Researchers refine the clock of Earth’s early complex animal life

University of Lausanne

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The researchers focused on exceptionally well-preserved sedimentary rocks deposited on ancient seafloors in what is now southern Sweden.

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Credit: Unil

How can we measure time more than 500 million years into the past? A study recently published in Nature Communications by researchers at the University of Lausanne presents a new geological “rock clock” that allows major climate events from the dawn of complex animal life to be dated with unprecedented precision.

The Cambrian Period (approximately 539 to 487 million years ago) represents a pivotal chapter in Earth’s history, marked by the rapid diversification of complex animal life in the oceans. Understanding this evolutionary turning point requires precise constraints on the timing of environmental changes that shaped early ecosystems. Until now, however, dating such ancient events remain challenging, as many sedimentary archives lack direct age markers.

To overcome this limitation, the researchers focused on exceptionally well-preserved sedimentary rocks deposited on ancient seafloors in what is now southern Sweden. These rocks accumulated continuously over millions of years and retain both fossil remains and chemical signatures of past environmental conditions. Using a drill core, the team carried out high-resolution geochemical analyses that capture subtle variations in chemistry and carbon isotopes, central component of Earth’s climate system.

The key advance came from combining these measurements with cyclostratigraphy, a method that identifies the imprint of regular climate cycles driven by small, predictable variations in Earth’s orbit around the Sun. These orbital cycles influence climate in a rhythmic way and leave repeating patterns in sedimentary rocks. By recognizing and quantifying these patterns, the researchers transformed a long sequence of rock strata into a precise, internally consistent timeline anchored directly in the geological record.

This new “rock clock” has made it possible, for the first time, to determine the timing and duration of a major global climate disturbance known as the DrumIan Carbon isotope Excursion (DICE). Beyond refining the geological timescale of the Cambrian, the results allow rock layers and fossil records from different continents to be correlated more accurately. They also provide new insights into how Earth’s climate system and early animal ecosystems responded to natural climate change in a greenhouse world, half a billion years ago.

Funded by an Ambizione grant from the Swiss National Science Foundation (SNSF), the study was carried out at the University of Lausanne in collaboration with researchers from partner institutions in Danemark (University of Copenhagen, Geological Survey of Denmark and Greenland), the United States (George Mason University) and Belgium (University of Liège).

Source : V. Jamart, Damien Pas, Linda A. Hinnov, Jorge E. Spangenberg, Thierry Adatte, Arne T. Nielsen, Niels H. Schovsbo, Nicolas Thibault, Michiel Arts & Allison C. Daley, Astronomical calibration of the middle Cambrian in Baltica: global carbon cycle synchronization and climate dynamics . Nature Communication (2026).

 

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Journal

Nature Communications

DOI

10.1038/s41467-026-70651-5 

Article Title

Astronomical calibration of the middle Cambrian in Baltica: global carbon cycle synchronization and climate dynamics

Article Publication Date

13-Mar-2026

 

Past intensive whaling threatens the future of bowhead whales

Commercial whaling has left the bowhead whale vulnerable for many generations to come.

University of Copenhagen

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A unique collection of prehistoric bowhead whale bones, dating back 11,000 years, reveals a previously untold story of the relative impacts of humans on nature.

The time series of ancient fossils show that commercial hunting of bowhead whales, which spanned 400 years and ceased less than a century ago in 1931, has left irreversible destructive traces in the species’ genetics. This could have serious consequences for the long-term vulnerability of the species.

Researchers from the University of Copenhagen led an international team to study this unique collection of fossils using DNA, stable isotopes, and palaeoclimate data. Their findings show that the bowhead whale has been remarkably resilient to climate changes of the past 11,000 years, but despite this, recent human activity has left lasting impacts that may impact their long-term survival.

“Our study shows the bowhead whale is an extremely robust species. But the visible loss of genetic diversity caused by commercial whaling revealed by our analysis is only the tip of the iceberg. The decline in diversity and fitness is an ongoing process and will continue far into the future,” says lead author Michael V. Westbury, former assistant professor at the University of Copenhagen and now associate professor at DTU.

“Bowhead whales are a species that can withstand almost anything—except humans,” he adds.

Inbred whales are weaker whales

The study, published online in the journal Cell and featured on the cover of the April 2 issue, is based on the analysis of an 11,000-year time series of bowhead whale fossils from the Canadian Arctic Archipelago and from the Svalbard Archipelago (Norway). Hundreds of bones were examined using radiocarbon dating, palaeogenomics, and stable isotopes, and were compared with present-day bowhead whales from the same regions. In addition, the >850 radiocarbon dated fossils were integrated with palaeoclimate data to model bowhead whale habitat across the past 11,000 years, a period known as the Holocene. This allowed the researchers to explore links between past climatic change, bowhead whale genomics and ecology, and changes in species distribution since the end of the last Ice Age.

The analyses show that bowhead whale populations in the North Atlantic remained stable throughout the Holocene – until 500 years ago. Populations lost genetic diversity and became increasingly structured during commercial whaling.

Based on their 11,000-year time series of bowhead whale genetic diversity, the researchers estimated how the species’ genetic diversity will evolve in future generations. The results show that diversity will continue to decline as a direct result of commercial whaling, even if populations stay stable. This may severely impact the species’ resilience to a changing climate.

“A species’ genetic diversity is like a Swiss Army knife. The bigger the knife, the more tools a species has in their response to stressors,” explains senior author Eline Lorenzen, professor of molecular natural history at the Globe Institute, University of Copenhagen.

“Genetic diversity is what species depend on when facing stress or change, such as disease or environmental change. The more diversity a species has, the better its chances of survival,” she says.

Commercial whaling

Commercial hunting of bowhead whales began around year 1540, driven by a huge demand for whale oil used in lamps. Whalers from England, the U.S., the Netherlands, and Germany headed north to the Arctic Ocean. The pursuit of whales included Danish sailors, particularly from the Wadden Sea islands, who joined Dutch whaling expeditions. Evidence of this can still be seen on the island of Rømø, where a fence built from bowhead whale bones brought back from a 1700s whaling voyage still stands.

Bowhead whale protection was put in place in 1931 with the signing of an international convention banning the harvest of all species in the right whale family (Balaenidae). By then, the global population was so depleted that hunting bowhead whales was no longer economically viable.

Gone is gone

The outlook for bowhead whales is bleak. Even if population sizes increase, the genetic diversity that is gone has been lost forever.

“Our study provides an 11,000-year ecological baseline for the bowhead whale. We provide insight into the species’ long-term resilience to past climatic changes, but also a clear understanding of the relative impact of commercial whaling. In evolutionary terms, that impact has been massive. The biological consequences of whaling will extend many generations into the future,” says Eline Lorenzen.

The study was supported by Villum Fonden and the Independent Research Fund Denmark.

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Links to available images

Image 1 Bowhead whales are the only baleen whale species found in Arctic waters year-round. They are among the most biologically distinctive mammals, combining extreme longevity, slow life histories, and exceptional insulation through their thick blubber layer, which constitutes 40-50% of their body. Image: Fredrik Christiansen.

Image 2 Bowhead whale fossil found on a beach in the Canadian Arctic Archipelago. Photo: Art Dyke.

Image 3 and Image 4 Bowhead whale fossil from the Canadian Museum of Nature, collected by geologist and co-author of the study Art Dyke. The bowhead whale fossil chronologies analysed in this study were originally collected and radiocarbon dated to determine Holocene sea ice dynamics. Photo: Michael V Westbury.

Image 5 Painting ‘Dutch whalers near Spitsbergen’ by Abraham Storck 1690. Inventory number 2010.2102, collection National Maritime Museum, Amsterdam.

Image 6 Graphical abstract of the study.

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Journal

Cell

DOI

10.1016/j.cell.2026.02.022 

Article Title

Four centuries of commercial whaling eroded 11,000 years of population stability in bowhead whales

Article Publication Date

17-Mar-2026

European regions with the highest poverty levels are the most vulnerable to the health effects of air pollution

A new study analyses how socioeconomic factors and the transition to renewable energy influence the risk of mortality related to air pollution

Barcelona Institute for Global Health (ISGlobal)

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Barcelona, March 19, 2026 (EMBARGOED) -. Socioeconomic factors are widely recognized as potential modifiers of the relationship between air pollution and mortality, but the available evidence remains limited. In this context, a new study led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by the ”la Caixa” Foundation, in collaboration with the Barcelona Supercomputing Center–Centro Nacional de Supercomputación (BSC-CNS), analysed how socioeconomic conditions and the transition to renewable energy in Europe influence vulnerability to air pollution. The results, published in Nature Medicine, show that regions with higher poverty levels and lower adoption of renewable energy are those with the highest risk of mortality associated with air pollution.

The study analysed a daily mortality database with 88.8 million deaths from the EARLY-ADAPT project (https://www.early-adapt.eu) between 2003 and 2019 in 653 contiguous regions of 31 European countries, including a population of 521 million people. Daily levels of air pollutants—fine particulate matter (PM2.5), coarse particles (PM10), nitrogen dioxide (NO2), and the 8-hour maximum daily ozone (O3)—were estimated using advanced machine learning models.

The researchers also incorporated regional socioeconomic indicators and data on renewable energy consumption, obtained from Eurostat’s regional statistics database. The epidemiological models included these socioeconomic and renewable energy variables to describe how the mortality risks of air pollution are different between populations, and how they evolved over the present century.

The higher the poverty, the greater the vulnerability to air pollution

The health risks of air pollution are not determined by pollution levels alone. They also depend on how vulnerable people are. Even when regions experience similar air pollution, the health consequences can differ greatly because of socioeconomic and demographic conditions.

The study showed regions with higher gross domestic product (GDP) per capita, lower poverty rates, and higher life expectancy, mainly in Northern and Western Europe, presented a lower risk of mortality associated with air pollution. In contrast, the most disadvantaged areas, located in Southern and Eastern Europe, recorded significantly higher risks, even doubling those of regions with better socioeconomic conditions.

These inequalities have also evolved differently over the present century. Wealthier regions experienced a significant decrease in the risks associated with PM2.5, PM10 and NO2 between 2003 and 2019. In contrast, regions with lower income or life expectancy saw only small improvements—or in some cases even increases—in mortality risks associated with these pollutants during the study period.

According to the research team, several mechanisms could explain these patterns. “It is not just that poorer regions are more polluted. Wealthier regions usually have better-equipped healthcare systems, more comprehensive public health programs, and greater social awareness of the effects of air pollution, as well as a higher capacity to implement environmental policies,” notes Zhaoyue Chen, ISGlobal researcher and first author of the study. “Quantifying the mortality risks attributable to air pollution in each region and period can help identify the most vulnerable populations more accurately,” he adds.

The effect of adopting renewable energy

The study also analysed how the transition to renewable energy affects mortality related to air pollution through two complementary pathways: by reducing air pollution levels and by lowering population vulnerability to air-pollution-related health risks.

The analyses show that the increase in renewable energy during the present century is associated with a reduction in air pollution of 15% for fine PM, 54% for coarse PM, and 20% for NO2. This represents a decrease in the mortality due to air pollution of 12% for fine PM, 52% for coarse PM, and 20% for NO2.

In addition, regions with higher and rapid renewable energy adoption experienced lowering population vulnerability to the health impacts of air pollution. Renewable energy adoption is a key component of sustainable environmental and climate policy frameworks and is often accompanied by social and infrastructural improvements—such as cleaner public transport, greener cities, more walkable urban design, cleaner technologies, and stronger environmental regulations—that can reduce communities’ susceptibility to air pollution.

However, progress has been uneven across the continent. Northern countries generally show high and rapid growth in the adoption of clean energy, while several Southern and Eastern countries, such as Malta, Cyprus, Italy and Poland, continue to show a relatively high dependence on fossil fuels.

“Western European countries generally tended to invest more resources in clean energy, green infrastructure, and stricter emission controls. Eastern European countries, on the other hand, have often relied more heavily on external funding and remain at an early stage of integrating renewable energy and pollution-control measures,” says Joan Ballester Claramunt, principal investigator of the EARLY-ADAPT project and senior author of the study.

Equity as a core of environmental policies

The study results highlight the need to integrate health equity into environmental policies, prioritizing pollution reduction in the most affected areas, and strengthening public health infrastructure. “It is urgent to expand environmental and health monitoring to identify disparities, guide equitable strategies, and ensure that resources reach those who need them most,” emphasizes Carlos Pérez García-Pando, ICREA and AXA Professor at the BSC’s Earth Sciences Department and co-author of the study.

According to the research team, although the analysis focused on Europe, the implications are global, as in many low- and middle-income countries, rapid urban growth and industrial expansion advance faster than investments in clean energy and environmental protection, which could further increase population vulnerability to the effects of pollution.

Health alerts of air pollution for vulnerable populations

The air pollution estimates and epidemiological models of the study were used in Forecaster.Health (https://forecaster.health/), an impact-based early warning system issuing alerts of mortality risks due to temperature and air pollution for vulnerable population groups.

 

Reference:

Chen, ZY., Achebak, H., Huang, W., Paniello-Castillo, B., Petetin, H., Méndez Turrubiates, RF., Pérez García-Pando, C., Ballester, J. Socioeconomic and energy transition disparities in acute air pollution–related mortality across Europe. Nature Medicine, 2026. https://www.nature.com/articles/s41591-026-04293-x

 

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Journal

Nature Medicine

DOI

10.1038/s41591-026-04293-x 

Method of Research

Meta-analysis

Subject of Research

People

Article Title

Socioeconomic and energy transition disparities in air pollution-related mortality across Europe

Article Publication Date

19-Mar-2026