Global study of extreme drought impacts on grasslands and shrublands

A global study organized and led by Colorado State University scientists shows that the effects of extreme drought -- which is expected to increase in frequency with climate change -- has been greatly underestimated for grasslands and shrublands.

The findings -- published in Proceedings of the National Academy of Sciences -- quantify the impact of extreme short-term drought on grassland and shrubland ecosystems across six continents with a level of detail that was not previously possible.

It is the first time an experiment this extensive has been undertaken to generate a baseline understanding of the potential losses of plant productivity in these vital ecosystems.

Melinda Smith, a professor in the Department of Biology at CSU, led the study and is the first author on the paper.

She said the observed reduction in a key carbon cycle process after a single 1-in-100-year drought event greatly exceeds previously reported losses for grasslands and shrublands.

"We were able to determine that the loss of aboveground plant growth -- a key measure of ecosystem function -- was 60% greater when short-term drought was extreme compared to the less severe droughts that have been more commonly experienced historically," she said.

"Past studies suffered from methodological differences when estimating the impacts of extreme drought in natural ecosystems, but our standardized, distributed approach here addressed that problem."

Smith added that the project also showcases the variability in drought response across grassland and shrubland ecosystems -- offering both a review of the global impacts of climate change as well as a glimpse into which areas will be most stressed or most resilient in the coming years.

Gathering global extreme drought data on grassland and shrubland ecosystems Known as the International Drought Experiment, the newly published research originally dates back to 2013 as part of the National Science Foundation's Drought-Net Research Coordination Network.

Altogether, there are more than 170 authors representing institutions from around the world cited in the new PNAS study, which was completed over the last four years.

To gather their data, researchers built rainfall manipulation structures to experimentally reduce the amount of naturally occurring precipitation available to ecosystems for at least a full growing season.

About half of the participating sites imposed extreme drought conditions with these structures, while the rest imposed less severe drought for comparison.

As Earth's climate continues to change, short-term droughts that are statistically extreme in intensity will become more common, with what were once considered 1-in-100-year droughts now potentially happening every two to five years, said Smith.

But because of the historic rarity of extreme droughts researchers had been unable to estimate the actual magnitude of their ecological consequences.

Smith said grasslands and shrublands were perfect test areas to fill that research gap because they are easier to manipulate for study than other systems, such as forests.

They also store more than 30% of the global stock of carbon and support key industries such as livestock production.

"They are key ecosystems that are scalable to the globe, which makes them highly relevant for this kind of work," said Smith, who also serves as chair of the Faculty Council on campus.

"Grasslands and shrublands cover between 30% and 40% of the globe and frequently see deficits in precipitation. That means they are more vulnerable to climate change."

Findings from the sites also provide insight into how specific climates, soil and vegetation types broadly influence drought response.

While the work shows that drier and less diverse sites like those in Colorado are likely to be the most vulnerable to extremes, Smith said the severity of the drought was the most consistent and important factor in determining an ecosystem's response.

"Our data suggests greater losses in drier sites, but if you are getting to the extremes -- which is what is being forecasted -- we can generally expect substantial losses no matter where you are in the world," she said.

"We also found that even moderate losses from less severe droughts would still likely result in large impacts to the populations that rely on these systems. And then there is a combined loss of function across the globe to consider as well."

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Bottled water can contain hundreds of thousands of previously uncounted tiny plastic bits

In recent years, there has been rising concern that tiny particles known as microplastics are showing up basically everywhere on Earth, from polar ice to soil, drinking water and food. Formed when plastics break down into progressively smaller bits, these particles are being consumed by humans and other creatures, with unknown potential health and ecosystem effects. One big focus of research: bottled water, which has been shown to contain tens of thousands of identifiable fragments in each container.

Now, using newly refined technology, researchers have entered a whole new plastic world: the poorly known realm of nanoplastics, the spawn of microplastics that have broken down even further. For the first time, they counted and identified these minute particles in bottled water. They found that on average, a liter contained some 240,000 detectable plastic fragments -- 10 to 100 times greater than previous estimates, which were based mainly on larger sizes.

The study was just published in the journal Proceedings of the National Academy of Sciences.

Nanoplastics are so tiny that, unlike microplastics, they can pass through intestines and lungs directly into the bloodstream and travel from there to organs including the heart and brain. They can invade individual cells, and cross through the placenta to the bodies of unborn babies. Medical scientists are racing to study the possible effects on a wide variety of biological systems.

"Previously this was just a dark area, uncharted. Toxicity studies were just guessing what's in there," said study coauthor Beizhan Yan, an environmental chemist at Columbia University's Lamont-Doherty Earth Observatory. "This opens a window where we can look into a world that was not exposed to us before."

Worldwide plastic production is approaching 400 million metric tons a year. More than 30 million tons are dumped yearly in water or on land, and many products made with plastics including synthetic textiles shed particles while still in use. Unlike natural organic matter, most plastics do not break down into relatively benign substances; they simply divide and redivide into smaller and smaller particles of the same chemical composition. Beyond single molecules, there is no theoretical limit to how small they can get.

Microplastics are defined as fragments ranging from 5 millimeters (less than a quarter inch) down to 1 micrometer, which is 1 millionth of a meter, or 1/25,000th of an inch. (A human hair is about 70 micrometers across.) Nanoplastics, which are particles below 1 micrometer, are measured in billionths of a meter.

Plastics in bottled water became a public issue largely after a 2018 study detected an average of 325 particles per liter; later studies multiplied that number many times over. Scientists suspected there were even more than they had yet counted, but good estimates stopped at sizes below 1 micrometer -- the boundary of the nano world.

"People developed methods to see nano particles, but they didn't know what they were looking at," said the new study's lead author, Naixin Qian, a Columbia graduate student in chemistry. She noted that previous studies could provide bulk estimates of nano mass, but for the most part could not count individual particles, nor identify which were plastics or something else.

The new study uses a technique called stimulated Raman scattering microscopy, which was co-invented by study coauthor Wei Min, a Columbia biophysicist. This involves probing samples with two simultaneous lasers that are tuned to make specific molecules resonate. Targeting seven common plastics, the researchers created a data-driven algorithm to interpret the results. "It is one thing to detect, but another to know what you are detecting," said Min.

The researchers tested three popular brands of bottled water sold in the United States (they declined to name which ones), analyzing plastic particles down to just 100 nanometers in size. They spotted 110,000 to 370,000 particles in each liter, 90% of which were nanoplastics; the rest were microplastics. They also determined which of the seven specific plastics they were, and charted their shapes -- qualities that could be valuable in biomedical research.

One common one was polyethylene terephthalate or PET. This was not surprising, since that is what many water bottles are made of. (It is also used for bottled sodas, sports drinks and products such as ketchup and mayonnaise.) It probably gets into the water as bits slough off when the bottle is squeezed or gets exposed to heat. One recent study suggests that many particles enter the water when you repeatedly open or close the cap, and tiny bits abrade.

However, PET was outnumbered by polyamide, a type of nylon. Ironically, said Beizhan Yan, that probably comes from plastic filters used to supposedly purify the water before it is bottled. Other common plastics the researchers found: polystyrene, polyvinyl chloride and polymethyl methacrylate, all used in various industrial processes.

A somewhat disturbing thought: the seven plastic types the researchers searched for accounted for only about 10% of all the nanoparticles they found in samples; they have no idea what the rest are. If they are all nanoplastics, that means they could number in the tens of millions per liter. But they could be almost anything, "indicating the complicated particle composition inside the seemingly simple water sample," the authors write. "The common existence of natural organic matter certainly requires prudent distinguishment."

The researchers are now reaching beyond bottled water. "There is a huge world of nanoplastics to be studied," said Min. He noted that by mass, nanoplastics comprise far less than microplastics, but "it's not size that matters. It's the numbers, because the smaller things are, the more easily they can get inside us."

Among other things, the team plans to look at tap water, which also has been shown to contain microplastics, though far less than bottled water. Beizhan Yan is running a project to study microplastics and nanoplastics that end up in wastewater when people do laundry -- by his count so far, millions per 10-pound load, coming off synthetic materials that comprise many items. (He and colleagues are designing filters to reduce the pollution from commercial and residential washing machines.) The team will soon identify particles in snow that British collaborators trekking by foot across western Antarctica are currently collecting. They also are collaborating with environmental health experts to measure nanoplastics in various human tissues and examine their developmental and neurologic effects.

"It is not totally unexpected to find so much of this stuff," said Qian. "The idea is that the smaller things get, the more of them there are."

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Meteorite analysis shows Earth's building blocks contained water

When our Sun was a young star, 4.56 billion years ago, what is now our solar system was just a disk of rocky dust and gas. Over tens of millions of years, tiny pebbles of dust coalesced, like a snowball rolling larger and larger, to become kilometer-sized "planetesimals" -- the building blocks of Earth and the other inner planets.

Researchers have long tried to understand the ancient environments in which these planetesimals formed.

For example, water is now abundant on Earth, but has it always been?

In other words, did the planetesimals that accreted into our planet contain water?

Now, a new study combines meteorite data with thermodynamic modeling and determines that the earliest inner solar system planetesimals must have formed in the presence of water, challenging current astrophysical models of the early solar system.

The research was conducted in the laboratory of Paul Asimow (MS '93, PhD '97), Eleanor and John R. McMillan Professor of Geology and Geochemistry and appears in the journal Nature Astronomy on January 9.

Researchers have samples of the earliest years of the solar system in the form of iron meteorites.

These meteorites are the remnants of the metallic cores of the earliest planetesimals in our solar system that avoided accretion into a forming planet and instead orbited around the solar system before ultimately falling onto our planet.

The chemical compositions of meteorites such as these can reveal information about the environments in which they formed and answer questions such as whether the building blocks of Earth formed far from our Sun, where cooler temperatures allowed the existence of water ice, or if they instead formed closer to the Sun, where the heat would have evaporated any water and resulted in dry planetesimals.

If the latter is correct, then Earth would have formed dry and gained its water through some other method later in its evolution.

Though the meteorites themselves do not contain any water, scientists can infer its long-lost presence by examining its impact on other chemical elements.

Water is composed of two hydrogen atoms and one oxygen atom.

In the presence of other elements, water will often transfer its oxygen atom away in a process called oxidation.

For example, iron metal (Fe) reacts with water (H2O) to form iron oxide (FeO). A sufficient excess of water can drive the process further, producing Fe2O3 and FeO(OH), the ingredients of rust.

Mars, for example, is covered in rusty iron oxide, providing strong evidence that the Red Planet once had water.

Damanveer Grewal, a former Caltech postdoctoral scholar and first author of the new study, specializes in using chemical signatures from iron meteorites to gather information about the early solar system.

Though any iron oxide from the earliest planetesimals is now long gone, the team could determine how much iron would have been oxidized by examining the metallic nickel, cobalt, and iron contents of these meteorites.

These three elements should be present in roughly equal ratios relative to other primitive materials, so if any iron was "missing," this would imply that the iron had been oxidized.

"Iron meteorites have been somewhat neglected by the planet-formation community, but they constitute rich stores of information about the earliest period of solar system history, once you work out how to read the signals," says Asimow.

"The difference between what we measured in the inner solar system meteorites and what we expected implies an oxygen activity about 10,000 times higher."

The researchers found that those iron meteorites thought to be derived from the inner solar system had about the same amount of missing iron metal as meteorites derived from the outer solar system.

For this to be the case, the planetesimals from both groups of meteorites must have formed in a part of the solar system where water was present, implying that the building blocks of planets accreted water right from the beginning.

The signatures of water in these planetesimals challenge many of the current astrophysical models of the solar system.

If planetesimals formed at Earth's current orbital position, water would have existed only if the inner solar system was much cooler than models currently predict.

Alternatively, they may have formed further out, where it was cooler, and migrated in.

"If water was present in the early building blocks of our planet, other important elements like carbon and nitrogen were likely present as well," says Grewal.

"The ingredients for life may have been present in the seeds of rocky planets right from the start."

"However, the method only detects water that was used up in oxidizing iron," adds Asimow.

"It is not sensitive to excess water that might go on to form the ocean. So, the conclusions of this study are consistent with Earth accretion models that call for late addition of even more water-rich material."

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Three iron rings in a planet-forming disk

The origin of Earth and the Solar System inspires scientists and the public alike. By studying the present state of our home planet and other objects in the Solar System, researchers have developed a detailed picture of the conditions when they evolved from a disk made of dust and gas surrounding the infant sun some 4.5 billion years ago.

Three rings hinting at two planets

With the breathtaking progress made in star and planet formation research aiming at far-away celestial objects, we can now investigate the conditions in environments around young stars and compare them to the ones derived for the early Solar System. Using the European Southern Observatory's (ESO) Very Large Telescope Interferometer (VLTI), an international team of researchers led by József Varga from the Konkoly Observatory in Budapest, Hungary, did just that. They observed the planet-forming disk of the young star HD 144432, approximately 500 light-years away.

"When studying the dust distribution in the disk's innermost region, we detected for the first time a complex structure in which dust piles up in three concentric rings in such an environment," says Roy van Boekel. He is a scientist at the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany and a co-author of the underlying research article to appear in the journal Astronomy & Astrophysics. "That region corresponds to the zone where the rocky planets formed in the Solar System," van Boekel adds. Compared to the Solar System, the first ring around HD 144432 lies within Mercury's orbit, and the second is close to Mars's trajectory. Moreover, the third ring roughly corresponds to Jupiter's orbit.

Up to now, astronomers have found such configurations predominantly on larger scales corresponding to the realms beyond where Saturn circles the Sun. Ring systems in the disks around young stars generally point to planets forming within the gaps as they accumulate dust and gas on their way. However, HD 144432 is the first example of such a complex ring system so close to its host star. It occurs in a zone rich in dust, the building block of rocky planets like Earth. Assuming the rings indicate the presence of two planets forming within the gaps, the astronomers estimated their masses to resemble roughly that of Jupiter.

Conditions may be similar to the early Solar System

The astronomers determined the dust composition across the disk up to a separation from the central star that corresponds to the distance of Jupiter from the Sun. What they found is very familiar to scientists studying Earth and the rocky planets in the Solar System: various silicates (metal-silicon-oxygen compounds) and other minerals present in Earth's crust and mantle, and possibly metallic iron as is present in Mercury's and Earth's cores. If confirmed, this study would be the first to have discovered iron in a planet-forming disk.

"Astronomers have thus far explained the observations of dusty disks with a mixture of carbon and silicate dust, materials that we see almost everywhere in the Universe," van Boekel explains. However, from a chemical perspective an iron and silicate mixture is more plausible for the hot, inner disk regions. And indeed, the chemical model that Varga, the main author of the underlying research article, applied to the data yields better-fitting results when introducing iron instead of carbon.

Furthermore, the dust observed in the HD 144432 disk can be as hot as 1800 Kelvin (approx. 1500 degrees Celsius) at the inner edge and as moderate as 300 Kelvin (approx. 25 degrees Celsius) farther out. Minerals and iron melt and recondense, often as crystals, in the hot regions near the star. In turn, carbon grains would not survive the heat and instead be present as carbon monoxide or carbon dioxide gas. However, carbon may still be a significant constituent of the solid particles in the cold outer disk, which the observations carried out for this study cannot trace.

Iron-rich and carbon-poor dust would also fit nicely with the conditions in the Solar System. Mercury and Earth are iron-rich planets, while the Earth contains relatively little carbon. "We think that the HD 144432 disk may be very similar to the early Solar System that provided lots of iron to the rocky planets we know today," says van Boekel. "Our study may pose as another example showing that the composition of our Solar System may be quite typical."

Interferometry resolves tiny details

Retrieving the results was only possible with exceptionally high-resolution observations, as provided by the VLTI. By combining the four VLT 8.2-metre telescopes at ESO's Paranal Observatory, they can resolve details as if astronomers would employ a telescope with a primary mirror of 200 metres in diameter. Varga, van Boekel and their collaborators obtained data using three instruments to achieve a broad wavelength coverage ranging from 1.6 to 13 micrometres, representing infrared light.

MPIA provided vital technological elements to two devices, GRAVITY and the Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE). One of MATISSE's primary purposes is to investigate the rocky planet-forming zones of disks around young stars. "By looking at the inner regions of protoplanetary disks around stars, we aim to explore the origin of the various minerals contained in the disk -- minerals that later will form the solid components of planets like the Earth," says Thomas Henning, MPIA director and co-PI of the MATISSE instrument.

However, producing images with an interferometer like the ones we are used to obtaining from single telescopes is not straightforward and very time-consuming. A more efficient use of precious observing time to decipher the object structure is to compare the sparse data to models of potential target configurations. In the case of the HD 144432 disk, a three-ringed structure represents the data best.

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Evolution is not as random as previously thought

A groundbreaking study has found that evolution is not as unpredictable as previously thought, which could allow scientists to explore which genes could be useful to tackle real-world issues such as antibiotic resistance, disease and climate change.

The study, which is published in the Proceedings of the National Academy of Sciences (PNAS), challenges the long-standing belief about the unpredictability of evolution, and has found that the evolutionary trajectory of a genome may be influenced by its evolutionary history, rather than determined by numerous factors and historical accidents.

The study was led by Professor James McInerney and Dr. Alan Beavan from the School of Life Sciences at the University of Nottingham, and Dr. Maria Rosa Domingo-Sananes from Nottingham Trent University.

"The implications of this research are nothing short of revolutionary," said Professor McInerney, the lead author of the study.

"By demonstrating that evolution is not as random as we once thought, we've opened the door to an array of possibilities in synthetic biology, medicine, and environmental science."

The team carried out an analysis of the pangenome -- the complete set of genes within a given species, to answer a critical question of whether evolution is predictable or whether the evolutionary paths of genomes are dependent on their history and so not predictable today.

Using a machine learning approach known as Random Forest, along with a dataset of 2,500 complete genomes from a single bacterial species, the team carried out several hundred thousand hours of computer processing to address the question.

After feeding the data into their high-performance computer, the team first made "gene families" from each of the gene of each genome.

"In this way, we could compare like-with-like across the genomes," said Dr. Domingo-Sananes.

Once the families had been identified, the team analysed the pattern of how these families were present in some genomes and absent in others.

"We found that some gene families never turned up in a genome when a particular other gene family was already there, and on other occasions, some genes were very much dependent on a different gene family being present."

In effect, the researchers discovered an invisible ecosystem where genes can cooperate or can be in conflict with one another.

"These interactions between genes make aspects of evolution somewhat predictable and furthermore, we now have a tool that allows us to make those predictions," adds Dr. Domingo-Sananes.

Dr Beavan said: "From this work, we can begin to explore which genes "support" an antibiotic resistance gene, for example. Therefore, if we are trying to eliminate antibiotic resistance, we can target not just the focal gene, but we can also target its supporting genes.

"We can use this approach to synthesise new kinds of genetic constructs that could be used to develop new drugs or vaccines. Knowing what we now know has opened the door to a whole host of other discoveries."

Read more at Science Daily

Building on CO2

The construction industry as a CO2 sink? Researchers at Empa's Concrete & Asphalt lab are working on this. By incorporating biochar into concrete, they are exploring the potential of CO2-neutral or even CO2-negative concrete. For optimal applicability, they process the biochar into pellets and use them to replace conventional aggregates.

To achieve the goal of a climate-neutral Switzerland by 2050, strategies and processes with a negative CO2 balance are necessary.

These so-called negative emission technologies (NET) are intended to counterbalane the remaining "hard-to-avoid" emissions in 2050 and should help ensure that we eventually achieve net zero.

As one of the main emitters, the construction sector has a particular obligation.

Around eight percent of global greenhouse gas emissions are caused by cement production.

At the same time, initial efforts are emerging to use the construction sector, with its massive consumption of resources, as a possible carbon sink.

What sounds paradoxical will succeed if we start "building with CO2" -- or rather, using carbon to produce building materials and thus removing it from the atmosphere in the long term.

For such visions to become reality, a great deal of research is needed -- such as is currently being done at Empa's Concrete & Asphalt lab.

A team led by Pietro Lura is developing a process for integrating biochar into concrete.

Difficulties due to porosity

Biochar is produced by a pyrolytic carbonization process of biomass in the absence of oxygen and consists to a high extent of pure carbon -- the carbon that the plants have extracted from the atmosphere in the form of CO2 as they grow.

While CO2 is emitted when plants are burned, it remains bound in the biochar over the long term.

The first concrete products with integrated biochar are already on the market.

However, biochar is often introduced into the concrete untreated, which can lead to difficulties.

"Biochar is very porous and therefore not only absorbs a lot of water, but also expensive admixtures used in concrete production," explains Empa researcher Mateusz Wyrzykowski.

"Moreover, it is difficult to handle and not completely harmless either." The fine coal dust is problematic for the respiratory tract and carries a certain risk of explosion.

For these reasons, the researchers propose in a paper that has just published in the Journal of Cleaner Production processing the biochar into pellets.

"Such lightweight aggregates already exist from other materials such as expanded clay or fly ash. The knowhow in handling these materials is available in industry, and this increases the chances that the concept will be put into practice," says Wyrzykowski.

Net zero at 20 percent share

To produce the pellets, the team used a concrete mixer with a rotating pan in which they mixed the biochar with water and cement and, as a result of the rotation, obtained small pellets with a diameter of between 4 and 32 millimeters.

In turn, they used these pellets to produce normal concrete of strength classes C20/25 to C30/37 -- the classes that are most widely used in civil engineering today.

"With a proportion of 20 percent by volume of carbon pellets in the concrete, we achieve net zero emissions," says Mateusz Wyrzykowski.

That is, the amount of carbon stored offsets all the emissions produced in the production of both the pellets and the concrete.

While the limit has probably not yet been reached for normal concrete (density between 2,000 and 2,600 kg/m3) with 20 percent by volume, the negative emission potential is particularly striking for lightweight concrete (density approx.

1,800 kg/m3): An admixture of 45 percent by volume of carbon pellets in the concrete leads to total negative emissions of minus 290 kg CO2/m3. By comparison, conventional concrete emits around 200 kg CO2/m3.

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Could a drug prevent hearing loss from loud music and aging?

Researchers have found a gene that links deafness to cell death in the inner ear in humans -- creating new opportunities for averting hearing loss.

A person's hearing can be damaged by loud noise, aging and even certain medications, with little recourse beyond a hearing aid or cochlear implant.

But now, UCSF scientists have achieved a breakthrough in understanding what is happening in the inner ear during hearing loss, laying the groundwork for preventing deafness.

The research, published on Dec. 22, 2023, in the Journal of Clinical Investigation Insight, links animal studies on hearing loss with a rare type of inherited deafness in humans. In both cases, mutations to the TMTC4 gene trigger a molecular domino effect known as the unfolded protein response (UPR), leading to the death of hair cells in the inner ear.

Intriguingly, hearing loss from loud noise exposure or drugs such as cisplatin, a common form of chemotherapy, also stems from activation of the UPR in hair cells, suggesting that the UPR may underly several different forms of deafness.

There are several drugs that block the UPR -- and stop hearing loss -- in laboratory animals. The new findings make a stronger case for testing these drugs in people who are at risk of losing their hearing, according to the researchers.

"Millions of American adults lose their hearing due to noise exposure or aging each year, but it's been a mystery what was going wrong," said Dylan Chan, MD, PhD, co-senior author on the paper and director of the Children's Communication Center (CCC) in the UCSF Department of Otolaryngology. "We now have solid evidence that TMTC4 is a human deafness gene and that the UPR is a genuine target for preventing deafness."

How hair cells in the ear self-destruct

In 2014, Elliott Sherr, MD, PhD, director of the UCSF Brain Development Research Program and co-senior author of the paper, noticed that several of his young patients with brain malformations all had mutations to TMTC4. But laboratory studies of this gene soon presented a conundrum.

"We expected mice with TMTC4 mutations to have severe brain defects early on, like those pediatric patients, yet to our surprise, they seemed normal at first," Sherr said. "But as those animals grew, we saw that they didn't startle in response to loud noise. They had gone deaf after they had matured."

Sherr partnered with Chan, an expert on the inner ear, to look into what was happening to the mice, which looked like an accelerated version of age-related hearing loss in humans. They showed that mutations to TMTC4 primed hair cells in the ear to self-destruct, and loud noise did the same thing. In both cases, hair cells were flooded with excess calcium, throwing off the balance of other cellular signals, including the UPR.

But they found there was a way to stop this. ISRIB, a drug developed at UCSF to block the UPR's self-destruct mechanism in traumatic brain injury, prevented animals who were exposed to noise from going deaf.

The first adult human deafness gene

In 2020, scientists from South Korea, led by Bong Jik Kim, MD, PhD, connected Chan and Sherr's 2018 findings with genetic mutations they found in two siblings who were losing their hearing in their mid-20s. The mutations were in TMTC4 and matched what Chan and Sherr had seen in animals, although they were distinct from those in Sherr's pediatric neurology patients.

"It's rare to so quickly connect mouse studies with humans," Sherr said. "Thanks to our Korean collaborators, we could more easily prove the relevance of our work for the many people who go deaf over time."

Kim, an otolaryngologist at the Chungnam National University College of Medicine (Korea), facilitated the shipping of cells from those patients to UCSF. Sherr and Chan tested those cells for UPR activity and found that, indeed, this flavor of TMTC4 mutation turned on the destructive UPR pathway in a human context.

When Chan and Sherr mutated TMTC4 only in hair cells in mice, the mice went deaf. When they mutated TMTC4 in cells from individuals in the Korean family who hadn't gone deaf, and in laboratory human cell lines, the UPR drove the cells to self-destruct. TMTC4 was more than a deafness gene in mice -- it was a deafness gene in humans, too.

Translating a discovery to prevent deafness

Understanding TMTC4 mutations gives researchers a new way of studying progressive deafness, since it is critical for maintaining the health of the adult inner ear. The mutations mimic damage from noise, aging or drugs like cisplatin.

The researchers envision a future where people who must take cisplatin, or who have to be exposed to loud noises for their jobs, take a drug that dampens the UPR and keeps hair cells from withering away, preserving their hearing.

The science also suggests that the UPR could be targeted in other contexts where nerve cells become overwhelmed and die, including diseases long thought to be incurable, like Alzheimer's or Lou Gehrig's disease.

Read more at Science Daily

Mysterious missing component in the clouds of Venus revealed

What are the clouds of Venus made of? Scientists know it's mainly made of sulfuric acid droplets, with some water, chlorine, and iron. Their concentrations vary with height in the thick and hostile Venusian atmosphere. But until now they have been unable to identify the missing component that would explain the clouds' patches and streaks, only visible in the UV range.

In a new study published in Science Advances, researchers from the University of Cambridge synthesised iron-bearing sulfate minerals that are stable under the harsh chemical conditions in the Venusian clouds.

Spectroscopic analysis revealed that a combination of two minerals, rhomboclase and acid ferric sulfate, can explain the mysterious UV absorption feature on our neighbouring planet.

"The only available data for the composition of the clouds were collected by probes and revealed strange properties of the clouds that so far we have been unable to fully explain," said Paul Rimmer from the Cavendish Laboratory and co-author of the study.

"In particular, when examined under UV light, the Venusian clouds featured a specific UV absorption pattern. What elements, compounds, or minerals are responsible for such observation?"

Formulated on the basis of Venusian atmospheric chemistry, the team synthesized several iron-bearing sulfate minerals in an aqueous geochemistry laboratory in the Department of Earth Sciences.

By suspending the synthesized materials in varying concentrations of sulfuric acid and monitor the chemical and mineralogical changes, the team narrowed down the candidate minerals to rhomboclase and acid ferric sulfate, of which the spectroscopic features were examined under light sources specifically designed to mimic the spectrum of solar flares (Paul Rimmer and Samantha Thompson's FlareLab at the Cavendish Laboratory).

A photochemistry lab at Harvard collaborated in the research by providing measurements of the UV absorbance patterns of ferric iron under extreme acidic conditions, in an attempt to mimic the even more extreme Venusian clouds.

The scientists are part of the newly established Origins Federation, which promotes such collaborative projects.

"The patterns and level of absorption shown by the combination of these two mineral phases are consistent with the dark UV-patches observed in Venusian clouds," said co-author Clancy Zhijian Jiang, from the Department of Earth Sciences, Cambridge.

"These targeted experiments revealed the intricate chemical network within the atmosphere, and shed light on the elemental cycling on the Venusian surface."

"Venus is our nearest neighbour, but it remains a mystery," said Rimmer.

"We will have a chance to learn much more about this planet in the coming years with future NASA and ESA missions set to explore its atmosphere, clouds and surface. This study prepares the grounds for these future explorations."

Read more at Science Daily

Arctic cold snap transforms into a blessing

A recent cold spell plunged the nation of Korea into a deep freeze, resulting in the closure of 247 national parks, the cancellation of 14 domestic flights, and the scrapping of 107 cruise ship voyages. While the cold snap brought relief by significantly reducing the prevalence of particulate matter obscuring our surroundings, a recent study indicates that, besides diminishing particulate matter, it is significantly contributing to the heightened uptake of carbon dioxide by the East Sea.

According to research conducted by a team of researchers including Professor Kitack Lee from the Division of Environmental Science & Engineering at Pohang University of Science and Technology (POSTECH), and Professor Tongsup Lee and So-Yun Kim from the Department of Oceanography at Pusan National University, the cold atmosphere in the Arctic is influencing the absorption of carbon dioxide by the East Sea.

The research findings were published in Geophysical Research Letters, an international journal by the American Geophysical Union (AGU).

The research team investigated the correlation between the East Sea's surface-deep circulation and its carbon dioxide absorption capacity, drawing insights from observations in 1992, 1999, 2007, and 2019.

During the initial period (1992-1999), the ocean absorbed 20 million tons of carbon dioxide annually.

In the subsequent period (1999-2007), this amount decreased to under 10 million tons per year.

However, in the final period (2007-2019), the carbon dioxide uptake surged to 30 million tons per year.

The team observed that the internal circulation along the East Coast within the East Sea was influenced by the Arctic cold wave.

Cold air from the Arctic infiltrates the East Sea, causing the surface water, laden with carbon dioxide, to become denser.

This process induces vertical ventilation as the water descends into the middle and deep ocean layers.

Consequently, the intensified descent of cold air from the Arctic strengthens the internal circulation, leading to a heightened uptake of carbon dioxide in the East Sea.

Professor Kitack Lee who led the research remarked, " The oceans represent an immense reservoir of carbon dioxide and offer a secure and sustainable avenue for mitigating atmospheric carbon dioxide levels." He further stated, "It is crucial to anticipate the global ocean's capacity for carbon removal as we navigate future climate changes and identify suitable methods to leverage this potential."

In a related development, the team's earlier research uncovered the mechanism through which the ocean absorbs carbon dioxide.

Approximately half of the carbon dioxide generated by human activities remains in the atmosphere with the other half entering marine and terrestrial ecosystems.

With a carbon content 400,000 times greater than that of the atmosphere, the oceans present vast and promising potential for storing carbon dioxide.

Read more at Science Daily

Protected areas for elephants work best if they are connected

Conservation measures have successfully stopped declines in the African savanna elephant population across southern Africa, but the pattern varies locally, according to a new study.

The evidence suggests that the long-term solution to elephant survival requires not only that areas are protected but that they are also connected to allow populations to stabilize naturally, an international research team says.

Their study, published on January 5th in the peer-reviewed journal Science Advances, collected survey estimates and calculated growth rates for more than 100 elephant populations in southern Africa between 1995 and 2020, accounting for an estimated 70% of the global savanna elephant population.

"This is the most comprehensive analysis of growth rates for any large mammal population in the world," said co-author Rob Guldemond, director of the Conservation Ecological Research Unit (CERU) at the University of Pretoria, in South Africa.

Overall, the survey's results are positive: There are the same number of elephants now as there were 25 years ago, a rare conservation win at a time when the planet is rapidly losing biodiversity.

However, the pattern is not consistent across regions. Some areas, such as south Tanzania, eastern Zambia, and northern Zimbabwe, experienced severe declines due to illegal ivory poaching.

In contrast, populations in other regions like north Botswana are booming.

"Unchecked growth isn't necessarily a good thing, however," says study co-author Stuart Pimm, the Doris Duke Professor of Conservation at Duke University in North Carolina.

"Rapidly increasing populations can outgrow and damage their local environment and prove hard to manage -- introducing a threat to their long-term stability," Pimm says.

In addition to documenting local growth rates, the team also looked at the features of the local populations to identify what makes them stable, that is neither growing nor declining.

Elephant populations in well-protected but isolated parks, sometimes called "fortress conservation," grow rapidly in the absence of threats but are unsustainable in the long term.

These elephants will likely need future conservation interventions, such as translocation or birth control, which are both costly and intensive endeavors.

The team found that the most stable populations occur in large, core areas that are surrounded by buffer zones.

The core areas are defined by their strong levels of environmental protection and minimal human impact, whereas the buffers allow some activities such as sustainable farming, forestry, or trophy hunting.

Unlike the insular fortresses, core areas are connected to other parks, allowing herds to move naturally.

"What's crucial is that you need a mix of areas with more stable core populations linked to more variable buffer areas," said lead author Ryan Huang, a Duke Ph.D. now doing postdoctoral research at CERU.

"These buffers absorb immigrants when core populations get too high, but also provide escape routes when elephants face poor environmental conditions or other threats such as poaching," Huang said.

Connecting protected areas means elephants can freely move in and out.

This allows a natural equilibrium to occur without human intervention, sparing conservationists from using their limited resources to maintain balance.

"Calling for connecting parks isn't something new. Many have done so," Huang said.

"But surprisingly, there has not been a lot of published evidence of its effectiveness so far. This study helps quantify why this works."

Read more at Science Daily