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Once-abundant sea stars imperiled by disease along West Coast
The combination of ocean warming and an infectious wasting disease has devastated populations of large sunflower sea stars once abundant along the West Coast of North America in just a few years, according to research co-led by the University of California, Davis, and Cornell University published Jan. 30 in the journal Science Advances.
“At one time plentiful in nearshore waters, the sunflower sea stars right now cannot be found off the California coast and are rare into Alaska,” said Drew Harvell, Cornell professor of ecology and evolutionary biology, a co-lead author. “Numbers of the sea stars have stayed so low in the past three years, we consider them endangered in the southern part of their range, and we don’t have data for northern Alaska.”
Since 2013, sea star wasting disease has brought about massive mortality in multiple sea star species from Mexico to Alaska. The East Coast has not been immune, as the disease has affected the shores from New Jersey to New England.
CLIMATE CHANGE A LIKELY FACTOR
Diego Montecino-Latorre, a wildlife epidemiologist with the UC Davis One Health Institute and a co-lead author, said the sunflower sea star continues to decline even in the deepest ocean and it is not recovering in the same way as the intertidal Ochre star.
“This is likely because this disease has many hosts, and other species that tolerate the pathogen better may spread it to the sunflower star,” he said.
Global warming due to a changing atmosphere is likely a major factor.
“The heat wave in the oceans — a product of increasing atmospheric temperatures — is exacerbating the sea star wasting disease,” said Harvell, a fellow at Cornell’s Atkinson Center for a Sustainable Future. “It’s a lethal disease, and when you add a higher temperature to that, it kills faster, causing a bigger impact.”
CASCADING EFFECTS
Fisheries depend on nearshore kelp forests to form a healthy environment for fish and the broader oceanic ecosystem. With the demise of sunflower sea stars, sea urchin populations in some areas have exploded, substantially reducing the kelp, Harvell said.
The sunflower sea star is large, about the size of a manhole cover, and possesses an enormous appetite. It crawls over the seafloor like a robotic vacuum cleaner, munching on everything in its path.
“In California, Washington and parts of British Columbia, sunflower sea stars keep urchins under control,” said Joseph Gaydos, senior author on the paper and director of UC Davis’ SeaDoc Society program. “Without sunflower stars, urchin populations expand and threaten kelp forests and biodiversity. This cascading effect has a really big impact.”
COUNTING STARS
Between 2006 and 2017, scientists and trained citizen scientists with Reef Environmental Education Foundation (REEF) conducted 10,956 roving-diver surveys from Southern California to Alaska. Before 2013, divers reported an abundance of sea stars, but between 2013 to 2017 the population collapsed.
Scientists from Simon Fraser University and the Hakai Institute confirmed the loss from remote Calvert Island in British Columbia. The ocean warming recorded at REEF locations corresponds to an increase in water temperature by up to 4 degrees Celsius that started in 2014.
Scientists from the National Oceanic and Atmospheric Administration surveyed sunflower sea stars in thousands of deep trawls from Mexico to the Canadian border and recorded 100 percent decline in all states in deep water down to 1,000 meters.
Stanford University also contributed to this research. The study was supported by the National Science Foundation, Natural Sciences and Engineering Research Council of Canada, NOAA and the Department of Commerce.
In mid-April, the University of California Press will release Harvell’s book, “Ocean Outbreak: Confronting the Rising Tide of Marine Disease.” It regards the oceanic epidemics impacting the food chain and proposes solutions to slow a looming global environmental disaster.
The 210-million-year-old Smok was crushing bones like a hyena
Coprolites, or fossil droppings, of the dinosaur-like archosaur Smok wawelski contain lots of chewed-up bone fragments. This led researchers at Uppsala University to conclude that this top predator was exploiting bones for salt and marrow, a behavior often linked to mammals but seldom to archosaurs.
Most predatory dinosaurs used their blade-like teeth to feed on the flesh of their prey, but they are commonly not thought to be much of bone crushers. The major exception is seen in the large tyrannosaurids, such as Tyrannosaurus rex, that roamed North America toward the end of the age of dinosaurs. The tyrannosaurids are thought to have been osteophagous (voluntarily exploiting bone) based on findings of bone-rich coprolites, bite-marked bones, and their robust teeth being commonly worn.
In a study published in Scientific Reports, researchers from Uppsala University were able to link ten large coprolites to Smok wawelski, a top predator of a Late Triassic (210 million year old) assemblage unearthed in Poland. This bipedal, 5-6 meters long animal lived some 140 million years before the tyrannosaurids of North America and had a T. rex-like appearance, although it is not fully clear whether it was a true dinosaur or a dinosaur-like precursor.
Three of the coprolites were scanned using synchrotron microtomography. This method has just recently been applied to coprolites and works somewhat like a CT scanner in a hospital, with the difference that the energy in the x-ray beams is much stronger. This makes it possible to visualize internal structures in fossils in three dimensions.
The coprolites were shown to contain up to 50 percent of bones from prey animals such as large amphibians and juvenile dicynodonts. Several crushed serrated teeth, probably belonging to the coprolite producer itself, were also found in the coprolites. This means that the teeth were repeatedly crushed against the hard food items (and involuntarily ingested) and replaced by new ones.
Further evidence for a bone-crushing behaviour can also be found in the fossils from the same bone beds in Poland. These include worn teeth and bone-rich fossil regurgitates from Smok wawelski, as well as numerous crushed or bite-marked bones.
Several of the anatomical characters related to osteophagy, such as a massive head and robust body, seem to be shared by S. wawelski and the tyrannosaurids, despite them being distantly related and living 140 million years apart. These large predators therefore seem to provide evidence of similar feeding adaptations being independently acquired at the beginning and end of the age of dinosaurs.
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Layered cocktails inspire new form of male birth control
For decades, women have shouldered most of the burden of contraception. However, long-term use of female birth control pills could increase the risk for side effects such as blood clots or breast cancer. Now, inspired by colorful layered cocktails, researchers have developed a medium-term, reversible male contraceptive. They report their results in the journal ACS Nano.
Common forms of male contraception are either short-term (condoms) or long-term (vasectomy). However, condoms can fail, and vasectomies, while effective, are not often reversible. Xiaolei Wang and colleagues wanted to devise a medium-term, reversible form of male contraception. They drew inspiration from cocktails, such as the Galaxy, that bartenders make by layering colorful liquids in a glass. If the beverage is stirred or heated, the layers combine into a uniform liquid. Wang and colleagues wondered if they could use a similar approach to inject layers of materials to block the vas deferens, the duct that conveys sperm from the testicle to the urethra. Applying heat would cause the layers to mix, breaking them down and “unplugging the pipeline.”
The team tested their approach in male rats. They sequentially injected four layers of materials into the vas deferens: a hydrogel that forms a physical barrier to sperm; gold nanoparticles, which heat up when irradiated with near-infrared light; ethylenediaminetetraacetic acid (EDTA), a chemical that breaks down the hydrogel and also kills sperm; and finally, another layer of gold nanoparticles. The injected materials kept the rats from impregnating females for more than 2 months. However, when the researchers shone a near-infrared lamp on the rats for a few minutes, the layers mixed and dissolved, allowing the animals to produce offspring. The researchers say that while this pilot experiment is promising, more research is needed to verify the safety of the materials.
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Health24.com | A hormone in your blood could predict unhealthy ageing
A hormone found in the blood that’s commonly linked to heart disease also might signal when someone is more likely to grow weaker or lose their ability to balance before they’re 70.
People in their early 60s with higher-than-normal levels of brain natriuretic peptide, or BNP, walked slower and were less able to raise themselves from a chair and balance on one leg up to nine years later, according to a study by British researchers published Tuesday in the American Heart Association’s journal Circulation.
While high levels of the peptide are associated with greater risk for heart attacks and other diseases, the new study indicates it could be more than just a warning sign of heart disease.
“We were surprised that BNP turned out to be the best predictor of our simple measures of ageing,” said Yoav Ben-Shlomo, who helped author the study for the Medical Research Council Unit for Lifelong Health and Aging at University College London.
BNP is primarily produced in the heart’s left ventricle, the heart’s main pumping chamber. It’s produced when the heart is working too hard to pump blood. It is possible that if a blood test shows someone with higher-than-normal levels in their 30s or 40s, Ben-Shlomo said, they might be able to lessen their risk of ageing more rapidly with more exercise and a healthy diet now.
The flamingo test
The study evaluated 1 736 British men and women who have been tracked since their births in 1946 and who took physical performance tests at ages 60 to 65. Researchers in 2014 and 2015 updated those measurements, when the participants were in their late 60s.
“Our measures include how strong your grip is, how fast you walk a specific distance, how long it takes you to raise from a chair 10 times and how long you are able to stand on one leg, which is called the flamingo test,” Ben-Shlomo said.
If the results are confirmed in other independent studies, he said, it could mean future generations can better understand when they are younger how to lower their risk for a rapid loss of physical ability as they age. These blood markers also could be used in trials that are trying to slow down ageing.
Increasing physical activity in mid-life might stave off a later physical decline for people with high BNP levels for similar reasons that people with more education are less likely to get dementia, Ben-Shlomo said.
“The theory is if you can reach a higher peak in young adulthood, you have more room to decline later in life – as we all do,” he said.
Benefits of physical activity
The new research reinforces earlier findings that exercise can help overcome a genetic history that makes someone more likely to suffer maladies like heart disease, said Dr Erik Ingelsson, a professor of medicine at Stanford University who is not associated with the latest study.
“It’s a nice, well-performed study and a good opportunity to re-emphasise the benefits of physical activity,” Ingelsson said.
The new study accounted for common reasons people lose strength and balance late in life, including heart disease, kidney disease and diabetes. High levels of the peptides were more associated with lost balance and strength among study participants than health problems such as high blood pressure, high cholesterol and even smoking.
About 14% of US adults smoked in 2017, down from more than 42% in 1965, the year after the US surgeon general linked the habit to lung cancer and heart disease. Similarly, if blood markers could show a risk of faster-than-normal physical decline as people age, it might be the extra push some people need to change their behaviour and reduce future health risks, Ben-Shlomo said.
“It’s a new year and people make resolutions to go to the gym and to go on diets,” he said. “This (information) might give some people more incentive to stick to it.”
Health24.com | Plant-based diets good for the planet, and for you
A low-carbon diet – one high in vegetables and grains – is good for both your health and the planet, researchers say.
Food production is a major contributor to climate change, so researchers decided to examine the carbon footprint of more than 16 000 Americans’ diets.
Lower-carbon diets healthier overall
“People whose diets had a lower carbon footprint were eating less red meat and dairy – which contribute to a larger share of greenhouse gas emissions and are high in saturated fat – and consuming more healthful foods like poultry, whole grains and plant-based proteins,” said study author Diego Rose. He’s a professor of nutrition and food security at Tulane University, in New Orleans.
The highest-carbon diets accounted for five times the emissions of the lowest-carbon diets. The high-carbon diets had greater amounts of meat, dairy and solid fats, and higher concentrations of total proteins and animal protein foods, the investigators said.
But even though lower-carbon diets were healthier overall, they contained some unhealthy items such as sugars and refined grains, and had lower amounts of important nutrients, such as iron, calcium and vitamin D, likely due to lower consumption of meat and dairy.
The study was published in the American Journal of Clinical Nutrition.
Total elimination not required
On 16 January, an international panel of experts issued a report in The Lancet that showed the average person’s daily diet will need to change drastically during the next three decades to make sure everyone is fed without depleting the planet.
And a study released earlier this year by Rose’s team found that 20% of Americans accounted for nearly half of the nation’s diet-related greenhouse gas emissions.
The goal of the research is to help the public and policymakers understand that improving diet quality can also help the environment, according to Rose.
“We can have both. We can have healthier diets and reduce our food-related emissions,” he said in a Tulane news release.
“And it doesn’t require the extreme of eliminating foods entirely. For example, if we reduce the amount of red meat in our diets, and replace it with other protein foods such as chicken, eggs or beans, we could reduce our carbon footprint and improve our health at the same time,” Rose explained.
Image credit: iStock
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Health24.com | Dealing with anaemia at school
Anaemia is a haematological disease that affects nearly a quarter of the world’s population.
Anaemia occurs when the body doesn’t have enough iron to produce sufficient numbers of red blood cells. Red blood cells are needed to store and transport oxygen to the body’s organs. When there aren’t enough red blood cells, these organs do not receive sufficient oxygen. This can lead to significant organ and tissue damage.
According to a study on the global prevalence of anaemia, pregnant women and children are most affected by the condition.
Children, as a result of various bodily changes and growth spurts, are highly susceptible to the condition. Menstruating females are also at risk for anaemia due to the heavy blood loss experienced during their periods.
School ground
Children spend up to eight hours at school. This includes class time, lunch breaks, exams, physical education, and sport and other extramural activities. School days are especially demanding for kids with anaemia, and can have a negative impact on their academic career and sports performance.
Common symptoms of anaemia include fatigue, shortness of breath, lethargy, a pale complexion and heart palpitations. Experiencing these symptoms at school can be scary, especially if kids are not aware of their condition. If you suspect that your child may be suffering from anaemia, you should take them to your local GP as soon as possible.
Adding iron
If your child has anaemia, here are some steps you can take to ensure they’re getting enough iron.
Copper and cast iron pots
Try cooking your family meals in copper or cast iron pots. Copper pots help to increase iron absorption, and cast iron pots can add a large amount of iron to your diet.
Iron-rich foods
There are many foods you can prepare for your child that are a great source of iron. These include beans, lentils, spinach, red meat, seafood, whole grain breads and dried fruits.
Iron supplements
Various pharmacies and health and wellness stores sell good iron supplements your kids can take orally. Many of these supplements are made more palatable to children by various flavours.
Image credit: iStock
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NHS trust chief in no-deal Brexit medicine warning
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Earth’s continental nurseries discovered beneath mountains
In his free time last summer, Rice University geoscientist Ming Tang made a habit of comparing the niobium content in various rocks in a global minerals database. What he found was worth skipping a few nights out with friends.
In a paper published this month by Nature Communications, Tang, Rice petrologist Cin-Ty Lee and colleagues offered an answer to one of Earth science’s fundamental questions: Where do continents form?
“If our conclusions are correct, every piece of land that we are now sitting on got its start someplace like the Andes or Tibet, with very mountainous surfaces,” said Tang, lead author of the study and a postdoctoral research associate in Rice’s Department of Earth, Environmental and Planetary Sciences (EEPS). “Today, most places are flat because that is the stable stage of the continental crust. But what we found was that when the crust formed, it had to start out with mountain-building processes.”
The connection between niobium, one of Earth’s rarest elements, and continent formation is a story that plays out over billions of years at scales as small as molecules and as large as mountain ranges. The leading players are niobium and tantalum, rare metals so alike that geologists often think of them as twins.
“They have very similar chemical properties and behave almost identically in most geological processes,” Tang said. “If you measure tantalum and niobium, you find that their ratio is nearly constant in Earth’s mantle. That means that when you find more niobium in a rock, you will find more tantalum, and when you find less niobium, you will find less tantalum.”
The mantle is Earth’s thickest layer, spanning about 1,800 miles between the planet’s core and its thin outer crust. Earth scientists believe that little, if anything, moves between the mantle and core, but the mantle and everything above it — seafloor, oceans, continents and atmosphere — are connected, and many of the atoms on Earth’s surface today, including the atoms in humans and other living things, have cycled through the mantle one or more times in Earth’s 4.6 billion years.
The rocks in continents are an exception. Geologists have found some that are up to 4 billion years old, which means they were formed near the surface and stayed on the surface, without being recycled into the mantle. That’s due in part to the nature of continental crust, which is far less dense than the basaltic rocks beneath Earth’s oceans. Lee, professor and EEPS department chair, said it’s no coincidence that Earth is the only rocky planet known to have both continents and life.
“Every day we live on continents, and we take most of our resources from continents,” Lee said. “We have oxygen in the air to breath and just the right temperature to support complex life. These things are so common that we take them for granted, but Earth didn’t start off with these conditions. They developed later in Earth’s history. And the emergence of continents is one of the things that shaped our planet and made it more livable.”
Scientists still lack details about how continents got their start and how they grew to cover 30 percent of Earth’s surface, but one big clue relates to niobium and tantalum, the geochemical twins.
“On average, the rocks in continental crust have about 20 percent less niobium than they should compared to the rock we see everywhere else,” Tang said. “We believe this missing niobium is tied to the mystery of continents. By solving or finding the missing the niobium, we can get important information about how continents form.”
Geologists have known about the imbalance for decades. And it certainly suggests that the geochemical processes that produce continental crust also remove niobium. But where was the missing niobium?
That nagging question prompted Tang to spend his free time perusing records in the Max Planck Institute’s GEOROC database, a comprehensive global collection of published analyses of volcanic rocks.
Based on those searches and months of follow-up tests, Tang, Lee and colleagues offer the first physical evidence that “arclogites” (pronounced ARC-loh-jyts) are responsible for the missing niobium. Arclogites are cumulates, the leftover dross that accumulates near the base of continental arcs. On rare occasions, chunks of these cumulates erupt onto the surface from volcanos.
The Rice group first sent arclogite samples that Lee had collected in Arizona to their collaborator, Kang Chen, a research fellow based at the China University of Geosciences in Wuhan. Chen spent a month getting precise readings of the relative amounts of niobium and tantalum in the samples. The rocks were created when the High Sierras were an active continental arc, like the Andes today.
Chen’s tests confirmed high niobium-tantalum ratios, but to better understand the mechanism by which this signature was developed, Tang and Lee used high precision laser ablation and “inductively coupled plasma mass spectrometry” in Lee’s laboratory at Rice to reveal the mineral rutile was responsible.
“Rutile is the mineral that hosts the niobium,” he said. “It’s a naturally occurring form of titanium oxide, and it is what actually ‘sees’ the difference between niobium and tantalum and captures one more than the other.”
But that happens only under specific conditions. For example, Tang said that at temperatures above 1,000 degrees Celsius, rutile traps normal ratios of tantalum and niobium. It only begins to prefer niobium when temperatures drop below 1,000 degrees Celsius. Tang said the only known place with that set of conditions is deep beneath continental arcs, like the Andes today or the High Sierras about 80 million years ago.
“The reason you need high pressure is that titanium oxide is relatively rare,” he said. “You need very high pressure to force it to crystalize and fall out of the magma.”
In an earlier arclogite study published in Science Advances last May, Tang and Lee discovered a subtle chemical signature that can explain why continental crust is iron-depleted. Lee said that finding and the discovery about rutile and niobium illustrate the central importance of continental arcs in Earth history.
“Continental arcs are like a magic system that links everything together, from climate and oxygen concentrations in the atmosphere to ore deposits,” Lee said. “They’re a sink for carbon dioxide after they die. They can drive greenhouse or icehouse, and they are the building blocks of continents.”
Antireflection coating makes plastic invisible
Antireflection (AR) coatings on plastics have a multitude of practical applications, including glare reduction on eyeglasses, computer monitors and the display on your smart-phone when outdoors. Now, researchers at Penn State have developed an AR coating that improves on existing coatings to the extent that it can make transparent plastics, such as Plexiglas, virtually invisible.
“This discovery came about as we were trying to make higher-efficiency solar panels,” said Chris Giebink, associate professor of electrical engineering, Penn State. “Our approach involved concentrating light onto small, high-efficiency solar cells using plastic lenses, and we needed to minimize their reflection loss.”
They needed an antireflection coating that worked well over the entire solar spectrum and at multiple angles as the sun crossed the sky. They also needed a coating that could stand up to weather over long periods of time outdoors.
“We would have liked to find an off-the-shelf solution, but there wasn’t one that met our performance requirements,” he said. “So, we started looking for our own solution.”
That was a tall order. Although it is comparatively easy to make a coating that will eliminate reflection at a particular wavelength or in a particular direction, one that could fit all their criteria did not exist. For instance, eyeglass AR coatings are targeted to the narrow visible portion of the spectrum. But the solar spectrum is about five times as broad as the visible spectrum, so such a coating would not perform well for a concentrating solar cell system.
Reflections occur when light travels from one medium, such as air, into a second medium, in this case plastic. If the difference in their refractive index, which specifies how fast light travels in a particular material, is large — air has a refractive index of 1 and plastic 1.5 — then there will be a lot of reflection. The lowest index for a natural coating material such as magnesium fluoride or Teflon is about 1.3. The refractive index can be graded — slowly varied — between 1.3 and 1.5 by blending different materials, but the gap between 1.3 and 1 remains.
In a paper recently posted online ahead of print in the journal Nano Letters, Giebink and coauthors describe a new process to bridge the gap between Teflon and air. They used a sacrificial molecule to create nanoscale pores in evaporated Teflon, thereby creating a graded index Teflon-air film that fools light into seeing a smooth transition from 1 to 1.5, eliminating essentially all reflections.
“The interesting thing about Teflon, which is a polymer, is when you heat it up in a crucible, the large polymer chains cleave into smaller fragments that are small enough to volatize and send up a vapor flux. When these land on a substrate they can repolymerize and form Teflon,” Giebink said.
When the sacrificial molecules are added to the flux, the Teflon will reform around the molecules. Dissolving the sacrificial molecules out leaves a nanoporous film that can be graded by adding more pores.
“We’ve been interacting with a number of companies that are looking for improved antireflection coatings for plastic, and some of the applications have been surprising,” he said. “They range from eliminating glare from the plastic domes that protect security cameras to eliminating stray reflections inside virtual/augmented -reality headsets.”
One unexpected application is in high altitude UAVs, or unmanned aerial vehicles. These are planes with giant wingspans that are coated with solar cells. Used primarily for reconnaissance, these planes rely on sunlight to stay in near perpetual flight and so a lot of the light they receive is at a glancing angle where reflections are highest. One of the companies that makes these solar cells is exploring the AR coating to see if it can improve the amount of light harvested by a UAV.
Because the technology is compatible with current manufacturing techniques, Giebink believes the coating technology is scalable and widely applicable. At this point, his test samples have stood up to central Pennsylvania weather for two years, with little change in properties. In addition, the coating is also antifogging.
“The coating adheres well to different types of plastics, but not glass,” he said. “So, it’s not going to be useful for your typical rooftop solar panel with a protective glass cover. But if concentrating photovoltaics make a comeback, a critical part of those is the plastic Fresnel lenses, and we could make a difference there.”
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