Spotlight Postdoc

Scientists predict a sea change in Arctic ecosystems by the end of the century

Gabe Allen — Wed, 19 Nov 2025 13:00:00 +0000

Scientists predict a sea change in Arctic ecosystems by the end of the century Gabe Allen Wed, 11/19/2025 - 06:00

Gabe Allen

The lush greenery of the Amazon rainforest is often called the “lungs of the planet,” but really land plants are just half of the equation. The other lung dwells in the sea. Single-celled photosynthetic algae, known collectively as phytoplankton, produce about half of the oxygen in Earth’s atmosphere.

Phytoplankton are especially abundant at high latitudes, where seasonal sea ice retreat leads to explosive summer blooms.

“Polar regions can experience rapid growth,” INSTAAR postdoctoral fellow Courtney Payne explained. “They have a pretty short window, but phytoplankton can grow like crazy over a period of weeks or months.”

According to a new paper from Payne and collaborators, that cycle may soon be disrupted in the Arctic Ocean. Using a suite of modeling tools, the researchers predicted the state of phytoplankton blooms 80 years into the future — in the year 2100 — and compared them to records from the 1970s. They found that summer blooms will start more than a month earlier on average by the end of the century.

Unfortunately, the models predict that this change in seasonal timing will disrupt the foundation of the marine food web, leading to scarcity at every trophic level. It’s a change that will impact marine animals and the Indigenous communities that rely on them for sustenance.

Payne kneels on sea ice in the Chukchi Sea during a research cruise in 2023. (Courtesy, Courtney Payne)

Mismatches in the food web

The first time Payne saw a phytoplankton bloom, she was behind a pair of oars in a boat off the coast of Maine. It was just another day of practice for her collegiate rowing team, but the water, which had remained deep blue all winter, had turned green.

“Each spring, someday it would turn this violent green color,” Payne said. “Several years we would have these big swarms of jellyfish come through to consume the phytoplankton.”

These days, Payne spends most of her working hours behind a computer, but her history on the water allows her to visualize the ecosystems she studies. Just like the jellyfish in Maine, phytoplankton in the Arctic provide food for drifting grazers known collectively as zooplankton. This interaction forms the base of a rich marine food web. The zooplankton feed fish and whales, and the nutrients trickle their way up to seals, sea birds, polar bears and other Arctic animals.

The earlier spring bloom predicted by Payne and her collaborators may not seem like a bad thing. In fact, the researchers predict that the bloom will last more than a month-and-a-half longer on average by the end of the century. But, marine organisms have adapted to the current cycle over millennia, and they are ill prepared for it to change so quickly and drastically.

The researchers predict that scarcer sea ice will lead phytoplankton to bloom during the cold early-summer months. Zooplankton struggle to multiply at these temperatures and thus will not be able to take advantage of the bounty. Each spring, a large proportion of the bloom will go uneaten and sink to the ocean floor.

“If the spring bloom happens earlier and at these colder temperatures, the things that feed on the phytoplankton aren’t able to grow as much in response,” Payne said. “That means that whales and other animals that migrate to the area won’t have as much food to feast on.”

Maps of the Arctic Ocean showing the change in the average start date of the spring phytoplankton bloom from 1970 to 2020 (left) and from 1970 to 2100 (right). So far, the change has been subtle, but Payne and her collaborators predict a much earlier bloom by the end of the century. (Courtesy of Courtney Payne)

The culprit is clear

Overall, the new study paints an alarming picture for the future of Arctic marine ecosystems. But, there is a silver lining. Payne and her collaborators proved the efficacy of a methodology seldom seen in ecological research.

While previous studies have relied on limited observational data or single model simulations, the new study took a more comprehensive approach. The researchers worked off of an Earth system model that had been tweaked 50 times to produce 50 different, equally likely, future scenarios.

“If we used real world observational data, we would have to rely on one example of what the Earth is doing over a short period, which may not be representative of changes in the long run,” Payne said. “One of the benefits of using an Earth system model is that you can run the same years over and over again and use the mean to figure out, on average, what is going on.”

By comparing this “ensemble” of outcomes, the researchers were able to separate out the effects of anthropogenic climate change from natural climate variability. In short, they could identify a culprit: greenhouse gas emissions.

“With our methodology, we are able to specifically isolate the impact of climate change on the timing of the bloom,” Payne said. “Thus far it has only led to a shift of about 5 days, but we see a much more substantial impact by the end of the century.”

INSTAAR director Nicole Lovenduski, NCAR scientists Alice Duvivier, Marika Holland and Kristen Krumhardt are coauthors on this report.

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.

A team, led by INSTAAR’s Courtney Payne, used a powerful methodology to predict outcomes for life in the Arctic Ocean in the year 2100. Their results predict disrupted phytoplankton blooms, which will ripple throughout the ecosystem.

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A phytoplankton bloom in the Barents Sea, north of Norway and Russia, as seen from space in July, 2021. (NASA Earth Observatory)

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A phytoplankton bloom in the Barents Sea, north of Norway and Russia, as seen from space in July, 2021. (NASA Earth Observatory)

North Atlantic dolphins are dying younger, new study shows (CU �� Today)

Gabe Allen — Mon, 13 Oct 2025 22:53:58 +0000

North Atlantic dolphins are dying younger, new study shows (CU �� Today) Gabe Allen Mon, 10/13/2025 - 16:53

Common dolphins in the Bay of Biscay aren't living as long as they were in the '90s, according to a new paper led by INSTAAR postoc Etienne Rouby. The study used a novel sampling method to update inaccurate estimates and propose solutions.

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Embracing excellence: CU �� honors postdocs and mentors during National Postdoc Appreciation Week (Postdoctoral Affairs)

David J Lubinski — Mon, 22 Sep 2025 17:55:06 +0000

Embracing excellence: CU �� honors postdocs and mentors during National Postdoc Appreciation Week (Postdoctoral Affairs) David J Lubinski Mon, 09/22/2025 - 11:55

Among a select group to receive awards were two INSTAARs: Nathalie Vriend was selected as a CU �� Outstanding Postdoc Mentor of the Year and Edgart Flores won an honorable mention as an Outstanding Postdoc. Congratulations to both of them!

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A conversation with Jonathan Henn, 2024 CU �� postdoc of the year

David J Lubinski — Fri, 10 Jan 2025 19:54:41 +0000

A conversation with Jonathan Henn, 2024 CU �� postdoc of the year David J Lubinski Fri, 01/10/2025 - 12:54

Gabe Allen

Jonathan Henn has quickly become an eminent plant ecologist with work on alpine plant communities and grassland wildfires. He reflects on his research journey so far.

Jonathan Henn

This fall, Vice Chancellor for Research and Innovation and Dean of the Institutes Massimo Ruzzene named INSTAAR’s Jonathan Henn an Outstanding Postdoc of the year. The award recognizes only two postdoctoral scholars from the entire CU �� system each year. Henn was chosen for his excellence in research productivity, innovation, communication, leadership, and advocacy for justice, equity, diversity, and inclusion.

During his postdoc, Henn is working with INSTAAR faculty fellow Katharine Suding to characterize long-term change in alpine plant communities and study fire regimes in grasslands. Though he is an early-career scientist, he has published 26 peer-reviewed papers and secured over $700,000 in research funding. Several of his recent papers have been cited over 100 times.

As Henn’s time as a postdoc nears its end, INSTAAR sat down with the hard-working young scientist to reflect on his research journey.

Did you always want to be an ecologist? How did you find your way to studying plant communities?

I'm from Minnesota and my family had a lake cabin up in northern Wisconsin. As a kid, I spent a lot of time out in the woods just running around finding cool plants. Going into college, I already thought biology was really cool. At first I thought birds were my thing. But then, for my first summer internship, I did restoration monitoring in natural areas around campus. It hooked me, and it all just went from there.

It's an awesome job, I think, because you get paid to go to all kinds of really interesting places and just try to figure out what's going on. Hopefully your work leads to a better understanding of these natural systems. And, if you better understand how things are happening, you might be able to manage and restore ecosystems in a way that can preserve nature.

Working high up on Niwot Ridge, Colorado

You’ve published a ton of work during your time at INSTAAR. What is a highlight?

We just published a paper on alpine plant responses to climate change that represents a large part of my postdoctoral work. We found that things are changing in a really wide variety of ways.

The difficult thing that a lot of researchers have encountered is that alpine plants live for a long time and are relatively slow to respond to things. That's one of the really awesome things about the Niwot Ridge Long-Term Ecological Research Project. We have really long term datasets that can start to capture these slow responses.

Subalpine meadow, Colorado.

It’s still messy — different plant species are responding in different ways. But one way that we can cut through that variation is by thinking about characteristics of plants that might relate to the way that they grow, survive, and experience their environment. You can sort of characterize plants as having more of a live fast, die young strategy where they grow really fast and don't live as long. Other plants have a more conservative, slow-growing strategy, and these species are very common in Alpine and Arctic environments.

When you start to split it up like that, you start to see patterns. It seems that the live fast, die young plants are having more success under global change conditions. On the other hand, the really stress tolerant, slower growing plant species are tending to decline through time.

What are you most proud of during your time as postdoctoral scholar with INSTAAR?

I've worked with a really wide variety of people and a wide variety of projects, and that's been really satisfying. It all stems from my involvement with Niwot Ridge. There's so many awesome people doing really cool things.

Recently I've been really involved in this grassland fuels project. People from the �� city and county governments came to my advisor, Katie Suding, after the Marshall fire. They were under a lot of pressure to figure out how to prevent it from happening again. They were looking for a way to manage the grasslands in a way that could reduce wildfire risk. Katie realized that we don't really know anything about the efficacy of different management strategies and what sort of side effects they might have.

It’s a unique project because it came from this specific question and need that managers had. We wrote a proposal, got a grant funded, and that’s been my focus for the last year-and-a-half or so. Now we’re getting a big project off the ground that's super collaborative. We’re integrating folks in �� as well as Louisville and Superior and Longmont. It’s been a really interesting experience doing research that's management focused and has, hopefully, very actionable outcomes.

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.

Jonathan Henn has quickly become an eminent plant ecologist with work on alpine plant communities and grassland wildfires. He reflects on his research journey so far.

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Annika Horlings: Icy reflections: Fieldwork and the calling to study glaciers (USPECS)

David J Lubinski — Tue, 26 Nov 2024 18:30:39 +0000

Annika Horlings: Icy reflections: Fieldwork and the calling to study glaciers (USPECS) David J Lubinski Tue, 11/26/2024 - 11:30

From serene Alaskan glaciers to harsh Antarctic winds, postdoc Annika Horlings shares her journey as a glaciologist exploring icy landscapes. Her research focuses on polar near-surface processes that are important in the mass balance of alpine glaciers and ice sheets, how these processes work, and how they are changing through time.

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Chancellor's Postdoctoral Fellowship for Faculty Diversity 2024 (RIO)

Anonymous — Tue, 23 Jul 2024 06:00:00 +0000

Chancellor's Postdoctoral Fellowship for Faculty Diversity 2024 (RIO) Anonymous (not verified) Tue, 07/23/2024 - 00:00

Peyton Thomas (INSTAAR & ENVS) is one of three awardees of the 2024-25 Chancellor's Postdoctoral Fellowship for Faculty Diversity. She will study fish ecology along the Yukon River in Alaska, improving physiological and behavioral understanding. Additionally, she will use her platform as an elite athlete to advocate for environmental and social change across academia, industry and government.

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Take 5 with Michael Dyonisius

Anonymous — Tue, 30 Apr 2024 21:32:20 +0000

Take 5 with Michael Dyonisius Anonymous (not verified) Tue, 04/30/2024 - 15:32

Five questions and answers with Michael Dyonisius, a postdoc with INSTAAR’s Laboratory for AMS Radiocarbon Preparation and Research, a keen investigator of greenhouse gas fluxes, and an occasional ukulele-playing indie pop fan. Read on to learn about Michael’s work, inspirations, and life.

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Scientist, Olympic hopeful runs with real purpose (Colorado Arts & Sciences Magazine)

Anonymous — Tue, 30 Jan 2024 07:00:00 +0000

Scientist, Olympic hopeful runs with real purpose (Colorado Arts & Sciences Magazine) Anonymous (not verified) Tue, 01/30/2024 - 00:00

Clay Bonnyman Evans

CU �� postdoctoral researcher Peyton Thomas, who fuses running with a commitment to environmental causes, to compete in U.S. Olympic women’s marathon trials in February.

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A passion for science and the outdoors fuels one woman’s drive to combat climate change (Rocky Mountain PBS)

Anonymous — Thu, 21 Jul 2022 06:00:00 +0000

A passion for science and the outdoors fuels one woman’s drive to combat climate change (Rocky Mountain PBS) Anonymous (not verified) Thu, 07/21/2022 - 00:00

INSTAAR postdoctoral scholar Peyton Thomas loves being in nature, but as a scientist she is well-aware of the threat climate change poses to our environment. She also hopes to inspire the next generation of Black women scientists.

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Mette Bendixen receives the AGU Science for Solutions Award

Anonymous — Wed, 11 Nov 2020 07:00:00 +0000

Mette Bendixen receives the AGU Science for Solutions Award Anonymous (not verified) Wed, 11/11/2020 - 00:00

The American Geophysical Union has announced that INSTAAR postdoctoral scholar Mette Bendixen is the recipient of their 2020 Science for Solutions Award.

The Science for Solutions Award is given annually to a student or postdoctoral scientist in recognition of significant contributions in the application and use of the Earth and space science to solve societal problems.

The award follows Bendixen’s out-of-the-box work on an overlooked global challenge: the scarcity of sand resources.

Bendixen’s research was focused on understanding how coasts of Greenland respond to change processes induced by climate change. She said, “Our research has proven that as the Greenland Ice Sheet melts, it’s not only water that drains into the ocean. Massive amounts of sand are deposited along the coast in deltas, actually causing the coast of Greenland to extent further into the sea (prograding). This is exactly opposite of a majority of the Arctic coasts, that erode due to permafrost thaw, increasing open-water season, and increased wave erosion. To put it a little simplisticly, you can say that Greenland is growing bigger simply because massive amounts of sand are transported through meltwater rivers and deposited along the coast.”

Soon after publishing a paper on prograding Greenland deltas, Bendixen was surprised to learn the extent of the world’s need for sand. “At the same time, I was stunned to see how little scientific focus this critical topic had,” she said. “I mean, after water, sand is the most extracted natural resource on Earth. And this extraction can have huge consequences for human and nature—all while it provides key building blocks for our modern society.”

The thought wouldn’t let go: could Greenland’s sand supply an increasingly starving world market?

An exploration of the topic led to a string of high-impact journal articles and an interactive feature and front-page story in the New York Times.

Bendixen said the implications of sand export from Greenland for the environment, carbon emissions, and tourism would need to be considered carefully before Greenland decides to go forward with the idea. “There really are numerous questions that must be fully understood in order for Greenland to decide if to exploit this material,” she explained.

But she insists the decision should rest with the people of Greenland. “Who am I to say that Greenland should or shouldn’t use their natural resources?” she asked. “I want to learn about Greenland’s own opinion on this.” Bendixen has received funding from the Danish Carlsberg Foundation to conduct a national household survey in Greenland to ask about opinions on a potential sand industry.

Irina Overeem, INSTAAR Fellow and Deputy Director of the Community Surface Dynamics Modeling System, works closely with Mette and recommended her for the AGU award. She said, “Mette is a highly creative scholar, but what really sets her apart is her drive to further her ideas with other experts. She posed this unusual question straddling science domains, in this case global change to sedimentary geology to economy to sustainability science. She then reached out to domain experts and discussed the ideas and brings them back into a paper. It was immediately policy-relevant for Greenlandic society; I found it being discussed in the economy section of Sermitsiaq, the national Greenlandic paper, while there on summer fieldwork.”

Bendixen said, “I have to be honest and say, that when I started working as a Research Fellow at INSTAAR in 2018 with Associate Professor Irina Overeem, I didn’t think I’d end up doing research on natural resources in Greenland… I’d encourage everyone to explore these “wild ideas” that come to mind—and do it with like-minded colleagues who also like to think big and a little crazy and aren’t afraid to ask the simple questions, that sometimes turn out to be not so straightforward.”

The American Geophysical Union has announced that INSTAAR postdoctoral scholar Mette Bendixen is the recipient of their 2020 Science for Solutions Award. The award follows Bendixen’s out-of-the-box work on an overlooked global challenge: the scarcity of sand resources.

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Spotlight Postdoc

Scientists predict a sea change in Arctic ecosystems by the end of the century

Mismatches in the food web

The culprit is clear

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You’ve published a ton of work during your time at INSTAAR. What is a highlight?

What are you most proud of during your time as postdoctoral scholar with INSTAAR?

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Mette Bendixen receives the AGU Science for Solutions Award

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Spotlight Postdoc

Scientists predict a sea change in Arctic ecosystems by the end of the century

Mismatches in the food web

The culprit is clear

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North Atlantic dolphins are dying younger, new study shows (CU �������� Today)

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Embracing excellence: CU �������� honors postdocs and mentors during National Postdoc Appreciation Week (Postdoctoral Affairs)

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A conversation with Jonathan Henn, 2024 CU �������� postdoc of the year

Did you always want to be an ecologist? How did you find your way to studying plant communities?

You’ve published a ton of work during your time at INSTAAR. What is a highlight?

What are you most proud of during your time as postdoctoral scholar with INSTAAR?

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Annika Horlings: Icy reflections: Fieldwork and the calling to study glaciers (USPECS)

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Chancellor's Postdoctoral Fellowship for Faculty Diversity 2024 (RIO)

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Take 5 with Michael Dyonisius

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Scientist, Olympic hopeful runs with real purpose (Colorado Arts & Sciences Magazine)

Off

A passion for science and the outdoors fuels one woman’s drive to combat climate change (Rocky Mountain PBS)

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Mette Bendixen receives the AGU Science for Solutions Award

Off

North Atlantic dolphins are dying younger, new study shows (CU �� Today)

Embracing excellence: CU �� honors postdocs and mentors during National Postdoc Appreciation Week (Postdoctoral Affairs)

A conversation with Jonathan Henn, 2024 CU �� postdoc of the year