Fossils reveal rapid land recovery after end-Permian extinction

Fossil evidence from North China suggests that some ecosystems may have recovered within just two million years of the end-Permian mass extinction, much sooner than previously thought.

eLife

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A paleo-art reconstruction of a scene from the late Early Triassic, showing a coastal mudplain to alluvial ecosystem in the Heshanggou Formation, North China

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Credit: Mr J Sun (CC BY 4.0)

Tropical riparian ecosystems – those found along rivers and wetlands – recovered much faster than expected following the end-Permian mass extinction around 252 million years ago, according to new research.

The study, published February 14 as a Reviewed Preprint in eLife, is described by the editors as an important paper on the recovery of animal and plant life on land following the end-Permian mass extinction. They say the authors provide convincing evidence for a rapid recovery in tropical riparian ecosystems after a short phase of hostile environments, based on data from sediments, animal and plant fossils, and trace fossils from North China.

The end-Permian mass extinction occurred around 252 million years ago, and wiped out over 80% of marine species and 70% of terrestrial species due to extreme environmental changes including global warming, ocean acidification and prolonged droughts.

“Recovery in marine life after the end-Permian extinction has been extensively studied, but the timeline of ecosystem recovery in life on land is much less understood,” says lead author Dr Li Tian, Associate Researcher at the State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China. “Whereas it has long been theorised that low latitudinal land regions remained uninhabitable for an extended period of time, 7–10 million years after the extinction, our results suggest that some ecosystems were more adaptable than previously thought.”

To reconstruct the timeline of ecosystem recovery on land, Tian and colleagues analysed trace fossils (such as burrows and footprints), plant remains and vertebrate fossils preserved in sedimentary rocks spanning the Early Triassic, which followed the end-Permian extinction around 252–247 million years ago. These fossils were obtained from lake and river deposits in the central North China Basin. The team used a combination of techniques such as biostratigraphy, ichnology (the study of trace fossils), sedimentology and geochemical analyses.

Their studies suggest a harsh environment at the start of the Early Triassic period, with only sparse and simple life remaining. The fossils from this period indicate a monospecific community, meaning that only a single type of organism dominated, with little evidence of biodiversity. The fossils showed a notable reduction in organism size compared to before the end-Permian extinction – a common indicator of extreme environmental stress.

However, fossils from the Spathian stage (around 249 million years ago) showed an increase in plant stems, root traces, and signs of burrowing activity, suggesting a more stable and structured environment. The team also discovered fossils of medium-sized carnivorous vertebrates, indicating that multi-level food webs had been established by this stage. The resurgence of burrowing behaviour, which had largely disappeared after the extinction event, was a key finding. Burrowing behaviour plays an important role in aerating sediment and cycling nutrients in riparian ecosystems and suggests that animals during this time adapted to environmental stresses by escaping underground.

The findings challenge the view that ecosystem recovery on land after the extinction lagged significantly behind marine life, revealing that some ecosystems were already stabilising within a relatively short geological time frame.

The researchers note that further studies are needed to determine whether similar recoveries occurred in other land regions during the Early Triassic. Further evidence would help us to understand more about how life recovered from past mass extinctions and could offer valuable lessons about ecosystem resilience and adaptation in the face of modern climate change.

“Our study is the first to suggest that, contrary to past assumptions, life in tropical-subtropical riparian ecosystems rebounded relatively quickly after the end-Permian mass extinction,” concludes senior author Jinnan Tong, Principal Investigator at the State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences. “The fossil records we studied suggest that riparian zones played a crucial role in stabilising ecosystems after the extinction. Rivers and wetlands may have acted as refuges, providing more stable conditions that allowed life to rebound more quickly than drier, inland regions.”

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eLife transforms research communication to create a future where a diverse, global community of scientists and researchers produces open and trusted results for the benefit of all. Independent, not-for-profit and supported by funders, we improve the way science is practised and shared. In support of our goal, we launched the eLife Model that ends the accept/reject decision after peer review. Instead, papers invited for review are published as Reviewed Preprints that contain public peer reviews and an eLife Assessment. We also continue to publish research that was accepted after peer review as part of our traditional process. eLife is supported by the Howard Hughes Medical Institute, Knut and Alice Wallenberg Foundation, the Max Planck Society and Wellcome. Learn more at https://elifesciences.org/about.

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Journal

eLife

DOI

10.7554/eLife.104205.1 

Article Title

Rapid riparian ecosystem recovery in low-latitudinal North China following the end-Permian mass extinction

Article Publication Date

18-Feb-2025

 

Sunscreen's potential impact on marine life needs urgent investigation

University of Plymouth

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The chemicals found in sunscreens are becoming an increasing presence in our ocean. But there are still significant gaps in our understanding of how they might affect marine ecosystems, according to a new study.

Sunscreens contain chemical compounds that filter out the sun’s ultraviolet (UV) rays. UV filters are also added to personal care products (e.g. shampoos, moisturisers, lipsticks, shower gels) and various other commercial products including plastics, rubber, paint and cement, to enhance light resistance and prevent photodegradation. 

As a result of modern lifestyles, with UV filters vital for human health and extending the lifespan of materials, they are emerging as a major environmental concern due to their widespread use and worldwide distribution.

With global sunscreen sales projected to reach $13.64 billion by 2026 and an estimated 6,000-14,000 tonnes of UV filters released annually into coral reef zones alone, researchers emphasize the urgent need for more comprehensive studies on their environmental impact.

Lead author Anneliese Hodge, PhD researcher at Plymouth Marine Laboratory and the University of Plymouth said: "This review indicates that current research has only scratched the surface of understanding how these chemicals can affect marine life. What's particularly concerning is that these compounds are considered 'pseudo-persistent pollutants' due to their continuous introduction into marine environments as well as an overall lack of understanding of how these chemicals then interact with others in the sea. That’s why it’s so important for us to be researching the effects of these compounds on marine life from all geographical regions – temperate and tropical, including the work we are conducting here at PML and the UoP on UK marine organisms. We really need to understand how these chemicals interact in the marine environment and if they have the potential to bioaccumulate within the food-chain.”

How does sunscreen get into the ocean?

UV compounds can enter the marine environment either directly or indirectly. Direct pathways include swimming or other water-based recreational activities, and indirect pathways include washing towels that have been used to dry sunscreen-coated skin, washing off residue during showering and even in urine.

Traditional sewage and water treatment technologies cannot effectively remove most UV filter compounds, and organic UV filters have been reported in 95% of wastewater effluents and 86% of surface waters globally. UV filters have also been detected in marine environments worldwide, from busy tourist locations to remote areas, such as Antarctica and the Arctic, highlighting the extent of this contamination.

Sunscreen pollution has recently been linked with agricultural practices too, whereby recycled water from wastewater treatment plants and sludge biosolids are used as soil fertilisers. This practice can result in the spread of UV filter contaminants not only onto crops, but also into agricultural run-off and discharge mechanisms that flow into aquatic environments.

Another source of UV filter contamination in the aquatic environment is through the use of beach showers. A study found that sands around the beach showers of Hanauma Bay, Hawaii were highly contaminated with sunscreen residues, level of which directly correlated with high visitation rates.

Professor Awadhesh Jha, Professor in Genetic Toxicology and Ecotoxicology at the University of Plymouth and the study’s senior author, said: “There are increasing amounts and varieties of sunscreens entering the environment, and contaminants occur in all possible combinations. It is therefore imperative that we understand their bioaccumulation potential across the food chain, and the mechanisms through which they act at molecular and cellular levels, alone and in combination with other stressors. Adopting an interdisciplinary approach will help to find the relative sensitivities of the organisms and to estimate potential environmental risks, in line with UN Sustainable Development Goals (SDG). This should also enable us to explain any potential risk to human health, as marine food constitutes an increasingly important part of our diet globally, with 4.3 billion people reliant on fish for as much as 15% of their animal protein intake. Safeguarding the production of healthy seafood in the changing environment is crucial for the sustainability of aquaculture industry too.”

Complex combinations of chemicals

The new study, published in the journal Marine Pollution Bulletin, was based on a review of more than 110 publications linked to sunscreen, UV filters and their ecotoxicological or environmental impact. It highlighted that at least 25% of sunscreen products wash off during sea bathing and a single beach with 1,000 visitors can be subject to more than 35kg of sunscreen deposits per day.

The chemicals or ingredients used in sunscreens can either be organic (chemical-based) or inorganic (mineral or metal-based) and each type can have different properties, structures and solubilities. Organic UV filters, which consist of up to 55 different compounds registered for use globally, act by absorbing incoming UV radiation. In contrast, inorganic UV filters, which are sometimes marketed as ‘reef safe’, include titanium dioxide (TiO2) and zinc oxide (ZnO) that reflect or scatter incoming radiation.

A single UV filter on its own has a limited absorption wavelength capability against UV radiation, and therefore, combinations are used to protect against the whole UV spectrum. Typically, between three to eight different UV filters are used in a single organic-based sunscreen formulation, which can make up to 15% of the overall product mass.

Benzophenones (BPs) are the most common and extensively used UV filters in sunscreens, with a total of fourteen BP derivatives being used in commercial personal care products. Benzophenones have been classified as persistent, bio-accumulative and toxic substances, and benzophenone-3 is currently on the European Chemical Agency’s watch-list as ‘under investigation as a hormone-disrupting chemical’.

Co-author Dr Frances Hopkins , PhD supervisor and Marine Biogeochemist at Plymouth Marine Laboratory, said: “This review highlights the mindboggling range of sunscreen-derived chemicals that we know are released into coastal marine environments – and demonstrates that our understanding of the effects of these toxic compounds on marine organisms is surprisingly limited. Such environments face a range of human-induced stressors, from marine heatwaves and eutrophication to longer term ocean warming and acidification, so it is vital we understand the additional impact of this pervasive chemical pollution on these already stressed ecosystems.”

A pressing need for research and action

Little research has been conducted on the specific ecotoxicological effects of these omnipresent compounds, and the long-term effects associated with their dispersal in marine environments.

Co-author Dr Mahasweta Saha, PhD supervisor and Marine Chemical Ecologist at Plymouth Marine Laboratory, said: “This work underscores the vast unknowns surrounding the impact of toxic chemicals on our already fragile marine environment. With marine ecosystems facing immense stress, we are essentially sitting on a ticking time bomb. It is crucial to exercise caution in introducing new substances, as they could exacerbate existing challenges. Thoughtful, science-driven decision-making is essential to prevent further harm.”

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Journal

Marine Pollution Bulletin

DOI

10.1016/j.marpolbul.2025.117627 

Method of Research

Literature review

Subject of Research

Not applicable

Article Title

Ecotoxicological effects of sunscreen derived organic and inorganic UV filters on marine organisms: A critical review

Article Publication Date

18-Feb-2025

 

Melting glaciers – Study shows growing lake areas, but flooding from smaller lakes

University of Potsdam

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Dr. Georg Veh in front of Lake No Lake in British Columbia (Canada), this lake is dammed by the Tulsequah glacier in the background and empties several times a year.

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Credit: University of Potsdam

For many years, scientists have been discussing whether the population in mountain regions is increasingly at risk from meltwater floods, as melting glaciers release more and more water. A small proportion of this meltwater remains in the glacial lakes around the world. If their dams break, the corresponding glacial lake floods can have catastrophic consequences for the population living downstream. The Potsdam research team was able to show that it is not only the increasing number and surface area of glacial lakes that determines the risk of such floods. By analyzing satellite images of almost 1700 documented glacial lake floods in 13 glacier regions around the world over a period from 1990 to 2023 they found that the areas of ice dammed lakes became smaller, while those of moraine-dammed lakes remained largely constant. Overall, they were unable to identify a trend towards larger lake floods.

“Some lakes have developed a wide outlet over time. This allows the rivers from these lakes to discharge the meltwater very efficiently without necessarily breaking the dam. Other lakes, especially in the Alps, Peru and Norway, have been artificially reinforced with dams in order to use them intensively for hydropower”, says leading author Dr. Georg Veh from the Institute of Environmental Science and Geography. Such lake changes contribute to the fact that floods tend to originate from smaller lakes, even if lake areas are increasing globally.

Not all lake floodings behave in the same way. Glacial lakes that are held back by glacier ice do break out more frequently due to increasingly unstable ice masses. However, the resulting flood events are on average less massive due to the smaller lake volumes. Other lakes are dammed by moraines left behind by glacial melting. In the Himalayas, Alaska and Patagonia in particular, the potential danger posed by moraine-dammed lakes for settlements and infrastructure downstream has increased as their volume continues to grow. However, catastrophic flooding by moraine-dammed lakes, such as in India in 2023 with at least 55 fatalities, remain rare.

The authors emphasize how closely climate change, glacier retreat and natural hazards are linked - and how important it is to continuously monitor these processes. “Remote sensing plays a key role here. It allows us to monitor processes in places that would otherwise be inaccessible, across a wide area and at low cost. At our institute, we use daily high-resolution satellite images to better monitor the growth of glacial lakes”, says Dr. Veh. The real-time data provides a valuable basis for risk management in mountainous regions. Therefore, future measures to protect people, roads and power plants can be better planned on site.

Link to Publication: Georg Veh, Björn G. Wang, Anika Zirzow, Christoph Schmidt, Natalie Lützow, Frederic Steppat, Guoqing Zhang, Kristin Vogel, Marten Geertsema, John J. Clague & Oliver Korup, Progressively smaller glacier lake outburst floods despite worldwide growth in lake area, Nature Water, https://doi.org/10.1038/s44221-025-00388-w

Image 1: Dr. Georg Veh in front of Lake No Lake in British Columbia (Canada), this lake is dammed by the Tulsequah glacier in the background and empties several times a year. (Image: Natalie Lützow)
Image 2: Tulsequah Lake, which is also dammed by the Tulsequah glacier. (Image: Georg Veh)
Image 3: Crillon Lake, an ice-dammed lake in the Glacier Bay National Park, Alaska, USA (Image: Georg Veh)

Tulsequah Lake, which is also dammed by the Tulsequah glacier.

Crillon Lake, an ice-dammed lake in the Glacier Bay National Park, Alaska, USA.

Credit

University of Potsdam

Journal

Nature Water

DOI

10.1038/s44221-025-00388-w 

Article Publication Date

18-Feb-2025

 U$ WHITE SUPREMACIST MEDICINE  

Racial disparities seen in care after abnormal mammograms

Despite subpopulations’ similar onsite access to diagnostics and biopsy, the use of those capabilities varied, a study shows

University of Washington School of Medicine/UW Medicine

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Despite similar availability of diagnostic technologies to women of different racial and ethnic groups, significant disparities were seen in who actually received same-day diagnostic services and biopsies after abnormal mammogram findings, new research shows.  Even when breast-care facilities had the necessary technology and capabilities, minority groups were less likely than white women to receive diagnostic imaging on the same day as an abnormal screening result. Black women in particular were less likely to receive same-day biopsies, compared with white women.

The findings of a retrospective study are to be published Feb. 18 in the journal Radiology.  The lead author is Dr. Marissa Lawson, assistant professor of radiology at the University of Washington School of Medicine. Dr. Christoph Lee, UW professor of radiology, was senior author.

“We’re looking at how the diagnostic workup process might contribute to the population disparities we see with breast-cancer outcomes,” Lawson said. “It was surprising to find similar availability (of technologies) across racial and ethnic groups. But we still saw big differences in who was getting those same-day services.”

The retrospective study spanned nearly 11 years, from January 2010 to December 2020.  The data represented more than 1.1 million female patients ages 40-89 and more than 3.5 million screening mammograms. The patients were seen in six U.S. states at 136 screening facilities that, as members of the Breast Cancer Surveillance Consortium, make data available for study.

The screening results were from individuals who self-identified as Asian (10%), Black (13%), Hispanic/Latinx (6.5%), white (68%) and “All others” (2%).

With the multilevel analysis, the researchers hoped to shed light on how factors such as race and ethnicity, household income and neighborhood educational attainment affected access to, and use of, breast-cancer diagnostics.

In the study, they first identified which consortium facilities offered onsite access to both standard-care and advanced diagnostics and biopsy. They then measured patients’ access to these capabilities, discerned which screening mammograms yielded an abnormal result, and evaluated those patients’ receipt of diagnostic imaging and biopsy on the same day and within 90 days at facilities that had the technology and capability onsite.

The researchers adjusted for several potentially influential factors such as patient breast density, biopsy history, personal and family history of breast cancer.

Asian, Black and Hispanic/Latinx patients received fewer same-day diagnostic services after undergoing a screening mammography with abnormal results at facilities offering any diagnostic or biopsy services.  Patients who lived in the lowest-income neighborhoods were 58% less likely to have same-day diagnostic evaluations than those living in the highest-income neighborhoods.

Notably, Lawson said, rural-resident patients were more likely to receive same-day diagnostic services than were urban residents.

Black patients and those who lived in a relatively lower median income were less likely than white patients to receive same-day biopsy at a capable facility. However, Hispanic/Latinx patients were more likely than white patients to receive same-day biopsy.

“Getting a screening mammogram is an anxiety-inducing experience for a lot of people, and most patients I encounter want their results as soon as possible,” Lawson said.

“If you're able to do a diagnostic workup on the same day, instead of making them wait to schedule a follow-up visit — which might create a headache with work or transportation — that’s better for the patient. And if treatment is advised based on imaging and biopsy, we should do all we can to shorten the time between screening and treatment (for those diagnosed with breast cancer).”

The authors acknowledged several limitations, including a study population that might not be nationally representative of women’s education and rural residency. Variables that might affect patients’ ability to take advantage to clinic services, such as employment, insurance status, transportation barriers and childcare needs, were not included in the analyses. It also is unknown whether individual patients declined the opportunity for same-day services or were not offered such services.

The study received funding from the National Cancer Institute (R01 CA266377, 
P01 CA154292)
 

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Journal

Radiology

DOI

10.1148/radiol.241673 

Method of Research

Literature review

Subject of Research

People

Article Title

Disparities in Standard-of-Care, Advanced, and Same-day Diagnostic Services Among Patients with Abnormal Screening Mammography

Article Publication Date

18-Feb-2025

Racial disparities seen in same-day breast diagnostic and biopsy services

Radiological Society of North America

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OAK BROOK, Ill. – Different sociodemographic groups, especially racial and ethnic minorities, are less likely to receive timely breast cancer diagnostic services after an abnormal screening mammogram, according to a study published today in Radiology, a journal of the Radiological Society of North America (RSNA).

Routine yearly screening mammography is an important first step in the early diagnosis of breast cancer. When a screening mammogram comes back as abnormal, additional imaging and image-guided biopsy may be necessary to diagnose breast cancer.

When it is caught early enough, before symptoms are present, breast cancer can be easier to treat and significantly reduces a patient’s chance of dying of cancer. A delay in diagnosis can result in further progression of the disease and a poorer overall prognosis for the patient.

Receiving diagnostic services on the same day of an abnormal screening can aid in a timely cancer diagnosis. However, not all screening facilities offer additional diagnostic or same-day services. This means a potential delay in a cancer diagnosis for many patients.

Researchers from the University of Washington sought to identify if there is a link between sociodemographic factors and access to screening facilities with adequate diagnostic services. 

“Many people are aware of the need to reduce disparities in the uptake of screening mammography. However, ensuring availability and receipt of quality diagnostic breast imaging is also necessary to diagnose breast cancer,” said study author Marissa B. Lawson, M.D., M.S., assistant professor of radiology at the University of Washington School of Medicine in Seattle. “Identifying and understanding the disparities in diagnostic breast imaging can facilitate the development of interventions that aim to close gaps in this care pathway and may ultimately improve breast cancer outcomes and patient satisfaction.”

For this retrospective study, Dr. Lawson and colleagues compiled data from six Breast Cancer Surveillance Consortium breast imaging registries.

The data included over 3.5 million screening mammograms that were conducted on 1.1 million women at a total of 136 facilities located throughout the U.S. Of the 1,123,177 women, approximately 10% were Asian, 13% were Black, 6.5% were Hispanic, 68% were white, and 2.2% were “all others.” Of the 9.3% of screenings that resulted in abnormal mammograms, 265,309 examinations were included in the analysis evaluating same-day services.

Approximately 66% of the screening facilities performed same-day diagnostic services. Although onsite availability of most diagnostic services was similar across race and ethnicity groups, the researchers found that racial and ethnic minority groups were less likely to receive standard-of-care diagnostic imaging after abnormal screening compared with white patients.

“Despite having similar availability of diagnostic breast imaging services, there were substantial differences in whether patients received some of these services by race and ethnicity and neighborhood-level socioeconomic status,” Dr. Lawson said.

Racial or ethnic minorities were less likely to have access to some diagnostic technologies within 90 days of their abnormal screening. Compared to white patients, Asian and Black patients were less likely to undergo digital breast tomosynthesis.

Additionally, patients who identified as Asian, Black or Hispanic/Latinx were less likely to receive diagnostic imaging on the same day as their abnormal mammogram. However, Hispanic patients were more likely to receive same day biopsy in comparison to white or Black patients.

Patients living in neighborhoods with a lower average income also experienced disparities in access to diagnostic services.

The researchers note that some interventions may reduce disparities in timely breast cancer diagnosis, such as legislation to require health insurance plans to provide coverage of diagnostic breast imaging without out-of-pocket costs or the establishment of patient navigation services at facilities to help patients arrange timely appointments for diagnostic imaging.

“Future studies should assess other factors that may impact whether patients receive specific diagnostic breast imaging services, such as insurance status or patient preferences,” Dr. Lawson said. “In addition, we should seek to understand how diagnostic breast imaging accessibility, timeliness and quality ultimately impact breast cancer outcomes.”

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“Disparities in Standard-of-Care, Advanced, and Same-Day Diagnostic Services among Patients with Abnormal Screening Mammography.” Collaborating with Dr. Lawson were Weiwei Zhu, M.S., Diana L. Miglioretti, Ph.D., Tracy Onega, Ph.D., Louise M. Henderson, Ph.D., Garth H. Rauscher, Ph.D., Karla Kerlikowske, M.D., Brian L. Sprague, Ph.D., Erin J. A. Bowles, M.P.H., Ellen S. O’Meara, Ph.D., Anna N. A. Tosteson, Sc.D., Roberta M. diFlorio-Alexander, M.D., M.S., Rebecca A. Hubbard, Ph.D., Janie M. Lee, M.D., M.Sc., and Christoph I. Lee, M.D., M.S.

Radiology is edited by Linda Moy, M.D., New York University, New York, N.Y., and owned and published by the Radiological Society of North America, Inc. (https://pubs.rsna.org/journal/radiology)

RSNA is an association of radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Illinois. (RSNA.org)

For patient-friendly information on breast cancer screening, visit RadiologyInfo.org.

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Journal

Radiology

Subject of Research

People

Article Title

Disparities in Standard-of-Care, Advanced, and Same-Day Diagnostic Services among Patients with Abnormal Screening Mammography

Article Publication Date

18-Feb-2025