Ocean warming (OW) and ocean acidification (OA) are expected to have wide-ranging consequences for populations in marine systems caused by organism-level responses at a range of life history stages, including early larval stages. The Atlantic sea scallop, Placopecten magellanicus, is an economically important bivalve species that may be vulnerable to ocean change, but larval responses remain unclear. While the effects of OW and OA are known to impact adult sea scallops, little is known about the interactive effects of these two factors on early life stages. Larval dispersal is key to population-level patterns (e.g. abundance and distribution), but is contingent on growth rates and vertical swimming behaviors, which are both influenced by environmental conditions. Here, we evaluate the combined effects of OW and OA on larval development and behavior in a factorial lab experiment. We maintained larval sea scallop cultures up to metamorphosis under a range of physico-chemical conditions (17℃ and 14℃, and pH 7.3, 7.6, 7.9). Sea scallop larval development time was temperature dependent (1 vs. 1.5 months). There was an interactive effect of OW and OA on growth, where OA limited gains in growth experienced in warmer conditions. OA limited a decline in distribution late in development, while OW dominated individual vertical swimming behavior in intermediate development. Finally, ΩAr growth sensitivity was intermediate compared to that of other bivalve taxa. These results contribute to an improved understanding of developmental and behavioral responses to OW and OA, and provide information necessary for improved larval dispersal models under ocean change.
Continue reading ‘Ocean warming and acidification alter larval development and swimming behavior in the Atlantic sea scallop, Placopecten magellanicus’Posts Tagged 'mollusks'
Ocean warming and acidification alter larval development and swimming behavior in the Atlantic sea scallop, Placopecten magellanicus
Published 13 October 2026 Science ClosedTags: biological response, growth, laboratory, mollusks, mortality, multiple factors, performance, reproduction, temperature
Differential gene expression reveals molecular mechanisms for physiological resilience to ocean acidification stress in native and introduced oyster species
Published 9 October 2026 Science ClosedTags: adaptation, biological response, fisheries, molecular biology, mollusks, North Pacific, otherprocess, physiology
Coastal-estuarine habitats are rapidly changing with respect to ocean acidification (OA). Along the West Coast of the United States, coastal upwelling regions are high in productivity and rich in nutrients, making them key areas for aquaculture oyster production. The native Olympia oyster Ostrea lurida has experienced population collapse due increased commercial harvest, habitat loss, and the introduction of the non-native Pacific oyster Magallana gigas. Despite intense focus on physiological responses of oysters to OA stress, molecular underpinnings of have yet to be fully described, particularly in niche species. Juvenile oysters of both M. gigas and O. lurida were exposed to a range of experimental OA conditions for six weeks to investigate transcriptomic and biomineralization responses under fluctuating and chronic low pH. Low pH had a significant effect on shell dissolution for both Pacific and Olympia oysters, with no statistical difference observed between the two species. Differential gene expression revealed distinct differences in responses of the Pacific and Olympia oysters to OA on the transcriptomic level, with M. gigas showing elevated molecular responses to OA stress. Our findings suggest that the two species may employ distinct adaptive strategies to mitigate low pH that are informative for species-specific management strategies.
Continue reading ‘Differential gene expression reveals molecular mechanisms for physiological resilience to ocean acidification stress in native and introduced oyster species’Carbon dynamics and water quality regulation in Ruditapes philippinarum-Chlorella vulgaris co-culture with cardiac monitoring
Published 8 October 2026 Science ClosedTags: algae, biological response, BRcommunity, chemistry, fisheries, mitigation, mollusks, North Atlantic, physiology
Highlights
- Clam addition rapidly altered nitrogen, oxygen and dissolved-carbon dynamics.
- All chamber treatments maintained negative CO₂ fluxes during incubation.
- Algal monoculture showed stronger 6-h CO₂ uptake than co-culture.
- Hydrochemical variables and cardiac activity were recorded concurrently.
Abstract
Global warming and ocean acidification threaten marine aquaculture. Bivalve-microalgae co-culture is considered a promising approach for low-carbon aquaculture, but its effects on water quality, carbon dynamics and bivalve physiology are not fully understood. This study tested Ruditapes philippinarum and Chlorella vulgaris in sealed static chambers with three treatments: sterile seawater (NP-C), Chlorella monoculture (WP-C) and clam-Chlorella co-culture (WP). Water-quality variables, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), air-water CO₂ flux and clam heart rate were measured in separate 3-h and 6-h incubations. At the end of incubation, WP had higher ammonium concentrations and lower dissolved oxygen than WP-C, indicating that clam addition changed nitrogen and oxygen conditions. DOC and DIC also changed differently in the two biological treatments. All treatments showed negative air-water CO₂ fluxes. In the 6-h experiment, CO₂ uptake was strongest in WP-C and intermediate in WP. Heartbeats were recorded continuously in four clams for 7.07 h. Overall, the co-culture rapidly altered water-quality and dissolved-carbon dynamics but did not result in greater short-term CO₂ uptake than the algal monoculture under the present chamber conditions.
Continue reading ‘Carbon dynamics and water quality regulation in Ruditapes philippinarum-Chlorella vulgaris co-culture with cardiac monitoring’Long-term exposure to ocean acidification modifies the biochemical composition of the adductor muscle of the commercial scallop Zygochlamys patagonica
Published 7 October 2026 Science ClosedTags: biological response, fisheries, mitigation, mollusks, physiology, South Atlantic
The scallop Zygochlamys patagonica is an ecologically and economically important seafood species in the Southwest Atlantic Ocean that has been shown to be sensitive to ocean acidification (OA), a global process caused by anthropogenic carbon dioxide emissions. This study experimentally evaluated the effects of a long-term exposure to low pH, including an OA scenario on the scallop adductor muscle— the commercially valuable tissue. We tested three levels of pH, two pH values within the present range of natural variability (high pHT= 8.00 and medium pHT= 7.80) and a lower pH level representing a true OA scenario (low pHT: 7.52). We examined biochemical alterations induced by low pH and assessed the potential for reversibility following a depuration period. No significant effects were observed for medium pH exposure. However, after 14 and 28 weeks of exposure to low pH (OA), significant reductions in protein and total lipid content were observed, resulting in decreased overall energy reserves, while glycogen levels remained unchanged. The fatty acid profile shifted under OA with an increased PUFA/ SFA ratio and higher sums of EPA and DHA. No signs of recovery were detected after the 2-month depuration period. These results indicate that OA-driven changes in biochemical composition may reflect altered physiological status, with potential socio-ecological implications for the sustainable exploitation of this valuable resource.
Continue reading ‘Long-term exposure to ocean acidification modifies the biochemical composition of the adductor muscle of the commercial scallop Zygochlamys patagonica’Single-larva transcriptomics resolve phenotype-anchored Na+ K+ ATPase expression during first shell formation in Pacific oyster larvae under ocean acidification conditions
Published 5 October 2026 Science ClosedTags: biological response, laboratory, methods, molecular biology, mollusks, physiology
Bivalve larvae are highly sensitive to ocean acidification (OA) conditions, a global climate shift that applies selective pressure on calcareous marine organisms. Although a growing body of work exists on the effects of OA on bivalve larvae, most studies rely on pooled-larval sampling, which may obscure gene expression patterns by including larvae with severely underdeveloped or deformed phenotypes, which are common in OA conditions but are unlikely to survive to metamorphosis. Here, we tested a combination of single-larva transcriptomic techniques to investigate the expression of a candidate gene previously shown to be upregulated in OA conditions, Na+ K+ ATPase (NKA), in Pacific oyster larvae of known phenotypes. We found that upregulation of the NKA gene is detected primarily in larvae with a developed first shell (prodissoconch I), and was not pronounced in underdeveloped or deformed larvae, suggesting its expression reflects active shell formation under OA conditions, rather than a generalized stress response. Further, NKA mRNA was primarily localized along the dorsal shell hinge, the site of CaCO3 deposition, substantiating its role in early shell development. This study provides a methodological framework for phenotype-anchored sampling to investigate the expressional signatures underpinning successful shell development in OA conditions.
Continue reading ‘Single-larva transcriptomics resolve phenotype-anchored Na+ K+ ATPase expression during first shell formation in Pacific oyster larvae under ocean acidification conditions’Involvement of CgPGC-1α in regulating mitochondrial biogenesis in Pacific oyster Crassostrea gigas under ocean acidification
Published 5 October 2026 Science ClosedTags: adaptation, biological response, fisheries, laboratory, molecular biology, mollusks, multiple factors, otherprocess, physiology, temperature
Highlights
- CgPGC-1α with classical RRM domain was identified from Crassostrea gigas.
- CgPGC-1α mRNA was ubiquitously expressed with the highest level in gill.
- CgPGC-1α could respond to acidification treatment, promote mitochondrial biogenesis.
- Acidification enhanced mitochondrial biogenesis and ATP via AMPKα/PGC-1α.
Abstract
Ocean acidification poses a significant threat to calcifying marine organisms. The Pacific oyster Crassostrea gigas is an economically and ecologically important bivalve species. Understanding the molecular mechanisms underlying its physiological adaptation to acidification stress is therefore of great ecological and aquaculture relevance. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a central regulator of mitochondrial biogenesis and cellular energy metabolism, which plays important roles in response to various stressors. In this study, a PGC-1α homolog was identified from Crassostrea gigas (CgPGC-1α), which harbors an evolutionarily conserved RRM domain. The phylogenetic tree indicated that CgPGC-1α first clustered with PGC-1α from molluscs, then grouped with vertebrate PGC-1α, and finally joined with the PGC-1α of arthropods. During larval development, expression level of CgPGC-1α increased from the early embryonic stages, reached its highest level at blastula stage, and subsequently decreased during later development stages. In adult oysters, expression level of CgPGC-1α were detected in haemocytes and all examined tissues, with the highest level in gills. When the oysters were exposed to acidified seawater at pH 7.4, the expression level of CgPGC-1α in gonad was significantly upregulated at 7 and 21 days. Furthermore, at 7 days after acidification treatment, the mtDNA copy number, the expression level of CgMFN mRNA transcripts, the CgPGC-1α protein levels and the pAMPKα (Thr172) phosphorylation levels all significantly increased (p < 0.05), while the relative mRNA expression level of CgDRP1 significantly decreased (p < 0.05). Moreover, a significant increase in the number of mitochondria with morphology changing from elliptical to irregular and cristae becoming swollen was observed, and the ATP content was significantly elevated. After 28d days of acidification, mtDNA copy number and the expression level of CgMFN and CgNRF2 were significantly decreased, whereas the expression level of CgDRP1 was significantly increased. Collectively, these findings reveal a temporal response to acidification, characterized by an early compensatory activation of the AMPKα/PGC-1α axis and enhanced mitochondrial biogenesis, followed by impaired mitochondrial homeostasis under prolonged acidification stress. This study provides new insights into the molecular mechanisms underlying oyster resilience to ocean acidification and highlights the potential importance of mitochondrial adaptation in coping with future environmental changes.
Continue reading ‘Involvement of CgPGC-1α in regulating mitochondrial biogenesis in Pacific oyster Crassostrea gigas under ocean acidification’Ocean acidification remodels the mantle phosphoproteome and weakens shell mechanical resilience in Mytilus edulis
Published 2 October 2026 Science ClosedTags: biological response, laboratory, molecular biology, mollusks, morphology, North Pacific, physiology
Highlights
- Ocean acidification causes pH- and time-dependent disruption of nacreous and prismatic microstructures.
- Shell compressive strength declines progressively with decreasing pH and exposure duration.
- Quantitative mantle phosphoproteomics identified 3720 phosphoproteins and 10,780 phosphosites.
- Differential phosphorylation is associated with signaling, vesicular trafficking, autophagy, and metabolic pathways.
- Molecular and shell-level responses support a proof-of-concept dual-indicator framework.
Abstract
Ocean acidification (OA), driven by rising atmospheric CO2, threatens the structural integrity and ecological performance of calcifying marine organisms, yet the mechanistic links between environmental acidification and compromised shell mechanical resilience remain insufficiently understood. Here, we integrate microstructural imaging, mechanical testing, and quantitative phosphoproteomics to characterize the structural, mechanical, and phosphorylation responses of Mytilus edulis to OA and examine their relationships. Adult mussels were exposed to near-future pH conditions (8.1, 7.9, 7.7) for up to 40 days. OA produced progressive disorganization of nacreous tablets and prismatic columns without altering aragonite–calcite polymorphs, indicating that acidification drives structural degradation rather than mineralogical shifts. Correspondingly, shell compressive strength declined in a pH- and time-dependent manner, with an approximately 60% reduction at pH 7.7 after 40 days. Phosphoproteomic profiling identified 3720 phosphoproteins (10,780 sites), revealing extensive acidification-induced remodeling of phosphorylation networks. Proteins corresponding to differentially phosphorylated peptides were predominantly nuclear and were enriched in kinase-, PH-, PDZ-, and RNA-recognition-domain-containing proteins. Functional analyses implicated MAPK signaling, vesicular trafficking, ion transport, glycolysis/gluconeogenesis, autophagy, and calcium-associated processes. Phosphoproteomic remodeling was associated with the deterioration of shell microstructure and compressive strength, supporting an association between mantle phosphorylation responses and compromised biomineralization under acidification. The enriched pathways and protein domains were functionally related to calcium-dependent signaling, vesicular trafficking, cytoskeletal organization, and cellular metabolism, providing testable candidates for future mechanistic validation. Together, these findings support a working model in which ocean acidification is accompanied by coordinated phosphorylation remodeling and progressive loss of shell mechanical resilience. We further propose a proof-of-concept dual-indicator framework that integrates candidate molecular sentinels with organismal metrics, providing a conceptual basis for future assessment of aquaculture resilience and ecosystem vulnerability under progressive ocean acidification.
Graphical abstract
Survival costs flavor: microplastics reprogram metabolic resource allocation and compromise oyster quality under ocean acidification
Published 30 September 2026 Science ClosedTags: biological response, fisheries, laboratory, molecular biology, mollusks, multiple factors, North Pacific, physiology, plastics
Ocean acidification (OA) and microplastic (MP) pollution are widespread marine stressors, yet their interactive effects on seafood quality and molecular metabolism remain unclear. This study investigated the combined effects of OA (pH 7.7) and MPs (2 and 200 μg/L) on the Pacific oyster (Magallana gigas). OA was the primary driver of textural deterioration, significantly reducing springiness and chewiness, while combined stress synergistically depleted protein and lipid reserves. Distinct lipid remodeling strategies were identified: OA induced DHA accumulation potentially associated with membrane stabilization, whereas MPs triggered EPA and ARA upregulation associated with stress and immune responses. The flavor profile was severely compromised, characterized by depletion of umami amino acids, nucleotide redistribution, and altered succinate contribution. Transcriptomic analysis revealed that high MP exposure activated genome maintenance and DNA repair-associated pathways, including the Fanconi anemia pathway, superimposed on OA-associated metabolic suppression. Concurrent upregulation of nucleotide salvage (APRT, HPRT) and amino acid catabolic genes (GLS, GDH) suggests increased utilization of flavor metabolites for energetic demands. These findings support a bioenergetic trade-off in which oysters exposed to OA and MPs reallocate resources from nutritional and sensory quality toward cellular maintenance and stress adaptation, highlighting underrecognized consequences of climate change and plastic pollution for seafood quality.
Asymmetric metabolic responses of rockweed and herbivores reveal seasonal vulnerabilities to warming and acidification
Published 22 September 2026 Science ClosedTags: algae, biological response, BRcommunity, calcification, mollusks, multiple factors, photosynthesis, respiration, temperature
Macroalgal-herbivore interactions are fundamental to the stability of coastal ecosystems and their vulnerability to climate-driven shifts will affect biodiversity and ecosystem functioning. However, the effects of climate change on species interactions may be context dependent and vary by seasonal oceanographic processes. We examined the effects of warming and acidification on an intertidal primary producer foundation species, Silvetia compressa, and its herbivore, Agathistoma eiseni, under differing upwelling regimes in early (low upwelling) and late spring (high upwelling). We measured metabolic rates including photosynthesis, respiration, and calcification after four weeks of exposure to a range of nine pH levels (7.2–8.0) at two temperature levels (16°C, 20°C). Rockweed responded more to acidification than to warming, but showed different seasonal responses, decreasing photosynthetic rates in early spring and increasing rates during late spring. Their snail consumer, however, responded most strongly to temperature, increasing both respiration and calcification rates under warm conditions in late spring. Our findings demonstrate that seasonal differences can modulate responses of macroalgae and herbivores to changing environmental conditions. Warming may increase top-down effects through increased snail metabolism, while acidification affects rockweed production to affect bottom-up forcing. By assessing physiological responses across different ecological regimes, our study advances understanding of how top-down and bottom-up processes interact in intertidal ecosystems under global change.
Continue reading ‘Asymmetric metabolic responses of rockweed and herbivores reveal seasonal vulnerabilities to warming and acidification’TNF-NF-κB signaling mediates immune-biomineralization crosstalk during shell repair under ocean acidification in Mytilus edulis
Published 17 September 2026 Science ClosedTags: biological response, laboratory, molecular biology, mollusks, morphology, North Pacific, physiology
Highlights
- Day-15 shell closure ≠ functional repair: pH 7.7 disrupts microstructure, delays crystallization, and causes ∼87% strength loss.
- Hemocytes: early divergence (pH 7.9 inflammatory vs. pH 7.7 stress), late convergence with weak effectors; mantle upregulates immunity, suppresses OXPHOS/ECM.
- TNF-NF-κB (TNFSF14/TRAF6/IκBα) mediates immune-mineralization crosstalk, linking immunity to repair impairment.
- Multi-tissue dysregulation causes repair failure – not a single bottleneck, but decoupling of recruitment from deposition.
Abstract
Ocean acidification (OA) impairs biomineralization in bivalves, but its effects on immune-biomineralization crosstalk during shell repair remain unknown. Here, we exposed adult Mytilus edulis bearing standardized shell perforations to three pH levels (8.1, 7.9, and 7.7) for up to 40 days. OA slowed early repair and caused microstructural disorganization and an approximately 87% reduction of compressive strength at pH 7.7, yet the damaged area appeared largely closed by day 15, suggesting a decoupling between morphological closure and functional recovery. In addition, transcriptomic profiling of hemocytes and mantle tissue, based on an average of 6.5 Gb of clean reads per sample mapped to the M. edulis reference genome (NCBI Assembly GCF_000511035.1), revealed that these shell-level defects were accompanied by coordinated immune and metabolic reprogramming. Hemocytes, the primary immune effector cells of bivalves, exhibited pH- and time-dependent shifts with moderate acidification (pH 7.9) promoting inflammatory transcripts, whereas severe acidification (pH 7.7) suppressed these signals while upregulating stress-associated pathways; both treatments consistently downregulated lysosomal proteases and NF-κB negative regulators. The mantle, a primarily mineralizing organ, paradoxically upregulated immune-related genes while suppressing oxidative phosphorylation and extracellular matrix pathways. This tissue-level imbalance, with hemocytes recruited but functionally constrained and mantle metabolically suppressed yet immunologically activated, points to TNF-NF-κB pathway modulation as a key mediator of shell repair under acidification. Our findings demonstrate that visible shell closure masks underlying structural and mechanical failure, and that immune regulation, rather than simple suppression or activation, critically shapes the repair outcome. These results advocate for multifunctional indicators beyond closure area to assess shell integrity in acidified marine environments.
Continue reading ‘TNF-NF-κB signaling mediates immune-biomineralization crosstalk during shell repair under ocean acidification in Mytilus edulis’Brood chamber carbonate chemistry in the oyster Ostrea edulis is dynamically shaped by warming, acidification, and ventilation
Published 14 September 2026 Science ClosedTags: biological response, BRcommunity, laboratory, mollusks, performance, physiology, reproduction
Brooding organisms can modify the chemical environment experienced by developing offspring, potentially altering their exposure to climate change. In marine systems, however, the carbonate chemistry of brood chambers, and the mechanisms governing it, remain poorly resolved. Here, we combine high-resolution pH and CO2 measurements of the empty brood chamber (i.e., mantle cavity above gills) in the European flat oyster (Ostrea edulis) while also tracking valve gape to quantify how warming, ocean acidification, and ventilation interact to shape the internal environment experienced by larvae during incubation. Brood chamber pH was consistently lower than that of the surrounding seawater and responded to external conditions in a state-dependent manner governed by ventilation and respiration. When oysters were actively ventilating, brood chamber chemistry tracked ambient seawater with a persistent offset, whereas valve closure led to rapid CO2 accumulation and pronounced declines in pH. These dynamics generated highly variable and behaviorally mediated exposure regimes, in which metabolic processes distorted ambient chemical signals over short timescales. Paired pH and CO2 measurements provided preliminary constraints on aragonite saturation state (Ωar), revealing that brood chambers can remain undersaturated (Ωar < 1) for prolonged periods even in ventilating oysters and while overlying seawater remains favorable. Together, these results demonstrate that brood chambers function as dynamic microenvironments in which larval exposure to ocean acidification is governed not only by external conditions, but also by behavior. Because warming enhances metabolic CO2 production and intensifies acidification within the chamber, future climate change is likely to amplify both the magnitude and variability of larval exposure. These findings help explain the apparent resilience of brooding species to ocean acidification, while also highlighting potential limits as environmental conditions move beyond historical bounds.
Continue reading ‘Brood chamber carbonate chemistry in the oyster Ostrea edulis is dynamically shaped by warming, acidification, and ventilation’Ocean acidification and nanoplastics disrupt mussel calcification in synergy: a multi-omics analysis
Published 14 September 2026 Science ClosedTags: biological response, calcification, laboratory, molecular biology, mollusks, multiple factors, North Pacific, physiology, plastics
Highlights
- Ocean acidification disrupts calcium homeostasis in the mantle of mussels.
- Ocean acidification and N-NPs together intensify the inhibition of calcification.
- Surface charge determines distinct, mechanism-specific response pathways.
- Both omics reveal key roles for calcium transport, CA, and ECM synthesis.
Abstract
Ocean acidification (OA) and nanoplastics (NPs) increasingly co-occur in coastal ecosystems, yet their combined mechanistic impacts on calcifying invertebrates remain poorly resolved. Here, the mussel Mytilus coruscus was exposed for 30 days to factorial combinations of OA (pH 7.7 vs 8.1), surface-modified polystyrene NPs at a concentration of 100 μg/L (positively and negatively charged), and experimental shell damage to assess effects on shell repair, ion homeostasis, and energy metabolism. OA reduced shell repair quality by thinning repair layers, increasing porosity, and lowering calcium content, effects that were further enhanced by co-exposure to NPs, particularly negatively charged particles. OA and NPs jointly altered Ca2+ and Mg2+ levels, alkaline phosphatase activity, Ca2+Mg2+-ATPase activity, and key indicators of energy metabolism, including ATP content and cellular energy allocation. Transcriptomic and proteomic analyses revealed enrichment of ion transport, extracellular matrix, TGF-β signaling and other pathways, with divergent patterns linked to NPs surface charge. Together, these results suggest that nanoplastic surface charge under OA may impair mussel shell repair through associated alterations in ion homeostasis and energy metabolism. These findings highlight that particle surface properties shape how organisms respond to combined environmental stressors in acidifying marine environments.
Continue reading ‘Ocean acidification and nanoplastics disrupt mussel calcification in synergy: a multi-omics analysis’Chapter 23 – Climate change: effects and implications
Published 10 September 2026 Science ClosedTags: fisheries, mollusks
The coastal zone is an epicenter of climate change impacts, including rising sea levels, an increase in sea temperature, and a decrease in salinity through precipitation and ice melt. In addition, changes in carbon chemistry will result in the “acidification” of seawater. Direct physiological effects of extreme weather events will likely cause some sub-optimal changes in Manila clam abundance, with implications for aquaculture production, especially in warmer waters such as the Adriatic and the west coast of the Korean penisula. Indirect effects on food and predator species and synergistic impacts of multiple pollutants may also prove influential. Currently predicted acidification will, in itself, be within the tolerances of R. philippinarum, although it may contribute to increased oxidative stress and energetic demand, especially when in combination with other challenges. Overall, while Manila clam distributions, locally, regionally, and globally, will adjust, the species is considered resilient within temperate conditions and is expected to extend its global distribution northwards in Alaska, Europe, and probably Siberia.
Continue reading ‘Chapter 23 – Climate change: effects and implications’Environmental regulation and disruption of shell biomineralization in bivalves and gastropods: a mechanistic review
Published 10 September 2026 Science ClosedTags: biological response, molecular biology, mollusks, physiology, reproduction, review
Molluscan shells are increasingly threatened by a complex array of environmental stressors—climate-related drivers, changes in seawater chemistry, contaminants, and biotic cues. This review provides a mechanistic synthesis of how these stressors disrupt the biomineralization process across life stages. We develop a conditional hierarchical response framework from the reviewed evidence. The framework links ionoregulatory and acid-base disturbances with molecular, microstructural, and shell-level responses, while allowing for compensatory, nonlinear, species-specific, and life-stage-specific outcomes. This molecular disruption manifests as defects in calcium carbonate (CaCO3) crystalline microstructure, which may in turn compromise shell macro-scale physical properties (strength, hardness, growth). We synthesize combined and context-dependent effects of co-occurring stressors and distinguish formally tested interactions from qualitative comparisons of combined treatments. Future research must leverage integrated multi-omics, advanced in vivo imaging, and multi-stressor experimental designs to unravel candidate molecular and physiological thresholds and predict adaptive potential. This framework may help identify testable mechanisms, evidence gaps, and context-dependent vulnerabilities relevant to conservation.
Highlights
- A conditional framework links molecular, microstructural, and shell-level responses.
- Early stages often show high sensitivity, although direct ontogenetic comparisons remain limited.
- Energy limitation is a recurrent, but often indirectly inferred, physiological constraint.
Elevated pCO2 impairs overall byssus attachment strength in the blue mussel (Mytilus edulis) without altering byssus thread quality
Published 8 September 2026 Science ClosedTags: biological response, BRcommunity, laboratory, mollusks, North Atlantic, physiology
Increasing atmospheric carbon dioxide (CO2) is driving global ocean acidification (OA). This process may threaten the persistence of bed-forming mussels by weakening the byssal system that anchors them to the seafloor. Here, blue mussels (Mytilus edulis) were exposed to present-day (∼460 ppm pCO2) normocapnic and projected end-century (∼1200 ppm pCO2) hypercapnic conditions for four weeks at 12 °C. Byssus production, thread morphology, whole-byssus mechanics and the underlying physiological condition index (CI) were quantified. Unlike previous studies, this study analysed the byssus as an intact functional unit. This approach better reflects its mechanical performance in situ. Median thread production fell by 50% under elevated pCO2 and the number of individuals producing no threads at all increased from 3% to 23% of the population. Thread diameter and plaque area were unaffected. Whole byssus tensile testing revealed a distinctive mechanical pattern (elastic loading, force plateau, and structural failure) regardless of environmental CO2 concentration. Whole byssus attachment strength scaled linearly with thread number in both treatments, and the mechanical work required to detach mussels under hypercapnia dropped by 42%. Elevated pCO2 reduced mussel condition index by 19% relative to the control, indicating an energetic burden. These results show that near-future ocean acidification weakens mussel attachment primarily by lowering individual physiological condition, which directly drives the reduction in total attachment energy, rather than by lowering individual thread quality. This likely results from a shift in energy use away from thread production, as seen in poorer mussel condition. As a result, mussels may become more prone to being dislodged by waves or predators. The findings of this study indicate that ocean acidification can reduce the overall strength of M. edulis beds, with important effects on rocky shore ecosystems and the viability of mussel farming in a changing climate.
Continue reading ‘Elevated pCO2 impairs overall byssus attachment strength in the blue mussel (Mytilus edulis) without altering byssus thread quality’Biological impacts of ocean change in upwelling systems: from organismal responses to fishery outcomes
Published 3 September 2026 Science ClosedTags: arthropoda, biological response, calcification, crustaceans, echinoderms, fisheries, laboratory, mollusks, mortality, physiology
Climate change is altering marine ecosystems through concurrent changes in temperature, carbonate chemistry, and dissolved oxygen. These changes are particularly important in coastal upwelling systems, where organisms already experience naturally variable environmental conditions. This dissertation integrates synthesis, experimentation, and modeling to evaluate how ocean change influences marine invertebrates and the fisheries they support. First, I conducted a meta analysis examining the effects of ocean acidification and deoxygenation on marine invertebrates. Both stressors produced broadly negative effects on fitness-related
traits, including survival, growth, development, and reproduction. Although vulnerability varied among taxa, responses were not strongly structured across broad taxonomic groups, suggesting that species-specific traits and environmental history are important determinants of sensitivity. Second, I investigated the effects of multi-stressor upwelling conditions on juvenile Dungeness crab (Metacarcinus magister). Crabs maintained net calcification across a range of moderate conditions but exhibited significant declines under the most severe treatments, indicating threshold responses to environmental stress. Short-term environmental variability had little effect relative to mean conditions, suggesting that exposure severity is a stronger driver of performance than exposure pattern. Finally, I incorporated experimentally observed reductions in calcification into a size-structured yield-per
recruit model to evaluate potential fishery consequences. Reduced growth delayed attainment of legal harvest size and decreased projected fishery yield, demonstrating how sublethal physiological responses can scale to population and management-relevant outcomes. Together, these chapters show that ocean change can affect biological systems across levels of organization, from individual performance to fishery productivity. By linking broad patterns of vulnerability to species-specific responses and applied fishery outcomes, this dissertation provides a framework for understanding and managing the impacts of global change in coastal
marine ecosystems.
Climatic factors effects on gastropods (Phylum: Mollusca): a review of the biodiversity of freshwater, marine, and terrestrial snails
Published 1 September 2026 Science ClosedTags: biological response, mollusks, review
Climate change is altering ecosystems worldwide through rising temperatures, changing precipitation patterns, and more frequent extreme weather events, including heatwaves. Gastropods in freshwater, marine, and terrestrial environments are affected through changes in habitat characteristics, geographic distribution, abundance, physiology, and behavior. In freshwater systems, warming and drought can reduce dissolved oxygen and shrink suitable habitats. In marine environments, ocean acidification can impair shell formation and, under severe conditions, dissolve calcium-carbonate shells. In terrestrial habitats, increasing temperature and declining soil moisture can force snails into prolonged inactivity and increase desiccation risk. Effective climate information, predictive models, and early-warning systems are therefore essential for climate resilience, biodiversity conservation, and disease-risk management. Further comparative research is needed to clarify how phylogenetic history and adaptive variation influence heat tolerance and resilience among gastropod taxa.
Continue reading ‘Climatic factors effects on gastropods (Phylum: Mollusca): a review of the biodiversity of freshwater, marine, and terrestrial snails’Biological modulation of shell δ13C in Mytilus galloprovincialis and Phorcus sp.: divergent responses between CO2 vents and laboratory mesocosms
Published 17 August 2026 Science ClosedTags: biological response, BRcommunity, field, laboratory, Mediterranean, mesocosms, mollusks, physiology, vents
table isotopes are fundamental proxies for deciphering past environmental conditions and carbon cycle perturbations. However, applying these geochemical tools with a forward-looking perspective can also help predict the resilience of marine biota in future acidified oceans. This study investigates carbon uptake and biomineralization pathways under reduced pH in two ecologically keystone calcifying species: the bivalve Mytilus galloprovincialis and the gastropod Phorcus sp. To unravel these mechanisms, we adopted a dual approach, comparing isotopic trajectories (δ13C) under strictly controlled laboratory mesocosms with observations from natural CO2 vent systems in Ischia, Italy. Our results reveal a striking discrepancy between settings. Under laboratory conditions, both species exhibited a significant depletion in shell δ13C as pH decreased, directly tracking seawater carbonate chemistry. Conversely, specimens from the volcanic vents displayed a paradoxical δ13C enrichment at low-pH sites (pH ~7.4). These divergent trajectories indicate that in complex natural environments, the geochemical signal of ocean acidification can be overridden by metabolic overprints and trophically driven vital processes. Consequently, while laboratory experiments are essential to isolate kinetic fractionation, natural analogues remain crucial to capture the biological resilience and complex ecological feedback of future oceans. Future research combining these geochemical trends with direct, in vivo physiological assessments will be essential to precisely constrain the underlying metabolic kinetics and refine predictive metabolic models.
Continue reading ‘Biological modulation of shell δ13C in Mytilus galloprovincialis and Phorcus sp.: divergent responses between CO2 vents and laboratory mesocosms’Vulnerability to low salinity but compensatory responses to low pH in an intertidal limpet
Published 7 August 2026 Science ClosedTags: biological response, BRcommunity, laboratory, molecular biology, mollusks, mortality, multiple factors, North Pacific, physiology, salinity
Highlights
- Low salinity linked to warming may intensify coastal pH reduction.
- Low salinity reduced righting and emergence in the limpet Patelloida pygmaea.
- Low salinity reduces Mg/Ca ratios in newly formed shell layers.
- Low pH increases shell thickness and Mg/Ca ratios despite dissolution.
- CHS2 upregulation suggests compensatory resistance to low pH.
Abstract
Rising anthropogenic carbon dioxide emissions have driven ongoing ocean warming and associated climate changes. In the Yellow Sea, this warming is associated with enhanced monsoonal rainfall, which increases freshwater inputs and lowers coastal salinity. Increased freshwater input can weaken seawater buffering capacity, thereby leading to lower pH conditions in coastal environments. Here, we examined the effects of low pH and low salinity on the intertidal limpet Patelloida pygmaea. Adult limpets were exposed for 31 days to four experimental artificial seawater conditions combining two pH levels (8.0 and 7.5) and two salinity levels (30 and 21 psu). Survival and condition factor were not influenced by pH or salinity. However, low salinity reduced righting and emergence behavior. In addition, the Mg/Ca ratio in the M + 1 layer was lower at 21 psu than at 30 psu. Low pH resulted in a thicker M + 2 layer with higher Mg/Ca ratios despite shell dissolution, potentially helping to maintain shell integrity. While there was no change in heat shock protein (HSP70) expression, these shell modifications were accompanied by an upregulation of chitin synthase (CHS2) genes under low pH. These findings suggest that P. pygmaea is negatively influenced by low pH and low salinity, but also demonstrate compensatory mechanisms that enhance resistance to low pH.
The effects of high carbonate alkalinity under low salinity on the survival, physiological metabolism, and redox homeostasis of Crassostrea hongkongensis
Published 28 July 2026 Science ClosedTags: biological response, laboratory, mollusks, mortality, multiple factors, oxygen, performance, physiology, salinity
High carbonate alkalinity can impose composite hydrochemical stress on bivalves by altering inorganic carbon speciation, buffering capacity and ion-exchange conditions. The Hong Kong oyster (Crassostrea hongkongensis) naturally inhabits estuarine areas where low salinity can occur together with carbonate-system disturbance, yet its physiological response to high carbonate alkalinity under a low-salinity background remains unclear. In this study, oysters were exposed at salinity 5 to a Control treatment, A10 (carbonate alkalinity 10 mmol L⁻¹) and A20 (carbonate alkalinity 20 mmol L⁻¹). Salinity was treated as a controlled background condition, whereas the alkalinity treatments represented a composite carbonate-alkalinity perturbation involving alkalinity, pH and carbonate chemistry. Survival, feeding rate, oxygen consumption, ammonia excretion and hemolymph ammonia were measured across Control, A10 and A20. Hemolymph catalase (CAT), glutathione peroxidase (GSH-Px), glucose and ATP were analyzed as A10 and A20 time-course endpoints because a parallel Control was not included for these assays. A 24-h mantle transcriptome was used to screen candidate transcripts associated with innate defense and glutathione metabolism. Oysters under A10 retained partial compensatory capacity, whereas A20 significantly reduced survival. A10 and A20 suppressed early oxygen consumption and ammonia excretion, and altered feeding allocation among microalgae. Within the A10 and A20 biochemical time-course dataset, CAT, GSH-Px, glucose and ATP showed stage-specific variation, suggesting redox and energy-metabolism adjustment under alkalinity stress. Overall, high carbonate alkalinity reduced survival and was associated with metabolic depression, feeding compensation and hemolymph redox-energy remodeling in C. hongkongensis. This study will provide a theoretical basis for water quality regulation in saline-alkaline water aquaculture and the sustainable development of aquaculture.
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