Understanding how marine species tolerate acidified conditions is critical for predicting biological responses to ocean change. A recent one-year experiment (Long 2026) found that juvenile snow crab (Chionoecetes opilio) maintain growth and molting under acidification (pH 7.8, 7.5), and survival begins to decline only after ∼250 days under severe acidification (pH 7.5). In this companion study, we characterized whole-transcriptome responses after 8 hours and 88 days of exposure to identify molecular mechanisms underlying short-term tolerance and chronic effects of ocean acidification. The immediate transcriptional response involved strong activation of genes associated with mitochondrial metabolism and biogenesis, protein homeostasis, cuticle maintenance, and immune modulation, processes shared between moderate and severe treatments but of greater magnitude under severe acidification. After 88 days, expression patterns diverged, revealing sustained upregulation of stress- and damage-mitigation pathways in the severe treatment (pH 7.5) compared to the moderate treatment (pH 7.8). These findings indicate that crabs in severe acidification are likely to experience chronic OA stress that precedes outward physiological effects, and provides a mechanistic basis for delayed mortality. We further highlight potential early indicators of chronic acidification stress in snow crab, among which a gene likely coding for carbonic anhydrase 7 (CA7, GWK47_031192) appears to be the most promising biomarker.
Continue reading ‘Short-term mechanisms, long-term consequences: molecular effects of ocean acidification on juvenile snow crab’Posts Tagged 'biological response'
Short-term mechanisms, long-term consequences: molecular effects of ocean acidification on juvenile snow crab
Published 20 February 2026 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, molecular biology, morphology, mortality, North Pacific, otherprocess, physiology, reproduction
Indo-Pacific coral reef sponge diversity declines under predicted future ocean conditions
Published 19 February 2026 Science ClosedTags: abundance, biological response, BRcommunity, community composition, corals, laboratory, mesocosms, multiple factors, North Pacific, otherprocess, porifera, temperature
Future oceans are predicted to favor groups like sponges over calcifying taxa such as scleractinian corals. Here, we test this hypothesis by examining the development of coral reef communities in experimental mesocosms over 23 months. 85 sponge species among the calcifying class Calcarea (~33%), and non-calcifying Demospongiae (~60%) and Homoscleromorpha (<10%) recruited to warming (+2°C), acidification (-0.2 pH), and warming+acidification (+2°C, -0.2 pH) future ocean treatments. The diversity of calcifying sponges was unimpacted across any treatment, whereas non-calcifying classes showed greatest declines. 57-66% of demosponges decreased under future ocean conditions, and homoscleromorphs were entirely absent from acidified treatments. Through the sponge loop, sponges play a fundamental role in coral reef nutrient cycling, and altered coral reef community composition likely has functional consequences. This study challenges the assumption that non-calcifying species are less impacted and highlights the importance of understanding how community composition may alter ecosystem functioning under future ocean conditions.
Continue reading ‘Indo-Pacific coral reef sponge diversity declines under predicted future ocean conditions’Molecular indicators of warming and other climate stressors in larval Pacific cod
Published 19 February 2026 Science ClosedTags: biological response, fish, molecular biology, morphology, multiple factors, North Pacific, reproduction, temperature
Recent marine heatwaves in the Gulf of Alaska negatively impacted Pacific cod (Gadus macrocephalus) through a series of failed year classes and poor recruitment to the fishery. Experimental work by Slesinger et al. (2024) corroborated the hypothesis that warming directly impacts recruitment by increasing larval mortality rates. In this companion study, we applied transcriptomics with larvae from Slesinger et al. (2024) to better understand how warming affected their physiology and identify potential mechanisms contributing to mortality. RNASeq data reveal that warm-exposed larvae have unique gene expression profiles that may reflect high levels of inflammation, lipid dysregulation or depletion, and altered development of visual systems and neurological pathways. Warming may therefore cause a metabolic mismatch whereby energy-demanding activities (development, inflammation, growth) exceed energy production capacity despite access to prey. We also report the less pronounced transcriptional differences in larvae exposed to cold, acidification, and a combination of stressors reflecting future climate scenarios. This information will guide future genetic and experimental work that will ultimately inform recruitment forecasts in years with conditions similar to those tested here.
Continue reading ‘Molecular indicators of warming and other climate stressors in larval Pacific cod’Experimental observations on ultrastructure of scales of red seabream (Pagrosomus major) for seawater pH monitoring
Published 18 February 2026 Science ClosedTags: biological response, dissolution, fish, laboratory, morphology, North Pacific
Ocean acidification monitoring relies predominantly on field test and numerical modeling, while bioindicators are emerging as practical and economic approaches for seawater pH monitoring. Here, we report indoor dissolution experiments on the scale of red seabream (Pagrosomus major) under varied pH (from 7.1 to 7.9), showing that the mean aspect ratio of ventral ctenii and caudal/ventral lepidonts negatively correlated with pH. We propose to employ these ultrastructures of fish scale to be a novel bioindicator for marine pH reconstruction. This semiquantitative proxy would be applicable to both contemporary biomonitoring and paleo-oceanic pH reconstruction for the extensive occurrences of fish in modern oceans and fossil records.
Continue reading ‘Experimental observations on ultrastructure of scales of red seabream (Pagrosomus major) for seawater pH monitoring’Population-level transcriptomic datasets from two benthic invertebrates exposed to long-term experimental warming and acidification
Published 18 February 2026 Science ClosedTags: biological response, laboratory, Mediterranean, molecular biology, mollusks, multiple factors, porifera, temperature
Ocean warming and acidification are major drivers of change in marine ecosystems, with particularly strong impacts on low-mobility benthic organisms. Despite their ecological importance, genomic and transcriptomic resources for sponges (Phylum: Porifera) and marine gastropods (Phylum Mollusca) that capture responses to long-term, combined climate stressors and population-level variability remain limited. Herein, we present population-level RNA-seq datasets from the sponge Chondrilla nucula and the gastropod Hexaplex trunculus, collected from northern and southern Aegean Sea (Eastern Mediterranean) populations and exposed for three months to elevated temperature and reduced pH in a common garden experiment simulating near-future climate change conditions. The datasets comprise high-quality paired-end Illumina reads, a complete de novo transcriptome assembly for C. nucula, and genome-guided alignments for H. trunculus. These datasets provide a valuable resource for investigating transcriptional plasticity and climate change resilience in benthic marine invertebrates.
Continue reading ‘Population-level transcriptomic datasets from two benthic invertebrates exposed to long-term experimental warming and acidification’The silent shift: how ocean acidification and rising temperature affect marine organisms
Published 17 February 2026 Science ClosedTags: biological response, review
The increased absorption of carbon dioxide from the atmosphere is the cause of ocean acidification. This has an adverse effect on marine calcifiers such as corals and shelled mollusks by lowering ocean pH and altering carbonate chemistry. Global warming-induced increases in ocean temperatures have serious repercussions for marine life as well, upsetting food webs, changing species ranges, and compromising physiological functions. The early life stages of shelled mollusks, such as gastropods and bivalves, are the most susceptible to the effects of ocean acidification. The growth, shell production, and survival of both juvenile and adult mollusks can be adversely affected by ocean acidification. The nutritional value of phytoplankton, the foundation of the marine food chain, may be impacted by ocean acidification. This may limit zooplankton’s ability to develop and reproduce, and higher trophic levels. The detrimental effects on marine ecosystems can be intensified by the interaction of ocean acidification, heat, deoxygenation, eutrophication, and pollution. Marine resources like fisheries and aquaculture are seriously threatened by ocean acidification and climate change, which might have negative social and economic effects. Reducing CO2 emissions, preserving and repairing marine habitats, and putting sustainable resource management techniques into practice are some ways to deal with these problems.
Continue reading ‘The silent shift: how ocean acidification and rising temperature affect marine organisms’Seaweeds (Ulva, Gracilaria) significantly increase the growth rates of North Atlantic oysters, scallops, and clams grown in an aquaculture setting
Published 17 February 2026 Science ClosedTags: algae, biological response, BRcommunity, chemistry, fisheries, laboratory, mitigation, mollusks, morphology
Highlights
- Seaweeds significantly increased the growth rates of oysters by 20–70%, of clams by 60–70%, and of scallops by 130–140%.
- Seaweeds caused significant increases in pH, DO, and the saturation state of calcium carbonate (Ω).
- Seaweeds caused a significant increase in the concentrations of suspended chlorophyll a.
- Co-culture of seaweeds with bivalves accelerates the growth rate of bivalves by increasing pH, DO, Ω, and food availability.
Abstract
While bivalve populations are threatened by climate change stressors including ocean acidification and hypoxia, the photosynthetic activity of seaweeds can raise the pH and dissolved oxygen (DO) of seawater, combatting these stressors. Here, three commercially important North Atlantic bivalves (Eastern oysters, Crassostrea virginica; hard clams, Mercenaria mercenaria; bay scallops, Argopecten irradians) were grown in the presence and absence of two common seaweeds (Ulva sp. and Gracilaria sp.) in replicated 300 L outdoor aquaculture tables with flow-through seawater. Environmental conditions including pH, DO, and chlorophyll a were continuously monitored and levels of dissolved inorganic carbon and the complete carbonate chemistry of seawater were quantified. The presence of seaweeds significantly increased shell- and tissue-based growth rates of oysters by 20–70%, of clams by 60–70%, and of scallops by 130–140% (p < 0.05) with both seaweeds being similarly effective. Both seaweed species caused significant increases in pH, DO, and the saturation state of calcium carbonate (Ω) during the day (p < 0.05) whereas differences at night were muted with night-time Ωaragonite levels being at or below saturation in all treatments. In some experiments, the presence of seaweeds caused a significant increase in the concentrations of suspended chlorophyll a, suggesting that seaweeds increased the total amount and diversity of food available to bivalves. Collectively, this study demonstrates that the co-culture of seaweeds with bivalves in a land-based aquaculture setting can significantly accelerate the growth rate of bivalves by increasing pH, DO, Ω, and food availability.
Continue reading ‘Seaweeds (Ulva, Gracilaria) significantly increase the growth rates of North Atlantic oysters, scallops, and clams grown in an aquaculture setting’Metabolic rate measurements of two benthic invertebrates under simulated climate change conditions
Published 16 February 2026 Science ClosedTags: adaptation, biological response, laboratory, Mediterranean, mollusks, morphology, multiple factors, otherprocess, porifera, respiration, temperature
Climate change is profoundly altering marine ecosystems through ocean warming and acidification. These stressors are especially pronounced in the Mediterranean Sea, a climate change hotspot projected to warm faster than the global average. Increased temperatures and reduced pH directly affect metabolic processes in marine invertebrates by elevating respiration rates up to species-specific thermal limits, beyond which physiological performance declines. Ocean acidification further disrupts metabolic processes by increasing energetic maintenance costs. Sessile and sedentary marine invertebrates, such as sponges and benthic gastropods, are particularly exposed to such environmental shifts due to their limited ability to escape unfavorable conditions, making physiological plasticity and local adaptation crucial for persistence.
This manuscript presents a dataset of oxygen consumption rates and wet weight measurements for two low-mobility marine species, the gastropod Hexaplex trunculus and the sponge Chondrilla nucula. Using a common garden experiment, individuals from North and South Aegean populations were exposed for three months to simulated climate change conditions combining increased temperature and reduced pH. The dataset documents respiration measurements obtained using metabolic chambers after three months of exposure, allowing comparisons across species, geographic origin, and experimental treatments.The dataset accounts for intraspecific variation in these responses, providing insight into potential adaptive differences among geographically distinct populations. These data provide a resource for future analyses of metabolic responses of marine invertebrates to combined warming and acidification conditions.
Continue reading ‘Metabolic rate measurements of two benthic invertebrates under simulated climate change conditions’Carbon concentration mechanisms in Canary Islands macroalgae and their implications for future benthic community structure under ocean acidification
Published 12 February 2026 Science ClosedTags: algae, biological response, BRcommunity, community composition, laboratory, North Atlantic, otherprocess, physiology, primary production, respiration, vents
In recent decades, due to the anthropogenic CO2 concentration increase in the atmosphere, the chemistry of seawater has been seriously altered, producing the phenomenon known as Ocean Acidification (OA). Of all the dissolved inorganic carbon (DIC) present in seawater, only 1% is in the form of CO2. However, if anthropogenic CO2 emissions to the atmosphere continue, it will no longer be a limiting resource. Part of the response of marine photosynthetic organisms to these changes depends on their carbon physiology. The presence and effectiveness of carbon concentration mechanisms (CCM) can define the production and growth of macroalgae under OA conditions. Although CCMs are not essential when the seawater concentration of inorganic carbon is high, species that do not use them can see their performance improved. Our goal was to determine the presence or absence of CCMs in a total of 19 species of common macroalgae in the Canary Islands through a pH drift experiment and to establish their primary production rates through incubations and measurements of the O2 variation. Samples of each species were incubated during 8, 24 and 32 h in isolated containers and under controlled lighting and temperature conditions. Of the 19 species studied, 11 presented CCM and 8 did not present CCM. Five of the eight species that did not show the presence of CCMs in the present study are present in the CO2 seeps of Fuencaliente and one of them, H. scoparia is a dominant species.
Continue reading ‘Carbon concentration mechanisms in Canary Islands macroalgae and their implications for future benthic community structure under ocean acidification’A systematic review of the ocean acidification research in India: research trends, gaps and recommendations
Published 11 February 2026 Science ClosedTags: biological response, Indian, policy, review, useOAICCresource
Ocean acidification, a consequence of climate change, has become a significant threat to marine organisms. Globally, tremendous efforts have been made to understand its impact on different ecological and biological processes. In India, this research area is still not fully explored, but expanding at an exponential rate. Hence, it is essential to consolidate the fragmented knowledge into a systematic review, which will assist future researchers to develop their work. In this study, we utilized the Scopus, Web of Science and Ocean Acidification-International Coordination Centre bibliography to conduct a systematic review of ocean acidification research in India. We used the Biblioshiny package in R to conduct a bibliometric analysis, identify spatial and temporal research trends, and highlight the growth of literature in ocean acidification research, as well as existing knowledge gaps. We used the following keywords: ocean acidification, lowered pH, acidifying ocean, elevated carbon dioxide, elevated CO2, marine carbonate chemistry, shell decalcification and affiliation as India to obtain relevant publications. We selected 353 publications by applying relevance filtering and adherence to PRISMA guidelines. Almost one-third of the publications were non-primary articles. Among research articles, only 71 publications were found to investigate the response of marine organisms to ocean acidification. Majority of them involved single stressors, for a short term on very limited taxa. Lack of molecular-level investigation, multifactorial experimental design, and long-term observations were major gaps. This review aims to support researchers, policymakers, and other stakeholders involved in the planning, monitoring, and developing adaptation strategies. Finally, it provides recommendations for future research and policy development.
Continue reading ‘A systematic review of the ocean acidification research in India: research trends, gaps and recommendations’Summary of ocean acidification data collected by the National Coral Reef Monitoring Program in the U.S. Pacific Islands, 2021—2023
Published 10 February 2026 Newsletters and reports ClosedTags: biological response, BRcommunity, chemistry, corals, field, North Pacific, primary production
Coral reefs are among the most biologically diverse and economically valuable ecosystems on earth. They provide billions of dollars annually in food, jobs, recreation, coastal protection, and other critical ecosystem services (Brander & van Beukering, 2013; Costanza et al., 2014). However, these ecosystems are also among the most vulnerable to ocean acidification (OA). Even under the most optimistic model projections, increasing atmospheric and seawater carbon dioxide concentrations are likely to occur over the next few decades, decreasing seawater pH and reducing the availability of the carbonate ion (CO32-) building blocks that corals and other marine calcifiers use to construct reef habitat (Chan & Connolly, 2013; Jiang et al., 2023). OA threatens the persistence of coral reefs by reducing rates of coral and crustose coralline algae (CCA) calcification and accelerating rates of bioerosion, thereby lowering net production of calcium carbonate (CaCO3) and compromising the structural complexity and integrity of three-dimensional reef habitat (Cornwall et al., 2021; Hill & Hoogenboom, 2022). As a result, many of the ecological, economic, and cultural values offered by coral reefs could be significantly impacted by OA over the next century.
NOAA’s National Coral Reef Monitoring Program (NCRMP) provides a framework for long-term, national-level monitoring of the U.S.-affiliated coral reef areas. Funded jointly by the NOAA Coral Reef Conservation Program and Ocean Acidification Program, NCRMP assesses the status and trends of U.S. coral reef ecosystems and supports the management of the nation’s reefs (NOAA Coral Program, 2021). NCRMP’s long-term monitoring of OA and related coral reef ecosystem responses (NCRMP-OA) evaluates patterns and trends in carbonate chemistry and key ecosystem indicators across gradients of biogeography, oceanographic conditions, habitat types, and human impacts. These data sets are used to inform the efficacy of place-based coral reef management in close collaboration with federal, state, and jurisdictional partners.
To assess the progression of OA and impacts on coral reef ecosystems in the U.S. Pacific Islands, NCRMP-OA monitoring includes the following objectives:
- Conduct carbonate chemistry sampling to monitor spatial variability and temporal change in pH, aragonite saturation state (Ωar), and other carbon system parameters;
- Conduct diel carbonate chemistry water sampling and oceanographic instrument deployments at select sites;
- Conduct census-based carbonate budget assessments to estimate rates of coral reef biological carbonate production and erosion.
This report summarizes the monitoring effort and results from 2021–2023 NCRMP-OA sampling and surveys. Additional NCRMP environmental, benthic, and fish data are not included in this report, but they can be accessed at the links provided in the Data Availability section.
Continue reading ‘Summary of ocean acidification data collected by the National Coral Reef Monitoring Program in the U.S. Pacific Islands, 2021—2023’Microbial community dynamics over large spatial and environmental gradients in a subtropical ocean basin
Published 9 February 2026 Science ClosedTags: abundance, biogeochemistry, biological response, chemistry, community composition, field, molecular biology, North Atlantic, otherprocess, prokaryotes, protists
Microbes are fundamental to ocean ecosystem function, yet they remain understudied across broad spatial and environmental scales in dynamic regions like the Gulf of America/Gulf of Mexico (GOM). We employed DNA metabarcoding to characterize prokaryotes (16S V4–V5) and protists (18S V9) across 51 stations, spanning 16 inshore–offshore transects and three depths. Cluster analysis revealed three clusters corresponding to depth zones that integrated vertical and horizontal sampling: photic zone (inshore near surface–bottom and offshore surface), deep chlorophyll maximum (offshore), and aphotic zone (offshore near bottom). We applied group-specific generalized additive models (GAMs) to log-transformed abundance data of major taxa in the photic zone, identifying key environmental factors that explained 42%–82% of the variation in abundance. SAR11 and SAR86 were positively associated with temperature and dissolved inorganic carbon, while cyanobacterial genera (Prochlorococcus and Synechococcus) were differently impacted by nutrients, salinity, and pH in ways that often followed their expected ecological niches. Representatives of protist parasites (Syndiniales) and grazers (Sagenista) showed group-specific nonlinear associations with salinity, oxygen, nutrients, and temperature. Using GAMs, we expanded the spatial resolution of DNA sampling and predicted surface log abundances at 84 cruise sites lacking amplicon data. Indicator analysis was performed with sequence-level data, revealing several protists that were indicative of more acidic waters and the absence of any significant prokaryote indicators. Our results provide the first basin-scale survey of microbes in the GOM and highlight the need for coordinated omics and environmental sampling to improve predictions of microbial responses to changing conditions.
Continue reading ‘Microbial community dynamics over large spatial and environmental gradients in a subtropical ocean basin’Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates
Published 6 February 2026 Science ClosedTags: biological response, laboratory, Mediterranean, methods, mollusks, morphology, multiple factors, porifera, temperature
Over the past 50 years, the oceans have absorbed over 90% of global warming heat, leading to warming, acidification, and declining oxygen levels that are disrupting marine ecosystems and altering species distributions and productivity. The vulnerability of marine organisms to these changes depends on their biological traits, habitat conditions, and adaptive capacity, influencing their growth, behavior, and overall population health. Micro-computed tomography (micro-CT) has been previously used for studying the morphological traits of marine invertebrates, which provide important insights into species functionality and responses to climate change and ocean acidification. Micro-CT enables non-destructive, high-resolution 3D analysis of internal and external structures, allowing precise measurement of traits such as density, porosity, and morphology that are valuable for climate change research.
The present manuscript describes micro-CT imaging datasets generated to investigate the effects of climate change on the morphological structure of two low-motility benthic marine invertebrates: the gastropod Hexaplex trunculus and the sponge Chondrilla nucula. Both species are considered particularly vulnerable to environmental stressors. To date, no study has investigated the effects of ocean warming and acidification on sponges using micro-CT technology. Using a common garden experimental design, individuals from geographically distinct populations exposed to different natural environmental regimes were subjected to combined warming and acidification scenarios to assess their morphological responses and adaptive capacity.
Continue reading ‘Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates’Untargeted mass spectrometry to investigate ocean acidification in Cancer borealis using optimized metabolite extraction methods
Published 5 February 2026 Science ClosedTags: biological response, crustaceans, laboratory, methods, physiology
Ocean acidification (OA) refers to the ongoing decline in ocean pH caused by the cascading effects of increased atmospheric CO2, which has significant negative impacts on various marine organisms, particularly crustaceans with calcified shells. However, research on the metabolic responses of crustaceans remains limited. In this study, we performed untargeted metabolomics on hemolymph samples from Cancer borealis (Jonah crab), a crustacean species well known for its tolerance to temperature and pH changes, to investigate its metabolic responses to OA. Two extraction methods—isopropanol (IPA) and acidified methanol (AcMeOH)—were employed to capture a broad range of metabolites and small peptides. Both methods enabled comprehensive detection; however, IPA yielded more consistent and extensive metabolite coverage, identifying 43 lipids compared to only 15 with AcMeOH. We identified 15 metabolites that responded significantly to OA. Several metabolites, including the potential neuropeptide cycloprolylglycine and the exogenous compound curcumin, exhibited concentration changes under OA exposure, suggesting their potential relevance in stress response pathways triggered by environmental stress. Overall, we highlight IPA as a more effective extraction method for untargeted metabolomics in crustacean hemolymph. Our study elucidates metabolic dynamics that enhance our understanding of the physiological adaptability of marine crustaceans under environmental stress and provides a comprehensive dataset that for future OA research.
Continue reading ‘Untargeted mass spectrometry to investigate ocean acidification in Cancer borealis using optimized metabolite extraction methods’Resilience of the macroalgae Gongolaria barbata under ocean acidification: physiological responses and restoration perspective
Published 3 February 2026 Science ClosedTags: algae, biological response, laboratory, Mediterranean, mesocosms, morphology, photosynthesis, physiology, reproduction, respiration
The increasing CO2 concentration is a major cause of the climate change phenomenon. Concurrently, the same increase is leading to ocean acidification (OA), which is projected to decrease seawater pH by 0.4 units by 2100. Here we investigated the potential impacts of OA on the canopy-forming brown macroalga Gongolaria barbata from the Venice Lagoon. One-year-old individuals were maintained in mesocosms under two pH levels: 8.1 (current ambient value) and 7.7 (the end-of-the-century value predicted under the current scenario of anthropogenic CO2 emissions). The physiological responses of the algae were assessed during the experiment in terms of oxygen production and consumption, and maximal PSII photochemical efficiency. At the end of the experiment, we analyzed the percentage of mature receptacles, algal growth rate and the total polyphenolic content and antioxidant capacity as indicators of the stress response. The significant decrease in polyphenolic content indicates the impairment of the defence mechanisms, which could make the algae more vulnerable to grazing under acidified conditions. Yet, conversely, our results suggest that changes in pH levels do not significantly affect the physiological processes, growth or fertility of the algae. These findings suggest that while OA may weaken defence mechanisms, the preservation of physiological and reproductive functions would still support the potential of G. barbata populations from the Venice Lagoon to act as donor sources for restoration efforts, highlighting their resistance to the acidified conditions expected in the future.
Continue reading ‘Resilience of the macroalgae Gongolaria barbata under ocean acidification: physiological responses and restoration perspective’Parental exposure to ocean acidification impacts the larval development and transcriptome of the Pacific oyster Crassostrea gigas
Published 2 February 2026 Science ClosedTags: adaptation, biological response, growth, laboratory, molecular biology, mollusks, North Pacific, otherprocess, reproduction
Atmospheric carbon dioxide (CO2) levels are escalating at an unprecedented rate, leading to the phenomenon of ocean acidification (OA). Parental exposure to acidification has the potential to enhance offspring resilience through cross-generation plasticity. In this study, we analyzed larval growth and transcriptomic profiles in the Pacific oyster, Crassostrea gigas, a species of significant ecological relevance, under both control and elevated CO2 conditions experienced by their parental generation. Our findings indicate that the oyster populations exposed to OA exhibited a higher incidence of abnormalities during the D-shaped larval stage, followed by accelerated growth at the eyed stage. Through a comparative transcriptomic investigation of eyed larvae (25 d after fertilization), we observed that parental exposure to OA substantially influenced the gene expression in the offspring. Genes associated with lipid catabolism and shell formation were notably upregulated in oysters with parental OA exposure, potentially playing a role in cross-generational conditioning and conferring resilience to OA stressors. These results underscore the profound impact of OA on oyster larval development via cross-generational mechanisms and shed light on the molecular underpinnings of cross-generation plasticity.
Continue reading ‘Parental exposure to ocean acidification impacts the larval development and transcriptome of the Pacific oyster Crassostrea gigas’Photoaged microplastics disrupt the response of marine medaka (Oryzias melastigma) to ocean acidification: perspectives from energy metabolism and ammonia production
Published 2 February 2026 Science ClosedTags: biological response, fish, laboratory, molecular biology, multiple factors, North Pacific, physiology, plastics, respiration
Ocean acidification (OA) and microplastics (MPs, <5 mm) are co-occurring stressors that threaten marine ecosystems. Although the marine environment contains multiple pollutants, OA can alter the environmental behavior of MPs, influencing their toxicity and environmental fate. Therefore, investigating the interactive effects of OA and MPs is essential. Fish can activate physiological compensatory mechanisms to adapt to OA; however, it remains unclear how MPs affect these mechanisms. In this study, marine medaka were exposed to acidified seawater (pH 7.70) containing environmentally relevant concentrations of MPs (0.1 mg/L) for 90 days to investigate the disruptive effects of MPs on responses to OA. The results showed that while OA triggered compensatory energy metabolism reprogramming to enhance ammonia production, MPs disrupted this process, reducing the TCA cycle intermediate α-ketoglutarate. This α-ketoglutarate deficiency limited the glutamate supply for ammonia production. Simultaneous inhibition of glutamate dehydrogenase activity further limited glutamate availability. As a result, MPs reduced the level of ammonia production by 25.29%, compromising the ability to neutralize excess H+. Crucially, photoaging exacerbated this toxicity, leading to a 32.04% reduction in ammonia production. This study demonstrates that MPs interfere with fish responses to OA via α-ketoglutarate-mediated metabolic reprogramming, highlighting a vulnerability in marine organisms facing climate change scenarios.
Continue reading ‘Photoaged microplastics disrupt the response of marine medaka (Oryzias melastigma) to ocean acidification: perspectives from energy metabolism and ammonia production’Understanding coral health from reactor engineering perspective: multiphysics modeling of coral–environment interactions
Published 30 January 2026 Science ClosedTags: biological response, corals, individualmodeling, modeling, photosynthesis, physiology, respiration
Coral, as a bioreactor, has to continuously interact with surrounding environment to maintain a healthy state. A multi-physics reaction engineering model has been developed to capture this interaction. The coral interior is modeled as interconnected reaction units respectively for photosynthesis, respiration, and calcification, whose reaction kinetics are influenced by environmental fluctuations. Coupling between coral and environment is realized by bi-directional mass transfer at the coral-seawater interface, with consideration of the unique flow fields induced by ciliary beating. By resorting to this comprehensive model, we discover that ciliary beating demonstrates distinctively different diurnal and nocturnal functions. During daytime, beating can help reduce photosynthetic oxygen accumulation to prevent hyperoxia-induced mortality, while enhancing carbon dioxide uptake efficiency to promote nutrient production. At night, however, beating promotes oxygen acquisition for adequate respiration, while expelling carbon dioxide to inhibit symbiotic destruction under acidic stress. The model further enables mechanistic analysis of the detrimental impact of climate change on coral health, where the influences from two key factors (i.e., temperature and CO2 level) can be decoupled. It’s interesting to find out that the elevated temperature plays a dominant role during daytime, while at night the coral is dominantly influenced by rising CO2 level.
Continue reading ‘Understanding coral health from reactor engineering perspective: multiphysics modeling of coral–environment interactions’Triple threat: ocean acidification, warming, and hyposalinity synergistically weaken shell integrity in a Mediterranean calcifying mollusk
Published 30 January 2026 Science ClosedTags: biological response, fisheries, laboratory, Mediterranean, mollusks, morphology, mortality, multiple factors, salinity, temperature
Highlights
- OA, OW, and hyposalinity drive skeletal and mineralogical responses in a Mediterranean clam.
- Combined stress makes shells less dense, more porous, and more fracture-prone.
- Microstructural changes reveal early calcification impairments under triple stress.
- Triple-stressor synergy compromises shell integrity and threatens fishery species resilience.
Abstract
Anthropogenic climate change is rapidly altering marine environments primarily through ocean warming, acidification, and hyposalinity, posing significant challenges for marine calcifying organisms. This study investigated the short-term effects of these stressors on the Mediterranean bivalve Chamelea gallina, a key fishery species in the Adriatic Sea, by integrating skeletal, mechanical, and mineralogical responses. Adult clams of commercial size were exposed for 21 days to eight experimental treatments manipulating two levels of temperature (18 °C vs. 22 °C), pH (8.0 vs. 7.9), and salinity (35 vs. 32), chosen to reproduce near-future climate projections and the freshwater-driven variability typical of the Adriatic Sea. Despite the short exposure duration, the combined exposure to low pH, high temperature, and reduced salinity weakens the shell of Chamelea gallina at multiple levels, compromising shell integrity, by making shells less dense, more porous, more fragile, and more susceptible to fracture, and increasing mortality. Microstructural analysis revealed smaller aragonite crystallites and lower calcium content, indicative of early impairments in the calcification process. The study highlights the occurrence of synergistic effects among stressors and reveals the vulnerability of Chamelea gallina to near-future ocean conditions, with potential cascading consequences for ecosystem functioning and fishery sustainability, given the species’ key ecological role and commercial relevance in the Adriatic Sea.
Continue reading ‘Triple threat: ocean acidification, warming, and hyposalinity synergistically weaken shell integrity in a Mediterranean calcifying mollusk’Short-term tolerance to ocean acidification of the sub-antarctic sea-urchin arbacia dufresnii
Published 29 January 2026 Science ClosedTags: Antarctic, biological response, echinoderms, laboratory, molecular biology, morphology, physiology
The accumulation of anthropogenic CO2 in the ocean is impacting the carbonate system chemistry in seawater, particularly in polar regions. Acidified seawater can impair the echinoderms internal regulation of pH due to an increase in hydrogen ions concentration, potentially affecting growth, and calcification, among other physiological activities. The goal of this work was to assess the effects of Ocean Acidification (OA) on Arbacia dufresnii, a sub-Antarctic sea urchin species. Adult specimens were exposed to three pH treatments: 7.4, 7.7, and 8.0 (control), for 21 up to 23 days. We assessed spine regeneration, a proxy of calcification, by cutting spines at the base of the shaft and evaluating the magnesium content, height, and weight of the regenerated part. The coelomic fluid was sampled for pH assessment and magnesium and calcium content analysis. The RNA/DNA ratio, a proxy of metabolic activity, was assessed in the gonads and body walls. The spine regenerated weight was significantly correlated to regenerated height but not to treatments. The coelomic fluid pH (6.77 ± 0.34) did not differ between treatments (pANOVA = 0.15). No significant differences were observed between treatments regarding RNA/DNA ratio in both body wall (pANOVA = 0.65) and gonads (pKruskal-Wallis = 0.34), the spine regenerated height (pANOVA = 0.35) and Mg regenerate content (pANOVA = 0.58). Our results suggest that A. dufresnii owns physiological mechanisms to cope with OA conditions during short-term exposure.
Continue reading ‘Short-term tolerance to ocean acidification of the sub-antarctic sea-urchin arbacia dufresnii’
