Category: 7. Science

Coral reefs worldwide, including the Great Barrier Reef, have faced severe damage from recent bleaching events caused by rising ocean temperatures. A 2025 study published in Coral Reefs highlights the devastating impact of the 2024 Fourth Global Coral Bleaching Event at Lizard Island, revealing up to 92% coral mortality. Using drone-derived imagery, the research underscores the vulnerability of coral ecosystems to climate change and the urgent need for action to protect marine life.

The Role of Drone Technology in Coral Research

A key factor in the success of this study was the use of drone technology, which enabled researchers to capture high-resolution imagery of coral reefs before, during, and after the bleaching event. The drones, specifically DJI Mini 3 Pro and Autel Evo II models, provided unparalleled precision, allowing researchers to document the extent of coral bleaching and assess coral mortality over large areas. Professor Jane Williamson, one of the senior authors of the study, noted the significant advantage of using drone-derived imagery: “Using drone-derived imagery, we followed the amount of bleached and living coral during and after the bleaching event,” she said. “Use of this technology lets us upscale the effects of the bleaching event over larger areas but still at high precision.”

Drone technology has proven invaluable in providing a comprehensive and accurate assessment of reef conditions, particularly in areas that are difficult to access by traditional means. This ability to monitor large sections of the reef system at a high resolution is crucial for tracking the long-term health of coral ecosystems and identifying the areas most at risk from climate change.

Unprecedented Coral Mortality Rates

The data from the study is both alarming and sobering. Dr. Vincent Raoult, the lead author of the research, highlighted the severity of the bleaching event: “This marks one of the highest coral mortality rates ever documented globally.” The research revealed that coral mortality rates in some areas of Lizard Island surpassed 92%, with certain sections seeing total collapse. The implications of this finding are far-reaching, as Lizard Island has long been considered a resilient part of the Great Barrier Reef. Despite experiencing some environmental challenges in recent years, including cyclones and Crown-of-Thorns starfish outbreaks, the reef had shown signs of recovery in prior years. However, the 2024 bleaching event proved catastrophic, overwhelming the reef’s ability to bounce back.

The mortality rate at Lizard Island is particularly concerning when viewed in the context of lower heat stress compared to other parts of the reef. Dr. Raoult noted, “Despite lower heat stress at Lizard Island compared with other parts of the Great Barrier Reef, the mortality rate is unprecedented.” This underscores the sensitivity of coral ecosystems to even modest increases in ocean temperature. As global warming continues, coral reefs around the world will likely face even greater threats, with the potential for irreversible damage if immediate action is not taken.

The Long-Term Threat to Reef Resilience

The findings from this research are especially concerning given the increasing frequency and intensity of extreme heat events predicted for the near future. Professor Williamson’s statement underscores the urgency of addressing climate change: “Our results are concerning for coral resilience, considering the increasing frequency and intensity of extreme heat events predicted for the near future, with potentially irreversible consequences for reef ecosystems such as those studied in our Great Barrier Reef.”

Coral reefs are vital to marine biodiversity, supporting a wide range of marine species and providing essential ecosystem services such as coastal protection. The loss of coral cover not only affects marine life but also has significant socioeconomic consequences, particularly for communities reliant on coral reefs for tourism and fishing industries. With the increasing severity of climate-induced stressors, coral reefs face a real risk of collapse, and the recovery process could take decades, if not longer.

The research team is now running additional surveys at Lizard Island to track potential recovery over the next several years. These efforts are part of a broader initiative to monitor and protect coral reefs across Australia, including funding from the Australian Museum Lizard Island Critical Grant.

The sea spider, those spindly marine oddities that seem composed almost entirely of legs and claws, just given up their genetic secrets.

An international effort led by the University of Vienna and the University of Wisconsin–Madison has delivered the first chromosome-level genome for Pycnogonum litorale, a species common in North Atlantic tide pools.

Stretching across 57 pseudo-chromosomes and paired with extensive developmental transcriptomes, the assembly offers an unprecedented look at how an arthropod can evolve such an extreme body plan. This includes a nearly vanishing abdomen and internal organs that spill far into its limbs.

Mapping the sea spider genome

To achieve a genome this contiguous, the team combined long-read sequencing with Hi-C proximity data. Long reads captured tens of thousands of DNA bases at a stretch. This helped bridge the repetitive regions that routinely break short-read assemblies.

Hi-C, which measures how DNA folds inside the nucleus, then provided a “scaffolding” map that placed those long contigs into chromosomal order.

“The genomes of many non-canonical laboratory organisms are challenging to assemble, and Pycnogonum is no exception,” said first author Nikolaos Papadopoulos, a zoologist at the University of Vienna.

“Only the combination of modern high-throughput data sources made a high-quality genome possible. This can now serve as a stepping stone for further research.”

Because sea spiders are not standard lab animals, researchers collected specimens by hand, often prying them from kelp during low tide. They then rushed them back to the lab for nucleic acid extraction.

The payoff is a reference genome that joins spider, scorpion, mite, and horseshoe crab assemblies on public databases. Yet it lacks the duplications that mark other arachnid genomes, making it a vital baseline for evolutionary comparisons.

Vanished gene, vanished abdomen

The analysis focused on Hox genes, key developmental regulators shared by animals from fruit flies to humans. One gene turned up missing: abdominal-A (abd-A).

In most arthropods, abd-A helps establish the rear-body segments that carry guts and reproductive organs. Sea spiders, with their virtually absent abdomens, appear to have dispensed with both the physical structure and its genetic architect.

“In arthropods, Hox genes play a central role in the correct specification of the different body segments, explained co-author Andreas Wanninger, who co-led the Vienna team. “In many other animal groups they are essential ‘master controllers’ during body plan development.”

The disappearance of abd-A mirrors patterns seen in mites and barnacles, two other arthropod groups that have independently shrunk or lost their hind segments.

Sea spiders skipped genome doubling

Spiders and scorpions carry extra copies of almost every gene, relics of an ancient whole-genome duplication that likely fueled innovations such as silk glands and complex venom cocktails.

P. litorale shows no sign of that event. Because sea spiders sit at the very base of the chelicerate lineage, the simplest explanation is that the duplication occurred later. It likely arose within the spider-scorpion branch, rather than in the common ancestor of all chelicerates.

That finding reshapes timelines for when gene families expanded and may help researchers pinpoint which duplications underlie spider-specific traits.

Beyond raw sequence, the consortium generated RNA profiles from embryos and juveniles, capturing when each gene flicks on and off as new body segments form.

Those developmental datasets make the sea spider a promising model for studies of ancestral arthropod development, limb regeneration, and physiological resilience in cold, nutrient-poor seas.

Georg Brenneis, an expert in arthropod development at the University of Vienna, is a senior author of the study.

“From an evolutionary developmental perspective, sea spiders are very interesting: their mode of development may be ancestral for arthropods, but at the same time they boast multiple body plan innovations unique to themselves. Beyond this, they also possess remarkable regenerative abilities.”

“Now that we have the genome and comprehensive datasets on gene activities during development, we can systematically study all of these aspects on the molecular level,” he said.

Editing limbs and trunk

With CRISPR editing becoming feasible in marine invertebrates, investigators can now ask how the remaining sea spider Hox genes choreograph eight elongated walking legs and a tubular trunk. They can also explore how the animals quickly regrow lost appendages.

Comparative physiologists might search the genome for stress-response genes that let sea spiders thrive in icy fjords, while ecological genomics teams could examine how gene flow operates across their wide geographic ranges.

Tracing ancient sea spider cousins

Without the duplication, shared sea spider genes likely existed as single copies in the last common chelicerate ancestor.

Aligning those sequences will clarify where new venom toxins arose, when silk machinery evolved, and how immune genes diversified.

The genome also lets scientists investigate regulatory DNA – enhancers, promoters, and non-coding RNAs. These elements rewired a conventional arthropod blueprint into the minimalist sea spider form.

Expanding the genomic catalog

The authors envision expanding the catalog to additional sea spider species to test whether abd-A loss is universal. They also aim to map gains and losses of other developmental genes across the group’s 1,300 known species.

Such work could uncover genetic shortcuts to extreme morphological change – insights that extend far beyond any single marine arthropod.

For now, the P. litorale genome stands as a milestone: the first high-quality reference for the world’s most enigmatic chelicerates. It’s also a reminder that even life’s strangest branches follow molecular rules that genomics can finally reveal.

The study is published in the journal BMC Biology.

Image Credit: Richard Lord/ CC BY-NC-SA 4.0

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Why is Mars barren and uninhabitable, while life has always thrived here on our relatively similar planet Earth?

A discovery made by a NASA rover has offered a clue for this mystery, new research said Wednesday, suggesting that while rivers once sporadically flowed on Mars, it was doomed to mostly be a desert planet.

Mars is thought to currently have all the necessary ingredients for life except for perhaps the most important one: liquid water.

However the red surface is carved out by ancient rivers and lakes, showing that water once flowed on our nearest neighbour.

Related: Extremely Weird Rock Found on Mars Looks Like Nothing Else Around It

There are currently several rovers searching Mars for signs of life that could have existed back in those more habitable times, millions of years ago.

Earlier this year, NASA’s Curiosity rover discovered a missing piece in this puzzle: rocks that are rich in carbonate minerals.

These “carbonates” – such as limestone on Earth – act as a sponge for carbon dioxide, pulling it in from the atmosphere and trapping it in rock.

A new study, published in the journal Nature, modelled exactly how the existence of these rocks could change our understanding of Mars’s past.

Brief ‘oases’

Lead study author Edwin Kite, a planetary scientist at the University of Chicago and a member of the Curiosity team, told AFP it appeared there were “blips of habitability in some times and places” on Mars.

But these “oases” were the exception rather than the rule.

On Earth, carbon dioxide in the atmosphere warms the planet. Over long timescales, the carbon becomes trapped in rocks such as carbonates.

Then volcanic eruptions spew the gas back into the atmosphere, creating a well-balanced climate cycle supportive of consistently running water.

However Mars has a “feeble” rate of volcanic outgassing compared to Earth, Kite said. This throws off the balance, leaving Mars much colder and less hospitable.

According to the modelling research, the brief periods of liquid water on Mars were followed by 100 million years of barren desert – a long time for anything to survive.

It is still possible that there are pockets of liquid water deep underground on Mars we have not yet found, Kite said.

NASA’s Perseverance Rover, which landed on an ancient Martian delta in 2021, has also found signs of carbonates at the edge of dried-up lake, he added.

Next, the scientists hope to discover more evidence of carbonates.

Kite said the best proof would be returning rock samples from the Martian surface back to Earth – both the United States and China are racing to do this in the next decade.

Are we alone?

Ultimately, scientists are searching for an answer to one of the great questions: how common are planets like Earth that can harbour life?

Astronomers have discovered nearly 6,000 planets beyond our Solar System since the early 1990s.

But only for Mars and Earth can scientists study rocks which allow them to understand the planet’s past, Kite said.

If we do determine that Mars never hosted even tiny micro-organisms during its watery times, that would indicate it is difficult to kick-start life across the universe.

But if we discover proof of ancient life, that would “basically be telling us the origin of life is easy on a planetary scale,” Kite said.

© Agence France-Presse

This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.

Picture this: a small audience is quietly ushered into a darkened room. They gasp in awe, as a brilliant night sky shines above. They wonder – as many after them will do – what trickery has made the roof above their heads disappear?

The ALMA Observatory, one of the world’s most advanced astronomical facilities, has uncovered unprecedented details about the earliest galaxies formed in the universe. The results of the CRISTAL survey, an ambitious research project that spans across several years, showcase the power of the Atacama Large Millimeter/submillimeter Array (ALMA) to explore the early cosmos. By focusing on galaxies just one billion years after the Big Bang, the survey has provided detailed maps of cold gas, dust, and stellar formations, offering a new perspective on how galaxies evolved during their infancy.

The groundbreaking study is not the first to showcase ALMA’s immense capabilities. Previously, ALMA helped reveal key information about the formation of galaxies, tracing star formation in the distant universe. However, the CRISTAL survey takes it a step further, presenting a complete view of galactic ecosystems. These findings, when combined with earlier works, provide a more thorough understanding of galactic birth and evolution. As scientists continue to examine how our universe’s galaxies formed, these recent discoveries by ALMA play a crucial role in reshaping our understanding of cosmic history.

A Closer Look at Early Galaxies: The CRISTAL Survey

The CRISTAL survey was designed to observe galaxies from a period known as the “cosmic dawn,” roughly one billion years after the Big Bang. Using the unique capabilities of ALMA, the survey reveals crucial aspects of early galactic structures, most notably the cold gas and dust that serve as the building blocks for stars. By focusing on [CII] emission, a type of light emitted by ionized carbon atoms, researchers could map the internal structures of 39 galaxies. These galaxies were selected to represent the typical star-forming populations of the early universe, providing essential clues into how galaxies like the Milky Way took shape.

“Thanks to ALMA’s unique sensitivity and resolution, we can resolve the internal structure of these early galaxies in ways never possible before,” said Rodrigo Herrera-Camus, the principal investigator of the CRISTAL survey. “CRISTAL is showing us how the first galactic disks formed, how stars emerged in giant clumps, and how gas shaped the galaxies we see today.” This breakthrough allows scientists to move beyond basic observations of distant galaxies and explore their complex structures, offering insights into their star formation processes and overall evolution.

The Formation of Galactic Disks and Clumpy Star Formation

One of the most significant findings of the CRISTAL survey is the discovery of large-scale, clumpy star formation in the early galaxies. These stars formed in clusters, with each spanning thousands of light-years. Such findings not only challenge previous assumptions about how early stars formed but also reveal the chaotic and energetic environment in which these galaxies took shape. As galaxies developed, they formed dense clumps of gas and dust where stars emerged. These clumps provided the fuel for star formation, allowing galaxies to grow and evolve at rapid rates during their infancy.

“What’s exciting about CRISTAL is that we are seeing early galaxies not just as points of light, but as complex ecosystems,” said Loreto Barcos-Muñoz, co-author of the study and astronomer at the U.S. National Radio Astronomy Observatory (NRAO). “This project shows how ALMA can resolve the internal structure of galaxies even in the distant Universe — revealing how they evolve, interact, and form stars.” By visualizing these clumps, the CRISTAL survey offers an in-depth look at the very nature of star formation in the early universe and its connection to the overall structure of galaxies.

Cold Gas and Cosmic Dust: Understanding the Role of Gas in Galaxy Formation

Another key aspect of the CRISTAL survey is its examination of the cold gas that permeates these early galaxies. This gas plays a vital role in the formation of new stars, serving as the raw material that fuels stellar birth. Observations showed that the cold gas often extended far beyond the visible stars, a clear indication that it was either feeding future star formation or being expelled through stellar winds. In some cases, this gas was found to form rotation patterns, which hint at the formation of early galactic disks—a precursor to the spiral galaxies that would later dominate the universe.

“These observations highlight ALMA’s potential as a time machine, allowing us to peer into the early ages of the Universe,” said Sergio Martín, Head of the Department of Science Operations at ALMA. “Programs like CRISTAL demonstrate the power of ALMA’s Large Programs to drive high-impact science. They allow us to tackle the big questions of cosmic evolution with the unprecedented depth and resolution that only a world-class observatory like ALMA can provide.” These findings not only reinforce the importance of gas in galactic formation but also demonstrate how ALMA’s advanced technology can help scientists peer deep into the universe’s history.

Scientists have observed a new type of black hole that is too heavy to have been born from a star but still too slim to act as an anchor for an entire galaxy. These black holes are being being referred to as “lite” intermediate-mass black holes (IMBH), and they’re extremely hard to identify because of how low-frequency their signals tend to be.

The quest to find these IMBHs has come about due to the fact that we’ve discovered ultramassive black holes that can measure up to millions of times the mass of our sun, while others can sit at just 50 solar masses or below. Astronomers wanted to understand where any mid-sized black holes might fit in, so they began looking harder.

What they discovered is that lite intermediate-mass black holes do indeed exist. However, finding them is difficult. To make it easier, the researchers used Virgo and LIGO, two gravitational wave detectors. Using the detectors, astronomers were able to find multiple black holes ranging in size from 100 to 300 times the mass of the sun.

While still massive, these black holes are not anywhere near powerful enough to have been born from dying stars or to hold galaxies together. So, where do they fit into the universe? Well, researchers believe they could have been born from mergers that happen out in the cosmos. While completing a run from 2019 to 2020, the LIGO and Virgo network logged 11 mergers that could fit the bill for these cosmic objects.

A study on the findings is published in The Astrophysical Journal Letters. In it, the researchers detail how they classified the new class of black holes, breaking down the exact way they discovered them and why they are so important. The hope is that some of these smaller black holes could offer us a glimpse into the time when the first stars lived and died.

As we detect more and more of these lite intermediate-mass black holes, researchers believe we find even more reason to be excited about them. Understanding them could not only unlock the secrets of the early universe, but it could also help us refine the models that we use to view the universe as a whole.

NASA’s New Horizons spacecraft has successfully demonstrated a revolutionary method for deep space navigation, as the probe ventured through the Kuiper Belt at a distance of more than 5.5 billion miles from Earth. This achievement, the first-ever successful deep space stellar navigation test, marks a significant leap forward in how we could navigate vast interstellar distances. The test, conducted by an international team of astronomers, involved the spacecraft capturing images of two of our closest stellar neighbors, Proxima Centauri and Wolf 359. This experiment, a proof-of-concept, not only showcased a new potential for navigation but also underlined the power of stellar parallax, a phenomenon where stars appear to shift position due to the observer’s movement. The results, accepted for publication in The Astronomical Journal, could lay the groundwork for future interstellar exploration, offering precise navigation systems for spacecraft venturing far beyond our solar system.

The Concept of Stellar Navigation and Parallax

Stellar navigation, an essential aspect of future deep space missions, relies on the ability to measure the position of stars relative to one another as seen from different vantage points in space. This principle is grounded in the concept of stellar parallax, the apparent shift in a star’s position due to the change in the observer’s location. The New Horizons test employed this technique, capturing images of two stars—Proxima Centauri at 4.2 light-years away and Wolf 359 at 7.86 light-years—using the spacecraft’s unique vantage point as it traversed the outer solar system. By measuring the apparent shift in these stars’ positions, astronomers were able to calculate the spacecraft’s location in space with remarkable accuracy. This test was groundbreaking in its scale and precision, demonstrating the feasibility of using stellar parallax for interstellar navigation.

The results from this test, while not yielding research-grade data, provided an insightful proof-of-concept for future space missions. In fact, the ability to pinpoint a spacecraft’s position with an accuracy of 4.1 million miles—roughly equivalent to 26 inches between New York and Los Angeles—demonstrates the potential of stellar navigation as a tool for long-duration space travel. As the New Horizons spacecraft continues its journey, these findings provide a critical reference point for future interstellar probes.

A New Era for Interstellar Navigation

This successful demonstration is not just a theoretical exercise, but a practical step toward establishing a new era of deep space exploration. “Taking simultaneous Earth/Spacecraft images we hoped would make the concept of stellar parallaxes instantly and vividly clear,” said Tod Lauer, an astronomer at NSF’s NOIRLab and lead author of the study. The ability to observe stellar positions from both Earth and spacecraft allowed the team to directly witness the phenomenon of parallax in action. Lauer emphasized the educational value of such an experiment, noting that it helped bring a theoretical concept to life in a very tangible way. The New Horizons team’s work is a testament to the growing sophistication of space missions, especially as humanity prepares for deeper explorations of the cosmos.

“It’s one thing to know something, but another to say ‘Hey, look! This really works!’” Lauer added. The successful implementation of stellar navigation in deep space serves as a clear affirmation that the technology could play a critical role in future interstellar missions. As more spacecraft venture beyond the outer limits of the solar system, the ability to rely on such navigation methods will become even more important.

Implications for Future Space Exploration

The implications of this experiment extend beyond just New Horizons. As NASA and other space agencies plan missions to explore distant regions of the galaxy, the ability to navigate effectively through interstellar space will become an essential component of these missions. New Horizons, already famous for its historic flyby of Pluto in 2015, has now made an equally important contribution to space science. By demonstrating the feasibility of deep space stellar navigation, the spacecraft has opened up new avenues for mission planning, potentially making long-distance missions to exoplanets or even interstellar space more realistic.

As the spacecraft continues its extended mission, studying the heliosphere and heading toward the boundary of interstellar space, the success of this navigation test underscores the potential of future missions to explore the cosmos in ways previously thought impossible. In the coming years, the New Horizons probe will cross the “termination shock,” the boundary marking the edge of the heliosphere and the beginning of true interstellar space. This crossing could provide the next major milestone in our understanding of the universe beyond the solar system.

The Path Ahead for Interstellar Exploration

While New Horizons was originally launched to study Pluto and its moons, its journey has now transformed into a pioneering mission for interstellar exploration. The test of stellar navigation in deep space could be a game-changer for humanity’s next steps into the cosmos. By refining methods of stellar navigation, space agencies can prepare for more ambitious missions, including potential visits to exoplanets in other star systems. As scientists continue to refine these techniques, the dream of exploring distant stars, and even interstellar space, is gradually becoming more attainable.

As New Horizons nears the boundary of interstellar space, its achievements in stellar navigation pave the way for more advanced and precise methods of navigating in the vast and unknown expanse beyond our solar system. The spacecraft’s work not only exemplifies NASA’s continued leadership in space exploration but also highlights the broader scientific community’s growing expertise in deep space navigation, promising a future where we can chart a course through the stars.

Dolphins and orcas, revered for their intelligence and agility, have reached a pivotal point in their evolutionary journey. New research has revealed that these marine mammals, once land-dwellers, have evolved to a stage where returning to life on land is biologically impossible. A breakthrough study underscores that after millions of years of evolutionary change, dolphins and orcas are now forever bound to the ocean.

A Critical Evolutionary Milestone

Published in Proceedings of the Royal Society B, the study scrutinized over 5,600 mammal species to understand how dolphins and orcas evolved from semi-aquatic ancestors to fully marine life forms. The research, led by Bruna Farina, a PhD candidate at the University of Fribourg in Switzerland, concludes that the transition from semi-aquatic to fully aquatic is a one-way path. Once a species makes this leap, its evolutionary direction becomes irreversible.

Farina’s team found that this transition occurred millions of years ago when mammals returned to the sea. Unlike their terrestrial predecessors, dolphins and orcas cannot evolve back to a land-based lifestyle. Their adaptations—such as specialized limbs, unique diets, and reproductive systems—have become so ingrained that reversing these traits is no longer possible.

The Cost of Specialization

Dolphins and orcas are the epitome of specialized marine predators. Over time, they have adapted to life in the ocean in remarkable ways. Their larger body sizes help conserve heat in cold waters, while their diets evolved to sustain the high metabolic demands of life underwater. Their limbs evolved into flippers, and their tails became powerful tools for propulsion, allowing them to navigate the seas with unmatched precision. Even their reproductive systems have adjusted to facilitate aquatic births.

While these adaptations are crucial for survival in the ocean, they come at a cost. The traits that make these creatures so successful in their marine environment have also made it impossible for them to revert to life on land. According to Dollo’s Law, once a complex trait is lost through evolution, it is highly unlikely to reappear. This principle underscores the irreversible nature of the changes dolphins and orcas have undergone.

The Risk of Extreme Specialization

Although dolphins and orcas are highly efficient predators in the ocean, their extreme specialization also makes them vulnerable. The more specialized a species becomes, the less adaptable it is to environmental changes. For these marine mammals, this means their survival is tightly linked to the health of marine ecosystems.

As climate change, ocean acidification, and pollution continue to threaten marine habitats, the specialized traits of dolphins and orcas could become a liability. If ocean conditions worsen beyond their capacity to cope, these species will have no evolutionary backup plan to adapt. This lack of flexibility poses a serious threat to their long-term survival.