Coral calcification benefits from human hormone injections

Society for Experimental Biology

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Coral injection protocol

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Credit: Clemence Forin

Researchers have identified how thyroxine, a human thyroid hormone, can positively influence the life-critical calcification in soft corals, and have developed a unique technique for injecting molecules into coral tissues.

“We understand a lot about hormones in vertebrates, but much less about hormones in invertebrate animals such as corals,” says Clémence Forin, a PhD student at the Scientific Centre of Monaco. “We wanted to learn more about how they process hormones to find out how they are involved into the calcification process.”

A major barrier to researching the role and regulation of hormones in corals has been the lack of established techniques. To address this, Ms Forin and her team set out to develop a novel injection method that would allow them to insert hormones into the corals and monitor how they affected the calcification process.

“The major benefits of this injection method are that we can accurately inject the same concentration of hormones each time, and that we can trace where it is going inside the organism,” says Ms Forin. “We needed to make sure that all the hormones made it to the cells of interest and that soluble hormones wouldn’t be lost in the surrounding seawater.”

After screening many different widely available human hormones for pro-calcification effects, they identified a prime candidate in thyroxine. In humans and other vertebrates, thyroxine contributes to a variety of important functions such as growth and metabolism and has been associated with calcium transport.

“We found that thyroxine had a positive effect on the coral’s calcification process,” says Ms Forin. Using an ELISA (Enzyme-Linked Immunosorbent Assay), they were able to detect and quantify the hormone’s processing and activity within the coral.

This finding raises interesting questions about the evolution of animal physiology. “If the coral is able to process and use the thyroxine, then it means that specific metabolic pathways have been conserved,” says Ms Forin. “The big question now is how these corals utilise thyroxine in their natural habitat.”

This research is being presented at the Society for Experimental Biology Annual Conference in Antwerp, Belgium on the 9th July 2025.

FAU Harbor Branch receives $1M grant to study gulf’s mesophotic coral habitats

Florida Atlantic University

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The animation shows surface chlorophyll concentrations – comparable to fluorescence – generated by a research model that simulates both ocean physics (such as currents, temperature and salinity) and biogeochemical processes (including nutrient cycling, algal growth and mortality). It covers the period from August 1 to Sept. 30, 2011. Chlorophyll levels change over time and are carried by ocean currents, though the currents themselves are not directly depicted in the animation.

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Credit: FAU Harbor Branch

Mesophotic coral ecosystems (MCEs) are important coral ecosystems found between 30 and 150 meters deep in oceans worldwide including the Gulf of America. They support diverse marine life and important fisheries but remain poorly understood. Unlike shallow reefs, MCEs depend on nutrients from the deep ocean from upwelling or river plumes, like those from the Mississippi and Apalachicola rivers. These nutrient flows support growth of marine phytoplankton (i.e. tiny floating algae), which is an important source of organic matter (food) that sustains the corals and other marine species.

However, scientists have limited knowledge of the food sources and the processes that sustain them on the West Florida Shelf, particularly on the southern portion of the shelf, which lies largely beyond the influence of river plumes.

Florida Atlantic University’s Harbor Branch Oceanographic Institute has received a $999,664 grant from the Florida RESTORE Act Centers of Excellence Program (FLRACEP) for a three-year project titled, “Influences of Upwelling and Riverine Nutrient Plumes on the Mesophotic Coral Ecosystems of the West Florida Shelf.”

FLRACEP is a state-led initiative that funds research to support the long-term health and sustainability of Florida’s Gulf Coast. Created in response to the Deepwater Horizon oil spill and funded by the RESTORE Act, the program is managed by the Florida Institute of Oceanography. It supports collaborative projects among top scientists and institutions, focusing on ecosystem restoration, fisheries, coastal resilience and offshore energy safety. The goal is to provide science-based solutions that guide environmental protection and sustainable growth in the gulf region.

The FAU project seeks to understand how ocean currents and nutrients from land influence the health and productivity of MCEs along the edge of the West Florida Shelf, which is home to one of the largest MCEs in the gulf. These deep coral habitats are built on exposed rocky seafloor and support vibrant communities of corals, sponges and fish – many of which are economically important and rely on these areas for spawning. While a few protected areas have been established to safeguard these fish populations, much of the West Florida Shelf remains open to fishing, and large areas have yet to be fully explored or mapped.

The project team, spearheaded by Mingshun Jiang, Ph.D., principal investigator and an associate research professor at FAU Harbor Branch, includes researchers from Florida State University and Florida Agricultural and Mechanical University. The team will identify areas of high ecological value and describe the benthic communities.

Through four research cruises, scientists will study both nutrient-rich sites in the north and nutrient-poor areas in the south. The team will use underwater Remotely Operated Vehicles to capture images and collect samples of corals, plankton and sediments. A suite of instruments will be deployed to measure currents, nutrients and sediment parameters including nutrient supplies from the sediment. At the same time, a novel imaging system called AUTOHOLO, developed by FAU Harbor Branch researchers, will be deployed to document plankton communities over the MCEs.

Researchers also will place instruments on the seafloor to document seasonal environmental conditions including temperature, currents, nutrients, dissolved oxygen and pH. All this information will be used to develop a computer model at FAU Harbor Branch that provides a broad picture of environmental conditions and fish larval transport.

“The mesophotic coral ecosystems along the West Florida Shelf are some of the gulf’s most valuable yet least understood habitats,” said Jiang. “Our goal is to uncover how ocean currents and nutrient flows sustain these valuable ecosystems and the marine life they support. These systems are influenced by complex physical and biological processes, and many questions remain about how food reaches these depths and how it varies across the shelf. By filling these critical knowledge gaps, our research will contribute to science-based management – helping protect these ecosystems and the fisheries that depend on them, especially in the face of environmental change.”

This project will generate a detailed dataset on ocean conditions, water movement, and marine life across key mesophotic coral sites, including areas near features like De Soto Canyon. Researchers will map seafloor habitats and compare reef health in areas with different levels of nutrient availability. The study will also shed light on what drives upwelling, where nutrients and organic matter come from and how they reach the reefs. By examining specific water layers above the MCEs, the team will better understand the conditions that shape these ecosystems.

The project team will work closely with NOAA scientists to study how fish larvae disperse, including economically important species like gag (Mycteroperca microlepis) and red grouper (Epinephelus morio), which are heavily fished and vulnerable to environmental problems like red tides. Data will also be collected on the distribution of other less-studied fish associated with the MCEs that are caught as fisheries bycatch. Data collected from this project will be shared with NOAA scientists who also study MCEs in the gulf.

“By delivering the kind of high-quality, interdisciplinary science that’s been missing for these coral ecosystems, this project will directly support enhanced management and stronger protection of mesophotic habitats in the gulf,” said James M. Sullivan, Ph.D., executive director of FAU Harbor Branch. “The data gathered will not only fill major knowledge gaps but also give managers the tools they need to make informed decisions – from designing conservation strategies to identifying new marine protected areas. These ecosystems support valuable fisheries and biodiversity, and outcomes from this project will help ensure their resilience for the future.”

Co-principal investigators of the project are Jordon Beckler, Ph.D., an associate research professor at FAU Harbor Branch; Aditya R. Nayak, Ph.D., an associate professor, Department of Ocean and Mechanical Engineering within FAU’s College of Engineering and Computer Science and a research scientist at FAU Harbor Branch; Sandra Brooke, Ph.D., research faculty, Coastal and Marine Laboratory, FSU; and Steven Morey, Ph.D., a professor of environmental sciences at FAMU

- FAU -

Deep coral ecosystems [VIDEO] 

Mesophotic coral and crinoids on Bright Bank, Florida Garden Banks National Marine Sanctuary. 

Credit

Marine Applied Research and Exploration, NOAA

A mesophotic reef in the northern gulf shwoing diverse soft corals. 

Credit

National Centers for Coastal Ocean Science, NOAA

About Harbor Branch Oceanographic Institute:
Founded in 1971, Harbor Branch Oceanographic Institute at Florida Atlantic University is a research community of marine scientists, engineers, educators, and other professionals focused on Ocean Science for a Better World. The institute drives innovation in ocean engineering, at-sea operations, drug discovery and biotechnology from the oceans, coastal ecology and conservation, marine mammal research and conservation, aquaculture, ocean observing systems and marine education. For more information, visit www.fau.edu/hboi.

 

About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, Florida Atlantic serves more than 30,000 undergraduate and graduate students across six campuses located along the Southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, Florida Atlantic embodies an innovative model where traditional achievement gaps vanish. Florida Atlantic is designated as a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report, and holds the designation of “R1: Very High Research Spending and Doctorate Production” by the Carnegie Classification of Institutions of Higher Education. Florida Atlantic shares this status with less than 5% of the nearly 4,000 universities in the United States. For more information, visit www.fau.edu

New catalyst enables triple-efficiency decomposition of ammonia for clean hydrogen

Developed a polyol process-based ruthenium catalyst synthesis method with ammonia decomposition performance three times higher than conventional catalysts

National Research Council of Science & Technology


Group photo of the research team (from left Dr. Unho Jung, Dr. Kee Young Koo, Dr. Byeong-Seon An, Dr. Yongha Park)view more
Credit: KOREA INSTITUTE OF ENERGY RESEARCH(KIER)

A research team led by Dr. Kee Young Koo from the Hydrogen Research Department at the Korea Institute of Energy Research (President: Yi Chang-Keun, hereafter referred to as KIER) has developed a novel and more cost-effective method for synthesizing ammonia decomposition catalysts. This new approach enables more efficient hydrogen production from ammonia and is expected to make a significant contribution to the realization of a hydrogen economy.

Composed of three hydrogen atoms and one nitrogen atom, ammonia has a high hydrogen content, making it a promising hydrogen carrier for long-distance transport and large-scale storage. With global infrastructure for its transport and storage already in place, ammonia offers a more economical means of hydrogen delivery compared to other carriers. However, the technology for decomposing ammonia to produce hydrogen at the point of demand is still in the early stages of development.

The core of this technology lies in the use of ruthenium (Ru) catalysts. Ruthenium enables rapid ammonia decomposition at lower temperatures—between 500°C and 600°C—which is over 100°C lower than that required by other catalysts. The challenge, however, is that ruthenium is an extremely rare metal found in only a few countries, making it difficult to procure.

Until now, ruthenium has been used in nanoscale form to maximize performance even in small quantities. However, the large-scale production of nanocatalysts involves complex processes and high manufacturing costs, which hinder the commercialization of ammonia decomposition technology.

In response, the research team developed a novel ruthenium catalyst synthesis method based on the polyol process, aimed at improving the economic viability of the catalyst. The catalyst produced through this method demonstrated more than three times higher ammonia decomposition performance compared to conventional catalysts.

The polyol* process applied by the research team is commonly used to synthesize metals into nanoparticles. In conventional processes, capping agents are added to prevent the particles from clumping together, but this makes the process more complex and increases costs. To address this, the team devised a method to control nanoparticle aggregation without the use of capping agents.


* Polyol: A viscous, sticky liquid alcohol containing multiple –OH (hydroxyl) groups, commonly used in processes that reduce metals into nanoparticles. Representative examples include ethylene glycol, glycerol, and butylene glycol.


The research team focused on the fact that the length of organic molecules known as carbon chains affects the degree of particle aggregation. They hypothesized that by controlling the structure and length of these carbon chains, nanoparticle aggregation could be effectively suppressed without the need for additives.


* Carbon chain: A structure in which carbon atoms are bonded together; its length varies depending on the number of carbon atoms contained in the molecule.


Through experiments, the research team confirmed that using butylene glycol, which has a long carbon chain, allowed 2.5nm sized ruthenium particles to be uniformly dispersed without the need for capping agents. They also verified the formation of 'B5 sites'*—the active sites where hydrogen production reactions occur.


* B5 site: A highly reactive structural site where three ruthenium atoms are positioned on a stepped surface, with two additional atoms located on the terrace edge above them, facilitating enhanced catalytic activity.




The resulting catalyst significantly outperformed existing catalysts. Compared to conventional ruthenium catalysts that did not use butylene glycol, the activation energy* was reduced by approximately 20%, and the hydrogen formation rate increased by 1.7 times. Furthermore, when comparing ammonia decomposition performance per unit volume, the catalyst demonstrated more than three times higher efficiency than those produced using conventional synthesis methods, highlighting its excellent economic potential.**


* Activation energy: The minimum amount of energy required for a chemical reaction to occur, expressed in kJ·mol⁻¹ (kilojoules needed per mole of molecules for the hydrogen production reaction). The catalyst developed by the research team showed an activation energy of 49.8 kJ·mol⁻¹.

** Hydrogen formation rate: In this study, it is measured in mmolH₂·gcat⁻¹·h⁻¹, which indicates the amount of hydrogen produced per gram of catalyst per hour. The catalyst developed by the research team achieved a hydrogen formation rate of 1,236 mmolH₂·gcat⁻¹·h⁻¹.


Dr. Kee Young Koo, the lead researcher, stated, “The ammonia decomposition catalyst synthesis technology developed in this study is a practical solution to overcome the limitations and cost issues associated with mass production of conventional nanocatalysts. It is expected to contribute to the localization and commercialization of ammonia decomposition catalyst technology.” She added, “We plan to move forward with performance verification through mass production of pellet-type catalysts and application in various ammonia cracking systems.”

This achievement was published as a cover paper in Small (Impact Factor 12.1), a prestigious journal in the field of nanotechnology, and was carried out with support from the Global Top Strategic Research Program of the National Research Council of Science & Technology, under the Ministry of Science and ICT.


* Paper Information: https://doi.org/10.1002/smll.202407338

(Published on April 23, 2025 / Selected for the Inside Front Cover)

[Photo 2] Dr. Kee Young Koo conducting a catalyst synthesis experiment using the newly developed technology

The catalyst developed by the research team (left powder form, right pellet form)

Credit

KOREA INSTITUTE OF ENERGY RESEARCH(KIER)

Journal

Small

DOI

10.1002/smll.202407338

Article Title

Polyol-Intermediated Facile Synthesis of B5-Site-Rich Ru-Based Nanocatalysts for COx-Free Hydrogen Production via Ammonia Decomposition

 

Semiconductors show promise for efficient carbon capture and utilization

Innovative catalyst design enables the selective conversion of carbon dioxide into methanol

Institute of Science Tokyo

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This work sheds light on a new strategy to design semiconductor-based catalysts for challenging reactions, including carbon capture via carbon dioxide conversion to methanol.

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Credit: Institute of Science Tokyo

A new palladium-loaded amorphous InGaZnOx (a-IGZO) catalyst achieved over 91% selectivity when converting carbon dioxide to methanol, report researchers from Japan. Unlike traditional catalysts, this system leverages the electronic properties of semiconductors to generate all the species necessary for the conversion reaction. This study demonstrates novel design principles for sustainable catalysis based on electronic structure engineering.

The global push for carbon neutrality hinges on our ability to not just capture carbon dioxide (CO2), but also transform it into valuable resources. One of the most promising avenues is converting CO2 into methanol (CH3OH), a key building block in the chemical industry and a potential clean energy carrier in a hydrogen-based economy. While this route offers a compelling pathway for reducing greenhouse gas emissions while creating value, its implementation still faces technical challenges.

Conventional catalysts for CO2-to-CH3OH conversion, such as those based on copper-zinc oxide systems, suffer from poor selectivity. They tend to produce undesirable carbon monoxide (CO) as a byproduct, which lowers CH3OH yield and undermines both efficiency and environmental benefits. This has prompted researchers to explore strategies beyond conventional catalyst design, leveraging the intrinsic electronic properties of semiconductor materials.

In a recent study, a research team led by Professor Hideo Hosono from the MDX Research Center for Element Strategy at Institute of Science Tokyo (Science Tokyo), Japan, presents a novel approach to overcome current limitations. Their findings, which were made available online on June 16, 2025 and  published in Volume 147, Issue 26 of the Journal of the American Chemical Society on July 02, 2025, reveal how n-type oxide semiconductors can be engineered into highly efficient catalysts for CO2-to-CH3OH conversion. This work was co-authored by Professor Masaaki Kitano, and Assistant Professor Masatake Tsuji, also from Science Tokyo, and conducted in collaboration with Mitsubishi Chemical Corporation.

The researchers focused on amorphous indium-based oxides, particularly a-InGaZnOx (a-IGZO), which is widely used as a semiconductor to drive pixels in display technology. They synthesized fine powders of these oxides to maximize their surface area—a crucial factor for catalytic activity. Then, the team evaluated the catalytic performance of the synthesized materials, both independently and when loaded with palladium (Pd) nanoparticles.

The key breakthrough came from understanding how the electronic structure of these semiconductor catalysts drives the desired conversion reaction. Unlike traditional catalysts that rely primarily on surface chemistry, the a-IGZO system features unique electronic properties. Specifically, its conduction band minimum is aligned with the so-called ‘universal hydrogen charge transition level (UHCTL),’ which is the energy level in a semiconductor where H+ and H− ions are equally stable. UHCTL is located at ~4.5eV from the vacuum level.

This alignment allows the catalyst to generate both positively and negatively charged hydrogen species simultaneously, which are essential for the multi-step process of converting CO2 into CH3OH. Moreover, the Pd nanoparticles serve as suppliers of hydrogen, dissociating hydrogen molecules into atomic hydrogen(H0) and transferring them to the semiconductor surface. High carrier concentration in oxide semiconductors facilitates H0 tunneling through the Schottky barrier of the Pd/semiconductor interface.

Thanks to these mechanisms, the Pd-loaded a-IGZO catalyst achieved over 91% selectivity for CH3OH production—a notable improvement over conventional systems. “Our work shows that realization of bipolar state (H+ and H− ) of hydron is a key to efficient and highly selective methanol synthesis from CO2, and the design principle for the catalyst is to choose n-type oxide semiconductors with conduction band minimum close to UHCTL, and high carrier concentration,” says Hosono.

Overall, the proposed semiconductor-based approach could mark a paradigm shift in catalyst design, moving from traditional strategies focused on surface chemistry to new ones based on electronic structure. “Our findings not only demonstrate the effectiveness of utilizing electrons, holes, hydrogen species, and their dynamics within semiconductors for CO2 hydrogenation, but also suggest new design guidelines for chemical devices such as catalysts and batteries,” concludes Hosono. These findings will hopefully accelerate the development of more efficient carbon capture and utilization technologies.

 

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About Institute of Science Tokyo (Science Tokyo)
Institute of Science Tokyo (Science Tokyo) was established on October 1, 2024, following the merger between Tokyo Medical and Dental University (TMDU) and Tokyo Institute of Technology (Tokyo Tech), with the mission of “Advancing science and human wellbeing to create value for and with society.”

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Journal

Journal of the American Chemical Society

DOI

10.1021/jacs.5c03910 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

CO2 Conversion to Methanol by Hydrogen Species on n‐Type Oxide Semiconductors

Article Publication Date

9-Jul-2025

 

Teams develop CO₂ capture-conversion tandem system adaptable to a wide range of CO₂ concentrations

Offers sustainable carbon-neutral fuel production

Industrial Chemistry & Materials

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Tandem CO2 capture and hydrogenation system using Rb-loaded zeolite and Ni/CeO2 or Cu/ZnO/Al2O3 catalysts are successfully developed, realizing efficient CH4 and CO production from a wide range of CO2 concentrations from 0.04% (air) to 10% (exhaust gas).

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Credit: Ken-ichi Shimizu and Akihiko Anzai, Hokkaido University, Japan

CO2 concentrations vary widely depending on the source, ranging, for example, from about 0.04% in the atmosphere to about 10% in flue gases. Moreover, these gas streams contain a significant amount of O2 (about 10%), a potent oxidizing agent. To achieve carbon neutrality, it is necessary to develop a robust process that can convert CO2 over a wide concentration range, even in the presence of O2. However, current technology does not offer a single unified approach that can efficiently handle CO2 conversion from trace to high concentrations. To meet this challenge, researchers at Hokkaido University and collaborators developed a tandem CO2 capture and conversion system free of precious metals that accommodates a wide range of CO2 concentrations under oxygen-rich conditions. Their work is published in the journal Industrial Chemistry & Materials on June 13, 2025.

"We aim to develop a unified process capable of efficiently converting CO2 and NOx contained in combustion exhaust gases from thermal power plants and other sources into resources with high yields," explains Ken-ich Shimizu, a professor at Hokkaido University. Among various carbon capture, utilization, and storage (CCUS) strategies, integrated CO2 capture and reduction (CCR) with hydrogen using dual-functional materials (DFMs) has recently gained attention as a promising approach for utilizing low-concentration CO2 in O2-rich conditions such as air or flue gases. However, this method remains unsuitable for treating high-concentration CO2 streams exceeding 10%. This limitation stems from the inherent properties of conventional DFMs, which typically contain basic metal oxides such as CaO. Although these materials capture CO2 via a bulk diffusion mechanism and exhibit substantial CO2 uptake capacity, only the surface carbonates participate in the reaction, while the carbonates within the bulk remain largely inaccessible, thereby constraining the overall efficiency of CO2 utilization. To overcome these challenges, the developed tandem configuration separates the two functions. The zeolite adsorbent allows for rapid CO2 adsorption and complete desorption under controlled temperature changes. After desorption, the released CO2 flows into a separate catalytic reactor where it reacts with H2. Unlike conventional CCR designs, the strength of the tandem system design is its flexibility to independently optimize the active sites and reaction conditions for each step.

In evaluations using simulated flue gas (10% CO2, 10% O2), the Ni/CeO2 catalyst achieved 92% CH4 yield and over 99% selectivity at 300 °C, outperforming more than 100 conventional CCR systems that are intolerant to O₂. In parallel experiments, the Cu/ZnO/Al2O3 catalyst achieved 93% CO yield and an H2/CO ratio of 3.7 at 650 °C, providing an H2/CO ratio suitable for downstream syngas applications. The system was also evaluated in terms of direct air capture (DAC), producing CH4 from atmospheric CO2 (0.04%) with a maximum CH4 concentration of 0.7% and an average CH4 concentration of about 0.4%. The results show that 10 times the concentration of CH4 is produced from atmospheric CO2. From an efficiency perspective, the tandem system showed an energy efficiency (η) of 46% and a fuel production efficiency (FPE) of 83%, outperforming a comparable CCR system. The ability to operate continuously under normal pressure and high O2 concentration conditions is a significant technical advantage.

The research team proposes that this platform can be expanded to methanol synthesis and LPG synthesis in the future by combining it with an FT catalyst or a methanol synthesis catalyst. The combination of a modular design and a simple thermal cycle is expected to be applicable not only to large point sources, namely fossil-fuel-fired power gasification plants, but also to small distributed sources such as home and office. “In the future, we plan to continue improving the system and extend its applicability to real exhaust gases, including other acid gases such as NOx, as well as challenging conditions involving coexisting species like water vapor and SO2,” said Shimizu.

The research team includes Shinta Miyazaki, Akihiko Anzai, Masaki Yoshihara, Hsu Sheng Feng, Takashi Toyao, and Ken-ichi Shimizu from Institute for Catalysis, Hokkaido University, and Shinya Mine from National Institute of Advanced Industrial Science and Technology.

This research is funded by the “Moonshot Research and Development Program” (JPNP18016), commissioned by the New Energy and Industrial Technology Development Organization (NEDO), KAKENHI (23K20034, and 21H04626) from the Japan Society for the Promotion of Science (JSPS), the Joint Usage/Research Center for Catalysis, and the Grant-in-Aid for JSPS Fellows (24KJ0267).

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Industrial Chemistry & Materials is a peer-reviewed interdisciplinary academic journal published by Royal Society of Chemistry (RSC) with APCs currently waived. ICM publishes significant innovative research and major technological breakthroughs in all aspects of industrial chemistry and materials, especially the important innovation of the low-carbon chemical industry, energy, and functional materials. Check out the latest ICM news on the blog.

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Journal

Industrial Chemistry and Materials

DOI

10.1039/D5IM00028A 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Continuous direct air capture and conversion tandem system applicable to a wide range of CO₂ concentrations

 

Prolonged humid-heat seasons in eastern China threaten public health, especially for the elderly and children

Institute of Atmospheric Physics, Chinese Academy of Sciences

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The westward extension of the western North Pacific subtropical high leading to a prolonged season of compound humid–heat extremes.

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Credit: Xinyue SUN

When scorching temperatures meet high humidity, the air can feel suffocating, much like being trapped in a sauna. "It's no longer just hot—it's dangerous," says Prof. Miaoni Gao, a climate scientist from Nanjing University of Information Science and Technology, China.

Unlike dry heat, humid conditions limit the body's ability to cool itself through sweating, increasing the risk of heat-related illnesses. In recent years, these compound heat–humidity extremes—also known as humid-heat waves—have become more frequent and intense across eastern China. Vulnerable groups such as the elderly and children are particularly affected, as their bodies are less capable of adapting to extreme conditions. As global warming accelerates, humid-heat stress is emerging as a major yet under-recognized public health challenge in densely populated regions.

In a new study published in Atmospheric and Oceanic Science Letters, Prof. Miaoni Gao's team reports that compound heat–humidity extremes in eastern China are now lasting longer than ever before, significantly increasing health risks, particularly for the elderly and young children. Based on climate records dating back to 1961, the researchers found that the active season for compound heat–humidity extremes has expanded, especially in the Yangtze–Huaihe region and South China. Over the past decade, the season in South China alone has lengthened by about one month.

What's driving this trend? "It's the western expansion of the Western North Pacific Subtropical High," explains Prof. Gao. This climatic shift intensifies solar radiation and drives persistent warm air and moisture into eastern China, amplifying and prolonging the active season of compound heat–humidity extremes.

But heatwaves aren't just weather events—they're also public health emergencies. In 2023 alone, over 37,000 heat-related deaths were recorded nationwide. The study found that physiologically vulnerable groups—primarily the elderly and young children—now make up 39% of the total population exposed to compound heat–humidity extremes. Notably, one-third of the increase in exposure can be attributed to the lengthening of the heatwave season. In South China, this proportion soars to 56%.

As China's population continues to age, with over 200 million people now aged 65 or older, the convergence of demographic vulnerability and extended heatwave seasons could lead to a major public health crisis.

The researchers call for urgent action: "We can no longer rely on fixed-schedule summer warnings," says co-author Ms. Xinyue Sun. "We need dynamic early warning systems that reflect the changing timing of heatwave seasons, along with targeted health interventions to protect the most vulnerable populations."

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Journal

Atmospheric and Oceanic Science Letters

DOI

10.1016/j.aosl.2025.100663 

Article Title

Prolonged seasons of compound heat–humidity extremes amplify vulnerable population exposure in eastern China