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There’s very little scientific debate about the existence of surface water on Mars in its past. The evidence at this point is overwhelming. Orbiter images clearly show river channels and deltas, and rovers have found ample minerals that only form in the presence of water. Now the scientific debate has moved on. Scientists are trying to learn the extent of Martian surface water, both on the planet’s surface and through time.

NASA’s Mars Reconnaissance Orbiter (MRO) is a prolific purveyor of images of Mars’ surface. One of its most well-known image shows Jezero Crater, the landing site of the Mars Perseverance rover. Jezero Crater is an ancient paleolake filled by an ancient river that created a delta of sediments. The orbiter also identified clays and carbonate salts, minerals that were altered by water in the planet’s past.

This image of Jezero Crater is one of the MRO’s most well-known images. It shows clear evidence of flowing water. The colours map the location of different minerals, including water-altered clays and carbonate salts. Image Credit: NASA/ JPL-Caltech/ MSSS/ JHU-APL.

There are two schools of thought around Mars’ watery past. One says that water was stable on the Martian surface for long periods of time, while the other states that the water channels were carved during geologically brief periods of time when climate shifts caused ice sheets to melt. Call the first one the ‘warm and wet’ theory and the second one the ‘cold and dry’ theory. Both theories are well developed, and make predictions about what scientists will find when they dig deeper.

Some research into Noachis Terra supports the idea that water features there were carved by ice-related processes during short-lived periods of wetness, the cold and dry theory. This 2016 paper illustrates that point of view. “Our studied valleys’ association with ice-rich material and abundant evidence for erosion caused by downslope flow of ice-rich material are consistent with a cold, wet Mars hypothesis where accumulation, flow, and melting of ice have been dominant factors in eroding crater valleys,” those researchers concluded.

Not all regions of Mars have been studied equally, and the Noachis Terra is not as well-studied as some other regions. The ‘warm and wet’ climate theory predicts that Noachis Terra would’ve had high levels of precipitation. However, there’s an overall lack of Valley Networks (VNs) in the region. Valley Networks are similar to Earth’s river drainage basins and are compelling evidence of Mars’ watery past.

This map of Mars shows important surface features, as well as all of the planet’s surface regions. Noachis Terra is a southern highland region of heavily cratered ancient terrain. Image Credit: By Jim Secosky modified NASA image. – http://planetarynames.wr.usgs.gov/images/mola_regional_boundaries.pdf, Public Domain,

New research presented at the Royal Astronomical Society’s National Astronomy Meeting presented a different sort of evidence to support the high levels of precipitation predicted in Noachis Terra by the warm and wet theory. It’s titled “The Fluvial History of Noachis Terra, Mars,” and the lead researcher is Adam Losekoot. Losekoot is a PhD student at the Open University, a public research university in the UK.

“Studying Mars, particularly an underexplored region like Noachis Terra, is really exciting because it’s an environment which has been largely unchanged for billions of years. It’s a time capsule that records fundamental geological processes in a way that just isn’t possible here on Earth,” Losekoot said in a press release.

The evidence Losekoot and his fellow researchers uncovered is in the form of Fluvial Sinuous Ridges.

“Noachis Terra, in Mars’ southern highlands, is a region where ‘warm, wet’ climate models predict high rates of precipitation, but is poorly incised by VNs,” Losekoot explained. “We searched instead for Fluvial Sinuous Ridges (FSRs, aka inverted channels) here as they provide alternate evidence to VNs for stable surface water.”

FSRs are winding, elevated features left behind from Mars’ watery past. They form when water flows across the surface carrying sediment with it. The sediment deposits become harder than the rock in the surrounding terrain due to compaction and mineral precipitation. When Mars’ water disappeared, aeolian erosion ate away at the softer, surrounding rock, leaving the elevated FSRs behind.

To find the FSRs in Noachis Terra, Losekoot and his co-researchers turned to NASA’s MRO. No other mission has done more to reveal Mars’ past than the MRO. They used data from its HiRISE and other instruments, as well as data from the Mars Orbital Laser Altimeter on the Mars Global Surveyor, to identify FSRs.

Losekoot and his co-researchers found 15,000 km of FSRs in Noachis Terra. “We find FSRs to be common across Noachis Terra, with a cumulative length of more than 15,000 km. These are often isolated segments, but some systems are hundreds of km in length,” Losekoot writes.

This HiRISE image shows two branches of an FSR. The river split into two then rejoined outside of the image. The lower branch is heavily eroded and quite spread out, the upper branch is narrower but more clearly preserved. They could’ve had different exposure times or undergone different geological processes. Or they could be from different periods of water activity. There are remnants of an infilling material within the ridge and a meander where the branch turns back towards the lower trunk. The mesa in between the branches could be a crater that was filled with the same sediment as the FSR. Image Credit: HiRISE Image: ESP_085519_1585 NASA/JPL/University of Arizona. Licence type: Attribution (CC BY 4.0)

The FSRs are broadly distributed across Noachis Terra, and some are tens of meters tall. That means the water flowed for a long time.

“The broad distribution of FSRs suggests a broadly distributed source of water,” Losekoot writes. “The most likely candidate is precipitation, suggesting a benign surface environment. For FSRs to have formed mature, interconnected systems, up to tens of meters high, these conditions must also have been relatively long-lived.”

“This suggests that ~3.7 Ga, Noachis Terra experienced warm and wet conditions for a geologically relevant period,” Losekoot explained.

This HiRISE image shows narrow FSR with a pointed pinnacle ridge. The pointed could indicate that this FSR has suffered heavy erosion for a long time until only a narrow peak remained, or it may be that only a narrow part of the original river infill has been preserved. Image Credit: HiRISE Image: ESP_067439_1505 NASA/JPL/University of Arizona. Licence type: Attribution (CC BY 4.0)

The way the FSRs are distributed across Noachis Terra and their extent suggests that precipitation is responsible. They also form large, interconnected systems, which suggests the watery period was long-lived. This work supports the idea that Mars was warm and wet for a long time, rather than just for bursts of time when ice sheets melted.

This MRO CTX image gives an oblique view of part of a system of FSRs in Noachis Terra. It shows river tributaries that were probably active at the same time. The rivers meandered, and there are areas where the river banks burst and deposited fine layers of sediment. At the top of the image is a really clear example of an area where two FSRs intersect with an infilled crater. This is likely where the river flowed into the crater, filling it up and then breaching the other side to continue through the crater and down to the bottom of the image. CTX image: MurrayLab_V01_E020_N-20_Mosaic. Image Credit: NASA/JPL/MSSS/The Murray Lab. Licence type: Attribution (CC BY 4.0)

“Our work is a new piece of evidence that suggests that Mars was once a much more complex and active planet than it is now, which is such an exciting thing to be involved in,” said Losekoot.

Space is cold, and research has shown time and time again that space ice is prevalent throughout the universe. However, despite sharing a similar name to the ice we find in glaciers or even in our freezers here on Earth, new research says that frozen water found on icy planets, comets, and even in the dust that sails through space is very different from the ice you might put your soda over.

For starters, despite looking like a shapeless solid, ice is actually made up of multiple nanoscopic crystals, all of which are only a few billionths of a meter across, if that. So, what makes Earth ice and space ice so different? Well, according to researchers, Earth ice is made up of orderly lattice crystal designs. These all showcase the six-fold symmetry of snowflakes in the underlying structure.

But we’ve long believed that space ice has a different structure. Instead, because of the near-vacuum conditions of space, the water frozen there likely lacked the energy needed to form these orderly lattices. Scientists believed they were most likely made up of random arrangements of crystals. But new research is challenging this perspective.

Instead of being made up entirely of random crystallized structures, the researchers found that in order for the ice they made in their tests to truly resemble that of space ice, they had to give it some structure — roughly 20% of the overall structure. But what is even more intriguing is that when warmed slightly, they found that the crystals retain the structure seen in their original designs.

This suggests that the ice holds onto some of its memory of the past, which could help greatly in future studies of frozen water in space. It could also fundamentally change our understanding of how life came to Earth, something that researchers have long theorized happened as amino acids hitched rides in the frozen water of comets.

But if space ice retains some of the structure of its original design, then the empty places for those acids to grow and live would be even more scarce than they was previously thought to be. Of course, the study is far from definitive, and further research will need to be done to confirm these findings. For now, though, they raise some interesting questions about what we think we know about how the universe and space ice actually works.

A groundbreaking study in the journal Science, has unveiled how deep ocean currents—known as global overturning circulation—play a pivotal role in shaping the diversity and function of microbial life across the South Pacific Ocean. 

This research, led by scientists from J. Craig Venter Institute (JCVI), UC San Diego’s Scripps Institution of Oceanography, and University of California Berkeley offers the most detailed genetic map to date of how microbial communities are structured by the physical movement of ocean water.

Winds and storms only reach to about 500 meters (1,640 feet), about an eighth of the total ocean depth of 4,000 meters (13,125 feet), said study lead author Bethany Kolody, a graduate of Scripps Oceanography who is currently a postdoctoral researcher at Cal. Beyond 500 meters below the surface, currents are driven by differences in water temperature and salinity, which affects its density, forming the global overturning circulation. This circulation acts like a conveyor belt, transporting water—and the microbes within it—across vast distances and depths.

“Until now, it was unclear whether these water masses also served as distinct microbial ecosystems,” said Kolody. “We can now answer that question with a resounding, ‘yes.’”

The research team collected over 300 water samples along a transect from Easter Island in the South Pacific Ocean to Antarctica, spanning the full depth of the ocean. Using advanced metagenomic and metabarcoding techniques, they reconstructed the genomes for more than 300 microbes and identified tens of thousands of additional microbial species using a molecular fingerprinting technique that looks at highly conserved genes—the 16S rRNA gene for prokaryotes (which includes both bacteria and archaea) and the 18S rRNA gene for eukaryotes.

Their findings revealed a striking pattern: microbial diversity increases sharply some 300 meters (1,000 feet) below the ocean surface in a zone they call the “prokaryotic phylocline.” This layer, akin to the pycnocline (a zone of rapid density change), marks a transition from low-diversity surface waters to the rich microbial communities of the deep ocean.

The study, released July 10, identified six distinct microbial “cohorts,” three of which correspond to depths and the other three aligning with major water masses: Antarctic Bottom Water, Upper Circumpolar Deep Water , and ancient Pacific Deep Water. Each cohort harbors unique microbial species and functional genes, shaped by the temperature, pressure, nutrient levels, and age of the water.

For example, the Antarctic Bottom Water cohort includes microbes adapted to cold, high-pressure environments, with genes that help maintain membrane fluidity and resist oxidative stress. In contrast, the ancient water cohort—found in slow circulating water that has not seen the surface in 1,000 or more years—hosts microbes with genes enabling life in low oxygen environments and the breakdown of complex, low-energy carbon compounds.

Beyond taxonomy, the researchers also mapped the functional potential of microbial communities. They identified ten “functional zones” based on the presence of key metabolic genes. These zones correspond to oceanographic features such as upwelling regions, nutrient gradients, and oxygen minimum zones.

Surface zones were rich in genes for light harvesting, iron acquisition, and photoprotection—traits essential for life in the sunlit upper ocean. Deeper zones featured genes for breaking down complex organic molecules, surviving low oxygen, and enduring environmental stress.

Microbes are the engines of the ocean’s carbon cycle. They convert carbon dioxide into organic compounds (carbon fixing), recycle nutrients, and help trap carbon in the deep sea (carbon sequestration). Understanding how their communities are structured by ocean circulation is crucial for predicting how climate change might alter these processes.

“The study provides a baseline for how microbial ecosystems are organized under current ocean conditions,” said Andrew Allen, senior author of the study and a microbial oceanographer at JCVI and Scripps Oceanography. “As climate change impacts global overturning circulation, the distribution and function of these microbial communities could shift, with unknown consequences for global carbon cycling.”

By pairing genomic data with physical and chemical measurements, scientists can build a global, species-resolved atlas of ocean life—essential for understanding and protecting the planet’s largest ecosystem.

“This study is a reminder that life in ocean ecosystems is, in part, governed by fundamental patterns and processes that are unknown to us,” said Allen. “Seeing and understanding them requires that we examine them more sensitively, carefully, and thoroughly. The breakthroughs reported in this study are the result of a truly interdisciplinary effort involving physical oceanographers, biological oceanographers, and genome biologists all working very closely together. Agencies, such as the National Science Foundation, that support basic interdisciplinary ecological research in life and earth sciences, continue to be essential to our ability to understand factors that control the distribution, diversity, metabolism, and evolution of organisms in nature.”

The authors advocate for incorporating molecular sampling into global ocean monitoring programs like GO-SHIP. 

Besides Andrew Allen, Scripps Oceanography researchers affiliated with the study include  Zoltán Füssy, Sarah Purkey and Eric Allen. 

The complete study, “Overturning circulation structures the microbial functional seascape of the South Pacific,” is published in the journal Science. This research was supported by the National Science Foundation, the Simons Foundation, the National Institutes of Health, the Emerson Collective, the Gordon and Betty Moore Foundation, and the Chan Zuckerberg Initiative.

Adapted from JCVI

 

A new device combining ultrasound and advanced imaging to provide crucial information for the safe delivery of drugs into the brain has been developed by University of Queensland researchers.

Dr. Pranesh Padmanabhan from UQ’s School of Biomedical Sciences and Queensland Brain Institute said the device allows real-time observation of individual cells after ultrasound treatment, which is an emerging technology for the delivery of drugs past the blood-brain barrier.

The information learned about how treated cells respond and change could ultimately benefit the treatment of neurodegenerative brain disorders such as Alzheimer’s and Parkinson’s disease.

The blood-brain barrier prevents most drug uptake into the brain.

Insights from this device will help inform ultrasound treatment protocols and establish a balance where uptake of drugs into the brain is effective, yet still safe.”

Dr. Pranesh Padmanabhan from UQ’s School of Biomedical Sciences and Queensland Brain Institute 

The custom-built device will examine sonoporation-based drug delivery.

Sonoporation is an emerging strategy involving ultrasound-based treatment combined with injected ‘microbubbles’.

In this process, sound waves interact with the microbubbles causing them to vibrate and exert force on the blood-brain barrier to create a tiny pore at the cell surface.

Dr. Padmanabhan said the device, developed over 5 years, will allow researchers to identify and map changes in treated cells and observe how they respond and recover.

“This device will enable scientists to understand how ultrasound-based treatments work at the single-molecule and single-cell levels,” he said.

“It has the potential to improve treatment of neurodegenerative diseases, where drugs target specific areas of the brain.

“The goal is really to improve the rate of uptake of drugs into the brain, as currently only about 1-2 per cent of small molecule drugs actually reach it.

“The results could also help inform treatment in other medical fields where sonoporation shows great promise, including cardiology and oncology.”

The research is published in Journal of Controlled Release.