Ocean acidification results from oceanic uptake of anthropogenic CO2 (ΔCant). Weak carbonate buffering capacity (high Revelle factor, RF) amplifies acidification, but its role in persistently low-oxygen, poorly ventilated regions is unclear. Here we compare preindustrial to present changes in partial pressure of CO2 (pCO2), hydrogen ion concentration ([H+]), pH, aragonite saturation state (Ωara), and RF within permanent oxygen minimum zones (OMZs) versus well-ventilated regions. We find that acidification is negligible in the least-ventilated, poorly buffered lower OMZs, but detectable in moderately ventilated upper OMZs. In upper OMZs, pCO2 and [H+] increase faster while Ωara, pH, and RF change more slowly than in adjacent well-ventilated regions. Our analysis reveals that limited ΔCant delivery by ventilation ultimately constrain acidification in low-oxygen regions. Accordingly, low-oxygen regions with poor ventilation will experience less acidification than well-ventilated regions, and different metrics (notably [H+] versus Ωara) respond distinctly due to their different definitions and sensitivities.
Continue reading ‘Ventilation and buffering capacity effects on ocean acidification in low oxygen environments’Ventilation and buffering capacity effects on ocean acidification in low oxygen environments
Published 30 December 2025 Science ClosedTags: chemistry, methods
Century-old corals reveal the Pacific Northwest is acidifying faster than expected
Published 23 December 2025 Web sites and blogs Closed
Vermillion rockfish and soft coral observed during an expedition in Channel Islands National Marine Sanctuary. Image courtesy of Marine Applied Research and Exploration, NOAA.
- When compared with historical samples, corals show that the Salish Sea and California Current System are acidifying faster than anticipated because of greenhouse gas emissions. Models indicate that at this rate, carbon dioxide levels in the oceans will continue rising faster than concentrations in the atmosphere.
- Increasingly acidic seas pose growing risks to sensitive marine life, from clams and oysters to any organism with a spine, as well as economically important fisheries and the communities that depend on them.
- British marine ecologist Stephen Widdicombe calls the threat existential. Our continued failure to cut emissions can only lead to “a world where uncontrolled climate change including ocean acidification leaves us with an ocean that is less productive, less diverse and less able to provide humans with the wealth of services that we currently all benefit from,” he said.
In 1888, researchers aboard the R/V Albatross began the world’s first concentrated marine research expeditions off California’s Pacific coast. The team collected untold plant and animal specimens, including orange cup corals, which they carefully preserved and stored in collections at the Smithsonian Institution.
These specimens have now become rare physical evidence of ongoing changes in the chemistry of the Pacific Ocean as seawater absorbs the carbon dioxide released into the atmosphere by burning fossil fuels.
Researchers recently analyzed these 130-year-old samples, which come from a time before the Industrial Revolution’s greenhouse gas impacts had really kicked in. Then they compared them with new specimens collected in the same locations by a team aboard another research vessel, the R/V Rachel Carson, in 2020.
They discovered that this region is acidifying, far faster than models have predicted, findings they recently published in the journal Nature Communications.
“Ocean acidification is not a distant or abstract phenomenon. It is already underway, it is amplified in some regions, and it has real consequences for ecosystems and coastal economies today,” study lead author Mary Margaret Stoll, from the University of Washington, told Mongabay.
This research focused on the Salish Sea and the cold California Current System, an interweave of four currents predominantly flowing south from the Canadian province of British Columbia to the Mexican state of Baja California. Prevailing winds push water away from the coast along these currents, drawing water up from the deep, bringing nutrient-rich sediments along with it. These support exceptional biodiversity and lucrative fisheries.
Continue reading ‘Century-old corals reveal the Pacific Northwest is acidifying faster than expected’Dive deep into the critical environmental issue of ocean acidification and discover its devastating impact on krill, a tiny creature with a colossal role in marine ecosystems.
This video uncovers the intricate science behind how changing ocean chemistry threatens krill populations worldwide. In this video, you will learn:
- How rising CO2 levels lead to ocean acidification.
- The specific biological mechanisms by which acidification harms krill’s shells and physiology.
- The cascading effects of krill decline on the entire Antarctic food web.
- The broader implications of ocean acidification for marine biodiversity and global climate.
Ocean in coastal areas becoming more acidic than previously thought
Published 18 November 2025 Press releases ClosedNew research from the university of St Andrews has found that some coastal areas will become much more acidic than previously anticipated.
Because atmospheric CO2 and ocean pH (acidity) are tightly coupled, the more CO2 that is released into the atmosphere, the more is absorbed by seawater, making the ocean progressively more acidic. However, in a paper published in Nature Communications, researchers, using the California Current as an example, show that oceanic upwelling systems actually amplify ocean acidification.
Upwelling is where nutrient- rich and already acidic waters from deep in the oceans rise along the coast. When organic matter from the surface ocean sinks to the deep ocean, microbes gradually break it down in a chemical reaction that releases CO2 and increases seawater acidity. When this deep water upwells, it brings the acidity to the surface, where it further reacts with the atmospheric CO2, which makes these water masses even more acidic.
The researchers used historic coral samples and boron isotope signatures recorded in their skeletons to reconstruct how acidity changed over the 20th century, and then applied a regional ocean model to predict how acidity will change during the 21st century. The study showed that in these upwelling regions of the ocean, ocean acidification outpaces the level “expected” from rising atmospheric CO2 alone. This is because the upwelled water masses are acidic to start with and anthropogenically rising CO2 exacerbates the acidity.
Upwelling systems are among the most productive systems on our planet and support much of the world’s fisheries. Understanding how they respond to rising CO2₂ is therefore not only critical for ocean science, but also carries major implications for fisheries and their potential vulnerabilities.
Co Author Dr Hana Jurikova, Senior Research Fellow in from the School of Earth and Environmental Science, said: “Predicting how upwelling systems will respond to climate change is highly complex, as anthropogenic influences interact with natural sources of ocean acidification. Our research shows that such interactions can amplify environmental change in the California Current System, highlighting the need for similar studies in other regions to better anticipate future change.”
The California Current can be used as an example of other upwelling systems. Other important areas of coastal upwelling around the world include the Humbold Current off the coast of Peru or the Benguela and Canary Currents off the coast of west Africa.
Co Author Dr James Rae, Reader in the School of Earth and Environmental Science, said: “the ocean becoming more acidic poses major risks to marine ecosystems and the communities and economies they support. The solutions we now have for climate change, like heat pumps and electric vehicles, also fix ocean acidification, so it’s critical that we support them”.
Continue reading ‘Ocean in coastal areas becoming more acidic than previously thought’A century of change in the California Current: upwelling system amplifies acidification
Published 18 November 2025 Science ClosedPredicting the pace of acidification in the California Current System (CCS), a productive upwelling system that borders the west coast of North America, is complex because the anthropogenic contribution is intertwined with other natural sources. A central question is whether acidification in the CCS will follow the pace of increasing atmospheric CO2, or if climate effects and other biogeochemical processes will either amplify or attenuate acidification. Here, we apply the boron isotope pH proxy to cold-water orange cup corals to establish a historic level of acidification in the CCS and the Salish Sea, an associated marginal sea. Through a combination of complementary modeling and geochemical approaches, we show that the CCS and Salish Sea have experienced amplified acidification over the industrial era, driven by the interaction between anthropogenic CO2 and a thermodynamic buffering effect. From this foundation, we project future acidification in the CCS under elevated CO2 emissions. The projected change in pCO2 over the 21st century will continue to outpace atmospheric CO2, posing challenges to marine ecosystems of biological, cultural, and economic importance.
Continue reading ‘A century of change in the California Current: upwelling system amplifies acidification’Effects of climate change on marine ecosystems in the southeastern Pacific: multiple ocean stressors assessed through climate velocities
Published 3 October 2025 Science ClosedTags: chemistry, modeling, regionalmodeling, South Pacific
Anthropogenic climate change (CC) has triggered a cascade of impacts on marine ecosystems, often referred to as the ‘deadly trio’: warming, acidification, and deoxygenation. While these stressors will globally lead to the compression of marine habitats, their regional effects vary significantly and remain understudied. This is particularly true for the southeastern Pacific (SEP), which supports rich pelagic and benthic ecosystems closely linked to a complex seafloor featuring archipelagos and extensive seamount chains. Using model simulations from Phase 6 of the Coupled Model Intercomparison Project, this study examines future regional-scale environmental changes in the SEP. Our analysis builds on the observation that the South Pacific Ocean Gyre is among the regions experiencing the least warming globally and that the epipelagic zone within the oxygen minimum zone (OMZ) may oxygenate in the future. These conditions may promote habitat expansion, which we assess using the climate velocities for temperature, oxygen, and pH. Estimates of climate velocities from the ensemble model mean under a pessimistic near future (2015-2050) yield values ranging from –730 to 449 km/year, exhibiting greater absolute climate velocities for oxygen than pH. Over the longer-term horizon (2015–2100), the area of zones where absolute climate velocity exceeded the 75th percentile increased by 65%, 72%, and 215% for temperature, oxygen, and pH, respectively. The strongest velocities (absolute value) occur in the equatorial sector and in the Humboldt system. While all regions mostly show a climate-driven habitat loss due to surface-to-200 m pH decline, two broad areas benefit from conservation below the surface: a region in the tropics extending from 10°S–100°W to the east of Rapa Nui and the coastal region of Peru and Chile, extending up to the Desventuradas and Juan Fernández archipelagos. While the former is due to the slow warming rates (<2.9 km yr−1), the latter results from both slow deoxygenation and oxygenation climate velocities (between −2.9 and 2.9 km yr−1) along the coast of those countries, a zone that overlaps with the lowest changes in pH in the SEP, giving them a unique conservation value. We demonstrate that epipelagic ecosystems within the OMZ may be less impacted by CC than those outside of it. These findings highlight key areas for conservation under future ocean warming, deoxygenation and pH changes.
Continue reading ‘Effects of climate change on marine ecosystems in the southeastern Pacific: multiple ocean stressors assessed through climate velocities’New Jersey ocean acidification action plan
Published 3 October 2025 Science ClosedTags: mitigation, North Atlantic, policy, socio-economy
The NJDEP created an Ocean Acidification Action Plan to address ocean and coastal acidification. Left unchecked, this global issue will negatively impact the balance of the ecosystem as well as the state’s fish and shellfish industries. Shellfish are particularly vulnerable through the impacts of acidification on shell formation.
The New Jersey Ocean Acidification Action Plan identifies steps that the NJDEP has already taken that can help mitigate ocean and coastal acidification and outlines the Department’s next steps to better understand the current conditions and prepare for additional impacts of ocean and coastal acidification.
Continue reading ‘New Jersey ocean acidification action plan’Sibling species differently distributed around a CO2 vent show transplantation proteomic remodelling, while displaying metabolomic signatures associated with their origin
Published 2 October 2025 Science ClosedTags: adaptation, annelids, biological response, BRcommunity, field, Mediterranean, otherprocess, physiology, vents
The cellular homeostatic response (CHR) and cellular stress response (CSR) work together to maintain homeostasis. Studying phylogenetically closely-related species inhabiting different environments can help investigate the interplay between the CHR and CSR. We conducted reciprocal in situ transplant experiments in a natural CO2 vent (Ischia, Italy), using the sibling annelid species Platynereis cf.. dumerilii and Platynereis cf.. massiliensis which have been shown to have different preferential distributions around the CO2 vent. Following transplantations, we characterised the response of each individual’s proteome, metabolome, and lipidome, to short or long-term exposure to different pCO2 regimes (i.e., high and low), and confirmed its genetic identity. Here we show that different components of the CHR and CSR are utilised at different rates when Platynereis spp. are exposed to different pCO2 regimes, with cellular responses shown to be conserved across species. Metabolome and lipidome responses were dependent on regime of origin, and changed relatively slowly, whereas proteome responses were dependent on transplant type and changed more rapidly. Our results provide new insights to improve our understanding of the interplay between different cellular physiological responses involved in defining the functional phenotype of marine species, and their ability to acclimatise to future projected high pCO2 conditions.
Continue reading ‘Sibling species differently distributed around a CO2 vent show transplantation proteomic remodelling, while displaying metabolomic signatures associated with their origin’Une septième « limite planétaire » vient d’être franchie, « nous faisant entrer dans des conditions dangereuses » (in French)
Published 2 October 2025 Science , Web sites and blogs ClosedUn rapport scientifique conclut que la limite de « l’acidification des océans » a été franchie en 2025, menaçant « la vie marine » sur Terre.
Brett Monroe Garner / Getty Images. Une septième « limite planétaire » vient d’être franchie, la Terre est en train de devenir inhabitable. (Photo d’un champ de coraux sur la Grande Barrière de Corail lors d’un épisode de blanchissement massif.)
Créées en 2009 sous l’impulsion du scientifique suédois Johan Rockström, les limites planétaires désignent les différents points à ne pas dépasser pour garder la planète dans un état vivable. Une trentaine de chercheurs estimaient il y a quinze ans que l’humanité avait « transgressé au moins trois limites planétaires ». Depuis, les bilans annuels de l’Institut de recherche sur le climat de Potsdam (PIK) ont montré une dégradation continue.
Celui de 2025 indique que la limite de « l’acidification des océans » vient d’être franchie. « L’océan est en train de s’acidifier, menaçant la vie marine et nous faisant entrer dans des conditions dangereuses, avec une tendance qui s’aggrave encore », ont écrit ses chercheurs. En d’autres termes, ce sont tous les écosystèmes marins qui sont menacés, comme en atteste le blanchissement des récifs coralliens, phénomène annonciateur de leur mort.
Excès de CO2 et révision des calculs
La principale cause de l’acidification des océans est l’absorption de dioxyde de carbone (CO2) émis avec la combustion d’énergies fossiles. Les scientifiques estiment que les océans ont absorbé environ 30 % de l’excès de CO2 relâché dans l’atmosphère par la combustion de pétrole, de gaz et de charbon.
La hausse de l’acidification par rapport aux chiffres publiés l’an dernier est également due en partie à une amélioration des données et à une révision des calculs.
Les six autres seuils déjà dépassées concernent le changement climatique (CO2 dans l’atmosphère), l’intégrité de la biosphère (extinction d’espèces et appropriation des ressources par l’humanité), mais aussi l’usage des sols (déforestation), le cycle de l’eau douce (zones touchées par la sécheresse ou les inondations), les cycles biogéochimiques (ajout d’engrais et pesticides) et l’introduction d’entités nouvelles dans la biosphère (plastiques et autres produits chimiques industriels).
Continue reading ‘Une septième « limite planétaire » vient d’être franchie, « nous faisant entrer dans des conditions dangereuses » (in French)’Echinoderms exposed to shifting environmental conditions possess biological mechanisms that allow them to persist. These include intraspecific processes acting at different evolutionary and temporal scales: local genomic adaptations shaped by selective pressures over generations, and phenotypic plasticity expressed as individuals adjust to genotype–environment interactions during their lifetimes. The relationship between echinoderms and their symbiotic microbiota may further influence their adaptive capacity. Our group has adopted a multidisciplinary approach to examine the adaptive potential of key echinoderm species under ocean warming and acidification, combining observations along natural temperature and pH gradients with controlled laboratory experiments. We find diverse stress responses and adaptive strategies—ranging from local genomic differentiation and shifts in gene expression to metabolic adjustments—that vary between species. However, these intra- and interspecific mechanisms do not always align. Differences in evolutionary history and thermal tolerance may underpin the contrasting resilience of echinoderms, offering crucial insights into their survival prospects under future oceanographic change.
Continue reading ‘Echinoderms in a changing ocean: strategies for survival’Thermal and acidification gradients reveal tolerance thresholds in Pocillopora acuta recruits
Published 1 October 2025 Science ClosedTags: biological response, corals, laboratory, molecular biology, morphology, mortality, multiple factors, North Pacific, reproduction, temperature
Ocean warming and acidification are among the biggest threats to the persistence of coral reefs. Organismal stress tolerance thresholds are life stage specific, can vary across levels of biological organisation and also depend on natural environmental variability. Here, we exposed the early life stages of Pocillopora acuta in Kāne‘ohe Bay, Hawai‘i, USA, a common reef-building coral throughout the Pacific, to projected ocean warming and acidification scenarios. We measured ecological, physiological, biomineralisation and molecular responses across the critical transition from larvae to newly settled recruits following 6 days of exposure to diel fluctuations in temperature and pH in Control (26.8°C–27.9°C, 7.82–7.96 pHTotal), Mid (28.4°C–29.5°C, 7.65–7.79 pHTotal) and High conditions (30.2°C–31.5°C, 7.44–7.59 pHTotal). We found that P. acuta early life stages are capable of survival, settlement and calcification under all scenarios. The High conditions, however, caused a significant reduction in survival and settlement capacity, with changes in the skeletal fibre deposition patterns. Although there was limited impact on the expression of biomineralisation genes, exposure to High conditions resulted in strong transcriptomic responses including depressed metabolism, reduced ATP production and increased activity of DNA damage-repair processes, indicative of a compromised metabolic state. Collectively, our findings demonstrate that coral juveniles living in environments with large diurnal fluctuations in seawater temperature and pH, such as Kāne‘ohe Bay, can tolerate exposure to moderate projected increased temperature and reduced pH. However, under more severe environmental conditions, significant negative effects on coral cellular metabolism and overall organismal survival jeopardise species fitness and recruitment.
Continue reading ‘Thermal and acidification gradients reveal tolerance thresholds in Pocillopora acuta recruits’Genomic study uncovers resilience of coral-killing sponge
Published 1 October 2025 Press releases Closed
In the vast and intricate ecosystems of coral reefs, a hidden danger lurks, posing threats not just to the colorful corals themselves but to entire marine environments. Recent research spearheaded by Liu, PY., Chiu, WC., Lim, S.L., and their collaborators has shed light on the mysterious and pervasive sponge known as Terpios hoshinota. This sponge, infamous for its destruction of coral reefs, exhibits a remarkable ability to thrive under extreme environmental stressors, raising crucial questions about the future of coral ecosystems worldwide.
The study culminated from a comprehensive genomic analysis that aimed to unravel the underlying mechanisms behind the resilience and adaptability of T. hoshinota. As climate change continues to push marine environments to their limits, understanding how this sponge flourishes in conditions that would otherwise be detrimental to many marine organisms is not just interesting—it’s essential.
The research focuses on the genetic underpinnings that allow T. hoshinota to prosper in the face of rising sea temperatures, ocean acidification, and various pollutants. It is now well established that climate change has dire implications for marine biodiversity. The stressors these ecosystems endure can catalyze shifts that drastically alter their composition. As corals struggle, T. hoshinota capitalizes, spreading across coral reefs and frequently leading to mass coral die-offs.
One of the surprising findings of the research was that T. hoshinota possesses a unique set of genes that facilitate the breakdown of harmful substances in its environment. These genes effectively enable the sponge to withstand conditions that would typically weaken or kill other marine organisms. The genomic data indicates that this sponge has evolved sophisticated biochemical pathways, granting it a metabolic edge in nutrient acquisition even when resources are scarce.
Perhaps more alarming is the sponge’s ability to adapt rapidly to changing environmental conditions. The study highlights the sponge’s remarkable genomic plasticity, allowing for quick responses to stress. While many coral species take years or decades to make adaptations, T. hoshinota seems to have a genetic toolkit that allows for swift modifications. This adaptability could mean that the sponge will remain a dominant presence within marine ecosystems, further complicating conservation efforts targeting coral health.
Continue reading ‘Genomic study uncovers resilience of coral-killing sponge’Genomic analysis reveals broad adaptability of coral-killing sponge (Terpios hoshinota) under environmental stress
Published 1 October 2025 Science ClosedTags: biological response, laboratory, molecular biology, North Pacific, porifera
The coral-killing sponge, Terpios hoshinota, poses a significant ecological threat to coral reefs, exhibiting rapid expansion and competitive overgrowth. Despite its invasiveness, the genomic basis underlying its adaptability and resilience remains largely unexplored. Here, we present a high-quality genome assembly of T. hoshinota, comprising 169.4 Mb with 40,945 predicted genes. Phylogenomic analysis estimated its divergence from other demosponges during the Ordovician (~ 471 million years ago), even though its simple morphology suggests a more ancient evolutionary origin. Comparative genomic analyses revealed enrichment of genes related to substrate adhesion, innate immunity, and developmental pathways, including expansions of Wnt signaling, homeobox genes, and cell migration gene ontologies which may contribute to its aggressive growth and resilience. Transcriptomic responses under simulated climate stress conditions (heat stress at 31 °C and acidification at 700 ppm pCO₂) indicated dynamic gene regulation, with upregulation of neurotransmitter metabolism, cellular maintenance, and ion homeostasis responses. Despite these stressors, it remained stable. This suggests that T. hoshinota exhibits strong adaptability and resilience through rapid gene regulation. In conclusion, these findings provide molecular insights into T. hoshinota’s ecological success, its potential expansion under climate change, and its broader impact on coral reef ecosystems.
Continue reading ‘Genomic analysis reveals broad adaptability of coral-killing sponge (Terpios hoshinota) under environmental stress’Will shellfish be unable to grow in oceans of the future?
Published 30 September 2025 Press releases ClosedQuantifying the threat of ocean acidification to predict its impact on shellfish larvae
1. Key Points
- As ocean acidification worsens, concerns over its effects on calcifying organisms※1, including shellfish and coral, are increasing. To date, research has been unable to quantify the impact of ocean acidification on calcifying organisms, largely because of their incredibly small shells.
- In the present study, mollusk larvae with tiny shells measuring approximately 0.1 mm were raised in an environment designed to simulate severe ocean acidification. Subsequently, a high-resolution microfocus X-ray computed tomography (MXCT)※2 scanner was used to obtain three-dimensional measurements of the shells. For the first time, globally, changes in shell morphology, in terms of reduced shell thickness, size, and density, were quantified precisely.
- In addition, gene expression in genomic domains involved in shell formation was reduced significantly, which marks a significant step toward comprehensive understanding of the effects of ocean acidification on organisms, with respect to biological responses and the impact on shells.
- The methodology employed in the present study could also be applied to other organisms with calcified shells or skeletons, such as bivalves and corals. Such studies could facilitate environmental impact assessment, marine conservation, and fisheries resource management in future.
Fig. 1. Predicting the future using a technique to measure the shell density of shellfish larvae.
…
2. Overview
As global warming intensifies, so does ocean acidification. Such ocean acidification poses a serious threat to marine ecosystems. It not only lowers the pH of seawater but also reduces the “aragonite saturation state (Ωaragonaite)※3, ※4 ”. Aragonite is a crystalline form of calcium carbonate. When the “aragonite saturation state” is 1 or higher, it indicates a supersaturated state; conversely, values below 1 indicate an unsaturated state. The value is as an indicator of how easily organisms can form aragonite-based shells or skeletons. When the aragonite saturation state decreases, it is more difficult for organisms to form aragonite shells or skeletons. However, evaluating the effects of ocean acidification on early developmental stages of organisms such as plankton and mollusk larvae with aragonite shells, has proven challenging. Their shells are exceptionally small (approximately 0.1 mm in diameter and only a few micrometers※5 thick), which makes precise quantitative assessment more challenging than with mature specimens.
To address the challenges above, Keisuke Shimizu (Associate Researcher) and Katsunori Kimoto (Acting Group Leader) from the Japan Agency for Marine-Earth Science and Technology Research Institute for Global Change Earth Surface System Research Center, alongside Masahide Wakita (Associate Researcher, Mutsu Research Institute), carried out joint research with Takenori Sasaki (Associate Professor, University Museum at the University of Tokyo). The team analyzed the morphology of the shells of shellfish larvae, using high-resolution MXCT and scanning electron microscopy (SEM)※6, as well as gene expression. Globally, the research team is the first to successfully visualize and quantify the effects of decreased aragonite saturation on the growth and structure of extremely small shells (approximately 0.1 mm) composed of aragonite crystals, using shell density (which is analogous to human bone density) as a novel growth marker. In addition, the findings suggest that a decrease in aragonite saturation may both directly impact shells and influence gene expression domains involved in shell formation in shellfish larvae. The findings could facilitate prediction of the effects of environmental change (such as global warming and acidification) on calcifying organisms such as shellfish and corals.
These results have been published in the Journal of Molluscan Studies on September 18 (Japan time). The research was conducted with the support of a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (KAKENHI; JP23H02299).
…
Continue reading ‘Will shellfish be unable to grow in oceans of the future?’A window into the effect of ocean acidification on molluscan larval shell development using a quantitative approach
Published 30 September 2025 Science ClosedTags: biological response, laboratory, molecular biology, mollusks, morphology, North Pacific, reproduction
Increasing atmospheric CO2 levels have led to decreased pH and calcium carbonate saturation (Ω) of seawater, a process referred to as ocean acidification. Ocean acidification is expected to reduce biomineralization by marine calcifiers, such as molluscs, and many studies have reported serious effects on molluscan shell development. However, it has not previously been possible to quantitatively compare these effects on tiny structures, such as larval shells, among and within species. We applied the measurement technique of micro-focus X-ray computed tomography (MXCT) to larval shells of the limpet Nipponacmea fuscoviridis to quantitatively trace the process of shell growth (shell thickness and shell density). Shell thickness and density significantly decreased in seawater with low Ω levels. Scanning electron microscopy (SEM) revealed that the surface structure of the shell in larvae cultured under low Ω was disturbed. Gene expression analysis showed that the development of shell-forming regions under low Ω was significantly reduced. MXCT analysis can quantify mineralization in tiny larval shells; in combination with other methods such as SEM and gene expression analysis, it can provide a novel perspective in the assessment of the impact and resilience of marine calcifiers to changes in the marine environment.
Continue reading ‘A window into the effect of ocean acidification on molluscan larval shell development using a quantitative approach’Ocean acidification threatens planetary health: Interview with Johan Rockström
Published 30 September 2025 Web sites and blogs ClosedTags: interview
- The newly published 2025 Planetary Health Check report confirms transgression of the ocean acidification planetary boundary — the seventh Earth system threshold crossed, putting a “safe operating space for humanity” at risk. Oceans act as a key climate stabilizer, resilience builder and Earth life-support system.
- Marking the launch of the 2025 Planetary Health Check, Mongabay speaks with report co-author and renowned Earth system scientist Johan Rockström about how the transgression of planetary boundaries is eroding environmental justice — the right of every human being to life on a stable, healthy planet.
- Rockström, who led the international team of scientists who originated the 2009 planetary boundary framework, also speaks about the failure to achieve a U.N. plastics treaty in August and the challenge of accomplishing planetwide sustainability in a time of widespread armed conflict and political instability.
- He likewise emphasizes the need to bring the U.S. back to the negotiating table at COP30, the U.N. climate summit scheduled for November, in Belém, Brazil, and addresses the importance of inserting the planetary boundaries framework into those talks.
Initiated in 2024, the Planetary Health Check is a comprehensive, science-based global initiative dedicated to measuring and maintaining Earth systems critical to life as we know it.
These annual reports were created to provide a regular, comprehensive assessment of the state of our world, utilizing the most current planetary boundaries science — monitoring changes, gauging risks, identifying urgent actions needed, developing solutions and determining progress in maintaining a “safe operating space for humanity.”
The just-published 2025 assessment finds that seven out of the nine critical planetary boundaries (PBs) have been breached: climate change, change in biosphere integrity, land system change, freshwater change, modification of biogeochemical flows, the introduction of novel entities, and now, ocean acidification.
All of these Earth system boundary transgressions show escalating trends, threatening further deterioration and destabilization of planetary health in the near future. Just two PBs remain within the safe operating space: increase in atmospheric aerosol loading (with an improving global trend) and stratospheric ozone depletion (currently stable).
Earth System scientist Johan Rockström, director of the Potsdam Institute for Climate Impact Research (PIK) in Germany, spoke to Mongabay on the occasion of the launch of the Planetary Health Check 2025 report, which announces the transgression of the ocean acidification boundary — the seventh Earth system boundary threshold crossed, putting the safe operating space for humanity at grave risk.
PIK’s director is co-author of the 2025 report and author of the book and video documentary Breaking Boundaries: The Science of Our Planet (2021), which explains the planetary boundaries framework, which was developed in 2009 by an international scientific team led by Rockström. This framework was also the inspiration for the Frontiers Planet Prize, which awards three prizes of $1 million every year to research offering the greatest potential to address the ecological crisis.
The newly released report signals a planetary emergency requiring immediate and coordinated global action, say scientists. (This interview has been lightly edited for brevity and clarity.)
This iconic planetary boundaries (PBs) diagram visually represents the current status of the nine critical PB processes that regulate our planet’s health. Each Earth system is quantified by one or more control variables based on observational data, model simulations and expert opinions. Image courtesy of Planetary Health Check 2025.
Mongabay: The Planetary Health Check 2025 report announces the transgression of the ocean acidification boundary (the decreasing of pH in seawater caused by the absorption of atmospheric CO₂), the seventh Earth boundary threshold to be crossed due to humanity’s actions. What does this mean and why is it relevant to all of us?
Johan Rockström: The latest update — based on data observations as to where [ocean] acidification is developing, and on the refined methodology for making those observations — concludes, unfortunately, but not unexpectedly, that the ocean acidification boundary has now been breached.
This is a very worrying trend, because the ocean is under multiple planetary pressures: [including] the faster than expected heat increase, the ocean acidification boundary now being breached, continuous eutrophication, and the loss in biodiversity due to overfishing and other causes. So, we have an ocean system on planet Earth, across all marine systems, under high and increased pressure.
…
Julian Reingold, Mongabay, 24 September 2025. Full article.
Our planet’s vital signs are flashing red (text and audio)
Published 29 September 2025 Science , Web sites and blogs ClosedWe have breached 7 out of 9 Planetary Boundaries.
The Planetary Health Check 2025 makes it clear: We have to act now.
Human activities have pushed Earth beyond its Safe Operating Space. The planet’s natural resilience is weakening: global warming is accelerating, ecosystems are showing clear signs of degradation, and early warning signs of tipping points are emerging in key systems. We have entered the Anthropocene — an era where human activity dominates the Earth system.
To saveguard the Earth’s resilience and stability, we must bring the planet back into its Planetary Boundaries. These boundaries are scientifically defined guardrails that ensure the Earth’s health. Stay within them, and the Earth stays our dependable home — breach them, and we risk irreversible damage to our very own life support system. Today, seven out of nine boundaries have been transgressed.
The Planetary Health Check is a yearly report on the state of our planet. It presents the most up-to-date assessments of the Planetary Boundaries, gives thorough introductions into cutting-edge science, and spotlights especially relevant aspects of our planet’s health. In this 2025 edition, we place a special focus on the Ocean’s role in the Earth system, and assess for the first time that Ocean Acidification is the seventh transgressed Planetary Boundary.
Planetary Health Check 2025
A Scientific Assessment of the State of the Planet
This second annual assessment of our planet’s health presents the most up-to-date Planetary Boundaries science. In focus this year: our ocean, and the role it plays for earth’s stability and habitability. Further spotlights include an investigation of the last year’s extreme weather events, and a landscape overview of efforts to put Planetary Boundary science into action.
About this Project
The Planetary Boundaries Science (PBScience) project was launched in 2023 to address critical gaps in our understanding and monitoring of the Earth system. Utilizing advanced simulation modeling, incorporating the latest available measurement datasets and synthesizing new insights from Earth system science literature, PBScience provides annual Planetary Health Checks based on the Planetary Boundaries framework. Collaborating closely with the Planetary Guardians and other partners, PBScience strives to elevate global awareness and drive action towards maintaining planetary stability.
Continue reading ‘Our planet’s vital signs are flashing red (text and audio)’Une nouvelle limite planétaire a été franchie pour la première fois en 2025: l’acidification des océans. Ce processus, directement lié à nos émissions de CO2, est délétère pour les écosystèmes marins.
L’acidité des océans perturbe la reproduction, la croissance et les fonctions métaboliques de nombreuses espèces. WIKIMEDIA COMMONS
Après celle sur le cycle de l’eau en 2023, une nouvelle limite planétaire a été franchie pour la première fois en 2025: l’acidification des océans. Provoquée par nos émissions de CO2, elle vient de dépasser un seuil alarmant. C’est la conclusion centrale du rapport sur les limites planétaires publié le 24 septembre par le Planetary Boundaries Science Lab, un laboratoire allemand dépendant de l’Institut de recherche de Potsdam sur les effets du changement climatique.
La notion de limites planétaires est développée depuis 2009 par plusieurs scientifiques à la pointe des sciences du «système Terre», autour notamment du chercheur suédois Johan Rockström. Ils définissent ces limites comme autant de seuils dans des processus planétaires à ne pas franchir, au risque de déstabiliser l’ensemble du système de manière irréversible, avec des effets majeurs pour le vivant. L’humanité, entre autres, dépend depuis 12 000 ans de cette stabilité pour «vivre, grandir et prospérer en toute sécurité», répète avec insistance le rapport.
7 limites dépassées sur 9
Les signaux rouges clignotent de toutes parts. Sur neuf limites planétaires identifiées par les chercheurs, l’acidification des océans est la septième à être franchie. Les six premières (changement climatique, cycle de l’eau, biodiversité, perturbations du cycle de l’azote et du phosphore, déforestation et changement d’utilisation des sols, pollution terrestre par des milliers de substances synthétiques) sont non seulement déjà dépassées, mais leur situation continue de s’aggraver.
Seules deux limites sont respectées et ne se détériorent pas: la pollution aux aérosols atmosphériques et le maintien de la couche d’ozone.
L’acidité de l’eau à la surface de l’océan a augmenté de 30 à 40% depuis l’ère préindustrielle, alertent les auteurs du rapport. Un processus directement lié à nos émissions de gaz à effet de serre puisque l’océan a la capacité de dissoudre une partie du CO2 atmosphérique. Il est même un puits de carbone essentiel, qui absorbe environ le quart de l’ensemble des émissions anthropiques.
Revers de la médaille: ce CO2 dissout dans l’eau conduit, par une suite de réactions chimiques, à augmenter l’acidité de l’océan. Un phénomène extrêmement délétère pour les organismes marins. Beaucoup d’espèces – coraux, mollusques et certains crustacés notamment – ont de plus en plus de difficulté à fabriquer leur coquille et leur squelette lorsque l’acidité augmente.
Continue reading ‘Septième limite planétaire franchie (in French)’Mapping the knowledge domain of ocean acidification impacts on marine microbial communities: visual exploration based on citespace
Published 29 September 2025 Science ClosedTags: biological response, laboratory, molecular biology, prokaryotes, review
Ocean acidification (OA) threatens marine microbial communities that underpin global biogeochemical cycles and marine food webs, however, a systematic synthesis of research progress in this area remains limited. This study presents the first comprehensive bibliometric analysis of ocean acidification impacts on microbial ecology, analyzing 495 Web of Science publications (2005-2025) using CiteSpace to characterize the field’s evolution and identify emerging frontiers. Global collaboration spans 53 countries, led primarily by China, the United States, and Germany, with the GEOMAR Helmholtz Centre for Ocean Research prominent within institutional networks. The research focus has shifted from basic chemical parameters to complex ecosystem processes, with “responses” identified as the most active contemporary research frontier. Overall, the field has matured into a highly internationalized, interdisciplinary domain. We outline four strategic directions for future work: (1) integrating advanceds molecular technologies, including multi-omics and single-cell approaches, to resolve mechanisms; (2) expanding temporal and spatial scales through global observatory networks; (3) quantifying multiple-stressor interactions, particularly with warming and deoxygenation; and (4) connecting molecular processes to biogeochemical cycles at the ecosystem level. These findings provide a data-driven roadmap for next-generation on OA–microbe interactions, essential for predicting marine ecosystem responses to accelerating environmental change and for informing evidence-based ocean conservation policy.
Continue reading ‘Mapping the knowledge domain of ocean acidification impacts on marine microbial communities: visual exploration based on citespace’
