The research, a collaboration between the Wyss Institute for Biologically Inspired Engineering at Harvard University, Harvard Medical School’s Department of Systems Biology, and the Stanford Doerr School of Sustainability, was led by Wyss Founding Core Faculty member Pamela Silver and Associate Faculty member Michael Springer. First author and chemical engineer Neil Dalvie, who spearheaded the project as a postdoctoral fellow in Silver’s laboratory, and his colleagues genetically engineered Alteromonas macleodii, a bacterium widespread in marine environments, to produce far greater quantities of molecules called siderophores. These compounds are the bacterial world’s iron-scavenging tools, and it turns out they are also remarkably effective at stripping iron from the surfaces of silicate minerals. In customized bioreactors flushed with a continuous flow of seawater, the engineered microbe accelerated the weathering of the silicate mineral olivine by 2.6-fold, measurably increasing the amount of atmospheric carbon dioxide drawn into the water. The findings were published in Nature Biotechnology.

To understand why bacteria can speed up rock dissolution, it helps to look closely at what actually happens on a weathering mineral surface. When olivine and similar silicates dissolve, they release magnesium, iron, and silicate, and the chemistry of that dissolution simultaneously traps atmospheric carbon dioxide in the surrounding water as bicarbonate. But the released iron presents a problem: exposed to oxygen in the atmosphere, it is not soluble and instead precipitates as rust, coating the mineral surface and slowing the entire weathering process to a crawl. Bacteria that produce siderophores can capture, solubilize, and import that oxidized iron to satisfy their own nutritional needs. In doing so, they effectively de-rust the mineral surface, exposing fresh reactive material to seawater and allowing dissolution to continue. It is a subtle biological intervention with outsized geochemical consequences, and it is precisely this natural mechanism the Harvard team set out to amplify.

The first obstacle the researchers encountered was regulatory rather than chemical. Using custom bioreactors to dissect when natural bacteria produce siderophores, they discovered that even a small amount of iron-containing mineral completely shut down siderophore production. Wild bacteria, it seems, are thrifty: once they have accumulated enough iron to support growth, they stop investing energy in making the scavenging molecules altogether. That built-in thriftiness is a disaster for anyone hoping to harness siderophores for industrial-scale carbon removal, because the whole point is to have the bacteria continuously attack mineral surfaces regardless of how much iron is already available. Once wild bacteria have enough iron to grow, they stop making siderophores completely, Dalvie explained. To enable enhanced weathering at scale, the team engineered A. macleodii to always produce siderophores, essentially decoupling production from environmental iron levels and converting a self-regulating survival mechanism into a relentless industrial workhorse.

Engineering the microbes took roughly a month, but the far harder task was proving that the modification actually translated into faster weathering and greater carbon uptake. For that validation, Dalvie teamed up with Amogh Jalihal, a postdoctoral fellow in Springer’s group at the Wyss Institute and Harvard Medical School. The two researchers concluded that the most rigorous measurement would be made at steady state, with seawater and bacteria continuously flowing over the minerals rather than sitting in batch cultures where conditions drift unpredictably. Fortunately, Springer’s group had recently acquired an entire room of eVOLVER bioreactors, small-scale devices originally designed by Ahmad Khalil, another Wyss Associate Faculty member and professor at Harvard University. The eVOLVER platform, with its modular, automated control of growth conditions, proved ideal for the small-scale studies that would establish whether the engineered strain genuinely outperformed its wild-type ancestor on real rock.

Those early experiments showed promise, and the team escalated to pilot-scale bioreactors loaded with several kilograms of green olivine sand submerged under gallons of raw seawater drawn from Boston Harbor. Working at pilot scale forced the researchers to confront the practical questions that separate laboratory demonstrations from deployable technology: how often cells needed to be added, how they should be fed, and how the system could be kept running continuously. Eventually the team was able to measure actual uptake of 0.5 grams of atmospheric carbon dioxide into the reactors each day, a modest absolute quantity but a compelling proof of principle for a process that could, in principle, be replicated across enormous basins. The result demonstrated that engineered bacteria could survive and function in unprocessed seawater, on unrefined mineral feedstock, under conditions far closer to the open environment than a sterile laboratory flask.

Quantifying the climate value of any proposed carbon removal technology requires more than measuring uptake in a reactor, however. To that end, Dalvie and Jalihal collaborated with Abigail Fitzgibbon, a doctoral student working with Steven Davis, Professor of Earth System Science at the Stanford Doerr School of Sustainability, whose group develops models to quantify the carbon emissions of industrial and agricultural processes and their effects on air quality and human wellbeing. Together the teams carried out a Life Cycle Analysis, an accounting framework that captures all carbon emitted or sequestered by the entire system over time, including its living, geological, and chemical components. The collaboration enabled the researchers to calculate the net carbon balance of their system precisely and to identify which process parameters would be decisive in making the technology efficient at industrial scale. Such analyses are essential for distinguishing genuinely negative-emission technologies from those that merely shuffle carbon from one reservoir to another.

The path from pilot reactor to planetary impact still runs through substantial scale-up work. The team notes that further studies are needed to identify economically viable sources of feedstocks and silicate minerals, since the cost and carbon footprint of mining, crushing, and transporting rock could easily erode the climate benefit if chosen poorly. Intriguingly, the researchers are also investigating whether valuable metals could be extracted from the silicate minerals alongside carbon sequestration, potentially creating a co-product revenue stream that improves the economics of deployment. Dalvie recently received a fellowship from the Burroughs Wellcome Career Awards at the Scientific Interface program, which will fund continued work on microbial siderophore production and mineral processing, providing momentum for the next phase of development.

Springer’s vision for deployment is strikingly pragmatic. The most straightforward way to create environmental impact, he suggested, would be to grow the bacterial strains with adequate food sources in large basins resembling those found at sewage treatment plants, continuously pumping unprocessed seawater in and releasing alkaline seawater back into the ocean, where the bound carbon would be completely harmless and buffered away. Such a design would piggyback on existing industrial infrastructure and established engineering practices, avoiding the need to invent novel containment systems from scratch. Because the carbon ends up as bicarbonate dissolved in seawater, the approach avoids many of the permanence and monitoring concerns that complicate other carbon removal strategies, and the alkalinity released to the ocean may itself help counteract acidification, though the team’s published claims rest on the weathering and carbon uptake results rather than on ocean alkalinity benefits.

Silver framed the work as an embodiment of biologically inspired engineering, demonstrating how synthetic biology can enhance natural climate-regulating processes with potentially positive planetary impact. She and her colleagues believe the strategy is easily applicable and low-risk, and could be implemented in many locations with real-world decarbonization outcomes. Whether engineered bacteria can weather rock fast enough to matter for the global carbon balance remains to be proven at scale, and the jump from half a gram of carbon dioxide per day to gigatonne-relevant removal is enormous. But the study, supported by the Wyss Institute Director’s Fund, the Synthetic Biology Hive at Harvard Medical School, Harvard’s Climate and Sustainability Translational Fund, the Salata Institute for Climate and Sustainability, a Garden Grant from the Homeworld Collective, and a Schmidt Science Fellowship, establishes a credible new entry in the growing portfolio of ocean-based carbon removal approaches. Other authors on the study include Jan-Tobias Böhnke, Mohammed Hijaz, and Quincey Justman. If the numbers scale as hoped, the humble chemistry of rusting iron and dissolving stone, accelerated by reprogrammed microbes, could become one of the more elegant tools in humanity’s decarbonization arsenal.

Subject of Research: Synthetic biology enhancement of marine bacterial siderophore production to accelerate silicate rock weathering for atmospheric carbon dioxide removal

Article Title: Pulling carbon into seawater using engineered bacteria

Article References: Pulling carbon into seawater using engineered bacteria. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: carbon removal, rock weathering, synthetic biology, siderophores, Alteromonas macleodii, olivine, ocean alkalinity, enhanced weathering, climate change, bioreactors, life cycle analysis, marine bacteria

The strategy, described by the authors as a pre-calcination thermomechanical hot-pressing treatment, was integrated into an established hydrothermal synthesis route for carbon-coated lithium iron phosphate, commonly abbreviated LFP/C. In a typical hydrothermal process, the olivine precursor particles are formed in solution, mixed with an organic carbon source such as glucose, and then calcined at high temperature to crystallize the phase and pyrolyze the carbon coating into a conductive shell. The Korean team inserted an additional step between these stages. After the hydrothermal reaction but before the high-temperature sintering, they subjected the amorphous precursor-glucose matrix to uniaxial pressure of 5 megapascals at a temperature of 200 degrees Celsius for 10 minutes. The parameters were deliberately optimized and held fixed to establish reproducibility and to define clear processing boundaries for the technique.

The timing of this mechanical treatment is what makes it scientifically interesting. At 200 degrees Celsius, the precursor material has not yet crystallized into the ordered olivine framework. It exists as a soft, amorphous matrix interspersed with glucose, the organic molecule that will later become the carbon coating. Applying pressure at this stage produces what the researchers describe as localized physical consolidation within that matrix. In practical terms, the pressing bridges void spaces that exist between and within the precursor particles, forcing them into more continuous contact with one another. Because this compaction happens before phase crystallization, the improved particle-to-particle contact is locked in when the material is subsequently fired, rather than being erased by later processing steps.

Why does this matter for battery performance? The answer lies in the concept of charge-transfer resistance, a quantity electrochemists denote as Rct. Every time a lithium ion crosses the interface between the electrode material and the electrolyte, and every time an electron hops between particles in the composite electrode, it encounters resistance. High interfacial resistance manifests as voltage polarization, meaning the cell delivers less voltage than it theoretically should during discharge and requires more voltage than expected during charge. That wasted energy appears as heat and reduces the usable capacity of the battery, particularly at high charge and discharge rates where the demand for rapid ion and electron transport is greatest. Poorly connected particle networks force electrons to take tortuous paths through the carbon additive, and isolated particles may be electronically disconnected altogether, contributing nothing to the cell’s capacity.

When the team compared hot-pressed and conventional unpressed electrodes, the differences were clear. The hot-pressed LFP/C cathode exhibited remarkably minimized voltage polarization and a significantly reduced interfacial charge-transfer resistance relative to the unpressed baseline. The continuous electrical contact networks enforced by the pre-sintering compaction gave electrons shorter, more direct pathways through the electrode, while the bridged void spaces improved the physical intimacy between active material, carbon coating, and conductive additives. The result is an electrode in which a larger fraction of the active material participates effectively in the lithiation and delithiation reactions, and in which the reactions themselves proceed with less energetic penalty at the interface.

The galvanostatic cycling results underscore the practical value of the treatment. Under repeated charge and discharge, the optimized hot-pressed cathode demonstrated robust early-stage transport kinetics and maintained a highly stable discharge capacity of well over 110 milliampere-hours per gram after 100 cycles. For lithium iron phosphate, whose theoretical capacity is approximately 170 milliampere-hours per gram, sustaining capacity above 110 milliampere-hours per gram over a hundred cycles indicates that the electrode retains both its structural integrity and its transport advantages through repeated lithium insertion and extraction. Stability in early cycling is particularly significant because degradation mechanisms such as particle cracking, carbon coating disruption, and interfacial film growth tend to be most aggressive in the initial cycles, when the electrode microstructure is still adapting to the volume changes of lithiation.

The study also carries a broader message about where the next gains in battery materials may come from. Much of the historical progress on lithium iron phosphate has come from chemistry: reducing particle size to shorten lithium diffusion distances, coating particles with carbon to improve conductivity, and doping the lattice with supervalent ions to create charge carriers. The work of Choi, Heo, and their colleagues, supervised by corresponding author Jong-Tae Son, demonstrates that processing engineering, the physical manipulation of the material between chemical synthesis steps, offers a complementary and potentially inexpensive lever. Hot pressing requires no exotic reagents, no rare additives, and no fundamental change to the synthesis chemistry. It is a mechanical step that could, in principle, be incorporated into existing powder processing lines with modest capital investment.

The choice of 200 degrees Celsius, 5 megapascals, and 10 minutes reflects a careful balancing act. The temperature must be high enough to soften the amorphous precursor and the glucose matrix so that particles can deform and consolidate under pressure, but low enough to avoid premature crystallization or carbonization that would fix the microstructure before compaction is complete. The pressure must be sufficient to close voids and enforce contact, yet gentle enough to avoid fracturing particles or damaging the nascent carbon precursor coating. The 10-minute hold keeps the process compatible with industrial throughput. By strictly optimizing and reporting these boundaries, the authors have provided a reproducible recipe that other laboratories can replicate and extend, testing whether different pressures, temperatures, or hold times yield further improvements.

The findings arrive at a moment when lithium iron phosphate is expanding its share of the global battery market. Its cobalt-free chemistry sidesteps the ethical and supply-chain concerns associated with cobalt-based cathodes, and its thermal stability makes it attractive for applications where safety is paramount. Improving its rate capability and interfacial kinetics without raising cost is therefore a goal with enormous economic leverage. Interface engineering of the kind demonstrated here, in which the physical connectivity of the electrode’s internal network is deliberately sculpted before the material reaches its final form, could complement ongoing advances in electrolyte formulation, cell design, and manufacturing scale-up.

For the battery community, the study offers a reminder that the path from powder to performance runs through microstructure. Two electrodes made from chemically identical active material can behave very differently depending on how well their particles touch, how continuous their conductive networks are, and how much resistance ions and electrons encounter at each interface. By pressing the question of connectivity into the synthesis process itself, quite literally, the Korean team has shown that a modest thermomechanical nudge at the right moment can echo through the entire life of a battery cell. As manufacturers search for incremental gains that add up to faster charging, longer range, and cheaper storage, such processing insights into the olivine framework may prove to be among the most practical tools available.

Subject of Research: Hot-pressing treatment of hydrothermally synthesized LiFePO4/C cathodes to reduce charge-transfer resistance in lithium-ion batteries

Article Title: Effect of hot-pressing on charge transfer resistance and electrochemical performance of LiFePO₄ cathodes

Article References: Choi, Y.-H., Heo, G.-W., Kim, J. H., Won, J.-M., Lee, S.-H., Choi, M.-S., Cho, J.-H., Kang, S., & Son, J.-T. (2026). Effect of hot-pressing on charge transfer resistance and electrochemical performance of LiFePO₄ cathodes. Ionics. https://doi.org/10.1007/s11581-026-07522-y

Image Credits: AI Generated

DOI: 10.1007/s11581-026-07522-y

Keywords: LiFePO4, cathode, hot pressing, charge-transfer resistance, hydrothermal synthesis, olivine, lithium-ion battery, carbon coating, voltage polarization, electrochemical performance, interface engineering, sintering

A new study led by Candice Bedford, a research scientist in Purdue University’s Department of Earth, Atmospheric, and Planetary Sciences, and published in Communications Earth & Environment, shows that the Margin Unit did not record a single lakeshore environment. Instead, the rocks preserve a layered history of multiple, distinct episodes in which water of different origins and temperatures moved through, altered, and reworked the crust. Groundwater percolated through fractures and left carbonate deposits behind. Lake water or evolving groundwater systems chemically transformed minerals that had formed earlier. And in a final act, warm hydrothermal fluids pushed through the fractured bedrock, depositing vein minerals that recorded yet another chapter in the crater’s watery past. The Margin Unit, the team concluded, became a kind of crossroads where several aqueous systems converged over geological time.

Bedford and an international team of collaborators pieced together this history using measurements and images from Perseverance, particularly the data returned by the rover’s SuperCam instrument. SuperCam, mounted on the rover’s mast or head, combines remote chemical analysis techniques, including laser-induced breakdown spectroscopy, with high-resolution imaging, allowing scientists to determine the composition of rocks and individual mineral grains from a distance. That capability proved essential on the Margin Unit, where the crucial evidence was written at scales invisible from orbit: fine fractures, thin mineral veins, and subtle chemical variations between grains that together revealed a sequence of water-rock interactions spanning a long stretch of Martian history.

“If there is one thing I have learned after 10 years working with Mars rovers, it is that Mars constantly throws surprises at you,” Bedford said. “It is very rare that things are as we expect them to be from orbital data. They are usually far more complex and interesting, which is what makes planetary exploration so exciting.” Her comment captures a recurring lesson of the Mars 2020 mission: orbital spectroscopy can flag promising locations, but only close-up, grain-scale analysis can reveal the true sequence of geological events preserved in the rocks.

The oldest chapter of the story begins deep underground. At higher elevations within the Margin Unit, Perseverance encountered coarse, crystalline rocks rich in olivine, an iron-magnesium silicate mineral commonly associated with igneous processes. The chemistry and texture of these olivine-bearing rocks suggest that they originally formed from a magma that cooled slowly beneath the Martian surface, allowing large crystals to grow. In other words, the foundation of the Margin Unit is not sediment laid down on a lakebed but volcanic rock crystallized in the crust, later exposed and made available for alteration by whatever water arrived afterward. This igneous starting point matters, because it gives scientists a well-defined baseline against which every subsequent chemical change introduced by water can be measured.

The first watery episode left an unmistakable signature at lower elevations. The team identified carbonate-rich ridges cutting across the bedrock, evidence that groundwater once traveled through a network of fractures and precipitated minerals along its path. Bedford offered an analogy drawn from terrestrial plumbing: “The fractures are like pipes, and the carbonate is the Mars ‘limescale’ that eventually blocked the ‘pipes’ up.” Just as hard water leaves mineral scale inside household pipes, the Martian groundwater left carbonate crusts inside its fracture conduits, gradually sealing them. These carbonate fills record the chemistry of the fluids that deposited them and, by extension, the subsurface environment of early Mars, making them prime targets in the search for conditions that could once have supported microbial life.

The story did not end with the groundwater. The rover also found widespread silica distributed through the lower-elevation rocks, along with clear evidence that previously formed carbonates had been chemically altered. That combination points to a second, later episode of water-rock interaction, one that may have involved water from Jezero’s ancient lake spilling into the margin rocks or shifts in the groundwater system itself changing the composition and flow paths of subsurface fluids. Either way, the alteration of the earlier carbonates demonstrates that the region’s water history was not a single event but a sequence of overlapping processes, each overprinting and modifying the record left by the last.

The final chapter is perhaps the most surprising. Perseverance discovered a mineral vein containing fluorite and calcium sulfate, a chemical pairing that points to a hydrothermal episode occurring after the groundwater and lake-related alteration had already taken place. Fluorite, the mineral form of calcium fluoride, typically precipitates from warm, chemically distinctive fluids, and its presence alongside calcium sulfate suggests that heated waters moved through the fractured bedrock late in the crater’s history. Hydrothermal systems are of special interest to astrobiologists because on Earth they support thriving ecosystems independent of sunlight, making similar environments on Mars compelling places to look for signs of past life. The vein indicates that even after Jezero’s lake had faded from the scene, the crust beneath it remained geologically and hydrologically active.

Taken together, the findings fundamentally reshape how scientists view the Margin Unit and, by extension, the history of water in Jezero Crater and across Mars. “Before we arrived at the Margin Unit, the main hypothesis was that these carbonates formed from interaction with the lake that existed in Jezero Crater, but now we know that this location became a sort of crossroads for aqueous systems, which significantly altered the crystalline volcanic rocks that were originally there,” Bedford said. Environments where water and rock interact repeatedly over long periods are precisely the kinds of settings that intrigue scientists studying the possibility of life on Mars, because such systems can supply energy and chemical gradients that living organisms can exploit. The Margin Unit had long been considered a promising research target since orbiting spacecraft first detected its strong carbonate signatures, but only Perseverance’s close-up view could reveal the fractures, mineral veins, and individual grains that exposed its far more complex history.

The research drew on the collective expertise of the SuperCam team, which Roger Wiens, professor of Earth, Atmospheric, and Planetary Sciences at Purdue, has led since before the launch of NASA’s Mars 2020 mission. Briony Horgan, professor of planetary science at Purdue, contributed to the work and served as campaign science lead during Perseverance’s exploration of the Margin Unit, and former Purdue doctoral students Stephanie Connell and Brad Garczynski also played important roles. Bedford, Wiens, and Connell received support from NASA for the SuperCam instrument. During its traverse, Perseverance collected rock samples from the Margin Unit, sealing them in tubes for a future mission intended to carry them to Earth. In terrestrial laboratories, those samples will be analyzed with instruments far more sensitive than anything a rover can carry, allowing scientists to examine the environments recorded in the rocks at microscopic scales and to assess their potential to preserve signs of ancient habitability.

“I hope this work helps to reshape how scientists view the history of water in Jezero Crater and across Mars,” Bedford said. “Ultimately, I hope this study helps planetary scientists reconstruct the changing climate and habitability of early Mars and provides helpful context for future researchers when these cached Perseverance samples are returned to Earth to be analyzed for potential biosignatures.” The paper, titled “Lake- and groundwater-associated alteration of the olivine-rich Margin Unit in Jezero Crater, Mars,” was accepted for publication in Communications Earth & Environment. For now, the findings stand as a vivid reminder that planetary surfaces keep their secrets at scales that only surface missions can reach, and that the red planet’s ancient waters were not a single still lake but a dynamic, evolving system whose shifting flows left an intricate, overlapping archive in the rocks along Jezero’s rim.

Subject of Research: Alteration of the olivine-rich Margin Unit in Jezero Crater, Mars, by groundwater, lake water, and hydrothermal fluids as observed by the Perseverance rover

Article Title: Purdue-led study finds an ancient history of water on Mars that shifted over time

Article References: Purdue-led study finds an ancient history of water on Mars that shifted over time. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Mars, Perseverance rover, Jezero Crater, Margin Unit, carbonates, groundwater, hydrothermal activity, SuperCam, olivine, astrobiology, water-rock interaction, Purdue University