Changing Winters Will Hit Arctic Lakes the Hardest

Trine Hay Setsaas

2025-09-05T10:32:00.0000000 2025-09-11T11:07:11.3330000

Early spring at Sandelvvatnet, in Målselv, Norway. Photo credit: Vegar Seljestokken/NINA

Led by scientists from USA, Canada and Norway, a newly published study uses models of sunlight, ice, and snow to reveal how warming winters are disrupting lake productivity.

Lake scientists have long overlooked the ice-covered season, leaving major data gaps on how winter conditions shape lake ecosystems, and on possible impacts of change.

“The ecology of ice-covered lakes is a bit of a black box for lake scientists. For a long time, we assumed that nothing interesting happened under the ice,” explains lead author Ted Ozersky, University of Minnesota Duluth.

But as climate change shortens winters, knowledge about how lakes function under the ice have become urgent. Ice thickness, snow depth, and timing of freeze and thaw all determine how much light reaches the water, and with it the potential for photosynthesis and food web activity.

Shifts in Productivity and Food Webs

The study shows that high-latitude lakes, from northern Norway to the Canadian Arctic, are far more sensitive to winter changes than lakes farther south. At 75°N, for example, more than half of the year’s solar radiation arrives while lakes are still ice-covered. Even small shifts in ice duration or transparency can therefore trigger large ecological impacts.

“In northern Norway and in other Arctic regions, many lakes are still frozen well into the midnight sun period. In these Arctic lakes, under-ice primary production can contribute substantially to food webs and could be threatened by predicted increases in snow cover. On the other hand, less ice during continuous daylight could create favorable conditions for more open-water productivity,” says co-author Amanda Poste, Norwegian Institute for Nature Research (NINA)

As warming continues, this mismatch could narrow. More overlap between light and warmth may boost biological productivity but also reshape predator–prey relationships and the timing of food web events.

A Global Effort to Understand Frozen Lakes

“Many researchers who are starting to study frozen lakes focus on just one region. By collaborating with scientists across the northern hemisphere, from Minnesota to Québec to the high Arctic, we were able to identify this large-scale pattern,” concludes Ozersky.

The findings offer a new framework for predicting how climate change will affect lakes worldwide. The authors are now working with dozens of international partners to expand winter lake monitoring in order to understand and address future trends.

Amanda Poste and Eva Leu will follow up these questions as Norwegian partners in a recently funded Nordforsk-project, led by Milla Rautio titled: Arctic freshwater food systems: Influence of warming winters and increased snow cover (FROST, running from 2025-2029).

Read the article here

Contact: Amanda Poste

Vibrant life on Antarctica’s ice caps: Scientists reveal vast communities of photosynthetic algae on the ice

Camilla Næss

2025-03-27T10:30:00.0000000 2025-03-27T10:34:47.9030000

A research team led by Dr Matthew Davey at the Scottish Association for Marine Science (SAMS) spent two months studying algal and plant communities on the Robert Island ice cap, a remote part of the northern tip of the Antarctic Peninsula. 

Microorganisms unique to Antarctica

Their survey, published in Nature Communications, found that photosynthetic algae grew across up to 20% of the ice in the area mapped - an area equal to nearly 6% of known photosynthetic-life in Antarctica.
Using microscopy and DNA analysis, the team identified a diverse array of species, including snow and glacier algae. Many of these microorganisms appear to be unique to Antarctica, highlighting the continent’s biological richness even in its harshest environments.

Algae add to the melting of the ice caps

The survey also highlighted the contribution of the algae to surface melting on the ice. Vibrant red and purple pigments, produced by the algae, act as solar absorbers, transferring heat and melting the surrounding snow and ice. Satellite imagery and ground-based measurements by the team showed that these algal blooms could contribute to as much as 2.4% of the ice cap’s surface melt on certain days.

“This is the first time these ice-cap communities in Antarctica have been mapped and studied in detail,” said Dr. Alex Thomson, the study’s lead author from SAMS. “We know that ice-free areas in Antarctica serve as oases for life, but discovering this extent and diversity of life on the ice itself was like finding forests in a desert.”

The expedition, funded by UKRI NERC and supported by the RRS Sir David Attenborough on its maiden Antarctic voyage in late 2022, included scientists and support from the University of Edinburgh, the Norwegian Institute for Nature Research, the University of Cambridge, the British Antarctic Survey, and Chile’s Instituto Antártico Chileno (INACH). 

While the study focused on a single location, researchers suspect that similar algal ecosystems may exist elsewhere on the continent’s ice sheets.

“Now that we know there are large glacial algal communities in Antarctica, the goal is to see how extensive they are, how they contribute to Antarctica’s wider biodiversity and what role they play in influencing glacial melt rates there” said Dr Andrew Gray, a researcher on the project at the Norwegian Institute for Nature Research. 

Beyond offering fresh insights into Antarctic biodiversity, the authors hope that the findings could improve climate models by refining our understanding of melting processes in the region.

Read article: Thomson, A.I., Gray, A., Colesie, C. et al. Surface darkening by abundant and diverse algae on an Antarctic ice cap. Nature Commun 16, 2647 (2025).

Contact: Andrew Gray 

Related: Antarctic-wide survey of plant life to aid conservation efforts

The Arctic Coastal Ocean is strongly affected by climate change - but overlooked in climate models

Juliet Landrø

2024-10-15T12:00:00.0000000 2024-10-22T11:19:23.0330000

Researchers have studied the effect of melting glaciers on light access for kelp in Young Sound in Greenland. Photo credit: Karl Attard.

It is well documented that the Arctic is warming 3-4 times faster than in other parts of the globe and that sea ice, glaciers and permafrost are melting at an alarming rate. However, what is happening in areas where all these changes take place at the same time?

- We are seeing major changes in the coastal areas in the Arctic, says R&D Manager Paul Renaud from Akvaplan-niva.

- Pollution, alien species and changes in the coastal resources on which local communities depend, represent a shift in the livelihoods of human societies in these areas, he says.

A team of researchers from Akvaplan-niva, Aarhus University and the Norwegian Institute for Nature Research NINA, has now published their results in Limnology and Oceanography Letters.

Here, the team concludes that focus should be on coastal areas to understand how rapidly the living conditions of plants, animals and people in the Arctic are affected by climate change. In fact, the accelerating effects of climate change can no longer be reversed, which leaves adaptation as the only alternative for communities living there.

- We see how the climate change effects on land are 'exported' to the coast where they have a combined effect with climate change effects from the ocean, says Professor of Ecoscience at Aarhus University, Mikael Sejr.

The coast must cope with the new reality

Even though most people live along the coast in the Arctic, a large part of the scientific research on climate change effects in the Arctic is focused on the open ocean where changes in the sea ice can be documented using satellite images.

- It is along the coast that people live, and these changes have direct societal effects. A greater effort should be put into understanding how the coastal communities are indeed affected by climate change, says Amanda Poste, Research Director at NINA.

The existing climate change models and satellite products have not yet been developed for coastal area conditions, but work is underway.

- We hope that the climate changes in the Arctic Coast Ocean will receive an increased focus and that we soon have tailor-made models for these areas, says Mikael Sejr.

Read the full article: Mikael K. Sejr, Amanda E. Poste, Paul E. Renaud. 2024. Multiple climatic drivers increase pace and consequences of ecosystemchange in the Arctic Coastal Ocean. Limnology and Oceanography Letters

Contact:

Amanda Poste, Research Director, NINA

Paul E. Renaud, Akvaplan-niva

Mikael K. Sejr, Professor, Aarhus University

Restored mine becomes world heritage

Juliet Landrø

2024-08-29T10:30:00.0000000 2024-09-05T12:30:56.7800000

- This proves that large nature restoration projects are important in order to safeguard and conserve our world heritage, says Dagmar Hagen, Senior Researcher at The Norwegian Institute for Nature Research, NINA.

It is the International Union of Geological Sciences (IUGS) that is now presenting "The Second 100". The first 100 geological sites of global geological importance was chosen two years ago by 700 experts from 80 countries.

Large scale nature restoration lifts our world heritage

The Svea coal mines permanently closed for operation in 2015, after 100 years of mining. At the same time landscape restoration of the mining settlement and infrastructure, stretching more than 20 km from the sea up to 700 meters above sea level, was initiated to re-establish the natural processes in the area. 

As of 2024, the restoration is complete, and to date, it is the largest nature restoration project ever carried out in Norway. Read more here.

- It is inspiring to see that the restoration has enhanced the overall quality of the area, and indeed has lifted it to world heritage status, says Hagen.

The mining company Store Norske was heading the project on behalf of the Norwegian Ministry of Trade, Industry and Fisheries. NINA contributed with our experts on nature restoration, landscape and natural processes. 

Learn more about the Svea restoration here.

Contact: 

Lars Erikstad

Dagmar Hagen

Antarctic-wide survey of plant life to aid conservation efforts

Camilla Næss

2024-08-06T11:02:00.0000000 2024-08-06T11:06:29.1170000

The satellite survey of mosses, lichens and algae across the continent will form a baseline for monitoring how Antarctica’s vegetation responds to climate change.

Scientists used a European Space Agency satellite to sweep the continent, combined with field measurements taken over several summer seasons, and detected almost 45 square kilometers of vegetation – roughly three times the size of Lake Windermere in the Lake District, UK.

The international team, led by the University of Edinburgh with the Norwegian Institute for Nature Research, British Antarctic Survey and Scottish Association for Marine Science, found that over 80 per cent of the vegetation growth was contained within the Antarctic Peninsula and neighbouring islands.

The team estimates this growth makes up only 0.12 percent of Antarctica’s total ice-free area, highlighting the importance of monitoring key areas of vegetation abundance, which is inadequately protected under the existing Antarctic Specially Protected Area (ASPA) system, experts say.

Antarctic vegetation, dominated by mosses and lichens, has adapted to survive the harsh polar conditions and each type plays an important role in carbon and nutrient cycling on a local level, experts say. Until now, their spatial coverage and abundance across the continent remained unknown.

Previous research has shown that the environmental sensitivity of Antarctica’s vegetative species makes them excellent barometers of regional climate change. Monitoring their presence in Antarctica, a minimally disturbed landscape, could provide clues as to how similar vegetation types may respond to climate in other fragile ecosystems across the globe, such as parts of the Arctic.

Charlotte Walshaw, PhD researcher from the School of GeoSciences, University of Edinburgh, who led the study, said: “Our continent-scale map provides key information on vegetation presence in areas that are rarely visited by people. This will have profound implications for our understanding of where vegetation is located across the continent, and what factors influence this distribution.”

Dr Claudia Colesie, researcher at the University of Edinburgh’s School of GeoSciences, who took part in the study, said: “Lichens and mosses in Antarctica encounter the harshest living conditions on the planet on a daily basis. Only the most resilient organisms can thrive there. Now that we know where to look for them, we can provide more targeted conservation measures to safeguard their future.”

Dr Andrew Gray, researcher at the Norwegian Institute for Nature Research, who jointly led the study, said: “Remote sensing approaches such as this are low impact methods to study Antarctica’s fragile ecosystem as well as monitor change to its vegetation in the future.”

The research, published in Nature Geoscience, was funded by the Natural Environment Research Council (NERC) and UK Space Agency. Field campaigns were supported by the British Antarctic Survey, Instituto Antarctic Chileno and Antarctica New Zealand.

For further information, please contact:

Andrew Gray, researcher at NINA

Rhona Crawford, Press and PR Office, 07876 391498, rhona.crawford@ed.ac.uk

Seabirds reveal mercury distribution across the North Atlantic

Trine Hay Setsaas

2024-05-31T10:43:00.0000000 2024-05-31T10:44:39.1130000

Map showing mercury concentrations with highest values in dark blue and lowest in yellow. Figure: NINA

Mercury (Hg) is a toxic substance that accumulates in the food chain and causes detrimental effects on wildlife and human health. The spatial distribution of this toxicant, however, is not well known, especially in food webs and at larger scales in the marine environment.

Seabirds as indicators

In a groundbreaking study recently published, a group of researchers use seabirds to assess the spatial distribution of mercury in the North Atlantic food web. The high resolution, and population and geographic magnitude of the study is unprecedented, says NINA researcher and head author, Céline Albert.

Tracking data from 837 seabirds from seven different species and 27 breeding colonies combined with feather analyses revealed the presence of mercury through the North Atlantic Arctic.

Mercury increasing from east to west

The maps show an east-west gradient in mercury concentrations, increasing from the Barents Sea in the east to the East coast of Canada in the west. Along the mercury concentration gradient, we see hot spots around southern Greenland and the East coast of Canada and a cold spot in the Barents and Kara Seas, says Albert.

The study indicates that the observed gradients could be influenced by ocean currents and melting of the Greenland Ice Sheet.

Of great importance for Arctic communities

This study is considered of great importance for Arctic communities who rely on the marine environment for their livelihoods.

Indeed, Arctic Indigenous Peoples, and especially the Greenlandic and Canadian Inuit communities, possess some of the highest concentrations of mercury in the world, with several documented negative health effects.    

With this background, the group of researchers behind this study urge the international community, including under the Minamata Convention on Mercury, to take new and rapid action to address mercury contamination of the environment and the subsequent risk to human health.  

Our work demonstrates how wildlife can be used as cost-efficient bioindicators to gather important information on mercury distribution at a large scale, essential to enable decision-makers to take necessary action, concludes Albert.

Read the article published in PNAS here

Contact:

Céline Albert

Børge Moe

Understanding climate warming impacts on carbon release from the tundra

Camilla Næss

2024-04-17T17:07:00.0000000 2024-04-17T17:16:30.5030000

A team of over 70 scientists used open-top chambers (OTCs) to experimentally simulate the effects of warming on 28 tundra sites around the world. OTCs basically serve as mini-greenhouses, blocking wind and trapping heat to create local warming.

The warming experiments led to a 1.4°C increase in air temperature and a 0.4°C increase in soil temperature, along with a 1.6% drop in soil moisture. These changes boosted ecosystem respiration by 30% during the growing season, causing more carbon to be released because of increased metabolic activity in soil and plants. The changes persisted for at least 25 years after the start of the experimental warming – which earlier studies hadn’t revealed.

"We knew from earlier studies that we were likely to find an increase in respiration with warming, but we found a remarkable increase – nearly four times greater than previously estimated, though it varied with time and location," says Sybryn Maes of Umeå University, the study’s lead author.

Some regions will see more carbon release than others

The increase in ecosystem respiration also varied with local soil conditions, such as nitrogen and pH levels. This means that differences in soil conditions and other factors lead to geographic differences in the response – some regions will see more carbon release than others. Understanding the links between soil conditions and respiration in response to warming is important for creating better climate models. 

"Our work represents the first assessment of ecosystem respiration response to experimental warming across such a broad environmental gradient in the tundra, incorporating a comprehensive set of environmental drivers," says Associate Professor Ellen Dorrepaal of Umeå University. 

The study also offers a broader perspective on Arctic and alpine regions by predicting increases in respiration across the whole tundra area together with more detailed information about variation in the sensitivity of the response.

Norwegian-Russian cooperation aims to stop the spread of alien species to the Arctic

Jan Arne Stokmo

2021-04-20T13:10:00.0000000 2021-06-30T14:51:09.3600000

The main message for travelers to Arctic regions is that they should brush, hoover and wash clothes, shoes, luggage and equipment before they start their journey. Fishing equipment should be disinfected. Such simple measures will protect the vulnerable plant and wildlife in arctic regions.

The campaign is launched this year in northwest Russia after being tested on travelers to Svalbard in a pilot project in 2018-2019. It is also now expanding to Iceland and Greenland.

Serious threat to species

"Alien species are a threat to biodiversity globally, but also in the Arctic. Our goal is to inform travelers that they can easily help reduce this problem. Seeds can get stuck on mountain shoes, parasites can follow fishing gear and so on. With simple measures, the dispersion of such stowaways can be avoided, explains Jørn Thomassen, head of the project in the Norwegian Institute for Nature Research (NINA).

NINA is leading the campaign in cooperation with the Ministry of Agriculture and Forestry in Finland and the Swedish Environmental Protection Agency in Sweden. For the launch in Russia, The National Park Russian Arctic (NPRA) is the central partner.

Will raise awareness of travelers

Alien species are species that have come to an area where they naturally do not belong, due to human activity. They are one of the biggest threats to biodiversity globally. Many people are unaware that they can unconsciously carry alien species to the vulnerable natural areas. This is what the campaign is going to do something with.

"Alien species can establish themselves and displace local species, and also threaten entire ecosystems. Climate change increases the chance of unwanted species gaining a foothold in the Arctic, Thomassen warns.

Collaboration with the tourism industry

In order for the campaign to succeed, we depend on good cooperation with tour operators, airlines, governments and more. The pilot project in Svalbard showed that the industries themselves took responsibility and were a crucial piece in reaching out to the travelers.

In Russia, the authorities and Russian tour operators carrying guests and workers to Arctic parts of Russia are also involved.

Uses animation film

An important part of the campaign consists of a two-minute animation film in which a speaking polar bear examines various travelers for alien species.

The film and accompanying website is translated into Russian and is meant to convince Russian-speaking travelers to take steps to stop the spread of alien species. The film is also subtitled in 13 languages for use in other parts of the Arctic.

Joint efforts

The campaign in northwest Russia is funded by the Ministry of Climate and Environment in Norway through the environmental cooperation programme with Russia.

For more information on the problem of alien species in the Arctic and measures to stop the spread of them on www.stoparcticaliens.com.

On behalf of the Norwegian Environment Agency, NINA has produced a report showing the status of mapping and monitoring of foreign species in the Arctic and recommended measures for further mapping and monitoring. The report from NINA (in Norwegian) can be read here.

Contacts:

NINA: Jørn Thomassen

NINA: Inga Elise Bruteig

NINA: Kristine Bakke Westergaard

Ministry of Agriculture and Forestry (Finland): Johanna Niemivuo-Lahti 

Swedish Environmental Protection Agency: Melanie Josefsson 

National Park Russian Arctic: Ivan Mizin

More about invasive species: Aliens in the Arctic (podcast)

Facts:

• Alien species are a global threat to biodiversity.
• Plant and wildlife in the Arctic is particularly vulnerable to intruders from outside.
• Travelers to arctic regions can carry seeds, insects and parasites on clothes, equipment and luggage to the Arctic without knowing it.
• The Norwegian Institute for Nature Research, the Swedish Environmental Protection Agency and the Ministry of Agriculture and Forestry in Finland have therefore made a film to raise awareness of the problem.
• The information campaign and film will now also be spread in northwest Russia.
• The main message is that you can help protect the vulnerable nature of the Arctic by taking some simple measures.
• The main measures are brushing, hovering and washing clothes, shoes, luggage and equipment before departure. Fishing equipment should be disinfected.
• The film is produced by the Trondheim-based company Klipp og lim, and is funded by the Nordic Council of Ministers, the Norwegian Environment Agency and the Governor of Svalbard.