Bacteria form 'herds' to survive predators, offering fresh insight into Earth's carbon cycle 

Researchers at Queen Mary University of London have discovered that tiny photosynthetic bacteria band together into protective "herds" when attacked by predators – a survival strategy that could also influence how carbon is stored in the world's waters

Queen Mary University of London

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Credits belong to the ISME journal

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Credit: Credits belong to the ISME journal

Bacteria form 'herds' to survive predators, offering fresh insight into Earth's carbon cycle 

Researchers at Queen Mary University of London have discovered that tiny photosynthetic bacteria band together into protective "herds" when attacked by predators – a survival strategy that could also influence how carbon is stored in the world's waters. 

Published in The ISME Journal, the study reveals for the first time that cyanobacteria – microscopic organisms responsible for producing a significant proportion of the Earth's oxygen  – rapidly cluster into dense groups when they detect the presence of foreign bacteria. These defensive clumps, known as flocs, shield inner cells from attack, much like a herd of wildebeest protects its most vulnerable members from predators. 

The research helps explain a long-standing biological mystery: why cyanobacteria invest energy in forming flocs despite the apparent cost to their growth. The findings suggest the behaviour is an evolved defense mechanism that could have implications extending from microbial ecology to the global carbon cycle. 

The research team studied interactions between the cyanobacterium Synechocystis and Pseudomonas aeruginosa, a bacterium commonly found in soil and freshwater. They found that the predator uses microscopic molecular "weapons" to puncture and kill individual cyanobacterial cells, consuming the nutrients they release. In response, the cyanobacteria rapidly aggregate into dense flocs surrounded by a protective layer of extracellular slime, making it much harder for predators to reach the cells inside.  

"It was very exciting to see this project leading to a new explanation for why cyanobacteria form flocs. We saw that these tiny cells quickly come together into protective clumps when predators are present, showing that this is a coordinated survival strategy, not just a passive response. This work gives a new way to think about how this can affect the biological carbon pump in nature. In simple terms, it is like how many living organisms stay in groups for protection, cyanobacteria also cluster together to reduce the risk of being attacked." Says Dr Shylaja Mohandass, first author of the study. 

The team found that predators grew more successfully when attacking mutant cyanobacteria that could not form these protective clumps, providing strong evidence that flocculation is an effective defense against bacterial predation. The researchers also discovered that the response is triggered simply by contact with foreign bacteria, suggesting cyanobacteria can distinguish between "self" and "non-self" at the microscopic level.  

Beyond revealing an unseen microbial battle, the findings may also help scientists better understand one of the planet's most important natural climate processes. 

When cyanobacteria form dense flocs, they are more likely to sink, carrying carbon absorbed through photosynthesis into deeper waters where it can remain stored for long periods. This process, known as the “biological carbon pump”, plays a crucial role in regulating atmospheric carbon dioxide. 

Professor Conrad Mullineaux from Queen Mary University of London, said: 

"It was fascinating to look in the microscope and see a complex predator-prey relationship unfolding on such a tiny scale. It reminds me of lions and wildebeest on the Serengeti - you can see P. aeruginosa catching and lysing those cyanobacteria that were a bit too slow to get into the herd".  

The discovery also raises an intriguing possibility: bacteria previously thought to reduce carbon storage by consuming organic matter may, under some circumstances, actually help increase carbon burial by triggering floc formation in photosynthetic microbes. 

"It's so interesting to see that bacterial predation may actually be a crucial factor in the control of environmental carbon levels, and is an exciting new avenue for the field to explore." added Dr Alice Collins, from Imperial College London, who contributed her Pseudomonas expertise to the study. 

Cyanobacteria transformed the biosphere about 2.5 billion years ago, and today they remain hugely abundant in lakes and oceans, producing over 20% of the world’s oxygen. This study is indispensable as it reveals that microscopic bacteria work together to defend themselves from predators—and that this behaviour could have unexpected consequences for how our planet stores carbon. 

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Journal

Microbial Ecology

DOI

10.1093/ismejo/wrag169/8719643 

 

Unlocking the synergistic promoter role of phosphorus in evolving NiFe phosphides for enhanced water oxidation

Shanghai Jiao Tong University Journal Center

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• Phosphorus drives NiFeP’s reconstruction into active NiFe (oxy)hydroxide, suppresses Fe dissolution, and modulates Ni’s electronic structure via residual PO43−.
• PO43− and Fe synergistically act as a redox buffer, preventing Ni over-oxidation, narrowing the bandgap, and stabilizing key oxygen evolution reaction intermediates to lower the energy barrier.
• The restructured catalyst achieves a low overpotential of 225 mV at 10 mA cm−2 and maintains stable operation in alkaline media for over 100 h at current densities up to 500 mA cm−2.

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Credit: Ningning Shi, Mingcheng Gao, M. Maneesha, C. S. Praveen*, Panpan Liu, Shengnan Yue, Wangjing Xie, Dechao Chen, Yu Tang, Yuanqing Wang*, Hua Fan, Xing Huang*.

As the global economy's thirst for energy depletes traditional fossil fuels and intensifies environmental crises, the transition to clean, dispatchable hydrogen via electrochemical water splitting has become an urgent imperative. Yet the anodic oxygen evolution reaction (OER)—a sluggish, four-electron process—remains the primary bottleneck throttling overall efficiency. While noble-metal oxides such as RuO2 and IrO2 deliver acceptable activity, their scarcity and exorbitant cost render large-scale deployment economically untenable. Earth-abundant NiFe-based catalysts have long been pursued as alternatives, but the atomistic mechanisms by which anionic species like phosphorus direct structural evolution and catalytic enhancement have remained elusive. Now, researchers from Fuzhou University, Shanghai University, and Cochin University of Science and Technology, led by Professor Xing Huang, Professor Yuanqing Wang, and Professor C.S. Praveen, have presented a breakthrough study that fundamentally redefines the role of phosphorus in NiFe phosphide electrocatalysts.

Why This Catalyst Matters

Conventional wisdom has largely treated phosphorus in metal phosphides as a sacrificial template—leachable during anodic polarization to leave behind active metal (oxy)hydroxides—or as a passive electronic modifier. This work breaks that paradigm by demonstrating that phosphorus is far more than a disposable scaffolding. Through systematic identical-location transmission electron microscopy (IL-TEM), spectroscopy, and electrochemical analysis, the team reveals that phosphorus actively orchestrates a triple function: it accelerates the reconstruction of NiFeP into defect-rich NiFe (oxy)hydroxide nanosheets, suppresses the dissolution of Fe ions that plagues conventional NiFe precursors, and—most critically—leaves behind residual phosphate oxyanions (PO43-) that synergize with Fe to serve as an intrinsic redox buffer. This dual-anion synergy modulates the electronic structure of Ni, preventing over-oxidization while simultaneously stabilizing key reaction intermediates—a mechanism previously undocumented in the literature.

Innovative Design and Mechanism

The catalyst is synthesized through a multi-step engineering strategy: nickel precursor prisms are first fabricated via PVP-assisted reflux, then chemically transformed into hollow NiFe cyanide frameworks through coordination with [Fe(CN)6]3-, and finally phosphidated at 350 °C under argon to yield hollow NiFeP prisms composed of crystalline NixFe2-xP domains enveloped by amorphous phases containing Ni, Fe, O, P, and K. Under anodic OER conditions, IL-TEM captures the dynamic reconstruction in real time: the hollow prisms progressively evolve into ultrathin nanosheets over 120 minutes, with phosphorus largely dissolving while the Ni/Fe ratio remains preserved.

Density functional theory calculations unveil the synergistic promoter role of residual PO43-. In the reconstructed NiFe (oxy)hydroxide lattice, Fe initially lowers the average oxidation state of Ni, while intercalated PO43- acts as an effective redox buffer—maintaining a higher proton concentration across the operational potential window and preventing Ni from becoming over-oxidized. Bader charge analysis confirms that PO43- withdraws electron density from the Ni–O lattice, buffering Ni oxidation states while stabilizing oxygenated adsorbates. Hybrid functional calculations further reveal that PO43- and Fe cooperatively narrow the bandgap from ~0.85 eV to ~0.15 eV, dramatically enhancing electronic conductivity and charge delocalization. Free-energy profiles demonstrate that this synergy compresses the energy span among *OH, *O, and *OOH intermediates, reducing the theoretical overpotential by 0.38 V relative to pristine NiOOH.

Outstanding Performance

The reconstructed NiFeP catalyst (NiFeP-A) delivers exceptional OER activity in alkaline media, achieving a low overpotential of merely 225 mV at 10 mA cm-2—outperforming pre-NiFe (344 mV), NiFeO (300 mV), Ni2P (296 mV), and even commercial RuO2 (276 mV). The Tafel slope of 31 mV dec-1 indicates superior reaction kinetics, while the charge-transfer resistance of 1.36 Ω confirms remarkably fast electron transfer. The catalyst exhibits the highest intrinsic activity among all samples, with a specific activity of 23.63 mA cm-2, a mass activity of 314.2 A g-1, and a turnover frequency of 0.14 s-1 at 1.53 V vs. RHE. Durability tests demonstrate robust stability over 100 h at current densities of 10, 100, and even 500 mA cm-2 without significant degradation. When paired with commercial Pt/C in a two-electrode configuration for overall water splitting, the system requires only 1.51 V to reach 10 mA cm-2—superior to the commercial Pt/C || RuO2 benchmark (1.56 V)—and maintains stable operation for over 100 h.

Applications and Future Outlook

This work transcends the conventional pre-catalyst narrative and establishes phosphorus as an active, synergistic component in electrocatalytic water oxidation. By unlocking the triple role of phosphorus—structural director, dissolution suppressor, and electronic modulator—the study provides a rational blueprint for designing anion-engineered, earth-abundant electrocatalysts. The insights into redox-buffering mechanisms and dynamic structure–performance relationships pave promising avenues for next-generation alkaline electrolyzers, offering a viable pathway toward cost-effective, high-efficiency green hydrogen production at industrial scales.

Stay tuned for more groundbreaking research from this collaborative team at Fuzhou University, Shanghai University, and Cochin University of Science and Technology!

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Journal

Nano-Micro Letters

DOI

10.1007/s40820-026-02238-0 

Method of Research

News article

Article Title

Unlocking the Synergistic Promoter Role of Phosphorus in Evolving NiFe Phosphides for Enhanced Water Oxidation

 

Researchers discover a mechanism for salt tolerance in plants

New study: A particular chemical mark in the “histone code” is responsible for adaptation to salt stress

University of Münster

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Due to artificial irrigation and rising temperatures, the concentration of salts (including sodium chloride, or ‘table salt’) is increasing in soils worldwide. This is not only an environmental problem, but also a challenge for agriculture. For example, increased salinity can disrupt the water balance of most plants (known as glycophytes) or even lead to their death, including our crops. Only in coastal regions do plants exist that have developed special salt-tolerance mechanisms. Such plants are known as halophytes. Yet glycophytes are also able to protect themselves against higher salt concentrations and drought to a certain extent. In order to develop resistant crops, it is necessary to understand the various molecular regulatory mechanisms that play a role in response to salt stress. A team led by Professor Iris Finkemeier from the Institute of Plant Biology and Biotechnology at the University of Münster (Germany) and Professor Motoaki Seki from the RIKEN research institute (Japan) has now discovered a previously unknown mechanism.

The researchers investigated the “histone code” and its role in adapting to salt stress in thale cress (Arabidopsis thaliana). Histones are proteins within the genome. They do not carry genetic information but regulate, along with other factors, whether and to what extent information in the DNA is used to produce proteins. This epigenetic control is based on chemical modifications to histones, known as histone marks, which influence the interaction between histones, DNA and regulatory proteins. The researchers discovered a histone mark that is essential for the plant's stress response.

In thale cress, the enzyme “HDA19” plays an important role in regulating plant development, metabolism and stress response. The team demonstrated that this enzyme is responsible for removing the newly discovered histone mark, thereby influencing how the plant copes with high salt content. Plants lacking the enzyme are significantly more tolerant to saline soils. In these plants, proteins that are also found in dry seeds (“late embryogenesis abundant (LEA) proteins”) are produced in greater quantities. These proteins help plants adapt to drought. However, these plants grow slightly slower and produce reduced seed yield. These seedlings are well suited for deciphering the molecular basis of control. In addition to various molecular genetic methods, the team used high-resolution mass spectrometry and identified proteins regulated by HDA19.

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2534315123 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Publication Date

13-Jul-2026

 

How an influx of salt may affect microbial ecosystems

MIT scientists find that as sea levels rise and saltwater seeps into freshwater, stressed aquatic populations may retain overall growth even as diversity declines

Massachusetts Institute of Technology

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CAMBRIDGE, MA -- As sea levels rise due to climate change, encroaching sea water will likely make freshwater environments saltier. In a new study, MIT researchers have shown how that increase in salinity might affect microbial ecosystems found in environments such as rivers and estuaries.

These microbial communities play important roles in the carbon cycle, and they also help to decompose organic matter such as algae. The MIT team found that when salt levels rise, these populations lose diversity as faster-growing strains tend to take over the community, but they maintain their overall growth rate.

“At higher salinity, you lose diversity, which is ultimately not good for an ecosystem. But what we were surprised at is that in the meantime, even though diversity decreases, the growth of the community and the production of biomass is not impacted that much,” says Jana Huisman, an MIT postdoc and the lead author of the new study.

Jeff Gore, an MIT professor of physics, is the senior author of the paper, which appears today in Nature Microbiology. Martina Dal Bello, a former MIT postdoc who is now an assistant professor of ecology and evolutionary biology at Yale University, is also an author of the study.

Rising salt levels

Microbes that live in aquatic environments are typically adapted to thrive in fresh or salt water, or somewhere in between. Microbes that live in higher salt environments have cell walls that are optimized to resist osmotic pressure, and membrane transporters that can pump sodium ions out of the cell.

Freshwater lakes and rivers have salt concentrations around 1 gram of salt per liter of water (g/L), while oceans can reach 35 g/L. As the climate warms and sea levels rise, those oceanic waters may seep into estuaries and other inland bodies of water, increasing their salinity.

“When you think about climate change, you can think about rising temperatures, which is very common, but also a lot of other environmental stresses are going to increase,” Huisman says.

Huisman is from the Netherlands, a country with an extensive coastal delta, and she was interested in exploring how changes in salinity might affect microbial ecosystems in those aquatic habitats. The new study builds on previous work from Gore’s lab showing that higher seawater temperatures tend to favor slower-growing bacteria.

For the new study, the researchers took samples from three aquatic environments with varying salinity: the Charles River near the MIT Sailing Pavilion (4 g/L), Boston Harbor (30 g/L), and a beach in Nahant, Massachusetts (35 g/L). Each community contained hundreds of species of microbes. The researchers then grew each population in three environments of varying salinity — 16, 31, or 46 g/L.

Over two weeks, the researchers measured the communities’ growth rates and found that overall, each community maintained the same growth rate at each of the three concentrations. However, in the communities exposed to higher salt environments, the overall composition became less diverse. Further studies showed that these communities tended to be dominated by faster-growing species.

“We saw that those communities that had been propagated at higher salinity had reached a markedly different composition than the ones that lower salinity,” Huisman says.

Natural ecosystems

To explore whether their lab results might correspond to what happens in natural ecosystems, the researchers analyzed publicly available genomic data from microbes found in different aquatic ecosystems, including the Chesapeake Bay, the Gulf of Mexico, and the Baltic Sea.

For this portion of the study, the researchers focused on a genetic marker called the 16S rRNA gene copy number, which can be used as a proxy for the maximum growth rate that a species can attain. The more copies of this gene that a species has, the faster its intrinsic growth rate.

The researchers found that in these natural communities, environments with higher salinity also tended to be dominated by faster-growing species.

“When we first saw that, it was very exciting — that, indeed, what we found in the lab seems to also be represented in data from natural communities, sampled across a range of different environments,” Huisman says. “You see the same signatures in such data, and that’s highly suggestive that what we found in the lab might also be true in natural environments.”

One potential drawback to this loss of diversity is a reduction in microbial populations’ ability to withstand other types of environmental stress, the researchers say.

In this study, the researchers did not investigate the functions of the individual bacterial strains that ended up becoming more prevalent. Some of them may play beneficial roles, but it’s also possible that some of them might be pathogenic strains.

“Whether you want faster-growing species to take over or not might also be related to what the identity of those species is. That is something that I’m interested in looking at in the future,” Huisman says.

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The research was funded by a Human Frontier Science Program Fellowship and a Schmidt Science Polymath Award.

 

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Journal

Nature Microbiology

DOI

10.1038/s41564-026-02422-3 

Article Title

Predictable shifts in microbial species composition lead to community-wide robustness to environmental stress

Article Publication Date

17-Jul-2026

 

Hanyang University study finds carbon-based pricing encourages greener tourist intentions

Surcharges tied to resource use proved more effective than discounts, while itemized environmental fees boosted conservation intentions

Hanyang University Research Strategy Planning Team

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A new study suggests that linking hotel charges to guests’ environmental impact could encourage stronger intentions to behave more sustainably. Researchers found that travelers reported stronger intentions to conserve energy and water when resource use was tied to pricing, particularly when environmental costs were presented as visible surcharges or itemized charges. The findings indicate that market-based incentives may help reduce tourism-related emissions while remaining compatible with consumer choice and business profitability.

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Credit: Hanyang University and Professor Hakseung Shin

Hotels have long encouraged guests to reuse towels, limit linen changes, and conserve energy. Yet tourism remains a significant source of carbon emissions, and voluntary sustainability programs often struggle to achieve lasting behavior change. New research suggests a different approach may be more effective: connecting the environmental impact of a stay directly to what travelers pay.

Professor Hakseung Shin of the School of Tourism and colleagues from Hanyang University found that tourists were more likely to report intentions to adopt environmentally friendly behaviors when accommodation prices were linked to their resource consumption. The study showed that carbon-based pricing increased intentions to conserve energy and water, especially when environmental costs appeared as separate charges and when excessive consumption triggered a surcharge rather than a reward.

This paper was made available online on May 22, 2026, and was published in Volume 119 of the journal Annals of Tourism Research on July 01, 2026.

Prof. Shin said, “Difficult sustainability challenges cannot be solved solely through moral appeals or regulations. Instead, they should be addressed through green capitalism—environmental policies that align ecological goals with market incentives.”

The team investigated whether carbon-linked pricing could encourage more sustainable choices among travelers. Under such systems, guests pay according to their resource consumption and associated environmental impact, with charges tied to resource use such as electricity, water, heating, cooling, or linen services. The team conducted three experiments using realistic hotel and short-term rental booking scenarios, testing how different pricing structures influenced participants’ intentions to conserve resources during a stay.

Across the studies, carbon-based pricing consistently increased pro-environmental behavioral intentions. Participants who knew that wasteful consumption could increase their costs reported stronger intentions to conserve resources. Likewise, incentives in discount pricing produced conservation intentions comparable to surcharge pricing. These findings provide some of the first experimental evidence that market-based environmental pricing can influence tourism-related sustainability decisions.

The study also revealed that how environmental costs are presented matters. Participants responded more strongly when higher resource consumption resulted in an additional charge than when lower consumption earned an equivalent discount. Separately itemized environmental charges also generated stronger responses than costs bundled into a single total price, suggesting that making environmental costs visible can increase their influence on consumer decision-making. “This research can be applied in hotels, Airbnb properties, and tourism platforms through carbon-based pricing systems that reward low-impact behavior or charge for excessive resource use,” said Prof. Shin.

The team argues that such approaches could become increasingly relevant as smart technologies make it easier to track individual resource consumption. Carbon-based pricing could integrate environmental considerations into everyday travel decisions. Looking ahead, the researchers believe these systems may help support the transition to a lower-carbon tourism sector.

“Over the next 5–10 years, advances in smart technologies and carbon tracking may make personalized carbon pricing commonplace in tourism,” stated Prof. Shin. The researchers note that the study used hypothetical booking scenarios and measured behavioral intentions rather than actual behavior. Future studies will be needed to determine whether these effects translate to real-world tourism settings.

 

Reference
DOI: https://doi.org/10.1016/j.annals.2026.104209

 

About Hanyang University
Hanyang University traces its roots back to 1939 when the Dong-A Engineering Institute was established. By 1948, the institute had transformed into the nation’s first private university, evolving into Hanyang University in 1959. At its core, Hanyang University upholds the Founding Philosophy of “Love in Deed and Truth,” and its mission is to provide practical education and professional training to future experts and leaders. With a rich history spanning nearly a century, Hanyang University continues to uphold its core values while adapting to the evolving landscape of education and research, both domestically and internationally.

Website: https://www.hanyang.ac.kr/web/eng

 

About the author
Professor Hakseung Shin is a faculty member in the School of Tourism at Hanyang University. He earned his B.A. and M.A. from Hanyang University and a Ph.D. in Business from Virginia Tech. His research focuses on tourism ecosystems and technology- and ESG-driven tourism innovation. Recognized among Elsevier’s Top 2% Scientists in 2024 and 2025, he contributes to tourism research, industry, and policy development.

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Journal

Annals of Tourism Research

DOI

10.1016/j.annals.2026.104209 

Method of Research

Experimental study

Subject of Research

People

Article Title

Paying for carbon: CO₂-based pricing mechanisms and pro-environmental behavior in tourism

Article Publication Date

1-Jul-2026