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)
Friday, April 23, 2021
Ancient Indigenous forest gardens promote a healthy ecosystem: SFU study
The researchers say this study marks the first time forest gardens have been studied in North America
IMAGE: AN AERIAL VIEW OF A FOREST GARDEN. view more
CREDIT: SFU
A new study by Simon Fraser University historical ecologists finds that Indigenous-managed forests--cared for as "forest gardens"--contain more biologically and functionally diverse species than surrounding conifer-dominated forests and create important habitat for animals and pollinators. The findings are published today in Ecology and Society.
According to researchers, ancient forests were once tended by Ts'msyen and Coast Salish peoples living along the north and south Pacific coast. These forest gardens continue to grow at remote archaeological villages on Canada's northwest coast and are composed of native fruit and nut trees and shrubs such as crabapple, hazelnut, cranberry, wild plum, and wild cherries. Important medicinal plants and root foods like wild ginger and wild rice root grow in the understory layers.
"These plants never grow together in the wild," says Chelsey Geralda Armstrong, an SFU Indigenous Studies assistant professor and the study lead researcher. "It seemed obvious that people put them there to grow all in one spot - like a garden. Elders and knowledge holders talk about perennial management all the time."
"It's no surprise these forest gardens continue to grow at archaeological village sites that haven't yet been too severely disrupted by settler-colonial land-use."
Ts'msyen and Coast Salish peoples' management practices challenge the assumption that humans tend to overturn or exhaust the ecosystems they inhabit. This research highlights how Indigenous peoples not only improved the inhabited landscape, but were also keystone builders, facilitating the creation of habitat in some cases. The findings provide strong evidence that Indigenous management practices are tied to ecosystem health and resilience.
"Human activities are often considered detrimental to biodiversity, and indeed, industrial land management has had devastating consequences for biodiversity," says Jesse Miller, study co-author, ecologist and lecturer at Stanford University. "Our research, however, shows that human activities can also have substantial benefits for biodiversity and ecosystem function. Our findings highlight that there continues to be an important role for human activities in restoring and managing ecosystems in the present and future."
Forest gardens are a common management regime identified in Indigenous communities around the world, especially in tropical regions. Armstrong says the study is the first time forest gardens have been studied in North America -- showing how important Indigenous peoples are in the maintenance and defence of some of the most functionally diverse ecosystems on the Northwest Coast.
"The forest gardens of Kitselas Canyon are a testament to the long-standing practice of Kitselas people shaping the landscape through stewardship and management," says Chris Apps, director, Kitselas Lands & Resources Department. "Studies such as this reconnect the community with historic resources and support integration of traditional approaches with contemporary land-use management while promoting exciting initiatives for food sovereignty and cultural reflection."
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ZIT MEDICINE
Common antibiotic effective in healing coral disease lesions
FAU Harbor branch study shows 95 percent success rate with amoxicillin
VIDEO: FAU SCIENTIFIC DIVERS ERIN SHILLING AND RYAN ECKERT ARE SHOWN APPLYING THE ANTIBIOTIC TREATMENT (THE WHITE PASTE) INTO TRENCHES CREATED AROUND DISEASE LESIONS PRESENT AT THE EDGES OF THE CORAL... view more
CREDIT: JOSHUA VOSS, PH.D., FAU HARBOR BRANCH, CORAL REEF AND HEALTH ECOLOGY LAB
Diseases continue to be a major threat to coral reef health. For example, a relatively recent outbreak termed stony coral tissue loss disease is an apparently infectious waterborne disease known to affect at least 20 stony coral species. First discovered in 2014 in Miami-Dade County, the disease has since spread throughout the majority of the Florida's Coral Reef and into multiple countries and territories in the Caribbean. Some reefs of the northern section of Florida's Coral Reef are experiencing as much as a 60 percent loss of living coral tissue area.
A new study by researchers at Florida Atlantic University's Harbor Branch Oceanographic Institute reveals how a common antibiotic used to treat bacterial infections in humans is showing promise in treating disease-affected Montastraea cavernosa coral colonies in situ. M. cavernosa, also known as the Great Star Coral, is a hard or stony coral found widely throughout the tropical western Atlantic, including several regions currently affected by stony coral tissue loss disease. Preserving M. cavernosa colonies is of particular importance due to its high abundance and role as a dominant reef builder in the northern section of Florida's Coral Reef.
The objective of the study, published in Scientific Reports, was to experimentally assess the effectiveness of two intervention treatments: chlorinated epoxy and amoxicillin combined with Core Rx/Ocean Alchemists Base 2B as compared to untreated controls. Results showed that the Base 2B plus amoxicillin treatment had a 95 percent success rate at healing individual disease lesions. However, it did not necessarily prevent treated colonies from developing new lesions over time. Chlorinated epoxy treatments were not significantly different from untreated control colonies, suggesting that chlorinated epoxy treatments are an ineffective intervention technique for stony coral tissue loss disease.
"There are three possible scenarios that may explain the appearance of new lesions in the amoxicillin treated lesions of the corals that had healed in our study," said Erin N. Shilling, M.S., first author and a recent graduate of the Marine Science and Oceanography masters degree program at FAU Harbor Branch. "It's possible that the causative agent of stony coral tissue loss disease is still present in the environment and is re-infecting quiesced colonies. It also could be that the duration and dose of this antibiotic intervention was sufficient to arrest stony coral tissue loss disease at treated lesions, but insufficient at eliminating its pathogens from other areas of the coral colony."
The study was conducted approximately 2 kilometers offshore from Lauderdale-by-the-Sea in Broward County, Florida, at sites with a maximum depth of 10 meters. Both colony disease status and treated lesion status were analyzed independently so that the treatment's effectiveness at halting individual lesions could be assessed while also determining if a treatment had any impact on the colony as a whole. Colonies were monitored periodically over 11 months to assess treatment effectiveness by tracking lesion development and overall disease status.
"Success in treating stony coral tissue loss disease with antibiotics may benefit from using approaches typically successful against bacterial infections in humans, for example using a strong initial dose of antibiotics followed by a regimen of smaller supplementary doses over time," said Joshua Voss, Ph.D., senior author, an associate research professor at FAU Harbor Branch and executive director of the NOAA Cooperative Institute for Ocean Exploration, Research, and Technology. "Future research efforts should focus on assessing the potential unintended consequences of antibiotic treatments on corals, their microbial communities, and neighboring organisms. In addition, further efforts are needed to optimize dosing and delivery methods for antibiotic treatments on stony coral tissue loss disease-affected corals and scale up intervention treatments effectively."
Voss notes that many coral diseases are still poorly characterized, which has led to calls for increased research and intervention efforts to support adaptive management strategies particularly given the considerable impacts of diseases on coral reefs over the past five decades.
"Results of our experiment expand management options during coral disease outbreaks and contribute to overall knowledge regarding coral health and disease," said Voss.
This research is part of a highly coordinated collaboration through the Disease Advisory Committee (DAC) organized by the Florida Department of Environmental Protection (floridadep.gov/rcp/coral/content/stony-coral-tissue-loss-disease-response) and NOAA. Voss and Shilling are members of the DAC and part of the reconnaissance and intervention team that has collaboratively developed treatment methods, research objectives, and responses to this disease outbreak. Researchers from Nova Southeastern University, Smithsonian Marine Station and the Florida Fish and Wildlife Conservation Commission also are major partners on this team.
Ian Combs, M.S., another recent FAU graduate from Voss's lab and a co-author, helped to develop some of the coral fate-tracking techniques used in the study.
"We recommend that coral reef managers and intervention specialists, particularly those focusing on stony coral tissue loss disease, adopt 3D photogrammetric methods to ensure that data are more accurate than 2D and in-water estimates," said Combs.
CAPTION
A stony coral treated with the Base 2B plus amoxicillin treatment.
CREDIT
Joshua Voss, Ph.D., FAU Harbor Branch, Coral Reef and Health Ecology Lab
###This research was funded by the Florida Department of Environmental Protection (Awards B430E1 and B55008 awarded to Voss), and the Environmental Protection Agency (South Florida Geographic Initiative award X7 00D667-17). Additional funding was awarded to Shilling by the Harbor Branch Oceanographic Institute Foundation through the Indian River Lagoon Graduate Research Fellowship.
All work was carried out under permission of the Florida Fish and Wildlife Conservation Commission (permits SAL-18-2022-SRP and ASL-19-1702-SRP).
About Harbor Branch Oceanographic Institute:
Founded in 1971, Harbor Branch Oceanographic Institute at Florida Atlantic University is a research community of marine scientists, engineers, educators and other professionals focused on Ocean Science for a Better World. The institute drives innovation in ocean engineering, at-sea operations, drug discovery and biotechnology from the oceans, coastal ecology and conservation, marine mammal research and conservation, aquaculture, ocean observing systems and marine education. For more information, visit http://www.fau.edu/hboi.
About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 30,000 undergraduate and graduate students across six campuses located along the southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, FAU embodies an innovative model where traditional achievement gaps vanish. FAU is designated a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report and a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. For more information, visit http://www.fau.edu.
CAPTION
First author and scientific diver Erin Shilling treats a diseased stony coral affected by stony coral tissue loss disease.
CREDIT
Joshua Voss, Ph.D., FAU Harbor Branch, Coral Reef and Health Ecology Lab
Naturally GM: Crops steal genes from other species to accelerate evolution
Grass crops are able to bend the rules of evolution by borrowing genes from their neighbours, giving them a competitive advantage, a new study has revealed.
Research, led by the University of Sheffield, is the first to show that grasses can incorporate DNA from other species into their genomes through a process known as lateral gene transfer.
The stolen genetic secrets give them an evolutionary advantage by allowing them to grow faster, bigger or stronger and adapt to new environments quicker. These findings could inform future work to create crops that are more resistant to the effects of climate change and help to tackle food security problems.
The Sheffield team studied grasses, which include some of the most economically and ecologically important plants, such as the most globally cultivated crops wheat, maize, rice and barley.
Dr Luke Dunning, senior author of the research from the Department of Animal and Plant Sciences at the University of Sheffield, said: "Grasses are taking an evolutionary shortcut by borrowing genes from their neighbours. By using genetic detective work to trace the origin of each gene, we found over 100 examples where the gene had a significantly different history to the species it was found in.
"The findings may make us as a society reconsider how we view GM technology, as grasses have naturally exploited a very similar process. If we can determine how this process is happening it may allow us to naturally modify crops and make them more resistant to climate change.
"What we are seeing is not hybridisation, but the consequences are similar. Lateral gene transfer can move genetic information across wider evolutionary distances, which means it can potentially have even bigger impacts.
"Whilst only a relatively small proportion of genes are transferred between species, this process potentially allows grasses to cherry pick information from other species. This likely gives them huge advantages and may allow them to adapt to their surrounding environment quicker.
Samuel Hibdige, first author of the research and PhD Researcher from the University of Sheffield, said: "We still don't know how this is happening or what the full implications are. But, we know it is widespread in grasses, a family of plants that provide a majority of the food we eat.
"We detected foreign DNA in a wide range of grasses with all kinds of life history strategies indicating it is not restricted to those with a specific trait. However, we did detect a statistical increase in species which possess certain kinds of modified stems called rhizomes."
Since Darwin, much of our understanding of evolution has been based on the assumption that common descent is the rule for plant and animal evolution, with genetic information passed from parents to offspring.
The team's next steps will be to determine the biological mechanism behind this phenomenon and to investigate whether this is an ongoing process in crops that contributes to the differences we observe between crop varieties.
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For further information please contact: Emma Griffiths, Media and PR Assistant, University of Sheffield, 0114 222 1034, e.l.griffiths@sheffield.ac.uk
Notes to editors
The research received funding from the European Research Council (ERC), the Royal Society and the Natural Environment Research Council (NERC).
The University of Sheffield
With almost 29,000 of the brightest students from over 140 countries, learning alongside over 1,200 of the best academics from across the globe, the University of Sheffield is one of the world's leading universities.
A member of the UK's prestigious Russell Group of leading research-led institutions, Sheffield offers world-class teaching and research excellence across a wide range of disciplines.
Unified by the power of discovery and understanding, staff and students at the university are committed to finding new ways to transform the world we live in.
Sheffield is the only university to feature in The Sunday Times 100 Best Not-For-Profit Organisations to Work For 2018 and for the last eight years has been ranked in the top five UK universities for Student Satisfaction by Times Higher Education.
Sheffield has six Nobel Prize winners among former staff and students and its alumni go on to hold positions of great responsibility and influence all over the world, making significant contributions in their chosen fields.
Global research partners and clients include Boeing, Rolls-Royce, Unilever, AstraZeneca, Glaxo SmithKline, Siemens and Airbus, as well as many UK and overseas government agencies and charitable foundations
Plant provenance influences pollinators
Researchers study the importance of interactions between plants and insects in the restoration of ecosystems
IMAGE: EARTH BUMBLEBEE COVERED WITH POLLEN FROM FIELD SCABIOUS. view more
CREDIT: WWU - PETER LESSMANN
Insect decline is one of the greatest challenges facing our society. As a result of the destruction of many natural habitats, bees, bumblebees, butterflies, beetles and the like find less and less food. As a consequence, they are barely able to fulfil their role as pollinators of wild and cultivated plants. This trend is increasingly noticeable in agricultural regions in particular.
Researchers at the University of Münster have now taken a more detailed look at how the choice of seeds in restoration measures - i.e. the restoration of natural habitats at degraded land - affects how insects benefit from these measures. Here, not only the plant species plays an important role, but so does the geographical provenance of the seeds used - because the provenance influences not only insect diversity but also how often the pollinators visit flowers. The results of the study have been published in the "Journal of Applied Ecology".
Background and methodology
Insects are indispensable for the functioning of ecosystems - and for human survival. They are necessary, for example, for the pollination of many cultivated plants which are, in turn, an essential source of nutrition for humans. In regions characterized by agriculture or in built-up areas with settlements and cities, there are reduced resources available to pollinators. In order to support them in their pollination, flower-rich habitats are created in the landscape, often in the form of wildflower stripes.
When flower stripes or other habitats are created, however, it should be taken into account that plant species are not homogeneous entities, as their populations genetically differ. This differentiation often occurs as a result of population adaptation to their local environment. A brown knapweed, for example, which grows near the sea - where frost is rare - will be less frost-resistant than a brown knapweed which grows in the mountains, where frost is common. The differences can be seen in many plant traits, and some of these differences can influence pollinators, for example the number of flowers or the time when they flower. "Depending on the provenance, some populations flower earlier than others," as Dr. Anna Lampei Bucharová from Münster University's Institute of Landscape Ecology explains, who also lead the study. "When setting up habitats for pollinators, these within-species differences have so far often been neglected," she adds, "and the plants are mostly selected regardless of their provenance. This is why we tested to see whether the provenance of the plants influences pollinators."
The geographical provenance of the seeds plays a key role in this context. In a field experiment, the researchers formed small experimental plant communities which had exactly the same species composition but different provenances. The populations came from the Münster region, from the area around Munich and from greater Frankfurt an der Oder. They then recorded flowering data, observed the pollinators visiting these communities, and compared the frequency and diversity of the pollinators in communities with different provenances.
The researchers discovered that a plant's provenance influences pollinators - both how often the pollinators visit flowers and also the diversity of the insect species. "The effect can be considerable," says Dr. David Ott, co-author of the study. "We observed twice as many visits by pollinators at flowers of one provenance than at flowers of another provenance. The most important parameter driving this is the phenology of the plant's flower - in other words, the temporal sequence of flowering," he adds. The researchers conclude that plants from some provenances started to flower earlier and more intensively than others, and so they presented more flowers and, as a result, interacted more frequently with pollinators.
The results are important both for scientists and for ecological restoration. The researchers are confident that Germany provides good conditions for implementing provenance-based restoration strategies, because regional ecotypes of many species are readily available in the so-called "Regiosaatgut" ("regional seeds") system. This system provides regional seeds for many species for up to 22 regions in Germany. Thus, by selecting the appropriate plant origins, resources for pollinators could be sustainably improved.
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Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.
As part of the Paris Agreement, nearly all countries agreed to take steps to limit the average increase in global surface temperature to less than 2 °C, or preferably 1.5 °C, compared with preindustrial levels. Since the Agreement was adopted, however, concerns about global warming suggest that countries should aim for the "preferable" warming limit of 1.5 °C.
What are the implications for China of trying to achieve this lower limit?
Prof. DUAN Hongbo from the University of Chinese Academy of Sciences and Prof. WANG Shouyang from the Academy of Mathematics and Systems Science of the Chinese Academy of Sciences, together with their collaborators, have attempted to answer this question.
Their results were published in an article entitled "Assessing China's efforts to pursue the 1.5°C warming limit," which was published in Science on April 22.
The authors used nine different integrated assessment models (IAMs) to make their evaluation of China's effort to achieve the warming limit of 1.5 °C.
The various models show different emission trajectories for carbon and noncarbon emissions. The majority of the IAMs will achieve near-zero or negative carbon emissions by around 2050, with a range from -0.13 billion tonnes of CO2 (GtCO2) to 2.34 GtCO2 across models. However, one highly consistent finding among all models is that the 1.5°C warming limit requires carbon emissions decrease sharply after 2020.
The researchers discovered that a steep and early drop in carbon emissions reduces dependency on negative emission technologies (NETs), i.e., technologies that capture and sequester carbon. One implication of this finding is that there is a trade-off between substantial early mitigation of carbon emissions and reliance on NETs, which may have uncertain performance. At the same time, the model showing the lowest carbon emissions by 2050 shows the greatest reliance on carbon capture and storage (CCS) technology--suggesting that NETs have an important role in reducing carbon emissions.
Although carbon emissions were an important focus of the study, the researchers also noted that reducing noncarbon emissions is necessary to stay under the warming limit. Specifically, carbon emissions must be reduced by 90%, CH4 emissions by about 71% and N2O emissions by about 52% to achieve the 1.5 °C goal.
The study showed that mitigation challenges differ across sectors, e.g., industry, residential and commercial, transportation, electricity and "other." Among these sectors, industry plays a big role in end-use energy consumption. Therefore, substantial changes in industrial energy use must occur to reach deep decarbonization of the entire economy and realization of the given climate goals. Indeed, a highly consistent finding across all models is that the largest proportion of emission reduction will come from a substantial decline in energy consumption.
The study also highlights the importance of replacing fossil fuels with renewables, a strategy that plays the next most important role in emission reduction behind reducing energy consumption. The study suggests that China needs to decrease its fossil energy consumption (as measured by standard coal equivalent, or Gtce) by about 74% in 2050 in comparison with the no policy scenario.
The researchers estimate that achieving the 1.5 °C goal will involve a loss of GDP in 2050 in the range of 2.3% to 10.9%, due to decreased energy consumption and other factors.
The study also noted that China's recently announced plan to become carbon neutral by 2060 largely accords with the 1.5 °C warming limit; however, achieving the latter goal is more challenging.
China requires switch to zero-carbon energy to achieve more ambitious Paris Agreement goal, models S
AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE
A new multi-model analysis suggests that China will need to reduce its carbon emissions by over 90% and its energy consumption by almost 40%, in order to meet the more ambitious target set by the 2016 Paris Agreement. The Agreement called for no more than a 1.5°Celsius (C) global temperature rise by 2050. These results provide a clear directive for China to deploy multiple strategies at once for long-term emission mitigation, the authors say. The findings also highlight the need for more research on the economic consequences of working toward a 1.5°C warming limit, arguing that current studies are far from adequate to inform the sixth assessment report (AR 6) on climate change planned for release by the United Nations' Intergovernmental Panel on Climate Change in 2022. Most research to inform climate policy has centered on the goal of 2.0°C, and to date, "there is clearly no consensus on the attractiveness of a 1.5°C target, particularly given the uncertainty in associated mitigation costs," say Hongbo Duan and colleagues. To help fill in this gap, Duan et al. used multiple climate models to assess how China might attain this goal by mid-century. All models consistently showed that of all sectors, industry is the main emission contributor, and the power sector would need to achieve full decarbonization to meet the 1.5°C goal by 2050. Negative emission technologies would play an important role in the achievement of near-zero emissions, with captured carbon accounting on average for 20% of total reductions by 2050. Furthermore, the researchers found that the cost of policies to attain this goal may amount to 2.8% to 5.7% of China's gross domestic product by 2050. For future work, the authors note the need for improving representation of technology and climate-associated economic damage in future climate models.
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Political polarization: Often not as bad as we think
COLUMBIA UNIVERSITY'S MAILMAN SCHOOL OF PUBLIC HEALTH
As politics grows increasingly polarized, a new global study finds people often exaggerate political differences and negative feelings of those on the opposite side of the political divide, and this misperception can be reduced by informing them of the other side's true feelings. The study replicates earlier research in the United States, finding the phenomenon to be generalizable across 25 countries.
The new study was led by Kai Ruggeri, PhD, assistant professor of health policy and management at Columbia University Mailman School of Public Health, and replicates a 2020 study by Jeffrey Lees and Mina Cikara at Harvard University, who were also co-authors of the new study. The new findings appear in the journal Nature Human Behaviour.
The Lee and Cikara study presented five political scenarios (e.g. banning anonymous political donations or changing the name given to the state highway) whereby one group proposes a change in law or policy which could disadvantage the other political party (Democrat or Republican). The new study replicated experiments from the original paper, testing the findings in 10,207 participants, following the original methodology as closely as possible and adapting group divisions and scenarios to the local political context for each of the other countries. For example, in Canada, they asked participants to respond to proposed changes to the way voting districts are defined; in Sudan, participants considered changes to the way water tariffs are calculated.
Says Ruggeri: "Our study provides evidence that people around the world overestimate the negative feelings of their political opponents, when in fact the other side is often much less negative than the perceptions we harbor about the other group. These misperceptions have real-world consequences, from polarization, intergroup conflict, and increasingly aggressive narratives in traditional and social media.
"While differences between the beliefs and actions of opposing political parties undoubtedly exist--particularly on widely covered issues like gun ownership or access to reproductive healthcare--their opinions on less reported issues are often more similar than we think. The findings from our study suggest that focusing on issues without making them partisan matters, while also presenting accurate representations of group beliefs, can directly mitigate the exaggeration of polarization," he adds.
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The study is a collaboration between 82 authors from 42 institutions; as well as 16 interns and 43 alumni from the Junior Researcher Programme, a global initiative for early career researchers in the behavioral sciences partnering with Columbia Global Programs; 14 students from the Global Scholars Programme in Europe: Global Behavioral Science (GLOBES); and other volunteers.
The future looks bright for infinitelyrecyclable plastic
A new environmental and technological analysis suggests that a revolutionary eco-friendly plastic is almost ready to hit the shelves
IMAGE: BRETT HELMS, FOREGROUND, PICTURED AT WORK IN THE MOLECULAR FOUNDRY IN 2019. view more
CREDIT: (CREDIT: THOR SWIFT/BERKELEY LAB)
Plastics are a part of nearly every product we use on a daily basis. The average person in the U.S. generates about 100 kg of plastic waste per year, most of which goes straight to a landfill. A team led by Corinne Scown, Brett Helms, Jay Keasling, and Kristin Persson at Lawrence Berkeley National Laboratory (Berkeley Lab) set out to change that.
Less than two years ago, Helms announced the invention of a new plastic that could tackle the waste crisis head on. Called poly(diketoenamine), or PDK, the material has all the convenient properties of traditional plastics while avoiding the environmental pitfalls, because unlike traditional plastics, PDKs can be recycled indefinitely with no loss in quality.
Now, the team has released a study that shows what can be accomplished if manufacturers began using PDKs on a large scale. The bottom line? PDK-based plastic could quickly become commercially competitive with conventional plastics, and the products will get less expensive and more sustainable as time goes on.
"Plastics were never designed to be recycled. The need to do so was recognized long afterward," explained Nemi Vora, first author on the report and a former postdoctoral fellow who worked with senior author Corinne Scown. "But driving sustainability is the heart of this project. PDKs were designed to be recycled from the get-go, and since the beginning, the team has been working to refine the production and recycling processes for PDK so that the material could be inexpensive and easy enough to be deployed at commercial scales in anything from packaging to cars."
The study presents a simulation for a 20,000-metric-ton-per-year facility that puts out new PDKs and takes in used PDK waste for recycling. The authors calculated the chemical inputs and technology needed, as well as the costs and greenhouse gas emissions, then compared their findings to the equivalent figures for production of conventional plastics.
"These days, there is a huge push for adopting circular economy practices in the industry. Everyone is trying to recycle whatever they're putting out in the market," said Vora. "We started talking to industry about deploying 100% percent infinitely recycled plastics and have received a lot of interest."
"The questions are how much it will cost, what the impact on energy use and emissions will be, and how to get there from where we are today," added Helms, a staff scientist at Berkeley Lab's Molecular Foundry. "The next phase of our collaboration is to answer these questions."
Checking the boxes of cheap and easy
To date, more than 8.3 billion metric tons of plastic material have been produced, and the vast majority of this has ended up in landfills or waste incineration plants. A small proportion of plastics are sent to be recycled "mechanically," meaning they are melted down and then re-shaped into new products. However, this technique has limited benefit. Plastic resin itself is made of many identical molecules (called monomers) bound together into long chains (called polymers). Yet to give plastic its many textures, colors, and capabilities, additives like pigments, heat stabilizers, and flame retardants are added to the resin. When many plastics are melted down together, the polymers become mixed with a slew of potentially incompatible additives, resulting in a new material with much lower quality than newly produced virgin resin from raw materials. As such, less than 10% of plastic is mechanically recycled more than once, and recycled plastic usually also contains virgin resin to make up for the dip in quality.
PDK plastics sidestep this problem entirely - the resin polymers are engineered to easily break down into individual monomers when mixed with an acid. The monomers can then be separated from any additives and gathered to make new plastics without any loss of quality. The team's earlier research shows that this "chemical recycling" process is light on energy and carbon dioxide emissions, and it can be repeated indefinitely, creating a completely circular material lifecycle where there is currently a one-way ticket to waste.
Yet despite these incredible properties, to truly beat plastics at their own game, PDKs also need to be convenient. Recycling traditional petroleum-based plastic might be hard, but making new plastic is very easy.
"We're talking about materials that are basically not recycled," said Scown. "So, in terms of appealing to manufacturers, PDKs aren't competing with recycled plastic - they have to compete with virgin resin. And we were really pleased to see how cheap and how efficient it will be to recycle the material."
Scown, who is a staff scientist in Berkeley Lab's Energy Technologies and Biosciences Areas, specializes in modeling future environmental and financial impacts of emerging technologies. Scown and her team have been working on the PDK project since the outset, helping Helms' group of chemists and fabrication scientists to choose the raw materials, solvents, equipment, and techniques that will lead to the most affordable and eco-friendly product.
"We're taking early stage technology and designing what it would look like at commercial-scale operations" using different inputs and technology, she said. This unique, collaborative modeling process allows Berkeley Lab scientists to identify potential scale-up challenges and make process improvements without costly cycles of trial and error.
The team's report, published in Science Advances, models a commercial-scale PDK production and recycling pipeline based on the plastic's current state of development. "And the main takeaways were that, once you've produced the PDK initially and you've got it in the system, the cost and the greenhouse gas emissions associated with continuing to recycle it back to monomers and make new products could be lower than, or at least on par with, many conventional polymers," said Scown.
Planning to launch
Thanks to optimization from process modeling, recycled PDKs are already drawing interest from companies needing to source plastic. Always looking to the future, Helms and his colleagues have been conducting market research and meeting with people from industry since the project's early days. Their legwork shows that the best initial application for PDKs are markets where the manufacturer will receive their product back at the end of its lifespan, such as the automobile industry (through trade-ins and take-backs) and consumer electronics (through e-waste programs). These companies will then be able to reap the benefits of 100% recyclable PDKs in their product: sustainable branding and long-term savings.
"With PDKs, now people in industry have a choice," said Helms. "We're bringing in partners who are building circularity into their product lines and manufacturing capabilities, and giving them an option that is in line with future best practices."
Added Scown: "We know there's interest at that level. Some countries have plans to charge hefty fees on plastic products that rely on non-recycled material. That shift will provide a strong financial incentive to move away from utilizing virgin resins and should drive a lot of demand for recycled plastics."
After infiltrating the market for durable products like cars and electronics, the team hopes to expand PDKs into shorter-lived, single-use goods such as packaging.
A full circle future
As they forge plans for a commercial launch, the scientists are also continuing their techno-economic collaboration on the PDK production process. Although the cost of recycled PDK is already projected to be competitively low, the scientists are working on additional refinements to lower the cost of virgin PDK, so that companies are not deterred by the initial investment price.
And true to form, the scientists are working two steps ahead at the same time. Scown, who is also vice president for Life-cycle, Economics & Agronomy at the Joint BioEnergy Institute (JBEI), and Helms are collaborating with Jay Keasling, a leading synthetic biologist at Berkeley Lab and UC Berkeley and CEO of JBEI, to design a process for producing PDK polymers using microbe-made precursor ingredients. The process currently uses industrial chemicals, but was initially designed with Keasling's microbes in mind, thanks to a serendipitous cross-disciplinary seminar.
"Shortly before we started the PDK project, I was in a seminar where Jay was describing all the molecules that they could make at JBEI with their engineered microbes," said Helms. "And I got very excited because I saw that some of those molecules were things that we put in PDKs. Jay and I had a few chats and, we realized that nearly the entire polymer could be made using plant material fermented by engineered microbes."
"In the future, we're going to bring in that biological component, meaning that we can begin to understand the impacts of transitioning from conventional feedstocks to unique and possibly advantaged bio-based feedstocks that might be more sustainable long term on the basis of energy, carbon, or water intensity of production and recycling," Helms continued. "So, where we are now, this is the first step of many, and I think we have a really long runway in front of us, which is exciting."
CAPTION
A GIF showing how PDK plastic readily breaks down when put in an acidic solution. The acid helps to break the bonds between the monomers and separate them from the chemical additives that give plastic its look and feel.
CREDIT
(Credit: Peter Christensen/ Berkeley Lab)
The Molecular Foundry is a Department of Energy (DOE) Office of Science user facility that specializes in nanoscale science. JBEI is a Bioenergy Research Center funded by DOE's Office of Science.
This work was supported by the DOE's Bioenergy Technologies Office and Berkeley Lab's Laboratory Directed Research and Development (LDRD) program.
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Climate-smart ag strategies may cut nitrous oxide emissions from corn production
IMAGE: LEAD RESEARCHER MARIA PONCE DE LEON, A FORMER GRADUATE STUDENT IN PLANT SCIENCE, CARRIES A NITROUS OXIDE EMISSIONS CHAMBER INTO A CORN FIELD AT PENN STATE'S RUSSELL E. LARSON AGRICULTURAL... view more
CREDIT: HEATHER KARSTEN, PENN STATE
For corn, using dairy manure and legume cover crops in crop rotations can reduce the need for inorganic nitrogen fertilizer and protect water quality, but these practices also can contribute to emissions of nitrous oxide -- a potent greenhouse gas.
That is the conclusion of Penn State researchers, who measured nitrous oxide emissions from the corn phases of two crop rotations -- a corn-soybean rotation and a dairy forage rotation -- under three different management regimens. The results of the study offer clues about how dairy farmers might reduce the amount of nitrogen fertilizer they apply to corn crops, saving money and contributing less to climate change.
The results are important because although nitrous oxide accounts for just 7% of U.S. greenhouse gas emissions, it is significantly more potent than carbon dioxide or methane when it comes to driving climate change, according to Heather Karsten, associate professor of crop production/ecology in the College of Agricultural Sciences. Nitrous oxide is almost 300 times more powerful than carbon dioxide and remains in the atmosphere for more than 100 years.
"This research suggests that all nitrogen inputs -- manure, legumes and fertilizer -- contribute to nitrous oxide emissions," she said. "But farmers could reduce nitrous oxide emissions if they could apply manure after the crop is planted, closer to when the corn begins to take up nitrogen.
"And if they could apply manure only when the crop needs it by "side-dressing," she added, "they likely could use less inorganic nitrogen fertilizer. But equipment for side-dressing manure into a growing corn crop is not yet widely available."
Researchers compared the effects of three management treatments for no-till corn and measured nitrous oxide emissions throughout the corn growing season. In the corn-soybean rotation, the team compared nitrous oxide emissions from broadcasting dairy manure, shallow disk manure injection, and the application of inorganic fertilizer in the form of liquid urea ammonium nitrate.
Manure was applied before corn was planted, as most farms do, while in the inorganic fertilizer treatment, fertilizer was applied according to recommended practices -- when the corn was growing and taking up nitrogen.
This better timing for nitrogen application allowed for a reduced total nitrogen application, and the nitrous oxide emissions were lower than with the injected manure treatment. Injecting manure increased nitrous oxide emissions compared to the broadcast manure treatment in one year of the study, indicating that the environmental and nitrogen-conservation benefits of injection should be weighed against the additional emissions when selecting the practice.
The researchers also compared nitrous oxide emissions from corn grown for silage or grain in the no-till, six-year, dairy forage rotation in which corn followed a two-year, mixed alfalfa and orchardgrass forage crop and also a crimson clover cover crop. Manure also was broadcasted before corn planting, and nitrous oxide emissions were compared to the rotation in which corn was planted after soybean with broadcast manure. The nitrous oxide emissions during the corn season didn't differ among the three prior legume treatments.
In both experiments, nitrous oxide emissions peaked a few weeks after manure was applied and for a short period after fertilizer was applied. Since nitrous oxide emissions are influenced by factors that influence microbial processes, the researchers examined what environmental and nitrogen-availability factors were most predictive of nitrous oxide emissions. Increasing temperatures spurring corn growth and factors that influence soil nitrogen availability were important factors in both comparisons.
The study shows that nitrogen availability from organic inputs such as manure and legume cover crops can contribute to nitrous oxide emissions from corn, noted lead researcher Maria Ponce de Leon, former graduate student in Karsten's research group, now a doctoral candidate at the University of California, Davis. Identifying how to time organic nitrogen amendments with corn uptake represents an opportunity, she said, to reduce nitrous oxide emissions from dairy production systems.
Now, dairy farmers apply manure mostly prior to planting corn, and as the manure and the organic legume biomass from the cover crop decompose, the nitrogen content builds in the soil. Some of it can be lost as nitrous oxide emissions or leach into groundwater.
"Until the corn is rapidly taking up nitrogen from the soil, there's potential for both of those environmental losses," Ponce de Leon said. "If we could better synchronize the timing of the manure application to when the corn is growing and taking up nitrogen, we could reduce nitrous oxide missions. That also would help the crop and the farmer better capture the nitrogen that's available in that manure."
CAPTION
Using measuring chambers like those shown here, researchers found that nitrous oxide emissions peaked a few weeks after manure was applied and for a short period after fertilizer was applied. Identifying how to time organic nitrogen amendments with corn uptake represents an opportunity to reduce nitrous oxide emissions from dairy production systems, the researchers said.
CREDIT
Maria Ponce de Leon, Penn State
The research, recently published in Nutrient Cycling in Agroecosystems, was conducted at Penn State's Russell E. Larson Agricultural Research Center as part of the much larger "Dairy Cropping Systems" project that has been underway for more than a decade. Initiated in 2010, that parent project aims to sustainably produce the forage and feed for a typical 65-cow, 240-acre dairy farm in Pennsylvania.
Curtis Dell, soil scientist with the U.S. Department of Agriculture's Agricultural Research Service Pasture Systems and Watershed Management Research Unit, contributed to the research.
The U.S. Department of Agriculture supported this work.
