Continental-shelf marginal seas play a pivotal role in the global carbon cycle. The coastal South Yellow Sea (SYS), located in an intense land–ocean interaction zone, is a key region for coastal carbon cycle research. The issue addressed in this region is that strong land–sea interactions have resulted in pronounced spatiotemporal heterogeneity of marine carbon sources and sinks, leading to high uncertainty in regional carbon flux estimation and an incomplete understanding of the underlying driving mechanisms. Therefore, the objective of this study was to systematically analyze the spatial variations, interannual trends, and key influencing factors of carbon sources and sinks in the coastal SYS. Methodologically, the following approach was taken: We combined shipboard in situ monitoring with multi-source environmental datasets, and developed a LightGBM machine learning model to map surface seawater partial pressure of carbon dioxide (pCO2) and air–sea CO2 fluxes at a spatial resolution of 1 km. The results indicated that surface seawater pCO2 in the coastal SYS exhibited a clear spatial gradient of “high in the south and low in the north, and higher in nearshore waters than in offshore waters”. The average pCO2 across the study region during summer was 409.9 μatm. On an annual scale, the Nantong coastal area had the highest pCO2 level, while the Lianyungang coastal area maintained a relatively low and stable pCO2 level. The air–sea CO2 flux followed a typical seasonal pattern of “winter carbon sink, summer carbon source”: the Lianyungang sea area acted as a weak carbon sink throughout the year, whereas the Nantong sea area functioned as a carbon source in summer. Over the past 20 years, pCO2 levels in the coastal waters have shown a gradual increasing trend. Nutrients and primary productivity were the core factors regulating regional carbon fluxes, with correlation coefficients of 0.58 and 0.64 between carbon flux and nutrients and chlorophyll-a in the Nantong sea area, respectively. The evidence allows us to conclude that eutrophication induced by terrestrial nutrient inputs, combined with organic matter decomposition, is the dominant driver of carbon release in the southern coastal waters. This study provides valuable technical support for coastal pollution management, carbon sink enhancement, and ocean acidification response in the SYS and analogous marginal sea systems.
Continue reading ‘Spatiotemporal characteristics of carbon source–sink dynamics in the coastal waters of the south Yellow Sea, China’Spatiotemporal characteristics of carbon source–sink dynamics in the coastal waters of the south Yellow Sea, China
Published 13 November 2026 Science Leave a CommentTags: biogeochemistry, chemistry, field, modeling, North Pacific, regionalmodeling
Epigenetic intelligence: how organisms track their environment through molecular memory
Published 13 November 2026 Science Leave a CommentTags: adaptation, biological response, corals, individualmodeling, methods, modeling, molecular biology, mollusks, morphology, otherprocess, physiology, reproduction, review, zooplankton
The regulation of gene expression by epigenetic markers is a growing area of focus for researchers who seek to explain rapid phenotypic acclimatization to environmental change. Yet even as empirical datasets accumulate exponentially, the mechanistic underpinnings of epigenetic changes and their role in connecting environmental variation with the regulation of gene function remain unclear. Here, we use a stochastic model of epigenetic change to generate three testable predictions: (1) that organisms require environmental feedback to track their environments through epigenetic responses, (2) that this tracking requires coordination between the addition and removal of epigenetic markers, and (3) that epigenetically driven tracking is only effective under specific subsets of environmental variability. Despite the intuitiveness of these postulates, few to no experimental studies directly test them. Using marine invertebrates as a case study, we review correlational evidence consistent with the model’s predictions, describe hypothetical mechanisms by which epigenetic strategies could evolve, and clearly identify knowledge gaps and urgent experimental needs in the field. Overall, the field of environmental epigenetics is poised for major advances, which can be enhanced through the continued synthesis of mathematical frameworks and empirical data.
Continue reading ‘Epigenetic intelligence: how organisms track their environment through molecular memory’Using global climate models to inform multi-driver biological ocean experiments
Published 13 November 2026 Science Leave a CommentTags: chemistry, globalmodeling, methods, modeling, multiple factors, phytoplankton, temperature
This century, widespread shifts in temperature and CO2-driven acidification are projected for the surface ocean. Determining how ocean biota will respond to these changes requires scaling multiple drivers together because biological responses to one driver often depend on the conditions of the others. However, ocean temperature and carbonate chemistry vary across regions, seasons, and emissions scenarios, creating more combinations than laboratory experiments can test. While best-practice literature recommends designing experiments around climate projections, translating complex model output into a tractable set of realistic multi-driver treatments requires simplifying substantial spatial, seasonal, and scenario-dependent variation. To address this, we synthesized surface-ocean model projections into relevant multi-driver scalings of temperature and the full carbonate system across three decades (1850s, 2000s, and 2090s). These scalings use public data from the Coupled Model Intercomparison Project Phase 6 (CMIP6) which we group into 14 open-ocean biomes with annual and monthly mean conditions. The biome means reveal that most projected temperature changes are smaller than spatial and seasonal variation, whereas possible future carbonate system changes exceed present day variability. We then compared these projections with 2,456 treatments reported in 196 phytoplankton studies spanning the last two decades. We find that the majority of treatments (57%) fall within the modeled condition space, but many studies examine conditions unrealistic for the past or future open ocean. Finally, we applied North Atlantic conditions in batch cultures of two eukaryotic phytoplankton taxa. The achieved carbonate-system conditions fell within modeled biome variability, and the temperature increase matched projected warming. Together, this framework provides regional and emissions-scenario context for selecting tractable multi-driver treatments and comparing conditions across experiments.
Continue reading ‘Using global climate models to inform multi-driver biological ocean experiments’Uncoupling the effects of pH and pCO2: how Phaeocystis globosa adapts its nitrogen assimilation to an acidifying ocean
Published 13 November 2026 Science Leave a CommentTags: adaptation, algae, biological response, growth, molecular biology, otherprocess, photosynthesis, physiology, phytoplankton
Ocean acidification (OA) fundamentally reshapes the chemical landscape of coastal waters, yet the mechanistic basis for the resilience and metabolic adaptation of the bloom-forming alga Phaeocystis globosa remains poorly understood. By disentangling the individual and interactive effects of elevated pCO2 and reduced pH, this study shows that P. globosa exhibits distinct physiological and metabolic responses to these stressors. Reduced pH emerged as the stronger physiological constraint, significantly inhibiting growth, whereas the reduction in relative maximum electron transport rate (rETRmax) was not statistically significant; these responses override the potential benefits of CO2 fertilization. Transcriptomic profiling revealed diver-specific reprogramming of carbon and nitrogen metabolism: reduced pH induced coordinated down-regulation, elevated pCO2 coordinated up-regulation, and combined stress opposing trends. Key nitrogen genes (NR, NiR, GS) shifted phase-dependently. The absence of detectable CPS and OTC transcripts, together with multiple pathways potentially contributing to endogenous ammonium supply, points to a potentially truncated urea cycle and flexible nitrogen utilization. As an exploratory transcriptomic analysis, these results suggest that P. globosa may possess ecological resilience under future acidification.
Continue reading ‘Uncoupling the effects of pH and pCO2: how Phaeocystis globosa adapts its nitrogen assimilation to an acidifying ocean’Surfgrass canopy cover drives non-linear changes in tidepool biodiversity and seawater chemistry
Published 13 November 2026 Science Leave a CommentTags: abundance, biological response, BRcommunity, chemistry, field, mesocosms, otherprocess, phanerogams
Ocean acidification (OA) and deoxygenation, driven by anthropogenic CO2 emissions, threaten marine biodiversity by altering seawater chemistry and disrupting ecosystems. Foundation species like marine macrophytes may locally mitigate these stressors through metabolic activity, potentially improving the average condition or providing daytime refugia and influencing community structure. Yet few studies have quantified the influence of plant structural traits, like canopy cover on the buffering potential of marine macrophytes. We investigated how the canopy cover of surfgrass Phyllospadix spp., dominant macrophytes in northern California tidepools, relates to local seawater chemistry (pH and dissolved oxygen) and biodiversity. Through instantaneous sampling of 29 tidepools and continuous sampling in focal pools, we found non-linear relationships between surfgrass cover, pH, dissolved oxygen, and community diversity. Pools with intermediate surfgrass cover (~40%) had maximum overall species diversity and macrophyte diversity, and largest diel fluctuations in pH and dissolved oxygen, while the highest surfgrass abundances were associated with decreased diversity and dampened chemical variation. A controlled mesocosm experiment corroborated the field pattern: surfgrass in mesocosms caused chemical fluctuations comparable to those in natural tidepools with similar surfgrass abundance. These results suggest that surfgrass can influence ecosystem function through direct metabolic effects and can facilitate or inhibit community diversity depending on its abundance. Our findings underscore the complexity of foundation species’ roles in coastal ecosystems and highlight the need to account for non-linear responses when predicting refugia potential of marine macrophytes.
Continue reading ‘Surfgrass canopy cover drives non-linear changes in tidepool biodiversity and seawater chemistry’An experimental approach to assessing climate sensitivity in juvenile Yellowbelly Flounder (Rhombosolea leporina): methodological insights and applications
Published 13 November 2026 Science Leave a CommentTags: biological response, fish, laboratory, mortality, multiple factors, performance, physiology, reproduction, South Pacific, temperature
As anthropogenic CO₂ emissions continue to rise, marine ecosystems face the dual threats of ocean acidification and ocean warming. A number of studies have examined the effects of ocean acidification and warming on coastal marine fin fish species, but little attention has been paid to estuarine species, the assumption being that they are likely to be tolerant to fluctuations in seawater parameters given freshwater and large tidal dynamics. This thesis investigates the impacts of these stressors on the early life history of the estuarine yellowbelly flounder (Rhombosolea leporina), an ecologically and culturally significant taonga species in New Zealand.
Research was conducted in two phases; a larval pilot study focusing on the transition to exogenous feeding, and a behavioural study on juveniles assessing olfactory mediated responses to food and predator cues.
The larval pilot study, carried out in aquaria, revealed an extreme developmental bottleneck at approximately 14 days post-hatch (dph). Mass mortality occurred across all treatments, coinciding with the onset of metamorphosis and the “critical period” of first feeding. The extent of the mortality event masked any possible treatment effects imposed in terms of pH and temperature combinations. These results highlight the high physiological sensitivity of R. leporina during early ontogeny, independent of climate stressors.
In the second phase, juvenile flounder were exposed to a fully-crossed factorial design of pH (~7.3 & ~8.0) and temperature (20°C & 25°C). Behavioural trials using a two channel choice chamber measured the proportion of time spent in stimulus streams (Perna canaliculus food cues & Notolabrus celidotus predator cues). A three-way ANOVA revealed a significant main effect of stimulus type (p = 0.017) and temperature (p=0.040), but no significant effect of pH and no interactive effects. Interestingly, 66.7% of individuals remained in the neutral mixing zone, particularly during predator trials and under elevated temperatures.
These findings suggest that while R. leporina larvae remain highly vulnerable to intrinsic developmental bottlenecks, juveniles exhibit a degree of behavioural resilience to reduced pH, potentially due to their evolved tolerance of fluctuating estuarine environments. The preference for remaining stationary (crypsis) in the neutral zone is interpreted as a natural, risk-averse strategy for this benthic species. This research underscores the importance of considering species-specific ecology and life stage transitions when predicting the impacts of climate change on New Zealand fisheries.
Overall, this research apparently represents the first study to experimentally examine the effects of ocean acidification and warming on estuarine flatfish species across critical early life stages. Although no clear pH-driven effects were detected in the juvenile behavioural trials, the study remains valuable in testing hypotheses around the resilience of marine species that naturally experience highly variable environmental conditions. In particular, species with significant estuarine habitat phases may possess inherent tolerance to fluctuations in seawater chemistry, yet may still face vulnerability during key developmental transitions. Investigations such as this are therefore important for improving our understanding of how climate change stressors interact with species-specific ecology and life history bottlenecks, and for informing future research on the adaptive capacity of estuarine-associated marine fishes.
Continue reading ‘An experimental approach to assessing climate sensitivity in juvenile Yellowbelly Flounder (Rhombosolea leporina): methodological insights and applications’Integrating knowledge for sustainable mangroves in Portuguese-Speaking African Countries (PALOP) through the nature’s contributions to people framework
Published 13 November 2026 Science Leave a CommentTags: Indian, mitigation, policy, review, socio-economy, South Atlantic
Mangrove ecosystems provide vital socio-ecological services, yet severe epistemic asymmetries leave coastal governance structurally understudied across Portuguese-Speaking African Countries (PALOP). Following PRISMA guidelines, this systematic review analyzes 132 peer-reviewed Web of Science publications (1991–2024) across Angola, Equatorial Guinea, Guinea-Bissau, Mozambique, and São Tomé and Príncipe. Using the 18 categories of the IPBES Nature’s Contributions to People (NCP) framework as a diagnostic lens, we map geographical disparities, thematic gaps, and socio-ecological representation across the region. Results reveal stark spatial inequalities, with Mozambique (62.1%) and Guinea-Bissau (25.7%) concentrating nearly 88% of regional scientific output, leaving the remaining three nations in severe empirical deficits. Across documented contributions, a reductionist “carbon-centric” bias dominates biophysical regulating functions account for over 60% of all recorded entries, whereas material dependencies (under 12%) and non-material values remain severely marginalized. Critically, we identify absolute knowledge vacuums in indirect regulating processes, namely pollination (NCP2), ocean acidification regulation (NCP5), and freshwater control (NCP6). These epistemic gaps decouple coastal management from local community dependencies, risking top-down “green-grabbing” under global climate agendas. Decolonizing research priorities, fostering regional cooperation, and integrating traditional ecological knowledge into co-designed management are essential to build sovereign evidence bases, protect community livelihoods, and equitably inform international climate and biodiversity targets.
Continue reading ‘Integrating knowledge for sustainable mangroves in Portuguese-Speaking African Countries (PALOP) through the nature’s contributions to people framework’Pteropod preservation reveals carbonate dissolution across the Mid-Pleistocene Transition and an Eemian preservation spike in the Andaman Sea
Published 13 November 2026 Science Leave a CommentTags: abundance, chemistry, dissolution, mollusks, otherprocess, paleo, zooplankton
Highlights
- ∼1.2-Myr record reveals major changes in Andaman Sea pteropod preservation.
- Pteropods show enhanced preservation during several glacial intervals.
- Poor MIS 25–14 preservation preceded variable preservation during the MBDI (MIS 13–11).
- Highest pteropod abundances span Termination II–MIS 5e (∼137–116 ka).
- Pteropod preservation reflects large-scale carbonate-system changes modulated by regional hydrography.
Abstract
Pteropods are aragonitic holoplanktonic molluscs whose shells preserved in marine sediments provide a sensitive archive of past seawater carbonate saturation state, intermediate-water ventilation, and monsoon-driven oceanographic change. Here, we present a ∼1.2 Myr record of pteropod assemblages and preservation from sediment core NGHP-17 (1344 m water depth) in the Andaman Sea. Sixteen species were quantified across 180 samples, together with the Fragmentation Ratio (FR), Limacina Dissolution Index (LDX), epipelagic/mesopelagic (Epi/Meso) ratio, and selected planktonic and benthic foraminiferal abundances. Pteropod preservation is episodic, with pronounced preservation peaks during several glacial intervals. In contrast, generally poor and intermittent preservation during MIS 25–14 characterizes much of the Mid-Pleistocene Transition (MPT), although preservation windows occur during MIS 22, 18, and 16. This pre-MBDI decline was followed by the Mid-Brunhes Dissolution Interval (MBDI; MIS 13–11), within which a pronounced MIS 12 preservation peak demonstrates that unfavorable conditions were not continuous. An earlier preservation event occurs during MIS 26. The highest pteropod abundance is observed across MIS 6–5e, with a maximum at ∼125 ka and species maxima spanning ∼137–116 ka, indicating a transient Termination II/deglacial-to-early-interglacial preservation event. The significant inverse relationship between total pteropod abundance and FR supports a substantial preservation control on the record. Overall, the results indicate that pteropod preservation at NGHP-17 was strongly influenced by changes in bottom-water aragonite preservation conditions, within a broader framework of large-scale carbonate-system changes and regional hydrographic variability.
Continue reading ‘Pteropod preservation reveals carbonate dissolution across the Mid-Pleistocene Transition and an Eemian preservation spike in the Andaman Sea’A systematic map of environmental and socio-economic effects in commercial bivalve production
Published 13 November 2026 Science Leave a CommentTags: fisheries, policy, review, socio-economy
Commercial bivalve systems underpin coastal economies, food provision, and livelihoods, yet evidence on how environmental exposures translate into socio-economic vulnerability remains fragmented. This systematic map aimed to characterise the peer-reviewed evidence base on the socio-economic outcomes of environmental exposures in commercial bivalve systems. Following Collaboration for Environmental Evidence guidelines and ROSES reporting standards, searches were conducted in Web of Science Core Collection and Scopus, supported by citation chasing and organisational website searches. While initial screening sought out grey literature, only peer-reviewed articles met our empirical inclusion thresholds upon full-text review. Eligible studies were published in English from 2005 onwards and examined commercial bivalve systems, at least one environmental exposure, and at least one stakeholder-relevant socio-economic outcome. Included studies were coded for geography, bivalve type, system type, stakeholder group, exposure, outcome, and mitigation or adaptation response. Twenty-eight articles met the inclusion criteria. The evidence base was geographically concentrated, with the United States contributing the largest share of studies. Clams, mussels, and oysters were the most frequently represented bivalve groups. Temperature and ocean acidification were the dominant exposures, followed by storms, heatwaves, and pollution runoff. Revenue, cost, and yield or production were the most frequently reported socio-economic outcomes across stakeholder groups and exposure types, whereas labour, food security, health, and social outcomes were less commonly examined. Regulation, scenario planning, forecasting, and sustainable farming were the most frequently documented responses. Overall, the evidence base is strongest in documenting economic and production-related vulnerability to major climate stressors, but remains weaker on slower-onset exposures, broader wellbeing dimensions, underrepresented stakeholders, and diverse adaptation pathways.
Continue reading ‘A systematic map of environmental and socio-economic effects in commercial bivalve production’Morphometric and morphological response of Eprolithus floralis to Oceanic Anoxic Event 2 (Cenomanian/Turonian, Late Cretaceous)
Published 13 November 2026 Science Leave a CommentTags: abundance, biological response, dissolution, morphology, otherprocess, paleo, phytoplankton
Understanding the response of calcareous nannoplankton to past environmental perturbations is critical for assessing the impact of paleoenvironmental changes on marine calcifiers. Here, we analyze the size, morphotype distribution, and abundance of Eprolithus floralis across Oceanic Anoxic Event (OAE) 2 at Clot Chevalier (SE France), Novara di Sicilia (S Italy), and Tarfaya (Morocco), and compare them with Eastbourne (UK) to distinguish supra-regional from local environmental controls.
Mean total diameter differs by ∼1 μm between northern and southern sections and decreases from pre-OAE 2 to OAE 2, with minimum mean values generally reached around peak B of the carbon-isotope excursion. The magnitude of this decrease varies among sections, reflecting different regional baseline conditions. Rounded specimens are on average ∼0.58 μm smaller than spiky specimens, and their increased relative abundance during OAE 2 contributes to the observed size decrease. Specimens with lowest size (3.2–3.5 μm) are extremely rare, suggesting a possible minimum size for the species. The magnitude of the morphometric response differs among sections, with the largest size reductions during OAE 2 at Clot Chevalier (16%) and Tarfaya (10%) and most complete post-OAE 2 recovery recorded at the northern localities, which also display the largest pre-OAE 2 average size. Neither temperature nor nutrient availability explains the common morphometric evolution observed across the four localities. Instead, the temporal correspondence between volcanism, atmospheric CO2 increase and the onset, maximum size decrease and recovery, suggests that perturbations of the marine carbonate system exerted a control on coccolithophore calcification.
Continue reading ‘Morphometric and morphological response of Eprolithus floralis to Oceanic Anoxic Event 2 (Cenomanian/Turonian, Late Cretaceous)’The ocean acidification data gap
Published 13 November 2026 Science , Web sites and blogs Leave a Comment
In 2025, the Potsdam Institute for Climate Impact Research determined that the ocean acidification planetary boundary had been breached for the first time, degrading the ocean’s ability to stabilise the global climate and pushing humanity and marine life beyond the agreed safe zone.
The ocean absorbs at least a quarter of the carbon dioxide released into the atmosphere, driving chemical changes that visibly affect marine life and ocean chemistry. Yet despite decades of research, a fundamental question remains difficult to answer: how exactly is ocean acidification changing marine ecosystems?
The Global Ocean Acidification Observing Network (GOA-ON)’s Biology Working Group has worked for years to demonstrate the real-world biological impacts of ocean acidification. Alongside observations and experience from marine communities, abundant evidence from laboratory experiments shows how different organisms respond to acidification. Coral reefs have eroded, lost biodiversity and become overgrown with algae; acidification is known to make it more difficult and energetically demanding for calcifying organisms, such as corals and shellfish, to grow and maintain their normal structures. What’s missing, however, is substantial long-term, quantifiable data to connect those responses to what is happening to the chemistry of seawater across the entire ocean.
Continue reading ‘The ocean acidification data gap’Ocean acidification impairs embryonic development and disrupts ink sac gene expression in the pharaoh cuttlefish (Sepia pharaonis)
Published 12 November 2026 Science Leave a CommentTags: biological response, laboratory, molecular biology, mollusks, morphology, mortality, North Pacific, physiology, reproduction
Background: Ocean acidification (OA) represents a growing threat to marine biodiversity, particularly affecting the sensitive early life stages of invertebrates. While the physiological impacts of OA are widely recognized, its specific effects on organogenesis and the molecular regulation of defensive traits in cephalopods remain poorly understood. This study investigated the influence of acidified seawater on the embryonic development and ink sac formation in the Pharaoh cuttlefish (Sepia pharaonis).
Methods: Embryos were reared under four pH conditions (8.0, 7.7, 7.3, and 6.5). Embryonic growth, survival, hatching success, and ink sac morphogenesis were monitored throughout development. The expression of melanin synthesis–related genes, including tyr, per, and spNOS, was quantified using qRT-PCR.
Results: Ocean acidification impaired embryonic development in a pH-dependent manner. Severe acidification (pH 6.5) resulted in complete mortality and no surviving embryos by Day 9, while moderate acidification (pH 7.3) led to delayed development and failure to hatch by Day 11, compared to the hatching observed in the control group. Ink sac development was markedly inhibited under acidified conditions, resulting in reduced size and pigmentation. Consistent with these morphological abnormalities, the expression of melanin synthesis markers, including tyrosinase (tyr) and peroxidase (per), exhibited a biphasic response, with early transient induction followed by consistent downregulation across all acidified treatments, while, the expression of the regulatory gene Sepia pharaonis nitric oxide synthase (spNOS) was significantly suppressed under severe acidification.
Conclusions: These findings provide evidence that OA is associated with disrupted embryogenesis and impaired ink sac formation in S. pharaonis, accompanied by altered expression of melanin synthesis-related genes. The resulting reduction in defensive capacity may increase the vulnerability of hatchlings and potentially affect population recruitment under future ocean acidification scenarios.
Continue reading ‘Ocean acidification impairs embryonic development and disrupts ink sac gene expression in the pharaoh cuttlefish (Sepia pharaonis)’3DSeaVizKit: an interactive spatiotemporal visualization toolkit for ocean data
Published 12 November 2026 Science Leave a CommentTags: biogeochemistry, chemistry, methods, modeling, regionalmodeling
Highlights
- Web-based toolkit for interactive 3D visualization of ocean data.
- Efficient pipeline for multivariate and multiresolution ocean products.
- Unified framework for scalar, vector, Lagrangian, and uncertainty fields.
- Reveals circulation, coherent structures, transport pathways, and 3D dynamics.
- Demonstrated in coastal, regional, biogeochemical, and uncertainty applications.
Abstract
Scientific understanding, prediction, and communication to stakeholders are common objectives of ocean simulations and observing campaigns. Achieving these objectives can be greatly facilitated by advanced tools for exploring dynamic three-dimensional ocean data. Many scientific visualizations of spatiotemporal simulations rely on static two-dimensional representations that omit one or more spatial dimensions, potentially obscuring important features and relationships. A toolkit capable of creating coherent three-dimensional visualizations of ocean processes should move beyond isolated two-dimensional views and support the exploration of increasingly high-resolution simulations and large multidisciplinary observational data sets. In this work, we present 3DSeaVizKit, a visualization toolkit that processes multidisciplinary oceanographic data in a modular and computationally efficient manner to create portable, web-based, interactive 3D visualizations. Built upon the Plotly JavaScript library, the toolkit enables exploratory analysis of complex ocean fields directly within a web browser. We provide a software pipeline tailored to the computational demands of multivariate 3D ocean visualization and demonstrate its utility for revealing transport pathways, coherent structures, circulation features, biogeochemical-acidification interactions, subduction dynamics, and forecast uncertainties in high-resolution ocean simulations. The toolkit supports scalar fields such as temperature, salinity, and biogeochemical tracers; vector fields such as velocity and vorticity; and Lagrangian products including trajectories, flow maps, and coherent structures. Applications include the visualization of the Loop Current system and eddy interactions in the Gulf of Mexico, subduction processes and forecast uncertainties in the Alboran Sea, coupled biogeochemical and ocean-acidification dynamics in Massachusetts Bay, and transport pathways and coherent structures around Nantucket and Martha’s Vineyard.
Continue reading ‘3DSeaVizKit: an interactive spatiotemporal visualization toolkit for ocean data’Potential governing mechanisms of iodine radioisotopes behavior in marine and freshwater fish: transfer, accumulation, biotransformation, and uncertainties under climate change
Published 12 November 2026 Science Leave a CommentTags: biological response, fish, physiology, review
Highlights
- Waterborne iodine isotopes uptake shifts from the gills to the GIT in seawater.
- Exposure pathway and chemical form shape biodistribution and kinetics.
- Accumulation in the gills and liver is determined more by species-specific factors.
- Climate stressors nonlinearly alter iodine isotopes metabolism.
Abstract
The anthropogenic, long-lived radioisotope 129I is a growing long-term concern for aquatic ecosystems due to its predominantly chronic release from nuclear industry facilities, high environmental mobility, and strong biological affinity. Unlike well-studied radionuclides, the mechanisms governing the transfer, accumulation, and biotransformation of iodine radioisotopes in marine and freshwater biota remain insufficiently understood, particularly in fish, which represent a critical link in human exposure pathways. This knowledge gap limits the accuracy of radiological risk assessments and the development of effective mitigation strategies for a contaminant that persists on geological time scales. These uncertainties are further amplified under climate change, as rising temperatures, acidification, and increased co-occurring pollutant loads alter fish physiology and affect iodine metabolism. In aquatic systems, 129I occurs mainly as iodide and iodate, both biologically relevant and involved in enzymatically mediated pathways leading to the synthesis of iodine-containing compounds, including thyroid hormones. Despite the ecological and physiological importance of these processes, existing reviews largely address iodine in fish in a general or thyroid-centered context. This review synthesizes and critically evaluates current knowledge on the mechanisms of iodine radioisotope transfer, accumulation, and biotransformation in marine and freshwater fish, with particular emphasis on membrane transport systems, tissue-specific metabolism, and climate change effects.
Graphical Abstract
Physio–biochemical and transcriptomic responses of the marine green microalga Chlorella sp. to elevated pH and total alkalinity
Published 12 November 2026 Science Leave a CommentTags: algae, biogeochemistry, biological response, growth, laboratory, molecular biology, North Atlantic, photosynthesis, physiology, phytoplankton
The effects of elevated pH and total alkalinity (TA ≈ HCO3– + 2CO32–) on marine primary productivity–the cornerstone of marine food webs and trophic dynamics–remains poorly understood. In this study, we investigated the physiological, biochemical and transcriptomic responses of the green microalga Chlorella sp. to elevated pH (pH = 8.30, TA = 2353 μmol kg–1) and elevated TA under high pH conditions (pH = 8.30, TA = 3854 μmol kg–1). Elevated pH reduced the growth rate and cellular carbohydrate contents, and down–regulated transcripts encoding key enzymes involved in photosynthetic carbon fixation (including ribulose–1,5–bisphosphate carboxylase/oxygenase (Rubisco) and carbonic anhydrase), as well as ion transport components (V–type H+ ATPase and Na+ (K+, urea)–H+ transporter). Conversely, elevated TA significantly enhanced the growth rate and increased cellular particulate organic carbon and carbohydrate contents. Furthermore, elevated TA mitigated the inhibitory effect of high pH by up–regulating or stabilizing gene expressions involved in carbon fixation, fatty acid biosynthesis and degradation pathways, V–type H+ ATPase and H+ exporter. Overall, these findings demonstrate that elevated TA effectively relieves high–pH stress and stimulates photosynthetic carbon uptake in Chlorella sp., providing valuable scientific insights in phytoplankton–mediated carbon dioxide removal (CDR) strategies.
Seawater pH measurement: a critical metrological assessment of operational scales and the unified pH scale
Published 12 November 2026 Science Leave a CommentTags: chemistry, methods, review
Ocean acidification, driven by rising anthropogenic CO2, causes a measurable decrease in seawater pH with consequences for marine ecosystems. Accurate, traceable pH measurement is essential for ocean monitoring sensors. This critical review examines five pH scales: the IUPAC activity scale (pH), the free proton scale (pHF), the total proton scale (pHT), the seawater scale (pHSWS), and the unified scale (pHabs). For each scale, the analytical methods, metrological assumptions, traceability chain to the SI, and measurement uncertainties are analyzed. The review updates the foundational 2016 work with subsequent developments and focuses particularly on the application of pHabs to saline solutions. In its current differential-potentiometric realization, pHabs yields an expanded uncertainty U(pH) ≈ 0.2 in seawater. GOA-ON expresses its goals as standard uncertainties (k = 1): 0.003 (climate) and 0.02 (weather), equivalent to U ≤ 0.006 and U ≤ 0.04 for k = 2. The reported U(pH) ≈ 0.2 is therefore approximately 33 times the climate-quality target and approximately 5 times the weather-quality target, compared at the same coverage. The dominant contribution is the residual liquid-junction potential; the standard uncertainty of 6.3 mV (k = 1) reported in dilute solutions corresponds, at 25 °C, to u(pH) ≈ 0.1 and U(pH) ≈ 0.2 for k = 2, consistent with the reported U(pH) ≈ 0.2. However, this dilute-solution estimate is not a validated uncertainty for seawater and should not be extrapolated to seawater without experimental validation. Liquid-junction effects are therefore a priority for potentiometric sensors and for the current pHabs realization. Spectrophotometric pHT sensors avoid a liquid junction but have distinct uncertainty contributions related to indicator characterization, optical measurement, temperature, salinity, and sample perturbation.
Continue reading ‘Seawater pH measurement: a critical metrological assessment of operational scales and the unified pH scale’Tissue-specific expression responses of antioxidant, immune, and metabolic genes in juvenile yellowfin tuna (Thunnus albacares) under acute low-pH stress
Published 12 November 2026 Science Leave a CommentTags: biological response, fish, laboratory, molecular biology, North Pacific, physiology
Acute reductions in seawater pH may disrupt acid–base regulation and physiological homeostasis in marine fish, but tissue-specific molecular responses in juvenile yellowfin tuna remain poorly understood. Juveniles of yellowfin tuna were exposed for 48 h to four seawater pH levels (8.1, 7.6, 7.1, and 6.6), with three replicate tanks per treatment. The expression of selected antioxidant-, immune-, inflammatory-, and metabolism-related genes in the liver and gill was quantified using qRT-PCR. In the gill, most examined genes were upregulated under low-pH exposure, although the magnitude and pH dependence of the responses varied among genes. In the liver, antioxidant genes and most immune-related genes were downregulated, whereas tnf-α was upregulated at pH 7.1. Hepatic metabolic genes also exhibited treatment-dependent responses: mdh2 was significantly downregulated across all low-pH treatments, whereas pck2 was significantly upregulated only at pH 7.1 and 6.6. In contrast, dgat1b was significantly downregulated exclusively at pH 7.1 and 6.6. These contrasting expression patterns demonstrate marked tissue specificity in the acute low-pH response of juvenile yellowfin tuna, with broader transcriptional activation in the gill and selective suppression and metabolic adjustment in the liver. The findings provide an initial molecular basis for further evaluating the physiological consequences of acute and chronic low-pH exposure in this high-metabolic-rate pelagic species.
Continue reading ‘Tissue-specific expression responses of antioxidant, immune, and metabolic genes in juvenile yellowfin tuna (Thunnus albacares) under acute low-pH stress’Microhabitat-driven variation in predator–prey interactions between the crab Acanthocyclus hassleri and the mussel Perumytilus purpuratus
Published 12 November 2026 Science Leave a CommentTags: biological response, BRcommunity, crustaceans, field, mollusks, morphology, multiple factors, performance, predation, salinity, South Pacific, temperature
Highlights
- Microhabitat variability modulates predator–prey interactions in rocky intertidal systems.
- Tide pool mussels experience recurrent hyposalinity and low pH conditions.
- Reduced shell resistance increases predation vulnerability in tide pool mussels.
- Fine-scale coastal heterogeneity drives trait-mediated trophic interactions.
Abstract
This study evaluates how the microhabitat of origin of the mussel Perumytilus purpuratus is associated with its vulnerability to predation by the crab Acanthocyclus hassleri. A comparison was made of individuals of P. purpuratus from three intertidal microhabitats: higher limit, lower limit, and tide pool (HL, LL, TP, respectively). The latter receives freshwater inputs associated with an adjacent stream and rainfall. Three environmental variables (salinity, temperature, and pH) and prey shell-breaking strength were measured, and predation experiments using single-prey and mixed-prey diets were also conducted. These experiments evaluated attack rate, handling time, attack zone, size of prey consumed, and crushing claw force. The results indicate that TP experience more extreme conditions, with lower salinity and pH during low tide compared with the other microhabitats (HL and LL). These conditions were associated with lower shell-breaking strength, which may reduce prey resistance to predator attacks. While attack rate remained similar across different diets, under a mixed diet, the predator A. hassleri showed greater consumption of mussels from TP. Tide pool prey also tended to require less handling time than prey from the other microhabitats. The anterior region of the prey shell (umbo area) was the most frequently attacked, regardless of the microhabitat. Smaller individuals from LL were more frequently consumed, whereas larger prey sizes were targeted in HL and TP. A. hassleri possesses the strength necessary to attack prey from all three microhabitats. Overall, these findings suggest that microhabitat-associated differences in shell characteristics may influence prey vulnerability to predation and shape prey selection by A. hassleri.
Continue reading ‘Microhabitat-driven variation in predator–prey interactions between the crab Acanthocyclus hassleri and the mussel Perumytilus purpuratus’Cross-network synergies fundamental to sustained global ocean carbon observing
Published 12 November 2026 Science Leave a CommentTags: biogeochemistry, chemistry, methods, modeling, review
Abstract
The ocean’s critical role in absorbing anthropogenic carbon dioxide (CO2) and the resulting changes in the ocean carbon cycle are monitored by global-scale observing networks, including the Global Ocean Ship-based Investigations Program (GO-SHIP), Surface Ocean CO2 Observing Network (SOCONET), and Biogeochemical-Argo (BGC-Argo). Given the scale of the challenge to characterize the evolving ocean carbon cycle, no single network is sufficient; a coordinated, collaborative, cross-network approach is essential. This manuscript describes the overarching research questions driving these three networks and details their inherent synergies and dependencies, such as GO-SHIP and SOCONET delivering reference-quality measurements for validation of other in situ and satellite-based data, GO-SHIP providing opportunities for float deployment, and BGC-Argo filling gaps with high-frequency autonomous data. We provide recommendations for optimizing these relationships and an intra-network strategy moving forward. As representatives of the science committees for these networks, we are committed to sustaining and enhancing the collaborative structure necessary to fill critical knowledge gaps in ocean carbon cycle research, improve climate prediction, and enable future ocean ecosystem forecasting.
Plain Language Summary
The ocean plays a vital role in absorbing human-caused emissions of carbon dioxide, but this process is changing the ocean’s carbon cycle. Monitoring these vast global ocean changes requires a coordinated approach involving three major ocean observing networks: GO-SHIP, SOCONET, and BGC-Argo. This paper details how to maximize synergies across these networks to close critical knowledge gaps, improve climate prediction, and enable ocean ecosystem forecasts.
Continue reading ‘Cross-network synergies fundamental to sustained global ocean carbon observing’Red list of ecosystems assessment of Pacific coral reefs
Published 12 November 2026 Science Leave a CommentTags: biological response, calcification, community composition, corals, fisheries, mortality, North Pacific, policy, review, South Pacific
Coral reefs of the Pacific region extend across approximately 30°N to 30°S, covering roughly 35 500 km2. They range from tropical waters of Papua New Guinea in the West to subtropical latitudes, such as Southeastern Pitcairn or Northern Hawaii borders. This encompasses 21 coral reef ecoregions as defined by the Marine Ecoregions Of the World (MEOW) and Marine and Coastal Biodiversity Management in Pacific Island Countries (MACBIO) classifications. The region hosts exceptionally diverse coral and reef fish communities, the latter featuring high levels of endemism in various locations, and is characterised by extensive tropical archipelagos and atolls spanning wide gradients in ocean productivity, human influence, remoteness, geomorphology and climatic conditions. These ecosystems face increasing pressure from ocean warming and marine heatwaves, acidification, extreme weather events, invasive and harmful species outbreaks, overfishing, coastal development and pollution. The IUCN Red List of Ecosystems assessment, based on the benthic and fish datasets from the Global Coral Reef Monitoring Network (1993-2024) and the NOAA Degree Heating Weeks (DHW) dataset (1985-2025), found that coral reefs within all 21 Pacific ecoregions were at a high risk of collapse (i.e. featuring declining attributes to levels where the ecosystem transforms into a different type or is completely lost). This result was, however, largely driven by future climate change projections. Indeed, several criteria assessed in this work are still showing optimistic trends at the regional scale, especially when looking at the actual distribution of Pacific coral reefs or when comparing past and recent estimates of coral cover decline. Under Criterion A (decline in hard coral cover distribution), about 72% of the Pacific reef surface area (14 ecoregions) was classified as Least Concern, while 14% (3 ecoregions) was Vulnerable and 13% (4 ecoregions) was Endangered. Under Criterion B (restricted distribution), about 95% of the Pacific reef area (17 ecoregions) was Least Concern, while 3% (encompassing 3 ecoregions) was Vulnerable. Under Criterion C1 (observed thermal stress), the trend is reversed, with 49% of the reef area (9 ecoregions) classified as Vulnerable, 19% (6 ecoregions) as Endangered and the remaining 32% as either Near Threatened (5 ecoregions) or Least Concern (New Caledonia only). Criterion C2 (projected thermal stress) drives the entire Pacific reef area and all 21 ecoregions to Critically Endangered. Under Criterion D (alteration of biotic interactions), about 52% of the reef area (7 ecoregions) was either Least Concern or Near Threatened, 16% (7 ecoregions) was Vulnerable and 32% (7 ecoregions) was either Endangered or Critically Endangered. These results highlight the need to consolidate reef resilience towards future climate change and to reinforce the conservation of coral reef habitats through strengthened area-based management, sustainable fisheries operation, climate adaptation measures and accelerated global efforts to reduce greenhouse gas emissions.
Continue reading ‘Red list of ecosystems assessment of Pacific coral reefs’
