Cover crop could solve weed problems for edamame growers

by Lauren Quinn, University of Illinois at Urbana-Champaign
  

Credit: CC0 Public Domain

For vegetable growers, weeds can mean lost income from reduced yield and foreign plant matter contaminating the harvest. But for many crops, particularly vegetable legumes, weed management options are very limited.

Cover crops such as cereal rye reduce weed competition in grain soybean, but most vegetable legume growers have yet to adopt the practice due to the potential for reduced germination and yield in thick cover crop residue. However, a new study from the University of Illinois and USDA Agricultural Research Service (USDA-ARS) shows early-terminated rye could be a promising part of an integrated weed management program for some vegetable legumes, including edamame.

"In general, the more cover crop biomass you have, the better the weed suppression. We found a sweet spot in an earlier experiment with edamame when we terminated rye at tillering and then planted into the stubble. The rye provided measurable weed suppression without harming the crop," says Marty Williams, USDA-ARS ecologist and affiliate professor in the Department of Crop Sciences at Illinois. "We wanted to follow that up with yield experiments for edamame, and decided to broaden to some mainstream vegetable legumes including snap bean and lima bean."

Williams and his research team looked at weed density and biomass in bare soil and in plots planted with a rye cover crop terminated at tillering, about a month before vegetable crops were planted. For three growing seasons, the researchers either sprayed weeds with one of the few registered herbicides; hand-pulled weeds in addition to spraying; or left weeds alone to grow. Then they gathered information on weed suppression, crop establishment and yield, as well as soil moisture and nitrogen.

In edamame and snap bean, early-terminated rye reduced weed biomass by 53% and 73%, respectively, compared with bare soil. And, consistent with his earlier studies, Williams found no reductions in edamame establishment or yield. Yet, the results for snap bean and lima bean were not as rosy. Both lost yield when planted in rye residue, and weed density and biomass actually increased for lima bean, compared with bare soil.

"We found the early-terminated rye system worked well in edamame. The rye suppressed weed biomass without impacting the crop." Williams says. "For lima bean, the system failed. For snap bean, there is room for improvement."

He suspects the poor performance in lima and snap bean is related to the crops' weak ability to fix nitrogen in soils depleted of the nutrient by the cover crop. In turn, poor crop growth and canopy development favored the weeds.

"We had a problem with crop establishment in lima bean in the rye stubble," Williams says. "And while snap bean established well, crop growth was hampered by the nitrogen-starved environment in rye stubble—one of the key traits providing weed suppression."

Edamame, like soybean, can grow without applied nitrogen because it benefits from symbiosis with nitrogen-fixing bacteria. Williams' group is currently doing follow-up research to exploit biological nitrogen fixation in snap bean, which would have implications beyond weed management.

Although early-terminated rye worked well in edamame, the cover crop didn't eliminate the need for other weed control measures.

"Early-terminated rye alone is not going to solve all weed problems," Williams says. "It reduced the weed load, but did not eliminate it. Early-terminated rye roughly halved the weeds compared to bare soil. The weed load was further reduced by using an herbicide, too. Hand-weeding, while generally used as a last-resort tactic, was used in this system to entirely eliminate interference with the crop and weed seedbank additions. That combination is the most effective approach."


Early-killed rye shows promise in edamame
More information: Nicholas E. Korres et al, Integrated weed management strategies with cereal rye mulch in processing vegetable legumes, Agronomy Journal (2020). DOI: 10.1002/agj2.20349
Journal information: Agronomy Journal
Provided by University of Illinois at Urbana-Champaign

How psychological ownership can enhance stewardship for public goods

THE DIFFERENCE BETWEEN BEING 

A CUSTODIAN OR A JANITOR

by Kim Tucker Campo, New York Institute of Technology

Credit: CC0 Public Domain

How can consumers be encouraged to take better care of public goods and resources? That's the question posed in a new research paper co-authored by Colleen P. Kirk, D.P.S., associate professor of marketing at New York Institute of Technology, in the Journal of Marketing.

"Caring for the Commons: Using Psychological Ownership to Enhance Stewardship Behavior for Public Goods" aims to help solve the "tragedy of the commons," the idea that when goods or resources are shared by many owners they are subject to abuse or neglect.

Sadly, the tragedy of the commons can be seen in many public spaces, such as cemeteries, public housing, fishing areas, and beaches, and has contributed to a number of environmental challenges. One commonly cited environmental issue includes ocean pollution. Because ocean waters are shared by many different nations no single authority has the power to pass laws that protect the entire ocean. Instead, nations manage and protect ocean resources along their coastlines, leaving the much larger shared waters vulnerable to contamination.

Citing available studies on the tragedy of the commons, Kirk joins Joann Peck, Ph.D., of Wisconsin-Madison School of Business; Andrea Luangrath, Ph.D., of the University of Iowa; and Suzanne Shu, Ph.D., of Cornell University in hypothesizing that increased feelings of ownership towards a public good can help ensure that individuals do their part.

Putting their theory to the test

The researchers manipulated scenarios in public settings to encourage visitors to view the spaces as their own, rather than as a shared commodity. In each scenario, the investigators found that increasing psychological ownership enhanced stewardship, causing participants to become more likely to take direct action to care for that setting, such as picking up trash, or financial stewardship, such as donating money.

For example, the researchers manipulated psychological ownership of a lake by asking a randomized group of kayak renters to think of and write down a nickname for the lake before renting their boats. Unbeknownst to the kayakers, the researchers had planted anchored floating trash in the lake to test whether naming the lake would create an increased feeling of ownership. Compared to the control group, kayakers who were not asked to name the lake, the "namers" were more likely to do their part in trying to pick up the trash, with 41 percent attempting to remove the planted litter.


In another scenario, study participants were asked to imagine that they were taking a walk in a hypothetical park called Stoneview Park. Researchers showed the control group a park entrance sign that read the generic message, "Welcome to the park." In contrast, the experimental group was shown a sign reading, "Welcome to YOUR park." Each group of "walkers" then completed a survey on how likely they were to remove litter or donate to park maintenance efforts. Once again, when compared to the control group, those exposed to the psychological ownership tactics (YOUR park group) felt a greater need to care for and contribute to maintaining the public space.

A third scenario tested yet another psychological ownership tactic aimed at cultivating stewardship. Cross country skiers and snowshoers at a public park ski rental were asked to plan a route prior to their outing. Following the completion of the park's standard liability waiver, an employee offered them a map, obtained their shoe size, and, in the control group (the "non-planners"), went on to retrieve the ski equipment. However, in the experimental group, before retrieving the skis or snowshoes, the employee asked the renters to plan a route they might take on the map. All renters were then charged for their ski equipment and asked whether they would like to add a dollar to the rental fee to help the park. Donations indicated that individuals who planned their route in advance were more likely to chip in. In addition, a participant survey also revealed that those asked to plan their route were more likely to feel ownership, volunteer, donate in the future, and promote the park to others using social media. The researchers believe that because these skiers played an active role in shaping their experience, they may have felt a greater sense of connection to the park.

Kirk, who has published significant research on psychological ownership and an op-ed in Harvard Business Review, believes the findings can assist marketers in conservation efforts.

"Maintaining the natural environment is a pressing issue facing our planet, and has become more challenging during the pandemic as park services are reduced while the number of people spending time outside has increased," she notes. "Researchers have previously shown that eliciting feelings of ownership in consumers, even in the absence of legal ownership, induces them to value a product more highly. In this research, we document, through a variety of experimental studies in the field and in the laboratory, that individual psychological ownership also motivates caring behaviors for a public good, such as picking up trash from a lake or donating time or money to a park. We encourage marketers and environmentalists alike to reflect on these findings when considering ways to maintain public spaces."


Why people go into debt: The money isn't really theirs
More information: Joann Peck et al, Caring for the Commons: Using Psychological Ownership to Enhance Stewardship Behavior for Public Goods, Journal of Marketing (2020). DOI: 10.1177/0022242920952084
Journal information: Journal of Marketing
Provided by New York Institute of Technology

The Pentecostal movement seeks a healthier form of community
IMPERIALISM THE HIGHEST FORM OF PROTESTANTISM
by University of Helsinki

Credit: CC0 Public Domain

Pentecostalism is the largest and fastest growing branch of Christianity in the world after the Catholic Church. Thanks to its focus on missionary work, Pentecostalism wields significant power particularly in areas where western secular culture has not gained dominant status, sch as in many parts of Africa.

"It's also a major political and social movement. Pentecostal demonology views demons as active agents with the power to influence people and various aspects of their daily lives. Other Christian denominations see this as problematic, as it tends to generate unhealthy phenomena and can result in practices and interpretations that are ethically problematic," explains Sanna Urvas, a doctoral candidate at the Faculty of Theology in University of Helsinki, Finland.

"In many African countries and places such as Papua New Guinea, witchcraft is a part of the traditional culture, but the Christian interpretation sees it as the work of evil spirits. Accusations of witchcraft are typically leveled at women, young people or the poor."

Evil comes from people, not demons

Theologians Amos Yong from the USA and Opoku Onyinah from Ghana are trying to reform Pentecostal thinking and its understanding of sin and evil.

"Yong's approach is exceptional in the Pentecostal context, as he accuses people and communities of evil, instead of demons. This means that evil could be banished by renouncing corruption and unhealthy power structures while protecting the weak, for example."

Onyinah emphasizes the significance of people's personal choices and the responsibilities of the communities instead of blaming misfortune on witchcraft perpetrated by a neighbor," Sanna Urvas describes.

"Both Yong and Onyinah are producing theology that aims at improving the lives of these communities. Both of them protect the underdog by highlighting unfair practices and undoing interpretations that enable abuses of power. Both unequivocally condemn teachings that claim a Christian might be possessed by a demon.

Demonology infringes on human rights

According to Sanna Urvas, belief in demonic possession enables psychological and spiritual violence while polarizing communities.

"Based on studies conducted in Africa, interpreting developmental disabilities as demonic has significantly eroded the human rights of disabled people and reduced their agency. Various illnesses, such as depression, may also be seen as the fault of spirits. This causes significant psychological stress for the disabled or sick person as well as their family."

Claiming that anything out of the ordinary, such as dissident thought, is demonic in nature may also lead to human rights violations.

According to Urvas, various activities across the denominational lines have brought demonological interpretations to nearly all denominations.

"The issue of demonic possession is controversial in the churches and fellowships outside the mainline denominations. Classical Pentecostalism teaches that the sick can be healed through prayer. A constructive interpretation of this would be that the sick person receives support and believes that God can heal them miraculously. Refusal of medical interventions and resorting to exorcisms are more disturbing phenomena. The goal of my research is, among other things, to emphasize an understanding of the underlying causes of illness that combines a medical standpoint with the belief in a healing God. This way, the sick person will receive the best help modern medicine can provide while still benefitting from the psychological and spiritual support of others praying for them. Such an integrated understanding should be embraced throughout the Pentecostal Church and potentially even more broadly."

Women as equal theological authorities

Pentecostalism is a very patriarchal movement, both in Finland and elsewhere. At The Church of Pentecost in Ghana, which is the second case study in Sanna Urvas's research, women are not allowed to study theology or serve as pastors.

"Also in Finland, the Pentecostal Church has very few female theological authorities. It seems I'm the first Pentecostal woman to receive a doctorate in systematic theology at a research university while specializing in Pentecostal theology. Meeting the women in the Ghanaian church was a revelation for them: a woman can also be a doctrinal authority."

Urvas wants to empower all women in the Pentecostal church in Finland and elsewhere:

"We as women have equal rights and opportunities to build healthier beliefs and practices and therefore communities everywhere in the world."

Sanna Urvas, MTh and MA (Dance), will defend her doctoral thesis entitled Theology of sin and evil in Classical Pentecostalism—Two case studies at the University of Helsinki's Faculty of Theology on 16 October 2020 at 2pm. Docent Jaakko Rusama from the University of Helsinki will serve as the opponent and Professor Risto Saarinen as the custos.


Nearly half of Finnish pastors have a positive attitude towards euthanasia
Provided by University of Helsinki

Sea star's ability to clone itself may empower this mystery globetrotter

by Smithsonian Tropical Research Institute

Mystery solved: the mystery larvae collected in the Caribbean grow up to become this sea star, Valvaster striatus, which is only known from the Indo Pacific region. Credit: Gustav Paulay

For decades, biologists have captured tiny sea star larvae in their nets that did not match the adults of any known species. A Smithsonian team recently discovered what these larvae grow up to be and how a special superpower may help them move around the world. Their results are published online in the Biological Bulletin.


"Thirty years ago, people noticed that these asteroid starfish larvae could clone themselves, and they wondered what the adult form was," said staff scientist Rachel Collin at the Smithsonian Tropical Research Institute (STRI). "They assumed that because the larvae were in the Caribbean the adults must also be from the Caribbean."

Scientists monitor larvae because the larvae can be more sensitive to physical conditions than the adults and larval dispersal has a large influence on the distribution of adult fishes and invertebrates. Collin's team uses a technique called DNA barcoding to identify plankton. They determine the DNA sequence of an organism, then look for matches with a sequence from a known animal in a database.

"This mystery species was one of the most common in our samples from the Caribbean coast of Panama," Collin said. "We knew from people's studies that the DNA matched sequences from similar larvae across the Caribbean and it matched unidentified juvenile starfish caught in the Gulf of Mexico—but no one had found a match to any known adult organism in the Caribbean. So we decided to see if the DNA matched anything in the global 'Barcode of Life' data base."

For thirty years, scientists have been capturing these larvae in their plankton nets, but only now have they discovered what they are. The larvae have the ability to make copies of themselves--clones. Credit: Michael Boyle

"That's when we got a match with Valvaster striatus, a starfish that was thought to be found only in the Indo West Pacific," Collin said. "The is the first-ever report of this species in the Atlantic Ocean. We could not have identifed it if Gustav Paulay from the University of Florida didn't have DNA sequences from invertebrates on the other side of the world."

But why are the larvae common in the Caribbean if adult Valvaster starfish have never been found here? Are the adult starfish hidden inside Caribbean reefs, or are the larvae arriving from the other side of the world?

V. striatus is widespread but rare in the western Pacific. The few reports from collectors and the confirmed photos on iNaturalist range from the Indian Ocean to Guam and Hawaii. These starfish live deep in the reef matrix, only coming out at night. So, it is possible that there are adults in the Caribbean that have never been seen. But the other possibility, that the ability to clone themselves may allow them to spread around the world, is also intriguing.

"It's possible that the ability of the larvae to clone themselves is not just a clever way to stay forever young," Collin said. "There's a natural barrier that keeps organisms from the western Pacific and the Indian ocean from crossing the Atlantic to the Caribbean. After they make it around the tip of Africa, they are met by a cold current that presumably kills tropical species."

"Just how cloning could help them get through the barrier is still not known, but it's intriguing that another sea star species from the Indo West Pacific that was collected for the first time in the Caribbean in the 1980s also has cloning larvae," Collin said.


Parents unknown—Mysterious larvae found in Panama's two oceans
More information: Rachel Collin et al, World Travelers: DNA Barcoding Unmasks the Origin of Cloning Asteroid Larvae from the Caribbean, The Biological Bulletin (2020). DOI: 10.1086/710796
Provided by Smithsonian Tropical Research Institute

Mathematician refines model of predator-prey relations in the wild

by RUDN University
The traditional mathematical model of predator-prey relations in the wild does not take into account indirect nonlocal interactions. However, according to a mathematician from RUDN University, they affect the dynamics of predators and prey in a system, and the nature of this effect is sensitive to the initial conditions. Credit: RUDN University

The traditional mathematical model of predator-prey relations in the wild does not take into account indirect nonlocal interactions. However, according to a mathematician from RUDN University, they affect the dynamics of predators and prey in a system, and the nature of this effect is sensitive to the initial conditions. An article about his work was published in the Communications in Nonlinear Science and Numerical Simulation journal.


Ecologists use mathematical models of ecosystems to understand their structure and predict their development. Predator-prey is one of the basic models of this kind. With its help scientists can for instance calculate changes in the numbers of carnivores and herbivores depending on numerous conditions: the breeding of the latter, starvation of the former, amounts of prey eaten by predators, migrations, and so on. However, this model only takes into account local interactions, i.e. direct interactions between predators and prey in each given spatial location, while actual ecosystems also include nonlocal ones. A mathematician from RUDN University working together with his colleagues from the UK and India enhanced the standard predator-prey model taking these less obvious factors into account. Using his work, ecologists will be able to better understand developments in natural systems.

One example of natural nonlocal interactions is arid regions. To grow there, plants need to have a vast root system to collect moisture from large territories, not just from the vicinity of their location. Mathematically, this nonlocality is expressed as an integral that sums up the effect of the whole system at each given point. The competition for food among herbivores is also nonlocal, so a model has to take into account the integral amount of food in a system, not at each particular place.

"Nonlocal properties of movement are of interest for researchers; however, the nonlocal origin of this dynamics is often discarded. Still, there are a lot of natural systems with nonlocal interactions. One of the best examples may be the vegetation-water system, especially in semi-arid regions. There, nonlocality is a direct result of extensive root networks. We have confirmed that the nonlocality of intraspecific interactions can be the cause of different system dynamics in the predator-prey model," said Prof. Sergey Petrovskii from RUDN University.

The team tested their concept using computer modeling and found out that even if a system initially has equal numbers of carnivores and herbivores, after some time their quantities start to grow differently at different points due to nonlocal interactions. As a result, the total quantity of the system becomes dominated either by predators or prey, and different spatial patterns are formed. Another feature of a nonlocal system is bistability, i.e. possible coexistence of two patterns. This is an important attribute of nonlocality. It is the initial conditions that determine which pattern eventually succeeds.


Predator and prey in cyber stasis
More information: Swadesh Pal et al, Spatiotemporal pattern formation in 2D prey-predator system with nonlocal intraspecific competition, Communications in Nonlinear Science and Numerical Simulation (2020). DOI: 10.1016/j.cnsns.2020.105478
Provided by RUDN University

Beak bone reveals pterosaur like no other

by University of Portsmouth

An artist's impression of Leptostomia begaaensis

 Credit: Megan Jacobs, University of Portsmouth

A new species of small pterosaur—similar in size to a turkey—has been discovered, which is unlike any other pterosaur seen before due to its long slender toothless beak.

The fossilised piece of beak was a surprising find and was initially assumed to be part of the fin spine of a fish, but a team of palaeontologists from the universities of Portsmouth and Bath spotted the unusual texture of the bone—seen only in pterosaurs—and realised it was a piece of beak.

Professor David Martill of the University of Portsmouth, who co-authored the study, said: "We've never seen anything like this little pterosaur before. The bizarre shape of the beak was so unique, at first the fossils weren't recognised as a pterosaur."

Careful searching of the late Cretaceous Kem Kem strata of Morocco, where this particular bone was found, revealed additional fossils of the animal, which led to the team concluding it was a new species with a long, skinny beak, like that of a Kiwi.

Lead author of the project, University of Portsmouth Ph.D. student Roy Smith, said: "Just imagine how delighted I was, while on field work in Morocco, to discover the lower jaw to match the upper jaw found by Dr. Longrich of this utterly unique fossil animal."

The new species, Leptostomia begaaensis, used its beak to probe dirt and mud for hidden prey, hunting like present-day sandpipers or kiwis to find worms, crustaceans, and perhaps even small hard-shelled clams.

Pterosaurs are the less well-known cousins of dinosaurs. Over 100 species of these winged-reptiles are known, some as large as a fighter jet and others as small as a sparrow.

Professor Martill said: "The diets and hunting strategies of pterosaurs were diverse—they likely ate meat, fish and insects. The giant 500-pound pterosaurs probably ate whatever they wanted.

"Some species hunted food on the wing, others stalked their prey on the ground. Now, the fragments of this remarkable little pterosaur show a lifestyle previously unknown for pterosaurs."

The scientists used a computerised tomography (CT) scan to reveal an incredible network of internal canals for nerves that helped detect the prey underground.


Dr. Nick Longrich, from the Milner Centre for Evolution at the University of Bath, said: "Leptostomia may actually have been a fairly common pterosaur, but it's so strange—people have probably been finding bits of this beast for years, but we didn't know what they were until now."

Long, slender beaks evolved in many modern birds. Those most similar to Leptostomia are probing birds—like sandpipers, kiwis, curlews, ibises and hoopoes. Some of these birds forage in earth for earthworms while others forage along beaches and tidal flats, feeding on bristle worms, fiddler crabs, and small clams.

Leptostomia could probably have done either, but its presence in the Cretaceous age Kem Kem strata of Africa—representing a rich ecosystem of rivers and estuaries—suggests it was drawn there to feed on aquatic prey.

"You might think of the pterosaur as imitating the strategy used successfully by modern birds, but it was the pterosaur that got there first," said Dr. Longrich. "Birds just reinvented what pterosaurs had already done tens of millions of years earlier."

Dr. Longrich suggests the new species shows how, more than a century after pterosaurs were first discovered, there's still so much to learn about them. He said: "We're underestimating pterosaur diversity because the fossil record gives us a biased picture.

"Pterosaur fossils typically preserve in watery settings—seas, lakes, and lagoons—because water carries sediments to bury bones. Pterosaurs flying over water to hunt for fish tend to fall in and die, so they're common as fossils. Pterosaurs hunting along the margins of the water will preserve more rarely, and many from inland habitats may never preserve as fossils at all.

"There's a similar pattern in birds. If all we had of birds was their fossils, we'd probably think that birds were mostly aquatic things like penguins, puffins, ducks and albatrosses. Even though they're a minority of the species, their fossil record is a lot better than for land birds like hummingbirds, hawks, and ostriches."

Over time, more and more species of pterosaurs with diverse lifestyles have been discovered. That trend, the new pterosaur suggests, is likely to continue.


Naked prehistoric monsters: Evidence that prehistoric flying reptiles probably had feathers refuted
More information: Roy E. Smith et al, A long-billed, possible probe-feeding pterosaur (Pterodactyloidea: ?Azhdarchoidea) from the mid-Cretaceous of Morocco, North Africa, Cretaceous Research (2020). 

DOI: 10.1016/j.cretres.2020.104643
Journal information: Cretaceous Research
Provided by University of Portsmouth

Research finds biodegradable alternatives are no better for the environment

by Anglia Ruskin University

Close up of cellulose glitter used in the experiment Credit: Dr Dannielle Green, Anglia Ruskin University (ARU)

New research indicates that glitter could be causing ecological damage to our rivers and lakes.

The study, led by Dr. Dannielle Green of Anglia Ruskin University (ARU) and published in the Journal of Hazardous Materials, is the first to examine the impact of glitter on freshwater habitats.

The research found that after 36 days, the presence of glitter halved the root length of common duckweed (Lemna minor), while levels of chlorophyll in the water were three times lower than in control conditions, indicating reduced levels of phytoplankton, or microalgae.

Glitter is used in a variety of decorative ways, including on clothing, in arts and crafts, and in cosmetics and body paint. Traditional glitter is a form of microplastic consisting of a plastic core made of polyester PET film, which is coated with aluminium and then covered with another thin plastic layer.

Along with other forms of single use microplastics, such as microbeads, there have been efforts to phase out PET glitter with the introduction of more biodegradable alternatives.

One version has a core of modified regenerated cellulose (MRC), sourced mainly from eucalyptus trees, but this is still coated with aluminium for reflectivity and then topped with a thin plastic layer. Another form is mica glitter, which is increasingly used in cosmetics.

Close up of PET glitter used in the experiment Credit: Dr Dannielle Green, Anglia Ruskin University (ARU)

However, this new study found that the effects of MRC and mica glitters on root length and chlorophyll levels were almost identical to those of traditional glitter.

The only significant difference was a two-fold increase in the abundance of New Zealand mud snails (Potamopyrgus antipodarum) in water containing the biodegradable MRC glitter. These snails, commonly found in polluted waters, are an invasive species in the UK and an increase in numbers has the potential to disrupt ecosystems, as they can outcompete native species.

Dr. Dannielle Green, Senior Lecturer in Biology at Anglia Ruskin University (ARU), said: "Many of the microplastics found in our rivers and oceans have taken years to form, as larger pieces of plastic are broken down over time, However, glitter is a ready-made microplastic that is commonly found in our homes and, particularly through cosmetics, is washed off in our sinks and into the water system.

"Our study is the first to look at the effects of glitter in a freshwater environment and we found that both conventional and alternative glitters can have a serious ecological impact on aquatic ecosystems within a short period of time.

Close up of mica glitter used in the experiment Credit: Dr Dannielle Green, Anglia Ruskin University (ARU)

"All types, including so-called biodegradable glitter, have a negative effect on important primary producers which are the base of the food web, while glitter with a biodegradable cellulose core has an additional impact of encouraging the growth of an invasive species.

"We believe these effects could be caused by leachate from the glitters, possibly from their plastic coating or other materials involved in their production, and our future research will investigate this in greater detail."

Sustainable shopping—take the 'litter' out of glitter
More information: Dannielle Senga Green et al, All that glitters is litter? Ecological impacts of conventional versus biodegradable glitter in a freshwater habitat, Journal of Hazardous Materials (2020). DOI: 10.1016/j.jhazmat.2020.124070
Journal information: Journal of Hazardous Materials

Provided by Anglia Ruskin University

Magnitude comparison distinguishes small earthquakes from explosions in US West

by Seismological Society of America

Credit: Unsplash/CC0 Public Domain

By comparing two magnitude measurements for seismic events recorded locally, researchers can tell whether the event was a small earthquake or a single-fire buried chemical explosion.

The findings, published in the Bulletin of the Seismological Society of America, give seismologists one more tool to monitor nuclear explosions, particularly low-yield explosions that are detected using seismic stations that are 150 kilometers (about 93 miles) or less from the explosion site.

Seismologists use a variety of methods to distinguish earthquakes from explosions, such as analyzing the ratio of P waves (which compress rock in the same direction as a wave's movement) to S waves (which move rock perpendicular to the wave direction). However, methods like the P/S-wave ratio do not work as well for events of magnitude 3 or smaller, making it essential to develop other discrimination techniques, said University of Utah seismologist Keith Koper. Scientists have debated, for instance, whether a small seismic event that took place on 12 May 2010 in North Korea was a natural earthquake or an earthquake induced by a low-yield nuclear explosion.

The new study looks at the difference between local magnitude (ML) and coda duration magnitude (MC) measurements. Local magnitude, sometimes referred to as Richter magnitude, estimates magnitude based on the maximum amplitude of seismic waves detected. Coda duration magnitude is based on the duration of a seismic wave train and the resulting length of the seismogram it produces.

Koper and his students stumbled across the potential usefulness of this comparison in one of his graduate seminars about four years ago, as the students practiced programming and comparing different types of magnitudes. "It turned out that when you looked at these magnitude differences, there was a pattern," he said. "All these earthquakes in Utah that are associated with coal mining have a bigger coda magnitude, with seismograms longer than normal."

Compared to naturally occurring earthquakes, seismic events caused by human activity tend to have a larger MC than ML, the researchers concluded in a 2016 paper. Very shallow seismic events have a larger MC than deeper buried events, they found, while noting that most human activities that would induce earthquakes take place at shallow depths in the crust, compared to the deeper origins of natural earthquakes.

The findings suggested that ML-MC difference could be useful in detecting nuclear explosions at a local level, but the multiple detonations in a coal mining operation, scattered in space and time, produce a different seismic signature than the compact single shot of a nuclear explosion.

To further test the discrimination method, the researchers searched for "explosions that were better proxies, compact, and not your typical industrial explosions," Koper said.

In the BSSA study, Koper and colleagues applied the ML-MC difference to three experiments in the U.S. West that recorded data on local networks from buried single-fire explosions as well as natural earthquakes: the 2010 Bighorn Arch Seismic Experiment (BASE) in northern Wyoming, the imaging Magma Under St. Helens (iMUSH) experiment in Washington State from 2014 to 2016, and the Phase I explosions of the Source Physics Experiment (SPE) in Nevada from 2011 to 2016.

The method was able to successfully separate explosions from natural earthquakes in the data from all three sites, the researchers found, confirming that it would be potentially useful for identifying small underground nuclear explosions in places that are only covered by a local seismic network.

Beyond explosion seismology, the method might also help identify and analyze other earthquakes that have shallow sources, including some earthquakes induced by human activities such as oil and gas recovery, Koper said.


North American seismic networks can contribute to nuclear security
More information: Keith D. Koper et al. Discrimination of Small Earthquakes and Buried Single‐Fired Chemical Explosions at Local Distances (⁠<150  km⁠) in the Western United States from Comparison of Local Magnitude (⁠ML⁠) and Coda Duration Magnitude (⁠MC⁠). Bulletin of the Seismological Society of America (2020) DOI: 10.1785/0120200188
Journal information: Bulletin of the Seismological Society of America
Provided by Seismological Society of America

People can do more than use less plastic to help save the Great Barrier Reef (GBR)

by Queensland University of Technology

QUT researchers say a survey they conducted found most Australians don't make a connection between climate change and the health of the Great Barrier Reef. Credit: QUT

Many Australians do not know what they can individually do to make a difference to the health of the World Heritage-listed Great Barrier Reef (GBR), according to a survey led by QUT researchers.

The researchers found most Australians are not making a connection between climate change and reef health and say there is more individuals could do on this front, both in the home and to influence government policies.

Senior Research Fellow Dr. Angela Dean conducted the online survey of 4,285 Australians with Professor Kerrie Wilson, Director of QUT's Institute for Future Environments, and Dr. Robyn Gulliver from the University of Queensland.

The resulting paper, "Taking action for the Reef?"—Australians do not connect Reef conservation with individual climate-related actions, has been published in Conservation Letters: a journal of the Society for Conservation Biology.

"While there are many threats to reef health, including poor water quality stemming from land-based runoff, cyclones and crown-of-thorns starfish, climate change represents the greatest threat to our Great Barrier Reef," said Dr. Dean.

"Record-breaking marine heatwaves over the past 10 years have seen an increasing frequency and severity of mass coral bleaching events.

"Yet while many Australians express appreciation and concern for the GBR, they don't necessarily know how to take the next steps to help the Reef."

The research team asked survey participants the question "what types of actions could people like you do that would be helpful for the GBR?"

"Just 4 per cent mentioned a climate action and 12.3 per cent wanted to help but couldn't think of anything they could do on a personal level," said Professor Wilson

"Only one in 25 respondents identified at least one specific action that related to climate change. Almost one third listed donating money and the most common group of responses related to pollution, especially plastics."

Professor Wilson said the vast majority of those surveyed referenced reducing their plastic consumption over using less energy in the home.

"Only a handful of people considered that they could make a difference by doing things like driving less, reducing their use of air-conditioning and sourcing electricity from renewable retailers," she said.

"As for what we call public-sphere actions, many more respondents suggested policies such as banning sunscreens or stopping commercial fishing, rather than any climate-related civic action such as lobbying governments or donating to charities working on reducing emissions."

Dr. Dean added because everyone can support action on climate change, everyone in Australia can help the Reef, no matter where they live.

"Some people might choose to focus on actions at home, reducing electricity use or changing to renewable energy sources," Dr. Dean said.

"But perhaps more important is sharing our support for protecting the Reef and encouraging Governments step up to show leadership and action on climate change."


Survey shows Aussies' love and concern for Great Barrier Reef
More information: Angela J. Dean et al, "Taking action for the Reef?"-Australians do not connect Reef conservation with individual climate-related actions, Conservation Letters (2020). DOI: 10.1111/conl.12765
Journal information: Conservation Letters
Provided by Queensland University of Technology

Unique view into the 'new Arctic': International MOSAiC expedition successfully completed

by Tilo Arnhold, Leibniz Institute for Tropospheric Research (TROPOS)

Polarstern during the polar night in the Arctic.

 Credit: Hannes Griesche, TROPOS

Bremerhaven/Leipzig. With the return of the Polarstern, the largest Arctic expedition of all times has come to a successful end. For more than a year, the German research icebreaker traveled in 5 cruise legs with more than 400 people from 20 countries to investigate the epicenter of climate change more precisely than ever before. At the end of the expedition, which cost around 140 million euros, the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), came to a positive conclusion: despite all the unforeseeable difficulties, it had succeeded in advancing knowledge about the Earth's climate system and its changes by a decisive step.


From Leipzig's point of view, the complex project was also successful: all 7 participants from the Leibniz Institute for Tropospheric Research (TROPOS) and the Leipzig University are back in good health and with valuable climate data. Two measurement programs that are central to research into the Arctic atmosphere were able to be carried out in full despite weather extremes and corona: A multi-wavelength lidar scanned the air layers above Polarstern during the entire expedition. In 369 days, 640 million laser pulses went into the sky and 112 gigabytes of data were collected. In July, the MOSAiC atmosphere team was able to measure the lowest air layer above the melting ice floe with a captive balloon. Within a tight time window, 33 balloon ascents were achieved, during which a total of 31,725 meters of rope were unwound and rewound. The balloon measurements by TROPOS and Leipzig University are particularly important for understanding the polar atmosphere during the melting phase, because the measurements originally planned in parallel with aircraft from Spitsbergen had to be postponed until autumn due to the corona pandemic.

"We are pleased that the ambitious plans have essentially been realized despite all the difficulties. A highlight are definitely the insights into the troposphere at the North Pole during the winter with our lidar. Nobody has ever been able to observe it so far north during the polar night off MOSAiC," says Prof. Andreas Macke, Director of TROPOS. The evaluation of the data is still in full swing, but there are indications that the same applies to the atmosphere as to the ice on the ground: "There are many indications that the atmosphere of the Arctic has already changed significantly. We have seen more smoke than expected. The huge forest fires are apparently affecting the polar regions. Even these once pristine areas seem to have reached the "Pyrocene." However, it will take months before concrete results are available, during which the data will have to be examined, analyzed and discussed before they can finally be published. "The fact that we have measured both the atmosphere and the energy balance on the ground over a complete Arctic year will contribute greatly to our understanding of Arctic warming," adds Macke.
  

The captive balloon of TROPOS and Leipzig University in action on the ice floe during arctic summer. Credit: Lianna Nixon, University of Colorado / AWI

At the moment, the joy that people and technology have survived the strains well outweighs. Also at Dr. Ronny Engelmann, scientist and laser expert from TROPOS, who is responsible for the remote sensing measurements within the OCEANET project on Polarstern: "It was fascinating to experience the Arctic in winter and to be allowed to be in a region where only a few people have been before at this time of year. As a scientist, I am glad that, thanks to good care by my colleagues, our equipment has been able to last for a year and has also survived the extreme cold of the polar night with temperatures down to -40 degrees Celsius without any failures. The experiences of the last ten years, during which our OCEANET container has been on board of Polarstern, have been a great help. Without stable technology, we would never have known what dust layers had moved across the Arctic," physicist Engelmann looks back. The lidar was in operation from 28 September 2019 to 02 October 2020 without any significant failures. This was ensured by Dr. Ronny Engelmann, Hannes Griesche, Martin Radenz, Julian Hofer and Dr. Dietrich Althausen, some of whom spent up to four months on the five sections of the cruise. Even though the remote sensing instruments run mostly automatically, they need regular maintenance: the flash lamps that emit the laser pulses had to be changed five times, for example, or 60 liters of liquid nitrogen had to be replaced each time the microwave radiometer was calibrated. Together with other instruments such as radiation meters, cloud camera, rain gauge and photometer on the OCEANET measuring container from TROPOS, a total of over one and a half terabytes of data were collected and around 60,000 kWh of electricity was consumed.


While the remote sensing instruments on the foredeck of Polarstern could practically run the entire expedition, the teams on the ice had only a short time window each, which had to be used as effectively as possible. The balloon team from TROPOS and Leipzig University was able to work on the ice for a total of 37 days. Thanks to support from other teams, 33 balloon ascents were achieved, in which the BELUGA tethered balloon, which was the size of a bus, could measure aerosol particles, radiation and meteorological parameters up to a height of 1500 meters above the ice. To fill the balloon several times, 474 cubic meters of helium were consumed and holes up to 6 meters deep had to be drilled into the thawing ice for the ice anchors. "Our time on the ice was short but intense. The many melt ponds and frequent polar bear visits demanded a lot of improvisation. Because of the support from the whole MOSAiC team we were able to master difficult situations. This made our balloon measurements a big team effort from a great team that I will remember for a long time to come," said Christian Pilz of TROPOS. The vertical profiles that Pilz recorded together with the radiation measurements of his colleague Michael Lonardi from Leipzig University will provide important insights into the lower atmosphere of the summer Arctic. For example, the team was able to register temperatures of 14 degrees Celsius at an altitude of 300 meters, although the temperature on the ground was only just above freezing point. Without such on-site measurements, it would not be possible to estimate the influence of the air layers on the ground on thawing sea ice.

Originally it was planned to study the near-ground atmosphere above the MOSAiC ice floe by tethered balloon and the higher layers by airplane in early summer. However, due to the corona pandemic, flights via Spitsbergen were not possible at that time. Supply and personnel exchange had to be organized with research vessels from Germany and the aircraft campaign had to be postponed until September. "The measurements with the Leipzig tethered balloon are therefore important in-situ aerosol measurements at MOSAiC in this layer of air, which is very important for the climate in the Arctic," emphasizes Andreas Macke from TROPOS, "As an atmospheric researcher, I am particularly pleased that the balloon experiment was successful for the second time after 2017 and provided very valuable data."
  

The captive balloon of TROPOS and Leipzig University in action on the ice floe during arctic summer. Credit: Christian Pilz, TROPOS

In September 2020, the German research aircraft Polar 5 and Polar 6 of the AWI were the first foreign aircraft to take off from the airport Longyearbyen for several measurement flights from Spitsbergen to the central Arctic to study the atmosphere in the context of MOSAiC since the corona lockdown: "With the extensive measurements on radiation and particles, we want to find out how clouds in the Arctic affect warming on the ground. In recent years, the Arctic has warmed up more than any other region on earth. The feedback mechanisms involved are very complex and not yet sufficiently understood. This knowledge is essential, however, if climate models are to be able to estimate how quickly the climate there will change, even for the region around the North Pole," explains Prof. Manfred Wendisch from the Leipzig University, who is also the spokesman for the Collaborative Research Centre "Arctic Climate Change" of the German Research Foundation (DFG). The network includes the universities in Bremen, Cologne and Leipzig as well as the AWI in Bremerhaven and the TROPOS in Leipzig. The aim of the research network is to observe the dramatic climate change in the Arctic using various methods in order to improve the reliability of models and enable more accurate predictions of further warming in the Arctic. The MOSAiC expedition will make a significant contribution to this and will be intensively evaluated by the alliance partners in the coming months.

"I'm very pleased with how the MOSAiC expedition progressed, and what a complete success it has been. Through the expedition, we can provide the climate data and observations that humanity so urgently needs in order to make fundamental and pressing political decisions on climate protection," said Prof Markus Rex, Expedition Leader and head of the MOSAiC project, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). "We've seen how the Arctic ice is dying. In the summer, even at the North Pole, it was characterized by extensive melting and erosion. If we don't make immediate and sweeping efforts to combat climate warming, we'll soon see ice-free Arctic summers, which will have incalculable repercussions for our own weather and climate. Though today the Central Arctic remains a fascinating, frozen landscape in winter, the ice is only half as thick as it was 40 years ago, and the winter temperatures we encountered were nearly always ten degrees warmer than what Fridtjof Nansen experienced on his ground-breaking Arctic expedition over 125 years ago."

On 20 September 2019 Polarstern departed from the Norwegian port of Tromsø, bound for the Central Arctic, the epicenter of climate change. Once there, the ship allowed itself to become trapped in the ice, and began a one-year-long drift across the North Pole, completely at the mercy of natural forces—the route and speed were solely determined by the ice drift, powered by wind and currents. Over the five cruise legs of the expedition, a total of 442 researchers, Polarstern crewmembers, young investigators, teachers and members of the press took part. Seven ships, several aircraft and more than 80 institutions from 20 countries were involved. The researchers, who hailed from 37 countries, had a common goal: to investigate complex interactions in the climate system between the atmosphere, ice and ocean, so as to better represent them in climate models. They also explored life in the Central Arctic for an entire year. Now they have returned home with a wealth of impressions from the rapidly transforming Arctic, and with an unparalleled treasure trove of data, which an entire generation of climate researchers will focus on analyzing.

From Leipzig's perspective, the next major measurement campaign in the Arctic will be the "HALO (AC)" mission with the German research aircraft HALO and Polar 6 in spring 2022. The tethered balloon BELUGA, on the other hand, will already return to the Arctic skies in late summer 2021—if pandemic conditions permit. This time, however, from solid ground in the research village Ny-Ålesund on Spitsbergen.


Explore further  The Arctic atmosphere: A gathering place for dust?
More information: Hannes J. Griesche et al, Application of the shipborne remote sensing supersite OCEANET for profiling of Arctic aerosols and clouds during Polarstern cruise PS106, Atmospheric Measurement Techniques (2020). DOI: 10.5194/amt-13-5335-2020
Provided by Leibniz Institute for Tropospheric Research (TROPOS)