Polystyrene waste is everywhere

Scientists just found a way to break it down

DOE/AMES LABORATORY

Research News

 

Scientists at the U.S. Department of Energy's Ames Laboratory and their partners from Clemson University have discovered a green, low-energy process to break down polystyrene, a type of plastic that is widely used in foam packaging materials, disposable food containers, cutlery, and many other applications.

Polystyrene is part of a much larger global plastic waste problem. Hundreds of millions metric tons of polymers are produced each year, a large majority of which is discarded after use. Due to the chemical stability and durability of industrial polymers, plastic waste does not easily degrade in landfills and is often burned, which produces carbon dioxide and other hazardous gases. In order to stop the growing flood of polymer waste and reduce carbon dioxide emissions, plastics have to be recycled or converted into new value-added products.

Currently, recycling of the vast majority of plastics is not economically feasible; their sorting and separation are time and labor intensive, while chemical processing and remanufacturing requires a significant energy input and toxic solvents. Re-processed polymers often show inferior performance to that of the freshly manufactured "made from scratch" materials.

A team of scientists at Ames Laboratory used processing by ball-milling to deconstruct commercial polystyrene in a single step, at room temperature, in ambient atmosphere in the absence of harmful solvents. Ball-milling is a technique that places materials in a milling vial with metal ball bearings which is then agitated until a desired chemical reaction occurs. Called mechanochemistry, this experimental approach has numerous applications in new materials synthesis, and attractive features where plastics recycling is concerned.

The deconstruction of polystyrene proceeds through a series of chemical events involving mechanical cutting apart of the macromolecules, which generates free radicals detectable in the milled material even after its prolonged exposure to air. The metal bearings used for milling and the ambient oxygen act as co-catalysts that enable extraction of the monomeric styrene from the oligomeric radical-bearing species formed. The experiments showed that the temperature rise in the material during milling is not responsible for the observed phenomenon since the temperature inside the milled powder does not exceed 50oC while the thermal decomposition of polystyrene in air starts at about 325oC. The Clemson's group confirmed the comprehensive deconstruction of the original polymer into smaller fragments, oligomeric materials, suitable for further processing into new value-added products.

"This method represents an important breakthrough that enables dismantling of a polymer simultaneously with its break-down under ambient conditions, that is, ~300oC below the thermal decomposition temperature of the pristine material" said Ames Laboratory Senior Scientist Viktor Balema. "We think this proof of concept is an exciting possibility for developing new recycling technologies for all kinds of plastics, and that will contribute to establishment of the circular economy."

His partner from Clemson University, Kentwool Distinguished Professor Igor Luzinov, further commented that "this discovery opens new avenues for low temperature recovery of monomers from multicomponent polymer based systems such as composites and laminates. Also, our technology will allow extracting the monomer from crosslinked materials containing styrene units in their structures."

Alfred P. Sloan Foundation Research Fellow, Professor Aaron Rossini of Iowa State University, further noted that "electron paramagnetic resonance spectroscopy shows large concentrations of free radical carbon-centered species in polystyrene that was milled in air. This is a startling result because free radicals are normally very reactive. Also, the presence of the radicals gives direct evidence that the milling directly causes scission of the polymer chains. We expect that the reactive sites associated with the free radicals can be used to functionalize the processed polymers to obtain new value-added products."

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The research was funded in part by Ames Laboratory's Laboratory Directed Research and Development (LDRD) Program.

The research is further discussed in the paper "Depolymerization of polystyrene under ambient conditions," authored by Viktor P. Balema, Ihor Z. Hlova, Scott L. Carnahan, Mastooreh Seyedi, Oleksandr Dolotko, Aaron J. Rossini, and Igor Luzinov; featured on the front cover of the New Journal of Chemistry.

Ames Laboratory is a U.S. Department of Energy Office of Science National Laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

Ames Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit https://energy.gov/science.

Pioneering study gives new insight into formation of copper deposits

UNIVERSITY OF EXETER

Research News

 

A groundbreaking study has given new insights into how copper deposit-forming fluids are transported naturally from their source deep underground towards the Earth's surface.

A team of geologists, led by Lawrence Carter from the University of Exeter's Camborne School of Mines, has published a new theory for how porphyry copper deposits form.

Porphyry deposits provide around 75 per cent of the world's copper which is in increasing demand for electric vehicles, power infrastructure and green technologies such as wind turbines. They originally develop several kilometres below the Earth's surface above large magma chambers. Not only are porphyry deposits rare but most large near-surface examples have already been found. Any new model for how and where they form will be of great interest to mining companies.

In the new study, the researchers have shown that vast quantities of mineralising fluids could be extracted and transported from their source magmas and focussed into the ore-forming environment through 'crystal mush dykes'.

Lawrence Carter, a final year PhD student at Camborne School of Mines, based at the University of Exeter's Penryn Campus said: "Our study addresses the missing link in models for the formation of porphyry-type copper deposits - how vast quantities of mineralising fluids are extracted and transported from their source magmas and focussed into the ore-forming environment.

"In doing so we provide the first field, petrographic and microscale evidence for fluid transport through what we term 'crystal mush dykes'. Their recognition is paramount to the development of more reliable porphyry exploration models and has significance for other ore-forming systems and volcanic processes."

Collaborating with scientists from the British Geological Survey (BGS) and University of Surrey, this research involved field studies and micro-textural and geochemical analyses of samples from the archetypal Yerington porphyry district in Nevada, where an exceptional ~8 km palaeo-vertical cross-section through a number of porphyry copper deposit systems is exposed.

The team were able to identify a wormy interconnected network of quartz within dykes found in rocks that were once beneath the copper deposits. This represents palaeo-porosity in a once permeable magmatic crystal mush of feldspar and quartz. The mush acted as conduits for vast quantities of porphyry-deposit-forming fluids from deep portions of underlying magmas.

It is believed that this breakthrough may provide insights for the discovery of new porphyry copper deposits, and the proposed mechanism key to the formation of other ore deposit types as well as degassing processes in volcanic systems.

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NERC GW4+ DTP, the Society of Economic Geologists Foundation and the NERC highlight topic 'FAMOS' supported the research.

The paper, entitled "Crystal mush dykes as conduits for mineralising fluids in the Yerington porphyry copper district, Nevada", is published in the leading journal Nature Communications Earth & Environment on March 17th 2021.

Socioeconomic factors play key role in COVID-19 impact on Blacks, Hispanics

AMERICAN THORACIC SOCIETY

Research News

 

IMAGE: BLACKS, HISPANICS MORE IMPACTED BY #COVID-19 DUE TO FACTORS SUCH AS INCOME, NEIGHBORHOOD, HOUSEHOLD SIZE view more 

CREDIT: ATS

March 17, 2021-- A new study published online in the Annals of the American Thoracic Society reveals how socioeconomic factors partially explain the increased odds that Black and Hispanic Americans have of testing positive for SARS-CoV-2, the virus that causes COVID-19.

In "Association of Race and Ethnicity With COVID-19 Test Positivity and Hospitalization Is Mediated by Socioeconomic Factors," Hayley B. Gershengorn, MD, associate professor, Division of Pulmonary, Critical Care and Sleep Medicine, University of Miami Miller School of Medicine and co-authors looked at the medical records of 15,473 patients tested and 295 hospitalized with COVID-19 between March 1, 2020 and July 23, 2020 at University of Miami hospitals and clinics. This research was conducted as a retrospective cohort study--one that follows two groups of former patients.

Dr.Gershengorn and colleagues found that the socioeconomic factors of population density at the patient's recorded address, median income, and household size were significantly related to race/ethnicity and explained some of the relation of race/ethnicity with both test positivity and hospitalization. They found no association between race or ethnicity with death rates or other outcomes for hospitalized patients.

"The associations between race/ethnicity and test positivity or hospitalization were not as strong once we adjusted for these socioeconomic factors," she said.

Of patients who were tested for SARS-CoV-2, 29.0 percent were non-Hispanic white, 48.1 percent were Hispanic white, 15.0 percent were non-Hispanic Black, 1.7 percent were Hispanic Black, and 1.6 percent were "other." Among those tested, 1,256 patients (8.1 percent) tested positive and, of the hospitalized patients, 47 (15.9 percent) died. After adjustment for demographics, race/ethnicity was associated with test positivity and hospitalization.

The researchers conducted a mediation analysis to see if household income, population density and household size explained the association of race and ethnicity with COVID-19 outcomes. Mediation analysis is a statistical technique to help explain underlying reasons for an association of an exposure (in this case, race/ethnicity) and an outcome (in this case, test positivity).

"Numerous studies have demonstrated an association of race and/or ethnicity with outcomes (e.g., case positivity, hospitalization, and, sometimes, mortality) in COVID-19," saidDr.Gershengorn. "Specifically, we have seen that, on the whole, non-white and/or Hispanic people tend to fare worse than non-Hispanic white individuals. Appropriately, much has been written about how these associations with worse outcomes almost assuredly have little to do with differences in biology or intrinsic susceptibility to infection across races and ethnicities. Rather, these associations reflect external factors to which minority individuals are more often subject. One of these proposed factors is socioeconomic circumstance; this hypothesis has face validity, but had not been demonstrated in COVID-19. We set out to prove that socioeconomic disparities mediate the association of race and/or ethnicity with worse outcomes in COVID-19."

Of the three socioeconomic factors the researchers examined, they found that median income mediated the largest proportion of COVID-19 positive tests--27 percent. Population density mediated 17 percent and household size mediated 20 percent.

"We found that all three socioeconomic factors were associated with higher odds of test positivity, regardless of race or ethnicity," she stated. "For example, after accounting for other differences, individuals of all races and ethnicities living in the highest population density neighborhoods had 2.5-fold higher odds of test positivity than those living in areas with the lowest population density." Death following hospitalization for COVID-19 was no more common for Black or Hispanic patients than for non-Hispanic white patients.

The researchers believe it would be useful for similar studies to be done in other regions of the U.S.--and parts of the world--with different ethnic/racial makeups and socioeconomic pressures, in order to show the consistency of their findings in other settings and to better understand which (if any) socioeconomic factors impact the association of race and ethnicity with COVID-19 outcomes.

The research team finds it likely that the associations they found between the specific social determinants of health they evaluated and disease risk would be generalizable to other infections with droplet and airborne transmission. Improvements in the social situations of all patients living in more crowded, less well-off communities may pay dividends for their health when the next pandemic, or the next season of influenza, hits.

Dr. Gershengorn adds, "We need to recognize that however much we measure and adjust for potential mediators--socioeconomic factors, access to health care, access to education--we still have structural racism in this country that likely drives many health-related outcomes for minority people. Quantifying the impact of structural racism is important, but more important is working to abolish it."

The Blue Economy is more than resources: It has to focus on social equity and governance

UNIVERSITY OF BRITISH COLUMBIA

Research News

 

IMAGE: DIMENSIONS AND CRITERIA USED TO EVALUATE CAPACITY TO ESTABLISH AN EQUITABLE, SUSTAINABLE, AND VIABLE BLUE ECONOMY ('BLUE ECONOMY CAPACITY) view more 

CREDIT: ANDRES CISNEROS-MONTEMAYOR

The future of an equitable and sustainable global ocean, or "Blue Economy," depends on more than the resources available for technological advancement and industry expansion. A recent UBC-led study found that socioeconomic and governance conditions such as national stability, corruption and human rights greatly affect the ability to achieve a Blue Economy.

The study, published today in Nature, scored criteria across five global regions: Africa, Americas, Asia, Europe and Oceania, to identify the areas of investment and research necessary to develop ocean resources in a manner that is consistent with a Blue Economy ethos (socially equitable, environmentally sustainable and economically viable). These included: infrastructure, investment, economic and group equity, gender equality, human rights, biodiversity, habitat, water quality, corruption, and national stability.

"We found that there are considerable differences between regions, where some are focused primarily on resources, whereas others are really trying to make sure that development is meeting local social and cultural objectives," said lead author Andrés Cisneros-Montemayor, research associate for the Institute for the Oceans and Fisheries at the University of British Columbia and deputy director of the Nippon Foundation Ocean Nexus Center. "For all countries, including Canada, the most important question we need to be asking is, how are we going to make sure that we develop those resources in ways that actually benefit local communities? Otherwise we're back to business-as-usual, where only a few benefit from ocean resources. This is what the Blue Economy is trying to change."

As natural resources are widely but unevenly distributed across the oceans, many areas will be unable to competitively develop multiple sectors. It is, therefore, important to choose and manage sectors carefully, as development for sectors like ecotourism, fishing, mariculture, or others, can be important at local scales but may not be ecologically sustainable or socially desirable at larger scales. Ocean-based development plans for Asia and Europe, for example, do prioritize mariculture and tourism, but also sectors such as shipping, port construction, and large-scale ocean energy projects which have potential for economic growth, but unclear benefits for local communities. Oceania, on the other hand, has prioritized community objectives, traditional resource uses, and emerging sectors that can be developed in accordance with local goals. In other words, more focus on developing and transforming their ocean economies to advance equity and sustainability.

"Canada is in a great position to be a leader on this, with coastlines on three oceans and a lot of local knowledge and capacity to develop sectors carefully," said Cisneros-Montemayor. "It is currently in the process of developing it Blue Economy plan, yet, we are now seeing that the draft, which at the time our study was just being prepared, is very much focused on new technologies. Yet, as a nation, Canada has very publicly focused on equity, inclusion and deeper issues such as Indigenous reconciliation. We have to make sure that those national priorities are fully part of Canada's Blue Economy strategy and create an example that others can learn from. And yet these priorities are not currently reflected in its Blue Economy draft. What is happening in the oceans is not fundamentally different than the issues happening at a national level."

"History has taught us that having rich natural resources does not necessarily support sustainable development, and this applies to ocean economies as well" said William Cheung, co-author on the paper, professor in the Institute for the Oceans and Fisheries and Canada Research Chair in Ocean Sustainability and Global Change). "Global and local investment in the blue economy needs to prioritize in enhancing knowledge and their accessibility, developing appropriate and effective governance, improving social equity and reducing risks to the ocean such as from biodiversity loss and climate change."

"Enabling conditions for an equitable and sustainable blue economy" was published today in Nature.

CAPTION

Distribution of dimension scores across oceans, regions, and development groups

CREDIT

Gabriel Reygondeau

Low-education voters disregard policy beliefs at the polls, research finds

Voters who support left-wing social welfare programs vote against left-wing candidates

UNIVERSITY OF CALIFORNIA - RIVERSIDE

Research News

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IMAGE: LOW-EDUCATION VOTERS ARE MORE LIKELY TO ABANDON THEIR SOCIAL WELFARE POLICY BELIEFS AT THE VOTING BOOTH. view more 

CREDIT: LUIS SANZ / UC RIVERSIDE

Many people who embrace social welfare programs vote against their own interests, according to new UC Riverside research.

The mitigating factor is education: The more education one has, the more likely one is to stick to one's policy preferences.

"It means candidates who employ tactics such as fear and attaching patriotism to certain concepts can persuade people to vote for candidates who are in opposition to their social beliefs," Diogo Ferrari, a professor of political science at UC Riverside, wrote in his recently published paper, "Education, Belief Structures, Support for Welfare Polices, and Vote," published in the journal Education & Society.

For the study, Ferrari looked at public opinion surveys collected in 2016 in more than 30 European, Asian, and North American countries. The surveys included information about peoples' education, and 18 questions gauging attitudes toward social welfare policies including social security, unemployment, education, health spending, industry financing, and income redistribution. Lastly, the survey asked which political party the respondent voted for in the last general election.

Among people with low education, social programs such as old-age pensions and giving financial aid to low-income students are met with support. Unemployment insurance, in particular, is popular among those with low education, defined as having a high school education or less. The program is about three times more popular than among those with high education, meaning at least an undergraduate degree.

"The least-educated support social protection more than the most-educated, as do the poorest groups within the same education group," Ferrari wrote.

But support for left-wing policies among people with low education doesn't translate to support for left-wing parties. It's not just left-wing beliefs and voting that are misaligned among the least educated voters: Attitudes against social welfare don't necessarily align with right-wing voting, either.

"It's only when schooling is high that ... positions are harmonized with the vote for right-wing or left-wing parties," Ferrari wrote. "Less-educated groups contradict, in behavior (vote), their attitudinal tendency to support welfare policies."

Ferrari wrote it makes them prey to the "demagogue candidate" who uses "caricatured notions of right and left to position himself politically before less attentive voters."

That could mean aligning party politics with patriotism, religion, or the promise of eliminating political corruption. And so, voters with low education can end up voting against their own interests.

"The idea is to deviate people's attention from some of the things they care about and focus on their attitudes on other areas," Ferrari said. "A candidate can emphasize anti-illegal-immigration policy, or economic nationalism, or anti-political-elite positions.

"The implication of the study is that, everything else the same, (such tactics) seem more effective among those who are less educated."

More educated voters, meanwhile, are less likely than low-educated voters to sacrifice their policy preferences and vote for parties more distant in terms of policy positions.

Ferrari's findings build on a long-held position among political scientists. In 1964's "The Nature of Belief Systems," political scientist Philip Converse argued citizens can't process large quantities of political information, which leads to a lack of structure and stability in their views. He asserted that, when people are asked to pair the terms "liberal" and "conservative" with ideology, they struggle.

Ferrari's new research qualifies that argument, asserting formal education can prevent that misalignment.

"The idea is that formal education, or schooling, makes people more likely to use broad organizing conceptual schemes such as notions of 'conservatism' and 'liberalism' to evaluate political affairs and categorize political actors," Ferrari said. "The fact is that we can clearly distinguish policy preferences between some social groups, and the match between those preferences and vote is stronger among the most educated, which indicates they are less likely to 'sacrifice' their overall policy preferences in favor of a few other 'issues of the day' when voting."

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Abundant and stable rocks are critical egg-laying habitat for insects in restored streams

NORTH CAROLINA STATE UNIVERSITY

Research News

 

IMAGE: A RECENT STUDY HIGHLIGHTS THE IMPORTANCE OF ROCK CHARACTERISTICS IN STREAM HABITAT, WHICH SHOULD INFORM STREAM RESTORATION EFFORTS. HERE, FIRST AUTHOR SAMANTHA JORDT RECORDS THE PRESENCE OF INSECT EGGS IN... view more 

CREDIT: MICHELLE JEWELL

The abundance and other characteristics of rocks partially extending above the water surface could be important for improving the recovery of aquatic insect populations in restored streams.

Nearly three quarters of stream insects reproduce on large rocks that sit above the water surface by crawling underneath to attach their eggs. Increasing the number of large and stable emergent rocks in streams could provide more egg-laying habitat and allow insects to quickly repopulate restored streams.

"We found that restored streams had fewer emergent rocks for egg-laying and fewer total eggs than naturally intact streams," says Samantha Jordt, first author of the paper and an M.Sc. student at NC State's Department of Applied Ecology.

The study also found that some of the large rocks in restored streams were unstable and rolled or were buried by sediment between Samantha's visits. According to the study, these variables combined-fewer large rocks available for egg laying and that some of those rocks were unstable-may delay insect recovery.

"When a rock rolls, any eggs on that rock will likely be destroyed either by being crushed or scraped off as the rock rolls, being buried by sediment, or by drying out if the rock settles into a new position that exposes the eggs to the air," says Jordt. "You end up with lots of insects laying eggs on the one good rock in the stream, truly putting all of their eggs in one, rolling, basket."

Less suitable egg-laying habitat means fewer larvae or adult insects - both important for the long term health and recovery of restored streams. Aquatic insects provide several ecosystem services, including breaking down leaf litter, consuming algae, cycling nutrients, and being food for fish, salamanders, and birds.

"Many people rely on streams for drinking water, which means they rely on all of the ecological processes that happen upstream before the water reaches them," says Jordt. "Aquatic insects maintain water quality for free. So we develop techniques so that restored streams have habitats that they can rebound and thrive in."

Most stream restoration projects focus on the recovery of physical and chemical aspects. This study highlights how incorporating the natural history of aquatic insects will be another critical tool for both the initial design and the long-term success of restoring streams.

"Unavailable or unstable egg-laying habitat may be a primary reason why biological recovery in restored streams lags decades behind geomorphological and hydrological recovery," says Brad Taylor, co-author of the paper and assistant professor of applied ecology at NC State. "Ensuring stable and suitable rocks for insect egg-laying could be a small design change to increase the return on our multi-million-dollar investment in stream restoration."

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The article, "A rolling stone gathers no eggs: the importance of stream insect egg laying natural history for stream restoration," was published in the journal Ecology on 12 March 2021. The paper is authored by Samantha Jordt and Brad Taylor from NC State's Department of Applied Ecology. The research was funded by the North Carolina Department of Environmental Quality and Division of Mitigation Services.

Nurse work environment influences stroke outcomes

UNIVERSITY OF PENNSYLVANIA SCHOOL OF NURSING

Research News

 

PHILADELPHIA (March 17, 2021) - Stroke remains a leading cause of death worldwide and one of the most common reasons for disability. While a wide variety of factors influence stroke outcomes, data show that avoiding readmissions and long lengths of stay among ischemic stroke patients has benefits for patients and health care systems alike. Although reduced readmission rates among various medical patients have been associated with better nurse work environments, it is unknown how the work environment might influence readmissions and length of stay for ischemic stroke patients.

In a new study from the University of Pennsylvania School of Nursing's (Penn Nursing) Center for Health Outcomes and Policy Research (CHOPR), researchers evaluated the association between the nurse work environment and readmission and length of stay for close to 200,000 hospitalized adult ischemic stroke patients in more than 500 hospitals. They found that in hospitals with better nurse work environments, ischemic stroke patients experienced lower odds of 7? and 30?day readmissions and lower lengths of stay.

Their research has been published in the journal Research in Nursing & Health. The article "Better Nurse Work Environments Associated with Fewer Readmissions and Shorter Length of Stay Among Adults with Ischemic Stroke: A Cross?Sectional Analysis of United States Hospitals" is available online.

"The work environment is a modifiable feature of hospitals that should be considered when providing comprehensive stroke care and improving post?stroke outcomes," says Heather Brom, PhD, RN, NP-C, lecturer at Penn Nursing and lead author of the article. "Our findings have important implications for quality improvement initiatives for stroke care management."

Creating good work environments for nurses is especially important so that they have adequate time to spend with stroke patients and can communicate effectively with all team members and feel supported by managers to make decisions about nursing care. "All of these aspects of the nurse work environment facilitate an effective and efficient discharge planning process, which has the potential to decrease delays in discharge and avoidable readmissions," says J. Margo Brooks Carthon, PhD, RN, FAAN, Associate Professor of Nursing and one of the co-authors of the article.

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Additional co-authors include Mathew McHugh, PhD, JD, MPH,RN, FAAN, director of the Center for Health Outcomes and Policy Research (CHOPR) at Penn Nursing, Linda Aiken, PhD, RN, FAAN, FRCN, founding director of CHOPR, and Douglas Sloane, PhD, Senior Fellow at CHOP

A new view on plate tectonics

Nature study finds transform faults play active role in shaping ocean floors

HELMHOLTZ CENTRE FOR OCEAN RESEARCH KIEL (GEOMAR)

Research News

 

Forces acting inside the Earth have been constantly reshaping the continents and ocean basins over millions of years. What Alfred Wegener published as an idea in 1915 has finally been accepted since the 1960s, providing a unifying view about our planet. The fact that the theory of plate tectonics took so long to gain acceptance had two simple reasons. First, the geological formations that are most important for its understanding lie at the bottom of the oceans. Secondly, forces controlling the processes act below the seafloor and are hence hidden from our view. Many details of plate tectonics are therefore still unclear today.

Today, five scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel, the Southern University of Science and Technology (Shenzhen, China) and GeoModelling Solutions GmbH (Switzerland) publish a study in the international scientific journal Nature that questions a previous basic assumption of plate tectonics. It is about so-called transform faults. "These are large offsets in the mid-ocean ridges. So far, they have been assigned a purely passive role within plate tectonics. However, our analyses show that they are definitely actively involved in shaping the ocean floors," explains Prof. Ingo Grevemeyer from GEOMAR, lead author of the study.

A look at a global overview map of the ocean floors helps to understand the study. Even at low resolution, several tens of thousands of kilometres long mid-ocean ridges can be recognised on such maps. They mark the boundaries of the Earth's plates. In between, hot material from the Earth's interior reaches the surface, cools down, forms new ocean floor and pushes the older ocean floor apart. "This is the engine that keeps the plates moving," explains Prof. Grevemeyer.

However, the mid-ocean ridges do not form unbroken lines. They are cut by transverse valleys at almost regular intervals. The individual segments of the ridges each begin or end in an offset at these incisions. "These are the transform faults. Because the Earth is a sphere, plate movements repeatedly cause faults that produce these ridge offsets," explains Prof. Lars Rüpke from GEOMAR, co-author of the study.

Earthquakes can occur at the transform faults and they leave long scars, so-called fracture zones, on oceanic plates. Until now, however, research assumed that the two plates only slide past each other at transform faults, but that seafloor is neither formed nor destroyed in the process.

The authors of the current study have now looked at available maps of 40 transform faults in all ocean basins. "In all examples, we could see that the transform valleys are significantly deeper than the adjacent fractures zones, which were previously thought to be simple continuations of the transform valleys," says co-author Prof. Colin Devey from GEOMAR. The team also detected traces of extensive magmatism at the outer corners of the intersections between transform valleys and the mid-ocean ridges.

Using sophisticated numerical models, the team found an explanation for the phenomenon. According to this, the plate boundary along the transform fault is increasingly tilted at depth, so that shearing occurs. This causes extension of the seafloor, forming the deep transform valleys. Magmatism at the outer corners to the mid-ocean ridges then fills up the valleys, so that the fracture zones become much shallower. Oceanic crust that forms at the corners is therefore the only crust in the ocean that is formed by two-stage volcanism. What effects this has on its composition or, for example, the distribution of metals in the crust is still unknown.

Since transform faults are a fundamental type of plate boundary and frequent phenomenon along active plate boundaries in the oceans, this new finding is an important addition to the theory of plate tectonics and thus to understanding our planet. "Actually, the observation was obvious. But there are simply not enough high-resolution maps of the seafloor yet, so no one has noticed it until now," says Prof. Grevemeyer.

Double-duty catalyst generates hydrogen fuel while cleaning up wastewater

AMERICAN CHEMICAL SOCIETY

Research News

 

Hydrogen is a pollution-free energy source when it's extracted from water using sunlight instead of fossil fuels. But current strategies for "splitting" or breaking apart water molecules with catalysts and light require the introduction of chemical additives to expedite the process. Now, researchers reporting in ACS ES&T Engineering have developed a catalyst that destroys medications and other compounds already present in wastewater to generate hydrogen fuel, getting rid of a contaminant while producing something useful.

Harnessing the sun's energy to split water to make hydrogen fuel is a promising renewable resource, but it is a slow process even when catalysts are used to speed it along. In some cases, alcohols or sugars are added to boost the rate of hydrogen production, but these chemicals are destroyed as hydrogen is generated, meaning the approach is not renewable. In a separate strategy, researchers have tried using contaminants in wastewater to enhance hydrogen fuel generation. While titanium-based catalysts worked for both removing contaminants and generating hydrogen, the efficiencies were lower than expected for both steps because of their overlapping reaction sites. One way to reduce such interferences is to make catalysts by fusing together different conductive metals, thus creating separate places for reactions to occur. So, Chuanhao Li and colleagues wanted to combine cobalt oxide and titanium dioxide to create a dual-functioning catalyst that would break down common drugs in wastewater while also efficiently converting water into hydrogen for fuel.

To make the catalyst, the researchers coated nanoscale titanium dioxide crystals with a thin layer of cobalt oxide. Initial tests showed that this material didn't produce much hydrogen, so as a next step, the team spiked this dual catalyst with 1% by weight of platinum nanoparticles -- an efficient though expensive catalyst for generating hydrogen. In the presence of simulated sunlight, the platinum-impregnated catalyst degraded two antibiotics and produced substantial amounts of hydrogen. Finally, the team tested their product on real wastewater, water from a river in China and deionized water samples. Under simulated sunlight, the catalyst stimulated hydrogen production in all three samples. The greatest amount of hydrogen was obtained from the wastewater sample. The researchers say their catalyst could be a sustainable wastewater treatment option by generating hydrogen fuel at the same time.

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The authors acknowledge funding from National Natural Science Foundation of China, Science and Technology Planning Project of Guangdong Province, Fundamental Research Funds for the Central Universities from Sun Yat-sen University and the Research Fund Program of Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology.

The abstract that accompanies this paper is available here.

For more of the latest research news, register for our upcoming meeting, ACS Spring 2021. Journalists and public information officers are encouraged to apply for complimentary press registration by emailing us at newsroom@acs.org.

New study reveals habitat that could increase jaguar numbers

DEFENDERS OF WILDLIFE

Research News

 

Tucson, Ariz. (March 16, 2021) - This week, a new, peer-reviewed scientific study finds that there is far more potential jaguar habitat in the U.S. than was previously thought. Scientists identified an area of more than 20 million acres that could support jaguars in the U.S., 27 times the size of designated critical habitat.

The results, published in the journal Oryx, are based on a review of 12 habitat models for jaguars within Arizona and New Mexico, conclusively identifying areas suitable for the recovery of these wild cats. Based on the expanded habitat area, the authors conclude that findings uncover new opportunities for jaguar conservation in North America that could address threats from habitat loss, climate change, and border infrastructure.

Bryan Bird, Director for Southwest Programs at Defenders of Wildlife and one of the study's co-authors, issued this statement:

"This fresh look at jaguar habitat in the U.S. identifies a much larger area that could support many more of these big cats. This expanded area of the Southwest is 27 times larger than the current designated critical habitat. We hope these findings will inspire renewed cooperation and result in more resident jaguars in the U.S."

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Background

This study was an effort from a multidisciplinary team of scientists drawing from a wealth of expertise in jaguar ecology, including members of the team that worked on the original habitat analysis for the US Fish and Wildlife Service's (FWS) jaguar recovery plan.

In this study, co-authors took the model previously developed as part of FWS' endangered jaguar recovery plan process, and applied it to all of Arizona and New Mexico, including new habitat area that was not considered in the recovery plan. Using this FWS model and additional habitat models previously done by others, the co-authors determined an area of habitat approximately the size of Rhode Island in the central mountains of Arizona and New Mexico that was not considered by the FWS in its recovery planning. The authors titled the area the "Central Arizona/New Mexico Recovery Area" (CANRA).

According to the paper, extending the area of consideration for restoration to include the CANRA and other previously overlooked smaller areas substantially raised the carrying capacity in Arizona and New Mexico, from six to as many as 151 adult jaguars, using modified models from the U.S. Fish and Wildlife Service (FWS).

This area of habitat was not considered in the jaguar recovery plan developed by FWS, released in 2019. After 50 years of discussion among FWS and state agencies about whether jaguars were part of the U.S. fauna and their management, jaguars are now federally protected as an endangered species across their range (including the U.S.), and are protected at the state level in Arizona and New Mexico.

Jaguars are usually associated with tropical habitats such as the Amazon and Central America, but historically were found as far north as the Grand Canyon. The last jaguar north of the Interstate-10 highway in Arizona was killed by a U.S. government hunter in 1964. Over the last two decades a number of male jaguars have been photographed in the mountains south of I-10 and most recently in January 2021.

Far removed from the border, the CANRA area of habitat offers new opportunities for the U.S. to contribute to the recovery of these wild cats. The expanded area identified by the co-authors includes federal, state, tribal and private lands requiring support and cooperation from all landowners. This information does not assume that jaguars would be restored on lands without landowner cooperation.

An interactive map of historical jaguar observations in the U.S. and northern Mexico is available to the public at jaguardata.info