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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鈥檚 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鈥檚 a mathematical formulation of  鈥� 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

鈥淭his 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鈥檛 necessarily get out there and measure it,鈥� Solomon said.

Oleksy's study is the first to test the model against real world data 鈥� 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 .

鈥淚 asked people, 鈥楬ey. I want to test this model, but we need observations from lakes around the world,鈥欌�� 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鈥檚 predictions against the data. The initial test was encouraging.

鈥淭he results were pretty realistic,鈥� she said.

The next step was to make the predictions even better. Through a process called Monte Carlo analysis, Oleksy pitted the model鈥檚 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 鈥� 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鈥檚 future climate and inform large-scale solutions for climate change. These models are vast and complex 鈥� 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.

鈥淭here is a lot of uncertainty about the role of inland waters,鈥� Oleksy said. 鈥淔urther refinements of a model like this might be used to generate estimates of how much carbon is being fixed by lakes annually.鈥�

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 欧美口爆视频 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 欧美口爆视频 River's upper basin. In 2023, the USGS awarded Gooseff鈥檚 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鈥檚 boat-mounted sensors capture data every 40-60 feet. He calls this sampling method 鈥淟agrangian sampling鈥� after the 18th-century mathematician Joseph-Louis Legrange.

鈥淗is 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 鈥� as opposed to sitting somewhere and watching the world change around you.鈥� Gooseff explained.

Gooseff鈥檚 raft, or 鈥渇loating sampling platform鈥� 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 欧美口爆视频 River water as it travels from Rocky Mountain National Park to the canyonlands.

鈥淲hat we鈥檙e trying to do is to figure out, 鈥榳here do we see systematic changes along the river,鈥欌�� Gooseff explained. 鈥淎nd now we have a higher spatial resolution.鈥�

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, 欧美口爆视频, nitrate concentrations in the 欧美口爆视频 River increase. A signal like this is usually the result of agricultural runoff, but water managers weren鈥檛 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鈥檚 data showed that nitrate levels spiked when the Gunnison entered the 欧美口爆视频 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.

鈥淭here鈥檚 a lot of the 欧美口爆视频 River watershed that has the opportunity to modify water quality before it gets to the end of the basin,鈥� 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 欧美口爆视频, Newman can infer where salty groundwater is entering the river.

鈥淭he noble gases are an indicator of where there鈥檚 old groundwater discharge,鈥� Newman explained. 鈥淲e essentially look for the helium to show us where there might be influence of salts because the salinity of the 欧美口爆视频 River is one of the primary management concerns for downstream users.鈥�

If the 欧美口爆视频 becomes too salty, it could prevent lower-basin users in California and Mexico from using the water for agriculture, industry or drinking water. Newman鈥檚 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鈥檚 raft passed through the Black Rocks, a popular swimming, fishing and cliff-jumping spot in Horsethief Canyon, a fisherman waved from a nearby boat.

鈥淵ou all are with the USGS?鈥� he asked. 鈥淚 use your data all the time.鈥�

Because Gooseff鈥檚 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鈥檛 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.

鈥淭he real reward is stepping back after our samples are analyzed and our data comes together and asking 鈥榳hat have we learned,鈥欌�� 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鈥檚 conference runs for a week on 9-13 December in Washington, D.C., and will feature talks and posters from INSTAAR鈥檚 faculty fellows, faculty research associates, postdocs and students. Our Institute鈥檚 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

鈥淭he first ice-free day in the Arctic Ocean could occur before 2030鈥� 鈥� it鈥檚 a stark title for faculty fellow Alexandra Jahn鈥檚 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 C茅line Heuz茅. Read more about this project in 欧美口爆视频 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 欧美口爆视频 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 欧美口爆视频 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 鈥淚cy River鈥� by Boulder-based documentarian Ryan Vachon. .  

Carbon cycling in cold regions

Arctic rivers move, process and store an immense amount of organic carbon 鈥� 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鈥檚 鈥淐hanging Climate: Associated Natural Hazards and Impacts鈥� 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鈥檚 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 欧美口爆视频 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鈥檚 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鈥檚 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鈥檚 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 鈥� 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鈥檚 collaborators at the National Center for Atmospheric Research in Boulder.

鈥淲e鈥檙e 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,鈥� 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鈥檚 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 Ni帽o 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.

鈥淚t can impact how you grow a shell, how quickly your shell dissolves and just your overall survival,鈥� 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.

鈥淚f 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,鈥� Mogen explained. 鈥淢aybe you change how you鈥檙e harvesting fish to allow the ecosystem to make it through an extreme event.鈥�

Mogen鈥檚 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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In an era of dwindling glaciers, Southern Patagonia has managed to hold on to a surprising amount of its ice. But,  from INSTAAR postdoc Matthias Troch and his colleagues suggests that this protective effect might be pushed up against its limits soon.

Before making predictions, Troch and his collaborators looked back in time. They used an equation that, , simulated glacial dynamics for the past six millenia. The results showed that precipitation, not temperature, was the main culprit of glacier fluctuation during around 4,500, of the past 6,000 years, or 76 percent of the time. In more recent years, increased snowfall protected the glaciers from rising global temperatures.

  If we can limit emissions, there is hope for protecting maritime glaciers.

Matthias Troch

These simulations were hyper-focused. The researchers singled out three connected glaciers on the wetter, ocean-facing side of the Patagonia range in Southern Chile. The region came with a distinct scientific advantage. In 2005, a team aboard the American research vessel Nathaniel B. Palmer collected a sediment core from a nearby fjord. Troch and his collaborators got their hands on the sediment core and used it to validate and refine their model. In essence, they had a physical piece of evidence to provide proof that they were on the right track.

Once they had reconciled the numerical model with the sediment core, the researchers began to ask questions about the future. In particular, they were interested in what would happen to the glaciers under different emissions scenarios. If humanity stopped burning fossil fuels today, would the glaciers remain protected? What if we continued to increase our greenhouse gas emissions?

Troch and his colleagues found that increased snowfall would continue to protect the glaciers from melt if regional warming was curbed at 1.5 degrees celsius above turn-of-the-century levels. This benchmark is attainable. Yet, to limit warming to this level, humanity would need to rapidly decarbonize 鈥� temperatures are on track to climb to 2.8 degrees celsius in patagonia by the end of the century if current emissions persist.

鈥淭he study underscores the need for deep emission cuts to protect glaciers, which is vital to limit global sea-level rise,鈥� Troch said.

The researchers also modeled what would happen if we didn鈥檛 cut back, and the outlook was not so sunny. A warmer, wetter climate could lead to rapid melt.

鈥淭his could push glaciers into a new regime dominated by rain rather than snowfall,鈥� Troch explained.

Troch hopes that research like his will bolster the global call-to-action for green policies and practices. While news about the climate is often gloomy, there are still many harms that can be prevented if humanity strives for sustainability.

鈥淚f we can limit emissions there is hope for protecting maritime glaciers,鈥� Troch said.

Troch also hopes that the study will catalyze further research into maritime glaciers around the world. The conclusions drawn in Southern Patagonia might be replicated in Norway, Alaska, Iceland or New Zealand. The only way to find out is further research. 

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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