Beaches can survive sea-level rises as long as they have space to move

UNIVERSITY OF PLYMOUTH

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IMAGE: SLAPTON SANDS IN DEVON (UK), WITH THE VILLAGE OF TORCROSS IN THE FOREGROUND, IS AN EXAMPLE OF WHERE THE BEACH HAS SPACE TO MOVE AND THEREFORE SURVIVE view more 

CREDIT: UNIVERSITY OF PLYMOUTH

An international team of coastal scientists has dismissed suggestions that half the world's beaches could become extinct over the course of the 21st century.

The claim was made by European researchers in a paper published in Nature Climate Change in March 2020 (Sandy coastlines under threat of erosion by Vousdoukas et al).

However, academics from the UK, France, South Africa, Australia, New Zealand and the USA have re-examined the data and methodology that underpinned the original study and say they strongly disagree with its conclusion.

They have now published a rebuttal to the article in the same journal, and concluded that with the global data and numerical methods available today it is impossible to make such global and wide-reaching predictions.

Critical to their disagreement with the original paper's conclusions is the fact that they say there is potential for beaches to migrate landwards as sea level rises and shorelines retreat.

The key notion behind that is that if beaches have space to move into under the influence of rising sea levels - referred to as accommodation space - they will retain their overall shape and form but in a more landward position.

The new research says that beaches backed by hard coastal cliffs and engineering structures, such as seawalls, are indeed likely to disappear in the future due to sea-level rise as these beaches are unable to migrate landward.

They will first experience 'coastal squeeze' resulting in a decrease in width, and will eventually drown.

However, beaches backed by low-lying coastal plains, shallow lagoons, salt marshes and dunes will migrate landward as a result of rising sea level. In these cases, the shoreline will retreat, but the beaches are still likely to remain, albeit a little raised in elevation and located landward, and will certainly not go 'extinct'.

The new paper says there is currently no information available globally on the number of beaches which fall into either category and, as such, it is impossible to quantify what proportion of the world's beaches will disappear between now and 2100.

Andrew Cooper, Professor of Coastal Studies at Ulster University and the new paper's lead author, said: "New methods are needed for predicting impacts of sea-level rise on the coast. This will require better datasets of coastal morphology and improved understanding of the mechanisms of shoreline response in given settings. As sea level rises, shoreline retreat must, and will, happen but beaches will survive. The biggest threat to the continued existence of beaches is coastal defence structures that limit their ability to migrate."

Co-author Professor Gerd Masselink, from the University of Plymouth's Coastal Processes Research Group, led a study earlier this year which found that island 'drowning' is not inevitable as sea levels rise.

He added: "Sea level is currently rising and will continue to rise at an increasing rate for many years to come. This will lead to more coastal erosion and it is crucial that we anticipate the future loss of land and take this into account in coastal management and planning to avoid putting more buildings and coastal infrastructure in harm's way. In the UK, Coastal Change Management Areas (CCMAs) are becoming increasingly important as a planning tool. CCMAs are areas that are likely to be affected by coastal change in the future and development in these areas should be avoided. This will then enable the coastline to respond naturally to sea-level rise, preventing coastal squeeze and loss of beaches."

Coastal structures such as seawalls prevent beaches from naturally adjusting to rising sea levels by migrating landward and in those settings, removal of the structures (managed realignment) or nature-based solutions (beach nourishment) may be the only methods to safeguard the future of these beaches.

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Yeast study yields insights into longstanding evolution debate

YALE UNIVERSITY

Research News

 

In the past two decades, researchers have shown that biological traits in both species and individual cells can be shaped by the environment and inherited even without gene mutations, an outcome that contradicts one of the classical interpretations of Darwinian theory.

But exactly how these epigenetic, or non-genetic, traits are inherited has been unclear.

Now, in a study published Oct. 27 in the journal Cell Reports, Yale scientists show how epigenetic mechanisms contribute in real time to the evolution of a gene network in yeast. Specifically, through multiple generations yeast cells were found to pass on changes in gene activity induced by researchers.

The finding helps shed light on a longstanding question in evolutionary biology; scientists have long debated whether organisms can pass on traits acquired during a lifetime.

"Do genetic mutations have to be the sole facilitator of gene network evolution or can epigenetic mechanisms also lead to stable and heritable gene expression states maintained generation after generation?" asked Yale's Murat Acar, associate professor of molecular, cellular & developmental biology, a faculty member at the Yale Systems Biology Institute, and senior author of the paper.

During much of the last half of the 20th century, biology students were taught that mutations of genes that helped species adapt to the environment were passed on through generations, eventually leading to tremendous diversity of life. However, this theory had a problem: advantageous mutations are rare, and it would take many generations for physiological changes caused by the mutation to take root in a population of any given species.

Scientists in the last century have found that certain regions of DNA do not code for genes but regulate gene activity in the face of environmental change. The concept of passing on stable gene expression states to offspring resurrected the once widely discredited theories of 18th century French scientist Jean-Baptiste Lamarck, who first proposed inheritance of traits acquired during a lifetime.

For the new study, Acar lab graduate students and co-first authors Xinyue Luo and Ruijie Song wanted to investigate the role of epigenetic inheritance in the evolution of gene network activity in individual yeast cells, which reproduce asexually about every 100 minutes. As their experimental model, they investigated a gene network known as the galactose utilization network, which regulates use of the sugar-like molecule galactose, in the yeast. Through daily cell-sorting, they segregated the cells that had lowest levels of gene expression in the population and grew these cells in the same environment over a period of seven days.

Ultimately, they found expression level reductions persisted for several days and multiple generations of reproduction after the 7-day segregation period. Genetic causes alone could not explain the expression reduction; inheritance of epigenetic factors contributed to the observed change, the Yale team found.

Acar said the findings show a clear Lamarckian epigenetic contribution to gene network evolution and the classic Darwinian interpretation of evolution alone cannot explain our observations. "The findings support the idea that both genetic and epigenetic mechanisms need to be combined in a 'grand unified theory of evolution,'" he said.

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Other authors include Mark Hochstrasser, the Eugene Higgins Professor of Molecular Biophysics and Biochemistry and professor of molecular, cellular, and developmental biology, and postdoctoral associates David Moreno and Hong-Yeoul Ryu.

 

Photovoltaics industry can help meet Paris agreement targets

Model predicts efficiency of solar photovoltaic cells, costs to manufacture them during a transition to 100% renewable energy within the next few decades

AMERICAN INSTITUTE OF PHYSICS

Research News

 

IMAGE: A FAST GROWTH SCENARIO OF THE PHOTOVOLTAICS INDUSTRY REQUIRES INCREASING ANNUAL PRODUCTION VOLUME 25% PER YEAR, WHICH WOULD BRING THE ANNUAL PRODUCTION TO A STABILIZED LEVEL OF ABOUT 3 GIGAWATTS... view more 

CREDIT: PIERRE VERLINDEN

WASHINGTON, October 27, 2020 -- To meet the Paris Agreement's daunting goal of preventing Earth's average temperature from rising more than 2 degrees Celsius (3.6 degrees Fahrenheit) above its level in preindustrial times, one of the best options for the energy economy will involve a shift to 100% renewable energy using solar energy and several other clean energy sources.

While no one knows exactly how an increase above 2 degrees Celsius would impact the planet, extraordinary climatic events would likely make many parts of the world uninhabitable with significant desertification, ocean acidification, and rise of seawater level, as well as floods, wildfires, hurricanes, and tornadoes.

In the Journal of Renewable and Sustainable Energy, from AIP Publishing, Pierre J. Verlinden, founder of AMROCK Pty. Ltd. in Australia, describes a model developed to predict what is necessary for the solar industry to meet Paris Agreement targets.

"Our planet is on the path of an average temperature increase of 4 degrees Celsius before the end of this century, with respect to the average Earth temperature before the industrial age, and the result will be catastrophic," Verlinden said.

Climate experts predict only 800 gigatons of carbon dioxide can be emitted before crossing the 2 degrees Celsius line. This means that at the current global emission of 36 gigatons per year, there is a 35-year window to reduce our emissions to zero.

One way to achieve this goal is to change the way energy is produced and consumed.

"Our vision is solar photovoltaics can play a central role in a transformed sustainable energy economy with 100% decarbonized electricity generation to power directly or indirectly -- through the production of green hydrogen or other synthetic fuels -- all energy sectors and industrial processes," said Verlinden.

The world will require, in addition to other renewable energy sources like wind and hydro, about 70 to 80 terawatts of cumulative capacity from solar photovoltaic systems. This represents more than 100 times the world's current solar photovoltaic installed capacity.

"Within the next 10 years, the industry needs to increase its production rate by a factor of about 30," he said.

A model developed by Verlinden and colleagues to predict the efficiency of solar cells and their cost to manufacture during the next few decades shows there "is no fundamental barrier to achieving this goal," he said.

The financial requirement to grow the production rate (capital expenditures to build new production lines) is decreasing at a rate of 18% per year, driven by productivity improvements and a combination of higher-throughput per tool, larger wafers, and improved cell efficiency.

"In terms of material sustainability, the only major issue is the use of silver for metallization of silicon solar cells," said Verlinden. "We need to reduce the use of silver in silicon solar cells from about 29 tons per gigawatt to less than 5 tons per gigawatt."

He cautions that while the objective of a cumulative installation of 70 or 80 terawatts by 2055 is achievable with a simple annual growth of the production rate of about 15% per year, pursuing this goal will result in a solar photovoltaic industry much larger than necessary. This could lead to a significant downturn when the objective of 80 terawatts is reached.

"This negative impact can be avoided if we right now accelerate the growth during the next 10 years and then stabilize the global production to 3 to 4 terawatts per year," Verlinden said.

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The article, "Future challenges for photovoltaic manufacturing at the terawatt level," is authored by Pierre J. Verlinden. It will appear in the Journal of Renewable and Sustainable Energy on October 27, 2020 (DOI: 10.1063/5.0020380). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0020380.

ABOUT THE JOURNAL

Journal of Renewable and Sustainable Energy is an interdisciplinary journal that publishes across all areas of renewable and sustainable energy relevant to the physical science and engineering communities. Topics covered include solar, wind, biofuels and more, as well as renewable energy integration, energy meteorology and climatology, and renewable resourcing and forecasting. See https://aip.scitation.org/journal/rse.

 

Stay focused: Algae-inspired polymers light the way for enhanced night vision

Researchers from the University of Tsukuba synthesize an elastic polymer from low-cost, sustainable materials, that can be used it to fabricate lenses that help keep infrared cameras focused in the dark

UNIVERSITY OF TSUKUBA

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CREDIT: UNIVERSITY OF TSUKUBA

Tsukuba, Japan - In a study recently published in ACS Applied Polymer Materials, researchers from the University of Tsukaba synthesized an infrared-transmitting polymer--based on low-cost, widely available materials--that retains its shape after stretching. The properties of this polymer are highly applicable to the preparation of cheaper night-vision lenses that retain focus while imaging at variable distances.

Cameras that function in the dark are common in many fields, including the military, security, firefighting, and wildlife tracking. However, infrared night-vision lenses are typically expensive, and the camera images tend to appear flat. Consequently, there is a need for lenses based on commonly available, cheap materials that are useful for more realistic vision in three dimensions.

The researchers' polymer is based on sulfur and compounds derived from algae and plants. The polymer is easy to prepare using a chemical process called inverse vulcanization: simply mix the constituent compounds together and stir while heating. As a first step, the researchers designed a polymer that is elastic--that is, reverts to its original shape--after being repeatedly restretched by 20%.

"Inverse vulcanization is an ideal synthetic approach for our polymers," explains lead author Professor Junpei Kuwabara. "Squalene and other long unsaturated hydrocarbons help optimize the cross-linking structure and give the polymers a desirable elasticity."

Next, the researchers needed to determine whether lenses constructed from their polymers are at least partially transparent to infrared light, for nighttime imaging. Lens construction was easy: simply pour the polymer into a lens-shaped silicone mold and heat for a few hours. Even a 3.3-millimeter-thick lens transmitted 10% of incoming infrared light.

"The lenses have two wavelength ranges that are infrared-transparent," says senior author Professor Takaki Kanbara. "No lens is completely transparent; 10% transmission is an excellent value for these materials."

Furthermore, the researchers confirmed that the polymer has variable-focus properties. By projecting an image through the lens, and monitoring the resulting image that came through while elongating the lens, much of the transmitted image remained in focus.

"The lens retained 54% of the focus variation, which is sufficient for practical uses," explains Dr. Takashi Fukuda, senior researcher, National Institute of Advanced Industrial Science and Technology (AIST). "The lens also retained its full initial focus after contracting back to its original shape."

The fabrication of conventional infrared night-vision lenses, in a way that allows users to easily change focus from one position to another, is typically difficult. Without a variable-focus capability, details that are pertinent to criminal or research investigations, for example, may be lost. The researchers of this study are overcoming current lens design limitations by using cheap, sustainable materials, and fabrication procecures that any researcher can carry out in their laboratory. Development of new materials in this area may benefit a range of sectors including emergency personnel and environmental researchers

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The article, "Algae-inspired, sulfur-based polymer with infrared transmission and elastic function," was published in ACS Applied Polymer Materials at DOI: 10.1021/acsapm.0c00924.

 

Endangered trees in Guam contribute to ecosystem diversity and health

UNIVERSITY OF GUAM

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IMAGE: ROOT NODULES FROM GUAM'S SERIANTHES NELSONII LEGUME TREE WITHIN WHICH BACTERIA CONVERT ATMOSPHERIC NITROGEN INTO A FIXED FORM THAT THE TREE CAN EXPLOIT. view more 

CREDIT: UNIVERSITY OF GUAM

Research at the University of Guam has shown that the decomposition of leaf litter from three threatened tree species releases nitrogen and carbon into the soil for use by other plants. The results illuminate the importance of biodiversity and the role certain organisms play in extracting nitrogen and carbon from the atmosphere and sequestering these elements in the biosphere. The findings were published in the September issue of the MDPI journal Nitrogen (doi:10.3390/nitrogen1020010).

A critically important nitrogen source

Carbon and nitrogen are abundant in the atmosphere, but the atmospheric forms are not directly used by plants. Green plants possess the ability to fix the atmospheric carbon through the process of photosynthesis, and this occurs without the aid of symbiotic microorganisms. Other plants have nitrogen-fixing microorganisms inside their roots, which allows them to directly benefit from atmospheric nitrogen.

Nitrogen is required in great quantities to sustain plant health, but most plants absorb the essential nitrogen from the soil. The source of this soil nitrogen is largely through the death and decay of leaves and roots of plants that form symbioses with nitrogen-fixing microorganisms.

"This means in a forest community, the trees that possess this specialized symbiosis are critically important as a nitrogen source for the other members of the forest," said Dr. Adrian Ares, associate director of the Western Pacific Tropical Research Center, where the research was conducted.

The model trees studied in the Guam research included the cycad species Cycas micronesica, the legume species Intsia bijuga, and the legume species Serianthes nelsonii.

The symbiosis between legume plants and the bacteria that grow inside root nodules has been heavily studied for decades, as many of the world's food crops are legumes and their contributions to the protein needs of humans are dependent on the nitrogen from their root symbionts. The symbiosis between cycad plants and the nitrogen-fixing cyanobacteria that grow inside specialized root structures, however, has been less studied.

"A greater understanding of the cycad-cyanobacteria symbiosis is of critical importance to understanding the biochemistry of cycad plants," said Benjamin Deloso, a cycad specialist at the University of Guam.

Rate of leaf decomposition

The research approach invoked the global plant research theme called the leaf economics spectrum. The Serianthes nelsonii leaflets are small and thin and do not require many resources for construction. Contrarily, the Cycas micronesica leaflets are large and thick and require copious resources for construction. Resources needed to build the Intsia bijuga leaflets fall in between the other two species.

"The principles that govern the leaf economics spectrum predicted that the speed of release of carbon and nitrogen from the dead leaf material would be rapid for Serianthes nelsonii and slow for Cycas micronesica," Deloso said.

The predictions were verified by the study. About 80% of the carbon and nitrogen pool was released from the Serianthes nelsonii litter in less than three months, and complete decomposition occurred in less than one year. In contrast, the release of carbon and nitrogen from Cycas micronesica litter was gradual and 25% to 30% of the initial carbon and nitrogen were still locked in the remaining litter after a full year of decomposition. The Intsia bijuga leaf litter decomposition rates were intermediate.

Knowledge for conservation decisions

One primary outcome from the research was the verification that these tree species modulate localized soil processes in a highly contrasting way, and these contrasts increase spatial heterogeneity in a manner that improves ecosystem health.

"Two of these tree species are endangered, and this new knowledge about the services that they provide to Guam's ecosystems is a critical part of developing improved conservation decisions," Ares said.

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Additional reading:

Marler, T.E. 2020. Perennial trees associating with nitrogen-fixing symbionts differ in leaf after-life nitrogen and carbon release. Nitrogen 1: 111-124; doi:10.3390/nitrogen1020010.

 

Cauliflower coral genome sequenced

KING ABDULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY (KAUST)

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IMAGE: KAUST RESEARCHERS COMPARED POPULATIONS OF CAULIFLOWER CORALS TO IDENTIFY SITES IN THE GENOME LINKED WITH ADAPTATIONS. view more 

CREDIT: © 2020 KAUST; HAGAN GEGNER

The sequencing of the genome of the cauliflower coral, Pocillopora verrucosa, by an international team, provides a resource that scientists can use to study how corals have adapted to different environmental conditions.

The cauliflower coral, also known as brush or lace coral, is one of the most popular corals in research because it is found throughout the Red Sea, the Indian Ocean and the Pacific Ocean. "Having the genome will help us understand the genetic basis underlying the species' adaptation to different environmental conditions," says Carol Buitrago-López, a Ph.D. student supervised by Christian R. Voolstra, "which might shine light on how corals could respond to global warming."

Buitrago-López was seeking a sequenced cauliflower coral genome for use in population genomics studies of corals throughout the Red Sea. The habitat gradient in the Red Sea waters means corals have adapted or acclimated to different conditions, such as variation in temperature, salinity and nutrients. After researchers compared populations to identify sites in the genome linked with these adaptations, the next step was to determine what those differences meant. A reference genome is invaluable in this process. "It's very helpful to know where specific genes are or to be able figure out which genes are under selection," says Buitrago-López.

The team's analysis predicted about 27,500 genes based on information from about 50,000 transcripts used for subsequent gene modeling, which is comparable to genomes from closely related corals. However, the cauliflower coral genome has a higher percentage of repetitive elements--in particular, more transposable elements--than closely related corals. This might be indicative of a radiation of the genus, which is consistent with the species' broad distribution in geography and depth.

The researchers also looked at the proportion of genes without introns, a typical signature of genes that were acquired through horizontal gene transfer. The proportion was similar to that in another Pocillopora coral and significantly greater than in a coral of a different genus. It is currently not known what these genes are for.

With the genome revealed, researchers can now investigate these and other patterns and work to understand the evolutionary history of these corals. Figuring out how they have adapted to conditions in the Red Sea may point toward ways to support corals to cope with the pressures of climate change. "With a sequenced genome, you're not working blindly," says Buitrago-López. "It will help to figure out where we should focus our attention."

 

Water consumption for trees is calculated in order to design precision irrigation systems

UNIVERSITY OF CÓRDOBA

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IMAGE: ALMOND TREE PLANTATION view more 

CREDIT: UNIVERSIDAD DE CÓRDOBA / PXHERE

In 1995, the severe drought that devastated Spain left some farms using irrigation agriculture without water supplies. Though it has not happened again since, climate change increases the chance of this threat. For farmers growing annual crops, an occurrence such as this one would mean losing a year's work but those who have groves of trees risk losing not only their year's production, but their long-term investment as well.

A research team from the University of Cordoba and the Institute for Sustainable Agriculture at the Spanish National Research Council in Cordoba has been working for years on several projects to improve water management and maximize the productivity of tree crops such as olives, almonds and citrus fruits. One of their lines of research is based on the fact that when there is a water shortage, trees transpire less, get warmer, and end up producing less.

In their latest research project, they studied how an indicator called Crop Water Stress Index (abbreviated to CWSI), based on detecting temperature increase in trees with water stress, is related to relative water consumption in an almond grove. Tree water consumption or transpiration is very difficult to measure whereas a tree's temperature is easily taken using remote sensors, similar to those used on a daily basis during the pandemic to detect people with fevers. In their latest work, this group experimentally demonstrated for the first time that there is a relationship between relative transpiration and the CWSI in almond trees. So, farmers can find out at any moment if the trees are consuming water at 80-90% of their capacity, meaning within optimal levels, or if they have high levels of stress and urgently need to be supplied with more water.

"This indicator, the CWSI, has the advantage that relative water consumption can be determined via remote sensing, using drones or manned planes and a map of the transpiration in different areas of a plantation can be obtained. In the future, satellites will most likely be used to do this work very precisely on big plantations", explains Elías Fereres, Professor Emeritus of the Agronomy Department at the University of Cordoba and a member of the research team, which is led by Victoria González Dugo from the Institute for Sustainable Agriculture at the Spanish National Research Council.

Therefore, these CWSI maps will allow for irrigating different areas of a farm in different ways in terms of the water level needed at each moment, thus maximizing production with the minimal necessary water resources or those available at the time. This research is within the framework of the technique known as precision irrigation, a new system that uses the most advanced technology to irrigate at an optimal level, supplying the exact amount of water to every part of the grove and circumventing losses. "The aim is to use water effectively and where it is most needed", points out Elías Fereres.

Though the research was performed on almond plantations, this research could be used on other tree crops such as olive trees, which are so important to the economy in Andalusia and on many occasions suffer from times of water shortages.

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A related project on which the group is also working is being led by Professor Francisco Villalobos from the University of Cordoba. It is called Project Olive-Miracle, which aims to develop a model to forecast how olive trees behave to climate change, which would provide more information in order to make decisions in the sector in the future.

V. Gonzalez-Dugo, L. Testi, F.J. Villalobos, A. López-Bernal, F. Orgaz, P.J. Zarco-Tejada y E. Fereres. "Empirical validation of the relationship between the crop water stress index and relative transpiration in almond trees". Agricultural and Forest Meteorology. DOI: https://doi.org/10.1016/j.agrformet.2020.108128

 

Can individual differences be detected in same-shaped pottery vessels by unknown craftsmen?

KOBE UNIVERSITY

Research News

IMAGE: CROSS RECURRENCE PLOTS OF HAND POSITION SEQUENCES A. TWO TRIALS BY THE SAME POTTER.?B. TWO TRIALS BY DIFFERENT POTTERS. THE LIGHT BLUE REGIONS SHOW WHEN SIMILAR HAND POSITIONS OCCURRED IN THE TWO... view more 

CREDIT: ©2020 GANDON ET AL.

An interdisciplinary research team has investigated whether there are quantitative differences that can be used to identify individual potters who make traditional, fixed-shape vessels that have been made in the same way for generations. Consequently, they discovered that there are clear variations between individuals in the formation process and hand movements used.

Members of the research team included Dr. Enora Gandon (Institute of Archaeology, University College London), Professor NONAKA Tetsushi (Graduate School of Human Development and Environment, Kobe University), and Professor Emeritus John A. Endler (Deakin University).

Up until now, the transmission of cultural traditions has been viewed in terms of 'imitation' and 'transmitted information'. However, the results quantitatively show that other factors beyond imitation, such as the individual's corresponding ability and exploratory learning process, play a role. In addition, it is hoped that these results will serve as a basis for determining whether unattributed archaeological artefacts were produced by one or multiple artisans.

These research results were published in the scientific journal 'PloS ONE' as two separate papers on September 22 and October 1 respectively.

Main Points

• There were quantitative differences distinct to individual potters, even when standard traditionally-shaped vessels were produced.
• There was greater diversity between potters during the formation process compared with the finished product.
• Multiple hand movement patterns that could be used to distinguish individual craftsmen were found.

Research Methodology and Findings

Humans pass down various skills to their communities and the next generation. One of these skills that has been transmitted since ancient times is pottery. This study investigated how the individuality of each craftsman stands out during the formation process of traditional pottery pieces, in particular the standardized, unsigned pottery produced for the mass-market.

First of all, the research team recorded video footage of potters making traditionally shaped pottery in the workshops of two different communities located in the Indian state of Uttar Pradesh (a Hindu community which uses a hand-operated stick-wheel, and a Muslim community which uses a foot-operated kick-wheel). The researchers performed an elliptical Fourier analysis on the recorded images in order to investigate the shape formation process during pottery throwing (Figure 1).

The results revealed that:

1. There were quantitatively distinguishable differences between the pottery produced by individual craftsmen, even among standard traditionally-shaped vessels produced for the consumer market.

2. There was greater variation between potters during the formation process than in the finished form.

Next, the researchers recorded video footage of traditional pottery shapes being made by craftsmen in a workshop in Bhaktapur, Nepal. The research team used this footage to analyze the hand movement patterns and transitions during the vessel formation processes, comparing them with those from the Indian communities.

Out of the 31 identified patterns of hand movements; similarities could be seen between different communities in approximately half of this number (cross-cultural), ten were particular to the Nepalese community (cultural), and five were identified as unique to the particular individual. The remaining movements were only observed once in one individual.

Cross Recurrence Quantification Analysis (CRQA) is a method used to quantify the dynamics of shared activity between two time series. CRQA was conducted on hand position sequences from different trials resulting in plots showing the temporal relationship between all possible combinations of hand positions in one trial with hand positions in another trial during the fashioning. These analyses revealed that there were hand position sequences that were unique to individual craftsmen (Figure 3).

The significance of this research

This research revealed that there is actually much variation in the formation process and the hand movements of the individual craftsmen, even when producing traditionally-shaped pottery in a manner that has been passed down for generations. From these results it can be surmised that each potter has been searching for their own distinct way of forming the shape of the vessel within the constraints of the tools used, such as the type of wheel, and differences in material.

Various theoretical models that have been proposed on the cultural transmission of handicrafts have viewed the inheritance of such skills as 'imitation' and 'transmitted information'. Conversely, this study provides quantitative evidence that traditional 'inherited' craftsmanship is more than mere imitation, shedding light on how individuals' ability is flexibly adopted from exploratory activities channeled by the social environment (e. g. of the pottery workshop) and the processes behind these factors. These aspects have been overlooked by existing theoretical models. The impact of these results will bring about the revision of existing theories that have reduced the transmission of traditional handicraft skills to 'imitation' and 'transmitted information'.

Furthermore, it is also hoped that this study's methodology and data could be used to determine whether unattributed archaeological artefacts were produced by an individual or several craftspeople.

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Photographs of the pottery produced and the study's conduction, as well as video recorded during the experiment, can be viewed on the Kobe University website.

Journal Information

Title: "Traditional craftspeople are not copycats: Potter idiosyncrasies in vessel morphogenesis" DOI: 10.1371/journal.pone.0239362

Authors: Enora Gandon*, Tetsushi Nonaka*, John A. Endler, Thelma Coyle, Reinoud J. Bootsma

* Contributing author

Journal: PLoS ONE

Title "Assessing the influence of culture on craft skills: A quantitative study with expert Nepalese potters" DOI: 10.1371/journal.pone.0239139

Authors Enora Gandon, Tetsushi Nonaka, Raphael Sonabend, John A. Endler

Journal: PLoS ONE

 

Butterfly color diversity due to female preferences

STOCKHOLM UNIVERSITY

Research News

 

IMAGE: DORSAL WING COLOR BY SEX OF EUROPEAN BUTTERFLIES. view more 

CREDIT: KALLE TUNSTRÖM

Butterflies have long captured our attention due to their amazing color diversity. But why are they so colorful? A new publication led by researchers from Sweden and Germany suggests that female influence butterfly color diversity by mating with colorful males.

In many species, especially birds and butterflies, males are typically more colorful than females, a phenomenon known as dichromatism. In many dichromatic species, the more conspicuous sex is more vulnerable to predation. Certainly, the male peacock is a much easier target than the more camouflaged hen. Explaining why one member of a species would place itself in more danger was a challenge to Charles Darwin's early views on evolution by natural selection, as Darwin envisioned natural selection acting to reduce such risks.

Examples of dichromatism in fact were one of the issues that lead him to develop his theory of sexual selection, where elaborate male traits could evolve through female preference for conspicuous males, even in the face of the increased dangers such males would encounter.

Today, many naturalists and biologists alike generally ascribe the exaggerated coloration of males as being due to sexual selection. However, when we see a species in which males are more colorful than females, sexual selection is not necessarily the only answer. An alternative route to dichromatism might begin with males and females both being very colorful, followed by natural selection acting upon females to make them less conspicuous, perhaps due to the cost of being easier prey. Stated another way, perhaps females become less colorful so they are better camouflaged and therefore preyed upon less. The argument that natural selection could give rise to dichromatism was posited by Darwin's contemporary, Alfred Russel Wallace. Darwin and Wallace in fact argued for decades about the origins of dichromatism in birds and butterflies.

The reason for this long debate between Darwin and Wallace arises because, without knowing how males and females looked in evolutionary past, either sexual selection or natural selection could give rise to dichromatism. Since they had no way of formally assessing what species used to look like, their argument had few routes for resolution.

This is where researchers from Sweden (Stockholm University and Lund University) and Germany (University of Marburg) have recently made progress, by developing statistical means for inferring the ancestral color states of males and females over evolutionary time.

To do this, they first reconstructed the evolutionary relationships among European butterflies and put this into a time calibrated framework. Then they scanned scientific drawings of all these male and female butterfly species, and used that color information in its evolutionary context to estimate the direction of butterfly color evolution for each sex, and in relation to the amounts of dichromatism per species. "Tracking evolutionary colour vectors through time made it possible to quantify both the male and female contribution to dichromatism", says Dr. Dirk Zeuss from the University of Marburg, who is coauthor of the new study.

"We find that the rates of color evolution in males are faster than in females", says Dr. Wouter van der Bijl, the lead author of the study. While this finding itself suggested that males might be the target of sexual selection, further analysis was needed to rule out alternative explanations. For example, male color could be evolving rapidly when species are already dichromatic, but not when males and females start to first diverge from each other in color. By modelling both the changes in dichromatism and the changes in male and female color over evolutionary time, the researchers could calculate that changes in male color are twice as important to the evolution of dichromatism than changes in female color.

This finding suggests that Darwin was right, as it is consistent with female preference and thus sexual selection for colorful males being the driving force in color evolution. Thus, the researchers provided some resolution to the 150-year-old argument between Darwin and Wallace about the origins of dichromatism in butterflies, finding that Darwin's, but not Wallace's, model of dichromatism evolution explains the patterns better.

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More information:

The article "Butterfly dichromatism primarily evolved via Darwin's, not Wallace's, model" is published in Evolution Letters:

https://onlinelibrary.wiley.com/doi/full/10.1002/evl3.199

Low-cost airlines have adapted best to COVID-19

UOC research analyses the long-term effects of low-cost carriers on European airports from 2001 to 2019

UNIVERSITAT OBERTA DE CATALUNYA (UOC)

Research News

 

The COVID-19 pandemic has caused a dramatic reduction in travel, especially to other countries. Figures show that in the second quarter of this year, airlines suffered an 80% fall in income compared to 2019, as the passenger fleet was brought to a virtual standstill, according to data from the International Air Transport Association.

Pere Suau-Sanchez is the research leader of the Sustainability and Management Research Group (SUMA) at the Universitat Oberta de Catalunya (UOC) Faculty of Economics and Business and an expert in air transport. According to his estimates, "COVID-19 has caused the biggest crisis in aviation history. For 2020, there will be a 50% fall in seat numbers for the airline industry, representing almost 3 billion fewer passengers and 400 billion dollars in loss of income".

Although these shocking figures affect the whole industry, low-cost airlines have proven more adaptable to this uncertain outlook, as Suau-Sanchez reports in his research published in the Journal of Transport Geography, in conjunction with Edgar Jimenez, from Cranfield University (United Kingdom).

According to the study, these airlines have shown greater resilience than traditional ones, due to their lower exposure to international long-haul traffic, which has been considerably disrupted by the health crisis.

Indeed, the fall in seat numbers offered in March and April 2020 was much sharper in traditional airlines than low-cost ones, while the recovery is similar in both, as travel restrictions are gradually lifted.

According to the UOC researcher, "Low-cost airlines operate in regional (intracontinental) markets and are therefore less exposed to the dynamics of long-haul (intercontinental) markets, which were the first to be grounded in early February and have remained inactive for longer due to government restrictions".

Exponential growth in less than a decade

The research is using new metrics to analyse the long-term effects of low-cost airlines on European airports. It also identifies the airports that have benefited most from the consolidation of these companies since 2001.

Generally, discussions on air traffic tend to use absolute figures, which fail to show the real situation of the airport, thus the authors have developed two new metrics. The first measures the offer of low-cost seats as a proportion of the total for the airport, i.e. the market share of these companies.

The second metric standardizes the low-cost market share in each individual airport in relation to the airport offering the highest number of low-cost seats. According to Suau-Sanchez, "this allows us to compare different years with a standard, comparable measurement".

After analysing all scheduled flights in Europe from 2001 to 2019, the research shows that in 2001 low-cost airlines represented 5.3% of total seats available on the market, or 37 million out of a total of 701 million seats.

Between 2001 and 2019, European air travel doubled its offer and the low-cost market grew exponentially: it increased its size by up to 14 times, so that by 2019 the companies represented 37.3% of total seats on offer, or 534 million out of a total of 1.43 billion seats.

Democratizing air transport

The research also shows how market concentration decreases once low-cost airlines arrive. The expert pointed out that "low-cost companies have democratized air transport in Europe and led the way in developing traffic in European airports".

The study also shows that the 2008 financial crisis marked a break in the growth of these companies. Furthermore, the data shows that eastern European countries saw the expansion in these airlines some years after the rest of Europe.

The UOC researcher said: "The later development of low-cost traffic in eastern Europe was linked to some of these countries joining the European Union in 2004 and 2007."

With regard to the future, bearing in mind this new post-pandemic scenario, Suau-Sanchez foresees the air industry having fewer companies, focusing its business on larger markets, with fewer business passengers. By way of conclusion, he said: "It should focus on economic and environmental sustainability in order to cope with an increasing number of changes."

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This UOC research project contributes towards Sustainable Development Goal (SDG) 9: Industry, Innovation and infrastructure.