Category: 7. Science

Mitochondria are the body’s “energy factories,” and their proper function is essential for life. Inside mitochondria, a set of complexes called the oxidative phosphorylation (OxPhos) system acts like a biochemical assembly line, transforming oxygen and nutrients into usable energy.

Now, the study, led by the GENOXPHOS group at the Spanish National Centre for Cardiovascular Research (CNIC) and the Biomedical Research Networking Centre in the area of Frailty and Healthy Ageing (CIBERFES), and directed by Dr. José Antonio Enríquez, has revealed how this system evolved over millions of years-from the first vertebrates to modern humans. “Understanding this evolution helps explain why some genetic mutations cause rare but serious diseases that affect the OxPhos system,” say José Luis Cabrera the leading author of the study.

Published in Cell Genomics, the study describes the molecular evolutionary strategies of the OxPhos system, the main site of metabolic and energy integration in the cell. It also shows how this information can be used to identify mutations that cause disease.

Working in collaboration with Fátima Sánchez-Cabo, head of the CNIC Computational Systems Biomedicine group, the researchers analyzed the interaction between the two types of DNA that encode OxPhos proteins: nuclear DNA (inherited from both parents) and mitochondrial DNA (inherited only from the mother).

The OxPhos system, explains José Antonio Enríquez-head of the CNIC Functional Genetics of the Oxidative Phosphorylation System (GENOXPHOS) group-comprises five large protein complexes: four that transport electrons and one, called ATP synthase, that produces ATP, the cell’s molecular “fuel.”

These complexes can work individually or in combination, depending on the cell’s energy needs. Together, they are made up of 103 proteins encoded by two different genomes: nuclear and mitochondrial. While nuclear DNA changes slowly over time and gains variation through genetic mixing during reproduction, mitochondrial DNA evolves much more rapidly but is passed only through the maternal line.”

Dr. José Antonio Enríquez, GENOXPHOS Lab, CNIC

Dr. Cabrera adds that the proteins encoded by mitochondrial DNA form the core of the respiratory complexes, “so proper function depends on precise compatibility between the nuclear and mitochondrial components.”

The study also introduces an innovative new tool: ConScore, a predictive index that assesses the clinical relevance of mutations in the 103 OxPhos proteins. “ConScore is based on the evolutionary divergence of these proteins across vertebrates-including primates and other mammals-and complements human population genetic data,” says Enríquez.

The authors affirm that ConScore provides a new framework for interpreting potentially pathogenic mutations, opening the door to improved diagnosis and treatment of mitochondrial diseases.

Ultimately, the researchers conclude, this study not only advances our understanding of how human cells evolved, but also brings us closer to new solutions for patients with rare genetic diseases.

Introduction – The Unfinished Story of RNA

In a recent lecture on RNA Biology by Dr. Fazal Adnan, the Head of the Department at Atta Ur Rahman School of Applied Biosciences in Islamabad, presented an intriguing illustration (see Figure 1), that truly ignited curiosity among all of us students. This captivating image not only piqued scientific curiosity but also inspired a deeper conversation about human molecular biology and its evolution. It made me reflect on both the incredible advancements we have made in the past and appreciate the journey of discovery that has brought us to where we are today. 

It is a widely accepted practice to express gratitude to our ancestors for their contributions in advancing civilization and transforming our way of life. But what if I tell you that our bodies have a similar practice. Just like we honor those who came before us, our cells remember past infections through integrating invader sequences in our genome, helping our cells recognize and combat similar threats in the future. Isn’t that incredible? It’s a fascinating dance of human evolution alongside the evolution of microbes. So, who’s the smarter one in this partnership? Well, this is about the untold story of RNA biology that has revolutionized our understanding of molecular defense. Let’s dive into it. 

A recent article published in Nature raised a critical question: Why is RNA structure so difficult to predict? While many bioinformatics platforms have successfully tackled protein analysis, they fall short in RNA prediction. This discrepancy highlights a significant challenge in our field, and we must delve into this question, as understanding RNA structure is key to advancing our knowledge in molecular biology and therapeutics.

For many years, RNA has served as an intermediary component within the framework of the central dogma of molecular biology. Then the discovery of ribozymes, the identification of RNA as a catalyst, and the understanding of the RNA world hypothesis have significantly heightened scholarly interest in the study of RNA. 

The true importance of RNA began to shine through in 1974, when groundbreaking research unveiled its remarkable ability to self-modify. This unique trait allows RNA to carry out crucial functions that help safeguard the integrity of the cell and its entire cellular system. This process of regulation through inducing chemically modified tags annotates the sequence to functionalize and generate a desired product. The Accumulation of sequences from past generations has aided in the evolution of the genome to increase its fitness. This fascinating interplay reveals just how adaptable and vital RNA is to life itself.

This has led to the emergence of Epitrancriptomics, which encompasses post-transcriptional modifications that do not affect the base sequence. These modifications have significant implications for the final structure, stability, and translation efficiency of RNA molecules. These chemical modifications control gene expression beyond the DNA sequence. 

Cracking The RNA Code: What Is Epitranscriptomics?

The genetic code can be likened to a language that narrates the experiences and resilience of human beings throughout their lives (see Figure 2). This code, composed of the four nucleotides adenine (A), uracil (U), guanine (G), and cytosine (C), conveys essential biological information. Furthermore, RNA modifications function as grammatical rules that enhance and clarify the meanings conveyed by the genetic sequence. To date, over 170 distinct types of RNA modifications have been identified across various forms of RNA, underscoring the intricate nature of genetic regulation. These modifications are not just static; they’re dynamic and reversible, tightly orchestrated by specialized enzymes. You can think of them as the storytellers in this biological tale: where “writers“(METTL3, METTL14) introduce transformative edits, “erasers“ (FTO, ALKBH5) refine them, and “readers” (YTHDF1, YTHDF2, IGF2BP1) interpret their significance. Embracing this complexity opens up a deeper understanding of the full spectrum of genetic expression.

Epitranscriptomics is an intriguing RNA editing mechanism that sets itself apart from epigenetics. While epigenetics focuses on how chemical modifications influence gene expression, epitranscriptomics delves into the realm of RNA itself. It’s a fascinating layer of gene regulation that actively transforms the RNA message, shaping its destiny in unique ways. Imagine the power of writing directly on RNA, altering its fate and function; this is the dynamic world of epitranscriptomics!

Many different chemical changes can happen to RNA, but N6-methyladenosine stands out as a very important molecular switch. This modification plays a critical role, allowing the cell to adapt to its dynamic needs. 

On the other hand, alterations like acetylation and pseudouridylation improve RNA’s regulatory capabilities even more. They increase the stability of the molecule, enhance its ability to fold, and maintain the integrity of its intricate two- and three-dimensional structures. Because of its crucial function in post-transcriptional control, this vast panorama of alterations highlights the immense complexity and distinctiveness of RNA. A relevant question is raised: might these RNA alterations play a significant role in clarifying the mechanisms behind aging, disease, and evolutionary processes? A pertinent inquiry arises: could these RNA modifications serve as key factors in elucidating the mechanisms underlying disease, aging, and evolutionary processes?

The Groundbreaking Discoveries That Changed RNA Biology

The epitranscriptomics and its application in research and development have opened new avenues and have answered some of the important questions on evolution and the role of molecular agents in it. The most significant application is the development of technology to map all the chemical modifications on the transcriptome, which can tell a lot about human health and disease and the adaptive trails a cell undergoes. For example, if we want to study cancer, we can check for RNA alterations, to seek specific modifications specific to that pathogenesis could help to develop novel targets for drug development and understanding how a cell undergoes dysfunction. 

One of the most significant and potent examples is the development of the COVID-19 vaccine, where chemical alterations have been made to mRNA coding for the protein of interest, increasing the vaccine efficacy while minimizing the unwanted immune reactions. This is the way that understanding chemical modifications for safety profiles of many potent vaccines and therapeutic drugs accelerates the research advancement and provides a novel platform to tackle critical health concerns.

The Living and the Dead Li’s Elements

Historically, the epitranscriptomic encompasses the chemical changes such as methylation, acetylation, and pseudouridinylation, but now it has added some new modes of changes. Xiong et al reported that this region also includes RNA control by retrotransposition, which is assisted by the m6A alteration. These retrotransposons provide prospective targets for RNA modification. 

A study by Dominissini et al distinguishes between “living” (retrotranspositionally competent) and “dead” (retrotranspositionally incompetent) L1 components where data indicates that m6A enhances the activity of functional “living” L1 sequences while simultaneously serving a significant role for “dead” L1 sequences. These “dead” L1 sequences can influence the host organism by inhibiting genes that typically suppress the transposition of “living” L1s. Moreover, these alterations exhibit non-random characteristics and are preserved, signifying that their involvement in retrotransposition represents a strategic framework designed to promote genomic stability and foster functional diversity. 

VIP pass to tiny RNA molecules

Small RNAs, known for their existence in plants and traditional therapeutic practices, face considerable obstacles when they travel through the human digestive system. These small compounds are naturally delicate and have difficulty passing through the membranes, which causes their degradation through the body’s surveillance system, before they can induce their potential effects. Despite facing numerous challenges, the remarkable potential of these biomolecules to transform various aspects is truly promising and should not be overlooked.

Guo et al performed research on Ban Zhi Liana, a herb in traditional Chinese medicine where the isolated crude extract contains the specifically modified small RNAs. These are natural, particularly the two fascinating types: 2′-O-methylation (2′-O-Me) and N6-methyladenosine (m6A). Furthermore, the investigation has also found an additional modification known as 5-methylcytidine (m5C); however, this particular modification did not demonstrate the same exceptional advantages as the others. These findings offer a promising perspective on the potential of natural compounds to advance health and therapeutic applications.

The Next Frontier: Can We Hack RNA Modifications for Medicine?

In the above mentioned context, the field of epitranscriptomics is rapidly evolving, providing great opportunities for revealing previously unknown facts within scientific inquiry. Looking ahead, we may anticipate the development of novel instruments and assays, which will pave the way for further in-depth study in RNA biology, covering topics such as aging and cancer, allowing the detection of changes at the individual cell level. Such breakthroughs will allow us to monitor organ health with great accuracy. The advancement of knowledge and technologies to map all chemical changes in a transcriptome will enable the screening of lethal and healthy tags, and techniques to restore them. Here, CRISPR-based tools are transforming the utilization of chemical tags from diagnostics to therapeutics, allowing researchers to add or remove critical modifications with precision. This advancement is laying the groundwork for next-generation theragnostics, in which physicians may one day be able to address diseases by directly targeting RNA and making diagnostics more sensitive and precise.

We are just beginning to unlock the mysteries of RNA and its critical role in understanding how our bodies function. In the not-so-distant future, we will gain insights into how our bodies heal, all thanks to the fascinating world of RNA biology. It’s an exciting time to be part of this journey.

References

Bhat, S. S., Bielewicz, D., Jarmolowski, A., & Szweykowska-Kulinska, Z. (2018). N6-methyladenosine (m6A): Revisiting the Old with Focus on New, an Arabidopsis thaliana Centered Review. Genes, 9(12), 596. https://doi.org/10.3390/genes9120596

Cerneckis, J., Ming, G.-L., Song, H., He, C., & Shi, Y. (2024). The rise of epitranscriptomics: Recent developments and future directions. Trends in Pharmacological Sciences, 45(1), 24–38. https://www.cell.com/trends/pharmacological-sciences/fulltext/S0165-6147(23)00254-7

Dominissini, D., Moshitch-Moshkovitz, S., Schwartz, S., Salmon-Divon, M., Ungar, L., Osenberg, S., Cesarkas, K., Jacob-Hirsch, J., Amariglio, N., & Kupiec, M. (2012). Topology of the human and mouse m6A RNA methylomes revealed by m6A-seq. Nature, 485(7397), 201–206. https://idp.nature.com/authorize/casa?redirect_uri=https://www.nature.com/articles/nature11112&casa_token=998Qh-5Va2cAAAAA:InO38ZnffREIuw_ScTtRKxGpwzFdbabgd0mQRmMDeDoJIkshEt5L39MG4Lc2K_sXGYe8FtxUM293sYqm0g

Guo, S., Li, Z., Li, X., Liang, Z., Zhao, D., Sun, N., Liu, J., Wang, X., Mei, S., & Qiao, X. (2025). 2′-O-methylation and N6-methyladenosine enhance the oral delivery of small RNAs in mice. Molecular Therapy Nucleic Acids. https://www.cell.com/molecular-therapy-family/nucleic-acids/fulltext/S2162-2531(25)00128-3

Kwon, D. (2025). RNA function follows form-why is it so hard to predict? Nature, 639(8056), 1106–1108. https://pubmed.ncbi.nlm.nih.gov/40128371/

Xiong, F., Wang, R., Lee, J.-H., Li, S., Chen, S.-F., Liao, Z., Hasani, L. A., Nguyen, P. T., Zhu, X., & Krakowiak, J. (2021). RNA m6A modification orchestrates a LINE-1–host interaction that facilitates retrotransposition and contributes to long gene vulnerability. Cell Research, 31(8), 861–885. https://www.nature.com/articles/s41422-021-00515-8

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In 2019, researchers with the XENON Collaboration saw something unexpected. The device is designed to find evidence of the elusive dark matter, a hypothetical substance that is believed (with good reason) to exist everywhere. Instead, it saw something weird happening to the xenon in the device. One of the atoms decayed. This was a surprise as the half-life for that particular xenon was a half-life of 18 billion trillion years. That’s more than 1 trillion times longer than the current age of the universe.

This has been described as the rarest event ever recorded, and it is not hyperbole. Still, it is important to understand the meaning and context of a half-life of 18 billion trillion years, and how in the end we can see such an event, even if they are extremely rare. The term “half-life” refers to the amount of time it takes for half of a given quantity of a specific atom to decay into another form.

When we think of radioactive decay, we tend to think of things happening very fast. There’s a good reason for that. With the advent of the nuclear age, discussions of half-life have all been about unstable elements that disappear in seconds and can trigger explosive chain reactions. In medicine, we use radioactive elements that might decay in hours or days, but their half-lives might be a lot longer than that.

Take Uranium, for example. Its most common form has a half-life of almost 4.5 billion years. So when the Earth formed, it had twice as much Uranium. Still, you wouldn’t want to be near Uranium for long, because the atoms do decay constantly, albeit slowly. Uranium is not super dangerous naturally, but it is in our uses that can pose a more serious health risk.

Still, the half-life of xenon-124 is about 4 trillion times longer than that of uranium-238. How did we even measure that? The detector has 2 metric tons of xenon in it, which is almost 10,000 trillion trillion atoms. So if you put enough of these atoms together, you should see a single atom decaying every few minutes.

Should is the operative word here. Because looking at atoms is not like looking at a handful of red marbles waiting for one to turn blue. It is like looking at an overwhelming number of marbles, where one might get slightly more massive and create a flash of x-rays or throw away an electron. In 177 days of data collection, the team saw around 9 events.

A problem with a lot of these rare events with an enormous half-life is actually catching them in the act. And without seeing the event, we do not even know if it happens. 

Take the proton, for example, the tiny, positively charged particle at the heart of every atom. Some theories in physics predict that protons might eventually decay. But so far, in all of our experiments, we’ve never seen it happen. That means if proton decay does occur, it must take an incredibly long time, so long, in fact, that scientists estimate its half-life to be at least 1.67 billion trillion trillion years. 100 billion times longer than Xenon-124.

It is not easy looking for events that make the lifetime of stars look like seconds.  

The observations were reported in detail in the journal Nature.

An earlier version of this story was published in 2019.

A new study reveals that humans were extensively using fire to modify landscapes as far back as 50,000 years ago. That’s at least 10,000 years earlier than previously believed. Scientists uncovered this clue in a 300,000-year-old sediment core extracted from the East China Sea.

The core contained fossilized charcoal, microscopic remnants of plant matter burned but not fully consumed. Known as pyrogenic carbon, these particles drifted into the sea via rivers over tens of thousands of years. They serve as an enduring record of fire on land.

A Fire Signature That Outpaced Climate

The research team, led by Dr. Debo Zhao from the Institute of Oceanology at the Chinese Academy of Sciences, found something unexpected. Around 50,000 years ago, levels of pyrogenic carbon suddenly spiked. The timing didn’t line up with known climate patterns. It suggested something new was at play.

“Our findings challenge the widely held belief that humans only began influencing geological processes in the recent past—during the last Ice Age and the ensuing Holocene,” said Dr. Zhao.

Instead, the evidence points to humans (modern Homo sapiens) as the likely culprits. This timeline aligns with archaeological records showing a rapid expansion of Homo sapiens across Eurasia, Southeast Asia, and into Australia between 70,000 and 50,000 years ago.

In each of these regions, fire activity began to rise dramatically. But this wasn’t wildfire season. These were intentional flames.

A Record of Ice and Fire

As the climate cooled during glacial periods, fire became indispensable. It helped early humans cook food, stay warm, fend off predators, and migrate into colder, more challenging landscapes. But it also transformed those landscapes.

“Humans likely began shaping ecosystems and the global carbon cycle through their use of fire even before the Last Ice Age,” said Dr. Stefanie Kaboth-Bahr, a paleontologist at Freie Universität Berlin and coauthor of the study.

The fire’s effects were lasting. Burning vegetation releases carbon into the atmosphere. Doing this repeatedly over large areas eventually warms the planet, albeit by a very tiny amount compared to present-day industrial activity.

The discovery suggests that humans began influencing the Earth’s carbon cycle tens of thousands of years earlier than scientists had assumed. “Even during the Last Glaciation, the use of fire had probably started to reshape ecosystems and carbon fluxes,” added Professor Wan Shiming, another corresponding author.

The Global Signature of Humanity’s First Flames

The researchers compared the East Asia findings with data from Europe, Southeast Asia, and Papua New Guinea–Australia. The same pattern emerged in each region: a sudden uptick in fire activity starting roughly 50,000 years ago.

Crucially, this fire surge appeared even where natural conditions—like rainfall or lightning—wouldn’t account for such increases. Something else had to be driving it. The clearest candidate: humans.

The study also suggests that this early fire use was systematic enough to leave a lasting mark on Earth’s geological record—what some scientists refer to as the pyroscape, the legacy of fire through time.

This study underscores how early and profoundly humans began altering the planet. It challenges the idea that the Anthropocene (our proposed new geological epoch) begins with agriculture or the Industrial Revolution. Instead, the spark might have been struck much earlier, with the simple but powerful act of lighting a fire.

Kaboth-Bahr’s research is part of a larger initiative called The Burning Question, which investigates the role of fire in shaping ecosystems across Eastern Africa. Supported by the German Research Foundation and partners in Ethiopia, the project seeks to understand fire’s ecological, climatic, and cultural significance over the last 600,000 years.

The findings appeared in the Proceedings of the National Academy of Sciences.

An international research team led by scientists from the University of Vienna has uncovered new insights into how specialized cell types and communication networks at the interface between mother and fetus evolved over millions of years. These discoveries shed light on one of nature’s most remarkable innovations – the ability to sustain a successful pregnancy. The findings have just been published in Nature Ecology & Evolution.

Pregnancy that lasts long enough to support full fetal development is a hallmark evolutionary breakthrough of placental mammals – a group that includes humans. At the center of this is the fetal-maternal interface: the site in the womb where a baby’s placenta meets the mother’s uterus, and where two genetically distinct organisms – mother and fetus – are in intimate contact and constant interaction. This interface has to strike a delicate balance: intimate enough to exchange nutrients and signals, but protected enough to prevent the maternal immune system from rejecting the genetically “foreign” fetus.

To uncover the origins and mechanisms behind this intricate structure, the team analyzed single-cell transcriptomes – snapshots of active genes in individual cells – from six mammalian species representing key branches of the mammalian evolutionary tree. These included mice and guinea pigs (rodents), macaques and humans (primates), and two more unusual mammals: the tenrec (an early placental mammal) and the opossum (a marsupial that split off from placental mammals before they evolved complex placentas).

A cellular “atlas of mammal pregnancy”

By analyzing cells at the fetal-maternal interface, the researchers were able to trace the evolutionary origin and diversification of the key cell types involved. Their focus was on two main players: placenta cells, which originate from the fetus and invade maternal tissue, and uterine stromal cells, which are of maternal origin and respond to this invasion.

Using molecular biology tools, the team identified distinct genetic signatures – patterns of gene activity unique to specific cell types and their specialized functions. Notably, they discovered a genetic signature associated with the invasive behavior of fetal placenta cells that has been conserved in mammals for over 100 million years. This finding challenges the traditional view that invasive placenta cells are unique to humans, and reveals instead that they are a deeply conserved feature of mammalian evolution. During this time, the maternal cells weren’t static, either. Placental mammals, but not marsupials, were found to have acquired new forms of hormone production, a pivotal step toward prolonged pregnancies and complex gestation, and a sign that the fetus and the mother could be driving each other’s evolution.

Cellular dialogue: Between cooperation and conflict

To better understand how the fetal-maternal interface functions, the study tested two influential theories about the evolution of cellular communication between mother and fetus.

The first, the “Disambiguation Hypothesis,” predicts that over evolutionary time, hormonal signals became clearly assigned to either the fetus or the mother – a possible safeguard to ensure clarity and prevent manipulation. The results confirmed this idea: certain signals, including WNT proteins, immune modulators, and steroid hormones, could be clearly traced back to one source tissue.

The second, the “Escalation Hypothesis” (or “genomic Conflict”), suggests an evolutionary arms race between maternal and fetal genes – with, for example, the fetus boosting growth signals while the maternal side tries to dampen them. This pattern was observed in a small number of genes, notably IGF2, which regulates growth. On the whole, evidence pointed to fine-tuned cooperative signaling.

These findings suggest that evolution may have favored more coordination between mother and fetus than previously assumed. The so-called mother-fetus power struggle appears to be limited to specific genetic regions. Rather than asking whether pregnancy as a whole is conflict or cooperation, a more useful question may be: where is the conflict?”

Daniel J. Stadtmauer, lead author of the study and researcher at the Department of Evolutionary Biology, University of Vienna

Single-cell analysis: A key to evolutionary discovery

The team’s discoveries were made possible by combining two powerful tools: single-cell transcriptomics – which captures the activity of genes in individual cells – and evolutionary modeling techniques that help scientists reconstruct how traits might have looked in long-extinct ancestors. By applying these methods to cell types and their gene activity, the researchers could simulate how cells communicate in different species, and even glimpse how this dialogue has evolved over millions of years.

“Our approach opens a new window into the evolution of complex biological systems – from individual cells to entire tissues,” says Silvia Basanta, co–first author and researcher at the University of Vienna. The study not only sheds light on how pregnancy evolved, but also offers a new framework for tracking evolutionary innovations at the cellular level – insights that could one day improve how we understand, diagnose, or treat pregnancy-related complications.

The research was conducted in the labs of Mihaela Pavličev at the Department of Evolutionary Biology, University of Vienna, and Günter Wagner at Yale University. Wagner is Professor Emeritus at Yale and a Senior Research Fellow at the University of Vienna. The study was supported by the John Templeton Foundation and the Austrian Science Fund (FWF).

There is no better excuse to travel than to see a total solar eclipse, and the next one happens on Aug. 12, 2026. Although a total solar eclipse is an unforgettable experience, totality lasts only a few minutes. So what do you do before and after the eclipse?

Boredom won’t be a problem for the 2026 total solar eclipse, with some truly spectacular locations and popular vacation areas in or close to the path of totality. From Greenland to Spain, there are myriad unique experiences and off-the-beaten-track itineraries that offer much more than nature’s greatest spectacle.

The cycle of metals between the gas and the dust phases in the neutral interstellar medium (ISM) is an integral part of the baryon cycle in galaxies.

The resulting variations in the abundance and properties of interstellar dust have important implications for how accurately we can trace the chemical enrichment of the universe over cosmic time.

Multi-object UV spectroscopy with HWO can provide the large samples of abundance and dust depletion measurements needed to understand how the abundance and properties of interstellar dust vary within and between galaxies, thereby observationally addressing important questions about chemical enrichment and galaxy evolution.

Medium-resolution (R~50,000) spectroscopy in the full UV range (950-3150 A) toward massive stars in Local Volume galaxies (D < 10 Mpc) will enable gas- and dust-phase abundance measurements of key elements, such as Fe, Si, Mg, S, Zn. These measurements will provide an estimate of how the dust abundance varies with environment, in particular metallicity and gas density.

However, measuring the carbon and oxygen contents of dust requires very high resolution (R > 100,000) and high signal-to-noise (S/N > 100) owing to the non-saturated UV transitions for those elements being extremely weak. Since carbon and oxygen in the neutral ISM contribute the largest metal mass reservoir for dust, it is critical that the HWO design include a grating similar to the HST STIS H gratings providing very high resolution, as well as FUV and NUV detectors capable of reaching very high S/N.

Julia Roman-Duval, Yumi Choi, Mederic Boquien

Comments: 12 pages; 6 figures; will be published in ASP conference proceedings of the HWO2025 conference
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2507.00201 [astro-ph.GA] (or arXiv:2507.00201v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2507.00201
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Submission history
From: Julia Roman-Duval
[v1] Mon, 30 Jun 2025 19:10:27 UTC (663 KB)
https://arxiv.org/abs/2507.00201
Astrobiology

Understanding where and in what quantities essential elements for life have existed on Earth’s surface helps explain the origin and evolution of life. Phosphorus (P) is one such element, forming the backbone of DNA, RNA, and cellular membranes. On Earth’s surface, P is primarily preserved in rocks in the form of phosphate minerals. However, these phosphate minerals are generally insoluble. Therefore, scientists have long struggled to answer the question of under what conditions P could have become concentrated on the early Earth.

Now, a research team comprising Yuya Tsukamoto and Takeshi Kakegawa from Tohoku University may have found the answer. For the first time, they have uncovered geochemical and mineralogical evidence that submarine hydrothermal alteration may have been a significant source of P on the early Earth.

“We analyzed 3.455-billion-year-old basaltic seafloor rocks in drill core samples recovered from the Pilbara Craton, Western Australia, discovering that P was significantly leached from the hydrothermally altered rocks compared to the least altered rocks” with further mineralogical analyses indicating that phosphate minerals had undergone dissolution in rocks where P was depleted explains,” explains Tsukamoto. “In other words, these hydrothermal processes may have released phosphorus from the rocks into the surrounding seawater, enriching early oceans with this essential nutrient.”

Schematic image of this study. ©Tsukamoto and Kakegawa et al. — Tohoku University

The team identified that this significant dissolution was caused by two types of hydrothermal fluids: sulfidic and high-temperature fluids, and mildly acidic to alkaline and relatively low-temperature fluids. In particular, the latter fluids are characteristic of the Archean, reflecting a high CO₂ atmosphere at that time.

Calculations indicated that these latter fluids could contain up to 2 mM phosphate, approximately 1,000 times higher than modern seawater concentrations. Furthermore, calculations based on the study’s analytical results suggested that the annual flux of P from Archean submarine hydrothermal fluids could have been comparable to that supplied to the modern ocean by continental weathering.

“Importantly, this study provides direct evidence that submarine hydrothermal activity leached P from seafloor basaltic rocks and quantifies the potential P flux from these hydrothermal systems to the early ocean,” adds Tsukamoto. “Our findings demonstrate that hydrothermal systems could have locally supplied sufficient P to support early microbial ecosystems. These environments may have served as cradles for early life and played a significant role in the origin and evolution of life.”

The study also highlights the potential impact of hydrothermal fields not only on the seafloor but also in terrestrial settings such as hot springs. Future research on phosphate behavior in hydrothermally altered rocks through time will further reveal shifts in P cycles on the early Earth.

Details of the study were published in the journal Geochimica et Cosmochimica Acta on June 18, 2025.

Phosphate behavior during submarine hydrothermal alteration of ca. 3.455 Ga basaltic seafloor rocks from Pilbara, Western Australia, Geochimica et Cosmochimica Acta

Astrobiology

Cosmochemical studies have proposed that Earth accreted roughly 5-10% of its mass from carbonaceous (CC) material, with a large fraction delivered late via its final impactor, Theia (the Moon-forming impactor). ‘

Here, we evaluate this idea using dynamical simulations of terrestrial planet formation, starting from a standard setup with a population of planetary embryos and planetesimals laid out in a ring centered between Venus and Earth’s orbits, and also including a population of CC planetesimals and planetary embryos scattered inward by Jupiter.

We find that this scenario can match a large number of constraints, including i) the terrestrial planets’ masses and orbits; ii) the CC mass fraction of Earth; iii) the much lower CC mass fraction of Mars, as long as Mars only accreted CC planetesimals (but no CC embryos); iv) the timing of the last giant (Moon-forming) impact; and v) a late accretion phase dominated by non-carbonaceous (NC) bodies.

For this scenario to work, the total mass in scattered CC objects must have been ~ 0.2 – 0.3 M⊕ , with an embryo-to-planetesimal mass ratio of at least 8, and CC embryos in the ~ 0.01 – 0.05 M⊕ mass range.

In that case, our simulations show there are roughly 50-50 odds of Earth’s last giant impactor (Theia) having been a carbonaceous object – either a pure CC embryo or an NC embryo that previously accreted a CC embryo. Our simulations thus provide dynamical validation of cosmochemical studies.

Duarte Branco, Sean N. Raymond, Pedro Machado

Comments: 20 pages, 11 figures, to be published in Icarus
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2507.01826 [astro-ph.EP] (or arXiv:2507.01826v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2507.01826
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Submission history
From: Duarte Branco
[v1] Wed, 2 Jul 2025 15:41:34 UTC (2,574 KB)
https://arxiv.org/abs/2507.01826

Astrobiology,