Summary of ocean acidification data collected by the National Coral Reef Monitoring Program in the U.S. Pacific Islands, 2021—2023

Published 10 February 2026 Newsletters and reports Leave a Comment
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Coral reefs are among the most biologically diverse and economically valuable ecosystems on earth. They provide billions of dollars annually in food, jobs, recreation, coastal protection, and other critical ecosystem services (Brander & van Beukering, 2013; Costanza et al., 2014). However, these ecosystems are also among the most vulnerable to ocean acidification (OA). Even under the most optimistic model projections, increasing atmospheric and seawater carbon dioxide concentrations are likely to occur over the next few decades, decreasing seawater pH and reducing the availability of the carbonate ion (CO32-) building blocks that corals and other marine calcifiers use to construct reef habitat (Chan & Connolly, 2013; Jiang et al., 2023). OA threatens the persistence of coral reefs by reducing rates of coral and crustose coralline algae (CCA) calcification and accelerating rates of bioerosion, thereby lowering net production of calcium carbonate (CaCO3) and compromising the structural complexity and integrity of three-dimensional reef habitat (Cornwall et al., 2021; Hill & Hoogenboom, 2022). As a result, many of the ecological, economic, and cultural values offered by coral reefs could be significantly impacted by OA over the next century.

NOAA’s National Coral Reef Monitoring Program (NCRMP) provides a framework for long-term, national-level monitoring of the U.S.-affiliated coral reef areas. Funded jointly by the NOAA Coral Reef Conservation Program and Ocean Acidification Program, NCRMP assesses the status and trends of U.S. coral reef ecosystems and supports the management of the nation’s reefs (NOAA Coral Program, 2021). NCRMP’s long-term monitoring of OA and related coral reef ecosystem responses (NCRMP-OA) evaluates patterns and trends in carbonate chemistry and key ecosystem indicators across gradients of biogeography, oceanographic conditions, habitat types, and human impacts. These data sets are used to inform the efficacy of place-based coral reef management in close collaboration with federal, state, and jurisdictional partners.

To assess the progression of OA and impacts on coral reef ecosystems in the U.S. Pacific Islands, NCRMP-OA monitoring includes the following objectives:

  • Conduct carbonate chemistry sampling to monitor spatial variability and temporal change in pH, aragonite saturation state (Ωar), and other carbon system parameters;
  • Conduct diel carbonate chemistry water sampling and oceanographic instrument deployments at select sites;
  • Conduct census-based carbonate budget assessments to estimate rates of coral reef biological carbonate production and erosion.

This report summarizes the monitoring effort and results from 2021–2023 NCRMP-OA sampling and surveys. Additional NCRMP environmental, benthic, and fish data are not included in this report, but they can be accessed at the links provided in the Data Availability section.

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Microbial community dynamics over large spatial and environmental gradients in a subtropical ocean basin

Published 9 February 2026 Science Leave a Comment
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Microbes are fundamental to ocean ecosystem function, yet they remain understudied across broad spatial and environmental scales in dynamic regions like the Gulf of America/Gulf of Mexico (GOM). We employed DNA metabarcoding to characterize prokaryotes (16S V4–V5) and protists (18S V9) across 51 stations, spanning 16 inshore–offshore transects and three depths. Cluster analysis revealed three clusters corresponding to depth zones that integrated vertical and horizontal sampling: photic zone (inshore near surface–bottom and offshore surface), deep chlorophyll maximum (offshore), and aphotic zone (offshore near bottom). We applied group-specific generalized additive models (GAMs) to log-transformed abundance data of major taxa in the photic zone, identifying key environmental factors that explained 42%–82% of the variation in abundance. SAR11 and SAR86 were positively associated with temperature and dissolved inorganic carbon, while cyanobacterial genera (Prochlorococcus and Synechococcus) were differently impacted by nutrients, salinity, and pH in ways that often followed their expected ecological niches. Representatives of protist parasites (Syndiniales) and grazers (Sagenista) showed group-specific nonlinear associations with salinity, oxygen, nutrients, and temperature. Using GAMs, we expanded the spatial resolution of DNA sampling and predicted surface log abundances at 84 cruise sites lacking amplicon data. Indicator analysis was performed with sequence-level data, revealing several protists that were indicative of more acidic waters and the absence of any significant prokaryote indicators. Our results provide the first basin-scale survey of microbes in the GOM and highlight the need for coordinated omics and environmental sampling to improve predictions of microbial responses to changing conditions.

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Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates

Published 6 February 2026 Science Leave a Comment
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Over the past 50 years, the oceans have absorbed over 90% of global warming heat, leading to warming, acidification, and declining oxygen levels that are disrupting marine ecosystems and altering species distributions and productivity. The vulnerability of marine organisms to these changes depends on their biological traits, habitat conditions, and adaptive capacity, influencing their growth, behavior, and overall population health. Micro-computed tomography (micro-CT) has been previously used for studying the morphological traits of marine invertebrates, which provide important insights into species functionality and responses to climate change and ocean acidification. Micro-CT enables non-destructive, high-resolution 3D analysis of internal and external structures, allowing precise measurement of traits such as density, porosity, and morphology that are valuable for climate change research.

The present manuscript describes micro-CT imaging datasets generated to investigate the effects of climate change on the morphological structure of two low-motility benthic marine invertebrates: the gastropod Hexaplex trunculus and the sponge Chondrilla nucula. Both species are considered particularly vulnerable to environmental stressors. To date, no study has investigated the effects of ocean warming and acidification on sponges using micro-CT technology. Using a common garden experimental design, individuals from geographically distinct populations exposed to different natural environmental regimes were subjected to combined warming and acidification scenarios to assess their morphological responses and adaptive capacity.

Continue reading ‘Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates’

Untargeted mass spectrometry to investigate ocean acidification in Cancer borealis using optimized metabolite extraction methods

Published 5 February 2026 Science Leave a Comment
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Ocean acidification (OA) refers to the ongoing decline in ocean pH caused by the cascading effects of increased atmospheric CO2, which has significant negative impacts on various marine organisms, particularly crustaceans with calcified shells. However, research on the metabolic responses of crustaceans remains limited. In this study, we performed untargeted metabolomics on hemolymph samples from Cancer borealis (Jonah crab), a crustacean species well known for its tolerance to temperature and pH changes, to investigate its metabolic responses to OA. Two extraction methods—isopropanol (IPA) and acidified methanol (AcMeOH)—were employed to capture a broad range of metabolites and small peptides. Both methods enabled comprehensive detection; however, IPA yielded more consistent and extensive metabolite coverage, identifying 43 lipids compared to only 15 with AcMeOH. We identified 15 metabolites that responded significantly to OA. Several metabolites, including the potential neuropeptide cycloprolylglycine and the exogenous compound curcumin, exhibited concentration changes under OA exposure, suggesting their potential relevance in stress response pathways triggered by environmental stress. Overall, we highlight IPA as a more effective extraction method for untargeted metabolomics in crustacean hemolymph. Our study elucidates metabolic dynamics that enhance our understanding of the physiological adaptability of marine crustaceans under environmental stress and provides a comprehensive dataset that for future OA research.

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Apply now: GCAN student workshop

Published 5 February 2026 Events Leave a Comment

GCOOS and Gulf of America Coastal Acidification Network (GCAN) are seeking to support the next generation of leaders in ocean and coastal acidification in the Gulf states by inviting applications to a dedicated workshop on ocean and coastal acidification (OA/COA). The workshop will focus on teaching students how to transform ocean and coastal acidification science into management and policy solutions.

Through this award, GCOOS will welcome a cohort of Gulf-region graduate students to attend the GCOOS Spring Meeting, the GCOOS 20th Anniversary celebration and allow them to participate in the workshop. Students will engage with scientists, managers, industry and educators during this event.

The full program of activities will be shared with the awardees prior to the meeting, but the workshop will include technical skills training, GCOOS Board Members’ panel and campus tour.

During the workshop, students will present at a poster session during the GCOOS Spring Members’ meeting & anniversary celebration on April 14, 2026, then join the GCAN workshop April 15 and 16. The workshop’s first day will focus on a technical core with applied tools in ocean acidification led by the GCAN steering committee chair, followed by a panel with GCOOS Board Members and then a working session designed to help students translate posters into a two-minute briefing for resource managers, stakeholders and general audiences using plain-language messaging. The final day will conclude with recording video summaries of the students’/postdoctoral researchers’ experience and tour of the Texas A&M campus.

Student Eligibility Requirements

  • Currently enrolled in a graduate program or working as a year 1-3 postdoctoral researcher at institutions in Florida, Alabama, Mississippi, Louisiana or Texas;
  • Be authorized to fly to College Station, Texas, to attend the meeting in person (i.e., visa is up to date);
  • Have an interest in management, policy and/or research related to ocean and coastal acidification issues.

Student Responsibilities

  • Attend full meeting in person (April 14-18, 2026);
  • Present a poster on current work relevant to OA/COA or closely linked stressors (e.g., hypoxia, eutrophication, HABs, carbonate chemistry variability);
  • Participate actively in the GCAN workshop and contribute to a short cohort deliverable (manager-ready synthesis, shared resource list, or student priority questions).

Application Deadline

  • 11:59 p.m. CT Friday, Feb. 27, 2026

Application

Submit one combined PDF via THIS FORM with:

  • Letter of intent (max 2 pages) that describes your interest in attending the GCOOS Spring Members’ Meeting and GCAN Workshop, how your interest fits with Gulf of America Ocean and Coastal Acidification needs, learning goals, and how you will apply outcomes;
  • Poster abstract (max 300 words) with title, authors/affiliations, and summary;
  • CV (max 2 pages);
  • Advisor support letter (1 page recommended) that confirms good standing and availability to travel.
Continue reading ‘Apply now: GCAN student workshop’

OA-ICC bibliographic database updated

Published 4 February 2026 Science Leave a Comment

An updated version of the OA-ICC bibliographic database is available online.

The database currently contains 9,726 references and includes citations, abstracts and assigned keywords. Updates are made every month.

The database is available as a group on Zotero. Subscribe online or, for a better user experience, download the Zotero desktop application and sync with the group OA-ICC in Zotero. Please see the “User instructions” for further details.

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Ocean acidification, hypoxia, and harmful algal Bbloom solicitation now open – letters of intent due March 6, 2026

Published 4 February 2026 Jobs Leave a Comment
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OPC is pleased to announce the release of a California Climate Investments solicitation: Monitoring, Research, and Modeling to Support Ocean Acidification, Hypoxia, and Marine Harmful Algal Bloom Management in California. Projects should enhance scientific understanding of ocean acidification and hypoxia (OAH) and/or marine harmful algal blooms (HABs) to advance the State’s response related to these two growing threats to California’s coastal ecosystems and communities.

The solicitation will support projects that will strengthen California’s capacity to track, assess, and address the impacts of OAH on marine biota and ecosystems (Track 1); as well as support state management actions to prevent, mitigate, and control the impacts of HABs (Track 2). More detailed research priorities can be found in the solicitation.

Upcoming events & important dates:

OPC staff will be hosting a public webinar about the solicitation on Tuesday, February 10, 2026 from 2:00 p.m. to 3:00 p.m. Learn about solicitation priorities, timeline, and application process.

Register for the Webinar

Join OPC staff for office hours on Thursday, February 12, 2026 from 1:00 p.m. to 2:00 p.m. Applicants will have the opportunity to ask questions and receive guidance ahead of the upcoming deadlines.

Register for the Office Hours

Submit a Letter of Intent 

Letters of intent (LOI) are due Friday, March 6, 2026 by 5:00 p.m. LOI applicants invited to submit a full proposal will be notified by April 13. Full proposals are due Friday, June 12, 2026 by 5:00 p.m. (only applicants who have submitted an LOI may submit a full proposal). See the solicitation for the full timeline.

Contact

For more information, please contact Kyla Kelly, OPC Water Quality Program Manager (kyla.kelly@resources.ca.gov) with the subject line “OPC OAH/HABs solicitation”.

Continue reading ‘Ocean acidification, hypoxia, and harmful algal Bbloom solicitation now open – letters of intent due March 6, 2026’

New ocean sensors could transform how scientists track the marine carbon cycle

Published 3 February 2026 Web sites and blogs Leave a Comment
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The world’s oceans do far more than support vital marine ecosystems and provide food and recreation. They help regulate the Earth’s climate, absorbing vast amounts of heat and CO2, acting as one of the planet’s most important buffers against climate change.

Yet despite this vital role, scientists still struggle to track exactly how and where the ocean absorbs and stores CO2 – and how that process is changing.

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Rintala is leading an international team that aims to extend ocean observing capacity by developing sensors for platforms that can operate beyond normal shipping routes and deep below the surface – far from ships and human intervention

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At the heart of the effort is the development of the world’s first autonomous sensor capable of accurately measuring total alkalinity in the ocean – from the sea floor to the surface.

Total alkalinity is a key chemical indicator that scientists use to understand the ocean carbon system and estimate how much CO2 seawater can absorb and store.

It is also critical for tracking ocean acidification – a process driven by rising CO2 levels that lowers seawater pH and threatens marine ecosystems, particularly shell-building plankton and molluscs.

“Ocean acidification is very harmful for many marine organisms,” said Rintala. “It can cause cascading effects that ripple up the food web.”

Until now, total alkalinity has usually been measured by collecting fixed seawater samples from ships and analysing them later in onshore laboratories. That approach provides valuable data, but only at isolated points in time and space.

“If we are interested in the carbon content of the ocean as a whole, we need to measure deeper,” said ocean scientist Socratis Loucaides, based at the UK’s National Oceanography Centre (NOC).

Loucaides and his colleagues at NOC are leading the development of a radically different approach: a compact lab-on-a-chip sensor that performs a miniature chemistry experiment inside the instrument itself.

Inside the device, a small seawater sample is mixed with an acid of known strength and a dye that changes colour depending on acidity. A light-based sensor then reads those colour changes to calculate the alkalinity of the surrounding seawater.

By doing this directly in the deep ocean, the sensor can build up a far more detailed picture of how carbon is stored and transported over time – and potentially reveal early warning signs of change.

Continue reading ‘New ocean sensors could transform how scientists track the marine carbon cycle’

Resilience of the macroalgae Gongolaria barbata under ocean acidification: physiological responses and restoration perspective

Published 3 February 2026 Science Leave a Comment
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The increasing CO2 concentration is a major cause of the climate change phenomenon. Concurrently, the same increase is leading to ocean acidification (OA), which is projected to decrease seawater pH by 0.4 units by 2100. Here we investigated the potential impacts of OA on the canopy-forming brown macroalga Gongolaria barbata from the Venice Lagoon. One-year-old individuals were maintained in mesocosms under two pH levels: 8.1 (current ambient value) and 7.7 (the end-of-the-century value predicted under the current scenario of anthropogenic CO2 emissions). The physiological responses of the algae were assessed during the experiment in terms of oxygen production and consumption, and maximal PSII photochemical efficiency. At the end of the experiment, we analyzed the percentage of mature receptacles, algal growth rate and the total polyphenolic content and antioxidant capacity as indicators of the stress response. The significant decrease in polyphenolic content indicates the impairment of the defence mechanisms, which could make the algae more vulnerable to grazing under acidified conditions. Yet, conversely, our results suggest that changes in pH levels do not significantly affect the physiological processes, growth or fertility of the algae. These findings suggest that while OA may weaken defence mechanisms, the preservation of physiological and reproductive functions would still support the potential of G. barbata populations from the Venice Lagoon to act as donor sources for restoration efforts, highlighting their resistance to the acidified conditions expected in the future.

Continue reading ‘Resilience of the macroalgae Gongolaria barbata under ocean acidification: physiological responses and restoration perspective’

Ocean acidification and hypoxia research webinar

Published 3 February 2026 Events Leave a Comment
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Date – Wednesday, February 11, 2026 | 10:00 AM to 12:00 PM
Location – Virtual Event
Contact – Tanya Torres | tatorres@ucsd.edu

Register

OPC and California Sea Grant provided $2.5 million to fund three research projects addressing ocean acidification and hypoxia (OAH) in coastal California. These projects were selected though a competitive research call to address OAH research, monitoring, and synthesis priorities. Click here for more information about these projects.

Furthermore, OPC funded the Southern California Coastal Water Resource Project (SCCWRP) to expand and integrate biological measurements into ongoing OAH monitoring programs. Results from these four projects will ultimately provide state resource management agencies and local jurisdictions with data necessary to protect marine biodiversity and water quality, advance coastal adaptation efforts, and support climate-ready fisheries.

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Parental exposure to ocean acidification impacts the larval development and transcriptome of the Pacific oyster Crassostrea gigas

Published 2 February 2026 Science Leave a Comment
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Atmospheric carbon dioxide (CO2) levels are escalating at an unprecedented rate, leading to the phenomenon of ocean acidification (OA). Parental exposure to acidification has the potential to enhance offspring resilience through cross-generation plasticity. In this study, we analyzed larval growth and transcriptomic profiles in the Pacific oyster, Crassostrea gigas, a species of significant ecological relevance, under both control and elevated CO2 conditions experienced by their parental generation. Our findings indicate that the oyster populations exposed to OA exhibited a higher incidence of abnormalities during the D-shaped larval stage, followed by accelerated growth at the eyed stage. Through a comparative transcriptomic investigation of eyed larvae (25 d after fertilization), we observed that parental exposure to OA substantially influenced the gene expression in the offspring. Genes associated with lipid catabolism and shell formation were notably upregulated in oysters with parental OA exposure, potentially playing a role in cross-generational conditioning and conferring resilience to OA stressors. These results underscore the profound impact of OA on oyster larval development via cross-generational mechanisms and shed light on the molecular underpinnings of cross-generation plasticity.

Continue reading ‘Parental exposure to ocean acidification impacts the larval development and transcriptome of the Pacific oyster Crassostrea gigas’

Register for webinar: ocean acidification & marine carbon dioxide removal (mCDR)

Published 2 February 2026 Events Leave a Comment

🗓 February 18, 2026
⏰ 10:00 AM EST / 4:00 PM CET
🔗 Registration Link: https://lnkd.in/ebYA5T86

Join us for a timely discussion with OA Alliance members and partners.

As governments are being asked about marine carbon dioxide removal as part of broader climate strategies, clear guidance is needed to understand how mCDR intersects with ocean acidification.

On February 18, 2026, OA Alliance will release and discuss new support materials designed to help government members:
💧Navigate the links between mCDR and ocean acidification
💧Understand the current state of the science
💧Discuss desired outcomes, risks, and capacity needs related to mCDR strategies

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Photoaged microplastics disrupt the response of marine medaka (Oryzias melastigma) to ocean acidification: perspectives from energy metabolism and ammonia production

Published 2 February 2026 Science Leave a Comment
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Ocean acidification (OA) and microplastics (MPs, <5 mm) are co-occurring stressors that threaten marine ecosystems. Although the marine environment contains multiple pollutants, OA can alter the environmental behavior of MPs, influencing their toxicity and environmental fate. Therefore, investigating the interactive effects of OA and MPs is essential. Fish can activate physiological compensatory mechanisms to adapt to OA; however, it remains unclear how MPs affect these mechanisms. In this study, marine medaka were exposed to acidified seawater (pH 7.70) containing environmentally relevant concentrations of MPs (0.1 mg/L) for 90 days to investigate the disruptive effects of MPs on responses to OA. The results showed that while OA triggered compensatory energy metabolism reprogramming to enhance ammonia production, MPs disrupted this process, reducing the TCA cycle intermediate α-ketoglutarate. This α-ketoglutarate deficiency limited the glutamate supply for ammonia production. Simultaneous inhibition of glutamate dehydrogenase activity further limited glutamate availability. As a result, MPs reduced the level of ammonia production by 25.29%, compromising the ability to neutralize excess H+. Crucially, photoaging exacerbated this toxicity, leading to a 32.04% reduction in ammonia production. This study demonstrates that MPs interfere with fish responses to OA via α-ketoglutarate-mediated metabolic reprogramming, highlighting a vulnerability in marine organisms facing climate change scenarios.

Continue reading ‘Photoaged microplastics disrupt the response of marine medaka (Oryzias melastigma) to ocean acidification: perspectives from energy metabolism and ammonia production’

Effectiveness and scalability of coastal nature-based solutions under climate impact drivers: a systematic review

Published 30 January 2026 Science Leave a Comment
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Highlights

  • A structured review filters 117 coastal NbS studies to 35 CID-relevant and 14 implementation-informative cases
  • Coastal NbS are evaluated through their implementation components under multiple climate impact drivers
  • NbS foundational and measurement processes dominate reviewed NbS practices, while learning, governance, and economic processes remain weak
  • Scalability emerges from processes completeness rather than ecosystem type or NbS intervention design
  • Key implementation gaps are identified that limit the resilience, transferability, and policy uptake of coastal NbS

Abstract

Nature-based Solutions (NbS) are increasingly promoted for enhancing coastal resilience to climate change, yet most evaluations focus on biophysical outcomes while overlooking the project-level processes that influence long-term effectiveness and scalability. This study applies an implementation-based analytical framework to assess how coastal NbS respond to multiple Climate Impact Drivers (CIDs), including sea-level rise, ocean warming, storm intensity, precipitation variability, and ocean acidification.

A structured qualitative review of 117 coastal NbS studies was conducted, of which 35 were CID-relevant and only 14 contained sufficient process-level information for detailed analysis. Eight Implementation Components (ICs)—baseline assessment, stakeholder engagement, comparative analysis, economic analysis, performance indicators, monitoring, adaptive management, scalability and replicability—were identified and analysed using Jaccard similarity indices to quantify their co-occurrence. These ICs are related to implementation planning, governance, monitoring, learning, and scalability. The ICs were further mapped to the International Union for Conservation of Nature (IUCN) Global Standard for NbS to evaluate their conceptual alignment with recognised quality criteria.

Results show that ICs such as baseline assessment, monitoring, and performance indicators dominate current NbS practice, whereas learning-orientated and enabling processes—particularly comparative analysis, adaptive management, stakeholder engagement, and economic assessment—are weakly integrated. This structural imbalance limits cross-site learning, adaptive capacity, and scalability under interacting climate pressures. NbS interventions exhibiting more complete process architectures demonstrate greater alignment with IUCN criteria related to governance, feasibility, and long-term sustainability.

The study demonstrates that scalability is an emergent property of process completeness rather than a function of ecosystem type or intervention outcomes. This study establishes a quantitative-conceptual framework that integrates CIDs, ICs, and NbS standards, offering a transferable methodology for identifying implementation deficiencies and enhancing the design of resilient, policy-relevant coastal NbS.

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Understanding coral health from reactor engineering perspective: multiphysics modeling of coral–environment interactions

Published 30 January 2026 Science Leave a Comment
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Coral, as a bioreactor, has to continuously interact with surrounding environment to maintain a healthy state. A multi-physics reaction engineering model has been developed to capture this interaction. The coral interior is modeled as interconnected reaction units respectively for photosynthesis, respiration, and calcification, whose reaction kinetics are influenced by environmental fluctuations. Coupling between coral and environment is realized by bi-directional mass transfer at the coral-seawater interface, with consideration of the unique flow fields induced by ciliary beating. By resorting to this comprehensive model, we discover that ciliary beating demonstrates distinctively different diurnal and nocturnal functions. During daytime, beating can help reduce photosynthetic oxygen accumulation to prevent hyperoxia-induced mortality, while enhancing carbon dioxide uptake efficiency to promote nutrient production. At night, however, beating promotes oxygen acquisition for adequate respiration, while expelling carbon dioxide to inhibit symbiotic destruction under acidic stress. The model further enables mechanistic analysis of the detrimental impact of climate change on coral health, where the influences from two key factors (i.e., temperature and CO2 level) can be decoupled. It’s interesting to find out that the elevated temperature plays a dominant role during daytime, while at night the coral is dominantly influenced by rising CO2 level.

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Triple threat: ocean acidification, warming, and hyposalinity synergistically weaken shell integrity in a Mediterranean calcifying mollusk

Published 30 January 2026 Science Leave a Comment
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Highlights

  • OA, OW, and hyposalinity drive skeletal and mineralogical responses in a Mediterranean clam.
  • Combined stress makes shells less dense, more porous, and more fracture-prone.
  • Microstructural changes reveal early calcification impairments under triple stress.
  • Triple-stressor synergy compromises shell integrity and threatens fishery species resilience.

Abstract

Anthropogenic climate change is rapidly altering marine environments primarily through ocean warming, acidification, and hyposalinity, posing significant challenges for marine calcifying organisms. This study investigated the short-term effects of these stressors on the Mediterranean bivalve Chamelea gallina, a key fishery species in the Adriatic Sea, by integrating skeletal, mechanical, and mineralogical responses. Adult clams of commercial size were exposed for 21 days to eight experimental treatments manipulating two levels of temperature (18 °C vs. 22 °C), pH (8.0 vs. 7.9), and salinity (35 vs. 32), chosen to reproduce near-future climate projections and the freshwater-driven variability typical of the Adriatic Sea. Despite the short exposure duration, the combined exposure to low pH, high temperature, and reduced salinity weakens the shell of Chamelea gallina at multiple levels, compromising shell integrity, by making shells less dense, more porous, more fragile, and more susceptible to fracture, and increasing mortality. Microstructural analysis revealed smaller aragonite crystallites and lower calcium content, indicative of early impairments in the calcification process. The study highlights the occurrence of synergistic effects among stressors and reveals the vulnerability of Chamelea gallina to near-future ocean conditions, with potential cascading consequences for ecosystem functioning and fishery sustainability, given the species’ key ecological role and commercial relevance in the Adriatic Sea.

Continue reading ‘Triple threat: ocean acidification, warming, and hyposalinity synergistically weaken shell integrity in a Mediterranean calcifying mollusk’

How oysters are impacted by environmental conditions and farming practices

Published 29 January 2026 Web sites and blogs Leave a Comment
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The Rhode Island aquaculture industry is more robust than ever. The value of aquaculture products was $8,795,493 in 2024 and 89 active aquaculture farms covered 392.5 acres, according to a report by the Rhode Island Coastal Resources Management Council.

Eastern oysters account for approximately 99% of the state’s aquaculture production, the report noted. Jacqueline Rosa, who is pursuing her master’s degree in oceanography from GSO, spent 18 months conducting field work on how water quality and farming practices impact these mollusks.

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Jacqueline Rosa (center) uses a water quality sensor to measure key parameters, including temperature, salinity, and pH during weekly sampling at Wickford Oyster Company in 2024. Rosa is accompanied by oyster farmers John McKillop (left) and Kevin Tuttle. (Photo courtesy of Gage Whilden)

To examine the environmental conditions, Rosa deployed two sensors at Wickford Oyster Company’s 4-acre farm in May 2024, one at the surface of the water and one at the bottom of the water column.

Rosa revisited the farm each week to collect water samples from the surface and the bottom. She brought the samples to the Ocean Carbon Laboratory at the Graduate School of Oceanography for analysis.

“I tested the samples for pH, salinity, alkalinity, and dissolved inorganic carbon,” said Rosa, who is from Newtown, Connecticut. “These carbonate chemistry parameters help us understand trends in ocean acidification and how changing conditions may impact calcifying organisms. Shifts in carbonate chemistry can influence shell formation, growth rates, and survival, particularly during early-life stages, making these measurements critical for understanding potential stressors for farmed oysters.”

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Short-term tolerance to ocean acidification of the sub-antarctic sea-urchin arbacia dufresnii

Published 29 January 2026 Science Leave a Comment
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The accumulation of anthropogenic CO2 in the ocean is impacting the carbonate system chemistry in seawater, particularly in polar regions. Acidified seawater can impair the echinoderms internal regulation of pH due to an increase in hydrogen ions concentration, potentially affecting growth, and calcification, among other physiological activities. The goal of this work was to assess the effects of Ocean Acidification (OA) on Arbacia dufresnii, a sub-Antarctic sea urchin species. Adult specimens were exposed to three pH treatments: 7.4, 7.7, and 8.0 (control), for 21 up to 23 days. We assessed spine regeneration, a proxy of calcification, by cutting spines at the base of the shaft and evaluating the magnesium content, height, and weight of the regenerated part. The coelomic fluid was sampled for pH assessment and magnesium and calcium content analysis. The RNA/DNA ratio, a proxy of metabolic activity, was assessed in the gonads and body walls. The spine regenerated weight was significantly correlated to regenerated height but not to treatments. The coelomic fluid pH (6.77 ± 0.34) did not differ between treatments (pANOVA = 0.15). No significant differences were observed between treatments regarding RNA/DNA ratio in both body wall (pANOVA = 0.65) and gonads (pKruskal-Wallis = 0.34), the spine regenerated height (pANOVA = 0.35) and Mg regenerate content (pANOVA = 0.58). Our results suggest that A. dufresnii owns physiological mechanisms to cope with OA conditions during short-term exposure.

Continue reading ‘Short-term tolerance to ocean acidification of the sub-antarctic sea-urchin arbacia dufresnii’

Ocean acidification effects on growth, survival and physiological immunity of farmed Larimichthys crocea

Published 29 January 2026 Science Leave a Comment
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Ocean acidification has become a significant global ecological issue, particularly in coastal regions with intensive aquaculture. Fish farming is a crucial component of global food security, yet research on the impact of acidification on the aquaculture performance of economically important teleosts remains limited. In this study, we reared the fast-growing large yellow croaker (Larimichthys crocea) for 30 days under three different pH conditions: severe acidification (LA, pH 7.4), moderate acidification (MA, pH 7.8), and control (HA, pH 8.1). We comprehensively evaluated growth performance, survival rate, tissue structure, antioxidant enzyme activity, and innate immunity. The results showed that the LA group exhibited suppressed growth (significantly lower than the MA group, p < 0.05), elevated cortisol and T4 levels (p < 0.05), and trends of reduced antioxidant enzyme and innate immune enzyme activities, along with organ-specific pathological changes (vacuolation, structural loosening) in gills, liver, kidneys, and intestines, though most indices showed no significant difference from the HA group. Notably, the MA group showed optimal growth performance, stable physiological and immune responses. In conclusion, while acidification did not markedly affect the survival rate of L. crocea, severe acidification (pH 7.4) induces stress responses and tissue damage. These findings suggest that L. crocea exhibits a certain degree of tolerance to the acidification conditions tested, as several physiological parameters were not significantly affected. However, when considering the overall set of observations, including histological alterations across multiple tissues and changes in plasma and tissue parameters, long-term exposure to severe acidification (pH 7.4) appears to induce tissue damage and stress-related physiological disturbances, indicating potential health risks. This study provides empirical evidence regarding the potential risk posed by projected ocean acidification on L. crocea aquaculture and supports the development of climate change adaptation strategies for coastal mariculture.

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Y/Ho ratios in marine sediments unveil Neoproterozoic ocean acidification

Published 28 January 2026 Science Leave a Comment
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Understanding Precambrian seawater pH is critical for unraveling Earth’s early marine environments and biospheric evolution. Yet, quantitative constraints remain elusive due to the lack of robust proxies. Here, we demonstrate that yttrium/holmium (Y/Ho) fractionation during adsorption onto marine sediments serves as a novel and reliable pH proxy. Experimental results reveal that Y/Ho fractionation in ferruginous sediments follows a pH-dependent power-law relationship, while in argillaceous sediments, it is jointly controlled by pH and salinity at low salinities (< 29‰) but stabilizes (KdY/Ho ≈ 0.4) at higher salinities (≥ 29‰). Temperature exerts a negligible influence, ensuring broad applicability across geological timescales. Leveraging these relationships, we develop a quantitative method to reconstruct paleo-seawater pH using Y/Ho ratios from coexisting ferruginous and argillaceous sediments. Validation against modern and Phanerozoic records confirms the proxy’s accuracy (e.g., pH 8.21 ± 0.22 for modern Pacific sediments). Application to Neoproterozoic meta-pelites and iron formations reveals prolonged oceanic acidification (pH 5.9–6.4), deviating from previous model-based neutral-to-alkaline estimates. This acidic state, likely sustained by CO2 outgassing from carbonatite-alkaline volcanism during Rodinia’s breakup, challenges conventional views of Precambrian ocean chemistry. Our findings provide a transformative tool for probing early Earth’s environmental dynamics and highlight the interplay between tectonics, magmatism, and marine pH evolution.

Continue reading ‘Y/Ho ratios in marine sediments unveil Neoproterozoic ocean acidification’

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