Ocean acidification and warming will alter phytoplankton biomass and composition, yet despite numerous studies, there are few consistent responses on which to base predictions. To determine the responses of chlorophyll-a and phytoplankton size and composition to predicted lower pH (−0.33 to −0.5) alone, and also combined with elevated temperature (+2.5–3.5 °C), two mesocosm experiments were carried out in austral spring and autumn in temperate New Zealand coastal waters. Lower pH alone had no effect on chlorophyll-a in either experiment and, as the treatment pH was lower than the pH minimum recorded in a parallel four-year time series, this lack of response in chlorophyll-a was not attributable to prior in situ exposure. Conversely, chlorophyll-a increased under lower pH and warming in both experiments, with the large (>20 µm) phytoplankton size fraction showing opposing responses under nutrient deplete and replete conditions. Diatom biomass also increased in both treatments when nutrient availability was maintained, with a dominant pennate species Cylindrotheca clostridium emerging. The results highlight the value of contextual time series for experimental interpretation, and also the importance of assessing warming and acidification together using regionally representative nutrient concentrations, for prediction of coastal phytoplankton response to climate change.
Continue reading ‘Coastal phytoplankton response to acidification and warming under differing levels of nutrient availability’Archive for the 'Science' Category
Coastal phytoplankton response to acidification and warming under differing levels of nutrient availability
Published 12 June 2026 Science Leave a CommentTags: biological response, community composition, mesocosms, multiple factors, nutrients, otherprocess, photosynthesis, phytoplankton, South Pacific
High-resolution reconstruction of the pH-upregulation and its seasonal drivers in the temperate coral Cladocora caespitosa
Published 12 June 2026 Science Leave a CommentTags: biological response, chemistry, corals, laboratory, Mediterranean
Ocean acidification (OA) and associated changes in seawater carbonate chemistry, combined with thermal stress, hampers coral calcification. By upregulating pH and dissolved inorganic carbon, corals can optimize their calcification, giving them some resilience to OA. Little is known about the seasonal- and interannual‑scale impacts of thermal stress and OA on pH upregulation and calcification in the temperate coral Cladocora caespitosa, despite it being the only zooxanthellate reef builder in the Mediterranean Sea. δ¹¹B and B/Ca were determined seasonally in C. caespitosa skeletons from two NW Mediterranean sites to reconstruct the effect of seawater temperature and pH on the carbonate chemistry of the coral calcifying fluid (CF), at a bimonthly resolution from June 2013 to August 2017 (Columbretes Islands, Spain), and June 2016 to February 2022 (Villefranche-sur-Mer, France). Cladocora caespitosa displayed a similar pH upregulation strategy to most tropical corals, albeit with an apparently lower sensitivity to seasonal environmental change. Temperature was the main driver of seasonal variability in the CF composition and coral calcification, with seawater pH having a comparatively lower seasonal variability, and acting on longer timescales. While longer coral records and investigations into inter-population variability would still be beneficial in order to fully understand the response of C. caespitosa to environmental change, our records constitute an important first step in understanding the biomineralization strategy of this ecologically important coral species.
Continue reading ‘High-resolution reconstruction of the pH-upregulation and its seasonal drivers in the temperate coral Cladocora caespitosa’Response mechanism of Sepia esculenta larvae under global warming, ocean acidification and salinity fluctuation: Integrated biochemical and transcriptome profiling
Published 12 June 2026 Science Leave a CommentTags: biological response, growth, laboratory, molecular biology, mollusks, North Pacific, physiology, reproduction
Highlights
- Analysis based on global warming, ocean acidification and salinity fluctuation.
- Multi-angle analysis of Sepia esculenta under temperature, pH and salinity stress.
- Different stress enhanced the immune defense and antioxidant defense of S.esculenta.
- The hub genes closely related to stress resistance were identified and screened out.
Abstract
The Sepia esculenta occupies a significant economic proportion in the squid family, and it is also the squid with the largest economic value in the northern sea area of China. With the occurrence of global warming, ocean acidification and ocean salinity fluctuations, it has caused serious negative effects on the development of the S. esculenta artificial breeding industry. Therefore, in the research, we employed weighted gene co-expression network analysis (WGCNA) to investigate the effects of three environmental factors, including salinity, temperature and pH, on the molecular mechanism of S. esculenta larvae, and proved the reliability of transcriptome results through physiological indicators. Enrichment analysis of each module indicated that environmental exposure markedly influenced immune function, oxidative stress responses, and other physiological processes in S. esculenta larvae. Our research elucidates the comprehensive response mechanism of S. esculenta under different environmental stresses, clarifies the significant molecular pathways essential for its growth and development.
Continue reading ‘Response mechanism of Sepia esculenta larvae under global warming, ocean acidification and salinity fluctuation: Integrated biochemical and transcriptome profiling’Ecological roles, climate-driven responses, and critical knowledge gaps of krill in the global ocean
Published 11 June 2026 Science Leave a CommentTags: biological response, crustaceans, fisheries, review
Human-induced global climate change and other anthropogenic stressors are fundamentally altering our oceans. Understanding the ecological and societal implications of these changes is critical for developing mitigation strategies and conservation measures. However, major components of the marine pelagic ecosystem remain poorly understood. This is true for euphausiids (“krill”), which are a crucial part of marine food webs and play an important role in elemental cycling, including in the biological carbon pump, but for which we know surprisingly little. In this review, we first provide an overview of the ecological and socio-economic value of krill, highlighting their function in marine food webs and biogeochemical cycling. Next, we describe what is currently known regarding the response of krill to climate change and other anthropogenic stressors, focusing on changes in their biogeography, physiology, life history, as well as the impacts of krill fishing and their association with pathogens and parasites. We identify five key gaps in our current knowledge of krill: (1) the effects of krill on food web dynamics and stability, (2) the effects of changing predator and/or prey communities on krill populations, (3) the identification of important krill habitats, (4) the understanding of vertical and horizontal range shifts, and (5) the combined effects of multiple climate change and other anthropogenic stressors on krill. We also highlight the krill species, regions, and habitats that are understudied. Finally, we propose strategies to improve our understanding of this ecologically important taxonomic group, including the sustained funding for time series; implementation of novel research technologies; expanding research on understudied species and regions; and creating a global community of krill researchers.
Continue reading ‘Ecological roles, climate-driven responses, and critical knowledge gaps of krill in the global ocean’Climate-induced coastal hazards, impacts and adaptation strategies in Global South countries: a review
Published 11 June 2026 Science Leave a CommentTags: review
Coastal ecosystems provide a wide range of goods and services in the Global South countries. Nevertheless, climate-induced extreme events cause unprecedented impacts that result in a reduction of aquatic goods and services, destruction of infrastructure, and loss of human lives. Hence, effective management and adaptation strategies are required to sustain the benefits of coastal areas and tackle the socioeconomic impacts of climate-induced risks. This review aims to assess the impacts of climate-induced coastal hazards and adaptation strategies in Global South countries. The findings revealed that coastal flooding, cyclones, storm surges, coastal erosion, ocean acidification, algal blooms and saltwater intrusion were the main climate-induced coastal hazards in Global South countries. The South Asian countries face the highest frequency of cyclones and storm surges, while African coastal nations experience greater rainfall variability and drought-related hazards. Besides, ocean acidification disproportionately affect Small Island States. Coastal hazards had significant impacts on the fishery, water, agriculture, coastal ecosystems, and tourism sectors. Saltwater intrusion simultaneously reduces water quality and agricultural productivity, and damages coastal ecosystems. This further creates cascading effects on livelihoods and migration patterns. Studies show that the efficiency of hybrid adaptation measures outweighs the efficiency of hard, soft, and ecosystem-based adaptation measures to adapt to the impacts of coastal hazards in Global South countries. Hybrid approaches achieve 30–45% higher benefit/cost ratios than single-measure adaptations, with lower residual risks and greater ecological co-benefits. In the Global South, development sectors face unprecedented impacts from climate-induced coastal hazards due to their high exposure to coastal hazards coupled with their low economy. The vulnerability of Global South countries to coastal hazards will continue unless all stakeholders act proactively, unlike focusing on reactive adaptation measures. Moreover, an empirical investigation of the economic, social, and environmental impacts of coastal hazards in the region is vital to develop efficient adaptation plans.
Continue reading ‘Climate-induced coastal hazards, impacts and adaptation strategies in Global South countries: a review’Ocean acidification effects on larval development and survival in commercially important shellfish
Published 10 June 2026 Science Leave a CommentTags: biological response, fisheries, growth, mitigation, molecular biology, mollusks, mortality, physiology, reproduction, socio-economy
Ocean acidification effects on larval development and survival in commercially important shellfish
This paper studies the consequences of ocean acidification (OA) on the growth and survival of the larvae of commercially significant shellfish species such as oysters, mussels, and scallops. The authors of the study are particularly concerned with the negative processes of OA with respect to the growth of larvae, shell development, and behavior, which result in decreased survival rates, particularly the consequences of the reduced availability of calcium carbonate on the weakening of shells and larvae, which are preyed upon. The paper also studies the interference with the behavior of larvae, particularly with respect to the adequate detection of sites to settle, which is harmful to recruitment success. Additionally, the study looks at the OA-induced metabolic stress, where the larvae are expected to expend higher energy to maintain homeostasis at the expense of growth and immunity. By focusing on this issue, the paper outlines the OA’s impacts on the shellfish populations and industries. The paper also looks at the available soft measures, such as the implementation of buffering solutions to limit the acidification in hatcheries, the use of genetic selection to incorporate acidification-resistant traits, and coastal management measures to limit local sources of acidification. The paper also suggests some potential new ways to increase the resilience of shellfish stock, including more flexible adaptive aquaculture practices. With commercial shellfish interests emerging, this paper fills some of the more critical gaps in the existing literature and offers insight into the impact of OA on the sustainability of the shellfish industry. It also provides OA mitigation strategies to preserve shellfish stocks in a changing climate.
Continue reading ‘Ocean acidification effects on larval development and survival in commercially important shellfish’Dialogue, inclusion, and adaptation in a remote marine sanctuary: evidence from Flower Garden Banks
Published 10 June 2026 Science Leave a CommentTags: modeling, policy, review
Interdisciplinary, stakeholder-engaged research is increasingly being used for managing climate change in social-ecological systems. We apply a Collaborative Adaptive Experimental Governance lens to the Flower Garden Banks National Marine Sanctuary, a remote, relatively pristine coral reef system ~130–190 km offshore in the Gulf of Mexico, where biodiversity protection coexists with recreation and offshore energy. We coupled participatory social science with climate and ecosystem modeling to inform dialogue with decision-makers and users. First, we generated scenarios using Community Earth System Model2-LE ocean temperature and aragonite saturation state to characterize warming and acidification; translated heat stress into a variability-based coral bleaching index; and projected demersal and pelagic fish biomass. We then conducted 37 semi-structured interviews (managers, oil and gas, commercial and recreational fisheries, dive operators, Non-governmental organizations, and science/education), employed multi-coder reliability, and triangulated findings with policy and legal documents. Results highlight the centrality of the Sanctuary Advisory Council in structuring inclusive dialogue, co-producing recommendations, and supporting outreach in distant coastal communities. Multi-level coordination among NOAA, the Gulf of Mexico Fishery Management Council, and the Bureau of Ocean Energy Management enabled boundary expansion and reconciled conservation with industry and fishing interests. Key barriers to adaptive responses include offshore remoteness and logistics, limited public awareness, funding constraints, trust deficits, and procedural delays; pressures that intersect with warming, acidification, and episodic hypoxia. Our study shows that remote marine protected areas can operationalize inclusive, experimental governance to align science and management, but sustained investment in monitoring, restoration capacity, boundary-spanning outreach, and cross-agency coordination is needed.
Continue reading ‘Dialogue, inclusion, and adaptation in a remote marine sanctuary: evidence from Flower Garden Banks’Optimization of UV-Vis spectrophotometer (OCaPI) parameters for measuring the pH and pCO2 of the ocean carbonate system in seawater to assess ocean acidification (Mediterranean Sea)
Published 9 June 2026 Science Leave a CommentTags: chemistry, Mediterranean
Optimization of UV-Vis spectrophotometer (OCaPI) parameters for measuring the pH and pCO2 of the ocean carbonate system in seawater to assess ocean acidification (Mediterranean Sea)
Automating the measurement of carbonate system parameters is essential for improving our understanding of biogeochemical processes in marine regions. The portable OCaPI (Ocean Carbon Parameters Instrument) is designed to perform simultaneous and accurate measurements of hydrogen ion concentration (pH) and partial pressure of carbon dioxide (pCO2)1 in the ocean environment. Optimizing the parameters of the UV-Vis spectrophotometer (integration time, scan-to-average, boxcar) facilitates the quantification of ocean acidification, with significantly improved measurement accuracy and reliability. The results obtained are consistent with existing techniques and offer a simplified approach to data collection, even under challenging conditions. This work, based on design principles, performance, and preliminary results obtained in the Mediterranean Sea, paves the way for the integration of these optimized techniques into long-term monitoring programs. This will contribute to a better understanding of the impacts of climate change on marine ecosystems and to improved management in the face of ocean acidification.
Continue reading ‘Optimization of UV-Vis spectrophotometer (OCaPI) parameters for measuring the pH and pCO2 of the ocean carbonate system in seawater to assess ocean acidification (Mediterranean Sea)’Ocean acidification alters hypoxia sensitivity and oxyregulation in reef-building corals
Published 9 June 2026 Science Leave a CommentTags: biological response, BRcommunity, chemistry, corals, laboratory, North Atlantic, physiology
Coastal marine ecosystems are increasingly threatened by multiple stressors such as ocean acidification and deoxygenation, but how these co-occurring stressors interact is often poorly understood. This is especially true for tropical coral reefs where deoxygenation is an emerging yet understudied threat. Using hypoxia response curves combined with rigorous pH control, we show that acidification alters hypoxia sensitivity and oxyregulation of reef-building corals in a species-specific manner: three species exhibited increased sensitivity to various degrees, while the fourth showed enhanced tolerance. Consequently, acidification pushes critical hypoxia thresholds into oxygen regimes already prevalent on reefs today, potentially driving shifts in community composition and accelerating risks to reef resilience as these stressors intensify in the future. Our findings challenge assumptions of uniform coral vulnerability under multi-faceted climate change, emphasizing the need for trait-based approaches and to account for stressor interactions in predictive models to better anticipate coral reef futures under rapid climate change.
Continue reading ‘Ocean acidification alters hypoxia sensitivity and oxyregulation in reef-building corals’Ocean acidification, more than warming or heatwaves, constrains shoaling behaviour in a range-extending fish through habitat simplification
Published 8 June 2026 Science Leave a CommentTags: biological response, BRcommunity, field, fish, North Pacific, performance
- Social context is a critical yet underexplored determinant of behavioural resilience to climate change. Group living can buffer individuals against environmental stress through enhanced vigilance, reduced predation risk and improved foraging efficiency.
- However, whether these behavioural expressions persist under chronic (warming, acidification) and acute (marine heatwaves) climate stressors remains unclear. Using natural climate analogues spanning present-day, ocean warming and combined warming–acidification reefs, we quantified how shoal size influences behavioural expression in a range-extending reef fish (Pomacentrus coelestis).
- Across all climate conditions, fish in larger shoals consistently exhibited higher foraging and activity levels and reduced risk-avoidance behaviours, whereas direct effects of warming, acidification and heatwaves on behaviour were negligible.
- In contrast, ocean acidification most likely constrained collective behaviour indirectly by simplifying benthic habitats, where fish densities were 84% lower than at the warming reef, resulting in shoals that were up to 79% smaller than the Warming and Control reefs.
- Combined, our data suggest that shoal size mediates behavioural expression between foraging and predator avoidance and that acidification-driven habitat simplification can alter behavioural expression indirectly by reducing fish densities and the formation of large shoals.
- We conclude that climate change can indirectly modify behavioural expression in shoal-forming fishes through habitat-driven erosion of social structure.
Systematic review of chemistry educational strategies and curriculum integration in ocean acidification
Published 8 June 2026 Science Leave a CommentTags: chemistry, education, review
Systematic review of chemistry educational strategies and curriculum integration in ocean acidification
This systematic literature review examines the trends and developments in ocean acidification education research from 2011 to 2025. Using the PRISMA methodology, 30 articles from the Scopus database were analyzed to identify key themes, research gaps, and future directions in teaching and learning about ocean acidification. The findings reveal a growing interest in integrating ocean acidification into science education curricula, with a significant emphasis on inquiry-based learning, technology-enhanced instruction, and interdisciplinary approaches. The United States leads research production (51 authors), followed by Spain, Sweden, and Greece. Key educational innovations include virtual reality applications, computational modelling, hands-on laboratory experiments, and collaborative learning strategies. With an average of 23.37 citations per document, this field has a substantial academic impact. However, challenges persist in terms of public awareness, teacher preparation, and curriculum integration. The review identifies the critical need for enhanced pedagogical resources, professional development programs, and assessment tools to effectively teach ocean acidification as a climate change issue. These findings provide valuable insights for educators, curriculum developers, and policymakers seeking to strengthen ocean and climate change education in formal and informal settings.
Continue reading ‘Systematic review of chemistry educational strategies and curriculum integration in ocean acidification’Assessing recent anthropogenic carbon dioxide and acidification in the Ross Sea, Antarctica
Published 5 June 2026 Science Leave a CommentTags: Antarctic, chemistry, field
Over the past decade, the East Ross Sea has experienced a significant decline in sea ice, enabling direct observational studies of regional carbon dynamics. The accumulation rate of anthropogenic CO2 in the East Ross Sea is up to six times higher than the long-term Industrial Era mean due to the inflow of seawater from the Amundsen Sea by accelerated glacial melting. In contrast, the West Ross Sea exhibited comparatively smaller changes. Measurements of dissolved inorganic carbon and stable carbon isotope indicate that, over the period 2011–2020, changes in δ13C (Suess effect) and anthropogenic CO2 were 0.20 ± 0.06‰ and −5 ± 2 μmol kg−1 in the West Ross Sea, and −0.15 ± 0.01‰ and 9 ± 1 μmol kg−1 in the East Ross Sea. These findings suggest rapid acidification in the East Ross Sea, with aragonite undersaturation likely to occur by the mid-2030s, accompanied by an expected pH decrease of ∼0.2 units by the end of the century.
Continue reading ‘Assessing recent anthropogenic carbon dioxide and acidification in the Ross Sea, Antarctica’Climate change impact on the socioeconomic conditions and well-being of the South Asian small-scale fishermen: a review
Published 5 June 2026 Science Leave a CommentTags: policy, review, socio-economy
Climate change is a major threat to the small-scale fishing communities, particularly in South Asia, a region characterized by widespread coastlines, extreme population density, and high dependence on marine resources for food, income, and employment. This review synthesizes findings from peer-reviewed articles published between 2000 and 2025 to analyse the climate change impact on socioeconomic conditions and well-being of the small-scale fishermen. The review identifies a range of climatic stressors, such as rising sea surface temperatures, ocean acidification, sea level rise, and extreme weather events, that are severely disrupting marine ecosystems and fish availability. These ecological shifts directly affect the livelihoods, income stability, and food security of fishing communities, escalating existing vulnerabilities like poverty, indebtedness, and limited occupational mobility. The study categorizes the impacts into physical, economic, and social dimensions, highlighting issues such as declining catch volumes, increased operational costs, infrastructure destruction, and disruptions in food supply and nutrition. It also examines local and regional adaptation responses, ranging from ecosystem-based solutions, such as mangrove restoration and cage aquaculture, to institutional and behavioural shifts, including migration, livelihood diversification, and early warning systems. While some adaptations enhance resilience, others pose sustainability challenges. This review highlights the pressing need for targeted policy interventions that support sustainable adaptation, enhance institutional frameworks, and prioritize vulnerable fishing communities in climate resilience planning.
Continue reading ‘Climate change impact on the socioeconomic conditions and well-being of the South Asian small-scale fishermen: a review’A screening approach for aquaculture breeders based on sperm performance under climate change-related stress
Published 4 June 2026 Science Leave a CommentTags: biological response, BRcommunity, fish, laboratory, multiple factors, performance, reproduction, temperature
Highlights
- Temperature rise reduced European sea bass and Senegalese sole sperm motility.
- Gilthead seabream sperm showed lower variation under acidification and warming.
- Challenge tests allowed differentiation among males based on sperm performance.
- Approach provides a screening framework for sperm performance.
Abstract
We aimed to develop a screening approach to differentiate among males of European sea bass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and Senegalese sole (Solea senegalensis) based on sperm performance under environmental acidification and temperature increase. Sperm samples were selected using a CASA system, and three challenge tests were applied. The first one consisted of sperm activation with artificial seawater (ASW) across a pH range (7.6–8.2). The second assessed activation at species-specific temperatures. The third test evaluated the combined effect of ASW pH (7.8 and 8.2) and different temperatures. Results from the third challenge test revealed differences in sperm performance under environmental variations, allowing differentiation among males. For this purpose, sperm motility values obtained for each sample under species-specific natural environmental conditions were used as references, and variations in motility were compared across challenge conditions. Different levels in the criteria (regarding the different percentages of motility variation) were applied to differentiate among males. The temperature increase affected the sperm kinetic parameters of European sea bass and Senegalese sole, while gilthead seabream sperm showed lower variation under seawater acidification and rising temperatures. The challenge test allowed differentiation among males based on sperm performance under environmental variations and represents a preliminary screening approach. However, these results are based on in vitro conditions and should be interpreted as a first proxy, requiring further validation to establish links with reproductive performance in vivo.
Continue reading ‘A screening approach for aquaculture breeders based on sperm performance under climate change-related stress’Environmental, phylogenetic, and palaeogeographic impact on relative septal thickness in Devonian ammonoids from Morocco
Published 3 June 2026 Science Leave a CommentTags: biological response, BRcommunity, laboratory, mollusks, paleo, physiology
Building upon previous research, this study examines potential relationships between septal thickness in Devonian ammonoids from the Anti-Atlas of Morocco and isotopic proxy data from the literature for atmospheric CO2, sea surface temperature, oceanic pH, and weathering (δ18O, δ13C, δ11B, 87Sr/86Sr). Recent studies have demonstrated that various mollusc groups show some growth sensitive to environmental factors. Our results indicate no significant correlation between septal thickness and the examined proxies, except for significantly thinner septa in the genus Phoenixites following the environmental perturbations during the Kellwasser Event, which included anoxic conditions and possibly ocean acidification. This supports the hypothesis that a positive selection for reduced shell material occurred in response to changing seawater chemistry. Additionally, our results align with published data and may support a correlation between septal thickness and palaeolatitude. This study contributes to our understanding of the evolutionary impacts of environmental stressors such as ocean acidification on ammonoids and their adaptive strategies to changing environmental conditions.
Continue reading ‘Environmental, phylogenetic, and palaeogeographic impact on relative septal thickness in Devonian ammonoids from Morocco’Seasonal upwelling shapes coral reef community structure and photophysiology on the Pacific Coast of Costa Rica
Published 3 June 2026 Science Leave a CommentTags: algae, biological response, community composition, corals, echinoderms, field, modeling, North Pacific, otherprocess, photosynthesis, physiology, regionalmodeling
Reef-building corals form the calcium-carbonate frameworks that underpin tropical coral reefs, yet global coral cover has declined by ~50% in recent decades, due to marine heatwaves and other stressors. Identifying refugia environments, such as upwelling systems, that buffer stress, promote recovery, and enhance resilience by promoting physiological plasticity that supports thermotolerance is therefore critical. Here, we compared benthic community composition, coral percent cover, and photo-physiology between an upwelling location in the Gulf of Papagayo and a non-upwelling location in Sámara on the Pacific coast of Costa Rica. Waters in Papagayo were cooler, more acidic, and richer in chlorophyll a. Reefs at this location exhibited higher crustose coralline algae, higher sea urchin cover, and lower macroalgae cover, compared to Sámara. Papagayo also showed higher stony coral cover, driven by Pocillopora spp., while Sámara was dominated by massive, heat-tolerant Porites spp.. When significant, photophysiological measurements showed 9.7 – 44.5% higher photosynthetic efficiency (Fv’/Fm’) in Papagayo corals and 19.94 – 42.75 % higher maximum photosynthetic rates (Pmax) in Sámara corals. These results highlight how contrasting environmental regimes within a relatively small geographic area can shape distinct coral community compositions and photophysiological strategies, with implications for identifying areas of reef persistence or refugia.
Continue reading ‘Seasonal upwelling shapes coral reef community structure and photophysiology on the Pacific Coast of Costa Rica’An updated version of the OA-ICC bibliographic database is available online.
The database currently contains 9,859 references and includes citations, abstracts and assigned keywords. Updates are made every month.
The database is available as a group on Zotero. Subscribe online or, for a better user experience, download the Zotero desktop application and sync with the group OA-ICC in Zotero. Please see the “User instructions” for further details.
OA-ICC, 2 June 2026.
Upper-ocean variability of the marine carbonate system in the Northeast Pacific
Published 2 June 2026 Science Leave a CommentTags: chemistry, field, globalmodeling, modeling, North Pacific, regionalmodeling
In the Northeast Pacific, the marine carbonate system’s variability across timescales is not well constrained. Here, we quantify observed seasonal and non-seasonal variability in Dissolved Inorganic Carbon (DIC), partial pressure of carbon dioxide () and aragonite saturation state and discuss potential drivers. We used three decades of observations from four Line P time series stations, the longest marine carbonate system time series in the Northeast Pacific (1990–2019). To gauge the spatial extent of the variability patterns, we used output from a global ocean model representing the observed period. In the Northeast Pacific, seasonal and non-seasonal variability at 10 m was minimal, mostly damped by the opposing influence of DIC and temperature changes at both seasonal and interannual timescales. For DIC and , the seasonal cycle dominated total variability in the top 60–70 m, with mean-transect 10 m seasonal amplitudes of 35 3 μmol and 0.31 0.04, respectively. In the upper 60–70 m, the magnitude of non-seasonal variability was at least half that of the seasonal variability for most variables. From five climate indices examined, we focused on the basin-scale Pacific Decadal Oscillation index (PDO) to investigate potential drivers of non-seasonal variability, with 20%–40% of the non-seasonal variability in DIC and associated to this index. In the Northeast Pacific, positive PDO periods were linked to a mean reduction in 10 m DIC of 5 μmol and an increase in 10 m of 0.04 for each PDO unit increase, which could potentially reduce the occurrence and severity of ocean acidification events. The opposite could be expected during negative PDO periods.
Plain Language Summary
Using 30 years of observations from the Northeast Pacific, we characterized sources of variability for three marine carbonate system variables: , dissolved inorganic carbon (DIC) and the saturation state of aragonite (an common indicator of ocean acidification). The seasonal and non-seasonal variability was minimal in the top 10 m. The seasonal cycle of DIC and aragonite saturation state was the major contributor to total variability in the top 60–70 m, and not detectable below. Also, in the top 70 m of the water column, up to 20%–40% of the DIC and aragonite saturation state non-seasonal variability was associated to the Pacific Decadal Oscillation index (PDO). The PDO is a statistics-derived index that captures variability patterns influencing the whole Pacific basin and has a positive and negative phase. We found that a warmer than usual upper water column in the Northeast Pacific during a positive PDO phase, potentially driven by reduced mixing, was linked to a lower DIC and higher values of aragonite saturation state. The opposite could be expected during negative PDO periods. Knowing the magnitude of natural variability in the marine carbonate system is important to identify the emergence of ocean acidification and other human-driven changes in the ocean.
Continue reading ‘Upper-ocean variability of the marine carbonate system in the Northeast Pacific’Navigating the souring seas: the global experimentalist governance of ocean acidification
Published 2 June 2026 Science Leave a CommentTags: policy
Navigating the Souring Seas explores how ocean acidification (OA)-a significant yet under-governed environmental threat-is being addressed on the global stage. Bridging science, law, and international policy, this interdisciplinary book introduces global experimentalist governance as an innovative and adaptable framework for tackling complex and uncertain issues like OA. It provides a clear overview of the scientific background of OA and maps the international governance landscape, identifying it as a regime complex. Through detailed interview-based case studies of the Ocean Acidification Alliance and the International Maritime Organization, the book evaluates real-world efforts to govern OA and highlights how experimentalist features, such as flexibility, learning, and multilevel collaboration, can enhance their effectiveness. Accessible and timely, this book is essential reading for scholars, students, policymakers, and environmental practitioners seeking practical, forward-looking governance strategies for ocean and climate challenges. It offers both theoretical insight and concrete recommendations for improving global environmental governance.
Continue reading ‘Navigating the souring seas: the global experimentalist governance of ocean acidification’Hydrodynamic control of coral metabolism: a coupled modeling approach linking flow, physiology, and reef-scale biogeochemistry
Published 2 June 2026 Science Leave a CommentTags: biogeochemistry, biological response, chemistry, community composition, corals, individualmodeling, modeling, otherprocess, physiology, South Pacific
Tropical coral reefs exhibit high variability in coral metabolism, driven by complex interactions among physical, chemical, and biological processes. Understanding the spatiotemporal patterns of coral metabolism and their drivers is critical, as such variability may underpin corals’ adaptive capacity to withstand a warming and acidifying ocean. Here, we use a coupled hydrodynamic–biogeochemical–physiological model to investigate spatial and diel variations in coral metabolic processes (photosynthesis, respiration, and calcification) across Moorea’s north shore reef system under three prevailing wave regimes. We find that photosynthesis varies little across the reef, whereas respiration and calcification show pronounced spatial heterogeneity. These spatial patterns closely mirror the ones in seawater carbonate chemistry and depend strongly on wave-driven flow. Hydrodynamics regulate diffusive exchanges between coral tissues and surrounding seawater, and eventually generate distinct internal chemical environments (in the coelenteron and calcifying fluid) across the reef. Landward reef regions exhibit the greatest spatial and diel variability in coral metabolism. Low-wave, slow-flow conditions amplify metabolic fluctuations throughout the reef, but more strongly in the landward regions. Overall, our results highlight how interactions among transport processes, carbonate chemistry, and coral physiology produce strong day-night fluctuations and spatially heterogeneous but structured metabolic patterns across the reef, which vary systematically with wave conditions.
Continue reading ‘Hydrodynamic control of coral metabolism: a coupled modeling approach linking flow, physiology, and reef-scale biogeochemistry’
