Temperature and pH-dependent potassium currents of muscles of the stomatogastric nervous system of the crab, Cancer borealis

Published 13 March 2026 Science Leave a Comment
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HIGHLIGHTS

  • Cancer borealis stomach muscles are sensitive to temperature and pH.
  • Warming or alkalizing hyperpolarizes fibers and reduces synaptic response amplitude.
  • qRT-PCR detects K2P gene transcripts CbKCNK1 and CbKCNK2 in muscles.
  • CbKCNK1 and CbKCNK2 are candidates for the temperature and pH-dependent conductances.

SUMMARY

Marine crustaceans such as the crab Cancer borealis experience fluctuations in temperature and pH, yet their stomatogastric neuromuscular system must remain functional for feeding. We examined 16 of ∼40 stomach muscle pairs and found that warming consistently hyperpolarized muscle fibers (∼10 mV per 10°C) and reduced excitatory junctional potentials and currents. Muscle responses were also strongly influenced by extracellular pH, with an optimal range between pH 6.7 and 8.8; outside this window, abnormal activity emerged. Voltage-clamp analysis of gastric muscle gm5b revealed a temperature- and pH-sensitive conductance with a reversal potential near the potassium equilibrium potential and insensitivity to tetraethylammonium and barium, arguing against classical voltage-gated potassium channels. Quantitative RT-PCR detected expression of two putative two-pore domain potassium (K2P) channels in these muscles. Together, these results suggest that muscle excitability in C. borealis is shaped by temperature- and pH-sensitive potassium currents consistent with contributions from K2P channels.

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Environmental controls and nonlinear responses of the diatom-dinoflagellate ratio in Jiaozhou Bay

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Highlights

  • Dia/dino abundance, biomass, and diversity ratios exhibited similar temporal patterns;
  • All ratios showed considerable heterogeneity without a consistent distributional trend;
  • Dia/dino ratios responded distinctly to DO, nutrients, and their interactions;
  • Shifting seawater properties exerted large influence on diatom-dinoflagellate dynamics.

Abstract

Diatoms and dinoflagellates are widely recognized as key indicators of marine ecosystem status and play central roles in ecosystem functioning and biogeochemical cycling. Yet how these two major phytoplankton groups adjust to changing coastal environments, and whether such adjustments occur coherently in different ecological dimensions, remains poorly constrained. Hence, we studied the temporal and spatial dynamics of diatom-dinoflagellate (dia/dino) ratios in Jiaozhou Bay during 2021 and 2024, integrating abundance-, carbon biomass-, diversity-, and richness-based metrics. Although abundance, biomass, and diversity ratios exhibited broadly similar temporal trajectories, the richness ratio displayed an opposite pattern, highlighting a decoupling between numerical dominance and species composition. Spatially, all four ratios exhibited significant heterogeneity, without a consistent nearshore-offshore gradient, reflecting complex local regulation. Correlation analyses revealed distinct controls on dia/dino ratios. The abundance ratio increased under conditions of elevated dissolved inorganic nitrogen (DIN) and reduced dissolved oxygen (DO), whereas the diversity ratio was associated with high DIN and low dissolved inorganic phosphorus (DIP). In contrast, the carbon biomass ratio was primarily linked to reduced DO and lower pH, while the richness ratio responded most strongly to the combined influence of low DO and elevated DIP. These contrasting responses indicated that dia/dino ratios captured different facets of phytoplankton community reorganization rather than reflecting a single environmental driver. Overall, our results suggested that the balance between diatoms and dinoflagellates in Jiaozhou Bay emerged from the coupled and nonlinear interactions among nutrient availability and oxygen dynamics. This study highlighted the dia/dino balance as an integrative indicator of coastal ecosystem condition and implied the importance of considering multiple ecological dimensions when assessing phytoplankton responses to ongoing eutrophication and environmental change.

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A holistic approach to evaluating climate vulnerability of French Polynesia pearl oyster farming: bridging communities and scientific knowledge

Published 13 March 2026 Science Leave a Comment
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Highlights

  • A holistic assessment of climate vulnerability of black pearl aquaculture social-ecological system.
  • Co-definition of adaptation strategies by scientific/institutional actors and local communities of French Polynesia.
  • A list of scientifically robust and locally relevant vulnerability criteria potentially transferable to other Pacific pearl-producing countries.
  • Interviewees consistently identify climate change as a factor that amplifies existing weaknesses in the pearl farming sector.
  • COVID-19 exposed the sector’s dependence on global markets.

Abstract

While there is wide consensus about the reliance of climate projections at global scale, there is still uncertainty about changes at finer scale and even less on the effects of such fluctuations for local economies and societies. The vulnerability of social-ecological systems (SES) to climate change is a framework that takes into account the strong link between environment and local communities that depend on ecosystem services to ensure their livelihoods. This study explores the vulnerability of pearl farming SES to climate change, combining scientific insights with local knowledge from French Polynesian communities. A preliminary list of eighty-two criteria of exposure, sensitivity and adaptive capacity, identified through a targeted scoping review, was used to develop the interview guide that informed fifty-six face-to-face interviews and workshops conducted in 2020 and 2025. Using a combination of ranking questions and open-ended responses, the results highlight differences in the perceived exposure between scientific/institutional actors and local communities, which is reflected in the degree of sensitivity of the SES to climate drivers. Expectedly, the priorities given to adaptation measures were also different. The thematic analysis of the responses, however, shows that the two parties are aware of their own limitations in understanding the effects of climate change and recognise the need to fill mutual gaps through a collaborative production of knowledge. By integrating complementary forms of knowledge, this approach may help overcome the limitations of vulnerability assessments based exclusively on scientific expertise, and support the development of climate policies that are scientifically sound and socially accepted.

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Eco-evolutionary dynamics of planktonic calcifying communities under ocean acidification

Published 12 March 2026 Science Leave a Comment
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Increasing emissions of CO2 into the atmosphere are causing ocean acidification, threatening calcifying organisms. In this study, we model the physiological responses of coccolithophorids to acidification to understand the ecological and evolutionary outcomes of a system in interaction with zooplankton. Assuming a trade-off between growth and protection against grazing, we show that calcification has bivalent effects on transfers between two trophic levels and that acidity can strongly alter energy transfers. Taking into account the evolution of calcifying phenotypes in response to acidification, we show that the system outcome contrasts with previous results. While the effect of evolution depends on how calcification affects grazing, it nevertheless follows that acidification leads to a decrease in calcifying capacity. This evolutionary decrease may be progressive, but can also lead to tipping points where abrupt shifts may occur. Such a counter-selection of calcification in turn affects ecosystem functioning, enhancing energy transfers within the system and modifying carbon fluxes. We discuss how such eco-evolutionary changes may impact food webs integrity, carbon sequestration into the deep ocean and therefore endanger the carbon pump stability.

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Trophic status and climatic stressors in the shallow coral reefs of the Cuban marine shelf

Published 12 March 2026 Science Leave a Comment
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The “Bojeo a Cuba” expedition (summer 2023) provided a synoptic, national-scale snapshot of oceanographic conditions around Cuba’s shallow coral reefs during a regional marine heatwave. At 66 sites across six regions, we evaluated key climatic stressors (sea surface temperature, pH, alkalinity) and trophic status indicators. Satellite-derived SST during each site’s sampling week revealed significantly warmer waters on the southern shelf (mean = 30.93 °C) than the northern shelf (mean = 29.21 °C, P < 0.01). In situ SST was consistently high (mean = 30.52 °C), documenting the heatwave’s intensity. pH (mean = 8.12) and total alkalinity (mean = 2343 µmol kg⁻¹) indicated a currently balanced carbonate system. Concentrations of dissolved inorganic nitrogen and phosphorus were below our methods’ quantification limits (1.61 µmol L⁻¹ for P-PO₄³⁻), while chlorophyll-a (mean = 0.04 µg L⁻¹) consistently classified waters as oligotrophic. This study establishes a critical summer baseline, confirming oligotrophic conditions while documenting the severity of thermal stress during the 2023 heatwave—the most immediate and uniform threat to Cuban reefs. Our findings underscore the vulnerability of these ecosystems to extreme warming events within the context of long-term Caribbean warming trends.

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Effects of long-term exposure to ocean acidification on the Patagonian scallop Zygochlamys patagonica (P.P. king, 1832), a strategic fishery resource in the Southwest Atlantic ocean

Published 12 March 2026 Science Leave a Comment
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Highlights

  • Scallops were resilient to low pH within the present range of natural variability.
  • Negative impacts were observed under true ocean acidification scenario, including:
    • Increased mortality & decreased shell mass condition index
    • Dissolution of the external shell surface modifying shell ornamentation
    • Shell disarticulation leading to the lost ability to swim
  • During depuration time were observed:
    • A recovery of the scallops’ vital functions when the stressor (low pH) was not present
    • No recovery for shell mass condition index, shell ornamentations and disarticulated scallops
    • No new disarticulated scallops

Abstract

Ocean acidification (OA) is a global process leading to a decrease in seawater pH. It is a direct consequence of the increase in CO2 emissions due to human activities with documented impacts on marine species and ecosystems. Effects of a long-term OA exposure (6 months) followed by a 2 months depuration period were evaluated on the Patagonian scallop Zygochlamys patagonica, an important seafood species of the Southwest Atlantic Ocean. Scallops were exposed to three target pHs, (1) pH 7.93, the mean annual pHT at the sampling site, (2) pH 7.83, the minimum value of the natural variability recorded at the sampling site and, (3) pH 7.53, a 0.3 pH unit below the minimum pH. Mortality, shell growth, and shell mass, adductor muscle mass and gonadal mass condition indices were measured at the beginning of the experiment and after 3, 6 and 8 months of exposure. Decreased pH led to a significant increase in mortality and decrease in the shell mass condition index. Shell growth was minimal over the course of the experiment with no effect of pH. The external shell surface showed a gradual dissolution and discolouration over the 6 months exposure to low pH. Shell disarticulation due to ligament damage was also observed in 29% of the animals exposed to low pH after 6 months resulting in loss of swimming ability of scallops, whereas no disarticulated animals were recorded in the high pH treatment. These results show the vulnerability of this species to future OA conditions with implications for the ecosystem services it provides, such as a decline in scallop numbers, greater vulnerability to predation and lower quality of commercial products.

Continue reading ‘Effects of long-term exposure to ocean acidification on the Patagonian scallop Zygochlamys patagonica (P.P. king, 1832), a strategic fishery resource in the Southwest Atlantic ocean’

Ocean acidification at the crossroads I: harmonizing unpurified and purified meta-cresol purple spectrophotometric pHT measurements based on absorbance data

Published 11 March 2026 Science Leave a Comment
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Consistent monitoring of seawater spectrophotometric pH on the total hydrogen ion scale (pHT) has been questioned by an evolving method, with changes in parameterization and the purity of the meta-cresol purple (mCP). Using real seawater samples, we demonstrate that spectrophotometric pHT measurements obtained with unpurified (UNPUR) and purified (PUR) mCP can be harmonized to within 0.003 pH units, the climate-goal threshold. This agreement is only achieved when mCP impurities at 434 nm are quantified for both the UNPUR and PUR mCP, assuming no impurities affect 545 nm absorbances, and impurity-corrected absorbance data at 434 nm are used in the same parameterization to calculate pHT. We applied this approach to a ship-based pHT time series transitioning from UNPUR to PUR mCP measurements. Our results show that previous claims suggesting that UNPUR mCP underestimates pHT in the upper pH range are misleading, as they were based on the inappropriate use of absorbances obtained with UNPUR mCP with a parameterization developed for PUR mCP. In fact, our data reveal better agreement between UNPUR and PUR pHT in the upper pH range of seawater, while UNPUR mCP tends to overestimate pHT in the lower pH range. These findings highlight the urgent need for the global chemical oceanography community to establish a spectrophotometric pHT method with full traceability to the International System of Units (SI), along with affordable and distributed certified reference materials and characterized purified mCP. This work supports the need for harmonization efforts to ensure the reliability of pHT data in global synthesis products.

Continue reading ‘Ocean acidification at the crossroads I: harmonizing unpurified and purified meta-cresol purple spectrophotometric pHT measurements based on absorbance data’

‘Irreversible loss’: how climate change is threatening Europe’s sunken civilisations

Published 11 March 2026 Press releases Leave a Comment
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Climate change is endangering the health of Europe’s oceans, and it’s not just marine life that is affected.

A new study warns that precious underwater cultural heritage is being threatened by ocean acidification.

The research found that materials that make up many archaeological treasures are at risk of deterioration when water pH levels drop.

The research, coordinated by the University of Padua in Italy, examined how ocean acidification, a direct consequence of climate change, can accelerate the decay of submerged archaeological sites.

The scientists studied how quickly historical materials deteriorate through dissolution and biological decay in marine environments, and then integrated these findings with large-scale climate models, lead researcher Luigi Germinario explains.

The results were concerning. While stone degradation was minimal in pre-industrial times and remains relatively limited today, rising emissions could trigger an exponential increase in deterioration rates.

These changes would be “irreversible over the coming decades and centuries, influenced by the materials’ properties and shifting dynamics of biocolonisation” – the growth of microorganisms on the surfaces of submerged structures – Germinario told Italian national newspaper La Repubblica.

The study, published in Communications Earth & Environment, warned that “ocean acidification will pose a severe challenge to protecting underwater cultural heritage, making conservation and adaptation policies more urgent than ever.”

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Multifactorial neural disruption in the brain of the Senegalese sole (Solea senegalensis) under ocean acidification

Published 11 March 2026 Science Leave a Comment
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Global ocean acidification, driven by rising atmospheric CO2, threatens marine ecosystems and biodiversity, with increasing evidence of disruptive effects on fish neurobiology and behaviour. However, the precise mechanisms underlying these impacts remain largely unresolved. Here, we reveal how chronic exposure to future-predicted CO2 levels disrupts brain function in the marine teleost Solea senegalensis. Using an integrative approach combining electrophysiology, immunohistochemistry and transcriptomics, we demonstrate that elevated CO2 induce a complex multifaceted disruption in brain physiology.

Contrary to the prevailing GABAA receptor reversal hypothesis, which predicts Cl− loss and heightened excitatory signalling under high CO2, we observed increased Cl− and HCO3− in cerebrospinal fluid and suppressed neural excitability. Immunohistochemistry revealed reduced expression of glial fibrillary acidic protein across multiple brain regions, suggesting glial impairment. Furthermore, transcriptomic profiling of the olfactory bulb uncovered immune modulation, downregulation of neural excitability genes, and upregulation of neuroplasticity, ciliary, and anti-inflammatory pathways, hallmarks of cellular stress adaptation. Notably, genes involved in circadian regulation and thyroid signalling were also dysregulated, pointing to broader neuroendocrine disruption.

These findings challenge simplistic models of ocean acidification impact, unveiling a cascading interplay of enhanced GABAergic inhibition, immune shifts, glial dysfunction, and disrupted timekeeping mechanisms, likely contributing to the behavioural impairments under high CO2.

Unlike prior studies relying on behavioural assays or direct physiological proxies, our integrative approach, combining direct cerebrospinal fluid ionic measurements, electrophysiology, immunohistochemistry and transcriptomics, unveils a multifactorial physiological cascade. Our work advocated for integrative neurophysiological frameworks to predict marine fish resilience and vulnerability in a rapidly changing ocean.

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Two decades of skeletal density decline in Pocillopora spp. corals in the Mexican Pacific Ocean: insight into a tropical eastern Pacific acidification scenario?

Published 10 March 2026 Science Leave a Comment
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Corals demonstrate vulnerability to environmental changes, exhibiting the capacity to substantially modify coral calcification. In this study, we estimated declines in the density of Pocillopora coral species in the Mexican Pacific. The samples utilized in this study encompass both recently collected corals and those stored in Mexican repositories collected in the northeastern and southern Mexican Pacific regions. Density estimates indicate a 28.6% decline in coral density over the past 23 years (−0.0227 g CaCO3 cm-3 y-1) in the southern Mexican Pacific, while at the entrance to the Gulf of California, density has decreased by 15.4% over the past 20 years (−0.017 g CaCO3 cm-3 y-1). A comprehensive evaluation of environmental data reveals that the observed decline in Pocillopora skeletal density in Mexican Pacific reefs is concomitant with decreases in Ωar and pH, and an increase in ocean temperature on a substantial regional scale. When considered in conjunction with the previously documented reductions in coral growth of Pocillopora spp. skeletons in the eastern Tropical Pacific, our findings indicate a potential decline in CaCO3 production within the region’s reef systems. The results of this study underscore the significance of generating long-term series of coral growth parameters for relevant reef-building species and the carbonate system in key and representative coastal areas, particularly those that are already challenging for coral survival and reef maintenance.

Continue reading ‘Two decades of skeletal density decline in Pocillopora spp. corals in the Mexican Pacific Ocean: insight into a tropical eastern Pacific acidification scenario?’

Consequences of rising atmospheric CO₂ on ocean acidification and dissolved carbon cycling: a systematic review

Published 10 March 2026 Science Leave a Comment
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Increasing atmospheric CO2 and temperature diminish ocean pH and raise the amounts of dissolved inorganic and organic carbons, causing wide-ranging shifts in marine water carbon chemistry and predicting the impacts on long-term ecosystems. This review aimed to determine the ocean chemistry and spatial variation of CO2 at a global scale, as well as to predict the influences of anthropogenic and natural changes on marine ecosystems. The literature has demonstrated that the southern polar oceans, Antarctica, and any coastal zone are predominantly susceptible to marine acidification and the dissolved carbon cycle. Based on 355 studies conducted over the last 30 years, this investigation found that marine acidification and the dissolved cycle are complex and poorly understood phenomena. These two facts and climate change are very interrelated, and the potential of these threats is very spatial, seasonal, stratified, and complex also. It was found that the atmospheric CO2 has increased by about 50% since preindustrial times and excess CO2 raise the seawater acidity through some equilibrium reactions in aqueous medium. The study observed that over the past half-century, the marine surface water acidity has risen by 30%, and predicted that by 2100, it will increase to 150. Moreover, this study critically reviewed the actual rules of marine dissolved organic and inorganic carbon on the global carbon cycle and marine acidification and vice versa. Such a major change in ocean chemistry will already have wide consequences for marine life and ocean ecosystems.

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Sex-specific physiological-biochemical and multi-omics responses of Sargassum thunbergii to ocean acidification

Published 10 March 2026 Science Leave a Comment
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Highlights

  • A multi-omics study on sexual dimorphism of macroalgae under OA.
  • Male S. thunbergii adopted a growth-oriented strategy under OA.
  • Female S. thunbergii showed a defense-oriented survival strategy under OA.
  • Fundamental trade-off between growth and defense underlay sex-specific responses.

Abstract

Ocean acidification (OA), driven by increasing atmospheric CO2 concentrations, poses significant threats to the ecologically important intertidal macroalgae. Multiple previous studies have indicated species-specific responses to OA, the sex-specific physiological-biochemical responses and underlying molecular mechanisms in dioecious macroalgae remain poorly understood. In this study, we investigated the responses of male and female Sargassum thunbergii to acidification treatment (2000 ppm CO2) by integrating physiological-biochemical, transcriptomic, and metabolomic analyses. Both sexes maintained photosynthetic performance, with increased maximum relative electron transport rates (rETRmax). Males exhibited a growth-oriented strategy, characterized by higher accumulation of storage compounds like triglycerides and up-regulation of genes related to the photosynthesis and biosynthesis pathways. In contrast, females displayed a survival-oriented strategy, with reduced carbon storage, increased soluble protein and phenolic substance contents, and up-regulation of genes related to defense- and stress-response pathways. These findings provided physiological-biochemical and molecular evidence for a growth and defense trade-off between male and female S. thunbergii under acidification treatment. Our study provided the mechanistic insights into the sex-specific responses of marine macroalgae to global climate change and highlighted the importance of accounting for sexual dimorphism in predicting the ecological resilience of intertidal macroalgae populations under future ocean conditions.

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The ocean as system

Published 9 March 2026 Web sites and blogs Leave a Comment
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Carbon dioxide released into the atmosphere and absorbed by water lowers its pH level, making the ocean more acidic and less able to sustain life. In 2009 a group of scientists included this ocean acidification (OA) as one of nine planetary boundaries that must remain within safe bounds if the earth is to remain stable and resilient. That study recognised that ocean health is integral to the overall health of the planet. A more recent study concluded that by 2020 the planetary boundary for OA had already been crossed. It is the seventh of the boundaries to have been breached.

For over two decades, governments and international organisations have recognised the danger that OA poses to marine life, and by extension to economies and societies. Supported by a large volume of scientific research detailing the threat, measures to combat OA have been incorporated into numerous national policies and international agreements, including the United Nations Sustainable Development Goals (SDGs). But the crossing of the planetary boundary is a clear indicator that those efforts have failed.

Policy fragmentation, at both international and national levels, is a major reason for the lack of progress on OA. Seen in conflicting objectives, duplication and weak accountability for results, such fragmentation is, an issue across ocean management as a whole. Many experts believe that a more holistic, systems-based approach to ocean management can integrate OA action more effectively alongside parallel efforts to address other stressors of ocean and planetary health. In this article, they discuss why such an approach has potential to eventually turn the tide.

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Acidification stimulates N2O production by oceanic nitrifying bacteria

Published 9 March 2026 Science Leave a Comment
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Recent studies have shown changes in the production rates of nitrous oxide (N2O) in aerobic seawater in response to ocean acidification (OA). Understanding how N2O production responds to OA is crucial because N2O is a strong greenhouse gas and stratospheric ozone‐depleting substance emitted from the ocean. The pH dependence of N2O production rates on marine bacteria Nitrosococcus oceani strain NS58, one of the ammonia oxidizing bacteria that are relevant to nitrification occurring in eutrophic seawater, was investigated under several dissolved oxygen (DO) conditions. We also measured abundance ratios of N2O molecules substituted with rare stable isotopes (isotopocules) to distinguish the two major pathways of N2O production by nitrifiers: NH2OH oxidation and NO2⁻ reduction. The ammonium oxidation rate (VNO2 VNO2) and N2O production rate (VN2O VN2O) calculated respectively from the temporal change of the product concentrations were 4–34 × 10⁻¹⁵ mol h⁻¹ cell⁻¹ and 1–15 × 10⁻¹⁷ mol h⁻¹ cell⁻¹. When compared in the stable phase (t = 44–76 hr), VNO2 VNO2 decreased concomitantly with decreasing DO, also exhibiting a slight increase in acidified water. In contrast, VN2O VN2O was highest at 35% DO (air saturation), showing a 5%–60% increase by acidification (pH 7.7 vs. 8.0) depending on DO. Isotopocule ratios showed an increased contribution from NO2⁻ reduction over NH2OH oxidation under 35% and 3% DO, but its pH dependence was negligible except under 3% DO. These results suggest that OA increases N2O emission in particular from eutrophic seawater and that both N2O production pathways can be stimulated to the same degree.

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IAEA trains early-career scientists to assess the impacts of multiple ocean stressors

Published 9 March 2026 Web sites and blogs Leave a Comment

Winter School lecturer Sam Dupont, from the University of Gothenburg, demonstrates a technique for an experiment on sea urchin fertilization. (Photo: IAEA)

The IAEA is training early-career scientists to assess the impacts of ocean acidification and pollution, helping countries respond to environmental changes.

Marine biodiversity faces growing pressure from environmental changes and pollution. To help countries understand and respond to these combined threats, the IAEA is equipping young scientists with advanced skills to study the ocean’s most pressing challenges.

The Ocean Acidification International Coordination Centre (OA-ICC) trained 14 early-career scientists from around the world in key concepts and cutting-edge techniques to assess the impacts of environmental changes from multiple stressors on the ocean. The third edition of the OA-ICC Winter School on Ocean Acidification and Multiple Stressors was held at the IAEA Marine Environment Laboratories in Monaco from 24 November to 5 December 2025. 

Threats to Ocean Health

The ocean faces multiple pressures, including from acidification, warming and pollution. These stressors threaten biodiversity and food security in many regions. Understanding their combined effects is essential to develop effective mitigation and adaptation strategies. 

“Ocean acidification is not occurring in isolation, but expertise in studying multiple stressors is often lacking. The OA-ICC capacity building programme plays a key role in expanding this knowledge base,” said Lina Hansson, Associate Project Officer at the IAEA.

During the two-week course, participants learned best practices in experimental design and applied them in a hands-on laboratory study. They investigated the combined effects of ocean acidification, warming and lithium pollution on the reproductive success of a common Mediterranean Sea urchin. 

Participants also visited the Laboratoire d’Oceanographie de Villefranche (LOV) in France for practical training in seawater chemistry monitoring and connected with researchers at the Centre Scientifique de Monaco. The Winter School emphasized science communication and community engagement. Through a series of guest lectures, participants explored principles for co-designing research, including integrating traditional knowledge from local communities.

“The Mediterranean Sea is heavily affected by multiple stressors. Record-breaking marine heatwaves, pollution, combined with acidification, have led to mass mortality of key species,” said Steeve Comeau, Research Scientist at LOV and Winter School lecturer. “Training this new generation in multifaceted experimental approaches is critical for predicting future impacts.”

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Introducing the first ocean carbonate chemistry products hub

Published 6 March 2026 Press releases Leave a Comment
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The ocean plays a critical role in stabilizing Earth’s climate. As the planet’s largest active carbon sink, it absorbs about 25% of global carbon dioxide emissions and roughly 90% of the excess heat generated by those emissions. This critical role helps regulate the planet’s climate, but comes at a cost.

“As carbon dioxide enters the ocean, some of it reacts with water to form a weak acid that increases the acidity of the ocean and alters the natural chemical balance of seawater,” said Liqing Jiang, a research scientist at Earth System Science Interdisciplinary Center and NOAA’s National Centers for Environmental Information (NCEI), “As more carbon dioxide enters the ocean, seawater becomes increasingly acidic. In fact, ocean acidity has risen by about 30% since the beginning of the Industrial Revolution.”

A more acidic ocean reduces carbonate ions, which alongside calcium, is a building block for ocean creatures that form skeletons and shells like coral reefs and oysters. Higher acidity reduces coral larval survival, weakens reef structures, and increases ecosystem vulnerability to storms and bleaching. These creatures function as key marine health indicators, and their decline threatens the entire marine ecosystem.

However, the ocean is vast, and the interconnected physical, chemical, and biological processes require scientists like Jiang to integrate many different types of data to piece together the full picture of how ocean chemistry is changing.

To support researchers navigating this complexity, Jiang led a team of international researchers to publish a comprehensive review of over 60 major ocean carbonate chemistry data products. The catalog brings together a wide range of global datasets, including historical time series, model outputs, and aggregated products spanning multiple time periods, making it one of the most comprehensive compilations of ocean carbonate chemistry data products to date.

Jiang’s goal is to present all available ocean carbonate chemistry products. He continues to collect datasets through the catalog to widen the library of data.

“My hope is that researchers will use these products to better understand changes in ocean carbonate chemistry, to improve model inputs for more accurate projections of future ocean conditions, and to support more robust assessments of marine ecosystem vulnerability,” said Jiang.

The paper detailing this work, “Synthesis of data products for ocean carbonate chemistry”, has been published in Earth System Science Data. The full data product catalog is publicly accessible at the following link.

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Glacial meltwater impacts marine carbonate chemistry on Iceland’s continental shelf

Published 6 March 2026 Science Leave a Comment
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Increased meltwater runoff from glaciers may drive localized ocean acidification and impact carbon dioxide (CO2) uptake in the coastal ocean. However, the paucity of carbonate system observations from continental shelves receiving inputs from glaciers limits our understanding of cryosphere‐ocean connectivity. Here, we contrast meltwater impacts on seawater carbonate chemistry and stable isotopes (δ13C‐DIC) off marine‐ and land‐terminating glacier outflows off Iceland. On the shelf outside a marine‐terminating glacier, glacial meltwater reduced the seawater buffer capacity of receiving surface waters through dilution of total alkalinity, and increased CO2 uptake through salinity‐driven drawdown of pCO2. Primary production acted as a counterbalance to the lowered [TA‐DIC]. On the shelf area receiving meltwater from large glacial river deltas, CO2 uptake was almost halved and the saturation state of aragonite was 0.2 units lower than on the marine‐terminating glacier shelf. Reduced net autotrophy due to higher turbidity and upwelling of low‐pH deep waters off the delta‐dominated shelf likely explain those differences. The diverging carbonate dynamics on the two shelves build on previous observations that land‐terminating glaciers can reduce the buffer capacity as well as CO2 uptake potential of nearshore surface waters in comparison to marine‐terminating glaciers. The future retreat of many marine‐terminating glaciers onto land is likely to modify how meltwater will impact coastal seawater carbonate chemistry.

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Applying omics techniques to examine microscopic life fueling Gulf region ecosystems 

Published 6 March 2026 Press releases Leave a Comment
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Scientists at NOAA’s Atlantic Oceanographic & Meteorological Lab and the Northern Gulf Institute applied omics techniques to provide the first basin-scale assessment of the microbial communities at the base of marine ecosystems across the Gulf region. The new study from Dr. Luke Thompson’s group, conducted by Dr. Sean Anderson and co-authors, is the largest environmental DNA (eDNA) or microbiome survey of the Gulf of America ever performed.

Scientists collected environmental DNA (eDNA) – genetic material from whole microbes or shed by marine life into the environment – during the 2021 Gulf and Ocean Monitoring Ecosystems and Carbon Cruise (GOMECC). These samples unlock crucial new insights into the microscopic life across an entire basin – from nearshore coastal ecosystems out to the open Gulf. By analyzing the microbial communities throughout the water column, we can better understand how they are being impacted by changing environmental conditions. 

…

Changes in the composition of these microbial communities in any given region has cascading effects, influencing the biodiversity and feasibility of commercially viable species to survive and flourish in a specific region. Understanding how microbial diversity throughout the water column varies with changing conditions – changes in salinity, temperature, nutrient levels – could unlock key insights and provide early indicators of how entire ecosystems will be impacted by exacerbated environmental stressors, including ocean acidification. 

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Call for abstracts: The Ocean in a High CO2 World Symposium

Published 5 March 2026 Events Leave a Comment

The Call for Abstracts is now open. Please submit your abstract no later than 1 April 2026 (any time zone). Full submission guidelines are provided below.

A limited number of early acceptances are available for applicants with time‑sensitive funding requirements. To request early consideration, please email highco2@confer.co.nz with your abstract submitted through the online form and a brief explanation of why early approval is needed.

Abstracts are invited that align with the themes and special sessions listed below. Details of confirmed special sessions are available here.
During submission, authors should select the theme or special session that best matches their abstract.

SUBMIT YOUR ABSTRACT

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Colony formation sustains the global competitiveness of nitrogen-fixing Trichodesmium under ocean acidification

Published 5 March 2026 Science Leave a Comment
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Anthropogenic carbon dioxide emissions drive ocean acidification. Trichodesmium, a key marine nitrogen-fixing cyanobacterium, displays contrasting growth responses to ocean acidification across morphotypes: negative in filamentous free trichomes but neutral or positive in colonies. However, lacking mechanistic understanding for these discrepancies has impaired our ability to predict Trichodesmium’s ecophysiological response. Here, we develop ecophysiological models to underpin mechanisms behind these divergent responses. For free trichomes, ocean acidification reduces nitrogen-fixing enzyme activity and photosynthetic energy production. In colonies, however, it alleviates copper and ammonia toxicity within the microenvironment—likely synergizing with enhanced iron acquisition—thereby outweighing minor benefit from relieved inorganic carbon limitation in the colony center. Projections suggest that globally, ocean acidification will reduce nitrogen fixation of trichomes by 16 ± 6% but increase that of colonies by 19 ± 24% within this century. By resolving morphotype-specific mechanisms, our study clarifies Trichodesmium’s adaptive strategies for sustaining its competitiveness and biogeochemical impacts in the changing ocean.

Continue reading ‘Colony formation sustains the global competitiveness of nitrogen-fixing Trichodesmium under ocean acidification’

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