Explore the latest insights from top science journals in the Muser Press daily roundup (July 17, 2025), featuring impactful research on climate change challenges.
In brief:
Warming oceans a turn-off for female Critically Endangered sharks
These changes are creating a potential mismatch in the mating behaviours between the sexes of angelshark that could have severe consequences for the future of the species, scientists say.
A team of marine scientists, co-led by researchers at Lancaster University and the Angel Shark Project: Canary Islands (a collaboration between Leibniz Institute for the Analysis of Biodiversity Change, the Universidad de Las Palmas de Gran Canaria and ZSL), used acoustic trackers to discover that prolonged warming of the seas around the Canary Islands is disrupting the reproductive behaviours of female angelsharks.
During a period of unusual and extreme high sea temperatures in 2022, the researchers found female angelsharks were largely absent from the species’ traditional mating grounds within the La Graciosa Marine Reserve – which is located off the coast of Lanzarote and is the largest marine reserve in Spain.
That year, sea surface temperatures in the study area rose to more than 23.8°C and remained above 22.5°C for nearly three times longer than in previous years. Crucially, these very high temperatures persisted throughout the entire angelshark mating season, which traditionally starts late autumn, when seas should be cooler.
However, while the warmer seas appeared to deter the female angelsharks, males were not put off and returned to the sites in November as normal, in search of mating opportunities.
Dr David Jacoby, Lecturer in Zoology at Lancaster University and Principal Investigator of the study, said: “These more frequent and extreme heatwaves are potentially the wildfires of the ocean and are having untold effects on marine species.
“With angelsharks we observed important sex differences in behaviour, with the females being disproportionately influenced by sea temperature rises causing them to be absent from their traditional mating sites during this extended period of warming.
“The males were much more resilient to temperature rises and stuck to their regular patterns of arrival and departure, seemingly prioritising mating despite these temperature extremes.”
The Canary Islands are at the southern extreme of angelshark distribution and the archipelago is a uniquely large stronghold for the species, which is listed as Critically Endangered by the International Union for Conservation of Nature (IUCN). Adults and juveniles are regularly sighted and are a flagship species for the local dive industry.
Between 2018 and 2023, the research team were able monitor the movement and distribution of over 100 individual angelsharks using acoustic tracking and link these data to environmental conditions.
Prior to 2022, both male and female angelsharks presence in the marine reserve consistently peaked in November and December each year.
However, in 2022 male angelshark numbers peaked as usual, but female numbers remained low all year round. The study showed that female angelshark presence is strongly linked to temperature, and that 22.5°C may be an approximate upper thermal limit for females.
During the five-year monitoring period the scientists observed a general upward trend in peak sea surface temperatures, and an increase in the number of days with temperatures above 22.5°C, from 30 days in 2019 to 85 days in 2022.
Crucially, sea surface temperatures in 2022 remained above 22.5°C into late November, only falling a month later than observed the previous year. Unusually high temperatures remained throughout the entire autumn and winter mating season.
The scientists believe that the reason female angelsharks are prioritising staying cool over mating is likely due to their biology. Female angelsharks have more energetically demanding lifestyles because of reproductive biology, and as a result are more sensitive to temperature as they need to regulate metabolic processes and energy expenditure.
Researchers are concerned that these disruptions to reproductive behaviours in angelsharks could have severe consequences for the future of the species.
“That fact that environmental extremes are driving differing male and female arrival times at coastal mating sites is of particular concern for this Critically Endangered species,” said lead author of the study Dr Lucy Mead, a researcher at ZSL’s Institute of Zoology and Lancaster University.
“Angelsharks – as with most other sharks – are ectothermic, which means their body temperature directly depends on surrounding water temperatures It seems that male angelsharks prioritise mating even when conditions are unfavourable, while females prioritise staying within their preferred temperature range.
“The Canary Islands are already at the warmer end of tolerable temperatures for angelsharks, and with significant warming projected here, our concern is that key areas may become inhospitable for females. These findings have important implications for how we conserve this highly threatened species in a warming world. Climate change impacts in the ocean tend to be ‘out of sight, out of mind’, but just as heatwaves and wildfires are becoming more frequent on land, so are extreme events in the oceans.”
Eva Meyers, co-lead of the Angel Shark Project and researcher at the Leibniz Institute for the Analysis of Biodiversity Change (LIB), said: “These findings are a reminder of how climate extremes are already reshaping the behaviour of threatened marine species. This study highlights exactly why long-term monitoring of critical habitats in the Canary Islands must be a key pillar of any effective marine biodiversity recovery plan. The Canary Islands are one of the main strongholds for this species – safeguarding these waters is more urgent than ever.”
Dr David Jiménez Alvarado, Co-Lead of the Angel Shark Project and postdoctoral researcher at the EcoAQUA Institute (University of Las Palmas de Gran Canaria), said: “It’s important to understand how changes in the ocean’s physicochemical conditions can affect the species that inhabit coastal ecosystems. These environmental shifts may alter the habitat use and behaviour of key predatory species that play a crucial role in maintaining trophic balance. Since many of these species are already globally threatened, studying how climate-related stressors impact their ecological function is essential for developing effective conservation and management strategies.”
The research is outlined in the paper ‘Rapid ocean warming drives sexually divergent habitat use in a threatened predatory marine ectotherm’ which has been published in Global Change Biology.
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The research has been supported by Shark Conservation Fund, Oceanário de Lisboa, Gobierno de Canarias, Loro Parque Fundación, Save Our Seas Foundation, Ocean Tracking Network, WWF Netherlands, Deutsche Elasmobranchier Gesellschaft, Queen Mary University of London, ZSL and the Natural Environment Research Council.
Journal Reference:
Mead, L. R., A. Piper, D. J. Alvarado et al., ‘Rapid Ocean Warming Drives Sexually Divergent Habitat Use in a Threatened Predatory Marine Ectotherm’, Global Change Biology 31, 7: e70331 (2025). DOI: 10.1111/gcb.70331
Article Source:
Press Release/Material by Lancaster University
Government rollbacks of climate monitoring is a public health emergency
In an opinion piece published in the open-access journal PLOS Climate, Jeremy Jacobs of Vanderbilt University and Shazia Khan of Yale School of Medicine draw attention to the rollback of government efforts to collect data on climate change, and how the loss of this infrastructure imperils public health efforts.
Climate disasters like heatwaves, wildfires, floods and hurricanes can contribute to a range of health conditions, including heart disease, respiratory issues, disease outbreaks, mental health crises and traumatic injuries. The elimination of federal and state tools to monitor and forecast these events makes it much more difficult for public health systems to prepare appropriately and respond, with the most vulnerable populations – children, the elderly and people with chronic conditions – suffering the greatest impacts.
In their opinion piece, Jacobs and Khan point to the recent dismantling of multiple climate monitoring efforts. The Trump administration discontinued NOAA’s Billion-Dollar Disasters Database; the EPA’s air quality monitoring, heat index surveillance and collection of climate data related to disease; and NIH funding for research into heat-related deaths, wildfire smoke exposure and how climate impacts the spread of infectious diseases. They argue that this undermining of climate data will have international effects and constitutes a public health emergency.
Jacobs and Khan call on the scientific and medical communities to defend the integrity and visibility of climate data as foundational to public health. They urge scientific journal editors and funding agencies to support research related to climate and health, to emphasize transparency and not to bow to political pressure to censor correct terminology.
“To ignore climate data is to abandon public health in the face of its greatest modern challenge,” Jacobs said. “It is to walk into the next disaster with eyes wide shut.”
Journal Reference:
Jacobs JW, Khan SS, ‘Erasing the evidence: United States climate rollbacks and the implications for public health’, PLOS Climate 4 (7): e0000667 (2025). DOI: 10.1371/journal.pclm.0000667
Article Source:
Press Release/Material by PLOS
Self-reporting climate anxiety in the United States
A new study describes factors associated with self-reported climate anxiety in the United States, publishing in the open-access journal PLOS Climate by Katherine Kricorian from For Good Measure, United States, and colleagues Karin Turner and Christopher Kricorian, who is also a current high school student.
Climate change has many adverse effects on the environment and human health, including higher rates of self-reported anxiety. In this study, Kricorian and co-authors investigated factors associated with self-reported climate anxiety.
The authors surveyed 2000 US adults demographically representative of the US population, asking about their knowledge, beliefs, behavior, and emotions related to climate change, including the question: “Does climate change make you feel anxious?”
26 percent of respondents indicated they felt anxiety around climate change. 48 percent of respondents without anxiety around climate change also denied that climate change is real. Significant predictors of self-reported climate anxiety included: greater media exposure to climate change information; more frequent discussions about climate change with friends and family; the perception that climate change will soon impact one personally; being younger; and being female.
Perhaps surprisingly, familiarity with climate change, political party, and education level were not significant predictors of climate anxiety. Climate anxiety was also associated with both positive and negative emotions, including motivation, interest, sadness, and tension, as well as greater engagement in environmental behaviors such as recycling. Respondents reporting climate anxiety were also more likely to believe volunteering for environmental causes and accessing straightforward climate information with less scientific jargon would help mitigate their climate anxiety.
The authors note that their survey respondents had previously agreed to participate in research projects more generally before being included in this study and thus may not fully represent the US population. They hope future research in this area will further explore the relationship between personal experience with climate-change-driven events, such as droughts or wildfires, and self-reported climate anxiety.
Journal Reference:
Kricorian K, Kricorian C, Turner K, ‘Predictors and correlates of self-reported climate anxiety in the United States’, PLOS Climate 4 (7): e0000534 (2025). DOI: 10.1371/journal.pclm.0000534
Article Source:
Press Release/Material by PLOS
Decline in aerosols could lead to more heatwaves in populated areas
Heatwaves are becoming more frequent around the world. And while rising temperatures caused by greenhouse gas emissions are part of the problem, the declining levels of aerosols – the small particles that make up smog and air pollution – may be driving the rise even more, particularly in populated areas.
This finding comes from a study published in Environmental Research Letters and led by researchers at The University of Texas at Austin. While recent research has linked declining aerosols to rising regional temperatures, this study is the first to examine aerosols’ impact on people’s exposure to heatwaves.
“We knew that aerosol emissions were suppressing global warming at the regional level, but the impact of that same suppression on heatwaves near urban centers was much greater than we expected,” said study co-author Cameron Cummins. “So, as cities seek to curb their aerosol emissions to improve public health, they will also likely experience more heatwaves.”
Using global climate models, the researchers found that aerosols are up to 2.5 times more influential than greenhouse gases at driving changes in heatwave occurrence in populated areas – with higher levels of aerosols suppressing heatwave exposure by reflecting the sun’s rays.
The research was led by Geeta Persad, an assistant professor at the UT Jackson School of Geosciences.
Cummins co-authored the study while earning a master’s degree from the school and first started analyzing data for the project as an undergraduate research assistant in Persad’s lab.
The researchers found that from 1920 to the present, higher aerosol levels helped suppress the occurrence of heatwaves in populated areas by about half. However, this trend is now reversing due to declining aerosol levels. The decline is due in part to clean air policies, which have been passed by countries because of the negative health and environmental effects of aerosols.
Populated areas, which release the most aerosols, are particularly at risk for accelerating heatwaves driven by aerosol decline in the near future, Persad said.
“Aerosols are really good at counteracting exposure [to heatwaves] right now, but that could rapidly change in the future,” she said. “We seem to have already crossed a tipping point where declining aerosols are accelerating heatwave exposure in a lot of places.”
If global aerosol emissions continue to decline as expected in the coming decades, heatwaves are expected to go from today’s global average of about 40 days per year to an average of about 110 days per year by 2080. The regions that are projected to be hit particularly hard by heatwaves caused by declining aerosols include Sub-Saharan Africa, South Asia, South America and Western Europe.
In this study, a heatwave is defined as three or more consecutive days during a region’s warm season that exceed a 90th percentile temperature threshold.
Aerosols are often produced at the same time as greenhouse gases, when fuel or other materials are burned. However, the two behave differently in the atmosphere. Greenhouse gases raise temperatures, distribute relatively evenly around the world, and can persist from a few years to hundreds of years. Aerosols have a cooling effect, have a more regional distribution, and are often gone in a matter of weeks.
The regional distribution of aerosols and their lack of staying power is important, Persad said. It means that when countries reduce aerosol emissions, their impacts are evident often in a matter of years. That is a good thing when it comes to health and environmental benefits associated with aerosol reduction. However, the modeling results show that it makes populated areas particularly vulnerable to heatwaves as aerosol emissions decline.
Western Europe is a notable example. During the late 20th century, aerosols almost completely counteracted greenhouse gases’ impact, keeping Western Europe from experiencing many heatwaves. However, over the next 25 years declining aerosols alone could increase heatwave frequency in parts of Western Europe by 40 days per year or more.
The study results shouldn’t be taken as a license to pollute, Persad said. High aerosol levels take a direct toll on human health by harming the heart and lungs, which can contribute to disease and lead to premature death. Instead, the study’s findings should be a signal for cities to prepare for a world with more heatwave risk.
“This work suggests that what happens with aerosols in the near future is going to be really important for what happens with heat wave hazard and exposure and risk in the near future, the next 20 to 30 years,” Persad said.
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The research was funded by the National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation (NSF). The study was also co-authored by Jane Baldwin, an assistant professor at the University of California Irvine.
Journal Reference:
Geeta G Persad, Cameron Cummins and Jane W Baldwin, ‘Anthropogenic aerosol changes disproportionately impact the evolution of global heatwave hazard and exposure’, Environmental Research Letters 20, 084023 (2025). DOI: 10.1088/1748-9326/addee0
Article Source:
Press Release/Material by University of Texas at Austin
Nitrogen may limit natural climate solutions
Forests, grasslands, and other natural areas around the world have access to about a quarter less nitrogen than previously estimated, according to a new study published in Nature. Coauthored by Sarah Batterman, an ecologist at Cary Institute of Ecosystem Studies, findings have implications for natural climate solutions, as nitrogen is essential to plant growth and thus the removal of carbon from the atmosphere.
“Outside of some tropical forests and drylands, we found that the amount of nitrogen available to plants in many natural areas has been overestimated,” said Batterman, “Our results suggest there are nitrogen constraints on the terrestrial carbon sink in a range of biomes, including prairies and temperate forests.”
The study focused on nitrogen made available to plants through biological nitrogen fixation. In this process microbes – often living symbiotically with plants – transform nitrogen gas from the air into a form that plants can use to fuel growth and development. For instance, nitrogen is a crucial component of chlorophyll, the green pigment that allows plants to convert carbon dioxide into plant growth via photosynthesis. This carbon is then stored in wood, leaves, roots, and soils.
Led by Carla Reis Ely of the Oak Ridge Institute for Science and Education, an international team of scientists quantified the global distribution and magnitude of land-based biological nitrogen fixation in both natural and agricultural biomes.
They found that previous estimates of nitrogen fixation had been skewed by sampling bias. Field measurements of nitrogen fixation were often taken in natural areas where nitrogen-fixing organisms were on average 17 times more prevalent than they are worldwide, leading to an overestimation of nitrogen availability.
Whereas much of the data was historically based in tropical forests, the new study includes biological nitrogen fixation estimates from previously underrepresented niches – including shrubs, herbs, mosses, dead wood, and more – helping to identify nitrogen hotspots and deserts.
“By building the most extensive dataset of biological nitrogen fixation rates on land, and developing a new and biologically realistic algorithm for scaling up from field measurements,” Batterman explained, “we calculated that the amount of nitrogen fixation by microbes in natural terrestrial ecosystems is approximately 25 million tons lower each year than previously estimated.”
The missing nitrogen is equivalent to about 113 fully loaded cargo container ships.
Having more accurate biological nitrogen fixation rates allows for vast improvements in the models that are used to predict how much carbon dioxide the land system takes up, and how it will be affected by climate change, Batterman added.
The analysis also revealed a rise in biological nitrogen fixation in agricultural systems that may be contributing to the degradation of land, air, and water quality. Nitrogen-fixing crops such as soybeans and alfalfa support soil health and help produce food for a growing global population, but in excess, nitrogen can be harmful. The team estimated that agricultural crops alone (not including chemical fertilizers) have increased terrestrial biological nitrogen fixation by 64% relative to pre-industrial rates.
“Excess nitrogen can leach into groundwater or runoff into lakes and streams, causing algae blooms and harming aquatic life,” said Reis Ely, who led the study while she was a postdoctoral scholar at Oregon State University.
In addition, surplus nitrogen can become nitrous oxide, a potent greenhouse gas, and high nitrogen levels can favor fast-growing invasive plants that squeeze out native species and reduce biodiversity.
The study “helps us understand the degree to which we have modified the nitrogen cycle, exceeding the safe operating space for humanity when it comes to nitrogen,” said Batterman.
Reis Ely called for more consistent measuring and monitoring of biological nitrogen fixation, “to help us ensure we have all the nitrogen in the ground that we need without it becoming too much of a good thing.”
For her leadership on the paper, Reis Ely has earned the Gene E. Likens Junior Scientist Outstanding Publication Award from the Ecological Society of America’s Biogeosciences Section. Named after Cary founder Gene Likens, who co-discovered acid rain, the award promotes early-career scientists and highlights exceptional work in the field.
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This research was supported in part by an appointment to the US Geological Survey (USGS) Research Participation Program administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Departments of Energy (DOE) and Interior (DOI) under DOE contract number DE-SC0014664. The paper is a contribution from a working group on biological nitrogen fixation supported by the USGS John Wesley Powell Center for Analysis and Synthesis.
Journal Reference:
Reis Ely, C.R., Perakis, S.S., Cleveland, C.C. et al., ‘Global terrestrial nitrogen fixation and its modification by agriculture’, Nature 643, 705–711 (2025). DOI: 10.1038/s41586-025-09201-w
Article Source:
Press Release/Material by Cary Institute of Ecosystem Studies
Featured image credit: Gerd Altmann | Pixabay
