Hubble Discovers Hydrogen-Burning White Dwarfs Enjoying Slow Ageing

To investigate the physics underpinning white dwarf evolution, astronomers compared cooling white dwarfs in two massive collections of stars: the globular clusters M3 and M13. These two clusters share many physical properties such as age and metallicity but the populations of stars which will eventually give rise to white dwarfs are different. This makes M3 and M13 together a perfect natural laboratory in which to test how different populations of white dwarfs cool.
Image credit: ESA/Hubble & NASA, G. Piotto et al.

Could dying stars hold the secret to looking younger? New evidence from the NASA/ESA Hubble Space Telescope suggests that white dwarfs could continue to burn hydrogen in the final stages of their lives, causing them to appear more youthful than they actually are. This discovery could have consequences for how astronomers measure the ages of star clusters.

The prevalent view of white dwarfs as inert, slowly cooling stars has been challenged by observations from the NASA/ESA Hubble Space Telescope. An international group of astronomers have discovered the first evidence that white dwarfs can slow down their rate of ageing by burning hydrogen on their surface.

“We have found the first observational evidence that white dwarfs can still undergo stable thermonuclear activity,” explained Jianxing Chen of the Alma Mater Studiorum Università di Bologna and the Italian National Institute for Astrophysics, who led this research. “This was quite a surprise, as it is at odds with what is commonly believed.”

White dwarfs are the slowly cooling stars which have cast off their outer layers during the last stages of their lives. They are common objects in the cosmos; roughly 98% of all the stars in the Universe will ultimately end up as white dwarfs, including our own Sun [1]. Studying these cooling stages helps astronomers understand not only white dwarfs, but also their earlier stages as well.

To investigate the physics underpinning white dwarf evolution, astronomers compared cooling white dwarfs in two massive collections of stars: the globular clusters M3 and M13 [2]. These two clusters share many physical properties such as age and metallicity [3] but the populations of stars which will eventually give rise to white dwarfs are different. In particular, the overall colour of stars at an evolutionary stage known as the Horizontal Branch are bluer in M13, indicating a population of hotter stars. This makes M3 and M13 together a perfect natural laboratory in which to test how different populations of white dwarfs cool.

“The superb quality of our Hubble observations provided us with a full view of the stellar populations of the two globular clusters,” continued Chen. “This allowed us to really contrast how stars evolve in M3 and M13.”

Using Hubble’s Wide Field Camera 3 the team observed M3 and M13 at near-ultraviolet wavelengths, allowing them to compare more than 700 white dwarfs in the two clusters. They found that M3 contains standard white dwarfs which are simply cooling stellar cores. M13, on the other hand, contains two populations of white dwarfs: standard white dwarfs and those which have managed to hold on to an outer envelope of hydrogen, allowing them to burn for longer and hence cool more slowly.

Comparing their results with computer simulations of stellar evolution in M13, the researchers were able to show that roughly 70% of the white dwarfs in M13 are burning hydrogen on their surfaces, slowing down the rate at which they are cooling. 

This discovery could have consequences for how astronomers measure the ages of stars in the Milky Way. The evolution of white dwarfs has previously been modelled as a predictable cooling process. This relatively straightforward relationship between age and temperature has led astronomers to use the white dwarf cooling rate as a natural clock to determine the ages of star clusters, particularly globular and open clusters. However, white dwarfs burning hydrogen could cause these age estimates to be inaccurate by as much as 1 billion years.

“Our discovery challenges the definition of white dwarfs as we consider a new perspective on the way in which stars get old,” added Francesco Ferraro of the Alma Mater Studiorum Università di Bologna and the Italian National Institute for Astrophysics, who coordinated the study. “We are now investigating other clusters similar to M13 to further constrain the conditions which drive stars to maintain the thin hydrogen envelope which allows them to age slowly”. 

Notes

[1] The Sun is only 4.6 billion years through its roughly 10-billion-year lifetime. Once it exhausts hydrogen in its core, the Sun will swell into a red giant, engulfing the inner planets and searing the Earth’s surface. It will then throw off its outer layers, and the exposed core of the Sun will be left as a slowly cooling white dwarf. This stellar ember will be incredibly dense, packing a large fraction of the mass of the Sun into a roughly Earth-sized sphere.

[2] M3 contains roughly half a million stars and lies in the constellation Canes Venatici. M13 — occasionally known as the Great Globular Cluster in Hercules — contains slightly fewer stars, only several hundred thousand. White dwarfs are often used to estimate the ages of globular clusters, and so a significant amount of Hubble time has been dedicated to exploring white dwarfs in old and densely populated globular clusters. Hubble directly observed white dwarfs in globular star clusters for the first time in 2006.

[3] Astronomers use the word “metallicity” to describe the proportion of a star which is composed of elements other than hydrogen and helium. The vast majority of matter in the Universe is either hydrogen or helium — to take the Sun as an example, 74.9% of its mass is hydrogen, 23.8% is helium, and the remaining 1.3% is a mixture of all the other elements, which astronomers refer to as “metals”

Source/Credit: ESA/Hubble

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Hidden air pollutants on the rise in cities in India and the UK

 

Satellite data helped researchers discover rising
 levels of air pollutants

Levels of air pollutants in cities in India are on the rise, according to scientists using observations from instruments on satellites that scan the global skies every day.

Researchers used a long record of data gathered by space-based instruments to estimate trends in a range of air pollutants for 2005 to 2018, timed to coincide with well-established air quality policies in the UK and rapid development in India.

The study was led by the University of Birmingham and UCL and included an international team of contributors from Belgium, India, Jamaica and the UK. The researchers published their findings in the journal Atmospheric Chemistry and Physics, noting that fine particles (PM2.5) and nitrogen dioxide (NO2), both hazardous to health, are increasing in Kanpur and Delhi.

Delhi is a fast-growing megacity and Kanpur was ranked by the WHO in 2018 as the most polluted city in the world. The researchers speculated that increases in PM2.5 and NO2 in India reflect increasing vehicle ownership, industrialization and the limited effect of air pollution policies to date.

This contrasts with trends in the UK cities London and Birmingham, which show modest but ongoing declines in PM2.5 and NOx, reflecting the success of policies targeting sources that emit these pollutants.

They also found increases in the air pollutant formaldehyde in Delhi, Kanpur and London. Formaldehyde is a marker for emissions of volatile organic compounds that include a large contribution from vehicle emissions in India, and, in the UK, an increasing contribution from personal care and cleaning products and a range of other household sources.

Karn Vohra, study lead author and PhD student at the University of Birmingham, commented: “We wanted to demonstrate the utility of satellite observations to monitor city-wide air pollution in the UK where ground-based measurements are in abundance and in India where they are not. Our approach will be able to provide useful information about air quality trends in cities with limited surface monitoring capabilities. This is critical as the WHO estimates that outdoor air pollution causes 4.2 million deaths a year."

Study co-author Professor William Bloss, also from the University of Birmingham, commented “We were surprised to see the increase in formaldehyde above Delhi, Kanpur and London – a clue that emissions of other volatile organic compounds may be changing, potentially driven by economic development and changes in domestic behavior. Our results emphasize the need to monitor our air for the unexpected, and the importance of ongoing enforcement of measures for cleaner air.”

“There is more than a decade of freely available observations from instruments in space to monitor and assess air quality in cities throughout the world. Greater use of these in the UK, India, and beyond is paramount to successful air quality policies”, stated Dr Eloise Marais, Earth observation expert at UCL and conceptual lead of the study.

Source/Credit: University of Birmingham

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Blue-tongue vs red-bellied black

 

Scientists have discovered that the humble blue-tongue lizard is largely resistant to the venom of the deadly red-bellied black snake, while giant carnivorous monitor lizards which feed on Australia’s most venomous snakes are not.

The surprising finding was revealed after University of Queensland scientists compared the effects of various reptile blood plasmas when exposed to the venom.

UQ PhD candidate Nicholas Youngman said mammalian – and particularly, human – reactions had been heavily investigated, but very little was known about snake venom effects on other reptiles.

“It was a shock discovering that the eastern blue-tongue, along with the shingleback, showed resistance specifically to red black snake venom,” Mr Youngman said.

“Since their resistance was so specific to only this snake species, it seems these lizards have evolved a special plasma component – known as a serum factor – in their blood.

“This prevents specific toxins in red-bellied black snake venom from clotting the lizards’ plasma, which would lead to a rapid death in most other animals.

“This resistance doesn’t mean they’re completely immune, but it would give them a greater chance of survival, allowing them to escape or fight back.

“Much like how a COVID-19 vaccine doesn’t mean you don’t get sick at all, it just means you are less likely to die.”

The research team analyzed the effects of seven different Australian snake venoms on the plasma of two species of blue-tongued skinks and three species of monitor lizards that would interact with these snakes in the wild.

Associate Professor Bryan Fry, who heads UQ’s Venom Evolution Lab, said the results also revealed that monitor lizards – or goannas – were not resistant to the snake venoms.

“You’d think that a goanna would be significantly resistant to the venom of any snake it was hunting and eating, but that isn’t the case,” Dr Fry said.

“Snake venom can only cause harm to goannas if it’s injected into its body by the snake’s fangs, it can’t be absorbed directly through the skin.

“Goannas are heavily armored and their scales act like medieval chain mail, with each containing a piece of bone, meaning venomous snakes’ fangs struggle to pierce this armor.

“So – unlike the slow, vulnerable blue-tongue lizard – there’s no pressure for goannas to evolve resistance; natural selection has invested in their armor and it’s clearly working for them.

“These two divergent forms of resistance are fascinating examples of evolutionary novelty.”

The research has been published in Toxins

Source/Credit: University of Queensland

bio090621_01

How climatic changes influence the evolution of oceanic insects

Research team members (from left)
Mr Marc Chang and Assistant Professor Danwei Huang
examining ocean skater specimens

The open oceans are harsh and hostile environments where insects might not be expected to thrive. In fact, only one insect group, ocean skaters, or water striders, has adapted to life on the open seas.

How these insects evolved to conquer the high seas, however, was not known.

Now, a study of the genetics of skaters provides a clue. The answer has to do with when major currents in the eastern Pacific Ocean came into existence with each species of skater evolving to match the unique conditions of those currents.

Scientists from the National University of Singapore (NUS) and Scripps Institution of Oceanography at UC San Diego examined the genetics of three ocean skater species collected with dip nets across the eastern Pacific between Hawaii and Peru. The results of the study revealed that the skaters became specialized on different current systems, as those currents changed into their modern configurations.

The findings could unravel the mystery of how each skater species came to occupy habitats vastly different from those of other insects, and also deepen our understanding of how climate change affects ocean-dwelling organisms.

“It is amazing how the ocean skater’s genetic history is closely tied to that of our oceans,” said study leader Dr Wendy Wang, an entomologist from the Lee Kong Chian Natural History Museum at NUS. “The open ocean is an extremely hostile environment, with direct sunlight throughout the daytime, strong winds and limited food. The abilities of their body covering or cuticle to protect their internal organs from heat and ultraviolet damage, and to survive violent storms and find food in this unique habitat where no other insect could demonstrate their unique ecological roles in the ocean. These characteristics make them fascinating subjects of study for materials science and extreme biological adaptations.”

The research team first reported their findings in the journal Marine Biology on 5 September 2021.

Linking genetic data with climatic changes

Ocean skaters live their entire lives perpetually running about on the surface film of the open seas, enduring lashing storms and feeding on tiny prey trapped on or just below the ocean surface. Currently, there are five known oceanic species of the genus Halobates. While information about where they can be found are well-established, little is known about their genetic variation, and how physical factors like ocean currents, temperature and winds affect their distribution.

The research team conducted a genetic study of three of those skater species collected from offshore Mexico to Peru, and as far out to sea as Hawaii. Most of the specimens were skimmed from the ocean surface with dip nets by Dr Lanna Cheng, a marine biologist at Scripps Oceanography, and study co-author. Dr Cheng is a world expert who has devoted her research to Halobates, and she has been studying the genus for almost five decades.

Dr Wang led the gene sequencing and genetic analysis of nearly 400 specimens across the three species. The researchers uncovered distinct genetic variations among the species that illustrate very different stories of population growth and development during ancient times.

The oldest of them, Halobates splendens, was found to have expanded its population nearly a million years ago. The other two younger species, Halobates micans and Halobates sobrinus, were found to have increased in abundance 100,000 to 120,000 years ago.

These formative dates match past climate events. H. splendens is now found in the rich, productive waters of the cold tongue that originates off the coast of South America as the Peru current. Climatological data showed that this physical feature of cold surface water came into existence a million years ago, just at the same time as the period of growth in the genetic diversity and populations of H. splendens.

The other two species H. sobrinus and H. micans were determined to have diversified in the warm, relatively unproductive waters of Central America. The populations of both species expanded when El Niño climate patterns caused warm ocean water to move into the eastern Pacific Ocean. The El Niño effects were especially strong in the habitats of both H. micans and H. sobrinus about 100,000 years ago, coinciding with the time these species developed their modern genetic patterns and population sizes.

“With no apparent physical boundaries in the open ocean to stop them, Halobates can skate practically from the coast of California across the entire Pacific Ocean to Japan and beyond,” Dr Cheng said. “Two of the species studied in this paper, H. sobrinus and H. splendens, however, have never been found to venture beyond the eastern Pacific Ocean and we didn't know why. This paper gave us the clue from their ancestry."

Scripps Oceanography’s Professor Richard Norris is a paleontologist who, for the study, matched the expansion of ocean skater populations to the time periods when the fossil record suggests the modern currents first formed.

“The genetics show that the three species we studied each had periods of population growth that fit eerily well with geological evidence for when the current systems they live in came into existence,” said Prof Norris. “Perhaps I shouldn’t be surprised, since it is common for marine creatures to specialize on particular ocean conditions, but these skaters live on top of the ocean. Apparently, even the character of the sea spray and water surface film is different enough between currents to matter to these guys.”

Further research

Dr Wang elaborated, “The findings of our study highlight the deep influence of climatic conditions on marine populations. The results also contribute towards understanding the fates of ocean-dwelling organisms as ongoing climate change accelerates in the coming decades.”

To expand their knowledge, the researchers will continue to examine the population dynamics of this enigmatic marine insect by studying their genomes.

“Drawing on the key insights from this study, together with our ongoing work, we aim to connect the evolutionary origins of various Halobates species, and uncover how they came to occupy the surface ocean and coastal habitats in present day,” shared marine biologist and co-author Assistant Professor Huang Danwei from the NUS Department of Biological Sciences, and an alumnus of Scripps Oceanography.

Co-author Mr Marc Cheng added, “Having genetic data is especially useful for organisms such as the ocean skaters which we are studying as we are unable to observe them ethologically in their natural environment to track their population.” He is a doctoral student at NUS who is using DNA sequencing methods to uncover the genetic basis to life on the sea surface.

Source/Credit: National University of Singapore

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From racehorse to therapy horse

 

Photo by Jennifer Murray from Pexels

A new study will examine the selection, training and welfare of thoroughbred horses as they transition from racetrack to therapy horse. The pioneering project, led by academics at the University of Bristol’s Veterinary School in collaboration with Racing to Relate, will develop a recognized global welfare standard for former racehorses who are moving into Equine Assisted Therapy (EAT).

Thoroughbreds are recognized for their sensitivity and this project will provide a research-based approach to retraining them for therapy work. EAT careers could include work with a diverse group of people, from veterans and disabled children to those struggling with mental health issues. The research, which is funded by the John Pearce Foundation, is the first of its kind to study EAT across many countries and will look at practices in the UK, USA, France and Ireland, to understand the impact of EAT on the horses.

Claire Neveux, Bristol Vet School PhD student for the project, said: "I have worked with thoroughbreds for about 20 years, mainly with broodmares and young horses, and I have always been amazed by their high reactivity and sensitivity. I'm also fascinated by the human-horse relationship. I had a few opportunities to participate in Equine Assisted Therapy programs as an intern during my graduate studies. That's why, when I met Jennifer Twomey from Racing to Relate, I took the opportunity to be part of this pioneering and collaborative project, and I'm thrilled to contribute to this research. I'm convinced that a better understanding of the thoroughbred personality traits and suitability of horses for EAT is essential for equine and human welfare."

The main aim of the research is to create a create a global standard for selection and training, to help the racing industry to improve welfare support for off-track racehorses going into a career in EAT. The research will help industry and stakeholders to improve Thoroughbred welfare through a successful transition to their new career in EAT.

Little research has been carried out on the welfare of horses within EAT programs, and especially on the impact it may have on their wellbeing. In particular, this research will analyze the educational process for all horses within the EAT sector, to gain a clearer picture of why and how horses are selected for particular roles. The aim is to fully understand the current selection and training methods within the sector and identify specific characteristics of the thoroughbred, which are suited to a career in EAT. The study will also explore details of the life and routine of equines within EAT, examining existing perceptions and considerations of horse welfare.

Dr Mathilde Valenchon, Research Fellow at the Bristol Vet School and co-supervisor of the PhD project, added: "I am delighted we successfully developed this research project to understand and facilitate the involvement of ex-racehorses in EAT activities. I have been studying equine behaviour, cognition and welfare for the past 12 years. I have always been impressed by the thoroughbred's sensitivity and adaptability. I am thrilled to contribute to a better knowledge of their suitability for EAT and the development of standards, as this will significantly and positively impact the horses' welfare, as well as people’s. I am especially proud that our research includes the horse's perspective."

Dr Siobhan Mullan, Senior Research Fellow at Bristol Vet School, and co-supervisor of the PhD project, said: "Thoroughbred horses involved in EAT programs are performing a really special and valuable role in society, and yet little formal research has been done to understand how to optimize their welfare throughout their transition from racehorse to therapy horse and in the course of their new career. I'm heartened by the interest around the world in using the results of our research to develop standards which will have a long-lasting impact on horse welfare."

Source/Credit: University of Bristol

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Fruits, vegetables sold in U.S. are products of forced labor

 

A study published in Nature Food involving academics at The University of Nottingham calls attention to the need for better systems to track forced labor in food supply chains.

The study reports on the development of a new scoring system that identifies the risk of forced labor for fruits and vegetables sold in the United States. It finds a high risk of forced labor, but also scattered and incomplete data sources that limit action.

The study was led by Dr Nicole Tichenor Blackstone in the Agriculture, Food and Environment program at the Friedman School of Nutrition Science & Policy at Tufts, and Dr Jessica Decker Sparks, Associate Director at the University of Nottingham Rights Lab, leading its Ecosystems and Environment Program.

“Sustainability research on the food supply typically focuses on promoting human health and protecting the environment,” said first and corresponding author Dr Blackstone. “But social sustainability provides a different perspective on our food sources, including issues of labor rights and equity. Globally, agriculture has one of the highest incidences of forced labor.”

Responsible procurement

The study developed a new forced labor risk scoring method that draws upon original data compiled by the authors as well as a range of governmental and non-profit data. The research team then coded each food and country-of-origin combination as either very high risk, high risk, medium risk, or low risk for forced labor having occurred at some point in the growing and harvesting of each item. Previously, there have been short lists of commodities suspected of being produced with forced labor, or case studies of foods produced in one country, such as Mexico.

“What we’ve done, for the first time, is to look at all of the major fruits and vegetables consumed in the U.S., as well as all of the countries these foods come from, including the U.S., and assess the possibility that somewhere in the production process forced labor could have been involved,” said Dr Blackstone.

The scoring method is not meant to be a consumer tool but could help industry and policy makers interested in the development of systems and protocols for the responsible procurement of foods.

The final data set included 93 fruits and vegetables in 307 food-country combinations. The results of the qualitative coding show that most food-country combinations were coded as high risk (85%) for forced labor at some point. Seven percent were coded as very-high risk, 4.5% were coded as medium risk, and 3.5% were coded as low risk.

“This is an extraordinary percentage at high risk, but it reflects that there are very limited or coarse data,” said senior author Dr Sparks. “There are major structural issues with how agricultural labor is set up that make workers vulnerable. To us, this reflects systemic issues in food supply chains that have not been addressed."

Agricultural work often takes place in remote and isolated environments with demanding labor requirements. There are typically inadequate legal protections, with piece-rate pay systems tied to productivity, and reliance on migrant labor.

As defined by the International Labor Organization, “forced labor can be understood as work that is performed involuntarily and under the menace of any penalty. It refers to situations in which persons are coerced to work through the use of violence or intimidation, or by more subtle means such as manipulated debt, retention of identity papers or threats of denunciation to immigration authorities.”

“Forced labor in agriculture is a threat to the sustainability of food systems. However, the scarcity of data noted limits holistic analysis and action. Future research should prioritize data and model development to enable analyses of forced labor and other labor-related social risks (e.g., wages, child labor) across the life cycles of a wide range of foods. These efforts can help ensure that the rights and dignity of “the hands that feed us” are centered in the transformation of food systems,” concluded the authors in the study.

Source/Credit: University of Nottingham

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Coronavirus Epidemics first hit more than 21,000 years ago

 

Sarbecoviruses have crossed into humans twice in the last decade, leading to the deadly SARS-CoV-1 outbreak in 2002-04 and the current COVID-19 pandemic, caused by the SARS-CoV-2 virus.  A new Oxford University Study, published today, shows that the most recent common ancestor of these viruses existed more than 21,000 years ago, nearly 30 times older than previous estimates.

‘Finding the evolutionary origins of pandemic viral infections such as COVID-19 help us understand how long humanity may have been exposed to these viruses, how frequently they might have caused disease outbreaks in the past, and how likely they might be to cause novel outbreaks in future.’ Said Prof Katzourakis, who led the work.

Despite having a very rapid rate of evolution over short timescales, to survive, viruses must remain highly adapted to their hosts - this imposes severe restrictions on their freedom to accumulate mutations without reducing their fitness. This causes the apparent rate of evolution of viruses to slow down over time. The new research, for the first time, successfully recreates the patterns of this observed rate decay in viruses. 

‘We developed a new method that can recover the age of viruses over longer timescales and correct for a kind of ‘evolutionary relativity’, where the apparent rate of evolution depends on the timescale of measurement. Our estimate based on viral sequence data, of more than 21,000 years ago, is in remarkable concordance with a recent analysis on human genomic dataset that suggests infection with an ancient coronavirus around the same time.’ Said Mahan Ghafari, from Oxford University.

The study also demonstrates that while existing evolutionary models have often failed to measure the divergence between virus species over periods - from a few hundred to a few thousands of years - the evolutionary framework developed in this study will enable the reliable estimation of virus divergence across vast timescales, potentially over the entire course of animal and plant evolution. 

The new model enables us to not only reconstruct the evolutionary history of viruses related to SARS-CoV-2, but also a much wider range of RNA and DNA viruses during more remote periods in the past. 

The model predictions for hepatitis C virus - a leading global cause of liver disease - are consistent with the idea that it has circulated for nearly a half a million years. HCV may thus have spread worldwide as an intrinsic part of the “Out-of-Africa” migration of modern humans around 150,000 years ago. 

The different genotypes of HCV indigenous to human populations in South and South-East Asia and Central Africa may have originated over this prolonged period and this revised timescale may resolve the longstanding riddle of their global distributions. 

‘With this new technique we can look much more widely at other viruses; re-evaluate the timescales of their deeper evolution and gain insights into host relationships that are key to understanding their ability to cause disease.’ Prof Simmonds, Oxford University

Source / Credit: University of Oxford

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Birds and mammals evolve faster if their home is rising

 

Wild Kea, New Zealand  Credit: Pablo Heimplatz

Researchers at the University of Cambridge have combined reconstructions of the Earth’s changing surface elevations over the past three million years with data on climate change over this timeframe, and with bird and mammal species’ locations. Their results reveal how species evolved into new ones as land elevation changed - and disentangle the effects of elevation from the effects of climate.

The study found that the effect of elevation increase is greater than that of historical climate change, and of present-day elevation and temperature, in driving the formation of new species – ‘or speciation’.

In contrast to areas where land elevation is increasing, elevation loss was not found to be an important predictor of where speciation happens. Instead, present-day temperature is a better indicator of speciation in these areas.

The results are published in the journal Nature Ecology and Evolution.

“Often at the tops of mountains there are many more unique species that aren’t found elsewhere. Whereas previously the formation of new species was thought to be driven by climate, we’ve found that elevation change has a greater effect at a global scale,” said Dr Andrew Tanentzap in the University of Cambridge’s Department of Plant Sciences, senior author of the paper.

As land elevation increases, temperature generally decreases and habitat complexity increases. In some cases, for example where mountains form, increasing elevation creates a barrier that prevents species moving and mixing, so populations become reproductively isolated. This is the first step towards the formation of new species.

The effect of increasing elevation on that rate of new species formation over time was more pronounced for mammals than for birds; the researchers think this is because birds can fly across barriers to find mates in other areas. Birds were affected more by present-day temperatures; in birds, variation in temperature creates differences in the timing and extent of mating, risking reproductive isolation from populations of the same species elsewhere.

Until now, most large-scale studies into the importance of topography in generating new species have only considered present-day land elevation, or elevation changes in specific mountain ranges.

“It’s surprising just how much effect historical elevation change had on generating the world’s biodiversity – it has been much more important than traditionally studied variables like temperature. The rate at which species evolved in different places on Earth is tightly linked to topography changes over millions of years,” said Dr Javier Igea in the University of Cambridge’s Department of Plant Sciences, first author of the paper.

He added: “This work highlights important arenas for evolution to play out. From a conservation perspective these are the places we might want to protect, especially given climate change. Although climate change is happening over decades, not millions of years, our study points to areas that can harbor species with greater potential to evolve.”

The researchers say that as the Earth’s surface continues to rise and fall, topography will remain an important driver of evolutionary change.

This research was funded by Wellcome, the Gatsby Charitable Foundation and the Isaac Newton Trust.

Source/Credit: University of Cambridge

en090321_02

Warming Atlantic forces whales into new habitats, danger

 

Source: Pexels

Warming oceans have driven the critically endangered North Atlantic right whale population from its traditional and protected habitat, exposing the animals to more lethal ship strikes, disastrous commercial fishing entanglements and greatly reduced calving rates.

Without improving its management, the right whale populations will decline and potentially become extinct in the coming decades, according to a Cornell- and University of South Carolina-led report in the Sept. 1 journal Oceanography.

“Most of the warming in the Gulf of Maine is not coming from the atmosphere or ocean surface, as one may think,” said senior author Charles Greene, professor emeritus in the Department of Earth and Atmospheric Sciences in the College of Agriculture and Life Sciences. “It is coming from invading slope water many hundreds of feet below the ocean surface, forcing the right whales to abandon their traditional habitat.”

Since 2010, the calving rate has declined and the right whale population has dropped by an estimated 26%, according to the paper. At the beginning of the decade, the North Atlantic right whale population had numbered over 500. Now, the North Atlantic Right Whale Consortium estimates the population at just 356 whales.

The species is considered critically endangered by the International Union for Conservation of Nature Red List of Threatened Species.

Individual whales are not interchangeable; each right whale has its own name and personality, and scientists know them quite well. The whales have been given monikers including Tux, Popcorn, Arrow and Sundog. When scientists spot the right whales, they log the sighting into an international catalog for a perpetually updated census.

“Right whales are one of the best studied, best understood populations in the ocean,” said Greene., a faculty fellow at the Cornell Atkinson Center for Sustainability. “We basically know every individual. It’s very rare that you can study a population where you know everybody.”

And when the right whales have run-ins with humans, such as large ships or commercial fishing lines, scientists can easily identify their carcasses.

The warm slope water entering the Gulf of Maine at depth derives its heat from the Gulf Stream. As the tail end of the Atlantic Meridional Overturning Circulation, the Gulf Stream has changed its trajectory dramatically during the past ten years.

“Due to a warming climate, the Atlantic Meridional Overturning Circulation is slowing down, causing the Gulf Stream to move North, injecting warmer and saltier slope water into the Gulf of Maine,” Greene said.

The warming Gulf of Maine has reduced the abundance of copepods, the tiny crustaceans that serve as the right whales’ favorite snack. This has reduced right whale calving rates and forced the whales to abandon their mid-summer feeding grounds in the Gulf of Maine. Instead, the whales have headed north to the cooler waters of the Gulf of St. Lawrence.

Since 2015, scientists have witnessed an increased number of right whales feeding in the Gulf of St. Lawrence, where there were no protections in place to prevent ship strikes and fishing gear entanglement. This has led to an Unusual Mortality Event declared by NOAA in 2017, when 17 right whale deaths were confirmed, mostly in the Gulf of St. Lawrence. Ten right whales were found dead in 2019, while for 2020 and 2021, four deaths have occurred thus far.

“Right whales continue to die each year,” said lead author Erin Meyer-Gutbrod, Ph.D. ’16, assistant professor at the University of South Carolina. “Protective policies must be strengthened immediately before this species declines past the point of no-return.”

Ocean scientists are hoping for new policies on rope-free fishing gear, vessel speed limit enforcement and money for monitoring and ecosystem forecasting.

“Right whale populations can shift quickly and unexpectedly in our changing climate,” Meyer-Gutbrod said. “There is no time to waste.”

In addition to Greene and Meyer-Gutbrod, co-authors on the research, “Ocean Regime Shift is Driving Collapse of the North Atlantic Right Whale Population,” are Kimberley T.A. Davies, assistant professor, University of New Brunswick, Canada; and David G. Johns, head of the Continuous Plankton Recorder Survey, Marine Biological Association of the United Kingdom, Plymouth, United Kingdom.

Funding for this research was provided by the Lenfest Ocean Program.

Source/Credit: Cornell University / Blaine Friedlander

en090321_01

Discovery paves way for improved quantum devices

 

Schematic of a superconducting circuit [thin black lines] on a silicon chip [yellow base], being imaged using terahertz scanning near-field microscopy [red beam focused into yellow tip].

Physicists and engineers have found a way to identify and address imperfections in materials for one of the most promising technologies in commercial quantum computing.

The University of Queensland team was able to develop treatments and optimize fabrication protocols in common techniques for building superconducting circuits on silicon chips.

Dr Peter Jacobson, who co-led the research, said the team had identified that imperfections introduced during fabrication reduced the effectiveness of the circuits.

"Superconducting quantum circuits are attracting interest from industry giants such as Google and IBM, but widespread application is hindered by ‘decoherence’, a phenomenon which causes information to be lost,” he said.

“Decoherence is primarily due to interactions between the superconducting circuit and the silicon chip – a physics problem – and to material imperfections introduced during fabrication – an engineering problem.

“So we needed input from physicists and engineers to find a solution.”

 The team used a method called terahertz scanning near-field optical microscopy (THz SNOM) – an atomic force microscope combined with a THz light source and detector.

This provided a combination of high spatial resolution – seeing down to the size of viruses – and local spectroscopic measurements.

Professor Aleksandar Rakić said the technique enabled probing at the nanoscale rather than the macroscale by focusing light onto a metallic tip.  

“This provides new access for us to understand where imperfections are located so we can reduce decoherence and help reduce losses in superconducting quantum devices,” Professor Rakić said.

“We found that commonly used fabrication recipes unintentionally introduce imperfections into the silicon chips, which contribute to decoherence.

“And we also showed that surface treatments reduce these imperfections, which in turn reduces losses in the superconducting quantum circuits.”

Associate Professor Arkady Fedorov said this allowed the team to determine where in the process defects were introduced and optimize fabrication protocols to address them.

“Our method allows the same device to be probed multiple times, in contrast to other   methods that often require the devices to be cut up before being probed,” Dr Fedorov said.

“The team’s results provide a path towards improving superconducting devices for use in quantum computing applications.”

In future, THz SNOM could be used to define new ways to improve the operation of quantum devices and their integration into a viable quantum computer.

The results are published in Applied Physics Letters

News Release
Source/Credit: University of Queensland

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