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’Posts Tagged 'laboratory'
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
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’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’Ocean acidification effects on growth, survival and physiological immunity of farmed Larimichthys crocea
Published 29 January 2026 Science ClosedTags: biological response, fish, fisheries, laboratory, morphology, mortality, North Pacific, physiology
Ocean acidification has become a significant global ecological issue, particularly in coastal regions with intensive aquaculture. Fish farming is a crucial component of global food security, yet research on the impact of acidification on the aquaculture performance of economically important teleosts remains limited. In this study, we reared the fast-growing large yellow croaker (Larimichthys crocea) for 30 days under three different pH conditions: severe acidification (LA, pH 7.4), moderate acidification (MA, pH 7.8), and control (HA, pH 8.1). We comprehensively evaluated growth performance, survival rate, tissue structure, antioxidant enzyme activity, and innate immunity. The results showed that the LA group exhibited suppressed growth (significantly lower than the MA group, p < 0.05), elevated cortisol and T4 levels (p < 0.05), and trends of reduced antioxidant enzyme and innate immune enzyme activities, along with organ-specific pathological changes (vacuolation, structural loosening) in gills, liver, kidneys, and intestines, though most indices showed no significant difference from the HA group. Notably, the MA group showed optimal growth performance, stable physiological and immune responses. In conclusion, while acidification did not markedly affect the survival rate of L. crocea, severe acidification (pH 7.4) induces stress responses and tissue damage. These findings suggest that L. crocea exhibits a certain degree of tolerance to the acidification conditions tested, as several physiological parameters were not significantly affected. However, when considering the overall set of observations, including histological alterations across multiple tissues and changes in plasma and tissue parameters, long-term exposure to severe acidification (pH 7.4) appears to induce tissue damage and stress-related physiological disturbances, indicating potential health risks. This study provides empirical evidence regarding the potential risk posed by projected ocean acidification on L. crocea aquaculture and supports the development of climate change adaptation strategies for coastal mariculture.
Continue reading ‘Ocean acidification effects on growth, survival and physiological immunity of farmed Larimichthys crocea’Transgenerational effects of extreme weather on Manila clam resilience: implications for aquaculture sustainability
Published 27 January 2026 Science ClosedTags: adaptation, biological response, fisheries, laboratory, mollusks, morphology, mortality, multiple factors, North Pacific, otherprocess, physiology, reproduction, respiration, temperature
Highlights
- SAE+MHW synergistically impaired clams during reproduction.
- Progeny exhibited lasting developmental delays and high mortality.
- Long-term physiological dysfunction persisted into later life stages.
- Compound extremes threaten bivalve aquaculture resilience.
Abstract
Extreme environmental events, including sea acidity extremes (SAE) and marine heatwaves (MHW), pose increasing threats to coastal aquaculture species. This study examined the individual and combined effects of SAE and MHW on Manila clams (Ruditapes philippinarum) and their transgenerational impacts. Adults exposed to SAE+MHW showed reduced survival, decreased condition index, lower clearance rate (CR) and assimilation efficiency (AE), elevated ammonia excretion (ER), and negative scope for growth, indicating disrupted energy budgets. Reproductive output and gonadal development were also compromised. Offspring from stressed parents exhibited lower larval survival, stunted shell growth, reduced metamorphic success, smaller settlement size, reduced juvenile (6-month-old) survival rate and disrupted energy homeostasis, revealing persistent transgenerational impacts on development and energy homeostasis. These findings suggest that parental exposure to synergistic SAE+MHW alters energy allocation and may involve epigenetic mechanisms, ultimately impairing offspring fitness. Overall, our study demonstrates that compound extreme events can severely affect metabolic resilience and cross-generational performance in Manila clams, highlighting the need for multigenerational assessments, selective breeding, and aquaculture strategies to enhance climate resilience.
Continue reading ‘Transgenerational effects of extreme weather on Manila clam resilience: implications for aquaculture sustainability’Climate change and ocean acidification pose a risk to underwater cultural heritage
Published 27 January 2026 Science ClosedTags: chemistry, field, laboratory, Mediterranean, socio-economy, vents
Ocean acidification caused by climate change drives a spectrum of ecological impacts on the marine environment, while also posing a lurking threat to the traces of human history lying on seabeds. We present a quantitative assessment of the climate change risk to underwater cultural heritage, focusing on the vulnerability of historical stone materials to shifting ocean pH levels. We monitored the amount and rate of stone surface material loss and textural alteration triggered by natural processes of mineral dissolution and biodeterioration in submarine settings, combining field and laboratory experimentations with climate models. Stone deterioration has been minimal in pre-industrial and present times; however, escalating anthropogenic emissions might lead to an exponential surge in vulnerability, with irreversible decay processes accelerating in the next decades and centuries, constrained by material properties and shifting biofouling dynamics. Ocean acidification will dramatically challenge the protection of underwater cultural heritage, demanding urgent preservation and adaptation policies.
Continue reading ‘Climate change and ocean acidification pose a risk to underwater cultural heritage’An experimental approach to study climate change stress in benthic marine invertebrates
Published 26 January 2026 Science ClosedTags: biological response, laboratory, Mediterranean, methods, mollusks, multiple factors, porifera, temperature
Climate change is altering ocean temperature and chemistry, with ocean warming and acidification posing serious threats to marine biodiversity, particularly for sessile or low-mobility organisms that cannot escape unfavorable conditions. The MACCIMO project investigated the effects of these stressors on the sponge Chondrilla nucula and the gastropod Hexaplex trunculus using an integrative approach that examined molecular, physiological, morphological, and symbiotic responses. By applying a common garden experiment to populations from different Mediterranean regions, the study aimed to distinguish genetic and environmental influences on stress tolerance and assess intraspecific variability. Three experimental scenarios were simulated, including a control treatment and two climate change treatments based on the “high GHG emissions” RCP 8.5 scenario. A semi-enclosed experimental system with precise control of temperature and pH was designed which can be easily replicated to support laboratory studies on the effects of climate change and ocean acidification on small marine invertebrates across multiple biological levels.
Continue reading ‘An experimental approach to study climate change stress in benthic marine invertebrates’Prolonged low pH reprograms carbon and nitrogen metabolism and micronutrient use in Symbiodinium kawagutii and reveals indicators for reef water quality management
Published 23 January 2026 Science ClosedTags: biological response, growth, laboratory, molecular biology, photosynthesis, physiology, phytoplankton
Highlights
- Low- pH stress suppresses S. kawagutii growth by ∼50%
- Enhanced NPQ and reduced chlorophyll indicate increased photoprotection
- Lipid pools increase as proteins and carbohydrates are diverted to fatty acids
- Elevated C:N ratios and Fe/Mn loss reveal nutrient limitation under acid stress
- Multi-omics uncover upregulated CA, antioxidant enzymes, and proton pumps
Abstract
Ocean acidification is a pervasive driver of coastal and reef water-quality change. We investigated how chronic low-pH exposure representative of extreme reef scenarios (pH 7.4-7.5) reshapes the physiology and metabolism of the coral symbiont Symbiodinium kawagutii. Integrating growth assays, photophysiology, ultrastructural imaging, biochemical profiling, transcriptomics, and metabolomics, we show that low pH suppresses growth and redirects resources from biosynthesis to stress mitigation. Non-photochemical quenching increased while chlorophyll content declined, indicating photoprotective energy reallocation. Ultrastructural deterioration coincided with losses of protein and carbohydrate pools, whereas fatty-acid stores expanded, evidencing a shift in carbon storage. Elemental and trace-metal measurements revealed higher cellular C:N and significant Fe/Mn depletion, indicating micronutrient constraints under acid stress. Multi-omics analyses identified coordinated upregulation of carbonic anhydrases, vacuolar H+-ATPases, and antioxidant defenses with downregulation of nitrogen and phosphorus assimilation, forming a plastic network that maintains pH and redox homeostasis at the expense of growth. These cellular trade-offs clarify how symbiont plasticity can buffer acidified conditions while altering the quality and quantity of photosynthate available to hosts. By linking mechanistic responses to potential monitoring indicators, this study provides actionable targets to anticipate and manage acidification impacts on reef water quality and to guide restoration strategies that prioritize acid-tolerant symbiont strains and relief of micronutrient stress.
Continue reading ‘Prolonged low pH reprograms carbon and nitrogen metabolism and micronutrient use in Symbiodinium kawagutii and reveals indicators for reef water quality management’Transcriptomic responses of the marine diatom Phaeodactylum tricornutum to high carbon and low nitrogen stress
Published 23 January 2026 Science ClosedTags: adaptation, biological response, laboratory, molecular biology, multiple factors, nutrients, otherprocess, phytoplankton
Diatoms play a pivotal role in global biogeochemical cycling and marine primary productivity, making them ideal model organisms for understanding how phytoplankton respond to environmental fluctuations associated with global climate change. In natural marine systems, diatoms frequently encounter simultaneous variations in carbon and nitrogen availability, yet most previous studies have examined the effects of these factors in isolation. To elucidate the integrated transcriptional mechanisms underlying diatom acclimation to coupled carbon–nitrogen (C—N) imbalance, we employed RNA sequencing (RNA‐Seq) to characterize the global transcriptional response of the model diatom Phaeodactylum tricornutum to high CO2 (~2000 μatm) and low nitrogen (10% of nitrogen concentration in f/2 medium) under parallel culture conditions. The results revealed both shared and distinct transcriptional responses between the two treatments. Key genes involved in carbon metabolism, such as phosphoglycerate mutase (PGAM_7) and dihydrolipoamide succinyltransferase (PHATRDRAFT_40430), were significantly upregulated, indicating enhanced glycolytic and TCA cycle activity. In contrast, the Calvin‐cycle enzyme fructose‐1,6‐bisphosphatase (FBPC4) was downregulated. Genes associated with nitrogen assimilation‐including nitrate reductase (PHATRDRAFT_54983), nitrite reductases (PHATRDRAFT_13154, PHATRDRAFT_8155), and ferredoxin–nitrite reductase (PHATRDRAFT_27757)‐were strongly induced under both conditions. Pathway enrichment analysis further indicated the activation of lactic acid fermentation and nitrogen salvage pathways, suggesting a metabolic shift toward energy conservation and nutrient recycling. Collectively, these findings provide an overview of the transcriptional adjustments that enable P. tricornutum to maintain C—N homeostasis under high CO2 and low nitrogen stress, offering new insights into diatom metabolic plasticity under changing ocean conditions.
Continue reading ‘Transcriptomic responses of the marine diatom Phaeodactylum tricornutum to high carbon and low nitrogen stress’Chronic exposure to low pH negatively impacts blue mussels (Mytilus edulis) from an intertidal zone
Published 20 January 2026 Science ClosedTags: adaptation, biological response, growth, laboratory, mollusks, mortality, North Atlantic, otherprocess, physiology
In intertidal ecosystems, mussels experience daily fluctuations in pH due to the biological activity, intertidal currents, freshwater inflow and anthropogenic influences. This study aimed to determine whether these short-term fluctuations enable blue mussels (Mytilus edulis) to endure long-term exposure to low pH using biological indicators (mortality rates, oxidative stress and enzyme activities). Mussels were collected from an intertidal zone in the western coast of Morocco and exposed for 6 months to seawater pH ranging from 6.6 to 8.0. Our results showed that mortality rates increased exponentially with decreasing pH, while growth rates declined linearly. At pH 6.6, mortality was observed after approximately 15 days and reached 22% at 6 months. Low pH negatively impacted the function of metabolic enzymes (glyceraldehyde-3-phosphate dehydrogenase and succinate dehydrogenase), and caused oxidative stress (elevated lipid peroxidation and protein oxidation) in the mantle, digestive gland, and whole tissues. Additionally, the activity of antioxidant enzymes catalase and superoxide dismutase increased in response to higher levels of reactive oxygen species at low pH. These findings suggest that, although mussels can inhabit intertidal zones with short-term pH fluctuations, this does not equip them with the ability to deal with chronic exposure to low pH (6.6), significantly impairing their fitness.
Continue reading ‘Chronic exposure to low pH negatively impacts blue mussels (Mytilus edulis) from an intertidal zone’Neurometabolic rewiring in squid (Sepioteuthis lessoniana) optic lobes drives behavioral plasticity and visual integration under environmental acidification
Published 20 January 2026 Science ClosedTags: biological response, laboratory, molecular biology, mollusks, North Pacific, performance, physiology
Ocean acidification’s impacts on marine animal behavior have substantial implications for ecosystem stability. Understanding how key predators respond to acidification is crucial for predicting future ocean food web dynamics, yet the underlying neural mechanisms remain poorly understood. Here, we show that prolonged exposure to projected year 2100 acidification conditions substantially impairs predatory behavior in bigfin reef squid (Sepioteuthis lessoniana), a key invertebrate predator. Chronic acidification exposure reduces expression of acetylcholine receptors in optic lobes and alters systemic HCO₃⁻ levels and metabolic rates. Using custom electroretinogram recordings, we find that while basic visual processing remains intact, behavioral impairments likely stem from changes in downstream neural integration pathways. Transcriptomic expression analysis reveals broad reductions in energy metabolism and synaptic signaling under acute exposure, while chronic exposure induces compensatory upregulation of cellular maintenance pathways. Our findings demonstrate that while squids maintain visual capabilities through adaptive mechanisms, the energy-intensive processes of neural integration and behavioral execution are compromised. These results highlight the complex physiological trade-offs marine predators face under ocean acidification, with implications for understanding future shifts in marine ecosystem structure and function.
Continue reading ‘Neurometabolic rewiring in squid (Sepioteuthis lessoniana) optic lobes drives behavioral plasticity and visual integration under environmental acidification’Northern shrimp exhibit origin-specific proteomic remodelling under ocean acidification, with limited response to ocean warming
Published 19 January 2026 Science ClosedTags: adaptation, biological response, crustaceans, laboratory, multiple factors, North Atlantic, otherprocess, physiology, temperature
Highlights
- Ocean acidification, but not warming, drives proteomic response in Northern Shrimp.
- Shrimp from different origins show distinct molecular responses to ocean acidification.
- St. Lawrence shrimp display the strongest protein changes to ocean acidification.
- Local conditions shape how shrimp cope with global change drivers.
- Conservation plans must consider regional differences in shrimp responses.
Abstract
The Northern shrimp (Pandalus borealis) is an ecologically important species and the target of one of the world’Canas largest shellfish fisheries. Yet, its habitats are rapidly changing due to human-driven climate change, with temperatures projected to increase by ∼4 °C and seawater pH to decline by 0.3 pH units the end of the century. These stressors may cause interactive effects, with responses differing among origins due to local adaptation or long-term acclimatisation. We investigated the impacts of ocean warming and acidification (individually and combined) on the proteome of female P. borealis from four geographic origins. Shrimp proteomes responded to ocean acidification, but not to warming, with marked origin-specific differences. Comparing the most favourable condition (2 °C, pH 7.75) to low pH (7.35) across tested temperatures, we detected 109 differentially abundant proteins (DAPs) in shrimp from the Saint Lawrence Estuary (SLE), six in those from the Northeast Newfoundland Coast (NNC) and Eastern Scotian Shelf (ESS), and three in the Esquiman Channel (EC). SLE shrimp showed widespread downregulation across metabolic, genetic information processing, and signalling pathways, suggesting higher sensitivity to acidification relative to other origins, where responses were muted. These findings highlight intraspecific variation in proteomic responses to ocean acidification in this commercially valuable crustacean. They confirm ocean acidification as a major concern in the context of rapid environmental change and suggest that uniform conservation strategies may be ineffective. Instead, management efforts should account for origin-specific sensitivities, reflecting the complex adaptive landscape shaping the resilience of P. borealis and other exploited marine species.
Continue reading ‘Northern shrimp exhibit origin-specific proteomic remodelling under ocean acidification, with limited response to ocean warming’An indoor mesocosm system for cost-effective simulation of multiple ocean stressors affecting marine organisms
Published 16 January 2026 Science ClosedTags: laboratory, methods, multiple factors, oxygen, temperature
Global climate change is exacerbating multiple ocean stressors, including ocean acidification (OA), ocean warming (OW), and deoxygenation (deOxy), which collectively threaten marine ecosystems and fisheries. Understanding how these stressors interact to shape organismal and ecosystem responses is increasingly critical, yet it remains technically challenging and expensive to simulate them concurrently under controlled indoor conditions. To address this limitation, we developed a closed indoor mesocosm system that enables stable and long-term simulation of these three stressors for biological and aquaculture research. The system maintains consistent levels of CO2, temperature, and dissolved oxygen (DO) over multi-month experiments without automated control units, relying instead on robust initial settings. High-purity CO2 and N2 gases are blended with ambient air in controlled ratios to regulate carbonate chemistry and oxygen levels, while chillers and heaters ensure precise temperature control. Validation experiments demonstrated that the system can (1) increase pCO2 to approximately twice the present-day level with a pH reduction of ~ 0.22 units, (2) elevate temperature by + 3 °C above ambient temperature, and (3) reduce DO by up to 40% relative to ambient concentration, reflecting projected climate scenarios. This simple and versatile mesocosm provides a practical platform for investigating the ecophysiological responses of marine organisms under multi-stressor environments, supporting research on climate adaptation and aquaculture resilience.
Continue reading ‘An indoor mesocosm system for cost-effective simulation of multiple ocean stressors affecting marine organisms’Integrated biochemical profiling, comparative transcriptome and weighted gene co-expression network analysis to explore the response mechanism of global warming and ocean acidification to the stress of Sepia esculenta larvae
Published 16 January 2026 Science ClosedTags: biological response, laboratory, molecular biology, mollusks, multiple factors, North Pacific, physiology, reproduction, temperature
Highlights
- Multi-angle analysis of Sepia esculenta under global warming and ocean acidification.
- Stress enhanced the immune defense and antioxidant defense of S.esculenta.
- The hub genes closely related to stress resistance were identified and screened out.
- Provided a theoretical basis for the breeding of fine varieties and pond culture.
Abstract
The Sepia esculenta has high economic value and nutritional value, and accounts for a high proportion of the catch of cephalopods in China ‘s coastal waters. Global warming and ocean acidification, as major environmental problems currently facing the world, have a serious negative influence on the survival and breeding of S. esculenta. Therefore, in the research, transcriptome sequencing and biochemical quantitative analysis were performed on the larvae of S. esculenta after high temperature, low pH and combined stress at different time points, and the differential expressed genes (DEGs) and response mechanisms were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that these DEGs were mainly involved in a large number of immune-related biological processes and signaling pathways, including Immune response、Phagocytosis、Regulation of DNA-templated transcription and Positive regulation of DNA-templated transcription. Then, we further explored the functional relationship between these DEGs by constructing weighted gene co-expression network and protein-protein interaction networks. We identified ten hub genes including HSP90AA1, ALDH1L1, VPS13A, MAPK8IP1 and KDM6A. These hub genes may play an important role in the face of high temperature, low pH and their combined stress at different times. Our findings not only elucidate the molecular response mechanisms of S. esculenta to environmental stress and delineate the key regulatory pathways underlying its adaptation, but also provide a theoretical foundation for advancing pond cultivation.
Continue reading ‘Integrated biochemical profiling, comparative transcriptome and weighted gene co-expression network analysis to explore the response mechanism of global warming and ocean acidification to the stress of Sepia esculenta larvae’Ocean acidification and anthropogenic carbon in the Eastern Mediterranean Sea and the effects of acidification on marine organisms
Published 15 January 2026 Science ClosedTags: biological response, chemistry, field, fisheries, growth, laboratory, Mediterranean, mollusks, mortality, photosynthesis, physiology, phytoplankton, respiration
Ocean acidification (OA), driven by rising atmospheric carbon dioxide (CO2) levels, is a critical issue affecting our oceans. The Eastern Mediterranean Sea (EMS) remains poorly understood in terms of the carbonate system and the impact of OA, despite its key role in Levantine Intermediate Water (LIW) formation and its peculiar characteristics in buffering capacity and ongoing OA. This study provides the first comprehensive spatial and temporal assessment of carbonate system in the North-Eastern Levantine Basin, in EMS, providing essential reference data for Total Alkalinity (TA), Dissolved Inorganic Carbon (DIC), and Anthropogenic Carbon (CANT). The mean TA of the measurements was 2622.11 μmol/kg, with higher surface values in summer, reflected also in the surface salinity (S) maximum caused by strong evaporation. A clear vertical gradient was observed, with TA decreasing with depth. Hot and dry meteorological conditions contribute to increased S and TA, resulting in seasonal and vertical variations in the water column. The mean DIC of the measurements was 2291.23 μmol/kg. In contrast to the observations for TA, surface DIC values were higher in winter than in summer. The higher DIC values in winter are attributed to thermodynamic equilibrium and vertical mixing in the surface waters. This study has also investigates the presence of CANT, has infiltrated deep layers, with a mean concentration of 52.07 μmol/kg, decreasing significantly throughout the water column. These findings confirms the ongoing influence of human activities on intermediate and deep layers in EMS. To reconstruct past carbonate system dynamics, the relationships of TA and DIC were determined with salinity (S) and temperature (T) data. Long-term data from METU-IMS Erdemli Time Series (ETS) stations, collected monthly for a decade, provided valuable findings into seasonal patterns and temporal shifts in TA, DIC, and pH. The coastal station displayed clear trends in the carbonate system over time, reflecting its sensitivity to local environmental changes. In contrast, the offshore station exhibited minimal variability, indicating greater stability against seasonal and long-term fluctuations. These results highlight the heightened vulnerability of coastal waters to carbonate system changes, while offshore waters remain more stable. Understanding carbonate chemistry and acidification levels is crucial for assessing impacts on marine life. In addition to the characterization of carbonate chemistry, this study also explores OA’s biological impacts on two key organisms of the Mediterranean ecosystem: phytoplankton and mussels. Firstly, effects of elevated CO₂ on phytoplankton, an essential primary producer in aquatic food webs and global biogeochemical cycles are explored. Specifically, the study explores the impacts on phytoplankton physiology, focusing on growth rates, respiration, and photopigment content in selected species from the coccolithophores, dinoflagellates, and diatoms groups. While growth rates and respiration remained relatively stable under reduced pH conditions, photopigment content was significantly influenced by changes in seawater pH, highlighting the importance of considering environmental influences on photopigment composition. The study further investigated the effects of acidification on calcifying organisms through a global program aimed at understanding the long-term effects of acidification on key seafood species and exploring adaptation strategies with a collaborative approach. This study focused on the long-term (6 months long experiment) physiological impacts of OA on marine calcifiers, specifically Mediterranean mussel, Mytilus galloprovincialis, an abundant species and one of the most consumed non-fish marine species in Türkiye. Results indicate that OA poses a substantial threat to mussel health and survival. Reduced pH levels negatively impacted survival rates, while other physiological parameters like clearance rate, condition index, respiration, and the distribution of a radionuclide, 210Po, did not significantly change. However, lipid content and immune response were affected. Oxygen consumption decreased over time, especially at lower pH. This study underscores the potential risks of OA to the fitness of the commercially important mussel species, indicating that future OA may impact both this key seafood species and its associated ecosystems. The established baseline data are crucial for future monitoring and provide valuable insights into the vulnerability of marine organisms and ecosystems to ongoing OA. By integrating chemical, biological, and ecological perspectives, this dissertation offers a comprehensive assessment of OA in EMS. It establishes baseline data for carbonate system variables, revealing distinct spatial and temporal variations influenced by S, T, and mixing processes. By linking changes in carbonate chemistry to physiological responses in primary producers and a commercially vital shellfish species, this study highlights the ecological and economic impacts of OA in EMS. The findings emphasize the need for continued research and mitigation efforts to protect marine ecosystems and commercially important species. This integrated approach provides valuable insights into the vulnerability of marine organisms and ecosystems to ongoing OA, underscoring the significance of this research for the Mediterranean Sea.
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