USF study: Ancient plankton hint at steadier future for ocean life

Findings point to stable upwelling that continued fueling plankton and fisheries in past warm periods

University of South Florida

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Patrick Rafter, University of South Florida

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Credit: USF

Key takeaways:

• By analyzing rare nitrogen isotopes in 5-million-year-old plankton fossils, researchers reconstructed past Pacific Ocean conditions to better forecast the future.

• Even during the warmer Pliocene Epoch, nutrient-rich upwelling in the tropical Pacific remained stable, sustaining marine productivity.

• The findings challenge predictions of a fisheries collapse.

TAMPA, Fla. (Oct. 1, 2025) – A team of scientists has uncovered a rare isotope in microscopic fossils, offering fresh evidence that ocean ecosystems may be more resilient than once feared.

In a new study co-led by Patrick Rafter of the University of South Florida, researchers show that warming in the tropical Pacific — home to some of the world’s most productive fisheries — may not trigger the severe declines predicted by earlier models. Instead, the region’s fisheries could remain productive even as ocean temperatures rise.

The paper will publish online in Science on Thursday, Oct. 2, 2025, at 2 p.m. ET and is embargoed until that time.

Rafter, a chemical oceanographer at USF’s College of Marine Science, said the findings are welcome news.

“Our measurements suggest that, on a warmer planet, the availability of marine nutrients to fuel plant growth and fisheries may not necessarily decline,” Rafter said.

The paper highlights a cutting-edge approach to predicting future ocean conditions by examining the distant past. Further study could reveal more reason for optimism about global ocean productivity.

The team turned to the Pliocene Epoch, 5.3 to 2.6 million years ago, when ocean warming trends were similar to today’s. By analyzing nitrogen isotopes preserved in the shells of tiny plankton called foraminifera (forams), researchers reconstructed nutrient characteristics in the tropical Pacific.

Today, nutrient upwelling in the region supports vast blooms of plankton — the base of the marine food chain. During warming events like El Niño, this process weakens, reducing nutrients and harming fisheries. Previous studies suggested such conditions could become permanent in a hotter world.

But Rafter and his colleagues found no evidence of reduced nitrate concentrations — a key nutrient for plankton — in the eastern tropical Pacific over the last five million years. The results suggest that nutrient upwelling and biological productivity remained stable despite higher global temperatures.

“We’ve used this nitrogen isotope like a geochemical fingerprint,” Rafter said. “We don’t have a time machine, but we can use our detective toolkit to reconstruct what happened in the ocean the last time Earth was as warm as today.”

Extracting the isotopes required painstaking work. Researchers from USF, the University of Massachusetts Boston, the University of California Irvine and Princeton University hand-sorted foram shells from deep-sea cores, dissolved them and analyzed the nitrogen isotopes with the help of bacteria.

“Analyzing nitrogen isotopes derived from forams has allowed us to reconstruct the past with precision,” Rafter said. “We can compare these past conditions to today and make better predictions about the future. The methods we’ve used represent a big step forward in improving our predictive capabilities.”

For Jesse Farmer, co-lead author and assistant professor at UMass Boston, the findings provide cautious optimism.

“Our current warming is happening so quickly that the ocean may behave differently than it does when it’s been warm for a long time, as was the case in the Pliocene,” Farmer said, also noting modern threats such as ocean acidification and overfishing. Still, he added: “It’s good news that the nutrient supply to the eastern Pacific food web will be maintained in a warmer ocean.”

Looking ahead, the team plans to apply their “detective toolkit” to other parts of the ocean.

“We’re looking at a changing system,” Rafter said. “What’s clear from this study is that the system is more complicated than we previously thought.”

Much of the research for the study was conducted while Rafter and Farmer were postdocs at Princeton in the lab of Daniel Sigman, the paper’s senior author.

Foraminifera under a micrscope.

Preparing samples for the foram study.

Credit

Kaitlin Prince, UMass Boston

 

About the University of South Florida

The University of South Florida is a top-ranked research university serving approximately 50,000 students from across the globe at campuses in Tampa, St. Petersburg, Sarasota-Manatee and USF Health. In 2025, U.S. News & World Report recognized USF with its highest overall ranking in university history, as a top 50 public university for the seventh consecutive year and as one of the top 15 best values among all public universities in the nation.  U.S. News also ranks the USF Health Morsani College of Medicine as the No. 1 medical school in Florida and in the highest tier nationwide. USF is a member of the Association of American Universities (AAU), a group that includes only the top 3% of universities in the U.S. With an all-time high of $738 million in research funding in 2024 and as a top 20 public university for producing U.S. patents, USF uses innovation to transform lives and shape a better future. The university generates an annual economic impact of more than $6 billion.  USF’s Division I athletics teams compete in the American Conference. Learn more at www.usf.edu..

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Journal

Science

Method of Research

Experimental study

Subject of Research

Animal tissue samples

Article Title

Persistent eastern equatorial Pacific Ocean upwelling since the warm Pliocene

Article Publication Date

2-Oct-2025

 

Rice membrane extracts lithium from brines with greater speed, less waste

Rice University

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Qilin Li (second from left) and Jun Lou (third from left) are co-corresponding authors on a study published in Nature Communications.

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Credit: Photo by Jorge Vidal/Rice University

HOUSTON – (Oct. 2, 2025) – A team of researchers at Rice University has developed a new membrane that selectively filters out lithium from brines, offering a faster, cleaner way to produce the element at the heart of nearly every rechargeable battery.

According to a study published in Nature Communications, the new membrane achieved one of the highest selectivities for lithium among similar membranes while using considerably less energy. The membrane design can be adapted to target the recovery of other valuable minerals, such as cobalt and nickel, and plugs into existing industrial setups. Tests of the material’s performance and durability indicate it is prime for large-scale synthesis.

Most of the world’s lithium is extracted from saltwater deposits, or brines, which involves sprawling evaporation ponds and extensive chemical treatments. The process is slow, inefficient and environmentally costly.

“The most widely used large-scale lithium extraction method today requires massive evaporation ponds and chemical precipitation,” said Qilin Li, the Karl F. Hasselman Professor of Civil and Environmental Engineering and co-director of Rice’s Nanotechnology Enabled Water Treatment (NEWT) Center. “The process can take over a year to reach the target concentration and has fairly low lithium recovery rates. It also uses a lot of water, often in places that already experience water scarcity, and produces considerable amounts of chemical waste.”

The new membrane offers an alternative way of extracting the lithium via electrodialysis: When an electrical current is applied, lithium ions pass through the membrane, while far more abundant elements like sodium, calcium and magnesium remain behind.

“Typically when you apply an electrical field, all the positively charged ions will transport across the cation exchange membrane,” Li said. “Lithium is actually a minor component in brine, but our membrane allows primarily lithium to transport across. Other ions stay behind.”

That selectivity makes the process both more efficient and less energy-intensive than standard industrial electrodialysis, which is typically used for desalination and wastewater treatment. The team achieved this by embedding nanoparticles of lithium titanium oxide (LTO) into the membrane, taking advantage of LTO’s crystal structure, which is just the right size for lithium ions to move through.

The challenge in utilizing LTO or other lithium ion sieves in membranes is the poor compatibility of the inorganic ion sieves with the polymeric membrane matrix, which often leads to defects in the membranes, undermining performance. To overcome this limitation, the Rice team grafted the LTO with amine groups, which made it possible to mix them evenly into a plasticlike layer called polyamide, creating a strong, defect-free “skin” for the membrane.

“This project builds on our work through the NEWT Center, so it draws on 10 years of research on nanomaterials and nanotechnology,” said Li, who is one of the leaders of the Rice WaTER (Water Technologies Entrepreneurship and Research) Institute. “We have learned how to incorporate nanomaterials into membranes and how to make nanocomposite membranes that fulfill a desired set of functions.”

Each of the membrane’s three layers can be independently optimized, making it a good platform for other applications such as the selective extraction of cobalt or nickel.

“Our goal was to develop a material that can extract lithium with minimum environmental impact,” Li said. “The smart design principles we used to develop the membrane architecture have ensured it can be adapted to help recover many other valuable resources from various waste streams.”

“One of the important features of our membranes is their potential to be produced at scale, which could pave the way for their use in industrial settings,” said Jun Lou, the Karl F. Hasselmann Professor of Materials Science and Nanoengineering.

The researchers tested the new membrane in an electrodialysis system and used computer simulations to zoom in and see how it works at the atomic level. The membrane proved strong and durable, maintaining its performance and withstanding degradation even after two weeks’ use.

Major contributors on the study included Rice alumni Yuren Feng and Xiaochuan Huang as well as Yifan Zhu, a postdoctoral researcher in the Lou lab.

The research was supported by the National Science Foundation (1449500, 1338099), the U.S. Department of Interior (R23AC00442) and the Center for Research Computing at Rice.

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This news release can be found online at news.rice.edu.

Follow Rice News and Media Relations via Twitter @RiceUNews.

Peer-reviewed paper:

A rationally designed scalable thin film nanocomposite cation exchange membrane for precise lithium extraction | Nature Communications | DOI: 10.1038/s41467-025-63660-3

Authors: Yuren Feng, Yifan Zhu, Weiqiang Chen, Xiaochuan Huang, Xintong Weng, Matthew Meyer, Tsai-Hsuan Chen, Yiming Liu, Ze He, Chia-Hung Hou, Kuichang Zuo, Ngai Yin Yip, Kai Gong, Jun Lou and Qilin Li

https://doi.org/10.1038/s41467-025-63660-3

Access associated media files:

https://rice.box.com/s/dk308tizr0y607u93cydfhqb8p3epxm2
(Photos by Jorge Vidal/Rice University)

About Rice:

Located on a 300-acre forested campus in Houston, Texas, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of architecture, business, continuing studies, engineering and computing, humanities, music, natural sciences and social sciences and is home to the Baker Institute for Public Policy. Internationally, the university maintains the Rice Global Paris Center, a hub for innovative collaboration, research and inspired teaching located in the heart of Paris. With 4,776 undergraduates and 4,104 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 7 for best-run colleges by the Princeton Review. Rice is also rated as a best value among private universities by the Wall Street Journal and is included on Forbes’ exclusive list of “New Ivies.”

 

Custom electrodialysis setup: When an electrical current is applied, lithium ions pass through the membrane, while far more abundant elements like sodium, calcium and magnesium remain behind.

 

The researchers embedded nanoparticles of lithium titanium oxide (LTO) into the membrane, taking advantage of LTO’s crystal structure, which is just the right size for lithium ions to move through.

Credit

Photos by Jorge Vidal/Rice UniversityJournal

Nature Communications

DOI

10.1038/s41467-025-63660-3 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

A rationally designed scalable thin film nanocomposite cation exchange membrane for precise lithium extraction

 

Countries with highest reported levels of hearing loss have lowest use of hearing aids

Men more likely than women to report difficulties, although gender divide narrows with age

BMJ Group

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Countries with the highest reported levels of hearing loss also have the lowest reported use of hearing aids, finds international research published in the open access journal BMJ Global Health.

And men are generally more likely than women to report difficulties with their hearing, although this gender divide narrows with age, the findings show.

An estimated 1.57 billion people—equivalent to 1 in 5 of the world’s population—had hearing loss in 2019. And it’s predicted that it will affect 2.45 billion people by 2050, say the researchers.

Hearing loss is associated with an array of problems in adults. These include depression, loneliness, social isolation, falls and fall-related injuries, postoperative complications, cardiovascular disease, cognitive decline and even death, they point out.

But current accurate measurements of hearing loss are limited by a lack of audiology service provision and the expense of collecting hearing test data, they point out.

To strengthen the evidence base, they analysed self-reported hearing loss and hearing aid use from 8 nationally representative long term studies, representing 28 countries for the period 2001–2021.

These studies were: the Brazilian Longitudinal Study of Ageing (ELSI-Brazil, 2016–20); the China Health and Retirement Longitudinal Study (CHARLS, 2011–18); the Costa Rican Longevity and Healthy Ageing Study (CRELES, 2005–09); the Mexican Health and Ageing Study (MHAS, 2001–21); the South African National Income Dynamics Study (NIDS, 2008–17); the Korean Longitudinal Study of Ageing (KLoSA, 2006–20); the Health and Retirement Study from the USA (HRS, 2002–20); and the Survey of Health, Ageing and Retirement in Europe (SHARE, 2004–15).

Each study collected extensive data on the demographic, socioeconomic, behavioural and health characteristics of their adult participants, most of whom were in their 60s. 

Hearing ability was derived from participants reporting whether they used a hearing aid, and how they rated their own hearing, from excellent to poor. The researchers combined these responses to define hearing loss if respondents reported fair or poor hearing, or hearing aid use. 

The prevalence of hearing loss varied widely, with the highest reported prevalence in China (65%), and the lowest in South Africa (16.5%). 

The four countries with the greatest reported prevalence of hearing loss—China, South Korea, Mexico, and Brazil—also had the lowest levels of hearing aid use, ranging from 1%  of those with reported hearing loss in China to 6% in Brazil. 

At the other end of the scale, adults with hearing loss in Northern Europe, the USA, and Western Europe were most likely to report using a hearing aid, ranging from 24% in Western Europe to 39% in Northern Europe.

The responses show that the likelihood of hearing loss increased with age in all countries.

Hearing loss at the oldest ages was reported least in Costa Rica and South Africa, where prevalence barely rose above 40% at ages 85+. But over 50% of 50-54 year-olds in China reported hearing loss, with 80% doing so at the oldest ages. 

With the exceptions of China, South Korea, and South Africa, men were significantly more likely than women to report hearing loss at nearly all ages.

But there were international differences in hearing aid use by age and gender. In the regions with the highest use—Northern Europe, USA, Western Europe—this increased linearly in tandem with age. 

In Northern Europe, for example, around 13% of 50-54 year old men with hearing loss wore hearing aids, compared with 74% at ages 85+. Use also rose in tandem with increasing age in other parts of Europe, Brazil, and South Korea, although overall levels were low, even at the oldest ages. 

In South Africa, the age pattern was reversed. Both older men and older women were less likely to report hearing aid use than their younger counterparts.

Gender differences in hearing loss were greatest in the USA, where men were 1.6 times more likely to report this than women. Men in South Africa, China, and South Korea were also 1.5 times more likely to report wearing a hearing aid, although overall use in China and South Korea was extremely low. 

Women in Brazil were more likely than men to wear hearing aids, while gender differences were small or non-existent in Northern and Southern Europe, Costa Rica, Mexico and Western Europe.

In regions with the largest gender differences, men below the age of 70 were up to twice as likely to report hearing loss as women, but this divide narrowed with age. On the other hand, there were little to no gender differences in hearing loss at any age in China, South Africa, and South Korea.

In areas with high hearing aid use (Northern Europe, USA, Western Europe and Israel), younger women were more likely to wear them than younger men. In mid-use regions (Costa Rica, Central and Eastern Europe and Southern Europe), gender differences were inconsistent across age categories. 

And although use was low or practically non-existent in South Africa, South Korea, and China, men of nearly all ages in these countries were consistently and significantly more likely to wear them than women.

The researchers acknowledge various limitations to their findings, including the reliance on self-reported measures of hearing loss and hearing aid use rather than objective measurements. And while the study encompassed a diverse number of countries, it was limited to those classified as upper-middle to high-income.

Nevertheless, they suggest that: “the wide range in self-reported hearing loss, from 17% in South Africa to 65% in China, suggests complex interactions between a country’s structural factors, like medical and educational systems, and a host of socio-cultural elements, such as beliefs around stigma, disability, and gender norms.” 

They add: “The role of structural systems may be especially pertinent for [low and middle income countries], whose health systems are still developing and where specialty services, such as audiology, have only been recently established.”

But pinpointing the correlation between access and uptake at the international level is complicated, they point out. 

“Even in countries with complete or near-complete insurance coverage (eg, Western Europe, Northern Europe), hearing aid uptake remains well below 100%, suggesting that financial access can only tell some of the story,” they write.

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Journal

BMJ Global Health

DOI

10.1136/bmjgh-2024-017655 

Method of Research

Observational study

Subject of Research

People

Article Title

Gender differences in self-reported hearing loss and hearing aid use: a cross-national comparison

Article Publication Date

2-Oct-2025