Viruses that can help 'dial up' carbon capture in the sea

Armed with a catalog of hundreds of thousands of DNA and RNA virus species in the world's oceans, scientists are now zeroing in on the viruses most likely to combat climate change by helping trap carbon dioxide in seawater or, using similar techniques, different viruses that may prevent methane's escape from thawing Arctic soil.

By combining genomic sequencing data with artificial intelligence analysis, researchers have identified ocean-based viruses and assessed their genomes to find that they "steal" genes from other microbes or cells that process carbon in the sea. Mapping microbial metabolism genes, including those for underwater carbon metabolism, revealed 340 known metabolic pathways throughout the global oceans. Of these, 128 were also found in the genomes of ocean viruses.

"I was shocked that the number was that high," said Matthew Sullivan, professor of microbiology and director of the Center of Microbiome Science at The Ohio State University.

Having mined this massive trove of data via advances in computation, the team has now revealed which viruses have a role in carbon metabolism and are using this information in newly developed community metabolic models to help predict how using viruses to engineer the ocean microbiome toward better carbon capture would look.

"The modeling is about how viruses may dial up or dial down microbial activity in the system," Sullivan said. "Community metabolic modeling is telling me the dream data point: which viruses are targeting the most important metabolic pathways, and that matters because it means they're good levers to pull on."

Sullivan presented the research today (Feb. 17, 2024) at the annual meeting of the American Association for the Advancement of Science in Denver.

Sullivan was the virus coordinator for the Tara Oceans Consortium, a three-year global study of the impact of climate change on the world's oceans and the source of 35,000 water samples containing the microbial bounty. His lab focuses on phages, viruses that infect bacteria, and their potential to be scaled up in an engineering framework to manipulate marine microbes into converting carbon into the heaviest organic form that will sink to the ocean floor.

"Oceans soak up carbon, and that buffers us against climate change. CO2 is absorbed as a gas, and its conversion into organic carbon is dictated by microbes," Sullivan said. "What we're seeing now is that viruses target the most important reactions in these microbial community metabolisms. This means we can start investigating which viruses could be used to convert carbon toward the kind we want.

"In other words, can we strengthen this massive ocean buffer to be a carbon sink to buy time against climate change, as opposed to that carbon being released back into the atmosphere to accelerate it?"

In 2016, the Tara team determined that carbon sinking in the ocean was related to the presence of viruses. It is thought that viruses help sink carbon when virus-infected carbon-processing cells cluster into larger, sticky aggregates that drop to the ocean floor. The researchers developed AI-based analytics to identify from thousands of viruses which few are "VIP" viruses to culture in the lab and work with as model systems for ocean geoengineering.

This new community metabolic modeling, developed by collaborator Professor Damien Eveillard of the Tara Oceans Consortium, helps them understand what unintended consequences might be of such an approach. Sullivan's lab is taking these oceanic lessons learned and applying them to using viruses to engineer microbiomes in human settings to aid recovery from spinal cord injury, improve outcomes for infants born to mothers with HIV, combat infection in burn wounds, and more.

"The conversation we're having is, 'How much of this is transferable?'" said Sullivan, also a professor of civil, environmental and geodetic engineering. "The overall goal is engineering microbiomes toward what we think is something useful."

He also reported on early efforts to use phages as geoengineering tools in an entirely different ecosystem: the permafrost in northern Sweden, where microbes both change the climate and respond to climate change as the frozen soil thaws. Virginia Rich, associate professor of microbiology at Ohio State, is co-director of the National Science Foundation-funded EMERGE Biology Integration Institute based at Ohio State that organizes the microbiome science at the Sweden field site. Rich also co-led previous research that identified a lineage of single-cell organisms in the thawing permafrost soil as a significant producer of methane, a potent greenhouse gas.

Rich co-organized the AAAS session with Ruth Varner of the University of New Hampshire, who co-directs the EMERGE Institute, which is focusing on better understanding how microbiomes respond to permafrost thaw and the resulting climate interactions.

Sullivan's talk was titled "From ecosystems biology to managing microbiomes with viruses," and was presented at the session titled "Microbiome-Targeted Ecosystem Management: Small Players, Big Roles."

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New platform could boost development of carbon-capturing batteries

Efficient and cheap batteries that can also capture harmful emissions could be right around the corner, thanks to a new system that speeds up the development of catalysts for lithium-CO2 (Li-CO2) batteries.

The technology has been developed by the University of Surrey, Imperial College London, and Peking University to address the slow and inefficient methods currently used to produce catalysts for Li-CO2 batteries.

In the study, researchers used their tool to test and screen materials like platinum, gold, silver, copper, iron and nickel to easily investigate whether they would be suitable candidates for developing high-performing Li-CO2 batteries.

Dr Kai Yang, corresponding author of this work, project co-leader and Lecturer from the Advanced Technology Institute at the University of Surrey, explained:

"We have created a cutting-edge lab-on-a-chip electrochemical testing platform that can do multiple things at the same time. It helps evaluate electrocatalysts, optimise operation conditions, and study CO2 conversion in high-performance lithium-CO2 batteries. This new method is more cost-effective, efficient, and controllable than traditional ways of making these materials."

Li-CO2 batteries are a promising new type of battery that work by combining lithium and carbon dioxide; they not only store energy effectively but also offer a way to capture CO2, potentially making a dual-contribution to the fight against climate change.

Dr Yunlong Zhao, the lead corresponding author of this study and a Senior Lecturer at Imperial College London, the National Physical Laboratory, and visiting academic from the University of Surrey, said:

"It is crucial that we develop new negative emissions technologies. Our lab-on-a-chip platform will play a crucial role in advancing this goal. It will not only enhance our understanding of novel batteries, but it can also be applied to other systems like metal-air batteries, fuel cells, and photoelectrochemical cells.

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Extinct offshore volcano could store gigatons of carbon dioxide

A new study published in Geology concludes that an extinct volcano off the shore of Portugal could store as much as 1.2-8.6 gigatons of carbon dioxide, the equivalent of ~24-125 years of the country's industrial emissions. For context, in 2022 a total of 42.6 megatons (0.0426 gigatons) of carbon dioxide was removed from the atmosphere by international carbon capture and storage efforts, according to the Global CCS Institute. The new study suggests that carbon capture and storage in offshore underwater volcanoes could be a promising new direction for removal and storage of much larger volumes of the greenhouse gas from the atmosphere.

"We know that most countries, including Portugal, are making efforts to decarbonize the economy and our human activities, this is a message that this may be one of the instruments to solve the problem" says Ricardo Pereira, a geologist at the NOVA School of Science and Technology, and co-author of the study.

Storing carbon dioxide in an extinct volcano would rely on a process known as 'in situ mineral carbonation.' In this process, carbon dioxide reacts with elements in certain types of rocks to produce new minerals that safely and permanently store the carbon dioxide. Elements like calcium, magnesium, and iron combine with carbon dioxide to form the minerals calcite, dolomite, and magnesite, respectively. Rocks that contain large amounts of calcium, iron, and magnesium are ideal candidates for this process -- such as the volcanic basalts that make up most of the sea floor. Knowing this, the researchers targeted an offshore volcano for a few reasons -- the structure of the volcano could provide an ideal architecture for carbon injection and storage, the rocks are the right type for the reactions involved, and the location Is not too close to large populations, but also not too far.

Most carbon capture projects have relied on injection of carbon dioxide into porous sedimentary basins that are sealed to prevent migration of the gas out of reservoirs. In these cases, the carbon will eventually start to form minerals, but only over longer periods of time -- decades to centuries. In 2016, researchers published findings that 95% of carbon dioxide injected into underground basalts in Iceland had mineralized within just two years. The much shorter mineralization time makes the process safer and more effective -- once carbon is stored in minerals, issues like potential leaks are no longer a concern.

Davide Gamboa, a geologist at the University of Aveiro and co-author of the study, explains, "What makes mineral carbonation really interesting is the time. The faster it gets into a mineral, the safer it becomes, and once it's a mineral, it is permanent."

The researchers studied the storage potential at the ancient Fontanelas volcano, which is partially buried ~100 kilometers offshore from Lisbon, with a peak ~1500 meters below sea-level.

To estimate the potential volume of carbon dioxide that could be stored at this site, the authors used 2D and 3D seismic studies of the undersea volcano that had been produced during offshore oil exploration, as well as data from samples that had been dredged from the area in 2008. The dredged samples contained naturally formed carbonate minerals, indicating that the chemical reactions required to store carbon were already happening, and that intentional efforts to mineralize carbon in these rocks should be successful. The samples also had up to 40% pore space -- meaning there are spaces within the rocks where carbon dioxide could be injected and mineralized. The researchers also indicate that low-permeability layers imaged around the flanks of the volcano could help with containing the carbon dioxide before it is mineralized.

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Increased droughts are disrupting carbon-capturing soil microbes, concerning ecologists

Soil stores more carbon than plants and the atmosphere combined, and soil microbes are largely responsible for putting it there. However, the increasing frequency and severity of drought, such as those that have been impacting California, could disrupt this delicate ecosystem. In a perspective publishing in the journal Trends in Microbiology on April 12, microbial ecologist Steven Allison warns that soil health and future greenhouse gas levels could be impacted if soil microbes adapt to drought faster than plants do. He argues that we need to better understand how microbes respond to drought so that we can manage the situation in both agricultural and natural settings.

"Soil microbes are beneficial, and we couldn't live without their cycling of carbon and nutrients, but climate change and drought can tweak that balance, and we have to be aware of how it's changing," says Allison of the University of California, Irvine.

Some soil microbes take carbon from decomposing plants and store it in the soil, while others release plant carbon back into the atmosphere. The carbon that ends up in the soil is beneficial in multiple ways. "The carbon in the soil has these reverberating effects out to the rest of the world in terms of the infrastructure in our natural and managed ecosystems," says Allison. "Carbon-rich soils hold more nutrients, so plants growing in those soils tend to be more productive, and the carbon changes the physical properties of the soil, which prevents erosion."

"In California now, we have this system where the droughts are more intense, and then the rainfall is more intense," he says. "So, if you're losing your soil carbon, when it rains really hard it could carry away your soil and cause erosion, landslides, mudslides, sediments, and all kinds of problems that we're actually seeing right now."

The carbon that is released back into the atmosphere is another story. "From a climate mitigation standpoint, what we want is for more carbon to be in plants and soils and less carbon to be in the atmosphere, so the more carbon we can absorb into plants through photosynthesis and the more we can transfer and keep in the soil, the better off we're going to be in terms of climate change," says Allison. "That's why it's really important to know how the balance of incoming versus outflowing carbon changes with drought, or warming, or any other climate factor."

Plants and microbes will both be impacted by the increasing frequency of drought, but Allison suspects that microbes will be able to bounce back faster. "Microbes are really adaptable -- they can change their physiology, they can change their abundances so that more drought-adapted microbes take over, and they can potentially evolve -- so we expect that they are going to resist or bounce back from drought," says Allison. "All those different processes can happen pretty quickly with microbes, and much more quickly than with plants."

If more carbon-releasing microbes survive than carbon-sequestering microbes, we could end up with carbon-depleted soils, which would have serious negative implications for plant productivity and future greenhouse gas levels.

We may be able to nudge the balance in the right direction, Allison says, but more research is needed first. "There's still a lot to be done. Right now, we have data that suggests that when we have drought, something changes that results in carbon loss, but we don't understand exactly how or why that's happening, whether drought's changing the abundance of beneficial plant associated microbes versus the carbon releasing microbes, or if it's causing the evolution of one of the microbe groups, or if it's more determined by changes to their immediate physiology," says Allison.

Some microbes could actually help plants cope with drought. If we knew which microbes were most beneficial to plants, and most likely to retain carbon in soil, we could try to tip the balance in their favor.

"There's a lot of potential for us to manage or engineer soil microbes," says Allison. "In agricultural systems, we can look into manipulating the soil or adding beneficial microbes back in. In more natural systems, management would probably be on the plant side: soil microbes are often closely intertwined with plants, so managing the plants can also benefit the microbial part of the ecosystem."

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A simple, cheap material for carbon capture, perhaps from tailpipes

Using an inexpensive polymer called melamine -- the main component of Formica -- chemists have created a cheap, easy and energy-efficient way to capture carbon dioxide from smokestacks, a key goal for the United States and other nations as they seek to reduce greenhouse gas emissions.

The process for synthesizing the melamine material, published this week in the journal Science Advances, could potentially be scaled down to capture emissions from vehicle exhaust or other movable sources of carbon dioxide. Carbon dioxide from fossil fuel burning makes up about 75% of all greenhouse gases produced in the U.S.

The new material is simple to make, requiring primarily off-the-shelf melamine powder -- which today costs about $40 per ton -- along with formaldehyde and cyanuric acid, a chemical that, among other uses, is added with chlorine to swimming pools.

"We wanted to think about a carbon capture material that was derived from sources that were really cheap and easy to get. And so, we decided to start with melamine," said Jeffrey Reimer, Professor of the Graduate School in the Department of Chemical and Biomolecular Engineering at the University of California, Berkeley, and one of the corresponding authors of the paper.

The so-called melamine porous network captures carbon dioxide with an efficiency comparable to early results for another relatively recent material for carbon capture, metal organic frameworks, or MOFs. UC Berkeley chemists created the first such carbon-capture MOF in 2015, and subsequent versions have proved even more efficient at removing carbon dioxide from flue gases, such as those from a coal-fired power plant.

But Haiyan Mao, a UC Berkeley postdoctoral fellow who is first author of the paper, said that melamine-based materials use much cheaper ingredients, are easier to make and are more energy efficient than most MOFs. The low cost of porous melamine means that the material could be deployed widely.

"In this study, we focused on cheaper material design for capture and storage and elucidating the interaction mechanism between CO2 and the material," Mao said. "This work creates a general industrialization method towards sustainable CO2 capture using porous networks. We hope we can design a future attachment for capturing car exhaust gas, or maybe an attachment to a building or even a coating on the surface of furniture."

The work is a collaboration among a group at UC Berkeley led by Reimer; a group at Stanford University led by Yi Cui, who is director of the Precourt Institute for Energy, the Somorjai Visiting Miller Professor at UC Berkeley, and a former UC Berkeley postdoctoral fellow; UC Berkeley Professor of the Graduate School Alexander Pines; and a group at Texas A&M University led by Hong-Cai Zhou. Jing Tang, a postdoctoral fellow at Stanford and the Stanford Linear Accelerator Center and a visiting scholar at UC Berkeley, is co-first author with Mao.

Carbon neutrality by 2050

While eliminating fossil fuel burning is essential to halting climate change, a major interim strategy is to capture emissions of carbon dioxide -- the main greenhouse gas -- and store the gas underground or turn CO2 into usable products. The U.S. Department of Energy has already announced projects totaling $3.18 billion to boost advanced and commercially scalable technologies for carbon capture, utilization and sequestration (CCUS) to reach an ambitious flue gas CO2 capture efficiency target of 90%. The ultimate U.S. goal is net zero carbon emissions by 2050.

But carbon capture is far from commercially viable. The best technique today involves piping flue gases through liquid amines, which bind CO2. But this requires large amounts of energy to release the carbon dioxide once it's bound to the amines, so that it can be concentrated and stored underground. The amine mixture must be heated to between 120 and 150 degrees Celsius (250-300 degrees Fahrenheit) to regenerate the CO2.

In contrast, the melamine porous network with DETA and cyanuric acid modification captures CO2 at about 40 degrees Celsius, slightly above room temperature, and releases it at 80 degrees Celsius, below the boiling point of water. The energy savings come from not having to heat the substance to high temperatures.

In its research, the Berkeley/Stanford/Texas team focused on the common polymer melamine, which is used not only in Formica but also inexpensive dinnerware and utensils, industrial coatings and other plastics. Treating melamine powder with formaldehyde -- which the researchers did in kilogram quantities -- creates nanoscale pores in the melamine that the researchers thought would absorb CO2.

Mao said that tests confirmed that formaldehyde-treated melamine adsorbed CO2 somewhat, but adsorption could be much improved by adding another amine-containing chemical, DETA (diethylenetriamine), to bind CO2. She and her colleagues subsequently found that adding cyanuric acid during the polymerization reaction increased the pore size dramatically and radically improved CO2 capture efficiency: Nearly all the carbon dioxide in a simulated flue gas mixture was absorbed within about 3 minutes.

The addition of cyanuric acid also allowed the material to be used over and over again.

Mao and her colleagues conducted solid-state nuclear magnetic resonance (NMR) studies to understand how cyanuric acid and DETA interacted to make carbon capture so efficient. The studies showed that cyanuric acid forms strong hydrogen bonds with the melamine network that helps stabilize DETA, preventing it from leaching out of the melamine pores during repeated cycles of carbon capture and regeneration.

"What Haiyan and her colleagues were able to show with these elegant techniques is exactly how these groups intermingle, exactly how CO2 reacts with them, and that in the presence of this pore-opening cyanuric acid, she's able to cycle CO2 on and off many times with capacity that's really quite good," Reimer said. "And the rate at which CO2 adsorbs is actually quite rapid, relative to some other materials. So, all the practical aspects at the laboratory scale of this material for CO2 capture have been met, and it's just incredibly cheap and easy to make."

"Utilizing solid-state nuclear magnetic resonance techniques, we systematically elucidated in unprecedented, atomic-level detail the mechanism of the reaction of the amorphous networks with CO2," Mao said. "For the energy and environmental community, this work creates a high-performance, solid-state network family together with a thorough understanding of the mechanisms, but also encourages the evolution of porous materials research from trial-and-error methods to rational, step-by-step, atomic-level modulation."

The Reimer and Cui groups are continuing to tweak the pore size and amine groups to improve the carbon capture efficiency of melamine porous networks, while maintaining the energy efficiency. This involves using a technique called dynamic combinatorial chemistry to vary the proportions of ingredients to achieve effective, scalable, recyclable and high-capacity CO2 capture.

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Cheaper, more efficient ways to capture carbon

University of Colorado Boulder researchers have developed a new tool that could lead to more efficient and cheaper technologies for capturing heat-trapping gases from the atmosphere and converting them into beneficial substances, like fuel or building materials. Such carbon capture technology may be needed at scale in order to limit global warning this century to 2.7 degrees F (1.5 Celsius) above pre-industrial temperatures and fend off catastrophic impacts of global climate change.

The scientists describe their technique in a paper published this month in the journal iSCIENCE.

The method predicts how strong the bond will be between carbon dioxide and the molecule that traps it, known as a binder. This electrochemical diagnosis can be easily applied to any molecule that is chemically inclined to bind with carbon dioxide, allowing researchers to identify suitable molecular candidates with which to capture carbon dioxide from everyday air.

"The Holy Grail, if you will, is to try to inch toward being able to use binders that can grab carbon dioxide from the air [around us], not just concentrated sources," said Oana Luca, co-author of the new study and assistant professor of chemistry. "Determining the strength of binders allows us to figure out whether the binding will be strong or weak, and identify candidates for future study for direct carbon capture from dilute sources."

The goal of carbon capture and storage technology is to remove carbon dioxide from the atmosphere and store it safely for hundreds or thousands of years. But while it has been in use in the U.S. since the 1970s, it currently captures and stores a mere 0.1% of global carbon emissions annually. To help meet carbon emissions goals laid out by the IPCC, carbon capture and storage would have to rapidly increase in scale by 2050.

Current industrial facilities around the world rely on capturing carbon dioxide from a concentrated source, such as emissions from power plants. While these methods can bind a lot of carbon dioxide quickly and efficiently using large amounts of certain chemical binders, they are also extraordinarily energy intensive.

This method also is quite expensive at scale to take carbon dioxide and turn it into something else useful, such as carbonates, an ingredient in cement, or formaldehyde or methanol, which can be used as a fuel, according to Luca, fellow-elect of the Renewable and Sustainable Energy Institute (RASEI).

Using electrochemical methods instead, such as those detailed in the new CU Boulder-led study, would free carbon capture facilities from being tied to concentrated sources, allowing them to exist almost anywhere.

Being able to easily estimate the strength of chemical bonds also enables researchers to screen for which binders will be best suited -- and offer a cheaper alternative to traditional methods -- for capturing and converting carbon into materials or fuel according to Haley Petersen, co-lead author on the study and graduate student in chemistry.

Creating chemical bonds

The science of chemistry is based on a few basic facts: One, that molecules are made of atoms, and two, that they are orbited by electrons. When atoms bond with other atoms, they form molecules. And when atoms share electrons with other atoms, they form what is called a covalent bond.

Using electricity, the researchers can activate these bonds by using an electrode to deliver an electron to a molecule. When they do that to an imidazolium molecule, like they did in this study, a hydrogen atom is removed, creating a gap in a carbon atom for another molecule to want to bond with it -- such as carbon dioxide.

However, carbon dioxide (CO2) is the kind of molecule that doesn't typically like to create new bonds.

"It's generally unreactive, and in order to react with it, you also have to bend it," said Luca. "So we're in a chemical space that hasn't really been probed before, for CO2 capture."

The method the researchers examines how good a whole family of carbenes (a specific type of molecule, containing a neutral carbon atom), that they can electrochemically generate, are at binding CO2.

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Safer carbon capture and storage

Atmospheric carbon dioxide (CO2) levels have increased significantly over the last 50 years, resulting in higher global temperatures and abrupt changes to Earth's climate. Carbon capture and storage (CCS) is one of the new technologies that scientists hope will play an important role in tackling the climate crisis. It involves the capture of CO2 from emissions from industrial processes, or from the burning of fossil fuels in power generation, which is then stored underground in geological formations. CCS will also be key if we want to produce "clean-burning" hydrogen from hydrocarbon systems.

The UK government recently selected four sites to develop multi-billion-pound CCS projects as part of its scheme to cut 20-30m tonnes of CO2 per year by 2030 from heavy industry. Other countries have made similar carbon reduction commitments.

Depleted hydrocarbon reservoirs have a smaller (10%) storage potential compared to deep saline aquifers but are seen as a critical early opportunity in developing geological CO2 storage technologies. Fortuitously, CO2 has historically been injected into numerous depleted hydrocarbon reservoirs as a means of enhanced oil recovery (CO2-EOR). This provides a unique chance to evaluate the (bio)geochemical behaviour of injected carbon over engineering timescales.

'CCS will be a key tool in our battle to avert climate change. Understanding how CCS works in practice, in addition tocomputer modelling and lab-based experiments, is essential to provide confidence in safe and secure CO2 geologicalsequestration.' Said Dr. Rebecca Tyne, Dept Earth Science, The University of Oxford

In a paper published, today in Nature, Dr. Rebecca Tyne and Prof. Chris Ballentine from Oxford University, lead a team of international collaborators to investigate the behaviour of CO2 within a CO2-EOR flooded oil field in Louisiana, USA. They compared (bio)geochemical composition of the CO2-EOR flooded field with that of an adjacent field, which was never subjected to CO2-EOR. Data suggest that up to 74% of CO2 left behind by CO2-EOR was dissolved in the groundwater. Unexpectedly, it also revealed, that microbial methanogenesis converted as much as 13-19% of the injected CO2 to methane, which is a stronger greenhouse gas than CO2.

This study is the first to integrate state of the art isotopic tracers (noble gas, clumped and stable isotope data) with microbiological data to investigate the fate of the injected CO2.

'Methane is less soluble, less compressible and less reactive than CO2, so, if produced, the reduces the amount of CO2 we can safely inject into these sites. However, now this process has been identified, we can take it into account in future CCS site selection.' Said Prof. Chris Ballentine, Dept. Earth Sciences, The University of Oxford.

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