This study assessed the potential synergistic effects of harmful algal blooms (HABs) and ocean acidification (OA) on the survival and grazing potential on HABs by brine shrimp (Artemia salina). The effects on the fitness of three life stages (i.e. newly hatched, 1-week old, and 2-week old post hatch) of A. salina was evaluated over a 24-hour period. Using well plates, A. salina were individually exposed to toxin producing HABs (i.e. Alexandrium catenella or Margalefidinium polykrikoides), a non-toxin producing HAB (i.e. Gymnodinium aureolum), and fed or unfed non-HAB controls. pH conditions administered were ambient (pH ~ 8) or acidified (pH ~ 7.2). Survival analysis revealed a significant effect of treatment on mortality across life stages. Hazard ratios showed elevated mortality in HAB treatments relative to controls, while OA alone did not. HAB exposure or ontogeny are more important for survival of A. salina than short-term OA exposure. Regarding grazing potential, significant reductions in HAB cell density were more commonly found in treatments with older individuals than younger conspecifics. Cell density of A. catenella was never significantly reduced as compared with other HAB treatments. Overall, exposure to OA conditions did not affect the survival or grazing potential of A. salina, but the species of HAB did.
Continue reading ‘Evaluating the combined effects of ocean acidification and harmful algal blooms on the fitness of Artemia salina’Evaluating the combined effects of ocean acidification and harmful algal blooms on the fitness of Artemia salina
Published 6 July 2026 Science Leave a CommentTags: biological response, crustaceans, mortality, multiple factors, performance, physiology, reproduction, toxicants, zooplankton
Reassessing the climate mitigation benefits and environmental risks of coastal seaweed farming
Published 6 July 2026 Science Leave a CommentTags: algae, mitigation, socio-economy
Seaweed farming is increasingly promoted as a nature-based solution for marine carbon dioxide removal (mCDR), offering the dual promise of climate mitigation and ecosystem enhancement. However, here we highlight a fundamental paradox: while macroalgae cultivation can significantly boost carbon sequestration and support biodiversity, it also introduces site-specific ecological risks—most notably eutrophication, hypoxia, and acidification—particularly in semi-enclosed coastal systems with limited water exchange. We synthesize current understanding of both the positive and negative impacts of large-scale macroalgae farming, examining pathways of carbon uptake, storage, and export alongside biogeochemical and food web disruptions. Critically, we identify the overlooked roles of hydrodynamic conditions and benthic-pelagic coupling in mediating ecological outcomes. To ensure that macroalgae aquaculture contributes effectively to climate goals while safeguarding coastal ecosystem resilience, we call for the development of a targeted and comprehensive evaluation framework capable of accurately assessing its impacts on adjacent waters. Such a framework should incorporate site-specific water-exchange characteristics and biogeochemical vulnerability, thereby enabling more informed and adaptive management strategies—including hydrodynamically guided site zoning—to support sustainable, long-term ecosystem benefits.
Continue reading ‘Reassessing the climate mitigation benefits and environmental risks of coastal seaweed farming’Interactive effects of triclosan, microplastic vectors, and ocean warming–acidification on sea urchin embryo development
Published 6 July 2026 Science Leave a CommentTags: biological response, echinoderms, growth, laboratory, morphology, multiple factors, North Atlantic, physiology, plastics, reproduction, toxicants
Highlights
- Microplastics modulate triclosan toxicity in a concentration-dependent manner.
- Microplastic loads reverse triclosan attenuation affecting larval development.
- Acidification amplifies triclosan–microplastic toxicity in sea urchin embryos.
- Ocean Warming modulates toxicity; degree-day normalization reveals hidden stress.
Abstract
Understanding how emerging contaminants interact with climate-driven stressors is essential for accurate ecological risk assessment in coastal ecosystems. This study evaluates the individual and combined effects of triclosan (TC), polyethylene microplastics (MP), ocean warming (OW), and ocean acidification (OA) on the early development of Paracentrotus lividus embryos. A tiered experimental design was implemented to: (i) characterize TC dose–response curves alone and in combination with increasing concentrations of MP (300–3000 particles mL−1), and (ii) assess how OW (24 °C) and OA (pH 7.6) modulate contaminant toxicity. TC showed concentration-dependent growth inhibition, while MP exhibited a biphasic interaction with TC: at moderate concentrations, MP increased EC10 values and steepened dose–response slopes, consistent with contaminant sorption reducing freely dissolved TC. At 3000 particles mL−1, this trend reversed, lowering EC50 values and enhancing toxicity. Morphometric analyses revealed that co-exposure to TC alone and with MP loads impaired arm elongation, increased body-width ratios, and reduced stomach volume, indicating compromised feeding and skeletal development. Climate stressors significantly altered toxicological outcomes. OA strongly amplified the combined toxicity of TC + MP, reducing larval growth to near-zero levels, whereas OW alone did not exacerbate toxicity and partially mitigated OA-driven effects in MP-TC treated groups. Degree-day normalization demonstrated that warming accelerates development but reduces growth efficiency across treatments. Overall, these results reveal threshold-dependent MP–TC interactions and highlight acidification as a critical amplifier of contaminant effects. Incorporating realistic MP–pollutant interactions and climate variables is crucial for improving hazard assessments under future ocean scenarios.
Continue reading ‘Interactive effects of triclosan, microplastic vectors, and ocean warming–acidification on sea urchin embryo development’Study on the mechanical characteristics of the stress relaxation in the carbonate rock after high-temperature acidification
Published 3 July 2026 Science Leave a CommentTags: chemistry, laboratory, modeling, paleo
To elucidate the mechanism by which acidification influences wellbore stability in deep reservoir formations, this study investigates the rheological and mechanical behaviors of the carbonate rock subjected to high-temperature acid etching. A novel experimental system was developed to characterize the stress relaxation behavior of the acid-etched carbonate rock, and the characteristics of the stress relaxation curves under various acid etching conditions and strain levels were systematically analyzed. Combined with Burgers model and the Levenberg–Marquardt algorithm, the evolution of rheological parameters of the carbonate rock under different acid etching regimes was quantitatively evaluated. The results indicate that the acid-etched carbonate rock exhibit significant rheological mechanical properties due to the presence of developed microcracks and complex pore structures. Under the identical acid etching duration and temperature, the initial stress, residual stress, and time required for stress relaxation stabilization all increase with increasing the strain level. Overall, the stress relaxation magnitude prior to the core fracture ranges from 15 to 25 MPa, and the stabilization time for the core stress relaxation falls between 5 and 7 h. The stress relaxation behavior of the acid-etched carbonate core is well described by the Burgers model. At fixed strain levels and temperatures, the instantaneous shear modulus decreases linearly with extended acid etching time, whereas the instantaneous shear modulus and the viscosity coefficients and exhibit exponential degradation. The final variation ranges of the key rheological parameters are determined as follows: instantaneous shear modulus ranges from 5 × 103 to 2 × 104 MPa, instantaneous shear modulus ranges from 6 × 105 to 2 × 106 MPa, viscosity coefficient ranges from 2 × 107 to 8 × 107 MPa h, and viscosity coefficient ranges from 1 × 105 to 1.2 × 106 MPa h. Furthermore, the evolutionary equations correlating the global model fitting parameters with the porosity of acid-etched samples are established, using acid etching time as an intermediate variable. The results of this study provide a theoretical basis for the analysis of wellbore stability after acidification and the selection of acid fracturing completion methods of deep reservoirs.
Continue reading ‘Study on the mechanical characteristics of the stress relaxation in the carbonate rock after high-temperature acidification’Assessing early oil industry awareness of the impacts of fossil fuels on coral reefs using a novel AI agent
Published 3 July 2026 Science Leave a CommentTags: biological response, corals, modeling, review
Global warming threatens to eradicate Earth’s tropical corals. As legal interventions addressing climate change expand, fossil fuel companies’ historical awareness of their products’ damaging effects is increasingly important. We searched historical documents using a large-language-model-based agent, finding that carbon majors were aware by the 1980s of prospective impacts of fossil fuels on corals from ocean acidification, marine heatwaves, sea-level rise, and intensified storms and later funded efforts downplaying such impacts.
Introduction
The world’s tropical coral reefs are under imminent threat of collapse from global warming. Living corals have declined by approximately 50% worldwide since the 1990s, with global warming now the greatest threat to future survival1. Global warming kills corals primarily through increased ocean temperatures and more frequent and intense marine heatwaves, which cause coral bleaching (loss of coral symbionts), exacerbated by ocean acidification (from increased carbon dioxide levels), which weakens coral health, and intensified storms (from increased sea surface temperatures), which physically destroy coral assemblages, all ultimately caused by fossil fuels1. Approximately one billion people worldwide depend directly on coral reefs for livelihoods, food security, and protection from storms and coastal erosion, and coral reefs provide shelter and nourishment to over 30% of the world’s named marine species2. Economically, coral reefs provide an estimated 10 trillion USD per year in ecosystem services, including tens of billions of dollars per year in coral reef tourism3, and potential efforts to restore reefs lost over the last decade alone have been estimated to cost around 1 trillion USD2. Mass coral bleaching and mortality from marine heatwaves driven by global warming is ongoing4. The Intergovernmental Panel on Climate Change (IPCC) predicts mortality of 70—90% of the world’s reef-building corals at global warming of 1.5 °C and mortality of more than 99% at 2 °C1.
Legal interventions may play a critical role in helping to protect the world’s coral reefs and associated ecosystems (for example, by securing funding for reef monitoring and rehabilitation) and in compensating affected communities for economic losses associated with climate-change-driven coral impacts. In this context, the history of fossil fuel industry awareness of the foreseeable impacts of climate change on coral reefs is highly relevant. Climate lawsuits against governments, fossil fuel producers, and other parties have expanded in number and sophistication over the past decade5 and have recently cited impacts on coral reefs6. Additionally, the 2024 and 2025 advisory opinions from the International Tribunal for the Law of the Sea (ITLOS)7 and the International Court of Justice (ICJ)8 on climate change clarified, respectively, that greenhouse gases are marine pollutants under the United Nations Convention on the Law of the Sea (UNCLOS) and that best efforts to attain the 1.5 °C warming limit of the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement are legally binding on governments under international law, strengthening the basis for legal actions seeking to mitigate global warming and obtain reparations for damages. Research on the fossil fuel industry’s internal knowledge of global warming9, public-facing denial and minimization of the problem10,11, and false assurances to be solving it12 has clarified global warming as not only a scientific and technological problem but also one of corporate corruption subject to legal correction and remedy13. Such research has so far informed dozens of ongoing legal actions seeking industry accountability for climate change14.
Continue reading ‘Assessing early oil industry awareness of the impacts of fossil fuels on coral reefs using a novel AI agent’Thermal regulation of benthic fluxes in temperate estuaries
Published 2 July 2026 Science Leave a CommentTags: biogeochemistry, laboratory, multiple factors, sediment, temperature
The effects of short-term heatwave extremes on biogeochemical cycling and fluxes in a temperate estuary of a semi-dry climate were studied using an experimental setup of temperature-controlled benthic incubations. The results demonstrated a strong thermal effect, notably under extreme warming events, for shifts in exchanges across the sediment-water interface. Extreme heatwave conditions (+5 °C of the seasonal mean) boosted acidification, hypoxia, and ammonification, due to accelerated remineralization rates, resulting in strong effluxes of NH4, Si(OH)4, and PO4 to the overlying water. These excessive nutrient loads may increase eutrophication risk via runoff or tidal action, specifically in adjacent oligotrophic coastal waters. CO2 production rates reached ~4000 µatm under extreme hypoxia and acidification, 2.3-fold higher than the ambient rate, with a maximal flux of ~27.0 mmol m-2 d-1. Hence, our experiments show that marine heatwaves amplify CO2 emissions while reducing the CO2 buffering capacity of temperate estuaries. It emphasizes temperate estuaries as highly sensitive ecosystems to climate change.
Continue reading ‘Thermal regulation of benthic fluxes in temperate estuaries’Entering the era of directly supporting society with observation-based ocean acidification data
Published 2 July 2026 Science Leave a CommentTags: chemistry, methods
Ocean acidification is a growing concern for many nations around the world. However, our capacity to monitor changes in carbonate chemistry with sufficient spatial and temporal resolution, has until now, been limited, which has impeded effective action and decision-making at international, national, and regional levels. Recent advancements in machine learning have enabled the integration of Earth observation data with in situ measurements, enhancing data coverage and improving our ability to monitor ocean acidification globally. Here, we highlight how space agencies, particularly the European Space Agency, have supported the development of such products and explore their utility for a broad spectrum of end users, ranging from scientists to resource managers to policy makers and the general public. Spatial and temporal resolution of these products is now on the order of 0.25 × 0.25° and 8-daily, respectively; with similar or slightly enhanced accuracy compared to other methods (e.g., fCO2 in open and coastal ocean are 13 and 25 μatm, respectively). We provide five use cases that demonstrate how the data can be used to: (a) communicate ocean acidification; (b) aid marine planning activities; (c) set up national monitoring and understand baseline conditions; (d) assess impacts of aquaculture; and (e) assess impacts to coral habitats. While these developments represent significant progress, further efforts will enhance the efficacy of observational-data in coastal waters, and could develop complementary biological or water quality indicators. These activities will be accelerated by further building global capacity to ensure equitable access and application of these tools.
Plain Language Summary
Ocean acidification, a change in ocean chemistry caused by the long-term increase in atmospheric carbon dioxide, is a growing global concern. However, it is hard to track these changes accurately across the entire ocean, making it difficult for governments and communities to understand the threat and respond effectively. New advances in machine learning now make it possible to combine satellite data with ocean measurements which have improved our ability to monitor ocean acidification. Here, we highlight how projects funded by the European Space Agency have helped to develop tools that make this information accessible and useful for multiple groups, including scientists, resource managers, policy makers, and the general public. We present five examples for using the data: raising awareness about ocean acidification, supporting marine planning, creating national monitoring systems, understanding the effects on aquaculture like shellfish farming, and evaluating risks to coral reefs. This progress has been long needed, and efforts are beginning to focus on further improving our abilities to observe coastal areas, where conditions can change quickly. Future efforts can now focus on exploring new ways to track changes, and making sure people around the world have the tools and training needed to use these new resources effectively.
Continue reading ‘Entering the era of directly supporting society with observation-based ocean acidification data’Postdoc position: Effects of acidification on marine phytoplankton and zooplankton
Published 2 July 2026 Jobs Leave a Comment- Title: Effects of acidification on marine phytoplankton and zooplankton
- Application deadline: 24-07-2026, 23:59 GMT +2.
- Employment start: 01-10-2026
- Working hours: Full time
- Department/Location: Department of Biology, University of Copenhagen
The project SAFESEA – Safeguarding from acidification: feedbacks and ecosystem services for European and Global action – funded by the EU Horizon offers a 2 year and 2 months post doc position in the effects of acidification on marine plankton organisms. The project is led by Plymouth Marine Laboratories (PML), UK, and involves 11 beneficiaries. The Postdoc will be employed at MBS, located in Helsingør, DK.
Our research
The ocean currently absorbs ~25% of annual anthropogenic carbon dioxide (CO2) emissions. This climate service has delayed atmospheric CO2 concentrations from exceeding 500 ppm, buffering global warming. However, this uptake alters the carbonate system, leading to ocean acidification (OA): CO2 reacts with seawater to form carbonic acid, increasing hydrogen ion concentration, lowering pH, and reducing carbonate ion availability. These shifts in carbonate chemistry have cascading consequences for marine organisms, ecosystems, and human societies. OA is no longer a distant threat; impacts are already evident, from disruptions to shellfish hatcheries to broader marine ecosystem change.
Single drivers physiological performance curves are essential for understanding how marine organisms respond to environmental stressors, particularly in the context of OA and its interactions with other drivers. SAFESEA will identify performance curves, critical tipping points, and/or thresholds where performance is most likely to decline or fail. The focus for the post doc will be on phytoplankton and micro-zooplankton with contrasting physiological traits (calcifying, photosynthetic, mixotrophy, symbiotic and heterotrophic). Performance curves will help to assess the optimal pH range for key traits, which can support improving models in the project, and will provide information on levels at which the susceptibility to other drivers might be enhanced. Experimental results and meta-analyses will be used to develop a theoretical framework that integrates performance curves for key physiological traits to predict marine organism responses to pH and other environmental drivers. By combining models and environmental datasets we will project organismal responses to different scenarios of future conditions and identify critical scenarios for experimental validation in later work. Building on the single-driver work, SAFESEA will evaluate the combined effects of multiple environmental drivers on marine organisms, by designing and conducting multi-driver experiments tailored to the specific sites and species studied in the single driver experiments.
Profile
Applicants should hold a PhD degree in a discipline of relevance for the research project. The position is open to both Danish and international applicants. The main criterion for selection will be the research potential of the applicant. Previous experiences in ocean acidification, multi-stressor context, methodological framework development, and experimental work with marine organisms are preferred. Excellent English language skills will be an advantage.
The supervisor will be Professor Per Juel Hansen. An assessment committee will be appointed to evaluate the applications. The final selection of a successful candidate will be made based on the recommendations of the evaluation committee.
Questions
Further information on the Department is linked at https://www.science.ku.dk/english/about-the-faculty/organisation/. Inquiries about the position can be made to Prof. Per Juel Hansen, Head of Section. Mail: pjhansen@bio.ku.dk, Tel: +4526782117
Foreign applicants may find this link useful: www.ism.ku.dk (International Staff Mobility).
The position is open from 01.10.2026 or as soon as possible thereafter.
The University wishes our staff to reflect on the diversity of society and thus welcomes applications from all qualified candidates regardless of personal background
Terms of employment
The position is covered by the Memorandum on Job Structure for Academic Staff.
Terms of appointment and payment will be according to the agreement between the Ministry of Finance and The Danish Confederation of Professional Associations on Academics in the State.
Negotiation for salary supplement is possible.
Application procedure
The application, in English, must be submitted electronically by clicking APPLY NOW below.
Furthermore, you application must include the following documents – all in PDF format:
- Motivation letter
- Research plan
- Curriculum vitae
- Diplomas (Master and PhD degree or equivalent)
- Complete publication list
- Separate reprints of 3 particularly relevant papers
We reserve the right not to consider material received after the deadline, and not to consider applications that do not live up to the abovementioned requirements.
The further process
After the expiry of the deadline for applications, the authorized recruitment manager selects applicants for assessment on the advice of the hiring committee. All applicants are then immediately notified whether their application has been passed for assessment by an unbiased assessor. Once the assessment work has been completed each applicant has the opportunity to comment on the part of the assessment that relates to the applicant him/herself.
You can read about the recruitment process at https://employment.ku.dk/faculty/recruitment-process/
Interviews are expected to be held in week 33.
Contact
Per Juel Hansen
E-mail: gwz910@ku.dk
Contact
Sam Dupont
E-mail: sam.dupont@bioenv.gu.se
Continue reading ‘Postdoc position: Effects of acidification on marine phytoplankton and zooplankton’Short-term plasticity and long-term transcriptomic rewiring under natural ocean acidification in an ecosystem-relevant sea urchin
Published 1 July 2026 Science Leave a CommentTags: biological response, BRcommunity, echinoderms, laboratory, molecular biology, North Atlantic, vents
Highlights
- Natural CO2 vents reveal transcriptomic responses to chronic ocean acidification.
- Acute low-pH exposure triggers rapid but limited plastic responses in Arbacia lixula.
- Vent-origin Arbacia lixula exhibit extensive metabolic reprogramming and antioxidant activation.
- Low pH supresses biomineralization genes and up-regulates collagen and extracellular matrix pathways.
- Persistence under ocean acidification is associated with energetic trade-offs and skeletal homeostasis.
Abstract
Ocean acidification is reshaping coastal ecosystems as a consequence of anthropogenic CO2 emissions. Natural CO2 vent systems provide valuable analogues for investigating organismal responses to long-term acidified conditions under ecologically realistic scenarios. Here, we examined genome-wide transcriptomic responses of the sea urchin Arbacia lixula, an ecosystem-relevant grazer inhabiting a natural CO2 vent system in La Palma (Canary Islands, Spain). Using RNA sequencing of 24 adults (n = 8 per treatment), we compared: (i) acute experimental exposure of ambient-origin individuals to low pH, (ii) chronic exposure by comparing ambient and vent-origin populations in their native pH conditions, and (iii) a genotype-of-origin comparison under shared low pH. Acute exposure triggered a limited transcriptional response (116 differentially expressed genes, DEG), characterized by activation of ion transport, redox regulation, and NAD-associated metabolism. In contrast, chronically exposed vent-origin urchins showed a tenfold increase in transcriptional changes (1053 DEG), reflecting metabolic reprogramming involving lipid, carbohydrate and amino acid pathways, and strengthened antioxidant capacity. Chronic low-pH exposure was also associated with suppression of biomineralization and developmental genes, alongside strong upregulation of collagen and extracellular matrix–associated genes that may help maintain skeletal performance under reduced carbonate availability. Genotype-of-origin effects (131 DEGs) revealed constitutive differences in metabolic, redox, extracellular matrix, and biomineralization pathways in vent populations. Together, these findings indicate that persistence under natural acidification involves both rapid plastic responses and sustained physiological reorganization, providing mechanistic insight into how calcifying species maintain functional performance under ongoing ocean acidification.
Continue reading ‘Short-term plasticity and long-term transcriptomic rewiring under natural ocean acidification in an ecosystem-relevant sea urchin’Impact of water quality and gear type on Eastern oyster (Crassostrea virginica) growth in Narragansett Bay, RI
Published 1 July 2026 Science Leave a CommentTags: biological response, growth, laboratory, mollusks, mortality, North Atlantic, physiology
Oyster aquaculture is expanding in Rhode Island, yet key farming regions in the lower West Passage of Narragansett Bay (WPNB) lack the in-situ, high-temporal resolution monitoring needed to evaluate emerging stressors and support production. At the same time, the industry is undergoing rapid technological development aimed at improving production while reducing labor and overall costs. In recent years, a low maintenance, alternative surface gear was introduced in WPNB; however, its impact on oyster performance relative to traditional cultivation methods has not been quantified. This study established a 1.5-year continuous water quality time series in WPNB and paired these observations with physiological assessments of Crassostrea virginica grown in three cultivation methods (i.e., traditional surface, alternative surface, and bottom gear). This work aimed to better understand the impact of environmental variability and gear type on oyster health, growth, and survival. Multiparameter sondes and discrete bottle samples were used to monitor water quality and calculate carbonate saturation state (Ω) at a 4-acre oyster farm. Nine mesh bags containing early-life stage C. virginica (16 ± 0.4 mm; n = 300 per bag) were deployed in July 2025, with three replicate bags in each gear type. Subsamples (n = 15) from each gear type were collected over a 6-month period for morphometric measurements and scope for growth (SFG) determinations. Minimal differences in carbonate chemistry were observed among sampling sites and Ω remained supersaturated (Ω >1) for the majority of the study period, indicating that ocean acidification was not a major stressor for farmed oysters. Survival was highest (82 ± 4.5%) in surface gear types compared to bottom gear (27 ± 0.58%), while physical growth (shell and tissue) and SFG were largely similar among all gear types. These results suggest that the alternative surface gear may support comparable production and product quality to traditional gear types, while also reducing maintenance and labor demands. Overall, this study provides important physiological and biological context for oyster aquaculture while informing gear selection and farm management strategies.
Continue reading ‘Impact of water quality and gear type on Eastern oyster (Crassostrea virginica) growth in Narragansett Bay, RI’Aragonite saturation state in the East China Sea during fall 2022: roles of temperature, biology, and mixing
Published 30 June 2026 Science Leave a CommentTags: chemistry, field, North Pacific
This work presents a comprehensive spatial distribution of aragonite saturation state (Ωara) during fall 2022 across the entire shelf of the East China Sea (ECS), a marginal sea of the North Pacific. Our observations revealed pronounced spatial heterogeneity in Ωara. Specifically, surface Ωara was higher in the southeastern ECS in (3.22−3.41), which is influenced by the Taiwan Warm Current and the Kuroshio, than the northern ECS (2.23−2.60), which is affected by the Yellow Sea and the Changjiang River. The lowest Ωara values (1.73−2.20) occurred beneath the mixed layer on the southeastern ECS shelf. Correlation analyses and a one-dimensional diagnostic model identified biological activity and temperature as primary controls on the spatial variability of Ωara. For example, on the southeastern ECS shelf, within the mixed layer, both biological activities and temperature increased Ωara, accounting for ~45% and ~33% of the total absolute contribution of each process. While below the mixed layer, these two processes decreased Ωara, accounting for approximately -38% and -24% of the total absolute contribution. Additionally, water mass mixing substantially influenced Ωara within interaction zones, such as in the intrusion areas of the Yellow Sea and Changjiang River waters. Projections indicate that under future elevated atmospheric carbon dioxide conditions (RCP6.0 and RCP8.5), sea surface Ωara will continue to decline, but the magnitude of decline will be smaller in the northern ECS than in the southeastern ECS, reflecting the carbonate system’s intrinsic buffering effect.
Continue reading ‘Aragonite saturation state in the East China Sea during fall 2022: roles of temperature, biology, and mixing’Erosion-driven delayed warming and marine stress prior to the end-Permian mass extinction
Published 30 June 2026 Science Leave a CommentTags: modeling, paleo, regionalmodeling
The end-Permian mass extinction (EPME) presents an anomaly: intense global warming lags the onset of the carbon isotope excursion (CIE) by ~50,000 years, challenging the presumed link between carbon cycle perturbations and climate warming. Using biogeochemical modeling, Bayesian inversion, and multiple proxies, here we show that incorporating continental erosion as a forcing term into the hyperthermal models can resolve this decoupling. Enhanced erosion, likely resulting from the terrestrial die-off of vegetation, accelerates continental weathering, which buffers early carbon release and delays global warming. This process also increases riverine phosphorus export to the oceans, fostering gradual marine anoxia and preconditioning the oceans for the extinction event. With these findings, we present a coherent unifying scenario for the EPME environmental dynamics. Furthermore, our study refines the hyperthermal paradigm, offering implications for future climate scenarios.
Continue reading ‘Erosion-driven delayed warming and marine stress prior to the end-Permian mass extinction’Climate change and aquatic ecosystems: impacts on salinity, species survival, and ecological resilience
Published 29 June 2026 Science Leave a CommentTags: biological response, fisheries, mesocosms, mortality, phytoplankton, reproduction, review, salinity
Highlights
- Unveils Climate-Driven Disease Mechanisms Across Aquatic Systems.
- Integrates Multistressor Impacts Including Pollution, Eutrophication, and Salinity Fluctuations.
- Explores Shifts in Species Distribution, Reproduction, and Food Web Dynamics.
- Highlights Adaptive Traits and Resilience Mechanisms in Aquatic Organisms.
- Provides Science-Based Recommendations for Climate-Responsive Management.
Abstract
Climate change is rapidly transforming aquatic ecosystems, posing complex environmental challenges with far-reaching ecological and socio-economic implications. Rising temperatures, sea-level rise, altered precipitation patterns, shifting hydrological regimes, and sea-ice loss are intensifying pressures on coastal, estuarine, freshwater, and polar systems. These stressors contribute to habitat degradation, increased frequency of hypoxic events, and altered species distributions. Crucially, while some dual stressors, such as warming and acidification, can paradoxically increase primary producer biomass, our findings reveal that this resultant biomass often accumulates as detritus rather than being efficiently transferred to higher trophic levels. This observation directly challenges the simplistic assumption that “more growth” is invariably beneficial, highlighting complex indirect effects on food web dynamics and ecosystem function. Ecological perturbations propagate through trophic networks, resulting in biodiversity loss, reduced ecosystem resilience, and declining fisheries productivity, thereby threatening food security and coastal livelihoods. Marine and freshwater organisms are increasingly exposed to multiple, interacting stressors, including warming, acidification, salinity fluctuations (requiring distinct osmoregulatory strategies, e.g., heterosmotic regulation in teleosts vs. isosmotic intracellular regulation in crustaceans), pollution, and overexploitation. These cumulative pressures can exacerbate disease outbreaks, modify host–pathogen dynamics, and facilitate the emergence and spread of aquatic pathogens, with consequences for ecosystem stability and human health. In aquaculture systems, climate-driven stress often acts synergistically with anthropogenic disturbances, amplifying production risks and economic vulnerability. Furthermore, anthropogenic infrastructure like reservoirs can act as unintended hubs facilitating species dispersal following extreme events like floods, altering community structures. At the biogeochemical scale, climate-induced alterations in nutrient cycling, primary productivity, and carbon sequestration are reshaping ecosystem functioning, particularly in high-latitude and freshwater environments where adaptive capacity is comparatively constrained. Changes in food web architecture and energy transfer efficiency further compromise ecosystem services. This review specifically centers on the biological and ecological mechanisms underlying these climate-driven changes, including organism-level stress responses, shifts in species interactions, and alterations in pathogen dynamics. Recognizing the societal implications and public discourse surrounding climate change underscores the urgency of examining its tangible impacts on sensitive environments, such as estuarine ecosystems, which serve as critical interfaces between terrestrial and marine realms and are thus highly susceptible to both climatic shifts and human influence.
Continue reading ‘Climate change and aquatic ecosystems: impacts on salinity, species survival, and ecological resilience’Skeletal porosity of a cold-water coral increases with decreasing aragonite saturation state along a depth gradient in the Mediterranean Sea
Published 29 June 2026 Science Leave a CommentTags: biogeochemistry, biological response, BRcommunity, chemistry, corals, laboratory, Mediterranean, physiology
Background
Cold-water corals (CWCs) are key ecosystem engineers that create complex three-dimensional habitats much like tropical reefs, but in deep, cold seas. However, like other reef-building systems, they are increasingly threatened by climate change and ocean acidification. CWC communities in the Mediterranean Sea may be especially vulnerable because these waters absorb more atmospheric CO2 than the global ocean, making it a mesocosm that mirrors broader global trends affecting marine life. Since calcification is energetically costly and likely becomes even more demanding as pH and carbonate ion availability decline, understanding how the decrease in aragonite saturation state (Ωarag) affects biomineralization is essential for predicting the future of these corals.
Results
Here, we investigated skeletal structural and compositional changes of the scleractinian CWC Desmophyllum dianthus along an Ωarag gradient in the Mediterranean Sea using specimens collected between 400 and 1200 m depth. Our findings indicate that skeletal porosity increases at the macro-scale with decreasing Ωarag, while micro- and nano-scale structural and compositional features remained unaffected.
Conclusions
The persistence of micro- and nano-scale skeletal features across an 800 m depth gradient suggests that D. dianthus maintains tight biological control over mineralization at these scales, even as Ωarag declines. This control does not extend to the macro-scale, where increasing porosity alters the skeleton’s overall architecture under lower Ωarag. D. dianthus thus appears to preserve the fundamental “building blocks” of its skeleton while changing its larger-scale structure, a decoupling that may make macro-scale porosity an early marker of acidification stress in CWCs.
Continue reading ‘Skeletal porosity of a cold-water coral increases with decreasing aragonite saturation state along a depth gradient in the Mediterranean Sea’Acute low pH associated with coastal acidification is detrimental to larval development of the Cape urchin Parechinus angulosus
Published 26 June 2026 Science Leave a CommentTags: biological response, BRcommunity, echinoderms, growth, Indian, laboratory, mortality, physiology, reproduction
Acidification in coastal habitats is increasing in duration and amplitude under the continued influence of ocean acidification and contributing coastal processes. The impacts of low pH conditions on calcifying organisms, especially echinoderms, is well established, with the early developmental stages being especially vulnerable. This is the first study to assess the impact of locally relevant coastal acidification scenarios on the early development of the Cape urchin Parechinus angulosus. Our findings suggest that the early larval stages of this species are unlikely to survive when exposed to low pH conditions, specifically during the onset of skeletogenesis. In our laboratory experiments, larvae that were exposed to the low pH treatment (pH 7.32) showed significantly reduced growth (GLMM, Time × Treatment interaction: β = −0.361 ± 0.019, z = −19.06, p < 0.001) and developmental regression compared with those from the control treatment (pH 7.95). Substantially slower growth rates were observed in the low pH treatment (length = 72.3 hpf0.18) compared with in the control treatment (length = 24.24 hpf0.54). There was also evidence of abnormal and delayed development and potential dissolution of skeletal structures under the low pH condition. However, fertilisation success and larval survival did not differ significantly between the experimental treatments, suggesting that developmental impacts of low pH over short durations, even though substantial, may be sublethal. The developmental impacts are likely to impair the transition of larvae to the adult stages, which may ultimately affect populations of this ecologically important species under future coastal acidification scenarios.
Continue reading ‘Acute low pH associated with coastal acidification is detrimental to larval development of the Cape urchin Parechinus angulosus’The Xiamen Symposium on Marine Environmental Sciences (XMAS 2027)
Published 26 June 2026 Events , Science Leave a Comment
The Xiamen Symposium on Marine Environmental Sciences (XMAS 2027) will be held from January 12 to 15, 2027, in Xiamen, China. Please note that the dates have been adjusted to accommodate the schedule of the C&D Xiamen Marathon 2027.
It is organized by the State Key Laboratory of Marine Environmental Science (MEL), Xiamen University, and the Department of Earth Sciences, National Natural Science Foundation of China (NSFC).
Important Dates
Background
To promote interdisciplinary studies in marine environmental science and to foster the next generation of ocean scientists, the State Key Laboratory of Marine Environmental Science (MEL), Xiamen University, initiated the Xiamen Symposium on Marine Environmental Sciences (XMAS) in 2014. The symposium has since grown into one of the largest international conferences in marine sciences in Asia, providing an important platform for the exchange of research advances and scientific ideas related to global and regional oceans.
XMAS 2027 will be held in Xiamen, China, from January 12 to 15, 2027, and is jointly organized by the State Key Laboratory of Marine Environmental Science (MEL), Xiamen University, and the Department of Earth Sciences, National Natural Science Foundation of China (NSFC). XMAS 2027 will feature interdisciplinary, cutting-edge sessions covering physical, chemical, and biological oceanography, marine pollution, as well as marine policy and management. In addition, a range of workshops and special sessions focusing on emerging topics in marine environmental sciences will be offered, including ocean-based carbon removal, ocean governance and sustainability, the marine economy, marine education and outreach, as well as dedicated sessions on Women in Science and mentoring future scientists. These activities will bring together leading experts and early-career researchers from around the world.
Established in 2005 under the sponsorship of the Ministry of Science and Technology of China (MOST), the State Key Laboratory of Marine Environmental Science (MEL) has been awarded the title of Excellent State Key Laboratory in two consecutive official reviews by MOST. MEL is committed to interdisciplinary, cutting-edge research in marine environmental sciences, with particular strengths in marine biogeochemistry and ecosystem studies.
Originally known as Amoy, Xiamen is a coastal city renowned for its rich cultural heritage, pleasant climate, and beautiful natural scenery. Located on the southeast coast of China, Xiamen has a long history of international exchange and maritime commerce. The city has received the United Nations Habitat Scroll of Honor Award and has been recognized as an International Garden City and a National Model City for Environmental Protection. Its clean and well-maintained environment, courteous citizens, and harmonious blend of natural and urban landscapes contribute to a calm, livable, and welcoming atmosphere. Xiamen has a monsoonal humid subtropical climate, characterized by mild and relatively dry winters, with an average temperature of around 15 °C (59 °F) in January.
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The 6ᵗʰ International Symposium on the Ocean in a High-CO₂ World
Published 25 June 2026 Events , Science Leave a CommentMā te kōrero, kia mārama. Mā te mārama, kia mahi tahi,
Mā te mahi tahi, kia mōhio.
The 6ᵗʰ International Symposium on the Ocean in a High-CO₂ World
Moving from Understanding to Action using Multiple Knowledge Systems
Wellington, New Zealand
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Full Programme Now Available – Plan Your Symposium Experience
We’re pleased to share that the detailed provisional programme is now available to view (please note it remains subject to change).
This year’s programme offers a rich and diverse range of sessions, workshops, meetings, and field trips, providing valuable opportunities for learning, collaboration, and connection across the community.
To support planning and maximise access to travel funding opportunities, the early bird and presenter registration deadline has been extended to 1 August.
We also encourage attendees to book early — securing your registration, accommodation, and travel in advance helps keep costs as low as possible.
Your registration includes generous catering throughout the symposium, with morning teas, lunches, and several hosted networking functions, ensuring you are well looked after by the Symposium and our venue, Tākina.
Please note that workshops and field trips have limited capacity and must be selected during registration, so we recommend confirming your place early to avoid missing out.
VIEW THE PROVISIONAL PROGRAMME
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New Workshops
New Workshops
We’re excited to announce two new workshops added to the conference programme:
Engage, Exchange, Collaborate: The mCDR Networking Event Supported by The Ocean Foundation.
A dedicated session to connect researchers and practitioners working in marine carbon dioxide removal, fostering collaboration and knowledge exchange.
Measuring Dissolved CO₂ Across the Ocean Water Column: Technologies, Applications and Emerging Developments Facilitated by -4H-JENA engineering GmbH.
An in-depth exploration of cutting-edge tools and techniques for measuring dissolved CO₂, highlighting practical applications and future directions.
How to sign up:
Workshop places can be selected during the conference registration process.
If you have already registered and would like to add or change a workshop, please contact the conference team at highco2@confer.co.nz.
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Travel and Registration Grants
We’re pleased to share that we’ve launched a Travel and Registration Grants page to support wider participation in the conference.
This includes an exciting new funding opportunity through The Ocean Foundation’s EquiSea Initiative, helping to increase accessibility for attendees from diverse backgrounds.
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Sponsorship & Exhibition Opportunities
Organisations interested in participating as sponsors or exhibitors can request the prospectus below.
REQUEST THE SPONSORSHIP & EXHIBITION PROSPECTUS
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Partner With Us
New Sponsors
We welcome and thank the following organisations for their support:
Foundation Partner
Event Partner – Mātairangi
Hosted By
Supporter – Kaiwharawhara
Sponsors
Korea Ocean Acidification Watch (K-OA Watch)
Published 25 June 2026 Projects , Science , Web sites and blogs Leave a CommentLead institution:
POSTECH (Pohang University of Science and Technology) – Republic of Korea
Korea Ocean Acidification Watch (K-OA Watch) is joint initiative of POSTECH and the Korea Hydrographic and Oceanographic Agency (KHOA) under the OARS Programme.
Centered on the Ieodo Ocean Research Station (northern East China Sea), the project conducts long-term monitoring of ocean acidification in shelf waters.
Weekly sampling targets three core carbonate parameters (pH, TA, DIC), from which additional parameters are derived. This effort will capture long-term trends, seasonal patterns, and short-term variability in acidification, while also quantifying the carbon uptake capacity of shelf seas and identifying its primary drivers.
All quality-controlled data, methods, and code will be openly shared through global repositories, strengthening OARS syntheses and improving regional OA forecasts.
The outcomes will directly inform risk assessment and adaptation strategies for fisheries and coastal communities, contributing to SDG 14.3 by addressing and mitigating OA impacts.
Start Date: 1/1/2026
End Date: 12/31/2030
Lead Contact: Kitack Lee (ktl@postech.ac.kr)
Identification of the source of carbonaceous aerosols using stable carbon and nitrogen isotopes and the implications of its deposition on the coastal ocean
Published 24 June 2026 Science Leave a CommentTags: chemistry, Indian
Highlights
- Aerosols and their major sources are seasonally variable at Visakhapatnam.
- Total suspended matter was higher during winter than during summer.
- Biomass burning is a dominant source of aerosols during winter.
- Fossil fuel and coal combustion are the major sources during summer.
Abstract
The continuous rise in anthropogenic aerosol emissions degrades ambient air quality, and their deposition onto the surface ocean alters chemical and biological characteristics. Identifying the sources of aerosols is crucial for taking appropriate measures to minimize their impacts. Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) are promising tools for identifying sources of carbonaceous aerosols. The objective of this study is to identify the dominant sources of carbonaceous aerosols over an urban region using stable carbon (δ13C) and nitrogen (δ15N) isotope ratios, and to evaluate their potential influence on surface ocean acidification in the coastal Bay of Bengal. Aerosol samples were collected between March 2016 and February 2017 at a fortnightly interval, over an urban region, to examine the sources of carbonaceous aerosols and to evaluate the possible impacts on surface ocean acidification. Significantly high concentrations of total suspended particulates (TSP) during winter (112 ± 26 μg m−3) compared to summer (58.8 ± 8 μg m−3), associated with an insignificant seasonality in δ13CTC (−26.9‰ to −22.9‰), indicating ageing of organic aerosol through oxidation. In contrast, higher δ15NTN during winter (2.2‰ to 12.1‰; 5.4 ± 2.9‰) than summer (−12.9‰ to −1.8‰; −4.7 ± 3.3‰) indicate different sources. Based on source characteristics of δ13CTC, δ15NTN and the isotope mixing model, biomass burning and coal combustion are the major sources of carbonaceous aerosols during winter, whereas coal and fossil fuel burning contributed during summer. Since biomass burning contains higher concentrations of acidic aerosols, such as sulfates, and its deposition over the surface ocean results in higher level of pH levels compared to coal ashes. A higher decline in pH of the coastal waters during winter than summer was reported in the coastal Bay of Bengal. This study confirms that the deposition of higher sulphate and nitrates due to biomass burning in the Indo-Gangetic Plain (IGP) region is responsible for a greater decline in pH of the surface ocean during winter than summer. Taking appropriate measures to reduce biomass burning in the IGP region would decrease ocean acidification and allow the atmospheric CO2 sink into the coastal Bay of Bengal to achieve net zero carbon emissions in the future.
Continue reading ‘Identification of the source of carbonaceous aerosols using stable carbon and nitrogen isotopes and the implications of its deposition on the coastal ocean’
