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The virus appears to be making people’s blood much more sticky, medical experts say.
The new coronavirus isn’t just attacking the lungs: New research shows it’s causing harm to the gastrointestinal tract, especially in more advanced cases of Covid-19.
A variety of imaging scans performed on hospitalised Covid-19 patients showed bowel abnormalities, according to a study published online on 11 May in Radiology. Many of the effects were severe and linked with clots and impairment of blood flow.
“Some findings were typical of bowel ischaemia, or dying bowel, and in those who had surgery we saw small vessel clots beside areas of dead bowel,” said study lead author Dr Rajesh Bhayana, who works in the department of radiology at Massachusetts General Hospital in Boston.
“Patients in the ICU can have bowel ischaemia for other reasons, but we know Covid-19 can lead to clotting and small vessel injury, so bowel might also be affected by this,” Bhayana explained in a journal news release.
Multisystem involvement
One expert unconnected to the new study said the findings aren’t surprising.
“Our emerging understanding of Covid-19 has found the disease to have multisystem involvement including the nervous, cardiac, vascular [excess clotting] and finally the digestive systems, among others,” said Dr Sherif Andrawes. He directs endoscopy in the division of gastroenterology and haematology at Staten Island University in New York City.
“It seems that this disease is intricate, in the sense that it can involve multiorgan systems, rather than being a disease of the respiratory system solely,” Andrawes said.
In fact, a study published online on 13 May in the journal Science Immunology has found evidence that SARS-CoV-2, the virus behind Covid-19, can infect the human digestive system.
Researchers led by Siyuan Ding of Washington University School of Medicine in St. Louis, said their findings “highlight the intestine as a potential site of SARS-CoV-2 replication, which may contribute to local and systemic illness and overall disease progression”.
That seems to be borne out by the Boston study.
Preliminary study
That research included 412 Covid-19 patients who were hospitalised between 27 March and 10 April. They averaged 57 years of age, and 134 of them underwent abdominal imaging, including 137 radiographs, 44 ultrasounds, 42 CT scans, and one MRI.
Abnormalities of the bowel wall (intestines and colon) were detected on 31% of CT scans and were more common among patients in intensive care than in other patients, the findings showed.
Bowel abnormalities included thickening and ischaemia – restricted blood flow due to a clot. Surgery was conducted in four patients with bowel abnormalities detected on scans, and it revealed an unusual yellow discolouration of the bowel in three patients, plus bowel infarction (“dead bowel,” caused by reduction in blood supply) in two.
The researchers said possible explanations for bowel abnormalities in Covid-19 patients include direct infection by the new coronavirus; clots arising in small vessels that supply the bowel with blood; or what’s known as “nonocclusive mesenteric ischaemia” – a condition caused by inadequate blood supply to the intestines.
“Our study is preliminary, and more work is needed to understand the cause of bowel findings in these patients,” Bhayana cautioned in a journal news release.
For his part, Andrawes agreed that severe gastrointestinal symptoms are appearing in some Covid-19 patients.
Life-threatening bowel issues
“Patients with predominantly respiratory symptoms may also have mild symptoms of nausea, vomiting and diarrhoea,” he said. But in the new study, “a subgroup of Covid-19 patients was found to have more involvement of the gastrointestinal tract with intense symptoms of nausea, vomiting and diarrhoea leading to dehydration and less severe upper respiratory symptoms,” Andrawes said, and their stool also tested positive for traces of the new coronavirus.
In some cases of Covid-19, gastrointestinal issues may even arise before the respiratory tract is affected.
So, “patients with new-onset of digestive symptoms after possible contact with Covid-19 or connection with a Covid-19 case should be investigated for Covid-19 illness, even in the absence of the more common upper respiratory symptoms of cough, fever and shortness of breath,” Andrawes advised.
Dr David Bernstein is chief of hepatology at the Northwell Health’s Sandra Atlas Bass Center for Liver Diseases in Manhasset, New York. Reading over the new study, he said that it’s “concerning” that patients are developing life-threatening bowel issues, probably due to clots within the bowel that are cutting off the organ’s blood supply.
This should “remind Covid-19 health care providers about the critical use of anticoagulant therapy early on in the disease, in an effort to prevent life-threatening complications such as bowel ischaemia and pulmonary embolism [clots],” Bernstein said.
Image credit: Getty Images
At the beginning of May, South Africa entered Level 4, the second phase of its National Covid-19 lockdown. Some regulations setting out what people may and may not do under level 4 have been controversial and government has been criticised from various of quarters.
President Cyril Ramaphosa addressed the nation on Wednesday evening (13 May) and admitted that the government has at times “fallen short” of the country’s expectation.
“Some of the actions we have taken have been unclear, some have been contradictory, and some have been poorly explained. Implementation has sometimes been slow, and enforcement has sometimes been inconsistent and too harsh,” he said.
Ramaphosa also indicated that some regulations may change in the coming days and that most of the country should be on a level 3 lockdown by the end of May.
Spotlight spoke to six health experts about the rationale behind some of the most controversial of the current regulations.
Professor Landon Myer, Director and Head of the School of Public Health & Family Medicine at the University of Cape Town, stressed that there are no clear right answers.
“The clear driver of all the problems, is that we don’t know enough about the epidemiology of the virus to know exactly what is going to be the most effective strategies,” he said.
“So, the government is having to make decisions with imperfect insight.”
“In retrospect everything will look obvious, that some things were right, and some things were wrong… That doesn’t mean I agree with everything, but I think that it is important to note that,” said Myer.
Professor Shaheen Mehtar, a retired professor of Infection Control and former chair of the Infection Control Africa Network, told Spotlight that the recent regulations were all based on evidence.
“The ones (regulations) that have emerged in the last month or so are all evidence based… there isn’t any one (regulation) that is pointless,” she said.
Mehtar is on the Ministerial Advisory Committee on Covid-19 chaired by Professor Salim Abdool Karim. However, Mehtar agreed that there are things that can be improved and added to the regulations.
“We need to strengthen the infection control side of things. We need to strengthen the role of the infection prevention committees at health care facility levels,” she said.
Russell Rensburg, director of the Rural Health Advocacy Project (RHAP) expressed concern about the lack of clarity on what process the government is following when it makes decisions.
“What we should be focusing on is what is government’s process and how can it be improved. Because at the moment we’re in uncharted territory… How do they achieve decisions as a collective? How do they record dissenting views? On what basis do they pass the regulations?” Rensburg asked.
Shafrudeen Amod, a health law expert and infectious disease scholar from KwaZulu-Natal, has similar concerns.“I think there are ways to make it better. I feel like there hasn’t been a lot of thought that has gone into some of these regulations.
“For me the lack of accountability (from government), as a scientist and a person in law, I would like to interrogate… There is also a lack in transparency in terms of how these regulations come about,” Amod said.
“Who advises? Why are they afraid to put out the scientific advice that was given? Are we just copying and pasting from other countries? I’d like to interrogate the science… it hasn’t been held up to scrutiny.”
The country’s Risk Adjusted Strategy allows for different municipalities and districts to be under different levels of lockdown.
“I don’t see how it would work. It’s going to be very difficult. I can see people trying to escape from one area to another… especially when people are desperate. You are going to do anything so that you can feed your children,” said Prof Susan Goldstein.
Goldstein is a medical doctor, public health specialist, and deputy director at PRICELESS SA (a unit of the South African Medical Research Council).
“I think it’s very logical thinking in a scientific way, but it’s very unhuman(sic). They haven’t really been able to predict how ordinary people will react to this. That may just be because their consultation hasn’t been engaging enough,” Goldstein said.
The new 20:00 to 05:00 curfew and the three hour exercise window (06:00 to 09:00) were also common concerns raised by the experts. “There are a number of issues that are problematic,” said Goldstein.
“There seems to be no reasons for a curfew. It is totally unclear to me why, if we didn’t have a curfew before, we have one now,” she said.“(Then) there’s the exercise issue. So, you’re allowed out for three hours, which means that everybody who is going to be exercising is going to be doing it within those three hours. Which seems contrary to not having crowds, or big numbers of people,” Goldstein said.
Amod also had questions.“The curfew itself, I don’t see the sense in it. There’s no legal or scientific justification for it. Once again, was that an arbitrary time chosen? Was there an economic reason or a scientific reason for it?” Amod asked.
“The word curfew, [also] puts a negative connotation on what the government is trying to do.”Dr Kerrin Begg, a Public Health Medicine Specialist and member of the College of Public Health Medicine Guidance task team, was similarly perplexed by the exercise regulations.
“The one that didn’t really make sense, but what I suspect has more to do with enforcement issues, is limiting exercise between 6am and 9am,” she said.
When asked if the crowds exercising could increase chances of transmission, Begg said that the risk is still relatively small if people were simply walking past one another.
“Obviously it’s worrying seeing lots of people on the (Sea Point) promenade, but I think the risk is still reasonably small, given you are actually walking past people rather than standing still at a music festival or something,” she said.
“The practical implementation of them (the regulations) from a healthcare perspective is problematic,” Amod said pointing to the example of the regulations on safety protocols for workplaces and public transport.
“I have to say from the regulations that the government has abdicated their responsibility to the population and made it totally the employer’s responsibility to monitor the staff. They’re saying, ‘if you want to stay open, you take total responsibility for monitoring the staff, monitoring people, and sending them for testing’,” Amod said.
“When we look at basic transportation issues… is it realistic to expect that people should be wearing masks while using public transport? (Many of) these people can barely afford to live above the breadline,” he noted.
“No disrespect but it is an unregulated industry, (particularly) the taxi industry Who bears the cost or the responsibility? If the taxi owners or drivers have to provide masks, make sure the vehicle is sanitised, obviously it is going to affect the price of transportation,” Amod said.
The ban on cigarette sales
The continued ban on the sale of cigarettes under level 4 has been controversial. So far the evidence regarding the impact of smoking on Covid-19 has been inconclusive.
“I think there is scope to question it (the smoking ban) from the Covid-19 perspective. Whether or not selling or restricting tobacco improves our response to the Covid epidemic, I’m not sure. We do have a sense that smoking and SARS-CoV-2 don’t go well together,” Myer said.
“Whether or not stopping people from smoking immediately actually improves someone’s chances with the virus, I’m not sure.”
Another point of concern, among many, is the move towards re-opening schools by the Department of Basic Education.According to Begg, evidence about school closures due to COVID-19 has been emerging thanks to studies in other countries.
Begg said the evidence suggests that “from an epidemic point of view and from managing the COVID-19 epidemic, that school closures don’t make a huge difference in managing the epidemic”. “Other measures related to physical distancing have a far bigger impact on controlling the epidemic than school closures do,” she said.
“The other piece of evidence that we’ve looked at is ‘are children spreaders?’(and) if school closures aren’t helping, will opening schools make it worse? And the evidence shows that is not the case,” Begg said.
Begg and her team have been investigating the feasibility of opening schools and provided guidelines for how to do so safely. “At this point, the harm of keeping schools closed, in terms of psycho-social wellbeing and physical wellbeing… The harm of staying closed, probably outweighs the harm or potential harm of returning to school,” she said.
*This article was produced by Spotlight – health journalism in the public interest. Sign up for our newsletter and stay informed.
Image credit: Getty Images
Researchers at Columbia Engineering and the University of South Carolina have developed a method that combines big data and machine learning to selectively design gas-filtering polymer membranes to reduce greenhouse gas emissions.
Their study, published today in Science Advances, is the first to apply an experimentally validated machine learning method to rapidly design and develop advanced gas separation membranes.
“Our work points to a new way of materials design and we expect it to revolutionize the field,” says the study’s PI Sanat Kumar, Bykhovsky Professor of Chemical Engineering and a pioneer in developing polymer nanocomposites with improved properties.
Plastic films or membranes are often used to separate mixtures of simple gases, like carbon dioxide (CO2), nitrogen (N2), and methane (CH4). Scientists have proposed using membrane technology to separate CO2 from other gases for natural gas purification and carbon capture, but there are potentially hundreds of thousands of plastics that can be produced with our current synthetic toolbox, all of which vary in their chemical structure. Manufacturing and testing all of these materials is an expensive and time-consuming process, and to date, only about 1,000 have been evaluated as gas separation membranes.
Kumar and his collaborators at Columbia Engineering, the University of South Carolina, and the Max Planck Society in Mainz (Germany) created a machine learning algorithm that correlates the chemical structure of the 1,000 tested polymers with their gas transport properties, to investigate what structure makes the best membrane. They then applied the algorithm to more than 10,000 known polymers to predict which would produce the best material in this context.
This procedure identified some 100 polymers that had never been tested for gas transport but were predicted to surpass the current membrane performance limits for CO2/CH4 separations.
“Rather than experimentally test all the materials that exist for a particular application, you instead test a smaller subset of materials which have the most promise. You then find the materials that combine the very best ingredients and that gives you a shot at designing a better material, just like Netflix finding you the next movie to watch,” says the study’s co-author Connor Bilchak, formerly a PhD student with Kumar and currently a post-doctoral fellow at the University of Pennsylvania.
To test the algorithm’s accuracy, a group led by Brian Benicewicz, SmartState Professor of Chemistry and Biochemistry at the University of South Carolina, synthesized two of the most promising polymer membranes predicted by this approach and found that the membranes exceeded the upper bound for CO2/CH4 separation performance.
“Their performance was very good — much better than what had been previously made,” says the study’s co-author Laura Murdock, a graduate student of Benicewicz’s. “And it was pretty easy. This methodology has significant potential for commercial use.”
Benicewicz added, “Looking beyond this one context, this method is easily extendable to other membrane materials which could profoundly affect the development of next generation batteries and technologies for water purification.”
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Materials provided by Columbia University School of Engineering and Applied Science. Original written by Holly Evarts. Note: Content may be edited for style and length.
The anti-inflammatory drug hydroxychloroquine does not significantly reduce admission to intensive care or death in patients hospitalised with pneumonia due to covid-19, finds a study from France published by The BMJ today.
A randomised clinical trial from China also published today shows that hospitalised patients with mild to moderate persistent covid-19 who received hydroxychloroquine did not clear the virus more quickly than those receiving standard care. Adverse events were higher in those who received hydroxychloroquine.
Taken together, the results do not support routine use of hydroxychloroquine for patients with covid-19.
Hydroxychloroquine can reduce inflammation, pain, and swelling, and is widely used to treat rheumatic diseases. It is also used as an anti-malarial drug. Lab tests showed promising results, but accumulating trial and observational evidence has called into question whether there are any meaningful clinical benefits for patients with covid-19.
Despite this, hydroxychloroquine has already been included in Chinese guidelines on how best to manage the disease, and the US Food and Drug Administration (FDA) issued an emergency use authorization to allow the drug to be provided to certain hospitalized patients. The FDA has since warned against use outside clinical trials or hospital settings due to the risk of heart rhythm problems.
In the first study, researchers in France assessed the effectiveness and safety of hydroxychloroquine compared with standard care in adults admitted to hospital with pneumonia due to covid-19 who needed oxygen.
Of 181 patients, 84 received hydroxychloroquine within 48 hours of admission and 97 did not (control group).
They found no meaningful differences between the groups for transfer to intensive care, death within 7 days, or developing acute respiratory distress syndrome within 10 days.
The researchers say that caution is needed in the interpretation of their results, but that their findings do not support the use of hydroxychloroquine in patients hospitalised with covid-19 pneumonia.
In the second study, researchers in China assessed the effectiveness and safety of hydroxychloroquine compared with standard care in 150 adults hospitalised with mainly mild or moderate covid-19.
Patients were randomly split into two groups. Half received hydroxychloroquine in addition to standard care and the others received standard care only (control group).
By day 28, tests revealed similar rates of covid-19 in the two groups but adverse events were more common in those who received hydroxychloroquine. Symptom alleviation and time to relief of symptoms also did not differ meaningfully between the two groups.
While further work is needed to confirm these results, the authors say that their findings do not support the use of hydroxychloroquine to treat patients with persistent mild to moderate covid-19.
Marine life off the West Coast, from Mexico up through Canada, inhabit the California Current. The cool, nutrient-rich water supports life from invisible phytoplankton to the economically important salmon, rockfish and Dungeness crab to the majestic orcas.
A new study led by the University of Washington finds that the animals’ ability to breathe in that water may be key to where and when they thrive. The study, published May 15 in Science Advances, uses recent understanding of water breathability and historical data to explain population cycles of the northern anchovy. The results for this key species could apply to other species in the current.
“If you’re worried about marine life off the west coast of North America, you’re worried about anchovies and other forage fish in the California Current. Ultimately it’s what underpins the food web,” said lead author Evan Howard, a UW postdoctoral researcher in oceanography.
The study shows that species respond to how breathable the water is — a combination of the oxygen levels in the water and the species’ oxygen needs, which are affected by water temperature. The anchovy historical data matches this pattern, and it suggests that the southern part of their range could be uninhabitable by 2100.
“Climate change isn’t just warming the oceans — it is causing oxygen to decrease, which could force fish and other ocean animals to move away from their normal range to find higher-oxygen waters,” Howard said.
Anchovy populations are known to cycle through time, but the reasons have been mysterious. Other explanations — that drew on food supplies, predator-prey interactions, competition with other species, and temperature preferences — failed to fully explain the anchovy populations cycles from the1950s to today, which have been carefully recorded.
Since the late 1940s, the California Cooperative Oceanic Fisheries Investigations, or CalCOFI, a partnership between California state and federal agencies, has monitored marine life and conditions offshore. It was established after the economically devastating crash of the sardine fishery in the 1940s with the goal of avoid another fisheries collapse and better understanding marine populations.
“They weren’t just measuring anchovies, they were measuring everything they could get their hands on,” Howard said. Because the anchovies are numerous and their populations soared after the sardine collapse, these fish provide a good record over time and space for the past half-century.
Previous research by the UW group showed that water “breathability,” the combined effects of temperature and oxygen levels, are key for marine animals’ survival. The 2015 research used models to combine the effects of warmer seawater that can hold less oxygen with marine animals’ increased metabolic needs in a warmer environment.
The new study also drew on a 2018 paper that analyzed the oxygen needs for various types of marine animals at different water temperatures. The two previous studies focused on the future, under climate change, and the distant past, for a major extinction event.
Researchers combined observations with ocean models to fill gaps in the data and showed that the breathability index changes over time and corresponds with when anchovy populations rise and fall, and when they move deeper or closer to shore.
“This study is the first one that demonstrates on a timescale of decades that a species is responding in really close alignment with this metabolic index — how breathable the ocean in its habitat has become,” said senior author Curtis Deutsch, a UW associate professor of oceanography. “It adds a new, independent line of verification that species in the ocean are arranged in accordance with how breathable their habitats are.”
The authors then looked at the extent of anchovy habitat in the future under climate change. Projected changes in the water conditions will likely make the southern part of the anchovies’ range, off the coasts of Mexico and Southern California, uninhabitable by 2100.
“We expect habitats to shift for all species that depend on oxygen for survival,” Howard said. “If we understand how these animals are responding to their environment, we can better predict how these populations will be affected as the conditions change.”
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Materials provided by University of Washington. Original written by Hannah Hickey. Note: Content may be edited for style and length.
In the Grand Canyon reach of the Colorado River, two species play an outsized role in the fate of mercury in the aquatic ecosystem, and their numbers are altered by flood events. So reports new research, published in Science Advances, that is among the first to meld ecotoxicology and ecosystem ecology to trace how mercury flows through aquatic food webs and then spreads to land.
Mercury is an environmental contaminant that occurs in ecosystems globally. In its organic form, it is a potent neurotoxin that can harm people and wildlife. Mercury accumulation in animals and how it magnifies along food chains is well studied. Less well understood are the pathways mercury takes through food webs to reach top predators, such as fish and birds, and how those pathways might change after large ecosystem disturbances, such as floods.
Emma Rosi is an aquatic ecologist at Cary Institute of Ecosystem Studies and co-lead author on the paper. She explains, “By combining data on mercury concentrations in aquatic life with well-studied food webs, we were able to reveal how mercury moves through an ecosystem. We found that flooding and an invasive species both influenced the flow of this contaminant of global concern.”
The traits of organisms living in an ecosystem — their physiology, what they eat, and what eats them — determine contaminant movement and exposure. These factors have rarely been included in models of contaminant flux and fate. “Pairing contaminant concentrations and highly detailed food webs has the potential to improve the management of contaminants in ecosystems,” Rosi notes.
To study these pathways, the research team developed mercury-based food webs for six sites spanning 225 miles of the Colorado River, extending downstream from the Glen Canyon Dam in Grand Canyon National Park. Food web sampling took place seasonally over two years. At each site, they measured algae, invertebrates, and fish to determine who was eating what — and what that meant for mercury exposure at each level of the food web.
Insects (blackflies and midges) and invasive New Zealand mudsnails were the dominant invertebrates in the river. These animals play a vital role in moving energy and contaminants from the bottom of the food web to fish predators at the top. Fish included native Bluehead Sucker, Flannelmouth Sucker, Speckled Dace, and Humpback Chub, as well as non-native species such as Common Carp, Fathead Minnow, and Rainbow Trout.
The stomach contents of invertebrates and fish were assessed to identify what they ate and in what amounts. Algae, detritus, and animals were analyzed for mercury concentrations and, combined with the diet data, the team estimated the amount of mercury that animals were consuming throughout the year.
Food web complexity varied across the study sites. Just below the Glen Canyon Dam, food webs were simple with few species and food web connections. Further downstream, food webs had higher species diversity and more connections. Across the study sites, regardless of food web complexity, relatively few species were key players in the movement of mercury.
Algae and tiny particles of detritus were the source of 80% of mercury flowing to invertebrates. In sites closest to the dam, invasive mudsnails dominated the food webs. Trout were the only fish in this part of the river, and they are unable to digest mudsnails. Mercury accumulated by the snails did not move up the food chain. Because the snails are fully aquatic, mercury cycled back into the river’s detrital food web when they died.
Blackfly larvae were the source of 56-80% of the mercury flowing to fish. Blackflies are preferred prey for fish, such as Rainbow Trout, and blackflies had higher mercury contaminations compared to other invertebrates. Blackflies that escape predation and emerge from the river as flying adults move mercury from the river to land. This can expose terrestrial predators, such as birds and bats, to mercury that started out in the river.
The amount of mercury that blackflies moved to land was dependent on the number of hungry fish in any part of the river. At some sites, fish ate nearly 100% of the blackfly larvae, leaving few left to emerge. At other sites, there were a lot more blackflies than the fish could eat. When these blackflies emerged as adults, the mercury inside them hitched a ride to terrestrial food webs along the river.
One year into sampling, the study sites were flooded as part of a planned dam release. The team was able to explore the effects of the flood on mercury movement in the food webs. At sites near the dam, the flood washed away large numbers of New Zealand mudsnails and led to a boom in blackfly populations. With the rise in blackflies, more mercury flowed to trout. Because trout gobbled up nearly all the blackflies in their larval form, very little of the mercury accumulated in these abundant insects was transported to land by the flying adults.
Rosi explains, “Changes to the animal populations in an ecosystem will impact how mercury moves through a food web. This was especially apparent at sites where flooding changed the proportion of blackflies relative to fish. Flooding dramatically altered mercury pathways in the simple tailwater food web near the dam, but not in the more complex food webs downstream.”
“Invasive species and dams are common in rivers globally, and both factors were at play in the Grand Canyon reach of the Colorado River,” Rosi says. “We found that flooding changed the species present at our study sites, and mercury flow changed with those shifts.”
“Understanding the factors that control the movement of mercury through food webs can help resource managers protect ecosystems that are susceptible to mercury pollution,” says David Walters, USGS scientist and co-lead author of the study.
Rosi concludes, “This study is exciting because it sheds light on the depth of understanding we can achieve when we merge ecological and ecotoxicological thinking. Species traits, animal populations, predator-prey interactions, and disturbance can all influence the movement of contaminants in the environment. Understanding the complex interplay of these factors can improve risk management of animal exposures in the environment.”
New research by Rutgers scientists reaffirms that modern sea-level rise is linked to human activities and not to changes in Earth’s orbit.
Surprisingly, the Earth had nearly ice-free conditions with carbon dioxide levels not much higher than today and had glacial periods in times previously believed to be ice-free over the last 66 million years, according to a paper published in the journal Science Advances.
“Our team showed that the Earth’s history of glaciation was more complex than previously thought,” said lead author Kenneth G. Miller, a Distinguished Professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick. “Although carbon dioxide levels had an important influence on ice-free periods, minor variations in the Earth’s orbit were the dominant factor in terms of ice volume and sea-level changes — until modern times.”
Sea-level rise, which has accelerated in recent decades, threatens to permanently inundate densely populated coastal cities and communities, other low-lying lands and costly infrastructure by 2100. It also poses a grave threat to many ecosystems and economies.
The paper reconstructed the history of sea levels and glaciation since the age of the dinosaurs ended. Scientists compared estimates of the global average sea level, based on deep-sea geochemistry data, with continental margin records. Continental margins, which include the relatively shallow ocean waters over a continental shelf, can extend hundreds of miles from the coast.
The study showed that periods of nearly ice-free conditions, such as 17 million to 13 million years ago, occurred when the concentration of atmospheric carbon dioxide — a key greenhouse gas driving climate change — was not much higher than today. However, glacial periods occurred when the Earth was previously thought to be ice-free, such as from 48 million to 34 million years ago.
“We demonstrate that although atmospheric carbon dioxide had an important influence on ice-free periods on Earth, ice volume and sea-level changes prior to human influences were linked primarily to minor variations in the Earth’s orbit and distance from the sun,” Miller said.
The largest sea-level decline took place during the last glacial period about 20,000 years ago, when the water level dropped by about 400 feet. That was followed by a foot per decade rise in sea level — a rapid pace that slowed from 10,000 to 2,000 years ago. Sea-level rise was then at a standstill until around 1900, when rates began rising as human activities began influencing the climate.
Future work reconstructing the history of sea-level changes before 48 million years ago is needed to determine the times when the Earth was entirely ice-free, the role of atmospheric carbon dioxide in glaciation and the cause of the natural fall in atmospheric carbon dioxide before humans.
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Materials provided by Rutgers University. Note: Content may be edited for style and length.
Moisture is the main environmental factor that triggers the degradation of the masterpiece The Scream (1910?) by Edvard Munch, according to the finding of an international team of scientists led by the CNR (Italy), using a combination of in situ non-invasive spectroscopic methods and synchrotron X-ray techniques. After exploiting the capability of the European mobile platform MOLAB in situ and non-invasively at the Munch Museum in Oslo, the researchers came to the ESRF, the European Synchrotron (Grenoble, France), the world’s brightest X-ray source, to carry out non-destructive experiments on micro-flakes originating from one of the most well-known versions of The Scream. The findings could help better preserve this masterpiece, which is seldom exhibited due to its degradation. The study is published in Science Advances.
The Scream is among the most famous paintings of the modern era. The now familiar image is interpreted as the ultimate representation of anxiety and mental anguish. There are a number of versions of The Scream, namely two paintings, two pastels, several lithographic prints and a few drawings and sketches. The two most well-known versions are the paintings that Edvard Munch created in 1893 and 1910. Each version of The Scream is unique. Munch clearly experimented to find the exact colours to represent his personal experience, mixing diverse binding media (tempera, oil and pastel) with brilliant and bold synthetic pigments to make ‘screaming colours’. Unfortunately, the extensive use of these new coloured materials poses a challenge for the long-term preservation of Munch’s artworks.
The version of the Scream (1910?) that belongs to the Munch Museum (Oslo, Norway) clearly exhibits signs of degradation in different areas where cadmium-sulfide-based pigments have been used: cadmium yellow brushstrokes have turned to an off-white colour in the sunset cloudy sky and in the neck area of the central figure. In the lake, a thickly applied opaque cadmium yellow paint is flaking. Throughout its existence, several elements have played a role in the deterioration of the masterpiece: the yellow pigments used, the environmental conditions and a theft in 2004, when the painting disappeared for two years.
Since the recovery of the painting after the theft, the masterpiece has rarely been shown to the public. Instead, it is preserved in a protected storage area in the Munch Museum, in Norway, under controlled conditions of lighting, temperature (about 18°C) and relative humidity (about 50%).
An international collaboration, led by the CNR (Italy), with the University of Perugia (Italy), the University of Antwerp (Belgium), the Bard Graduate Center in New York City (USA), the European Synchrotron (ESRF, France), the German Electron Synchrotron (DESY, Hamburg) and the Munch Museum, has studied in detail the nature of the various cadmium-sulfide pigments used by Munch, and how these have degraded over the years.
The findings provide relevant hints about the deterioration mechanism of cadmium-sulfide-based paints, with significant implication for the preventive conservation of The Scream.
“The synchrotron micro-analyses allowed us to pinpoint the main reason that made the painting decline, which is moisture. We also found that the impact of light in the paint is minor. I am very pleased that our study could contribute to preserve this famous masterpiece,” explains Letizia Monico, one of the corresponding authors of the study.
Hitting the right formula for preservation
Monico and her colleagues studied selected cadmium-sulfide-based areas of The Scream (1910?), as well as a corresponding micro-sample, using a series of non-invasive in-situ spectroscopic analyses with portable equipment of the European MOLAB platform in combination with the techniques of micro X-ray diffraction, X-ray micro fluorescence and micro X-ray absorption near edge structure spectroscopy mainly at the ESRF, the European Synchrotron, in France, the world’s most powerful synchrotron. The study of the painting was integrated with investigations of artificially aged mock-ups. The latter were prepared using a historical cadmium yellow pigment powder and a cadmium yellow oil paint tube that belonged to Munch. Both mock-ups had a similar composition to the lake in the painting. “Our goal was to compare the data from all these different pigments, in order to extrapolate the causes that can lead to deterioration,” says Monico.
The study shows that the original cadmium sulfide turns into cadmium sulfate in the presence of chloride-compounds in high-moisture conditions (relative humidity, or RH ?95%). This happens even if there is no light.
“The right formula to preserve and display the main version of The Scream on a permanent basis should include the mitigation of the degradation of the cadmium yellow pigment by minimising the exposure of the painting to excessively high moisture levels (trying to reach 45% RH or lower), while keeping the lighting at standard values foreseen for lightfast painting materials. The results of this study provide new knowledge, which may lead to practical adjustments to the Museum’s conservation strategy,” explains Irina C. A. Sandu, conservation scientist at the Munch Museum.
“Today the Munch Museum stores and exhibits Edvard Munch’s artworks at a relative humidity of about 50% and at a temperature of around 20 °C. These environmental conditions will also apply to the new Munch Museum to be opened in Spring 2020. That said, the Museum will now look into how this study may affect the current regime. Part of such a review will be to consider how other materials in the collection will respond to possible adjustments,” adds Eva Storevik Tveit, paintings conservator at the Munch Museum.
Cadmium-sulfide-based yellows are not only present in Munch’s artwork but also in the work of other artists contemporary to him, such as Henri Matisse, Vincent van Gogh and James Ensor.
“The integration of non-invasive in-situ investigations at the macro-scale level with synchrotron micro-analyses proved its worth in helping us to understand complex alteration processes. It can be profitably exploited for interrogating masterpieces that could suffer from the same weakness,” reports Costanza Miliani, coordinator of the mobile platform MOLAB (operating in Europe under the IPERION CH project) and second corresponding author of this study.
Monico and colleagues, especially Koen Janssens (University of Antwerp), have a long-standing collaboration with the ESRF, the European Synchrotron, and in particular with the scientist Marine Cotte, to investigate these pigments and the best way to preserve the original masterpieces.
“At the ESRF, ID21 is one of the very few beamlines in the world where we can perform imaging X-ray absorption and fluorescence spectroscopy analysis of the entire sample, at low energy and with sub-micrometer spatial resolution,” explains Janssens.
“EBS, the new Extremely Brilliant Source, the first-of-a-kind high-energy synchrotron, which is under commissioning at the moment at the ESRF, will further improve the capabilities of our instruments for the benefit of world heritage science. We will be able to perform microanalyses with increased sensitivity, and a greater level of detail. Considering the complexity of these artistic materials, such instrumental developments will highly benefit the analysis of our cultural heritage,” adds Cotte, ESRF scientist and CNRS researcher director.
“This kind of work shows that art and science are intrinsically linked and that science can help preserve pieces of art so that the world can continue admiring them for years to come,” concludes Miliani, coordinator of MOLAB.
