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Transgenerational effects of extreme weather on Manila clam resilience: implications for aquaculture sustainability

Published 27 January 2026 Science Leave a Comment
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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.

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Persistence of extreme low pH in a coralline algae habitat

Published 27 January 2026 Science Leave a Comment
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Abstract

The extent of projected ocean acidification is partly dependent on the natural variability of marine carbonate chemistry—which is higher in coastal systems than in the open ocean. However, there are limited empirical studies quantifying the rate, magnitude and drivers of coastal environmental variability, preventing accurate assessments for how species and their associated communities may respond to projected climate change. Here, we quantified the annual variability of pH, temperature and dissolved oxygen in a coralline algae reef, a globally distributed biodiverse habitat that may be one of the most sensitive to projected climate change. We found that coralline algae and their communities are exposed to pH values as low as those projected for 2100 (even under a low emission scenario) for 63% of the year, including most of autumn and all of winter. Annual fluctuations in pH ranged by 0.46 units, with identifiable patterns at diel to seasonal timescales driven by various biogeochemical factors. Biologically driven patterns in dissolved oxygen and pH were coupled at multiple periodicities, and temperature was coupled to pH during the winter. Tidal cycling additionally modulated biological forcing of pH, increasing the complexity of intra-seasonal pH variability. Forecasting this environmental variability to the future led to projections of new pH extremes well beyond all IPCC emission scenarios. However, persistent long-term exposure to low pH may increase the acclimation and adaptation potential of coralline algae and their associated communities, providing a level of optimism for the continued survival of this habitat despite sensitivity to projected climate change.

Plain Language Summary

Here, we studied how the underwater environment naturally changes during the year on a coastal reef made of coralline algae, a type of red seaweed that builds reef habitats and supports diverse marine life. These reefs are thought to be especially vulnerable to climate change, particularly ocean acidification, which lowers the pH of seawater. Unlike the open ocean, coastal areas naturally experience more variability in pH, temperature, and oxygen. Monitoring these throughout the year, we found that the coralline algae reef already experiences pH levels as low as those expected for the year 2100. In fact, for about two-thirds of the year, including all of winter, the reef was exposed to these low pH conditions. We found that pH levels also varied a lot throughout the day and between seasons, influenced by biological activity of the algae and animals living in the reef, the ebb and flow of the tide, and water temperature. With some optimism, since long-term exposure to low pH is already experienced, these algae and their ecosystems may already be somewhat adapted to future conditions. This gives hope that they will be more resilient to future climate change than previously thought.

Key Points

  • Coralline algae are naturally exposed to pH at or below future climate projections, especially during autumn and winter
  • This is driven by an interaction between physical factors (temperature, tidal cycling) and biological processes (community metabolism)
  • Given future climate projections, these pH lows may become more extreme, but prolonged exposure may increase coralline algae resilience
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Climate change and ocean acidification pose a risk to underwater cultural heritage

Published 27 January 2026 Science Leave a Comment
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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.

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Upwelling, growing ocean acidification and deoxygenation (video)

Published 26 January 2026 Presentations , Resources Leave a Comment
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Upwelling, growing ocean acidification and deoxygenation: the future of the northern California Current system

Seasonal upwelling in the Northern California Current System supports abundant plankton, fish, and other marine life, but over the past 30 years has also contributed to growing hypoxia and ocean acidification. In this lecture, CMCC Bassi Fellow Samantha Siedlecki associate professor at the University of Connecticut, whose prominent research is informing coastal resilience strategies and helping communities adapt to changing ocean conditions, will shed light on multi-decadal changes in these stressors and how they are influenced by coastal modification of upwelling, contributing to improved projections of future ecosystem health.

The Northern California Current System (nCCS) is known for its high productivity, supporting diverse fisheries through seasonal upwelling – the rise of cold, nutrient-rich waters from the deep ocean to the surface. However, this process also brings environmental challenges for the continental shelf, including hypoxia (low oxygen) and ocean acidification, conditions that have become more frequent and severe over the past 30 years.

In this CMCC Lecture, Samantha Siedlecki, associate professor at the Department of Marine Sciences, University of Connecticut, and Bassi Fellow at CMCC Foundation, will present new findings on the historical multi-decadal evolution of compound ocean change in the northern California Current system. Dr. Siedlecki’s results highlight that coastal modification of the upwelling signal appears to amplify rates of deoxygenation and acidification in this system, emphasizing that this process is important to monitor and consider in future ecosystem projections.

The Lecture will explore how both seasonal and long-term changes in upwelling influence oxygen levels and acidity on the continental shelf, and how these changes have been captured using the LiveOcean forecast system to simulate ocean conditions from 1993 to 2022, and key metrics such as the Coastal Upwelling Transport Index (CUTI) and the Biological Effective Upwelling Transport Index (BEUTI).

Finally, the talk will highlight the implications of these findings for marine resource management and for projecting the future health of coastal ecosystems.

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An experimental approach to study climate change stress in benthic marine invertebrates

Published 26 January 2026 Science Leave a Comment
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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.

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Core transcriptional plasticity pave the way for fish to succeed in a high-CO2 world

Published 26 January 2026 Science Leave a Comment
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Ocean acidification (OA) can alter the physiological and behavioural traits of marine fishes, raising concerns about how wild species will adapt to rising pCO2. Using natural volcanic CO2 vents at White Island, New Zealand, as analogues for future OA conditions, we quantified behaviours in situ and sequenced the brain transcriptomes of four highly site-attached fish species from two vents and a nearby control site with ambient pCO2, of which two species exhibit increased population densities at the vent. We found that two species showed changes in habitat preferences, and all four species with significant changes in gene expression related to circadian rhythm, visual perception, and energy metabolism at the vents. Strikingly, three differentially expressed genes, a heat shock protein (HS90A) and two immediate early genes (IEGs: JUN and FOS), were central regulators for transcriptional changes across all species at the vents. Within the circadian entrainment pathway, expression changes in opsins may act as a trigger, while core clock genes and IEGs function as downstream effectors, suggesting that elevated pCO2 may reset the circadian clock in these fishes. Notably, the two species with increased populations at the vents exhibited distinct transcriptional responses in genes involved in calcium signalling, reproduction, intracellular pH regulation and energy metabolism. Together with convergent evolution in a calcium signalling gene and an HS90 facilitator, these molecular features may confer their reproduction advantages and ability to cope with elevated pCO2. Our study provides novel insights into the molecular mechanisms underlying fish responses to OA and highlights key pathways that may support survival and ecological success under a naturally high-CO2 world.

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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 Closed
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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 Closed
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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.

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Ocean acidification day of action (video)

Published 23 January 2026 Presentations , Resources Closed
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The Coastal Acidification Networks (CANs) of the Mid-Atlantic, Gulf of America, Southeast and Caribbean hosted a webinar in recognition of the Ocean Acidification Day of Action on Thursday, Jan. 8, 2026. Dr. Aurea Rodríguez Santiago, Founder and Director, Taller Ecológico de Puerto Rico, and Dr. De’Marcus Robinson, Postdoctoral Fellow, Florida A&M University, and the CAN coordinators delivered presentations highlighting their work and the actions they are taking to better understand and address the impacts of ocean acidification (OA). The webinar concluded with a panel discussion and Q&A, creating space for dialogue on research, community engagement and collaborative actions to advance ocean acidification awareness and solutions.

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Editorial: ocean acidification in Latin America

Published 22 January 2026 Science Closed
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Ocean acidification is among the most significant threats to marine ecosystems worldwide, with profound implications for biodiversity, food security, and coastal economies (Gattuso et al., 2023). The Latin American region, with its vast coastline (approximately 59,960 km) and productive marine areas, hosts some of the planet’s most biodiverse ecosystems, including those in the Humboldt Current, the Tropical West Atlantic, the Pacific Central-American Coastal regions, the Gulf of California and the Southwest Atlantic. These ecosystems are critical to livelihoods and climate regulation, supporting diverse habitats such as coral reefs, mangroves, salt marshes, sandy beaches and kelp forests. However, they face significant threats from pollution, degradation, and are particularly vulnerable to changes in ocean chemistry. The studies compiled in this Research Topic of Frontiers in Marine Science provide crucial, up-to-date evidence on the complex interactions between global climate forcings and intricate local oceanographic variability, as well as their impacts on economically and ecologically important species, providing a detailed, multidimensional picture of the region’s specific vulnerabilities and resilience mechanisms. This editorial summarizes the 11 studies in this Research Topic, highlighting the advances in understanding OA in Latin America.

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Detecting the acidity of the ocean with sound, the role of lead in human evolution, and how the universe ends (podcast)

Published 22 January 2026 Media coverage Closed
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First up on the podcast, increased carbon dioxide emissions sink more acidity into the ocean, but checking pH all over the world, up and down the water column, is incredibly challenging. Staff Writer Paul Voosen joins host Sarah Crespi to discuss a technique that takes advantage of how sound moves through the water to detect ocean acidification.

…

This week’s episode was produced with help from Podigy.

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Coastal eutrophication and freshwater inputs drive acidification in the Indian River Lagoon, Florida

Published 22 January 2026 Science Closed
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Highlights

  • First quantification of acidification throughout the IRL using Ωarag.
  • A positive relationship was found between Ωarag and salinity.
  • Ωarag had a negative relationship with dissolved nutrients.
  • Nutrients, algal blooms, and freshwater are drivers of acidification in the IRL.
  • Ωarag is important to understand eutrophication in estuaries.

Abstract

The additive effects of eutrophication and acidification in coastal environments have a wide range of implications for the health of organisms and ecosystems. In the eutrophic waters of the Indian River Lagoon (IRL), FL, USA, decreases in overall shellfish size have been reported, which may be related to coastal acidification. To better understand the relationship between acidification and eutrophication in the IRL, environmental parameters, dissolved nutrients, and aragonite saturation state (Ωarag) were monitored along the entire IRL in the 2016–2017 wet and dry seasons. Additionally, three sites in the central IRL were sampled approximately weekly from June 2016–June 2017 to observe temporal variability. For the IRL-wide survey, northern sites with higher dissolved nutrient concentrations had lower Ωarag due to nutrient pollution and harmful algal blooms, while southern sites with lower salinity had lower Ωarag related to freshwater inputs (i.e., discharges and rainfall). In the time series sampling, there was a positive correlation between Ωarag with salinity and negative correlations with dissolved nutrient concentrations. This work suggests that freshwater inputs and associated dissolved nutrients and organics have implications for acidification in the IRL, which will be important considerations for restoration efforts in the IRL and beyond.

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New river chemistry insights may boost coastal ocean modeling

Published 21 January 2026 Press releases Closed

Rivers deliver freshwater, nutrients, and carbon to Earth’s oceans, influencing the chemistry of coastal seawater worldwide. Notably, a river’s alkalinity and the levels of dissolved inorganic carbon it brings to the sea help to shape regional conditions for marine life, including shellfish and corals. These factors also affect the ability of coastal seawater to absorb carbon dioxide from Earth’s atmosphere—which can have major implications for climate change.

However, the factors influencing river chemistry are complex. Consequently, models for predicting worldwide carbon dynamics typically simplify or only partially account for key effects of river chemistry on coastal seawater. That could now change with new river chemistry insights from Da et al. By more realistically accounting for river inputs, the researchers demonstrate significant corrections to overestimation of the amount of carbon dioxide absorbed by the coastal ocean.

The researchers used real-world data on rivers around the world to analyze how factors such as forest cover, carbonate-containing rock, rainfall, permafrost, and glaciers in a watershed influence river chemistry. In particular, they examined how these factors affect a river’s levels of dissolved inorganic carbon as well as its total alkalinity—the ability of the water to resist changes in pH.

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The internal consistency between calculated and measured variables of the marine carbonate system in Arctic open and coastal waters, case study: Atlantic Arctic

Published 21 January 2026 Science Closed
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Highlights

  • Good consistency between calculated and measured variables of the marine carbonate system in Oceanic waters.
  • Only pH and pCO2 can be calculated with good accuracy in coastal waters.
  • The nutrient data are not required to calculate accurate marine carbonate system data in this region.
  • Total Alkalinity and pH (or pCO2) can be used to obtain good quality pCO2 (or pH) data.

Abstract

The Arctic Ocean plays a crucial role in anthropogenic carbon sequestration, while also being among the regions most susceptible to Ocean Acidification (OA). To understand, quantify, and monitor the rapid biogeochemical changes in the Arctic shelves and coastal waters, it is necessary to accurately determine the complete marine carbonate system. However, the uncertainty range in the calculated values is still unclear, fogging our ability to properly estimate carbon inventory and OA. In this study, we collected samples in the Arctic open and coastal waters to estimate the internal consistency of total alkalinity (TA), pH, partial pressure of CO2 (pCO2) and dissolved inorganic carbon (DIC) when only two of them are measured and the other two calculated. In open ocean waters, calculated values generally show good consistency with observations, whereas in coastal areas, it was only possible to accurately calculate two variables: 1) pH using as input parameters pCO2 together with either TA or DIC, and 2) pCO2 using DIC and pH. Furthermore, we found that, in this dataset, using the TA estimated from its correlation with salinity together with pCO2 also allowed obtaining accurate pH values in both coastal and ocean waters. This opens a new possibility of monitoring changes in the carbon cycle by measuring only salinity and pCO2 in areas where its consistency has been evaluated. Finally, in this study, we provide guidelines for obtaining and reporting good-quality carbonate system data in Arctic coastal areas.

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Nonlinear interactions of timing and amplitude biases in modeled Southern Ocean pCO2: the roles of dissolved inorganic carbon, total alkalinity, and sea surface temperature

Published 21 January 2026 Science Closed
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The Southern Ocean is a major sink for atmospheric carbon dioxide and critical to the current and future carbon cycle. This net annual CO2 flux reflects the balance between strong seasonal variability characterized by opposing periods of winter outgassing and summer uptake. Using a simple framework, we evaluate how model biases in both the amplitude and timing of dissolved inorganic carbon (DIC) and total alkalinity (TA) and in the amplitude of sea surface temperature (SST) impact simulated pCO2. We examine seasonal CO2 fluxes and pCO2 south of the Subantarctic Front in 42 Earth System Model and three state estimate simulations. Only 11 of the 45 simulations have a seasonal pCO2 cycle with a correlation of ≥0.7 to observed pCO2, while 26 have a correlation of <0. Four of the well-correlated models accurately represent the seasonality of SST, DIC, and TA, while TA biases compensate for DIC or SST biases in the other seven. DIC and SST amplitude biases are related to mixed layer (MLD) biases, with shallow MLDs, especially in the summer, correlated with larger amplitude DIC and SST cycles than observed. The amplitude of seasonal Net Primary Production is correlated to DIC and TA timing. We provide input on the main adjustments needed to correct the simulated pCO2 seasonality in each of the evaluated models. These findings highlight the difficulty and importance of capturing the seasonal processes influencing the carbonate system to correctly model and predict the Southern Ocean carbon sink and its response to a changing climate.

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Chronic exposure to low pH negatively impacts blue mussels (Mytilus edulis) from an intertidal zone

Published 20 January 2026 Science Closed
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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.

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Neurometabolic rewiring in squid (Sepioteuthis lessoniana) optic lobes drives behavioral plasticity and visual integration under environmental acidification

Published 20 January 2026 Science Closed
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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.

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Metrological concepts applied to Total Alkalinity measurements in seawater: reference materials, inter-laboratory comparison and uncertainty budget

Published 20 January 2026 Science Closed
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Total alkalinity (TA) measurements in seawater are crucial for characterizing and monitoring the oceanic carbonate system. While international best practices and guidelines exist, the field still lacks widely available traceable reference materials and a well-established uncertainty budget of the measurement method. In this study, we applied key metrological principles – development of reference materials, inter-laboratory comparison and uncertainty quantification – to TA measurements. We developed two reference materials, including an artificial material with a rigorously characterized reference value and an associated uncertainty budget, being traceable to the International System of units (SI). These materials were tested in an inter-laboratory comparison involving five laboratories and demonstrated the applicability of the reference materials developed for quality control. Additionally, we established an uncertainty budget for the TA measurement method using two metrological approaches. The resulting expanded uncertainty was 5 µmol kg−1 (with a coverage factor k=2) in TA, approaching the 4 µmol kg−1 target set by the Global Ocean Acidification Observing Network for climate monitoring. These findings mark a significant step toward improving the quality and comparability of TA measurements, thereby strengthening long-term ocean carbonate system monitoring.

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Spatial dynamics of aragonite saturation state and blue carbon stocks in seagrass meadows of the Palk Bay, Southeast Coast of India

Published 19 January 2026 Science Closed
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Seagrass meadows are increasingly recognized for their role in mitigating climate change through blue carbon sequestration and their influence on local carbonate chemistry. This study investigates the spatial variability of aragonite saturation state (Ωarag) and assesses the blue carbon storage potential of seagrass meadows along the Palk Bay, Southeast Coast of India. Subsurface water samples were collected across multiple seagrass-dominated stations between May and June 2024. Key seawater carbonate system parameters, including pH, temperature, total alkalinity (TA), and salinity, were measured to calculate Ωarag using CO2SYS software. Sediment cores were analyzed for organic carbon content and bulk density to estimate carbon stock. Results revealed significant spatial variation in Ωarag, influenced by seagrass density, species composition (Cymodocea serrulata and C. rotundata), and hydrodynamic conditions. Stations with dense C. serrulata beds showed elevated Ωarag values, suggesting local amelioration of acidification stress. The mean carbon stock was estimated at 1.97 Mg C/ha−1, with higher values in more mature (> 60% cover) and dense seagrass patches. These findings highlight the dual ecological function of seagrass meadows in enhancing local carbonate saturation and functioning as effective carbon storage systems, underlining their significance in coastal ecosystem-based climate mitigation strategies.

Continue reading ‘Spatial dynamics of aragonite saturation state and blue carbon stocks in seagrass meadows of the Palk Bay, Southeast Coast of India’

Northern shrimp exhibit origin-specific proteomic remodelling under ocean acidification, with limited response to ocean warming

Published 19 January 2026 Science Closed
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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’

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