transport of sediment and nutrients from the Alaskan permafrost out to the Arctic Ocean. Overeem and PhD student Josie Arcuri are also the stars of a new film about the project titled “Icy River” by Boulder-based documentarian Ryan Vachon. .  

Carbon cycling in cold regions

Arctic rivers move, process and store an immense amount of organic carbon — carbon that has built up in the surrounding permafrost over millennia. Faculty fellow Suzanne Anderson will present a poster on Tuesday detailing her work to elucidate the carbon cycles, sources and sinks of these icy waterways. Her research sheds light on these poorly-understood systems during a time when climate change is impacting them on every level. Her collaborators include Irina Overeem, Robert Anderson, Marisa Repasch and Josie Arcuri.   

Snowmelt and subalpine forests

As the climate warms, subalpine forests experience longer growing seasons and more variable winter snow. In an invited talk on Thursday, faculty fellow Noah Molotch will detail his investigation into these important ecosystems over the past quarter-century. His work draws on decades of remote sensing data that shows the importance of snowmelt on ecosystem productivity. His collaborators include Eric Kennedy, John Knowles, Sean Burns and Peter Blanken.  

Marine heatwaves and ocean acidity extremes

PhD student Samuel Mogen, Nikki Lovenduski and collaborators take aim at predicting marine heatwaves and ocean acidity extremes in a . Their new model is adept at forecasting these acute events from months to a year in advance, with varying degrees of certainty based on the event type and location. Mogen will present the team's poster on Thursday in a session on climate variability and predictability. Read more about the forecasts in a recent INSTAAR news story.  

Flooding in the 21st Century

Faculty fellow Albert Kettner will give an invited tallk on Thursday during AGU’s “Changing Climate: Associated Natural Hazards and Impacts” session. He will focus on . His research documents changes in the magnitude and frequency of flooding under a specific climate scenario, in which emissions are reduced slowly. His collaborators include Sagy Cohen, Irina Overeem, Balazs Fekete, Robert Brakenridge and Jaia Syvitski. Read more about Kettner’s work in a recent INSTAAR news story.  

Microbes and methane growth 2020-2022

A new analysis from Sylvia Michel, Pieter Tans, Reid Clark, Jianghanyang (Ben) Li, and collaborators investigates the root cause of a recent atmospheric methane spike. Their finding suggests microbes have been emitting more methane than fossil fuels in recent years. Nonetheless, reducing fossil fuel consumption remains key to addressing climate change. Their work was recently . Michel will give an invited talk on Friday in a session on Isotopes of the Atmospheric Components. Read more about this study in CU Boulder Today

Mountain hydrology and biogeochemistry

Presentations on 'Mountain hydrology and biogeochemistry in a changing world' are being held in honor of (INSTAAR Fellow Emeritus and Geography Professor Emeritus), who passed away in 2023. Presenters are invited to build on Mark's diverse contributions and address the question: What’s next for mountain hydrology? A total of 25 presentations will be made. Noah Molotch is the primary convener, assisted by Diane McKnight and Jennifer Morse, plus INSTAAR alums Paul Brooks (University of Utah) and Alia Khan (Western Washington University).    

Special events

Click any image to zoom

Monday 4:00 - 5:00 p.m. Exhibit Hall booth #328

Meet the editors of INSTAAR's journal AAAR

INSTAAR's peer-reviewed, open-access journal will be represented in booth #328 in the Exhibit Hall during the meeting. Stop by on Monday late afternoon to meet with our journal editors Anne Jennings and Diane McKnight as well as the staff at Taylor & Francis who publish and host the journal. AAAR primarily covers environmental science from modern to paleo timescales, with an emphasis on climate change in mountain and high latitude regions.

Monday 5:30 - 7:00 p.m. Dacha Beer Garden

Attend the INSTAAR happy hour

Our NewSTAAR committee is hosting an informal INSTAAR happy hour on Monday evening. All INSTAARs are invited, both current folks and alumni. Grad students and postdocs are especially encouraged to attend. The event will be held at the Dacha Beer Garden (Shaw, 1600 7th St NW #7), which has a variety of drink/food options and is within walking distance to the convention center. Committee members will be there until about 7:00 p.m., so drop by when you can.

Wednesday 6:00 - 8:00 p.m. Hall E

Celebrate INSTAAR's latest AGU Fellow

Michael Gooseff is among 54 scholars in the 2024 cohort of AGU Fellows. All have made exceptional contributions to their fields and will be celebrated at the Honors Ceremony on Wednesday evening in Hall E of the Convention Center (subsequent banquet requires a ticket and is in a different location). The honor is bestowed annually on less than one tenth of one percent of AGU members. Gooseff was selected for his exemplary leadership and for advancing our understanding of how a changing climate affects ecosystems and freshwater supply. Read more about Mike and his recognition in an INSTAAR news story.  

Additional presentations

More than 85 INSTAARs are participating in AGU 2024. Click an author name below to see their abstracts on the AGU website. For questions, email David Lubinski.

Categories

Each author’s name is followed by a bracketed number (signifying the number of abstracts they contributed to) and a series of short letter codes (signifying topics). The topic codes are as follows:

• A  Atmospheric Sciences
• B  Biogeosciences
• C  Cryosphere
• EP  Earth & Planetary Surface Processes
• ED  Education
• GP  Geomagnetism, Paleomagnetism & Electromagnetism
• GC  Global Environmental Change
• H  Hydrology
• NH  Natural Hazards
• NS  Near Surface Geophysics
• OS  Ocean Sciences
• PP  Paleoceanography & Paleoclimatology
• SY  Science & Society
• TH  Town Hall
• U  Union Session

INSTAAR authors 

[#] = Number of abstracts per author

• [1] B
• [10] C, EP
• [6] C, EP
• [1] PP
• [1] H
• [3] EP
• [17] B, EP, H, NS
• [2] C, PP
• (alum) [5] GC, H, SY, TH
• [1]
• [2] B, SY
• [1] C
• [1] A
• [2] EP
• [1] H
• [1] OS
• [3] EP
• [2] A, SY
• [2] C, OS
• [7] GC, H, SY
• [1] H
• (alum) [2] PP
• [1] C
• [1] H
• [1] EP
• [4] GC, PP
• [4] H, NS
• [2] GC, SY
• [8] C, GP, PP
• [2] B, C
• [1] H
• [1] U
• + [5] ED, EP, NH
• [1] H
• [1] C
• [2] SY
• [3] C, H
• [6] A
•  [2] C
• [4] A, B, 
• [1] B
• + [4] B, PP
• [10] C, ED, PP
• [6] B, H, 
• [8] A, B, SY
• [1] PP
• [4] A, OS, 
• [9] C, GC, H, U
• [4] C, OS
• [1] B
• + [3] H
• [11] A, B, C, GC, H, NS, SY
• [1] B
• [3] H
• [10] C, ED, EP
• [7] C, H
• [1] H
• [3] H
• + [2] H
• [3] C, EP
• [2] PP
• [4] EP, PP
• + (alum) [13] B, EP, H
• [1] SY
• [14] C, GC, H
• [5] B
• [2] B, C
• [2] C
• (alum) [1] PP
• [1] A
• [3] GC, PP
• [1] C
• [5] B, OS
• [2] B, GC
• [1] B
• [3] A, SY
• [3] B, H, NS
• [2] SY
• [1] C
• [1] B
• [1] SY
• [1] SY
• [10] B, GC, H
• [2] H
• [2] B, NS

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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In the 21st century, the Earth’s oceans are growing warmer and more acidic. This change is happening slowly over the long-term, but it can also cause short-term, local spikes.

These events are like the heatwaves and or bad air quality days we experience here on land, they just happen underwater. And, if they are bad enough, they can devastate marine ecosystems.

INSTAAR PhD student Samuel Mogen, INSTAAR director Nicole Lovenduski and collaborators take aim at these ocean extremes . The researchers outline a method for forecasting both marine heatwaves and acute ocean acidity. The new model is adept at forecasting these events up to year in advance, with varying degrees of certainty based on the location.

Though Mogen and his collaborators , they are the first to forecast ocean acidification. In the past, this research has been stymied by a lack of data — acidity is much harder to measure than temperature. While satellites can accurately measure sea surface temperature from above, acidity levels can only be measured by collecting physical water samples.

However, in recent years, scientists have been hard at work entering measurements from research cruises into large earth system models like the one Mogen used. Much of this research has been contributed by Mogen’s collaborators at the National Center for Atmospheric Research in Boulder.

“We’re getting to the point where we can use them to try and understand the evolution of carbon in the ocean in the short-term future,” Mogen said.

Carbon is key for understanding ocean acidity, especially in the 21st century. As global emissions increase, more and more carbon dioxide leaches into seawater from the atmosphere, making it more acidic. Mogen’s model predicts, for the first time, how large-scale climate patterns might impact this effect.

In one example, the researchers found that the recurring warming event in the central and eastern tropical Pacific Ocean called an El Niño seems to lead to widespread ocean acidity. This effect is especially pronounced in the eastern pacific, off the coast of the Americas.

Mogen and his collaborators used a mineral called aragonite as a proxy for ocean acidification. As acidity goes up, aragonite concentrations go down. And, this change has a direct effect on marine organisms. Mollusks, like clams and snails, and corals rely on aragonite to form shells and exoskeletons. Without it, they are left unprotected.

“It can impact how you grow a shell, how quickly your shell dissolves and just your overall survival,” Mogen explained.

This is just one of the myriad ways that ocean acidity affects marine life. Many are still being discovered.

As acute ocean acidification events worsen, Mogen hopes that his research will pave the way to better forecasting and more sustainable management of marine ecosystems.

“If you can predict these events in advance, you might be able to inform a manager of a regional fishery and they can alter their practices,” Mogen explained. “Maybe you change how you’re harvesting fish to allow the ecosystem to make it through an extreme event.”

Mogen’s paper is fresh off the (virtual) presses, but the researchers actually put the finishing touches on their model a year ago. Back in November of 2023, they produced a forecast for the upcoming year that foretold widespread marine heatwaves and ocean acidity.

Mogen says that, at first glance, the heat wave predictions seem to have played out. But, it will take a while longer to crunch incoming data on acidity. As new information flows in, the researchers will dive back in and further validate the model. In the end, they hope to give decision makers the best possible tools to predict ocean extremes and mitigate their impacts.

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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