New study reveals larger insects' critical role in decomposition in arid ecosystems

The Hebrew University of Jerusalem

 

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An isopod, well-adapted to the harsh conditions of arid-lands, crawls on the desert floor in search of plant litter. 

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Credit: Viraj R Torsekar

New study reveals that in arid ecosystems, larger arthropods such as termites and beetles play a crucial role in decomposition, challenging the traditional view that microbial activity dominates this process in dry environments. By demonstrating that macro-decomposition can peak during the summer in arid sites and that overall decomposition rates in these regions can be similar to or even exceed those in wetter climates, the research provides new insights into how decomposition functions in drylands and its implications for global carbon cycling and ecosystem management.

Link to pictures: https://drive.google.com/drive/folders/19a7FbAw4DvYeg5_GdvFJzc6p-0gMuBqp?usp=sharing

Researchers from The Hebrew University of Jerusalem have discovered a potential solution to the long-standing "desert decomposition conundrum" in a new study in eLife. Led by Dr. Viraj Torsekar, Dr. Nevo Sagi and Professor Dror Hawlena from Hebrew University, the study challenges conventional beliefs about decomposition processes across different climate gradients. Traditionally, it was thought that decomposition rates were primarily driven by microorganisms and would decrease in drier environments. However, this new research uncovers that larger arthropods play a crucial and previously underappreciated role in arid ecosystems.

Key Findings:

• Decomposers of different sizes respond distinctively to precipitation levels.
• Microbial decomposition increases with precipitation during winter months.
• Macro-decomposition, driven by larger arthropods such as termites and beetles, peaks in arid sites during the summer.
• These contrasting responses result in similar overall decomposition rates across most of the precipitation gradient.

The researchers conducted their study across seven sites in Israel, ranging from hyper-arid to Mediterranean climates. They utilized innovative litter baskets with varying mesh sizes to isolate the effects of different-sized decomposers.

"Our findings show that the contrasting climate dependencies of micro- and macro-fauna decomposers lead to unexpectedly high decomposition rates in arid environments," says Dr. Torsekar. "This provides a plausible explanation for why plant litter decomposition in drylands occurs faster than previously thought—a puzzle that has challenged scientists for decades."

"This research highlights the overlooked role of larger arthropods in dry ecosystems," adds Dr. Sagi. "By revealing that arid regions can support decomposition rates similar to or higher than wetter areas, we hope to inspire new strategies for conserving these vulnerable ecosystems."

Professor Hawlena concludes, "Understanding the dynamics of decomposition in drylands is essential for conserving and restoring critical ecosystem processes, particularly as these regions expand globally. Our findings also have significant implications for global carbon cycling and climate change models."

The study's implications reach beyond ecology, potentially influencing climate change models and conservation strategies for arid ecosystems worldwide.

A millipede foraging for plant litter in a semiarid landscape. 

  

Beetles account for most biomass of macrodecomposers across most landscapes and play a crucial role in plant litter decomposition.

Credit

Nevo Sagi

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Journal

eLife

DOI

10.7554/eLife.93656.3 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Contrasting responses to aridity by different-sized decomposers cause similar decomposition rates across a precipitation gradient

 

Abundant urban green space linked to lower rates of heat related illness and death

And better mental health and wellbeing; may offset adverse effects of high temperatures

BMJ Group

Abundant green space in urban areas is linked to lower rates of heat related illness and death as well as better mental health and wellbeing, finds a systematic review of the available research, published in the open access journal BMJ Open.

Green space may help offset the adverse health effects of high temperatures, conclude the researchers.

In recognition of the detrimental heat related effects of increasing urbanisation and climate change, one of the UN Sustainable Development Goal targets stipulates the provision of universal access to safe and accessible green and public spaces, especially for vulnerable groups, such as children, the elderly, and those living with long term conditions, by 2030.

Despite an extensive body of research on the overall beneficial effects of green spaces, their effects on heat related health risks remain poorly understood, say the researchers. In a bid to plug this knowledge gap, they looked at the effects of green zones on death and ill health in urban areas across the globe, drawing on relevant published research.

They included content published in English between January 2000 and December 2022, and reviewed 12 studies out of an initial haul of more than 3000 from Hong Kong, Australia (4), Vietnam, the USA (3), South Korea, Portugal and Japan. 

These included epidemiological, modelling, and simulation studies, as well as experimental research and quantitative analyses.

The review showed that urban green spaces, such as parks and trees, can potentially help offset the adverse health effects of high temperatures.

Areas with more green space have lower rates of heat related ill health and death than areas with less green space, particularly among vulnerable groups.

And urban greenery is associated with better mental health and wellbeing, which could also help mitigate the negative health effects of high temperatures.

The researchers point out that the differing methodology and design of the included studies precluded pooling the results for further data analysis, and while the review found associations between urban green spaces and health outcomes, it cannot establish causal relationships.

“It is important to note that more research is needed to fully understand the extent of the impact of urban greenery on heat-related morbidity and mortality, and how it interacts with other factors such as air pollution, socioeconomic status among others,” they highlight.

But they nevertheless conclude: “Urban green spaces play a vital role in mitigating heat-related health risks, offering a potential strategy for urban planning to address climate change and enhance public health.”

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Journal

BMJ Open

DOI

10.1136/bmjopen-2023-081632 

Method of Research

Systematic review

Subject of Research

People

Article Title

Health impact of urban green spaces: a systematic review of heat-related morbidity and mortality

Article Publication Date

22-Oct-2024

Ethical framework aims to counter risks of geoengineering research

Pressure for climate intervention may gain momentum as world heats up

Reports and Proceedings

American Geophysical Union

WASHINGTON — As interest grows in geoengineering as a strategy for tackling global warming, the world’s largest association of Earth and space scientists today launched an ethical framework as a guide to responsible decision-making and inclusive dialogue.  

The report, facilitated by the American Geophysical Union (AGU) and advised by a global panel of experts, says any research into large-scale interventions in Earth’s climate system must be grounded in sound ethical principles so society can make informed choices about whether to deploy them. It warns that the unintended consequences of large-scale deployment are largely unknown.  

“Climate change requires immediate action, and our most urgent, non-negotiable priority must be to tackle the root cause, carbon emissions,” said AGU President Lisa J. Graumlich. “But as pressure grows to supplement emissions reductions with active, large-scale intervention in Earth’s climate system, we must ensure that research is done in ways that are inclusive, representative and just, carefully considering risks and benefits.”  

“We all live on this one planet, but solutions cannot be one size fits all,” said Carlos Nobre, a senior researcher at the Institute for Advanced Studies in São Paulo, Brazil, and member of the Ethical Framework Advisory Board. “Global communities have unique challenges and vulnerabilities. When we contemplate how to address the existential threat of climate change, it is imperative that we do so by centering ethics. This framework helps lay the foundation for effective collaboration and partnership.” 

The report, Ethical Framework Principles for Climate Intervention Research, seeks to establish a set of globally recognized ethical principles to guide research, funding and policy proposals, drawing on precedents developed to guide research around other emerging fields with unknown consequences, including ethical practices for biomedical research and genetic engineering.

In the 2015 UN Paris Agreement, the world’s nations pledged to pursue efforts to limit global temperature rise to 1.5 degrees Celsius. However, global emissions are still increasing, and every additional fraction of a degree will see more severe storms, floods, heatwaves and other climate impacts and increase the risk of triggering catastrophic tipping points such as the Amazon rainforest transforming into dry savannah or the collapse of the Greenland Ice Sheet.

Climate interventions, also known as geo-engineering or climate engineering, are deliberate, large-scale attempts to alter the climate system in a way that halts, slows down or reverses global warming. Climate intervention technologies and methods include:  

• carbon dioxide removal, which aims to remove greenhouse gases from the atmosphere and store them, using approaches such as reforestation or increasing the ocean’s capacity to absorb carbon; 

• solar radiation modification, which aims to reduce the amount of solar radiation absorbed by Earth, such as approaches that increase the amount of sunlight reflected from clouds or space sunshades; 

• and emerging technologies and research, including those aiming to preserve ice sheets and restore sea ice and permafrost. 

“Climate intervention must not replace greenhouse gas emissions reduction,” said AGU Interim Executive Director and CEO Janice R. Lachance. “Yet there is robust discussion and debate on whether it should become part of a comprehensive strategy to slow warming, address legacy carbon emitted over the last century and get us back on track with global temperature targets. It is AGU’s privilege and responsibility as a leader in climate science to advocate for responsible pursuit of knowledge.” 

The framework has been developed over a two-year period, under the guidance of an advisory board of more than 40 international experts from a wide range of disciplines, with extensive public consultation worldwide. It reflects contributions from hundreds of scientists, policymakers, ethicists, government agencies, non-governmental organizations, the private sector and communities that could be disproportionately affected by climate change interventions. It proposes that all new research plans, funding decisions and policy proposals should meet five key principles: 

1. Responsible Research. Climate intervention research should not be presented as an alternative to emissions reductions. Researchers should provide a clear, public justification of their activity. They should not only assess its direct risks but also the physical, environmental and social consequences if it were scaled. 

2. Holistic Climate Justice. Before starting an activity, researchers should consider whether it would shift climate impacts from one group to another, as well as consider its impact on groups experiencing social, economic, climate and environmental injustices, on future generations, and on nature and biodiversity.  

3. Inclusive Public Participation. Researchers should have fair and inclusive processes to identify groups that may be impacted by the activity and include them in discussion of the purposes and design of the research. They should secure the free, prior and informed consent of any Indigenous Peoples likely to be affected. 

4. Transparency. Public and private funding of climate intervention research and experimentation should be completely transparent. Researchers should handle data responsibly, report on the nature of the science involved and document the decision-making process from start to finish. They should clearly report any negative results. 

5. Informed Governance. Where technologies have significant risks, funders should require research proposals to be reviewed and approved by an independent body. Activities with higher risks or at larger scales should have greater scrutiny. Researchers should be accountable to a representative set of public institutions and stakeholders at scales relevant to the impact of the research. 

“Communities need to be heard on decisions that affect them,” said project lead Billy Williams, AGU’s Executive Vice President, Diversity, Equity and Inclusion. “Though climate change is a risk shared by all Earth’s people, the weight of climate consequences is not carried equally. As we consider technology to counteract warming, it is essential that we do not add to that unequal burden.” 

The framework applies to all types of climate intervention and covers lab research and computer modeling as well as activities undertaken in the field. It is designed to be flexible enough to be adapted to the needs of diverse contexts and actors and capable of evolving as society’s understanding of climate risks and climate intervention technologies develops.  

AGU intends for the framework to drive discussion within the broader community involved in and affected by climate intervention research, policy and investment and prompt the development of norms for ethical and responsible research practices. 

“AGU and the contributors of this work strongly encourage all relevant actors, including researchers, funders and policymakers, to embrace these ethical principles when considering or undertaking activities relating to climate intervention research,” says the report. 

***** 

AGU (www.agu.org) is a global community supporting more than half a million advocates and professionals in Earth and space sciences. Through broad and inclusive partnerships, AGU aims to advance discovery and solution science that accelerate knowledge and create solutions that are ethical, unbiased and respectful of communities and their values. Our programs include serving as a scholarly publisher, convening virtual and in-person events and providing career support. We live our values in everything we do, such as our net zero energy renovated building in Washington, D.C. and our Ethics and Equity Center, which fosters a diverse and inclusive geoscience community to ensure responsible conduct.  

***** 

Notes for Journalists: 

The Ethical Framework Principles for Climate Intervention Research will be published on the American Geophysical Union website at 7:01 p.m. EDT (UTC-4 hours) on 22 October 2024.  Please contact Josh Weinberg for any interview requests.

Report Title: “Ethical Framework Principles for Climate Intervention Research”

AGU Project Lead: 

• Billy Williams, Executive Vice President, Diversity, Equity & Inclusion 

Contributors: 

• Tyler Felgenhauer, Duke University, Durham, N.C. 

• Matthias Honegger, Perspectives Climate Research, Freiburg, Germany 

• Ben Kravitz, Indiana University, Bloomington 

• Jane Long, Environmental Defense Fund, Washington, D.C. 

• Sean Low, Aarhus University, Aarhus, Denmark 

• Duncan McLaren, University of California, Los Angeles School of Law 

• Ilona Mettiäinen, University of Lapland, Rovaniemi, Finland 

• Ina Möller, Wageningen University, Wageningen, Netherlands 

• Shuchi Talati, The Alliance for Just Deliberation on Solar Geoengineering, Washington, D.C. 

• Daniele Visioni, Cornell University, Ithaca, N.Y. 

• Byron Williston, Wilfrid Laurier University, Waterloo, Ont., Canada 

 

Advisory Board: 

• Babatunde Abiodum, University of Cape Town, Cape Town, South Africa 

• Brad Ack, Ocean Visions, Washington, D.C. 

• Mashael Alshalan, Aeon Strategy, Riyadh, Saudi Arabia 

• Vinya Ariyaratne, Sarvodaya Shramadana Movement, Sri Lanka 

• Paul Artaxo, University of São Paulo, São Paulo, Brazil 

• Araya Asfaw, Addis Ababa University, Addis Ababa, Ethiopia 

• Govindasamy Bala, Indian Institute of Science, Bengaluru, India 

• Miranda Boettcher, German Institute for International and Security Affairs, Berlin 

• Clara Botto, The Alliance for Just Deliberation on Solar Geoengineering, Bonn, Germany  

• Antonio Busalacchi, University Corporation for Atmospheric Research, Boulder, Colo. 

• Ines Camilloni, University of Buenos Aires, Buenos Aires, Argentina 

• Michael Conathan, Ocean Policy Consultant, Portland, Maine 

• Chris Field, Stanford University, Palo Alto, Calif. 

• Karen Florini, Climate Central, Washington, D.C. 

• Stephen Gardiner, University of Washington, Seattle 

• Stephen Hammer, New York Climate Exchange, New York 

• Bruce Hewiston, University of Cape Town, Cape Town, South Africa 

• Elisabeth Holland, University of the South Pacific, Suva, Fiji 

• Marion Hourdequin, Colorado College, Colorado Springs 

• Anne-Maria Hubert, University of Calgary, Calgary, Alta., Canada 

• Peter Irvine, University College London, London 

• Penehuro Fatu Lefale, LeA International Consultants, Wellington, New Zealand 

• Margaret Leinen, Scripps Institution of Oceanography, University of California, San Diego  

• Amparo Martinez, National Autonomous University of Mexico, Mexico City 

• Taylor McKie, Scripps Institution of Oceanography, University of California, San Diego  

• Craig McLean, National Oceanic and Atmospheric Administration (Retired), Washington, D.C.  

• Axel Michaelowa, University of Zurich, Zurich, Switzerland 

• Aasima Kamal Mowni, SRM Youth Watch, Dhaka, Bangladesh 

• Helene Muri, Norwegian University of Science and Technology, Trondheim, Norway 

• Carlos Nobre, Institute for Advanced Studies, São Paulo, Brazil 

• Daniel O’Connor, Wellcome Trust, London 

• Franklin Opijah, University of Nairobi, Nairobi, Kenya 

• Silvia Peppoloni, Italian Institute of Geophysics and Volcanology, Rome 

• Christopher Preston, University of Montana, Missoula 

• Akossiwa Quashie, University of Lomé, Lomé, Togo 

• Alan Robock, Rutgers University, New Brunswick, N.J. 

• Dominic Roser, University of Fribourg, Fribourg, Switzerland 

• Vladimir Ryabinin, Intergovernmental Oceanographic Commission of UNESCO (Retired), Paris Peter Schlosser, Arizona State University, Tempe 

• Benjamin Sovacool, Boston University, Boston 

• Ben Stanhouse-James, Official Youth Constituency of the UNFCCC (YOUNGO)  

• Pablo Suarez, Red Cross Red Crescent Climate Centre, Boston 

• Masa Sugiyama, University of Tokyo, Tokyo 

• Jianhua Xu, The Institute for Global Health and Development at Peking University, Beijing 

###   

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Method of Research

Systematic review

Subject of Research

Not applicable

Article Title

Ethical Framework Principles for Climate Intervention Research

Article Publication Date

22-Oct-2024

Disclaimer: A

 

Gardens prevent pollinators from starving when farmland nectar is scarce, new study finds

University of Bristol

 

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Bombus Pascuorum

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Credit: Tom Timberlake

Gardens offer a steady and reliable source of nectar all year round, helping to keep pollinators fed when farmland sources are limited, researchers have discovered.

This consistency means that even small patches of gardens in rural areas can sustain pollinators, particularly in early spring and late summer when nectar is scarce.

In the findings, published today in Proceedings of the Royal Society B, scientists at the University of Bristol discovered that gardens can provide between 50% and 95% of the total nectar during these critical times.

Lead author Dr Thomas Timberlake based in Bristol’s School of Biological Sciences explained: “It’s well known that gardens and urban areas can be great places for pollinators like bees, flies and butterflies. In fact, past research shows that cities often have more types and numbers of pollinators than farming areas.

“There’s also evidence that pollinator populations are healthier in rural areas when they’re close to small towns or villages so we know gardens are good for pollinators, but we don’t fully understand why.

“Our study aimed to figure out exactly what it is about gardens that makes them so beneficial for pollinators.”

The team looked at how much nectar, an essential food for pollinators, is available in gardens and farmland throughout the year. While gardens only provide a relatively small amount of nectar in rural areas (less than 15%), the stability and continuity of this nectar supply makes it much more valuable to pollinators. In contrast, farmland [TT1] nectar almost disappears during certain months potentially leaving pollinators struggling.

More than 90% of farmland in Great Britain is within one kilometre of a garden. This means that the flowers in people’s gardens are accessible to many insects living in farmland areas nearby. If gardens are managed in a pollinator-friendly way, their positive impact can extend far beyond the garden fence, helping pollinators all across the country.

Dr Timberlake continued: “Many people feel powerless when it comes to fighting biodiversity loss, thinking it’s too big of a problem to tackle on their own. But our study shows that individual citizens can make a big difference.

“People can support pollinators in their gardens and surrounding farmland by simply making sure their garden has pollinator-friendly flowers blooming throughout the year—especially in early spring and late summer, when pollinators are hungriest.”

Now the team plan to find out which specific plants are best at filling those seasonal hunger gaps and whether gardens should be included in future environmental stewardship schemes. If gardens are proven to benefit pollinators more than some farmland habitats, then the creation of more pollinator-friendly gardens in rural areas could help us tackle pollinator declines.

Dr Timberlake concluded: "In a country like the UK, where towns and villages are spread throughout the countryside, gardens might be helping pollinators more than we ever realised.

“For the 27 million gardeners in the UK, this study highlights just how important their gardens can be in helping to reverse the decline of pollinators."

 

Paper:

‘Gardens reduce seasonal hunger gaps for farmland pollinators’ by TP Timberlake, NE New and J Memmott in Proceedings of the Royal Society B.

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These two bits of the sentence didn’t quite connect before, so I’ve just spelt out why it is that gardens can be so important even if they only provide a relatively small proportion of total nectar.

Bombus Terrestris

Early spring garden flowers

Credit

Tom Timberlake

Journal

Proceedings of the Royal Society B Biological Sciences

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Gardens reduce seasonal hunger gaps for farmland pollinators

Article Publication Date

22-Oct-2024

 

Paws of polar bears sustaining ice-related injuries in a warming Arctic

Peer-Reviewed Publication

University of Washington

 

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Three adult polar bears travel across sea ice in eastern Greenland. Environments in the Far North that would have stayed well below freezing now experience freeze-thaw cycles and wet snow due to a warming climate.

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Credit: Kristin Laidre/University of Washington

Polar bears in some parts of the high Arctic are developing ice buildup and related injuries to their feet, apparently due to changing sea ice conditions in a warming Arctic. While surveying the health of two polar bear populations, researchers found lacerations, hair loss, ice buildup and skin ulcerations primarily affecting the feet of adult bears as well as other parts of the body. Two bears had ice blocks up to 1 foot (30 centimeters) in diameter stuck to their foot pads, which caused deep, bleeding cuts and made it difficult for them to walk.

The study led by the University of Washington was published Oct. 22 in the journal Ecology. It’s the first time that such injuries have been documented in polar bears.

The researchers suggest several mechanisms for how the shift from a climate that used to remain well below freezing to one with freeze–thaw cycles could be causing ice buildup and injuries.

“In addition to the anticipated responses to climate change for polar bears, there are going to be other, unexpected responses,” said lead author Kristin Laidre, a senior principal scientist at the UW Applied Physics Laboratory and a professor in the UW School of Aquatic and Fishery sciences. “As strange as it sounds, with climate warming there are more frequent freeze-thaw cycles with more wet snow, and this leads to ice buildup on polar bears’ paws.”

Between 2012 and 2022, Laidre and co-author Stephen Atkinson, a wildlife veterinarian, studied two populations of polar bears living above 70 degrees north latitude and saw the injuries.

In the Kane Basin population, located between Canada and Greenland, 31 of 61 polar bears showed evidence of icing-related injuries, such as hairless patches, cuts or scarring.

In the second population in East Greenland, 15 of 124 polar bears had similar injuries. Two Greenland bears at separate locations in 2022 had massive ice balls stuck to their feet.

“I'd never seen that before,” Laidre said. “The two most affected bears couldn't run — they couldn't even walk very easily. When immobilizing them for research, we very carefully removed the ice balls. The chunks of ice weren't just caught up in the hair. They were sealed to the skin, and when you palpated the feet it was apparent that the bears were in pain.”

Researchers have studied these two polar bear populations since the 1990s but haven’t reported these types of injuries before. Consultations with lifetime Indigenous subsistence hunters and a survey of the scientific literature suggests this is a recent phenomenon.

Polar bears have small bumps on their foot pads that help provide traction on slippery surfaces. These bumps, which are larger than those on the pads of other bear species like brown and black bears, make it easier for wet snow to freeze to the paws and accumulate. This problem also affects sled dogs in the North.

The authors hypothesize three possible reasons for increasing ice buildup on polar bears’ paws — all related to climate warming. One is more rain-on-snow events, which creates moist, slushy snow that clumps onto paws and then freezes to form a solid once temperatures drop.

A second possibility is that more warm spells are causing the surface snow to melt and then refreeze into a hard crust. The heavy polar bears break through this ice crust, cutting their paws on its sharp edges.

The final possible reason is that both these populations live on “fast ice” connected to the land, near where freshwater glaciers meet the ocean. Warming in these environments leads to thinner sea ice, allowing seawater to seep up into the snow. This wet snow can clump onto bears’ feet and then refreeze to form ice. Also, unlike other areas, polar bears living at glaciers’ edges rarely swim long distances in spring, which would help thaw and dislodge accumulated ice chunks because the water is warmer than the air.

While the bears are clearly affected by the ice buildup, the researchers are cautious regarding broader conclusions about the health of the two populations.

“We’ve seen these icing-related injuries on individual polar bears,” Laidre said. “But I would hesitate to jump to conclusions about how this might affect them at a population level. We really don’t know.”

Melinda Webster, a research scientist at UW’s Applied Physics Laboratory, recently published a separate study analyzing snow cover on Arctic sea ice over recent decades.

“The surface of Arctic sea ice is transforming with climate change,” Webster said. “The sea ice has less snow in late spring and summer, and the snow that does exist is experiencing earlier, episodic melt and more frequent rain. All these things can create challenging surface conditions for polar bears to travel on.”

Asked what can be done to help the polar bears, Laidre had a simple response: “We can reduce greenhouse gas emissions and try to limit climate warming.”

The field observations of polar bears were funded by the governments of Canada, Denmark, Nunavut and Greenland. Laidre is also affiliated with the Greenland Institute of Natural Resources

This photo shows the rear paws of a polar bear temporarily sedated for research in East Greenland in 2022. The bear has large chunks of ice frozen onto its feet, which the researchers removed. It is one of two polar bears showing this type of buildup, which appears to be a new phenomenon affecting some polar bears in the Far North.

Credit

Kristin Laidre/University of Washington

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Journal

Ecology

DOI

10.1002/ecy.4435 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Icing-related injuries in polar bears (Ursus maritimus) at high latitudes

Article Publication Date

22-Oct-2024