It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, February 27, 2024
Many reported gender differences may actually be power differences
OVERALL COMPARISON OF THE EXPERIMENTAL POWER LITERATURE AND SEX/GENDER DIFFERENCE META-ANALYSES. OVERALL, 70.6% OF SEX/GENDER DIFFERENCES WERE CONSISTENT WITH THE EFFECTS OF EXPERIMENTALLY INDUCED POWER DIFFERENCES, WHEREAS ONLY 7.8% WERE INCONSISTENT. WHEN HIGHPOWER INDIVIDUALS SCORED HIGHER ON AN OUTCOME, MEN TENDED TO ALSO SCORE HIGHER ON THAT OUTCOME. SIMILARLY, WHEN LOW-POWER INDIVIDUALS SCORED HIGHER ON AN OUTCOME, WOMEN TENDED TO SCORE HIGHER ON THAT OUTCOME.
Why do men and women seem so different? According to a study, a wide range of gender differences that have been attributed to biological sex may actually be due to differences in power. Psychological differences between men and women have multiple possible explanations, including natural selection for sex-specific adaptations on the one hand and socialization processes on the other hand. Contributing to this debate, Adam D. Galinsky and colleagues took advantage of a recent boom in sex/gender difference meta-analyses and a separate boom in psychological experiments that varies who has more versus less power. Their analyses explored whether some reported sex/gender differences are actually due to the fact then men tend to have more power than women in society. For example, studies on sex/gender differences show that men tend to display more agency than women and that women tend to be more interpersonally sensitive than men. But many studies that randomly assign some individuals to high power and others to low power find that those with power exhibit more agency and those without power are more sensitive towards others. Linking these experimental findings on power with sex difference meta-analyses, the authors found that of 102 outcomes associated with men, 72 were also empirically linked to people with power, whereas only 8 outcomes associated with women were also associated with power. Men and people with power tend to display higher agency, more positive self-evaluations, lower empathy and sociability, and higher performance on spatial and creative tasks compared to low-power individuals and women. According to the authors, this strong connection between sex differences and power differences suggests that many sex/gender differences may be driven, at least in part, by power differences between men and women.
JOURNAL
PNAS Nexus
ARTICLE TITLE
Are many sex/gender differences really power differences?
ARTICLE PUBLICATION DATE
27-Feb-2024
Scientists use blue-green algae as a surrogate mother for "meat-like" proteins
CREDIT: (FROM FIGURE 2 IN THE SCIENTIFIC ARTICLE: HTTPS://PUBS.ACS.ORG/DOI/10.1021/ACSNANO.3C08600)
We all know that we ought to eat less meat and cheese and dig into more plant-based foods. But whilst perusing the supermarket cold display and having to choose between animal-based foods and more climate-friendly alternative proteins, our voices of reason don’t always win. And even though flavour has been mastered in many plant-based products, textures with the 'right' mouthfeel have often been lacking.
Furthermore, some plant-based protein alternatives are not as sustainable anyway, due to the resources consumed by their processing.
But what if it was possible to make sustainable, protein-rich foods that also have the right texture? New research from the University of Copenhagen is fueling that vision. The key? Blue-green algae. Not the infamous type known for being a poisonous broth in the sea come summertime, but non-toxic ones.
"Cyanobacteria, also known as blue-green algae, are living organisms that we have been able to get to produce a protein that they don’t naturally produce. The particularly exciting thing here is that the protein is formed in fibrous strands which somewhat resemble meat fibers. And, it might be possible to use these fibres in plant-based meat, cheese or some other new type of food for which we are after a particular texture," says Professor Poul Erik Jensen of the Department of Food Science.
In a new study, Jensen and fellow researchers from the University of Copenhagen, among other institutions, have shown that cyanobacteria can serve as host organisms for the new protein by inserting foreign genes into a cyanobacterium. Within the cyanobacterium, the protein organizes itself as tiny threads or nanofibers.
Minimal processing – maximum sustainability
Scientists around the world have zoomed in on cyanobacteria and other microalgae as potential alternative foods. In part because, like plants, they grow by means of photosynthesis, and partly because they themselves contain both a large amount of protein and healthy polyunsaturated fatty acids.
"I'm a humble guy from the country side who rarely throws his arms into the air, but being able to manipulate a living organism to produce a new kind of protein which organizes itself into threads is rarely seen to this extent – and it is very promising. Also, because it is an organism that can easily be grown sustainably, as it survives on water, atmospheric CO2 and solar rays. This result gives cyanobacteria even greater potential as a sustainable ingredient," says an enthusiastic Poul Erik Jensen, who heads a research group specializing in plant-based food and plant biochemistry.
Many researchers around the world are working to develop protein-rich texture enhancers for plant-based foods – e.g., in the form of peas and soybeans. However, these require a significant amount of processing, as the seeds need to be ground up and the protein extracted from them, so as to achieve high enough protein concentrations.
"If we can utilize the entire cyanobacterium in foodstuffs, and not just the protein fibers, it will minimize the amount of processing needed. In food research, we seek to avoid too much processing as it compromises the nutritional value of an ingredient and also uses an awful lot of energy," says Jensen.
Tomorrow’s cattle
The professor emphasizes that it will be quite some time before the production of protein strands from cyanobacteria begins. First, the researchers need to figure out how to optimize the cyanobacteria's production of protein fibers. But Jensen is optimistic:
"We need to refine these organisms to produce more protein fibres, and in doing so, 'hijack' the cyanobacteria to work for us. It’s a bit like dairy cows, which we’ve hijacked to produce an insane amount of milk for us. Except here, we avoid any ethical considerations regarding animal welfare. We won’t reach our goal tomorrow because of a few metabolic challenges in the organism that we must learn to tackle. But we’re already in the process and I am certain that we can succeed," says Poul Erik Jensen, adding:
"If so, this is the ultimate way to make protein."
Cyanobacteria such as spirulina are already grown industrially in several countries – mostly for health foods. Production typically occurs in so-called raceway ponds beneath the open sky or in photobioreactors chambers, where the organisms grow in glass tubes.
According to Jensen, Denmark is an obvious place to establish "microalgae factories" to produce processed cyanobacteria. The country has biotech companies with the right skills and an efficient agricultural sector.
"Danish agriculture could, in principle, produce cyanobacteria and other microalgae, just as they produce dairy products today. It would be possible to harvest, or milk, a proportion of the cells as fresh biomass on a daily basis. By concentrating cyanobacteria cells, you get something that looks like a pesto, but with protein strands. And with minimal processing, it could be incorporated directly into a food."
CYANOBACTERIA PAVED THE WAY FOR THE REST OF US
Cyanobacteria, also known as blue-green algae, are not related to algae, despite the name. They belong to the bacterial kingdom.
Their ability to photosynthesize makes them unique. In fact, cyanobacteria are believed to have invented photosynthesis around 3.8 billion years ago. As such, they have played an important role in Earth's evolution by oxygenating our planet’s atmosphere. This paved the way for every organism that feeds on oxygen. (Source: Wikipedia).
Certain cyanobacteria can produce toxins that can cause respiratory paralysis or destroy the liver, and are fatal to mammals, birds and fish. In rare cases, cyanobacteria have caused deaths in humans.
In the research community, there is also great interest in using the cell walls of cyanobacteria as a biomaterial that could replace wood or cement. This is because cyanobacteria accumulate various polymers (macromolecules) that in principle, can be used as building blocks in bioplastics.
ABOUT THE STUDY
The researchers behind the study are: Julie A. Z. Zedler, Alexandra M Schirmacher, David A Russo and Paul Verkade of Friedrich-Schiller-Universität Jena; Lorna Hodgson of the University of Bristol; Stefanie Frank from University College London; Emil Gundersen and Annemarie Matthes from the Department of Plant and Environmental Sciences at the University of Copenhagen and Poul Erik Jensen from the Department of Food Science at the University of Copenhagen.
The research is supported by the EU's Horizon 2020 programme, The Humboldt Foundation, the Biotechnology and Biological Sciences Research Council (BBSRC), the Novo Nordisk Foundation and the Carlsberg Foundation.
A closed photo bioreactor where micro algae are cultivated in glass tubes
IN OUR SIMPLIFIED EXAMPLE, WE ASSUME THAT ALICE, BOB, CARL AND DAVID INCLUDE ALL OTHER “GOOD” DEPOSITS IN THEIR RESPECTIVE ASSOCIATION SETS AND EXCLUDE DEPOSIT 5, THAT ORIGINATES FROM A KNOWN ILLICIT SOURCE. EVE, ON THE OTHER HAND, CANNOT CREATE A PROOF THAT DISASSOCIATES HER WITHDRAWAL FROM HER OWN DEPOSIT.
Blockchain's inherent transparency, while beneficial for validation and trust, poses significant privacy concerns. Traditional transactions on public blockchains are permanently visible, compromising user privacy. This visibility has been a double-edged sword, providing transparency but at the cost of personal data exposure. A new protocol called Privacy Pools offers a potential solution to the seemingly contradictory goals of blockchain privacy and regulatory compliance.
In a recent study ( doi: https://doi.org/10.1016/j.bcra.2023.100176 ) published in Blockchain: Research and Applications on 21 February 2023, contributed by Vitalik Buterin (co-founders of Ethereum), Jacob Illum, Matthias Nadler, Fabian Schär, and Ameen Soleimani. The researchers have developed a protocol called "Privacy Pools" that enhances privacy on blockchain transactions while complying with regulatory standards. This new smart contract-based protocol enables users to prove specific attributes of their transactions without exposing their entire history, maintaining both privacy and transparency.
The "Privacy Pools" protocol introduces a novel approach by allowing users to publish zero-knowledge proofs. These proofs confirm whether their funds are associated with lawful or unlawful sources without revealing their entire transaction history. This method involves proving membership in pre-defined association sets, aligned with regulatory frameworks, thus separating compliant from non-compliant transactions.
"This study offers a promising approach to reconciling the seemingly conflicting goals of blockchain privacy and regulatory compliance," said Dr. Fabian Schär, the corresponding author of this article. "By enabling users to prove compliance without revealing their entire transaction history, Privacy Pools could pave the way for a more privacy-preserving and inclusive blockchain ecosystem."
The "Privacy Pools" protocol offers a pragmatic solution to the long-standing challenge of maintaining privacy in blockchain transactions while meeting regulatory requirements. This innovation not only enhances user privacy but also strengthens the integrity and trustworthiness of blockchain technology. It demonstrates that privacy and regulatory compliance can coexist, paving the way for more secure and private financial transactions in the digital age.
Blockchain: Research and Applications is an international, peer reviewed journal for researchers, engineers, and practitioners to present the latest advances and innovations in blockchain research. The journal publishes theoretical and applied papers in established and emerging areas of blockchain research to shape the future of blockchain technology.
THE INCREASED OXIDATIVE DECOMPOSITION POTENTIAL IS IN EVIDENCE AT 4.63 V ALLOWING THE POTENTIAL FORMATION OF A PASSIVATION LAYER. THE ILLUSTRATIONS SHOW THE THREE MOST CRITICAL FINDINGS SUMMARIZED; A HIGH FLAME RETARDANCY (UPPER LEFT CORNER), THE CREATION OF A PASSIVATION LAYER ON THE CATHODE AS TPPO DECOMPOSES (LOWER LEFT CORNER) AND A REPRESENTATION OF THE STRUCTURAL AND MOLECULAR ORBITAL ENERGY OF TPPO THAT WAS USED TO PREDICT THE ADDITIVE’S ABILITY TO FORM A PASSIVATION LAYER (LOWER RIGHT CORNER).
CREDIT: ENERGY MATERIALS AND DEVICES, TSINGHUA UNIVERSITY PRESS
In our technologically dependent society, the mobility, dependability and safety of our devices, including phones and laptops, is critical. Just as important is our ability to easily charge and recharge these devices so they are available when we need them. To do this, we use rechargeable batteries, specifically lithium-ion batteries (LIB). They give us the freedom of movement and connectivity we need. As society’s needs evolve, so too does our tech, and so too must the batteries that allow us to use this tech. One of the most urgent concerns regarding lithium-ion batteries is their safety. Though rare, there are issues with explosions and fires caused by electrochemical system instability. “Consequently, there is an urgent need to develop LIBs that can provide higher energy density, longer cycle life and improved safety,” said Ying Bai, corresponding author of the paper and a professor at Beijing Institute of Technology in China.
Beijing scientists have been researching the use of additives in the sulfone-based electrolyte of lithium-ion batteries to improve their performance. They found that by adding triphenylphosphine oxide (TPPO), “that the TPPO improves the thermal stability of the electrolyte, which has important industrial value and foundational significance of TPPO as an additive for advancing the development of LIB’s,” said Chuan Wu, co-corresponding author on the paper and a professor at Beijing Institute of Technology.
When lithium-ion batteries are discharging lithium-ions, they move from an anode, which is an electrode where current enters the battery, through an electrolyte pass through a separator to a cathode, which is where the current leaves the storage battery to energize a device. The path is reversed when recharging. “In the composition of the battery, the non-aqueous electrolyte used in LIBs plays a crucial role in determining key performance parameters such as cycle life, power density and efficiency,” said Ying Bai. Power density is a measure of stored power per volume and cycle life is the number of charge/discharge cycles that a battery can undergo before it starts to decrease the percentage of charge it can hold.
The electrolyte solutions in use now have some issues with cycle stability, thermal stability and safety. Rather than completely changing the electrolyte solution, they chose to test the use of an additive, TPPO, in the electrolyte to improve the performance of the overall battery.
TPPO when tested was found to have several important properties. “Firstly, it reduces the flame point of the sulfone electrolyte; Secondly, it selectively forms a stable passivation film, enhancing the interface stability between the sulfone electrolyte and the electrode material,” said Chuan Wu. The passivation film forms as the TPPO decomposes and coats the cathode, rendering it more resistant to wear and tear, similarly reducing the breakdown of the electrolyte while enhancing the movement of the lithium-ions across the electrolyte.
Using theoretical calculations, electrochemical characterization and flammability tests, the researchers found “that the addition of 2 wt.% TPPO to the sulfone-based electrolyte significantly enhances the ionic conductivity within the temperature range of 20–60°C. Additionally, it increases the discharge capacity of LIBs in the range of 2–4.8 V while maintaining excellent rate performance and cycling stability. Flammability tests and thermal gravimetric analysis (TGA) results indicate the excellent non-flammability and thermal stability of the electrolyte,” said Ying Bai.
In short, the new electrolyte that they have developed is safer as it is non-flammable, is thermally stable and has an increased energy discharge capacity.
Other contributors include Qiaojun Li, Wenya Wu, Haixia Ren from the School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, China; Yu Li from the School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, China, and Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, China.
This research was supported by the National Key Research and Development Program of China, the Science and Technology Program of Guangdong Province, funding from General Research Institute for Nonferrous Metals and the Beijing Institute of Technology Research Fund Program for Young Scholars.
Energy Materials and Devices is launched by Tsinghua University, published quarterly by Tsinghua University Press, aiming at being an international, single-blind peer-reviewed, open-access and interdisciplinary journal in the cutting-edge field of energy materials and devices. It focuses on the innovation research of the whole chain of basic research, technological innovation, achievement transformation and industrialization in the field of energy materials and devices, and publishes original, leading and forward-looking research results, including but not limited to the materials design, synthesis, integration, assembly and characterization of devices for energy storage and conversion etc.
SciOpen is a professional open access resource for discovery of scientific and technical content published by the Tsinghua University Press and its publishing partners, providing the scholarly publishing community with innovative technology and market-leading capabilities. SciOpen provides end-to-end services across manuscript submission, peer review, content hosting, analytics, and identity management and expert advice to ensure each journal’s development by offering a range of options across all functions as Journal Layout, Production Services, Editorial Services, Marketing and Promotions, Online Functionality, etc. By digitalizing the publishing process, SciOpen widens the reach, deepens the impact, and accelerates the exchange of ideas.
EACH CHARACTERISTIC DISPLAYED IN AN INTEGRAL PART IN ENSURING THE FUNCTION OF THE SCC CAN BE USED TO IMPROVE UPON TRADITIONAL CARBON MATERIALS USED IN ENERGY STORAGE AND CONVERSION DEVICES.
There’s a lot of research about moving away from carbon as an energy source, but what if instead the carbon that is being used is applied to its full capacity?
The importance of carbon as an energy source is not to be downplayed. Unfortunately, the reliance on these carbon-based materials has proven to be disastrous for the environment, especially in the quantities they are consumed on a global basis. Therefore, alternative means have to be researched. Superstructure carbons (SCC) are a possible way to use carbons in a more efficient and “green” way that can exceed the current performance and longevity of the standard materials in energy storage and conversion devices.
SCCs are multifaceted in both their construction and performance but also in their concept as a whole. It starts with the fact that they are, indeed, carbons. While this might not seem like a step to reduce overall carbon dependency, it is a way to make the carbons being used more intentionally with more direct functions that can lead to better performance and functionality.
“This unique category satisfies the particular functional demands of high-performance devices and surpasses the rigid structure of traditional carbons,” said Debin Kong, researcher and author of the study.
SSCs are carbon-based materials that are built precisely for the material it’s interfacing with, whether that’s a lithium-ion (Li) battery, lithium sulfide (LiS) battery or a metal-air battery.
There are three main characteristics of these SCCs presented by researchers for successful development and implementation: precisely customized pores, freely adjusted frameworks and highly coupled interfaces.
Having precisely customized pores has the advantage of improved surface utilization and mass transfer over traditional carbon materials. Using a porous carbon as part of the active material in energy-storage devices (like batteries) can improve metrics such as the specific capacity of the material. The specific capacity is the amount of an electrical charge that can be delivered to the material per gram of the material’s weight. Freely adjusted frameworks are crucial to allow for rapid electron transfer between the inner workings of the materials, including the carbon unit and electrode. Finally, highly coupled interfaces allow for an additional improvement in electron transfer, which is a significant element in improving the overall function and performance of a battery. Interfaces that work well together allow for electrochemical reactions to occur more easily and without issues such as aggregation, or the formation of clusters of nanoparticles.
“Overall, the concept of SSCs shows a way to solve the problems faced by current carbons, which is important to the practical applications of advanced carbons and their relevant high performance energy related devices in future,” said Kong.
Researchers aren’t aiming to just improve carbon-based active materials with this review, but are looking to create new highs for carbon structures. Performance breakthroughs are an ultimate goal, aiming to shatter bottlenecks in the performance of energy conversion and storage. However, there are always difficulties to consider and wrinkles to iron out with further research.
The most important thing to consider is that different devices have different needs. Li, LiS and metal-air batteries are likely to all have a different relationship with SCCs that needs to be fully fleshed out to ensure suitability and compatibility. Additionally, the cost and performance of SCCs need to be examined before it becomes a practical and widespread solution. This can include refining the preparation process and the precursors needed to lower the cost and simplify production. Another point that needs further research is the overall understanding of the carbon microstructure and its structural evolution depending on the carbon precursor used.
Debin Kong, Wei Lv, Yanbing He, and Feiyu Kang of the Shenzhen Giem Graphene Center and Engineering Laboratory for Functionalized Carbon Materials at Tsinghua University with Debin Kong also of the College of New Energy at China University of Petroleum, Ruliang Liu, Dingcai Wu, and Ruowen Fu of the Materials Science Institute at Sun Yat-sen University, Feng Li of the Shenyang National Laboratory for Materials Science at the Chinese Academy of Sciences and Quan-Hong Yang of the Nanoyang Group at the School of Chemical Engineering and Technology at Tianjin University all contributed to this research.
The National Basic Research Program of China, the National Nature Science Foundation of China, and the Taishan Scholar Project of Shandong Province made this research possible.
Energy Materials and Devices is launched by Tsinghua University, published quarterly by Tsinghua University Press, aiming at being an international, single-blind peer-reviewed, open-access and interdisciplinary journal in the cutting-edge field of energy materials and devices. It focuses on the innovation research of the whole chain of basic research, technological innovation, achievement transformation and industrialization in the field of energy materials and devices, and publishes original, leading and forward-looking research results, including but not limited to the materials design, synthesis, integration, assembly and characterization of devices for energy storage and conversion etc.
SciOpen is a professional open access resource for discovery of scientific and technical content published by the Tsinghua University Press and its publishing partners, providing the scholarly publishing community with innovative technology and market-leading capabilities. SciOpen provides end-to-end services across manuscript submission, peer review, content hosting, analytics, and identity management and expert advice to ensure each journal’s development by offering a range of options across all functions as Journal Layout, Production Services, Editorial Services, Marketing and Promotions, Online Functionality, etc. By digitalizing the publishing process, SciOpen widens the reach, deepens the impact, and accelerates the exchange of ideas.
ATLANTA — Three corporate landlords control nearly 11 percent of the single-family homes available for rent in metro Atlanta’s core counties, according to a new analysis led by Taylor Shelton, a geographer at Georgia State University.
Shelton, an assistant professor in the Department of Geosciences at Georgia State, along with his collaborator Eric Seymour of Rutgers University, investigated the ownership of rental homes in metro Atlanta and found that more than 19,000 were owned by just three companies — Invitation Homes, Pretium Partners and Amherst Holdings. The findings were published recently in the article “Horizontal Holdings: Untangling the Networks of Corporate Landlords” in the Annals of the American Association of Geographers, the discipline’s flagship journal.
“These companies own tens of thousands of properties in a relatively select set of neighborhoods, which allows them to exercise really significant market power over tenants and renters because they have such a large concentration of holdings in those neighborhoods,” Shelton said.
Metro Atlanta is facing an affordable housing crisis, and corporate landlords may be one of the reasons for that, according to a book by fellow GSU researcher Dan Immergluck. Beginning with the 2007 foreclosure crisis and continuing in the wake of the COVID-19 pandemic, many local landlords and homeowners were forced or decided to sell their properties, enabling companies that purchase buildings and rent them out for a profit, called corporate landlords, to snap up large numbers of homes.
In this new landscape, figuring out exactly who owns each property can be incredibly complicated.
Many large companies in the United States operate through smaller companies called limited liability companies, or LLCs for short. In the case of corporate landlord companies, these LLCs help protect the larger parent companies from liability or legal action that tenants might take.
“If a tenant is able to sue an LLC and win — they receive some level of damages and compensation for whatever harm they experience — the structure in place means that only the assets held by the LLC are used in calculating the appropriate level of damages,” Shelton said.
Shelton said corporate landlords tend to have a lot of LLCs to protect themselves. In the core metro Atlanta counties in his study — Fulton, Clayton, DeKalb, Gwinnett and Cobb — the three largest landlord companies have more than 190 LLCs between them.
These LLCs usually have multiple addresses, making it difficult to trace the ties between their locations and their parent companies.
To make things even more complex, many of these large companies are not traded publicly on the stock market, meaning their total number of holdings is not easily available to the public. Because Invitation Homes is publicly traded, the total number of properties it owns is available to the public through documents it is required to file with the U.S. Securities and Exchange Commission.
“The other two we analyze in this paper, Pretium Partners and Amherst Holdings, are backed by private equity and not publicly traded,” Shelton said. “So, there is no way to ever know what the full scope of their holdings are without a method like the one we used.”
Tenants find themselves with few options when they have a problem with their corporate landlord.
“Layers of interaction that have to happen before you get to the person who’s ultimately making decisions are increased. You have to talk to your property manager,” Shelton said. “Then, the property manager has to talk to their supervisor, who talks to the local or regional manager. Then they have to run things up. It creates this distance where you don’t actually know who your landlord is, so you don’t actually know who to make demands of.”
This is particularly relevant for Atlanta, which is the largest market for this kind of corporate landlord activity in the country, according to another study byShelton and Seymour.
“You have to add up the next two or three largest markets in the U.S. together to have the same amount of corporate landlord investment that Atlanta has,” Shelton said.
Shelton said metro Atlanta is one of the largest markets for this kind of activity for a few reasons.
“Corporate landlords like places that are growing, and they like places where housing is relatively cheap,” Shelton said. “But the other box that Atlanta checks is that we have very lax tenant protections.”
To address the situation, Shelton and his fellow researchers decided to make their methods of investigation available to the public.
“The hope is that anybody can take this method and replicate it even if you don’t have significant technical skills,” Shelton said. “We wanted to get to the skeleton of the logic of this process so that anyone can do it for anywhere and any company. All you need to have is the right data and then you can go from there.”
AMHERST, Mass. – A team of researchers from the University of Massachusetts Amherst that specializes in accounting for the carbon dioxide release by streams, rivers and lakes recently demonstrated that the chemical process known as “carbonate buffering” can account for the majority of emissions in highly alkaline waters. Furthermore, carbonate buffering distorts the most commonly used method of tracking the origins of CO2 in streams. The research, published in Global Biogeochemical Cycles, proposes a better method for tracking the origin of riverine CO2 emissions.
Inland waters, including streams, rivers and lakes, account for roughly 5.5 gigatons of CO2 emissions annually – about 15% of what humans emit. But current climate models have trouble accounting for this carbon, in part because, says Matthew Winnick, assistant professor of Earth, Geographic and Climate Sciences at UMass Amherst and the paper’s lead author, much of this carbon seems to be produced cryptically, through carbonate buffering. “The process is a little weird,” says Winnick. “It acts as a kind of hidden reserve pool of CO2, replenishing carbon that is lost to the atmosphere, and ultimately increasing the amount of CO2 available for off-gassing.”
To show how this hidden pool operates, Winnick and his co-author, then-UMass graduate student Brian Saccardi, looked to studies that focused on the carbon content of the oceans. “Carbonate buffering is a really well-known phenomenon in the ocean,” says Winnick, “and even though oceans work differently from inland waters, we were able to borrow the geochemical equations to build a series of models that could account for a wide range of river and stream conditions.”
So what is carbonate buffering? It begins with CO2—which is everywhere: in the air, in the soil and in water. When CO2 dissolves in water, it can react to form carbonic acid, which, through further reactions, can then become bicarbonate and carbonate. This reaction can also run in reverse, which means that high levels of bicarbonate and carbonate can act as reserve pools of CO2, driving emissions. This entire balance of CO2, water and carbonate is called “carbonate buffering,” and the carbonate reserves can be emitted as a greenhouse gas from stream systems. Indeed, Winnick and Saccardi found that this hidden pool can account for more than 60% of CO2 emissions under alkaline conditions.
There’s yet another trick that carbonate buffering has up its sleeve. In the era of global warming, it is critically important to know both how much carbon is being emitted overall and where this carbon is coming from. “While we don’t think stream emissions contribute to global warming, there is a big question about whether these emissions will change as climate warms, which could amplify warming in the future. To predict changes, we need to know where the CO2 is coming from,” says Winnick. But figuring out which molecule of CO2 came from which source is not a simple task. To track carbon, especially carbon emitted by bodies of water, scientists often use carbon isotopes, or versions of carbon with different masses, which act as a sort of forensic signature that can indicate the carbon’s origin.
However, Winnick and Saccardi discovered that isotope signals in streams are highly sensitive to carbonate buffering reactions. “The primary way we use isotopes to track sources is through their relationship with CO2 concentrations, but carbonate buffering causes these relationships to break down,” says Winnick. This breakdown can point to the wrong carbon culprit if not properly accounted for.
One way to account for carbonate buffering is to measure multiple isotopes of carbon, the new study suggests. Scientists typically only focus on one of the two tracer isotopes, because of the high cost of analyzing both, but the team has found that tracking the origins of both isotopes can help unmask the hidden sources of CO2.
