Applications open: fourth winter school on ocean acidification and multiple stressors

Published 20 October 2026 Events Closed

Dates: 30 November – 11 December 2026

Location: IAEA Marine Environment Laboratories, Monaco.

Deadline for application through InTouch+ platform: 6 November 2026

The Winter School is organized by the IAEA OA-ICC in partnership with the Prince Albert II of Monaco Foundation through the OACIS Initiative (Ocean Acidification and other ocean Changes – Impacts and Solutions) and the Laboratoire d’Océanographie de Villefranche (LOV).

Introduction

Ocean acidification is a global environmental stressor that threatens marine life and the livelihoods of coastal communities. Ocean acidification is caused by increasing atmospheric carbon dioxide being absorbed by the ocean, resulting in changes to seawater carbonate chemistry, including a drop in pH. Due to global concerns about its consequences, ocean acidification is included in international policies such as Target 3 of UN Sustainable Development Goal (SDG) 14 and Target 8 of the Global Biodiversity Framework (GBF).

The IAEA’s Ocean Acidification International Coordination Centre (OA-ICC) supports IAEA Member States to minimize and adapt to OA and report towards SDG 14.3 and the GBF, with a strong focus on building capacity to study ocean acidification and related stressors and promoting international collaboration and coordination.

Ocean acidification is not happening in isolation, but in combination with other human-driven pressures, including pollution, warming, and oxygen loss. The impact of multiple ocean stressors on marine life and ecosystem function is not well understood, yet this information is crucial to inform adaptation strategies that might minimize negative effects on organisms, ecosystems, and associated socioeconomic benefits.

The Fourth Winter School on Ocean Acidification and Multiple Stressors is part of the capacity building program of the OA-ICC.  This two-week training course will provide participating scientists with a thorough understanding about key concepts and experimental design used to study the impacts of ocean acidification in the context of additional stressors.

Objectives

The aim of the Winter School is to train early-career scientists who already have experience researching ocean acidification on how to study acidification in the context of other co-occurring stressors. Through lectures and practical exercises in the laboratory, the students will gain understanding of key concepts in multiple-stressor research (e.g., What is a stressor? What is a mode of action? What is an interaction?), purposeful experimental design, and analysis of complex datasets. During the course, participants will collaborate on a joint laboratory experiment to elucidate the effects of three simultaneous drivers on marine organisms.

Target Audience

The course is open to 10-12 trainees. Priority will be given to early-career scientists with experience in marine environmental change with a focus on ocean acidification; a background in biological sciences is preferred. At least one publication in the field of marine environmental change is required.

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Participation and Registration

All persons wishing to participate in the event have to be designated by an IAEA Member State or should be members of organizations that have been invited to attend.

In order to be designated by an IAEA Member State or invited organization, participants are requested to submit their application via the InTouch+ platform (https://intouchplus.iaea.org) to the competent national authority (Ministry of Foreign Affairs, Permanent Mission to the IAEA or National Atomic Energy Authority) or organization for onward transmission to the IAEA by 6 November 2026, following the registration procedure in InTouch+:

1. Access the InTouch+ platform (https://intouchplus.iaea.org):

  • Persons with an existing NUCLEUS account can sign in to the platform with their username and password;
  • Persons without an existing NUCLEUS account can register here.

2. Once signed in, prospective participants can use the InTouch+ platform to:

  • Complete or update their personal details under ‘Complete Profile’ and upload the relevant supporting documents;
  • Search for the relevant event under the ‘My Eligible Events’ tab;
  • Select the Member State or invited organization they want to represent from the drop-down menu entitled ‘Designating Authority’ (if an invited organization is not listed, please contact InTouchPlus.Contact-Point@iaea.org);
  • If applicable, indicate whether a paper is being submitted and complete the relevant information;
  • If applicable, indicate whether financial support is requested and complete the relevant information (this is not applicable to participants from invited organizations);
  • Based on the data input, the InTouch+ platform will automatically generate the Participation Form (Form A) and/or the Grant Application Form (Form C);
  • Submit their application.

Once submitted through the InTouch+ platform, the application, together with the auto-generated form(s), will be transmitted automatically to the required authority for approval. If approved, the application, together with the applicable form(s), will automatically be sent to the IAEA through the online platform.

NOTE: The application for financial support should be made, together with the submission of the application, by 6 November 2026.

For additional information on how to apply for an event, please refer to the InTouch+ Help page. Any other issues or queries related to InTouch+ can be sent to InTouchPlus.Contact-Point@iaea.org.

Selected participants will be informed in due course on the procedures to be followed with regard to administrative and financial matters.

Participants are hereby informed that the personal data they submit will be processed in line with the Agency’s Personal Data and Privacy Policy and is collected solely for the purpose(s) of reviewing and assessing the application and to complete logistical arrangements where required. The IAEA may also use the contact details of Applicants to inform them of the IAEA’s scientific and technical publications, or the latest employment opportunities and current open vacancies at the IAEA. These secondary purposes are consistent with the IAEA’s mandate.

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Additional Requirements

Participants should have a university degree in marine chemistry, biology, oceanography or a related scientific field, and should be currently involved in or planning to study the ecological impact of multiple stressors, including ocean acidification. Experience with the R software is strongly encouraged.

Selection will be based on merit and interest. Applications should include:

 * A motivation letter with a short description of the candidate’s research interests and how the course would benefit the applicant’s current or future research on ocean acidification and multiple stressors (max one A4 page)

  * CV with publication list

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Climate-driven reproductive dysfunction in cultured fish and shellfish: endocrine mechanisms, consequences and adaptive strategies

Published 4 November 2026 Science Leave a Comment
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Climate change is altering the environmental conditions experienced by aquatic organisms through rising temperatures, marine heatwaves, hypoxia, salinity fluctuations, ocean acidification and more frequent extreme events. Although the effects of climate change on growth, survival and disease have received considerable attention, reproductive impairment may occur before substantial mortality and can directly threaten aquaculture seed production. Reproduction depends on the coordinated interaction of environmental cues, neuroendocrine pathways, gonadal function, gametogenesis and energy allocation, making it particularly sensitive to environmental instability. In fish, climate-related changes can affect the brain–pituitary–gonad axis, steroidogenesis, sex differentiation, gametogenesis, gamete quality and spawning. Temperature is especially important because it influences endocrine regulation throughout reproductive development, while hypoxia, salinity changes and ocean acidification can further modify endocrine, metabolic and cellular processes. In shellfish, environmental stress can affect gonadal development, gametogenesis, spawning, fertilisation and larval performance through mechanisms that differ from those operating in vertebrate fishes. Multiple climate-related stressors may also act simultaneously, producing additive, synergistic or antagonistic effects. Parental exposure can further influence offspring through maternal provisioning, paternal effects and epigenetic mechanisms. These processes have direct implications for broodstock conditioning, hatchery seed production and the sustainability of aquaculture. This review examines the links between climate-related environmental change, reproductive endocrine regulation and reproductive performance in cultured fish and shellfish, with emphasis on gamete quality, spawning, early development, multiple-stressor interactions and reproductive resilience. Environmental management, broodstock selection, nutrition, acclimation, selective breeding, biomarker-based monitoring and climate-resilient hatchery technologies are considered potential approaches for sustaining reproductive performance under future environmental conditions.

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Oxidative stress as a potential mechanistic link between climate change and aquatic biodiversity loss

Published 4 November 2026 Science Leave a Comment
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Climate change is rapidly altering aquatic ecosystems through rising temperatures, ocean acidification, hypoxia, ultraviolet radiation, salinity fluctuations, and interacting environmental stressors. These changes impose substantial physiological challenges on aquatic organisms, with oxidative stress representing an important mechanistic pathway linking environmental disturbances to biological responses across multiple levels of organization. This review synthesizes current evidence on oxidative stress responses associated with climate change-related environmental stressors across aquatic taxa, including fish, aquatic invertebrates, corals, phytoplankton, macroalgae, amphibians, and polar and deep-sea organisms. We examine the mechanisms underlying reactive oxygen species production, disruption of antioxidant defenses, and oxidative damage, while critically evaluating biochemical, molecular, and omics-based biomarkers for environmental stress assessment. Particular emphasis is placed on how oxidative stress may translate from cellular and organismal responses into changes in growth, reproduction, behavior, survival, species distributions, population dynamics, community structure, biodiversity, and ecosystem resilience. We also highlight limitations of current biomarker approaches, including species-specific variability, methodological inconsistencies, and difficulties in extrapolating laboratory findings to natural ecosystems. Future research should prioritize integrated multi-biomarker and multi-stressor approaches, long-term ecological monitoring, standardized protocols, and the integration of omics, environmental DNA, remote sensing, and artificial intelligence. Overall, oxidative stress biomarkers provide complementary tools for assessing climate-change impacts on aquatic biodiversity and ecosystem resilience.

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Kinetics of dissolved inorganic carbon acquisition by red seaweeds (Rhodophyta) with and without carbon-dioxide concentrating mechanisms

Published 4 November 2026 Science Leave a Comment
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Seaweed responses to ocean acidification (OA) may depend on whether they possess a carbon dioxide (CO2) concentrating mechanism (CCM). Using photosynthesis versus dissolved inorganic carbon (DIC) experiments, we determined the photosynthetic affinity (K0.5(CO2)) for CO2 for the red algae Pollexfenia lobata (CCM), and Callophyllis rangiferina, Delisea pulchra and Plocamium cirrhosum (non-CCM). K0.5(CO2) was statistically similar for CCM and non-CCM species, but P. lobata had values lower than those published for isolated red algal Rubiscos. Maximum photosynthetic rates (Pmax) were 2.5 times higher for Pl. cirrhosum and D. pulchra. Non-CCM species may benefit from future OA because photosynthesis would be less limited by DIC.

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Silicate accumulation in taxonomically diverse seaweeds: morphology, uptake, visualization and environmental responses

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Silicon is required by some microalgae but use and accumulation by seaweeds has been quantified in few taxa. This study aimed to examine biogenic Si (bSi) in taxonomically and morphologically diverse seaweeds, measure Si uptake rates, assess the effects of environmental conditions on bSi, and visualize Si within seaweed tissues. bSi was determined in 57 seaweed taxa across 17 taxonomic orders collected around Tasmania, Australia. There were no clear phylogenetic trends in bSi, but fine filamentous morphologies showed higher bSi content than thicker thalli, suggesting structural roles of Si. Highly variable bSi could relate to epiphytes. Simulated ocean acidification and warming did not affect bSi in taxa with or without active CO2 uptake mechanisms. Across estuarine-marine gradients, bSi was higher in samples of the same taxa closer to riverine sources, possibly due to higher dissolved Si (dSi) availability. Selected seaweed taxa took up dSi, though slower than rates for macronutrients, and accumulation of bSi and internal dSi was stimulated by higher ambient dSi. Si was visualized in cell walls and marginal cells with Rhodamine 123 staining and epifluorescence microscopy. Si pools in seaweeds can be significant (>0.6 % DW) but more studies on Si growth dependence would be valuable.

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Climate-driven coral reef change and socio-ecological resilience: a bibliometric and systematic review

Published 4 November 2026 Science Leave a Comment
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Purpose

This study examines the evolution of research on climate-driven coral reef change and socio-ecological resilience through an integrated bibliometric and systematic review of peer-reviewed literature published between 2002 and 2025. The study addresses the fragmentation of existing research across ecological, socio-economic and governance perspectives by synthesizing evidence on climate stressors, ecosystem services, human well-being, adaptation strategies and resilience. It aims to map publication trends, identify dominant thematic structures and provide a comprehensive evidence base to support policy development and sustainable management of coral reef ecosystems and reef-dependent coastal communities.

Design/methodology/approach

The study employed a combined bibliometric and systematic review approach following the PRISMA 2020 framework. A total of 588 peer-reviewed publications published between 2002 and 2025 were retrieved from the Scopus database after a structured screening process. Bibliometric analysis was conducted using Bibliometrix (R) and VOSviewer to examine publication trends, citation patterns, collaboration networks and thematic structures. The systematic review synthesized evidence on ecosystem services, human well-being, adaptation strategies and governance mechanisms, enabling an integrated assessment of climate-driven coral reef change and socio-ecological resilience.

Findings

The findings reveal a rapidly expanding and increasingly interdisciplinary research field, characterized by strong growth in scientific output and extensive international collaboration. Six major thematic clusters were identified, centering on climate stressors, coral biology, ecosystem services, adaptation, governance and resilience. The review shows that fisheries, tourism, biodiversity conservation and coastal protection are the most frequently discussed ecosystem services linking reef health to human well-being. Key adaptation pathways include ecosystem-based management, marine-protected areas (MPAs), participatory governance, restoration initiatives and livelihood diversification, all of which contribute to strengthening socio-ecological resilience under climate change.

Research limitations/implications

This study is limited to publications indexed in the Scopus database and restricted to English-language literature, which may have excluded relevant studies from other databases and regional sources. The findings provide a comprehensive understanding of the intellectual development of coral reef socio-ecological resilience research and highlight the need for greater integration of ecological, economic and governance perspectives. Future research should strengthen links between ecological indicators and socio-economic outcomes, particularly in underrepresented regions, to support more context-specific adaptation strategies and evidence-based coral reef management.

Practical implications

The findings provide valuable guidance for policymakers, marine resource managers and conservation practitioners seeking to enhance coral reef resilience under climate change. The study highlights the importance of integrating ecosystem-based management, MPAs, participatory governance and livelihood diversification into coral reef management frameworks. By demonstrating the strong link between reef ecosystem health and human well-being, the study supports the development of adaptation policies that simultaneously protect biodiversity, sustain ecosystem services, strengthen coastal livelihoods and improve the resilience of reef-dependent communities facing increasing climate-related risks.

Social implications

The study underscores the critical role of coral reefs in supporting food security, employment, income generation and coastal protection for millions of people in tropical coastal communities. By highlighting the social consequences of climate-driven reef degradation, the findings emphasize the need for inclusive adaptation strategies that reduce vulnerability and strengthen community resilience. The study also reinforces the importance of participatory governance and livelihood diversification in enhancing social well-being, promoting equitable resource management and improving the capacity of reef-dependent populations to adapt to climate-related environmental change.

Originality/value

This study contributes to the literature by integrating bibliometric analysis and systematic review methods to provide a comprehensive synthesis of climate-driven coral reef change and socio-ecological resilience research. Unlike previous reviews that focus primarily on ecological or social dimensions, it bridges ecological disturbance, ecosystem services, human well-being and governance perspectives within a single analytical framework. By mapping the intellectual structure of the field and identifying key adaptation pathways, the study offers novel insights into the interconnected nature of reef resilience and provides a valuable evidence base for future research, policy, and management.

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The collapse of the marine ecosystems

Published 4 November 2026 Science Leave a Comment
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Over the last 265 million years the ocean has passed through five great crises in which a large pulse of carbon, or in one case an asteroid impact, changed the chemistry of seawater. This report compares those past events with the ocean of today, using two measures: the aragonite saturation of surface water and the share of marine life that was lost. The comparison shows that the modern ocean started from a weaker chemical position than in any of the past events, that its chemistry is now changing faster, and that its animal life has already fallen by between about one half and two thirds since 1850.

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Anthropogenic CO2-induced seawater acidification suppressed dimethylsulfide emissions in the northwestern Pacific marginal seas

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Marine dimethylsulfide (DMS) emissions exert a pivotal control on climate regulation via aerosol formation. Nevertheless, the biogeochemical cycle of DMS under seawater acidification remains poorly understood. Here we present integrated biogeochemical analyses that combine field observations, historical datasets, process-based modeling, and ship-based incubation experiments to elucidate pH-dependent regulatory mechanisms governing the cycling of DMS and its precursor dimethylsulfoniopropionate (DMSP) across the northwestern Pacific marginal seas. Our findings identify pH as the key driver of DMS spatial variability; moreover, DMS removal processes are highly sensitive to pH. Structural equation modeling reveals pH-driven cascading impacts on DMS mediated by dinoflagellate biomass. Incubation experiments further demonstrate that decreasing pH reduces high DMSP-producer abundance and suppresses both DMS biological production and removal rates, collectively inhibiting net DMS accumulation. These findings indicate that seawater acidification under the high-emission SSP5-8.5 scenario will reduce global marginal seas DMS emissions by 35%–66% by 2100, which may intensity regional and global warming. Our research provides new insights into the feedback mechanisms linking marine sulfur biogeochemical cycles and global climate change.

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Active calcifying fluid pH upregulation facilitates resilience of the coral Tubastraea aurea to ocean acidification

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Ocean acidification poses a critical threat to marine calcifiers, yet the physiological mechanisms allowing certain species to thrive in high-CO₂ environments remain poorly understood. Kueishan Island (Taiwan) provides a unique natural laboratory to address this gap. While nearby non-vent reefs support diverse coral communities, the strongly acidified hydrothermal vent fields at Kueishan Island are dominated by the azooxanthellate coral Tubastraea aurea. Here, we tested whether this persistence is driven by regulation of the calcifying microenvironment. Using skeletal boron isotope (δ¹¹B) composition and scanning electron microscopy (SEM), we reconstructed calcifying-fluid pH (pHCF) and assessed skeletal microstructure in specimens from the vent site (HV, pH ~6.6) and a reference site (FU, pH ~8.0). Despite a ~1.4-unit difference in ambient seawater pH (pHSW), the estimated pHCF was indistinguishable between sites (HV 8.45 ± 0.02, FU 8.38 ± 0.01), resulting in a markedly larger ΔpH (pHCF − pHSW) at the vents. While SEM analysis revealed no gross dissolution at the resolution examined, vent colonies were smaller than reference counterparts, suggesting possible growth constraints under extreme conditions (exploratory given limited colony replication). These findings indicate that T. aurea maintains elevated pHCF in exceptionally low-pH seawater, highlighting a physiological capacity that could contribute to skeletal maintenance under future acidified oceans.

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Trace metals in the coral holobiont: roles and regulation in a changing ocean

Published 3 November 2026 Science Leave a Comment
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Trace metals are key regulators of coral reef functioning, acting as essential micronutrients or toxic stressors depending on concentration, speciation, and biological regulation. Corals and their associated holobionts require metals such as iron, zinc, copper, manganese, cobalt, molybdenum, and vanadium for photosynthesis, antioxidant defense, calcification, and nutrient cycling, while elevated levels of these elements, and non-essential metals including cadmium, lead, mercury, and nickel can induce oxidative stress, disrupt metabolism, disrupt coral-algal symbiosis, and contribute to bleaching and mortality. This review synthesizes current knowledge on trace metals in corals using evidence from laboratory experiments, field studies, skeletal geochemistry, and omics-based investigations. The biological roles and regulation of trace metals within the coral holobiont, their physiological and molecular impacts across life stages, and the influence of biogeochemical cycling and environmental drivers on metal availability and exposure in reef systems are examined. Analytical and omics-based approaches for investigating coral and metal interactions are also evaluated. Altogether, current evidence indicates that coral responses to trace metals depend on external metal concentrations, physiological regulation and environmental context. As climate change and anthropogenic activities continue to modify ocean chemistry, redox conditions, and metal bioavailability, understanding these interactions will become increasingly important for anticipating coral responses to future environmental change. Substantial knowledge gaps remain regarding thresholds between essentiality and toxicity, interactions with climate stressors, and holobiont-level metal cycling. Addressing these gaps is essential for improving interpretation of coral metal records, predicting reef vulnerability, and informing effective conservation and management strategies in an increasingly anthropogenically altered ocean.

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Community metabolism generates chemical legacies that alter coral physiology

Published 3 November 2026 Science Leave a Comment
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Coral reefs are among the world’s most diverse ecosystems and contribute substantially to ocean productivity and the carbon budget. Disturbances are shifting reefs to altered community states, yet how these new communities indirectly alter organismal physiology by modifying the local biogeochemical environment remains largely unknown. We investigated this biogeochemical feedback in a 25-d mesocosm experiment in Mo’orea, French Polynesia. We exposed the common coral Porites rus to the biogeochemical environments generated by three distinct communities representative of recent benthic states in this system: coral-, macroalgae-, and crustose coralline algae-enriched relative to a seawater-only control. While net community production was similar among communities, net community calcification was lowest in the macroalgae-enriched state. Across treatments, community metabolism drove changes in the organic and inorganic carbon pool, with net community production increasing both pH and dissolved organic carbon. Using structural equation modeling, we tested how these community-generated chemical legacies propagated through coral physiology. Elevated pH increased chlorophyll a content, which increased endosymbiont density, tissue biomass, gross photosynthesis, and respiration through a series of indirect pathways. Dissolved organic carbon had no detectable effect on downstream corals at 25 d. These results reveal a mechanistic pathway linking disturbance-driven shifts in benthic communities to coral performance. Altered community metabolism modifies local carbon chemistry, which reshapes symbiont physiology and ultimately influences host metabolic function. By identifying the pathways through which community states engineer their chemical environment, this study provides a framework for predicting coral performance and ecosystem trajectories as reefs transition away from coral-enriched states.

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Assessment of sediment and water regimes in island ecosystems of the Gulf of Mannar: implications for ecological monitoring

Published 3 November 2026 Uncategorized Leave a Comment
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Island ecosystems are highly dynamic, and this study examined sediment and water regimes across four coral islands in the Gulf of Mannar to evaluate their ecological significance. Sediment and water samples were collected from four islands, with sediment analyses covering grain size, calcium carbonate (CaCO₃), organic carbon, organic matter, and key water parameters: pH, salinity, temperature, conductivity, dissolved oxygen (DO), turbidity, and total dissolved solids (TDS). Standardized protocols ensured consistency, and data analysis (ANOVA, correlation, regression, Principal Component Analysis (PCA)) was used to assess spatial variability and interrelationships. Sediment composition varied significantly (p< 0.05) in terms of sand, silt, clay, calcium carbonate, organic carbon, and organic matter, with regression analysis revealing a positive trend for silt and negative trends for the other components. PCA (KMO = 0.402; Bartlett’s p< 0.0001) revealed two principal components explaining 87.05% of total variance, with Component 1 linked to sand, organic carbon, and organic matter, and Component 2 to silt, clay, calcium carbonate, and organic matter. Water parameters also varied significantly (p< 0.05); conductivity (r = 0.369) and temperature (r = 0.302) correlated with island location, while temperature was strongly associated with conductivity (r = 0.478) and TDS (r = 0.405). PCA (Kaiser-Meyer-Olkin (KMO) = 0.563; Bartlett’s p< 0.0001) identified ionic strength and thermal regime as key environmental drivers. These findings establish critical baseline data, offering a robust framework that demonstrates how sedimentary composition and physicochemical parameters jointly regulate benthic-pelagic interactions and ecosystem resilience. Overall, island-specific sediment and water patterns exert strong control on ecological processes, providing early detection of environmental shifts and strengthening evidence-based adaptive management. The study offers valuable insights for ecological monitoring and conservation within the Gulf of Mannar region.

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Coupled increases in pelagic fish productivity and export productivity during the Paleocene-Eocene Thermal Maximum

Published 3 November 2026 Science Leave a Comment
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Ocean productivity is sensitive to climate change, and its decline in recent decades has profoundly impacted the biosphere. Yet its long-term trajectory under global warming remains a topic lacking consensus. To address this question, we use paired ichthyolith and marine barite accumulation rates to investigate marine productivity and associated biological responses during the Paleocene-Eocene Thermal Maximum. We find a widespread increase in pelagic fish productivity, particularly in the Pacific and North Atlantic, that closely tracks export productivity in trend and spatial pattern, suggesting this increase was fueled by enhanced carbon export from the surface ocean. Model simulations support the observed trend, demonstrating that under elevated pCO2 conditions, the effects of enhanced nutrient supply can outweigh the suppressive effects of ocean stratification on export productivity. Our findings highlight that the long-term response of marine productivity to sustained greenhouse warming may differ fundamentally from the short-term declines observed in the modern ocean.

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Time-variant bioeconomic risks on a gastropod fishery affected by uncertain ocean acidification trajectories

Published 3 November 2026 Science Leave a Comment
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Introduction: In the north-eastern Pacific, high-value abalone fisheries, which are sensitive to pH variations, require in situ pH data to properly assess the bioeconomic effects of their possible dynamic trajectories under alternative fishing mortalities.

Methods: In situ pH data were collected every 15 min using a HOBO® MX2501 sensor in the La Bocana pink abalone fishing grounds and compared them with Argo float and Copernicus Marine Service observations. The observed pH distribution was fitted to the Extreme Value Minimum distribution based on the Anderson–Darling goodness-of-fit statistic. Stochastic pH trajectories were generated through 10,000 Monte Carlo replications under three IPCC ocean acidification scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) and three fishing mortalities (FD = 0.02, 0.04, and 0.06). These trajectories were incorporated into a dynamic age-structured bioeconomic model by making individual growth and age-specific natural mortality functions dependent on pH. Biomass and resource rent per boat were projected from 2025 to 2100, and linear mixed-effects models, sensitivity analyses, and 95% confidence intervals were used to evaluate temporal responses and parameter uncertainty. Dynamic risks were estimated as the probability that biomass and resource rent fell below their respective limit reference points (LRPs: 190 t and USD 15,000 yr-1) across scenarios and fishing mortalities.

Results: The results indicate considerable variability in pH measurements between remote and in situ sources, which may introduce a proportional bias into the bioeconomic modeling if local observations are absent. Also, the effects of ocean acidification on H. corrugata biomass, survival, and fishery resource rent increase with time, IPCC pH scenario, and alternative exploitation intensity. Under the current exploitation rate (FMSY = 0.06), effects were negligible in the short term under SSP1-2.6, whereas by 2100 pH-related growth effects decreased by 4%, 13%, and 26% under SSP1-2.6, SSP2-4.5, and SSP5-8.5, respectively. Over the same period, pH effects on survival rates resulted in a slight increase of 2.14% under SSP1-2.6, but reductions of 6.48% and 22% under SSP2-4.5 and SSP5-8.5, respectively, while age-specific biomass peaks declined by up to 20% and 44% under SSP2-4.5 and SSP5-8.5. Mixed-effects models confirmed significant effects of pH scenario, exploitation rate, and time on biomass and resource rent, including significant interactions (all p < 0.001). By 2100, annual resource rent per small-scale boat was significantly higher under SSP1-2.6 than under SSP2-4.5 and SSP5-8.5 by USD 3,083 and USD 7,482, respectively (p < 0.0001). Under FMSY, the risk of biomass falling below its LRP was <25% during 2025–2040 but increased to 34% and 54% under SSP2-4.5 and SSP5-8.5, respectively, by 2100; corresponding risks for resource rent increased to 27% and 48%.

Discussion: These results indicate that ocean acidification may substantially increase the long-term bioeconomic vulnerability of the fishery, particularly under high-emission scenarios. Management actions to mitigate the undesired bioeconomic effects of OA will likely depend on the fishery authority’s risk attitude (i.e., degree of risk aversion) and corresponding exploitation-rate strategy selection.

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Unlocking spatial ecological assessment for tropical seagrass habitats using a new rapid assessment method (SEARAM)

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Highlights

  • Rapid and standardized assessment of tropical seagrass ecological state.
  • Multimetric index combining structure and vitality indicators.
  • Spatial mapping of seagrass fragmentation and degradation.
  • Links between habitat condition, environment, and megafauna.
  • A practical tool for coastal monitoring and impact mitigation.

Abstract

Seagrass meadows are key coastal ecosystems supporting biodiversity, carbon storage, and essential trophic functions, yet they are increasingly threatened by anthropogenic and climatic pressures. Based on the Seagrass Meadows Rapid Assessment Method (SEARAM), a standardized protocol grounded in seagrass biodiversity indicators (SBIs), we developed a reliable and operational index to assess seagrass ecological state at high spatial resolution. Using 536 circular plots and 144 faunal stations across three intertidal reef habitats in Mayotte (Western Indian Ocean), SEARAM integrates structural and vitality sub-indices into a composite seagrass ecological state index (SESI), spatialized by geostatistical interpolation and analyzed using ANOVA, PCA, and multiple regression models. Results revealed highly fragmented meadows dominated by Halodule uninervis and Halophila ovalis, with low canopy height (5 ± 2 cm) and substantial epiphyte loads (37 ± 17%). The inner fringing reef flat showed the poorest ecological state (SESI = 4.8 ± 0.7/10), whereas the barrier reef (5.4 ± 0.8/10) and exposed fringing reef flat (5.6 ± 0.8/10) exhibited moderate scores. Key environmental drivers (turbidity, grain size, pH), significantly explained spatial patterns of seagrass structure and vitality, confirming the influence of sediment and light regimes. Functional relationships were also demonstrated between seagrass condition and associated fauna, particularly green turtle density and dugong feeding traces. SEARAM proved to be a rapid and robust tool for diagnosing tropical seagrass states. Its multimetric framework connects benthic condition to habitat suitability for megafauna, offering an operational foundation for ecological monitoring, management, and impact mitigation within the Avoid–Reduce–Offset (ARO) doctrine.

Graphical abstract

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Climate-driven habitat loss of Chinese sturgeon in the Northwestern Pacific and implications for marine protected area design

Published 3 November 2026 Science Leave a Comment
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Highlights

  • Ensemble modeling integrates eleven algorithms to predict sturgeon habitat suitability.
  • Temperature is the dominant driver, followed by pH and total suspended matter.
  • Suitable habitats are projected to disappear completely by 2100 under SSP5–8.5.
  • Static protected areas must transition to climate-adaptive zoning strategies.

Abstract

The conservation of endangered anadromous fishes depends on understanding their full-lifecycle habitat requirements, yet the marine phase of Chinese sturgeon (Acipenser sinensis) remains a critical knowledge gap despite over 90% of its lifespan occurring at sea. We integrated multi-source occurrence data (satellite tagging, bycatch records, environmental DNA, and online databases) and applied an ensemble modeling framework (Biomod2 with eleven algorithms) to predict habitat suitability across the Northwestern Pacific Ocean (100°E–150°E, 10°N–55°N). After collinearity filtering, seven key environmental drivers were retained, among which mean temperature contributed most, followed by maximum pH, total suspended matter and mean silicate. The ensemble model achieved high predictive performance (median TSS = 0.944) and identified the Changjiang Estuary and coastal waters of Zhejiang and Jiangsu provinces as current distribution hotspots. Under the high-emission scenario (SSP5–8.5), suitable habitats are projected to disappear completely by 2100, accompanied by a significant northward contraction. These projections should be regarded as a potential worst-case scenario under high-emission conditions rather than a deterministic forecast. These findings demonstrate that business-as-usual emissions would eliminate viable marine habitat for this critically endangered species. Conservation priorities should therefore focus on (1) protecting benthic prey resources in the Changjiang Estuary and Zhoushan Archipelago as core refugia, and (2) transitioning from static marine protected areas to dynamic, climate-adaptive zoning informed by real-time habitat predictions. The ensemble modeling approach developed here is transferable to other data-limited, endangered marine species facing similar climate threats.

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Long-term stress induced by low bicarbonate alkalinity causes intestinal oxidative stress, gut microbiota imbalance and metabolic disorder in Scylla paramamosain

Published 3 November 2026 Science Leave a Comment
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Highlights

  • Low bicarbonate induces acid-base imbalance and oxidative stress
  • Opportunistic pathogen Klebsiella is a potential biomarker of the LB group.
  • Low bicarbonate affects chitin synthesis and gut barrier.
  • Low bicarbonate affects NDAA and gut microbiota.

Abstract

To investigate the effects of low bicarbonate alkalinity on intestinal health of Scylla paramamosain, we systematically evaluated the growth survival, intestinal antioxidant enzyme activities, and expression profiles of genes involved in immunity, inflammation, apoptosis and osmoregulation under low alkalinity conditions. Meanwhile, integrated intestinal microbiome and metabolome analyses were performed. The results showed that low bicarbonate alkalinity significantly reduced the survival and molting rates of S. paramamosain. It markedly elevated the activities of intestinal SOD, CAT and GSH-Px, as well as the expression levels of inflammation-related genes (IL-16, RELISH, LITAF), apoptosis-related genes (CASPASE7, BAX, BCL2) and osmoregulation-related genes (NKA, NHE, Cl−/HCO₃−), while suppressing the expression of immune genes (proPO, ALF1, LZM) (P<0.05). Low bicarbonate alkalinity disrupted the intestinal microbiota structure of S. paramamosain, accompanied by a decreased abundance of the phylum Bacteroidota and a significant increase in the abundance of the genus Klebsiella (P<0.05). A total of 714 differential metabolites were identified by metabolomic analysis, which were mainly annotated into Fatty Acyls, Glycerophospholipids, and Steroids and steroid derivatives. Multiple carbohydrate metabolism pathways were significantly enriched and participated in the regulation of Fructose 6-Phosphate (F6P). Integrated microbiome-metabolome analysis revealed that N,N-dimethyl arachidonoyl amine (NDAA) may cooperate with intestinal microorganisms to regulate the stress tolerance of S. paramamosain under low bicarbonate alkalinity stress. Based on the physiological and biochemical characterization of the intestine, this study elucidated the adaptive characteristics of S. paramamosain under low bicarbonate alkalinity. The findings provide important theoretical basis and practical significance for the saline-alkaline aquaculture of S. paramamosain.

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Spat origin does not affect phenotypic plasticity in the farmed mussel Mytilus chilensis facing experimental acidification

Published 2 November 2026 Science Leave a Comment
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Phenotypic plasticity allows organisms to cope with environmental variability, yet its role in sustaining aquaculture systems in the face of global change stressors remains poorly understood. We conducted a 90-day mesocosm experiment to test whether spat origin influences morphological, physiological, and periostracum responses in the Chilean mussel Mytilus chilensis under sustained experimental acidified conditions. Juveniles were collected from two contrasting habitats: an estuarine and dynamic/fluctuating environment, strongly influenced by freshwater discharges, and a marine, more stable environment; and then exposed to two pH regimes (8.0 and 7.5). Morphological traits showed subtle origin effects: estuarine mussels tended to exhibit higher shell length and calcification rates, though origin × pH interactions were not significant. Physiological responses were largely similar between both seed sources, with metabolic rates remaining stable while the clearance rate increased under acidified conditions in both populations. Periostracum analyses revealed some non-significant variation in organic composition, but no consistent effects of the pH were detected. Together, these results suggest that M. chilensis relies on conservative metabolic maintenance combined with flexible clearance responses possibly to cope with natural acidification pulses, while also tolerating sustained low-pH conditions, with only weak signals of origin-driven divergence. Our findings highlight the importance of phenotypic adjustments over local origin, suggesting that spat provenance may not be a primary determinant of performance under projected acidification scenarios tested here.

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The Arabian Seas: a window into future oceans —physical, biogeochemical, and ecological dynamics in unique marginal environments

Published 2 November 2026 Science Leave a Comment
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The Arabian Sea provide a sentinel system for understanding how global planetary boundary transgressions manifest through regional ocean processes. Their rapid warming, altered circulation, declining ventilation, deoxygenation, acidification, and ecological reorganization reveal interconnected regional manifestations of pressures associated with the Climate Change, Biogeochemical Flows, Ocean Acidification, and Biosphere Integrity boundaries. Regional physical and biogeochemical amplification compresses the timescale over which these pressures become ecologically consequential, exposing regional responses and increasing risks of regime shifts. Although the Arabian Seas possess distinctive environmental characteristics, the mechanisms linking planetary forcing to regional change are broadly relevant to other tropical and marginal oceans. Their present trajectory therefore provides a conditional, mechanism-based analogue for selected processes expected to intensify across future tropical open-ocean and marginal-sea environments. This illustrates how multiple global boundary transgressions may interact to weaken regional resilience and reorganize marine ecosystem function.

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Critical swimming speed in fish: measurement, determinants, and applications in aquaculture and fisheries management

Published 2 November 2026 Science Leave a Comment
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Critical swimming speed (Ucrit) is widely used as a non-invasive and practical metric for quantifying swimming performance in fish. This review summarizes current advances in Ucrit research, focusing on measurement methods, environmental and biological determinants, and the underlying genetic and molecular mechanisms. We highlight key methodological developments, including step and ramp protocols, while addressing ongoing challenges such as the lack of standardized procedures and the limited comparability across studies. Environmental factors, including temperature, dissolved oxygen, salinity, and ocean acidification, strongly influence Ucrit, while intrinsic traits such as body size, sex, and physiological capacity further shape its variation. Recent studies have begun to uncover the genetic architecture of Ucrit, with evidence from heritability estimates, genome-wide association studies, and transcriptomic analyses pointing to a polygenic basis and a central role of energy metabolism and mitochondrial function. We further discuss the applications of Ucrit in aquaculture and fisheries management, including selective breeding, exercise training, fish passage design, and stock enhancement. Finally, we outline future research directions, emphasizing the need to establish standardized measurement frameworks, develop high-throughput phenotyping technologies integrated with artificial intelligence, and achieve multi-omics integration. Advancing these approaches will deepen our understanding of swimming performance and facilitate the development of more efficient and sustainable aquaculture, while promoting continued innovation in fisheries science.

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Green total factor productivity and ocean health: a global panel analysis of institutional, environmental and economic drivers

Published 2 November 2026 Science Leave a Comment
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The deterioration of ocean health has become a critical global challenge due to increasing pressures from economic activities, environmental degradation, and institutional weaknesses. This study examines the impacts of economic growth, capture fisheries production, greenhouse gas emissions, and government effectiveness on ocean health at the global level during the period 2012–2022, using the Ocean Health Index (OHI) as a multidimensional measure of marine sustainability. A quantitative research design based on panel data analysis is employed using secondary data collected from the Ocean Health Index database, the World Bank, and Our World in Data. Descriptive statistics, correlation analysis, panel unit root tests, multicollinearity diagnostics, and panel model specification tests are conducted, followed by fixed-effects estimation with country-clustered standard errors. An environmentally extended Solow-residual method is then employed to calculate the Green Total Factor Productivity (GTFP) growth and added to an extended model of ocean health. The results indicate that there is a positive and significant relationship between economic growth and ocean health, and a negative and significant relationship between government effectiveness and ocean health. Ocean health is statistically significant and negatively associated with the growth of GTFP, while both capture fisheries production and GHGs are statistically insignificant. The study demonstrates that ocean health is a multidimensional socio-ecological phenomenon shaped by the interaction of economic, environmental, institutional factors and productivity related aspects. These findings contribute to the literature by integrating economic, environmental, institutional and productivity related dimensions to provide a broader understanding of the factors associated with ocean health across countries.

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