Engineers develop all-in-one solution to catch and destroy 'forever chemicals'

Chemical engineers at the University of British Columbia have developed a new treatment that traps and treats PFAS substances -- widely known as "forever chemicals" -- in a single, integrated system.

Per- and polyfluoroalkyl substances (PFAS) are widely used in manufacturing consumer goods like waterproof clothing due to their resistance to heat, water and stains. However, they are also pollutants, often ending up in surface and groundwater worldwide, where they have been linked to cancer, liver damage and other health issues.

"PFAS are notoriously difficult to break down, whether they're in the environment or in the human body," explained lead researcher Dr. Johan Foster, an associate professor of chemical and biological engineering in the faculty of applied science. "Our system will make it possible to remove and destroy these substances in the water supply before they can harm our health."

Catch and destroy

The UBC system combines an activated carbon filter with a special, patented catalyst that traps harmful chemicals and breaks them down into harmless components on the filter material. Scientists refer to this trapping of chemical components as adsorption.

"The whole process is fairly quick, depending on how much water you're treating," said Dr. Foster. "We can put huge volumes of water through this catalyst, and it will adsorb the PFAS and destroy it in a quick two-step process. Many existing solutions can only adsorb while others are designed to destroy the chemicals. Our catalyst system can do both, making it a long-term solution to the PFAS problem instead of just kicking the can down the road."

No light? No problem

Like other water treatments, the UBC system requires ultraviolet light to work, but it does not need as much UV light as other methods.

During testing, the UBC catalyst consistently removed more than 85 per cent of PFOA (perfluorooctanoic acid, a type of forever chemical) even under low light conditions.

"Our catalyst is not limited by ideal conditions. Its effectiveness under varying UV light intensities ensures its applicability in diverse settings, including regions with limited sunlight exposure," said Dr. Raphaell Moreira, a professor at Universität Bremen who conducted the research while working at UBC.

For example, a northern municipality that gets little sun could still benefit from this type of PFAS solution.

"While the initial experiments focused on PFAS compounds, the catalyst's versatility suggests its potential for removing other types of persistent contaminants, offering a promising solution to the pressing issues of water pollution," explained Dr. Moreira.

From municipal water to industry cleanups

The team believes the catalyst could be a low-cost, effective solution for municipal water systems as well as specialized industrial projects like waste stream cleanup.

They have set up a company, ReAct Materials, to explore commercial options for their technology.

"Our catalyst can eliminate up to 90 per cent of forever chemicals in water in as little as three hours -- significantly faster than comparable solutions on the market. And because it can be produced from forest or farm waste, it's more economical and sustainable compared to the more complex and costly methods currently in use," said Dr. Foster.

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Scientists find oceans of water on Mars: It's just too deep to tap

Using seismic activity to probe the interior of Mars, geophysicists have found evidence for a large underground reservoir of liquid water -- enough to fill oceans on the planet's surface.

The data from NASA's Insight lander allowed the scientists to estimate that the amount of groundwater could cover the entire planet to a depth of between 1 and 2 kilometers, or about a mile.

While that's good news for those tracking the fate of water on the planet after its oceans disappeared more than 3 billion years ago, the reservoir won't be of much use to anyone trying to tap into it to supply a future Mars colony. It's located in tiny cracks and pores in rock in the middle of the Martian crust, between 11.5 and 20 kilometers below the surface. Even on Earth, drilling a hole a kilometer deep is a challenge.

The finding does pinpoint another promising place to look for life on Mars, however, if the reservoir can be accessed. For the moment, it helps answer questions about the geological history of the planet.

"Understanding the Martian water cycle is critical for understanding the evolution of the climate, surface and interior," said Vashan Wright, a former UC Berkeley postdoctoral fellow who is now an assistant professor at UC San Diego's Scripps Institution of Oceanography. "A useful starting point is to identify where water is and how much is there."

Wright, alongside colleagues Michael Manga of UC Berkeley and Matthias Morzfeld of Scripps Oceanography, detailed their analysis in a paper that will appear this week in the journal Proceedings of the National Academy of Sciences.

The scientists employed a mathematical model of rock physics, identical to models used on Earth to map underground aquifers and oil fields, to conclude that the seismic data from Insight are best explained by a deep layer of fractured igneous rock saturated with liquid water. Igneous rocks are cooled hot magma, like the granite of the Sierra Nevada.

"Establishing that there is a big reservoir of liquid water provides some window into what the climate was like or could be like," said Manga, a UC Berkeley professor of earth and planetary science. "And water is necessary for life as we know it. I don't see why [the underground reservoir] is not a habitable environment. It's certainly true on Earth -- deep, deep mines host life, the bottom of the ocean hosts life. We haven't found any evidence for life on Mars, but at least we have identified a place that should, in principle, be able to sustain life."

Manga was Wright's postdoctoral adviser. Morzfeld was a former postdoctoral fellow in UC Berkeley's mathematics department and is now an associate professor of geophysics at Scripps Oceanography.

Manga noted that lots of evidence -- river channels, deltas and lake deposits, as well as water-altered rock -- supports the hypothesis that water once flowed on the planet's surface. But that wet period ended more than 3 billion years ago, after Mars lost its atmosphere. Planetary scientists on Earth have sent many probes and landers to the planet to find out what happened to that water -- the water frozen in Mars' polar ice caps can't account for it all -- as well as when it happened, and whether life exists or used to exist on the planet.

The new findings are an indication that much of the water did not escape into space but filtered down into the crust.

The Insight lander was sent by NASA to Mars in 2018 to investigate the crust, mantle, core and atmosphere, and it recorded invaluable information about Mars' interior before the mission ended in 2022.

"The mission greatly exceeded my expectations," Manga said. "From looking at all the seismic data that Insight collected, they've figured out the thickness of the crust, the depth of the core, the composition of the core, even a little bit about the temperature within the mantle."

Insight detected Mars quakes up to about a magnitude of 5, meteor impacts and rumblings from volcanic areas, all of which produced seismic waves that allowed geophysicists to probe the interior.

An earlier paper reported that above a depth of about 5 kilometers, the upper crust did not contain water ice, as Manga and others suspected. That may mean that there's little accessible frozen groundwater outside the polar regions.

The new paper analyzed the deeper crust and concluded that the "available data are best explained by a water-saturated mid-crust" below Insight's location. Assuming the crust is similar throughout the planet, the team argued, there should be more water in this mid-crust zone than the "volumes proposed to have filled hypothesized ancient Martian oceans."

Read more at Science Daily

Rocks from Mars' Jezero Crater, which likely predate life on Earth, contain signs of water

In a new study appearing today in the journal AGU Advances, scientists at MIT and NASA report that seven rock samples collected along the "fan front" of Mars' Jezero Crater contain minerals that are typically formed in water. The findings suggest that the rocks were originally deposited by water, or may have formed in the presence of water.

The seven samples were collected by NASA's Perseverance rover in 2022 during its exploration of the crater's western slope, where some rocks were hypothesized to have formed in what is now a dried-up ancient lake. Members of the Perseverance science team, including MIT scientists, have studied the rover's images and chemical analyses of the samples, and confirmed that the rocks indeed contain signs of water, and that the crater was likely once a watery, habitable environment.

Whether the crater was actually inhabited is yet unknown. The team found that the presence of organic matter -- the starting material for life -- cannot be confirmed, at least based on the rover's measurements. But judging from the rocks' mineral content, scientists believe the samples are their best chance of finding signs of ancient Martian life once the rocks are returned to Earth for more detailed analysis.

"These rocks confirm the presence, at least temporarily, of habitable environments on Mars," says the study's lead author, Tanja Bosak, professor of geobiology in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). "What we've found is that indeed there was a lot of water activity. For how long, we don't know, but certainly for long enough to create these big sedimentary deposits."

What's more, some of the collected samples may have originally been deposited in the ancient lake more than 3.5 billion years ago -- before even the first signs of life on Earth.

"These are the oldest rocks that may have been deposited by water, that we've ever laid hands or rover arms on," says co-author Benjamin Weiss, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. "That's exciting, because it means these are the most promising rocks that may have preserved fossils, and signatures of life."

The study's MIT co-authors include postdoc Eva Scheller, and research scientist Elias Mansbach, along with members of the Perseverance science team.

At the front

The new rock samples were collected in 2022 as part of the rover's Fan Front Campaign -- an exploratory phase during which Perseverance traversed Jezero Crater's western slope, where a fan-like region contains sedimentary, layered rocks. Scientists suspect that this "fan front" is an ancient delta that was created by sediment that flowed with a river and settled into a now bone-dry lakebed. If life existed on Mars, scientists believe that it could be preserved in the layers of sediment along the fan front.

In the end, Perseverance collected seven samples from various locations along the fan front. The rover obtained each sample by drilling into the Martian bedrock and extracting a pencil-sized core, which it then sealed in a tube to one day be retrieved and returned to Earth for detailed analysis.

Prior to extracting the cores, the rover took images of the surrounding sediments at each of the seven locations. The science team then processed the imaging data to estimate a sediment's average grain size and mineral composition. This analysis showed that all seven collected samples likely contain signs of water, suggesting that they were initially deposited by water.

Specifically, Bosak and her colleagues found evidence of certain minerals in the sediments that are known to precipitate out of water.

"We found lots of minerals like carbonates, which are what make reefs on Earth," Bosak says. "And it's really an ideal material that can preserve fossils of microbial life."

Interestingly, the researchers also identified sulfates in some samples that were collected at the base of the fan front. Sulfates are minerals that form in very salty water -- another sign that water was present in the crater at one time -- though very salty water, Bosak notes, "is not necessarily the best thing for life." If the entire crater was once filled with very salty water, then it would be difficult for any form of life to thrive. But if only the bottom of the lake were briny, that could be an advantage, at least for preserving any signs of life that may have lived further up, in less salty layers, that eventually died and drifted down to the bottom.

"However salty it was, if there were any organics present, it's like pickling something in salt," Bosak says. "If there was life that fell into the salty layer, it would be very well-preserved."

Fuzzy fingerprints

But the team emphasizes that organic matter has not been confidently detected by the rover's instruments. Organic matter can be signs of life, but can also be produced by certain geological processes that have nothing to do with living matter. Perseverance's predecessor, the Curiosity rover, had detected organic matter throughout Mars' Gale Crater, which scientists suspect may have come from asteroids that made impact with Mars in the past.

And in a previous campaign, Perseverance detected what appeared to be organic molecules at multiple locations along Jezero Crater's floor. These observations were taken by the rover's Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument, which uses ultraviolet light to scan the Martian surface. If organics are present, they can glow, similar to material under a blacklight. The wavelengths at which the material glows act as a sort of fingerprint for the kind of organic molecules that are present.

In Perseverance's previous exploration of the crater floor, SHERLOC appeared to pick up signs of organic molecules throughout the region, and later, at some locations along the fan front. But a careful analysis, led by MIT's Eva Scheller, has found that while the particular wavelengths observed could be signs of organic matter, they could just as well be signatures of substances that have nothing to do with organic matter.

"It turns out that cerium metals incorporated in minerals actually produce very similar signals as the organic matter," Scheller says. "When investigated, the potential organic signals were strongly correlated with phosphate minerals, which always contain some cerium."

Scheller's work shows that the rover's measurements cannot be interpreted definitively as organic matter.

"This is not bad news," Bosak says. "It just tells us there is not very abundant organic matter. It's still possible that it's there. It's just below the rover's detection limit."

When the collected samples are finally sent back to Earth, Bosak says laboratory instruments will have more than enough sensitivity to detect any organic matter that might lie within.

Read more at Science Daily

A virus could help save billions of gallons of wastewater produced by fracking

An estimated 168 billion gallons of wastewater -- or produced water -- is generated annually by the Permian Basin fracking industry, according to a 2022 report by the Texas Produced Water Consortium. The major waste stream has proved both difficult and costly to treat because of the chemical complexity of the water.

In a new study published in the journal Water, researchers at The University of Texas at El Paso have identified a novel means of treating the wastewater generated by oil and gas production: bacteriophages.

Ramón Antonio Sánchez, a doctoral candidate within UTEP's chemistry program, is the first author on the publication, detailing how bacteriophages, viruses that are often highly specific and lethal to a single species of bacteria, can be used as a rapid and cost-effective method to treat produced water on an industrial scale.

Sánchez said if the work is successful, it would give the oil and gas industry a means of treating, reusing and recycling produced water, rather than the current industry practice of disposing the majority of produced water by injecting it into the ground post oil exploration.

The research focuses on two of the most prominent bacteria found within produced water across the oil and gas industry -- Pseudomonas aeruginosa and Bacillus megaterium. P. aeruginosa has the ability to corrode stainless steel and presents a challenge for the longevity of pipelines and other metal-based infrastructure, while B. megaterium, can decompose hydrocarbons -- the basis for oil.

Sánchez, along with one of his collaborators, Zacariah Hildenbrand, Ph.D., a UTEP alum, were inspired to use bacteriophages based on their applications in the medical industry, where they are used to combat infections caused by multi-drug resistant bacteria.

"Since the bacteria are living organisms, over time they developed a resistance, in the form of a less penetrable membrane, to traditional disinfectants," Sánchez explained. "But the bacteriophages, which are viruses themselves, attach to specific receptors on the surface of the host cell and evolve alongside the bacteria they are trying to infect, meaning that any resistance acquired by the bacteria triggers the modification of bacteriophages to keep the infection going."

The team's experiments with bacteriophages have been effective, achieving the inactivation of both P. aeruginosa and B. megaterium in laboratory settings. For Sánchez, who graduates this spring with his Ph.D., the work will continue in the industry where his focus will be on replicating his laboratory results out in the field. He will also try to expand the number of microorganisms that can be treated in produced water by securing a larger catalog of bacteriophages.

Read more at Science Daily

How light can vaporize water without the need for heat

It's the most fundamental of processes -- the evaporation of water from the surfaces of oceans and lakes, the burning off of fog in the morning sun, and the drying of briny ponds that leaves solid salt behind. Evaporation is all around us, and humans have been observing it and making use of it for as long as we have existed.

And yet, it turns out, we've been missing a major part of the picture all along.

In a series of painstakingly precise experiments, a team of researchers at MIT has demonstrated that heat isn't alone in causing water to evaporate. Light, striking the water's surface where air and water meet, can break water molecules away and float them into the air, causing evaporation in the absence of any source of heat.

The astonishing new discovery could have a wide range of significant implications. It could help explain mysterious measurements over the years of how sunlight affects clouds, and therefore affect calculations of the effects of climate change on cloud cover and precipitation. It could also lead to new ways of designing industrial processes such as solar-powered desalination or drying of materials.

The findings, and the many different lines of evidence that demonstrate the reality of the phenomenon and the details of how it works, are described in the journal PNAS, in a paper by Carl Richard Soderberg Professor of Power Engineering Gang Chen, postdocs Guangxin Lv and Yaodong Tu, and graduate student James Zhang.

The authors say their study suggests that the effect should happen widely in nature -- everywhere from clouds to fogs to the surfaces of oceans, soils, and plants -- and that it could also lead to new practical applications, including in energy and clean water production. "I think this has a lot of applications," Chen says. "We're exploring all these different directions. And of course, it also affects the basic science, like the effects of clouds on climate, because clouds are the most uncertain aspect of climate models."

A newfound phenomenon

The new work builds on research reported last year, which described this new "photomolecular effect" but only under very specialized conditions: on the surface of specially prepared hydrogels soaked with water. In the new study, the researchers demonstrate that the hydrogel is not necessary for the process; it occurs at any water surface exposed to light, whether it's a flat surface like a body of water or a curved surface like a droplet of cloud vapor.

Because the effect was so unexpected, the team worked to prove its existence with as many different lines of evidence as possible. In this study, they report 14 different kinds of tests and measurements they carried out to establish that water was indeed evaporating -- that is, molecules of water were being knocked loose from the water's surface and wafted into the air -- due to the light alone, not by heat, which was long assumed to be the only mechanism involved.

One key indicator, which showed up consistently in four different kinds of experiments under different conditions, was that as the water began to evaporate from a test container under visible light, the air temperature measured above the water's surface cooled down and then leveled off, showing that thermal energy was not the driving force behind the effect.

Other key indicators that showed up included the way the evaporation effect varied depending on the angle of the light, the exact color of the light, and its polarization. None of these varying characteristics should happen because at these wavelengths, water hardly absorbs light at all -- and yet the researchers observed them.

The effect is strongest when light hits the water surface at an angle of 45 degrees. It is also strongest with a certain type of polarization, called transverse magnetic polarization. And it peaks in green light -- which, oddly, is the color for which water is most transparent and thus interacts the least.

Chen and his co-researchers have proposed a physical mechanism that can explain the angle and polarization dependence of the effect, showing that the photons of light can impart a net force on water molecules at the water surface that is sufficient to knock them loose from the body of water. But they cannot yet account for the color dependence, which they say will require further study.

They have named this the photomolecular effect, by analogy with the photoelectric effect that was discovered by Heinrich Hertz in 1887 and finally explained by Albert Einstein in 1905. That effect was one of the first demonstrations that light also has particle characteristics, which had major implications in physics and led to a wide variety of applications, including LEDs. Just as the photoelectric effect liberates electrons from atoms in a material in response to being hit by a photon of light, the photomolecular effect shows that photons can liberate entire molecules from a liquid surface, the researchers say.

"The finding of evaporation caused by light instead of heat provides new disruptive knowledge of light-water interaction," says Xiulin Ruan, professor of mechanical engineering at Purdue University, who was not involved in the study. "It could help us gain new understanding of how sunlight interacts with cloud, fog, oceans, and other natural water bodies to affect weather and climate. It has significant potential practical applications such as high-performance water desalination driven by solar energy. This research is among the rare group of truly revolutionary discoveries which are not widely accepted by the community right away but take time, sometimes a long time, to be confirmed."

Solving a cloud conundrum

The finding may solve an 80-year-old mystery in climate science. Measurements of how clouds absorb sunlight have often shown that they are absorbing more sunlight than conventional physics dictates possible. The additional evaporation caused by this effect could account for the longstanding discrepancy, which has been a subject of dispute since such measurements are difficult to make.

"Those experiments are based on satellite data and flight data," Chen explains. "They fly an airplane on top of and below the clouds, and there are also data based on the ocean temperature and radiation balance. And they all conclude that there is more absorption by clouds than theory could calculate. However, due to the complexity of clouds and the difficulties of making such measurements, researchers have been debating whether such discrepancies are real or not. And what we discovered suggests that hey, there's another mechanism for cloud absorption, which was not accounted for, and this mechanism might explain the discrepancies."

Chen says he recently spoke about the phenomenon at an American Physical Society conference, and one physicist there who studies clouds and climate said they had never thought about this possibility, which could affect calculations of the complex effects of clouds on climate. The team conducted experiments using LEDs shining on an artificial cloud chamber, and they observed heating of the fog, which was not supposed to happen since water does not absorb in the visible spectrum. "Such heating can be explained based on the photomolecular effect more easily," he says.

Lv says that of the many lines of evidence, "the flat region in the air-side temperature distribution above hot water will be the easiest for people to reproduce." That temperature profile "is a signature" that demonstrates the effect clearly, he says.

Zhang adds: "It is quite hard to explain how this kind of flat temperature profile comes about without invoking some other mechanism" beyond the accepted theories of thermal evaporation. "It ties together what a whole lot of people are reporting in their solar desalination devices," which again show evaporation rates that cannot be explained by the thermal input.

The effect can be substantial. Under the optimum conditions of color, angle, and polarization, Lv says, "the evaporation rate is four times the thermal limit."

Already, since publication of the first paper, the team has been approached by companies that hope to harness the effect, Chen says, including for evaporating syrup and drying paper in a paper mill. The likeliest first applications will come in the areas of solar desalinization systems or other industrial drying processes, he says. "Drying consumes 20 percent of all industrial energy usage," he points out.

Read more at Science Daily

World's oases threatened by desertification, even as humans expand them

Oases are important habitats and water sources for dryland regions, sustaining 10% of the world's population despite taking up about 1.5% of land area. But in many places, climate change and anthropogenic activities threaten oases' fragile existence. New research shows how the world's oases have grown and shrunk over the past 25 years as water availability patterns changed and desertification encroaches on these wet refuges.

"Although the scientific community has always emphasized the importance of oases, there has not been a clear map of the global distribution of oases," said Dongwei Gui, a geoscientist at the Chinese Academy of Science who led the study. "Oasis research has both theoretical and practical significance for achieving United Nations Sustainable Development Goals and promoting sustainable development in arid regions."

The study found that oases around the world grew by more than 220,149 square kilometers (85,000 square miles) from 1995 to 2020, mostly due to intentional oasis expansion projects in Asia. But desertification drove the loss of 134,300 square kilometers (51,854 square miles) of oasis over the same period, also mostly in Asia, leading to a net growth of 86,500 square kilometers (about 33,400 square miles) over the study period.

The findings highlight the risk climate change and anthropogenic stressors pose to these wet sanctuaries and can inform water resource management and sustainable development in arid regions. The study was published in the AGU journal Earth's Future, which publishes interdisciplinary research on the past, present and future of our planet and its inhabitants.

The birth and death of an oasis

Oases are important sources of water for humans, plants and animals in the world's drylands, supporting a majority of productivity and life in deserts. They form when groundwater flows and settles into low-lying areas, or when surface meltwater flows downslope from adjacent mountain ranges and pools. The existence of an oasis depends primarily on having a reliable source of water that is not rainfall. Today, oases are found in 37 countries; 77% of oases are located in Asia, and 13% are found in Australia.

Gui and his co-investigators wanted to understand the global distribution and dynamic changes of oases and see how they respond to a changing environment, such as variations in climate, water resources and human activities. Using data from the European Space Agency's Climate Change Initiative Land Cover Product, the team categorized the land surface into seven categories: forest, grassland, shrub, cropland, water, urban and desert.

The researchers used satellite data to look for green, vegetated areas within dryland areas, indicating an oasis, and tracked changes over 25 years. Changes in the greenness of vegetation indicated changes in land use and oasis health, the latter of which can be influenced by both human activity and climate change. They also looked at changes in land surface type to find conversions of land use.

The researchers found that global oasis area increased by 220,800 square kilometers (85,251 square miles) over the 25-year timeframe. Most of that increase was from humans intentionally converting desert land into oases using runoff water and groundwater pumping, creating grasslands and croplands. The increase was concentrated in China, where management efforts have contributed more than 60% of the growth, Gui said. For example, more than 95% of the population in China's Xinjiang Uygur Autonomous Region lives within an oasis, motivating conservation and a 16,700 square kilometer (6,448 square mile) expansion of the oasis, Gui said.

Countering human efforts to expand oases, desertification contributed to oasis loss. Worldwide, the researchers found there was a loss of more than 134,000 square kilometers (51,738 square miles) of oasis land over the past 25 years. The researchers estimate that changes to oases have directly affected about 34 million people around the world.

Overall, between gains and losses, oases had a net growth of 86,500 square kilometers (33,397 square miles) from 1995 to 2020 -- but most gains were from the artificial expansion of oases, which may not be sustainable in the future.

Long-term oasis sustainability

The study highlighted ways to sustain healthy oases, including suggestions for improving water resource management, promoting sustainable land use and management and encouraging water conservation and efficient use. These efforts are especially important as the climate continues to change, Gui said.

Humans' overexploitation of dwindling groundwater can limit oasis sustainability, as well as long-term glacier loss. While higher temperatures increase glacier melt, temporarily boosting oases' water supplies, "as glaciers gradually disappear, the yield of meltwater will eventually decrease, leading to the shrinkage of oases once again," Gui said.

International cooperation plays a crucial role in oasis sustainability, Gui said.

"Due to the unique mechanism of oasis formation, a river basin often nurtures multiple oases across several countries, making transboundary cooperation key to addressing water scarcity and promoting sustainable development," he said.

Read more at Science Daily

New approach needed to save Australia's non-perennial rivers

Non-perennial rivers, which stop flowing at some point each year, dominate surface water movement across Australia, yet monitoring the continued health of these vital waterways demands a new type of research attention.

More than 70% of this nation's rivers are non-perennial due to a combination of ancient landscape, dry climates, highly variable rainfall regimes, and human interventions that have altered riverine environments.

An extensive review of current research incorporating geomorphology, hydrology, biogeochemistry, ecology and Indigenous knowledges identifies prevailing factors that shape water and energy flows in Australia's non-perennial rivers -- but the review also points to research deficiencies that must be addressed if these river systems are to be preserved and protected.

"Australia relies on our rivers, and has a strong history of research to understand river flows and ecosystems and the human impacts on them. Now, we must address emerging threats to river systems due to climate change and other anthropogenic impacts," says lead author of the review, Dr Margaret Shanafield, from Flinders University's College of Science and Engineering.

"We have to work together to tackle emerging threats to our rivers. If we are going to plug gaps in existing knowledge, which this review identifies, then a new style of inter-disciplinary scientific research is necessary to achieve the required outcomes."

While dominant research themes in Australia focus on drought, floods, salinity, dryland ecology and water management, four other areas of research attention are urgently needed, namely:

•     Integrating Indigenous and western scientific knowledge;
•     Quantifying climate change impacts on hydrological and biological function;
•     Clarifying the meaning and measurement of "restoration" of non-perennial systems;
•     Understanding the role of groundwater.

Addressing these areas through multi-disciplinary efforts supported by technological advances will provide a map for improved water research outcomes that the rest of the world can follow.

"Australia is globally unique in its spread and diversity of non-perennial rivers spanning climates and landforms -- but most, if not all, of the classes of non-perennial rivers found in Australia also occur in other regions of the world with similar climates and geology," says Dr Shanafield.

"Therefore, the evolving body of knowledge about Australian rivers provides a foundation for comparison with other dryland areas globally where recognition of the importance of non-perennial rivers is expanding."

The review authors are concerned that Australian non-perennial river research has been driven by the needs of its inhabitants for survival, agriculture, resource economics, environmental concern and politics.

"Considering the continent's ancient geological history and its harsh, arid climate, it comes as no surprise that significant attention has been directed toward water resource management during drought periods, the reduction of salinisation, and gaining insights into the intricate dynamics of the transient rivers that are a defining feature of central Australia," says the review.

"The prevalence of prolonged drought periods has had a marked impact on driving research -- so it is critical to address the knowledge gaps this review has identified, given that increasing trends in hydrological droughts are projected to negatively impact streamflow not just in Australia, but also in South America, southern Africa, and the Mediterranean."

The review authors -- a multi-disciplinary collective of scientists from across more than two dozen institutions and government departments -- say more investment in long-term hydrological monitoring is desperately needed to increase water management knowledge that can address the competing water needs of communities, agriculture, mining and ecosystems in a dry environment -- not only in Australia, but throughout the world.

"We anticipate that changing global water fluxes and continued groundwater pumping will cause more of the world's rivers to become non-perennial, accelerating our need to understand these systems across many disciplines," says Dr Shanafield.

Read more at Science Daily

Researchers envision sci-fi worlds involving changes to atmospheric water cycle

Human activity is changing the way water flows between the Earth and atmosphere in complex ways and with likely long-lasting consequences that are hard to picture.

Land use change is altering where clouds form and how precipitation is distributed. Meanwhile, weather modification activities like cloud seeding are shifting how nations plan for water use in the face of climate change. These and other changes to the planet's atmospheric water cycle were once hard to imagine but are increasingly part of modern water management on the planet.

Colorado State University Assistant Professor Patrick Keys is an expert in climate and societal change. He has been studying these types of issues for years and realized there was a potential gap when it came to understanding -- not only in the public but among the water research community -- the lasting implications of these changes.

To better grasp how those kinds of activities could shape the world, he enlisted water scientists from around the globe to write story-based scenarios about the possible futures humanity is facing but perhaps can't quite comprehend yet. The results were recently published in Global Sustainability as part of a creative pathway to understand atmospheric water research with an eye towards the potential economic and policy issues that may be just beyond the horizon.

The work features striking artist-made images that pair with traditional science fiction narratives as well as alternative story forms like first-person journal entries. Keys said the package offers a wide path -- grounded in science -- to build a shared understanding of future water management activities and problems.

"Stories are everywhere and are an integral part of human life," he said. "They tell you something different from a graph in a research paper. They allow you to explore how people may feel or react to these kinds of changes. This kind of work provides agency for people and an opportunity to consider these changes no matter their background or level of understanding."

Research for this work came in three distinct phases, according to Keys. First, he used computational text analysis to find recurring themes in journal abstracts about the current state of atmospheric water cycle research. He then sorted the data -- identifying clusters of recurring terms against a grid of common economic goods principles for discussion. The goal, he said, was to better describe the ways humans and institutions may interact with the atmospheric water cycle in the future. Specifically: how entities in the future, such as countries or private actors, could eventually act to protect their own resources or how they may leverage advantages to gain access to water as a crucial natural resource in the future.

It's those relationships and interactions, Keys wanted to explore in the third part of this research and where science fiction comes into play.

Science fiction and reality of atmospheric water resources beyond 2050 With a better grip on the potential future relationships of water management in this space, Keys next asked experts to imagine a world that is decades in the future where activities like cloud seeding were common and the long-term results are more apparent.

The result was an exercise in science fiction storytelling with the specific goal of probing reality and envisioning even the weirdest possible outcomes.

"I think we have a sense that some futures are more likely than others, but we need to realize that to adequately cover the possible trajectories our world could head toward, models alone may not cut it," he said. "Especially when we are talking about things that are hard to quantify, like culture or perception, that may wind up playing a large part in the actual outcomes."

To create the narratives Keys hosted a series of workshops with interdisciplinary water experts from all fields and backgrounds and walked them through a 'futures thinking' approach. The experts were not siloed by discipline and topic during the exercise, with the hope of sparking even more creativity. In the end, 10 story-based scenarios were developed and are included in the paper. Keys also worked with the artist Fabio Comin over the course of a year to create the accompanying imagery.

Keys is based in the Department of Atmospheric Science in the Walter Scott, Jr. College of Engineering. He had several partners in the paper including postdoctoral fellow Rekha Warrier from the Human Dimensions of Natural Resources Department at CSU. Other researchers came from the University of California, Davis, the University of California, Los Angeles, the Stockholm Resilience Centre, and the Potsdam Institute for Climate Impact Research.

Keys said he is now using similar approaches for another project with the Colorado Water Center. He added that one of his goals with both projects was to ignite conversations around the water cycle at what is becoming a key moment for action globally.

Read more at Science Daily

Land under water: What causes extreme flooding?

If rivers overflow their banks, the consequences can be devastating -- just like the catastrophic floods in North Rhine-Westphalia and Rhineland-Palatinate of 2021 showed. In order to limit flood damage and optimise flood risk assessment, we need to better understand what factors can lead to extreme forms of flooding and to what extent. Using methods of explainable machine learning, researchers at the Helmholtz Centre for Environmental Research (UFZ) have shown that floods are more extreme when several factors are involved in their development. The research was published in Science Advances.

There are several factors that play an important role in the development of floods: air temperature, soil moisture, snow depth, and the daily precipitation in the days before a flood. In order to better understand how individual factors contribute to flooding, UFZ researchers examined more than 3,500 river basins worldwide and analysed flood events between 1981 and 2020 for each of them. The result: precipitation was the sole determining factor in only around 25% of the almost 125,000 flood events. Soil moisture was the decisive factor in just over 10% of cases, and snow melt and air temperature were the sole factors in only around 3% of cases. In contrast, 51.6% of cases were caused by at least two factors. At around 23%, the combination of precipitation and soil moisture occurs most frequently.

However, when analysing the data, the UFZ researchers discovered that three -- or even all four -- factors can be jointly responsible for a flood event. For example, temperature, soil moisture, and snow depth were decisive factors in around 5,000 floods whilst all four factors were decisive in around 1,000 flood events. And not only that: "We also showed that flood events become more extreme when more factors are involved," says Dr Jakob Zscheischler, Head of the UFZ Department "Compound Environmental Risks" and senior author of the article. In the case of one-year floods, 51.6% can be attributed to several factors; in the case of five- and ten-year floods, 70.1% and 71.3% respectively can be attributed to several factors. The more extreme a flood is, the more driving factors there are and the more likely they are to interact in the event generation. This correlation often also applies to individual river basins and is referred to as flood complexity.

According to the researchers, river basins in the northern regions of Europe and America as well as in the Alpine region have a low flood complexity. This is because snow melt is the dominant factor for most floods regardless of the flood magnitude. The same applies to the Amazon basin, where the high soil moisture resulting from the rainy season is often a major cause of floods of varying severity. In Germany, the Havel and the Zusam, a tributary of the Danube in Bavaria, are river basins that have a low flood complexity. Regions with river basins that have a high flood complexity primarily include eastern Brazil, the Andes, eastern Australia, the Rocky Mountains up to the US west coast, and the western and central European plains. In Germany, this includes the Moselle and the upper reaches of the Elbe. "River basins in these regions generally have several flooding mechanisms," says Jakob Zscheischler. For example, river basins in the European plains can be affected by flooding caused by the combination of heavy precipitation, active snow melt, and high soil moisture.

However, the complexity of flood processes in a river basin also depends on the climate and land surface conditions in the respective river basin. This is because every river basin has its own special features. Among other things, the researchers looked at the climate moisture index, the soil texture, the forest cover, the size of the river basin, and the river gradient. "In drier regions, the mechanisms that lead to flooding tend to be more heterogeneous. For moderate floods, just a few days of heavy rainfall is usually enough. For extreme floods, it needs to rain longer on already moist soils," says lead author Dr Shijie Jiang, who now works at the Max Planck Institute for Biogeochemistry in Jena.

The scientists used explainable machine learning for the analysis. "First, we use the potential flood drivers air temperature, soil moisture, and snow depth as well as the weekly precipitation -- each day is considered as an individual driving factor -- to predict the run-off magnitude and thus the size of the flood," explains Zscheischler. The researchers then quantified which variables and combinations of variables contributed to the run-off of a particular flood and to which extent. This approach is referred to as explainable machine learning because it uncovers the predictive relationship between flood drivers and run-off during a flood in the trained model. "With this new methodology, we can quantify how many driving factors and combinations thereof are relevant for the occurrence and intensity of floods," adds Jiang.

Read more at Science Daily

Oregon State researchers take deep dive into how much water is stored in snow

A heavy snowpack is fun for skiers and sledders, and it also acts like an open-air storage tank that melts away to provide water for drinking, irrigation and other purposes during dry months.

But exactly how much water is held in snowpacks, and for how long?

That information, critical to water managers around the globe, has taken on new clarity thanks to a new, more holistic calculation technique developed by researchers in the Oregon State University College of Engineering.

"Water managers tend to consider a portfolio of infrastructure options -- surface water reservoirs, groundwater recharge programs, etc. -- to match supply to demand," OSU's David Hill said. "Increased understanding of how much water is in snow should allow them to make long-term planning decisions for how to adjust that portfolio."

The study by Hill, a professor of civil engineering, and doctoral student Christina Aragon looked at nearly four decades of snowpack data. Through their new metric, which they call snow water storage, they identified a 22% drop in how much water is held annually in the mountain snowpacks of the lower 48 states.

"Unlike other widely used metrics that capture snow variables at a single point in time, like maximum snow water equivalent, or describe snow characteristics in terms of time, such as length of snow season, snow water storage is applicable at numerous time and space scales," Hill said. "It's really just a cumulative sum, not a maximum value; it's like adding up the number of miles you drive in a given year, rather than just thinking about the 500 you did on one day for your road trip."

In addition to introducing a better tool for gauging how much water is in snowpacks over periods of time, the findings are important because of what the new metric revealed about mountain snowpacks, which play an outsized role in the nation's water storage.

Hill and Aragon note that of all the water stored in the form of snow in the lower 48, 72% of it is in the mountains, though mountains cover just 16% of the total area.

"There are many ways to describe or quantify our snow resources, but some of the traditional measures, such as the April 1st snowpack, increasingly do not tell the full story," Hill said. "We present a new way of describing snow's water storage ability that adds deeper understanding and has more applicability in cases where our snowfall is increasingly intermittent or, regrettably, turning to rain."

The researchers' work, presented in a paper published in Hydrology and Earth System Sciences, builds on a commonly used measurement known as snow water equivalent; as its name implies, it's how much water is left in a container after the snow that was placed in it melts.

"By considering the amount of water held in the snowpack and the amount of time the water is stored as snow, we are able to quantify water storage in different types of snowpacks," Aragon said. "This includes persistent snowpacks, like we typically have at high elevations in the mountains; transient snowpacks, which are typically found at lower elevations; and snowpacks that are transitioning from persistent to transient due to climate warming."

Aragon adds that because the snow water storage metric can be applied to multiple types of snowpacks, it may become increasingly valuable for monitoring and predicting water resources "amidst a future of increased climate variability."

Hill points out that the past several years in the lower 48 have seen a "feast or famine cycle of extremes when it has come to the where and the when of our snow and rain." And in general snowpacks have considerably declined over the past 10 to 20 years.

"That particularly matters in places like Oregon, where 15% of the state's total annual precipitation falls as snow, and our snowpack functions like a reservoir," he said. "It holds back winter precipitation and slowly releases it in spring and early summer. This is useful because, at those times, our rainfall has tapered off for the year, but demand for water is on the rise."

As the climate warms and snowpacks become more and more variable -- the winter of 2023-24 is a good example, Hill said -- a metric like the new one developed at OSU helps to more objectively quantify the reservoir storage aspect of the globe's snowpacks.

From local to regional scales, he notes, municipal and agricultural users of water need to balance demand with supply, and snow storage dramatically influences the timing of the supply side.

"As we move forward, and as we have moved from the past to the present, the relatively good news is that annual precipitation amounts tend to not change that dramatically," he said. "However, changing temperatures greatly influence snow storage and therefore the timing of water availability."

Read more at Science Daily

Nanodevices can produce energy from evaporating tap or seawater

Evaporation is a natural process so ubiquitous that most of us take it for granted. In fact, roughly half of the solar energy that reaches the earth drives evaporative processes. Since 2017, researchers have been working to harness the energy potential of evaporation via the hydrovoltaic (HV) effect, which allows electricity to be harvested when fluid is passed over the charged surface of a nanoscale device. Evaporation establishes a continuous flow within nanochannels inside these devices, which act as passive pumping mechanisms. This effect is also seen in the microcapillaries of plants, where water transport occurs thanks to a combination of capillary pressure and natural evaporation.

Although hydrovoltaic devices currently exist, there is very little functional understanding of the conditions and physical phenomena that govern HV energy production at the nanoscale. It's an information gap that Giulia Tagliabue, head of the Laboratory of Nanoscience for Energy Technology (LNET) in the School of Engineering, and PhD student Tarique Anwar wanted to fill. They leveraged a combination of experiments and multiphysics modelling to characterize fluid flows, ion flows, and electrostatic effects due to solid-liquid interactions, with the goal of optimizing HV devices.

"Thanks to our novel, highly controlled platform, this is the first study that quantifies these hydrovoltaic phenomena by highlighting the significance of various interfacial interactions. But in the process, we also made a major finding: that hydrovoltaic devices can operate over a wide range of salinities, contradicting prior understanding that highly purified water was required for best performance," says Tagliabue.

The LNET study has recently been published in the Cell Press journal Device.

A revealing multiphysics model

The researchers' device represents the first hydrovoltaic application of a technique called nanosphere colloidal lithography, which allowed them to create a hexagonal network of precisely spaced silicon nanopillars. The spaces between the nanopillars created the perfect channels for evaporating fluid samples, and could be finely tuned to better understand the effects of fluid confinement and the solid/liquid contact area.

"In most fluidic systems containing saline solutions, you have an equal number of positive and negative ions. However, when you confine the liquid to a nanochannel, only ions with a polarity opposite to that of the surface charge will remain," Anwar explains. "This means that if you allow liquid to flow through the nanochannel, you will generate current and voltages."

"This goes back to our major finding that the chemical equilibrium for the surface charge of the nanodevice can be exploited to extend the operation of hydrovoltaic devices across the salinity scale," adds Tagliabue. "Indeed, as the fluid ion concentration increases, so does the surface charge of the nanodevice. As a result, we can use larger fluid channels while working with higher-concentration fluids. This makes it easier to fabricate devices for use with tap or seawater, as opposed to only purified water."

Water, water everywhere

Because evaporation can occur continuously over a wide range of temperatures and humidities -- and even at night -- there are many exciting potential applications for more efficient HV devices. The researchers hope to explore this potential with the support of a Swiss National Science Foundation Starting Grant, which aims to develop "a completely new paradigm for waste-heat recovery and renewable energy generation at large and small scales," including a prototype module under real-world conditions on Lake Geneva.

And because HV devices could theoretically be operated anywhere there is liquid -- or even moisture, like sweat -- they could also be used to power sensors for connected devices, from smart TVs to health and fitness wearables. With the LNET's expertise in light energy harvesting and storage systems, Tagliabue is also keen to see how light and photothermal effects could be used to control surface charges and evaporation rates in HV systems.

Finally, the researchers also see important synergies between HV systems and clean water generation.

Read more at Science Daily

Astronomers reveal a new link between water and planet formation

Researchers have found water vapour in the disc around a young star exactly where planets may be forming. Water is a key ingredient for life on Earth, and is also thought to play a significant role in planet formation. Yet, until now, we had never been able to map how water is distributed in a stable, cool disc -- the type of disc that offers the most favourable conditions for planets to form around stars. The new findings were made possible thanks to the Atacama Large Millimeter/submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner.

"I had never imagined that we could capture an image of oceans of water vapour in the same region where a planet is likely forming," says Stefano Facchini, an astronomer at the University of Milan, Italy, who led the study published today in Nature Astronomy. The observations reveal at least three times as much water as in all of Earth's oceans in the inner disc of the young Sun-like star HL Tauri, located 450 light-years away from Earth in the constellation Taurus.

"It is truly remarkable that we can not only detect but also capture detailed images and spatially resolve water vapour at a distance of 450 light-years from us ," adds co-author Leonardo Testi, an astronomer at the University of Bologna, Italy. The 'spatially resolved' observations with ALMA allow astronomers to determine the distribution of water in different regions of the disc. "Taking part in such an important discovery in the iconic HL Tauri disc was beyond what I had ever expected for my first research experience in astronomy," adds Mathieu Vander Donckt from the University of Liege, Belgium, who was a master's student when he participated in the research.

A significant amount of water was found in the region where a known gap in the HL Tauri disc exists. Ring-shaped gaps are carved out in gas- and dust-rich discs by orbiting young planet-like bodies as they gather up material and grow. "Our recent images reveal a substantial quantity of water vapour at a range of distances from the star that include a gap where a planet could potentially be forming at the present time," says Facchini. This suggests that this water vapour could affect the chemical composition of planets forming in those regions.

Observing water with a ground-based telescope is no mean feat as the abundant water vapour in Earth's atmosphere degrades the astronomical signals. ALMA, operated by ESO together with its international partners, is an array of telescopes in the Chilean Atacama Desert at about 5000 metres elevation that was built in a high and dry environment specifically to minimise this degradation, providing exceptional observing conditions. "To date, ALMA is the only facility able to spatially resolve water in a cool planet-forming disc," says co-author Wouter Vlemmings, a professor at the Chalmers University of Technology in Sweden.*

"It is truly exciting to directly witness, in a picture, water molecules being released from icy dust particles," says Elizabeth Humphreys, an astronomer at ESO who also participated in the study. The dust grains that make up a disc are the seeds of planet formation, colliding and clumping into ever larger bodies orbiting the star. Astronomers believe that where it is cold enough for water to freeze onto dust particles, things stick together more efficiently -- an ideal spot for planet formation. "Our results show how the presence of water may influence the development of a planetary system, just like it did some 4.5 billion years ago in our own Solar System," Facchini adds.

With upgrades happening at ALMA and ESO's Extremely Large Telescope (ELT) coming online within the decade, planet formation and the role water plays in it will become clearer than ever. In particular METIS, the Mid-infrared ELT Imager and Spectrograph, will give astronomers unrivalled views of the inner regions of planet-forming discs, where planets like Earth form.

Read more at Science Daily

Three years later, search for life on Mars continues

In the three years since NASA's Perseverance rover touched down on Mars, the NASA science team has made the daily task of investigating the red planet seem almost mundane.

The rover and its helicopter sidekick Ingenuity have captured stunning images of Mars and collected 23 unique rock core samples along 17 miles of an ancient river delta.

One science team member, University of Cincinnati Associate Professor Andy Czaja, said he sometimes has to remind himself that the project is anything but ordinary.

"This is so cool. I'm exploring another planet," he said.

Czaja teaches in the Department of Geosciences in UC's College of Arts and Sciences. He is a paleobiologist and astrobiologist helping NASA look for evidence of ancient life on Mars using a rover outfitted with custom geoscience and imaging tools with three of his UC graduate students, Andrea Corpolongo, Brianna Orrill and Sam Hall.

Three years into the mission, the rover has performed like a champ, he said.

"Perseverance has excelled. It's been fantastic. It has such capable instrumentation for doing the geology work. It's able to explore distant objects with its zoom lens cameras and can focus on tiny objects at incredible resolution," Czaja said.

Along the way, the mission has recorded a number of firsts: first powered flight, first recorded sounds of Mars, the longest autonomous drive (nearly a half-mile) and new discoveries about the planet's geology, atmosphere and climate.

Czaja was part of the NASA team that decided where on Mars to land the rover. And he remained on the science team that would pore over its daily data and discoveries to decide what the rover should do next.

Among the new discoveries was finding primary igneous rocks in Jezero Crater. These rocks are the hardened result of liquid magma. They offer scientists promising clues about refining the known age of the planet.

Scientists suspect Mars once had long-lived rivers, lakes and streams. Today, water on Mars is found in ice at the poles and trapped below the Martian surface.

Czaja and his student Corpolongo were co-lead authors of a paper published in the Journal of Geophysical Research, Planets that revealed that Mars also may have had hydrothermal systems based on the hydrated magnesium sulfate the rover identified in the volcanic rocks.

"When those rocks cool off and fracture, they become a habitable environment for life," Czaja said.

Corpolongo also led a similar research paper in the same journal co-authored by Czaja detailing the results of the rover's analysis of samples using the SHERLOC deep ultraviolet Raman and fluorescence instrument. Both papers featured contributions from dozens of their fellow NASA researchers on the project.

Samples collected by the rover may finally answer the question about whether we are alone in the universe.

"We have not found any definitive evidence of life in these deposits yet. But if there were fossil microorganisms trapped in the rocks, they would be too small to see with the rover," Czaja said.

Czaja is hopeful funding will be approved for the anticipated Mars Sample Return mission to retrieve the hermetically sealed titanium tubes scientists have spent three years filling with interesting rock cores.

"These hydrated minerals trap water within themselves and record the history of how and when they formed," the study said. "Returning samples of these minerals to Earth would allow researchers to explore the history of Mars' water and climate and possibly evidence of ancient life with the most sensitive instruments possible."

But that was just the beginning. Perseverance began its deliberate exploration from the floor of the crater to the front of the delta, formed by an ancient river or drainage channel where it encountered sedimentary rocks that often contain trapped minerals and another avenue for evidence of ancient life.

And last year the rover made it to the crater's margin in what used to be an enormous lake where it is exploring deposits of magnesium carbonate, which can form geologically or biologically from bacteria.

Czaja said the decision to send Perseverance to Jezero Crater appears to be paying off.

"Absolutely. There were other places we could have gone that might have been just as good," he said. "You won't know until you explore them all. But Jezero was picked for good reason and it has been completely justified."

The helicopter Ingenuity's flying days appear to be over after it sustained rotor damage in January after landing on its 72nd flight. But Perseverance is still going strong. It still has 15 sample tubes at its disposal to capture additional interesting geologic specimens.

Next the rover will make its way out of Jezero Crater to explore the wider area. Czaja said they are likely to find rocks dating back 4 billion years or more. And Mars could harbor stromatolites or rocks that contain evidence of ancient layered mats of bacteria visible to the naked eye. On Earth, these rocks are sometimes found in extreme environments such as geyser basins.

Read more at Science Daily

Little groundwater recharge in ancient Mars aquifer, according to new models

Mars was once a wet world. The geological record of the Red Planet shows evidence for water flowing on the surface -- from river deltas to valleys carved by massive flash floods.

But a new study shows that no matter how much rainfall fell on the surface of ancient Mars, very little of it seeped into an aquifer in the planet's southern highlands.

A graduate student at The University of Texas at Austin made the discovery by modeling groundwater recharge dynamics for the aquifer using a range of methods -- from computer models to simple back-of-the-envelope calculations.

No matter the degree of complexity, the results converged on the same answer -- a miniscule .03 millimeters of groundwater recharge per year on average.

That means that wherever rain fell in the model, only an average of .03 millimeters per year could have entered the aquifer and still produced the landforms remaining on the planet today.

For comparison, the annual rate of groundwater recharge for the Trinity and Edwards-Trinity Plateau aquifers that provide water to San Antonio generally ranges from 2.5 to 50 millimeters per year, or about 80 to 1,600 times the Martian aquifer recharge rate calculated by the researchers.

There are a variety of potential reasons for such low groundwater flow rates, said lead author Eric Hiatt, a doctoral student at the Jackson School of Geosciences.

When it rained, the water may have mostly washed across the Martian landscape as runoff.

Or it may have just not rained very much at all.

These findings can help scientists constrain the climatic conditions capable of producing rainfall on early Mars.

They also suggest a very different water regime on the Red Planet than what exists on Earth today.

"The fact that the groundwater isn't as big of a process could mean that other things are," Hiatt said.

"It might magnify the importance of runoff, or it could mean that it just didn't rain as much on Mars. But it's just fundamentally different from how we think about [water] on Earth."

The results were published in the journal Icarus. The paper's co-authors are Mohammad Afzal Shadab, a doctoral student at the Jackson School and faculty members Sean Gulick, Timothy Goudge and Marc Hesse.

The models used in the study work by simulating groundwater flow in a "steady state" environment where inflow and outflow of water into the aquifer is balanced.

Scientists then changed the parameters affecting the flow -- for example, where rain falls or the average porosity of the rock -- and observed what other variables would have to change to maintain the steady state and how plausible those charges are.

While other researchers have simulated groundwater flow on Mars using similar techniques, this model is the first to incorporate the influence of the oceans that existed on the surface of Mars more than three billion years ago in the Hellas, Argyre, and Borealis basins.

The study also incorporates modern topographical data collected by satellites.

The modern landscape, Hiatt said, still preserves one of the planet's oldest and most influential topographical features -- an extreme difference in elevation between the northern hemisphere -- the lowlands -- and the southern hemisphere -- the highlands -- known as the "great dichotomy." The dichotomy preserves signs of past groundwater upwelling in which groundwater rose up from the aquifer to the surface.

The researchers used geological markers of these past upwelling events to evaluate different model outputs.

Across different models, the researchers found the mean groundwater recharge rate of .03 millimeters per year to match most closely with what's known about the geologic record.

The research isn't just about understanding the Red Planet's past.

It has implications for future Mars exploration too. Understanding groundwater flow can help inform where to find water today, Hiatt said.

Whether you're looking for signs of ancient life, trying to sustain human explorers, or making rocket fuel to get back home to Earth, it's essential to know where the water would most likely be.

Read more at Science Daily

Decline in microbial genetic richness in the western Arctic Ocean

The Arctic region is experiencing climate change at a much faster rate than the rest of the world. Melting ice sheets, runoff from thawing permafrost and other factors are rapidly changing the composition of the Arctic Ocean's water. And that change is being experienced all the way down to the microbial level.

In a Concordia-led study published in the journal ISME Communications, researchers analyzed archival samples of bacteria and archaea populations taken from the Beaufort Sea, bordering northwest Canada and Alaska.

The samples were collected between 2004 and 2012, a period that included two years -- 2007 and 2012 -- in which the sea ice coverage was historically low.

The researchers looked at samples taken from three levels of water: the summer mixed layer, the upper Arctic water below it and the Pacific-origin water at the deepest level.

The study examined the microbes' genetic composition using bioinformatics and statistical analysis across the nine-year time span.

Using this data, the researchers were able to see how changing environmental conditions were influencing the organisms' structure and function.

The researchers found subtle but statistically significant changes in the communities they studied.

"We observed a general overall loss in diversity of species across all the different water masses," says David Walsh, a professor in the Department of Biology and the paper's corresponding author.

"We also saw changes in the composition of the microbial community, meaning there were different species after the 2007 sea ice minimum than before."

However, the periods of population richness decline changed between the ocean's layers of water.

Sudden decline in the fresher summer mixed water level, between 3-9 meters deep, was observed in 2005-2007.

The upper Arctic water, between 16-78 metres, saw declines in 2010-2012, while the deeper Pacific water layer, between 49-154 meters, experienced a two-step decline -- once between 2005-2007 and again between 2010-2012.

Small beginnings

The researchers are taking care not to overemphasize the results of their findings, saying the changes, while significant, remain slight.

But with the summer Arctic ice cover shrinking steadily year over year, the data does hint at possible trends that may be visible in upcoming population studies in more recent years.

"With the warming and freshening of the Arctic Ocean comes a decrease of nutrients that are important for photosynthesis, which produces the organic matter that serves as energy and carbon sources for the marine food web," Walsh explains.

"This shift risks strengthening what is known as the microbial loop, in which the energy and carbon that would normally go into higher trophic levels -- meaning zooplankton and then fish -- is rapidly recycled by microorganisms. This ecosystem is already dominated by microbial processes, which will only get stronger as this system continues."

"This study provides us with a baseline idea of what is happening in the Arctic," says co-author Arthi Ramachandran, PhD 23. "The Arctic is warming four times faster than the rest of the world, which makes it a fascinating ecosystem to study. The oceans are all interconnected, and the physical barriers of these oceans are becoming much less defined."

Looking into the ocean's warmer, fresher future

The researchers are now planning a metagenomic study that extends the time series to cover periods of even more intense sea ice minima.

They hope to fully sequence the organisms' genomes to further understand the microbial communities' diversity and function in the environment.

Read more at Science Daily

Mimas' surprise: Tiny moon of Saturn holds young ocean beneath icy shell

Hidden beneath the heavily cratered surface of Mimas, one of Saturn's smallest moons, lies a secret: a global ocean of liquid water. This astonishing discovery, led by Dr. Valéry Lainey of the Observatoire de Paris-PSL and published in the journal Nature, reveals a "young" ocean formed just 5 to 15 million years ago, making Mimas a prime target for studying the origins of life in our Solar System.

"Mimas is a small moon, only about 400 kilometers in diameter, and its heavily cratered surface gave no hint of the hidden ocean beneath," says Dr Nick Cooper, a co-author of the study and Honorary Research Fellow in the Astronomy Unit of the School of Physical and Chemical Sciences at Queen Mary University of London.

"This discovery adds Mimas to an exclusive club of moons with internal oceans, including Enceladus and Europa, but with a unique difference: its ocean is remarkably young, estimated to be only 5 to 15 million years old."

This young age, determined through detailed analysis of Mimas's tidal interactions with Saturn, suggests the ocean formed recently, based on the discovery of an unexpected irregularity in its orbit.

As a result, Mimas provides a unique window into the early stages of ocean formation and the potential for life to emerge.

"The existence of a recently formed liquid water ocean makes Mimas a prime candidate for study, for researchers investigating the origin of life," explains Dr Cooper.

The discovery was made possible by analysing data from NASA's Cassini spacecraft, which meticulously studied Saturn and its moons for over a decade.

By closely examining the subtle changes in Mimas's orbit, the researchers were able to infer the presence of a hidden ocean and estimate its size and depth.

Dr Cooper continues: "This has been a great team effort, with colleagues from five different institutions and three different countries coming together under the leadership of Dr Valéry Lainey to unlock another fascinating and unexpected feature of the Saturn system, using data from the Cassini mission."

Read more at Science Daily

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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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

Rocky planets can form in extreme environments

An international team of astronomers has used NASA's James Webb Space Telescope to provide the first observation of water and other molecules in the highly irradiated inner, rocky-planet-forming regions of a disk in one of the most extreme environments in our galaxy. These results suggest that the conditions for terrestrial planet formation can occur in a possible broader range of environments than previously thought.

These are the first results from the eXtreme Ultraviolet Environments (XUE) James Webb Space Telescope program, which focuses on the characterization of planet-forming disks (vast, spinning clouds of gas, dust, and chunks of rock where planets form and evolve) in massive star-forming regions.

These regions are likely representative of the environment in which most planetary systems formed.

Understanding the impact of environment on planet formation is important for scientists to gain insights into the diversity of the different types of exoplanets.

The XUE program targets a total of 15 disks in three areas of the Lobster Nebula (also known as NGC 6357), a large emission nebula roughly 5,500 light-years away from Earth in the constellation Scorpius.

The Lobster Nebula is one of the youngest and closest massive star-formation complexes, and is host to some of the most massive stars in our galaxy.

Massive stars are hotter, and therefore emit more ultraviolet (UV) radiation.

This can disperse the gas, making the expected disk lifetime as short as a million years.

Thanks to Webb, astronomers can now study the effect of UV radiation on the inner rocky-planet forming regions of protoplanetary disks around stars like our Sun.

"Webb is the only telescope with the spatial resolution and sensitivity to study planet-forming disks in massive star-forming regions," said team lead María Claudia Ramírez-Tannus of the Max Planck Institute for Astronomy in Germany.

Astronomers aim to characterize the physical properties and chemical composition of the rocky-planet-forming regions of disks in the Lobster Nebula using the Medium Resolution Spectrometer on Webb's Mid-Infrared Instrument (MIRI). This first result focuses on the protoplanetary disk termed XUE 1, which is located in the star cluster Pismis 24.

"Only the MIRI wavelength range and spectral resolution allow us to probe the molecular inventory and physical conditions of the warm gas and dust where rocky planets form," added team member Arjan Bik of Stockholm University in Sweden.

Due to its location near several massive stars in NGC 6357, scientists expect XUE 1 to have been constantly exposed to high amounts of ultraviolet radiation throughout its life.

However, in this extreme environment the team still detected a range of molecules that are the building blocks for rocky planets.

"We find that the inner disk around XUE 1 is remarkably similar to those in nearby star-forming regions," said team member Rens Waters of Radboud University in the Netherlands.

"We've detected water and other molecules like carbon monoxide, carbon dioxide, hydrogen cyanide, and acetylene. However, the emission found was weaker than some models predicted. This might imply a small outer disk radius."

"We were surprised and excited because this is the first time that these molecules have been detected under these extreme conditions," added Lars Cuijpers of Radboud University.

The team also found small, partially crystalline silicate dust at the disk's surface.

This is considered to be the building blocks of rocky planets.

These results are good news for rocky planet formation, as the science team finds that the conditions in the inner disk resemble those found in the well-studied disks located in nearby star-forming regions, where only low-mass stars form.

This suggests that rocky planets can form in a much broader range of environments than previously believed.

The team notes that the remaining observations from the XUE program are crucial to establish the commonality of these conditions.

Read more at Science Daily

Heat tolerant coral may trade fast growth for resilience

Algae living within the soft tissue of coral supply much of the energy needed by their hosts, and some symbiotic algae help coral withstand warmer water better than others. In a recently published study led by the University of Hawai'i at Manoa, researchers found that there was a tradeoff for corals dominated by the thermally sensitive algae -- they have higher growth, but only in cooler water.

"As the ocean continues to warm, understanding how symbionts and environmental factors affect coral growth and health will help predict reef futures and inform conservation interventions where coral stocks are selected for specific traits or symbionts," said Shayle Matsuda, a doctoral student at the Hawai'i Institute of Marine Biology in the UH Mānoa School of Ocean and Earth Science and Technology at the time of the research.

The study was co-led by Matsuda, now a postdoctoral fellow at the Shedd Aquarium, and Mariah Opalek, who conducted the experiment for her undergraduate thesis at UH Mānoa. The research team investigated whether rice corals hosting symbiotic algae that can tolerate warmer water may grow more slowly, which could impact survivorship and competition for space on the reef, compared to coral hosting symbionts that are more susceptible to bleaching when ocean waters warm.

Over a two-month study period, the researchers measured the growth of rice corals dominated by heat tolerant or heat sensitive symbiotic algae. Additionally, they tested growth across decreasing light levels to see if the tradeoff between growth and tolerance to warm water would be affected by light, which is a major driver of the distribution of these symbionts in Kāneʻohe Bay, Hawai'i.

"This research shows us the complexity of coral growth on a reef," said Opalek, who is now a grant support assistant at Kaua'i Community. "A coral's competitive advantage could be lost in a matter of a few degrees depending on what type of symbiont they associate with."

During the first month, when water temperatures were warmer, the symbiont present did not affect growth. However, over the cooler second month, corals with heat sensitive algae grew up to 77% faster than corals dominated by heat tolerant algae, and this growth advantage increased in higher light treatments, which correlates to shallower depths on a reef.

Read more at Science Daily