Increasing atmospheric carbon dioxide (CO2) is driving global ocean acidification (OA). This process may threaten the persistence of bed-forming mussels by weakening the byssal system that anchors them to the seafloor. Here, blue mussels (Mytilus edulis) were exposed to present-day (∼460 ppm pCO2) normocapnic and projected end-century (∼1200 ppm pCO2) hypercapnic conditions for four weeks at 12 °C. Byssus production, thread morphology, whole-byssus mechanics and the underlying physiological condition index (CI) were quantified. Unlike previous studies, this study analysed the byssus as an intact functional unit. This approach better reflects its mechanical performance in situ. Median thread production fell by 50% under elevated pCO2 and the number of individuals producing no threads at all increased from 3% to 23% of the population. Thread diameter and plaque area were unaffected. Whole byssus tensile testing revealed a distinctive mechanical pattern (elastic loading, force plateau, and structural failure) regardless of environmental CO2 concentration. Whole byssus attachment strength scaled linearly with thread number in both treatments, and the mechanical work required to detach mussels under hypercapnia dropped by 42%. Elevated pCO2 reduced mussel condition index by 19% relative to the control, indicating an energetic burden. These results show that near-future ocean acidification weakens mussel attachment primarily by lowering individual physiological condition, which directly drives the reduction in total attachment energy, rather than by lowering individual thread quality. This likely results from a shift in energy use away from thread production, as seen in poorer mussel condition. As a result, mussels may become more prone to being dislodged by waves or predators. The findings of this study indicate that ocean acidification can reduce the overall strength of M. edulis beds, with important effects on rocky shore ecosystems and the viability of mussel farming in a changing climate.
Continue reading ‘Elevated pCO2 impairs overall byssus attachment strength in the blue mussel (Mytilus edulis) without altering byssus thread quality’Elevated pCO2 impairs overall byssus attachment strength in the blue mussel (Mytilus edulis) without altering byssus thread quality
Published 8 September 2026 Science Leave a CommentShark responses to ocean acidification: physiological buffering, behavioural vulnerability, and comparative insights from teleost fishes
Published 8 September 2026 Science Leave a CommentHighlights
- Sharks maintain acid-base balance under elevated CO₂ via effective buffering.
- Physiological compensation carries energetic costs that constrain aerobic scope.
- Olfactory-mediated foraging is more OA-sensitive than baseline locomotor function.
- Multi-stressor effects (warming + OA) amplify biological impacts across life stages.
- Evidence is biased toward benthic species; pelagic sharks remain understudied.
Abstract
Ocean acidification (OA), driven by increasing atmospheric carbon dioxide (CO₂), is a major component of global ocean change with widespread implications for marine organisms. Sharks (elasmobranchs) are often assumed to be relatively resilient to OA due to their distinctive physiology, including strong acid–base regulation and urea-based osmoconformation. However, empirical evidence evaluating this assumption remains limited and fragmented. This review synthesizes current knowledge on the physiological, behavioural, and sensory responses of sharks to OA within a comparative framework that incorporates insights from teleost fishes. A systematic literature search following PRISMA guidelines identified studies examining OA effects across shark species and life stages. Available evidence indicates that sharks generally maintain extracellular acid-base balance under elevated CO₂, demonstrating effective physiological buffering. However, this compensation is not without cost. Energetic trade-offs, reduced aerobic scope under multi-stressor conditions, and alterations in metabolic and oxidative responses have been reported. Behavioural and sensory-mediated processes, particularly olfactory-driven foraging, appear more sensitive to OA, with impairments emerging even in the absence of obvious physiological failure. Responses are highly species-specific and often amplified by co-occurring stressors such as warming. Despite these findings, current data are strongly biased toward small, benthic species, with limited representation of pelagic taxa and long-term responses. Sharks cannot be considered uniformly resilient to OA; rather, their responses are context-dependent, energetically constrained, and potentially consequential at population and ecosystem levels. Future research integrating long-term, multi-stressor, and mechanistic approaches will be critical for improving predictions of shark responses under ongoing ocean change.
Continue reading ‘Shark responses to ocean acidification: physiological buffering, behavioural vulnerability, and comparative insights from teleost fishes’High-resolution mapping of carbonate system parameters over coastal waters using integrated uncrewed aircraft systems (UAS) and Autonomous Surface Vessel (ASV) observations
Published 7 September 2026 Science Leave a CommentTags: chemistry, field, modeling, North Atlantic, regionalmodeling
Coastal acidification, distinct from ocean acidification, is influenced by localized factors such as nutrient runoff, freshwater input, and decomposition. This study estimates carbonate system parameters in the Western Mississippi Sound (WMS) using integrated uncrewed aircraft systems (UAS) and autonomous surface vessel (ASV) observations. During 2018 to 2022, high-ressolution UAS imagery and in 2021 in situ ASV data including pH, pCO2, SST, SSS, CDOM, and Chl-a were collected. Machine learning algorithms were developed to estimate pCO2 and total alkalinity (TA), with random forest models achieving high accuracy (R2 > 0.91). A CDOM-based model was developed to derive SSS, which, along with Chl-a, fed into time-series mapping of TA and pCO2. Results highlight the effectiveness of combining UAS and ASV data to produce fine-scale carbonate system maps. This approach supports improved monitoring of coastal acidification and can be extended to estimate additional parameters such as calcite and aragonite saturation states and DIC.
Continue reading ‘High-resolution mapping of carbonate system parameters over coastal waters using integrated uncrewed aircraft systems (UAS) and Autonomous Surface Vessel (ASV) observations’Air–sea CO2 exchange in the Southern Adriatic Sea: assessing its role as a moderate carbon sink over the last decade (2015–2024)
Published 7 September 2026 Science Leave a CommentTags: chemistry, field, Mediterranean
Coastal waters contribute significantly to the total oceanic carbon uptake. In this context, the cumulative influence exerted by marginal seas may be conspicuous. However sparse and unevenly distributed observations in such regions pose a serious limit to an accurate, experimentally based quantification of carbon dynamics. The Southern Adriatic (SAd) is one of the key sites of the Mediterranean Sea where open-ocean deep water formation occurs, a process recognized as a major driver of carbon sequestration. However, observations in this region remained sparse, thus quantitative assessment of surface carbon dynamics and air-sea carbon flux are still limited. In this study, a recently validated, decade-long (2015–2024) high-resolution time series of surface partial pressure of CO2 (pCO2 sw) and hydrographic measurements collected at the EMSO-E2M3A South Adriatic observatory, located at the centre of the Southern Adriatic Pit, has been analysed. The results showed that seasonal temperature variability and winter vertical mixing were the dominant drivers of pCO2 sw variability, with biological processes likely contributing during the post-convective period. Air–sea CO2 flux (FCO2), derived from in situ observations, indicated a clear seasonal pattern, with the SAd acting as a CO2 sink during winter and as a source during summer. Importantly, the results revealed that the SAd acted as a weak-to-moderate annual carbon sink over the last decade. However, the magnitude of FCO2 was strongly influenced by the selected gas transfer velocity parametrization. Similarly, the use of a different wind speed input, for instance ERA5 reanalysis, also altered the estimated CO2 flux, highlighting the importance of carefully selecting wind products for regional air-sea FCO2 calculations. Finally, the results presented here showed how time series such as the SAd dataset can serve as critical assets for validating operational ocean models, such as the European Copernicus Marine Service for the Mediterranean, by helping to identify discrepancies in the simulation of key processes.
Continue reading ‘Air–sea CO2 exchange in the Southern Adriatic Sea: assessing its role as a moderate carbon sink over the last decade (2015–2024)’| Apply to Join Pier2Peer! Pier2Peer is an international mentorship program that pairs mentees who are new to ocean acidification work with experienced mentors in the field. The program aims to foster community among ocean acidification (OA) professionals, build long-term capacity to measure and address OA globally, and provide training opportunities to support careers in OA-related fields. Pier2Peer is currently accepting applications for mentees and new mentors! Apply by 30 October 2026 to be considered for the 2026-2027 Pier2Peer Cohort. Before applying, please review eligibility requirements and terms of reference on the Pier2Peer webpage. |
Mentee Eligibility Requirements
If you are new to the field of ocean acidification, we encourage you to apply to be a Pier2Peer mentee. Pier2Peer mentees can be at any career stage. The time limit to be a Pier2Peer mentee is 2 years, so if you have already been a mentee for two years under a previous match, you are no longer eligible to apply for the Pier2Peer program as a mentee.
Mentees are expected to be self-motivated and to lead the interactions by reaching out to the mentor, introducing themselves, and scheduling the initial and following meetings. It is recommended that the mentee think about their goals and what they would like to accomplish through this mentorship. They are expected to show up prepared for each meeting and to be respectful of the time the mentor
Mentor Eligibility Requirements
Any GOA-ON member who is an experienced or senior-level scientist and is actively engaged in ocean acidification research is encouraged to become a Pier2Peer mentor. A Pier2Peer mentor should be willing to regularly communicate with their mentee and should be invested in their mentee’s professional growth. Pier2Peer mentors should also be excited about the opportunity to work with mentees whose backgrounds or experiences may be different from their own.
Mentors are expected to be responsive to the mentee in a timely manner and to help support the mentee’s goals to the best of their ability. The mentor can also consider opportunities that they become aware of within their network and pass them on to the mentee, whether or not those opportunities are directly related to the mentor’s work. Mentors will be contacted on an annual basis to confirm their availability for the upcoming cohort of mentees.
Terms of Reference
The Pier2Peer Program supports active mentee/mentor pairs for one year, with the option to renew for a second year. The limit to participate in the program as a mentee is 2 years. To be considered an active participant, mentees must (1) complete the entrance and exit surveys distributed by the Pier2Peer Coordinator and (2) be in regular contact with their mentor. Mentors and mentees are expected to meet at least quarterly during their time in the Pier2Peer program. Participants are expected to be reliable, enthusiastic, willing to learn and grow, open to sharing knowledge and perspectives, and have aligned expectations on what they hope to gain from the experience.
Following completion of the Pier2Peer program, certificates of completion will be awarded to Pier2Peer mentees in good standing. To earn a certificate, mentees must complete the entrance and exit surveys distributed by the Pier2Peer Coordinator and be in quarterly contact with their mentor and/or in attendance at 2 or more Pier2Peer events throughout their tenure as a mentee.
The Pier2Peer Coordinator facilitates mentor/mentee matching, organizes Pier2Peer programming, and serves as a general resource to help mentee/mentor pairs gain the most from their Pier2Peer experience. To date, the Pier2Peer Coordinator sits within the NOAA Ocean Acidification Program and also serves on the GOA-ON Secretariat.
The Matching Process
When new mentors register for the Pier2Peer Program, their information will be used to generate mentor profiles that will be added to a mentor directory. A mentor profile will consist of biographical data, information about a mentor’s research focus and expertise, and details about their mentorship style. The mentor directory will be updated annually to reflect mentors who are available to accept new mentees for the upcoming cohort.
After mentees are accepted into the Pier2Peer program, they will be directed to the list of available mentors and asked to rank up to five possible mentors with whom they would like to work. By giving new mentees the opportunity to browse the profiles of available mentors, they can identify individuals whose interests, skills, and expertise are most aligned with their specific needs. During this process, the Pier2Peer coordinator may also provide suggestions to the mentees based on their application materials.
The Pier2Peer Coordinator will then use all of the information gathered from the mentors and mentees to suggest new pairs. Participants will be notified of their match via an email containing the name, contact information, and country of their partner.
Continue reading ‘Join Pier2Peer!’Distributions and controls of carbonate parameters in offshore oil and gas fields of the Beibu Gulf and adjacent northern South China Sea (nSCS) shelf during the fall season
Published 4 September 2026 Science Leave a CommentTags: chemistry, field, North Pacific
Considering the strong seasonality in carbonate system parameters in coastal ecosystems, a comprehensive understanding of seasonal carbonate cycling is critically important for deploying scalable, nature-based negative emission technologies. Located in the northern South China Sea (nSCS), the Beibu Gulf is a semi-enclosed bay hydrodynamically connected to the nSCS shelf. Previous studies have documented carbonate dynamics in the Beibu Gulf during spring and summer; however, the spatial distributions and controlling mechanisms in fall remain unreported, as do comparative assessments with the adjacent nSCS shelf. Here, we present observations of the carbonate system in the Beibu Gulf and the adjacent nSCS shelf from a fall cruise conducted in 2024. Our results reveal that both the nSCS shelf and the Beibu Gulf act as CO2 sources with air-sea CO2 fluxes ranging from 0.4 to 1.6 mmol m−2 d−1. Although sea surface temperature exerts the dominant control on pCO2 variability, biogeochemical processes within the Beibu Gulf further elevate surface pCO2 by ∼20 μatm. In the water column, the spatial distributions of carbonate system parameters are primarily governed by the intrusion of SCS water and Kuroshio water. Notably, we report, for the first time, elevated dissolved inorganic carbon (DIC) and total alkalinity (TA) concentrations relative to background SCS water in certain bottom waters in Dongfang and Ledong within the Beibu Gulf, with increases of 94 ± 9 μmol kg−1 and 57 ± 3 μmol kg−1, respectively. Associated with these DIC and TA enhancements, we observed a concomitant increase in pCO2 of ∼92 μatm, alongside decreases in pH and aragonite saturation state (Ωarag) of 0.08 and 0.34 units, respectively. Qualitative analysis suggests that these DIC and TA additions likely originate from coupled CaCO3 dissolution and organic matter respiration, processes consistent with influences from submarine groundwater discharge (SGD) and/or sediment porewater release. However, these interpretations require further quantification and tracer-based validation.
Continue reading ‘Distributions and controls of carbonate parameters in offshore oil and gas fields of the Beibu Gulf and adjacent northern South China Sea (nSCS) shelf during the fall season’Characterizing decision optimization strategies for managing climate change impacts on aquatic ecosystems and public health in Asia
Published 4 September 2026 Science Leave a CommentTags: mitigation, North Pacific, review, socio-economy
Climate change is dramatically reshaping the delicate balance of Asia’s freshwater and marine ecosystems, intensifying threats to biodiversity, water quality, and public health. This review explores the profound interconnections between climate change and aquatic environments, highlighting the escalating risks posed by rising temperatures, shifting precipitation patterns, and extreme weather events. The paper delves into the alarming surge in harmful algal blooms, shifts in species distributions, and the increasing prevalence of waterborne diseases, all of which undermine both potable water sources and food security. In addition, the review examines the compounding impact of pollution, which further exacerbates the vulnerability of aquatic ecosystems. As global temperatures rise, the resulting decrease in dissolved oxygen and proliferation of pathogens create hostile environments for aquatic life, while extreme climatic events exacerbate water contamination and scarcity in many regions. Vulnerable communities, heavily reliant on aquatic resources for survival, face a dual challenge of environmental and socioeconomic instability. As Asia’s aquatic ecosystems continue to face unprecedented stress, proactive interventions are essential to safeguard food security, water resources, and public health for future generations.
Continue reading ‘Characterizing decision optimization strategies for managing climate change impacts on aquatic ecosystems and public health in Asia’An updated version of the OA-ICC bibliographic database is available online.
The database currently contains 9,974 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, 3 September 2026.
Physiology and hydrodynamics influence the susceptibility of reef-building corals to ocean acidification
Published 3 September 2026 Science Leave a CommentTags: biological response, community composition, corals, growth, laboratory, otherprocess, physiology
Ocean acidification (OA) poses a major future threat to tropical coral reefs. This is primarily due to its effects on reef-building coral species, which vary in their susceptibility to this climate change stressor. However, the potential factors underlying the range of susceptibilities observed among reef-building corals remain poorly understood. Therefore, this doctoral thesis investigates the influence of species-specific physiology and water flow conditions on coral susceptibility to OA. Using an experimental, multi-scale approach, the present thesis addresses this knowledge gap in a total of four studies and focuses on the physiological response of three major reef-building coral genera (Acropora, Pocillopora, and Porites) to prolonged exposure of OA conditions (> three months).
The results showed that (1) variable decreases in coral growth under OA were mediated by differential changes in maintenance and cellular stress parameters. This physiological interplay was genus-specific for Acropora and Pocillopora, and was species-specific for Porites spp. Moreover, assessments of the combined effects of OA and changes in water flow conditions indicated that (2) temporarily reduced water flow may mitigate OA effects on Acropora and Porites spp. Still, simultaneous changes in seawater chemistry and flow led to changes in coral physiology with complex and species-specific patterns. Finally, at the microscale, characterisation of the effects of OA and water flow on the concentration boundary layer (CBL) at the coral surface revealed that (3) OA was an overall weak modulator of this layer, regardless of flow conditions and CBL variability among species. Despite minor OA effects, however, the results also suggested that the CBL had a limited OA-buffering capacity due to thin pH gradients across the CBL. Nonetheless, low flow potentially enhanced CBL sheltering from acidified seawater by elevating pH at the coral surface.
In summary, this thesis provides evidence that both species physiology and water flow conditions shape coral susceptibility to OA in species-specific patterns and contributes novel insights into the potential links, between colony and CBL levels, involved in shaping it. Furthermore, the findings of this thesis showcase the potential of low-flow environments as refugia for coral species under OA and highlight the importance of including reef hydrodynamics in future OA scenarios, which will require consideration of different spatial and temporal scales. Altogether, the knowledge provided here may help improve projections of coral community dynamics under future OA and inform conservation efforts.
Continue reading ‘Physiology and hydrodynamics influence the susceptibility of reef-building corals to ocean acidification’Biological impacts of ocean change in upwelling systems: from organismal responses to fishery outcomes
Published 3 September 2026 Science Leave a CommentTags: arthropoda, biological response, calcification, crustaceans, echinoderms, fisheries, laboratory, mollusks, mortality, physiology
Climate change is altering marine ecosystems through concurrent changes in temperature, carbonate chemistry, and dissolved oxygen. These changes are particularly important in coastal upwelling systems, where organisms already experience naturally variable environmental conditions. This dissertation integrates synthesis, experimentation, and modeling to evaluate how ocean change influences marine invertebrates and the fisheries they support. First, I conducted a meta analysis examining the effects of ocean acidification and deoxygenation on marine invertebrates. Both stressors produced broadly negative effects on fitness-related
traits, including survival, growth, development, and reproduction. Although vulnerability varied among taxa, responses were not strongly structured across broad taxonomic groups, suggesting that species-specific traits and environmental history are important determinants of sensitivity. Second, I investigated the effects of multi-stressor upwelling conditions on juvenile Dungeness crab (Metacarcinus magister). Crabs maintained net calcification across a range of moderate conditions but exhibited significant declines under the most severe treatments, indicating threshold responses to environmental stress. Short-term environmental variability had little effect relative to mean conditions, suggesting that exposure severity is a stronger driver of performance than exposure pattern. Finally, I incorporated experimentally observed reductions in calcification into a size-structured yield-per
recruit model to evaluate potential fishery consequences. Reduced growth delayed attainment of legal harvest size and decreased projected fishery yield, demonstrating how sublethal physiological responses can scale to population and management-relevant outcomes. Together, these chapters show that ocean change can affect biological systems across levels of organization, from individual performance to fishery productivity. By linking broad patterns of vulnerability to species-specific responses and applied fishery outcomes, this dissertation provides a framework for understanding and managing the impacts of global change in coastal
marine ecosystems.
Chapter 22 – Environmental ethics and the case of ocean acidification
Published 2 September 2026 Science Leave a CommentTags: policy, socio-economy
Ocean acidification (OA) is a paradigm case of an encroaching long-term environmental problem that is mainly caused by CO2-emissions and will have diverse and often uncertain impacts on marine organisms and ecosystems. SDG 14 (‘Life below water’) demands to halt or slow down OA. Since occurrence of OA is remote to our daily terrestrial life, it has not been in the focus of moral attention so far. This chapter emerged from the BIOACID research programme at Kiel University. It examines five sources of normativity in environmental ethics, addresses problems of uncertainty and framing, and interprets the metaphor of ‘ocean health’ with recurrence to an updated version of Aldo Leopold’s principle. The chapter argues that basic non-anthropocentric approaches, such as biocentrism, ecocentrism, and holism, face severe problems with respect to marine environments and can’t serve as solid groundings for an ocean ethics. The chapter proposes that a deep anthropocentric environmental ethics can provide an appropriate grounding for ambitious marine stewardship policies, including ocean acidification. Finally, the chapter proposes to define a critical threshold for OA which should not be passed.
22.1 Introduction
This chapter addresses ocean acidification (OA) from an environmental ethics perspective. Ocean acidification is seen as a paradigm case for post-normal science. At its core, the chapter adopts and substantiates several ethical building blocks from a discourse-pragmatic approach, as (a) common heritage of humankind, (b) strong sustainability, (c) Aldo Leopold’s principle, and (d) ecosystem services, with a special eye on cultural services. The idea to attribute inherent moral value to marine organisms and ecological systems is seen critically.
This chapter emerged from the research programme BIOACID (Biological Impacts of Ocean Acidification) being conducted at Kiel University. Within the final period of the BIOACID research programme, a work package on environmental ethics was included to address the underlying normative issues. This project resulted in a monograph: Frederike Böhm and Konrad Ott, Impacts of Ocean Acidification: An Analysis from an Environmental Ethics Perspective (Böhm & Ott, 2019).1 The following chapter presents the essential lines of reasoning of this book and adds new thoughts. It is organized as follows: Section 22.2 gives a brief overview of the scientific dimension. Section 22.3 presents a post-normal-science framing of OA. Section 22.4 deals with interrelated sources of normativity which stem from environmental ethics. Section 22.5 addresses the problem of defining a planetary boundary for OA.
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Continue reading ‘Chapter 22 – Environmental ethics and the case of ocean acidification’Chapter 21 – How can we curb ocean acidification in a time of multiple competing crises?
Published 2 September 2026 Science Leave a CommentTags: policy, socio-economy
Since the 1972 Stockholm Conference, many global environmental agreements have been struck for climate, biodiversity, and sustainable development goals. Still, the planets environment has continued to decline, including on the ocean. One result has been ocean acidification, caused by the uptake of 30–40 per cent of all carbon dioxide from the atmosphere. On its face, this ocean CO2 uptake sounds positive. However, with a continuous increase of CO2 in the atmosphere, this also means an increase in the ocean, which alters its chemistry in ways that may disrupt oceanic biodiversity through making waters more acidic. When coupling this with other major global crisis, we see that we have only adopted global environmental agreements that protect humans from our own nature-induced change – and not ensured that we take our ethical obligation to nature itself by protecting it from human use. This chapter looks at the risk perception literature and considers how the science–policy interface can be exploited to convey the importance of ocean acidification, and whether the anthropogenic lens is what will always be necessary to ensure action to protect something from ourselves.
21.1 Introduction
Around the end of the eighteenth century, with the design of the steam engine by James Watt, the geological age of the Anthropocene started (Crutzen 2006). This has led to unprecedented changes in the natural environment, the most serious of which is climate change. We have tried to change our paths since then though. In fact, more than 50 years have now passed since the 1972 Stockholm Conference (Rockström et al. 2021) – the United Nations Conference on the Human Environment. This was when global leaders for the first time made the environment and the triple planetary crisis of climate, nature, and pollution a focus issue. At that time, in 1972, they warned – and this still holds true today – that ‘Through ignorance or indifference we can do massive and irreversible harm to the earthly environment on which our life and well-being depend’ (United Nations 1973).
Since then, state leaders have created the United Nations Environment Programme (UNEP) entered into force both a climate and biodiversity agreement (United Nations Framework Convention on Climate Change (UNFCCC) and the Convention on Biological Diversity (CBD)) with many iterations; signed the UN 17 Sustainable Development Goals (SDGs) in 2015 with corresponding targets, as part of the realization of Agenda 2030; and in 2022 and 2023, state leaders also signed the Kunming-Montreal Global Biodiversity Framework (GBF) and the Agreement under the United Nations Convention on the Law of the Sea on the conservation and sustainable use of marine biological diversity in areas beyond national jurisdiction (BBNJ). Still, we have continued to saturate Earth’s capacity to support future generations (Intergovernmental Panel on Climate Change 2018). The planet is more polluted than earlier, there are fewer fish in the ocean, the temperature is increasing, methane levels are at their highest in 800,000 years, polar regions are melting, plastics are ubiquitous, and the ocean is more acidic than ever (Barnes & Kaiser 2009; Hönisch et al. 2012; Worm & Branch 2012; MacLeod et al. 2021; Intergovernmental Panel on Climate Change 2022).
In fact, six of nine planetary boundaries that are needed for humans to be able to develop and thrive for generations to come have been breached already (Richardson et al. 2023). Then, in 2025, the ocean acidification boundary was crossed (Findlay et al. 2025). This is a boundary that is also specifically mentioned in the SDGs, with target 3 of SDG14 Life below water specifying the need to ‘Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels’. It was in fact the only by-product of climate change and greenhouse gas emission that was singled out to be included under this goal (United Nations Department of Economic and Social Affairs 2022). Still, there is a lack of concrete knowledge of how breaching this boundary will impact either non-human populations or the corresponding human population that depends on these (Buckley et al. 2017).
In light of this, the current chapter considers ocean acidification within the planetary boundaries framework and assesses the lack of responses that led to, and may further exacerbate, the breaching of this boundary. We argue that this in part can be explained by the human-centric perspective of global environmental governance, where effective governance is linked to risk perception within a human context. In terms of ocean acidification, we argue that humans still have a low personal risk perception, coupled with a lack of knowledge (or interest) about it, which directly hinders its agenda setting and implementation of effective governance. We conclude with considering whether the increased saliency of biodiversity challenges, as brought to the surface with the signing of the GBF in 2022, can bring more attention to the role of stressors such as ocean acidification on sustainability and the consequences the breach of this planetary boundary can have on not only humans but also non-human populations.
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Continue reading ‘Chapter 21 – How can we curb ocean acidification in a time of multiple competing crises?’Chapter 20 – Introduction to the ocean acidification boundary
Published 2 September 2026 Science Leave a CommentTags: policy, socio-economy
The oceans mirror many of the environmental problems described in the planetary boundaries framework and reported widely in the media, such as overfishing and deep-sea mining (biosphere integrity), plastic islands or microplastics (novel entities), shipping (atmospheric aerosol loading), or dead zones lacking oxygen (biogeochemical flows). Less present in the media is the problem of ocean acidification addressed by the planetary boundary. Like the atmosphere, the oceans are sinks for CO2 produced by the burning of fossil fuels.
CO2 absorption changes the chemistry of the oceans, lowering their pH. The resulting acidification also leads to fewer of the calcium carbonate shells produced by numerous creatures sinking carbon to the ocean floor before they dissolve back into the water. The boundary’s control variable relates to this by describing the ‘carbonate ion concentration in surface seawater’ and, more specifically, the ‘average global surface ocean saturation state with respect to aragonite’ (Richardson et al. 2023). Aragonite is one of the most abundant forms of calcium carbonate. The boundary is at more than 80 per cent of the pre-industrial aragonite concentration, defined as 3.44. In 2023, the level was 81 per cent, meaning the ocean boundary was, at that time, still one of the few that had not been crossed. Thus, Pelejero et al. (2010: 332) describe ocean acidification as the ‘“evil twin” of global warming’ – it is a moot question, though, as to which is of the two is more evil. This also means that reducing greenhouse gas emissions will reduce the pressure on ocean acidification.
Acidification of the oceans and declining concentrations of calcium carbonate are becoming a problem for marine life. Many creatures depend on the presence of these calcium compounds in the water to build their shells or skeletons. Lower pH not only erodes the existing structures of these creatures, but they also find less calcium to rebuild them. These include plankton, corals, crustaceans, and molluscs, which are vital to marine biodiversity, marine food chains, and, ultimately, human food security (Rockström et al. 2009). So, the control variable of the ocean boundary is the global average saturation state of calcium carbonate in surface water. The framework sets the preindustrial Holocene base value at 3.44 and the boundary value at 2.75. Since 2009, the actual values have fluctuated between 2.8 and 2.9 (Richardson et al. 2023). In 2025, the ocean acidification boundary was first recognized as having been crossed (Findlay et al. 2025).
Both chapters on ocean acidification take the problem structure of the ocean acidification boundary as the starting point of their ethical reflections. Konrad Ott describes it as post-normal, that is, a situation when problem-solving has to cope with uncertain facts, disputed values, high-stakes, and urgent decisions (Funtowicz & Ravetz 1993). Ott explores the issue of ocean acidification from an environmental ethics perspective. He discusses different ways of justifying why ocean acidification is an ethical problem and what follows from this. In doing so, he aims to show how well the most common environmental ethical approaches can address the issue. They mostly differ in their scope of the moral community, that is, to whom we have direct moral obligations: to humans only, or also to individual animals, species, or ecosystems? Depending on the answer one gives, the reasons for protecting oceans will change. Ultimately, Ott intends to specify the normative building blocks of deep anthropocentrism as his preferred approach to the issue.
Rachel Haug Fossbakk, too, addresses the issue of decision-making relating to uncertainty and risk perception. She argues that the human response to ocean acidification is inadequate. This is despite the fact that there is already enough knowledge to act. Her hypothesis is that action requires an adequate perception of risk, which many people do not have when it comes to ocean acidification. She concludes by asking who has a responsibility to act, and on what ethical basis. Rachel Haug Fossbakk then advocates an ecocentric perspective by which she understands a situation ‘where humans are part of nature and need to live sustainably as part of it on the same term as other species’.
Continue reading ‘Chapter 20 – Introduction to the ocean acidification boundary’Climate change is ocean’s biggest threat: Pacific Ocean Commissioner
Published 2 September 2026 Media coverage , Web sites and blogs Leave a Comment
Time flies – the Ocean Acidification News Stream celebrated its 20th anniversary this summer! The very first post on this news stream goes back to 5 July 2006.
Some stats for the past 20 years:
- Close to 20,000 posts
- More than 1,9 million views
- Close to 630,000 visitors
- Country affiliation of top 10 visitors: US, France, China, Australia, UK, Canada, Germany, India, New Zealand, Spain
A word from the founder, Jean-Pierre Gattuso, CNRS-Sorbonne Université Laboratoire d’Océanographie:
I could not have imagined, back in 2006, that the blog I started would still exist 20 years later! At the time, ocean acidification was not a prominent topic on the research agenda. It gained momentum with the European Project on Ocean Acidification, followed by many other projects, both small and large. I am deeply grateful to the IAEA Ocean Acidification International Coordination Centre and everyone who has maintained the news stream over the years, beginning with Lina Hansson and continuing with the current caretaker, Carolina Galdino.
Current and past contributors:
- Carolina Galdino
- Courtney Witkowski
- Lina Hansson
- Sarah Flickinger
- Olga Anghelici
- Frank Graba
- Nicholas Theux Lowen
- Ashley Bantelman
- Trevor Eakes
- Einat Adam
- Tanmay Misra
- Hasti Dessa
- Anne-Marin Nisumaa
- Jean-Pierre-Gattuso
Thank you to all followers, and, as always, don’t hesitate to contact the team to suggest improvements or send us information that you would like to share!
Continue reading ‘The Ocean Acidification News Stream turns 20!’The Global Ocean Data Analysis Project version 3 (GLODAPv3) – an internally consistent biogeochemical data product for the world ocean
Published 1 September 2026 Science Leave a CommentTags: chemistry, field
The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing surface-to-bottom ocean biogeochemical observations determined through chemical analysis of discrete bottle samples, with an emphasis on seawater inorganic carbon chemistry and related variables. Version 3 of GLODAP comprises data from 1181 cruises, spanning more than 50 years of observations (1972–2023). It includes all data from the previous GLODAPv2.2023 (Lauvset et al., 2024) together with newly added data from 57 cruises. For all cruises, 13 core variables (temperature, salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, CFC-11, CFC-12, CFC-113, CCl₄, and SF6) have undergone extensive quality control with particular focus on the identification and removal of systematic differences between cruises. The data are available in two formats: (i) as submitted by the data originators, converted to World Ocean Circulation Experiment (WOCE) exchange format, and (ii) as a merged data product in which adjustments have been applied. These adjustments were determined using crossover analyses in combination with a newly developed global inversion method, the furthest-first routine. The applied adjustments are intended to remove systematic differences arising from differences in measurement methods, calibration, and/or data-handling practices, while preserving known or likely temporal trends and natural variability. The consistency of the adjusted data product is estimated to be 0.0013 for salinity, 0.7 % for oxygen, 0.4 % for nitrate, 0.5 % for silicate, 0.5 % for phosphate, 1.2 µmol kg⁻¹ for dissolved inorganic carbon, and 1.4 µmol kg⁻¹ for total alkalinity. Consistency estimates could not be derived for transient tracers, but they are believed to be consistent to better than 5 % (10 % for SF₆). The enhanced consistency enables different datasets to be used together with greater confidence. Newly introduced cruise-specific uncertainty estimates for all core variables provide more granular quantifications of remaining cruise-to-cruise inconsistencies. Additional variables, including pH, discrete CO₂ fugacity (fCO₂), isotopic tracers, and others, were not subjected to secondary quality control but are included in the data product.
The original data, their documentation (metadata), and DOIs are available through the Ocean Carbon and Acidification Data System (OCADS) of NOAA’s National Centers for Environmental Information (NCEI), which also hosts the merged data product. All secondary quality control decisions and supporting information can be found in the online adjustment table (https://glodapv3.geomar.de, last accesses 26.06.2026). The product is distributed as a single global file and as four regional subsets (Arctic, Atlantic, Indian, and Pacific Oceans) under https://doi.org/10.25921/m6tp-mj50 (Lange et al., 2026). These adjusted files also include ancillary and approximated data obtained through interpolation or calculation from measured data.
Continue reading ‘The Global Ocean Data Analysis Project version 3 (GLODAPv3) – an internally consistent biogeochemical data product for the world ocean’Climatic factors effects on gastropods (Phylum: Mollusca): a review of the biodiversity of freshwater, marine, and terrestrial snails
Published 1 September 2026 Science Leave a CommentTags: biological response, mollusks, review
Climate change is altering ecosystems worldwide through rising temperatures, changing precipitation patterns, and more frequent extreme weather events, including heatwaves. Gastropods in freshwater, marine, and terrestrial environments are affected through changes in habitat characteristics, geographic distribution, abundance, physiology, and behavior. In freshwater systems, warming and drought can reduce dissolved oxygen and shrink suitable habitats. In marine environments, ocean acidification can impair shell formation and, under severe conditions, dissolve calcium-carbonate shells. In terrestrial habitats, increasing temperature and declining soil moisture can force snails into prolonged inactivity and increase desiccation risk. Effective climate information, predictive models, and early-warning systems are therefore essential for climate resilience, biodiversity conservation, and disease-risk management. Further comparative research is needed to clarify how phylogenetic history and adaptive variation influence heat tolerance and resilience among gastropod taxa.
Continue reading ‘Climatic factors effects on gastropods (Phylum: Mollusca): a review of the biodiversity of freshwater, marine, and terrestrial snails’Seasonal forecasts of pH and aragonite saturation for the Bering Sea Shelf
Published 1 September 2026 Press releases Leave a CommentSimilar to weather forecasts for the atmosphere, numerical models can also be used to forecast ocean conditions. Since the ocean changes more slowly, particularly below the surface, forecasts of ocean conditions can be made for multiple months out. These forecasts can be helpful for marine resource managers by providing early warning of anomalous events, such as marine heatwaves or more acidic ocean conditions.
A new study, focused on the Bering Sea, tested an ocean model to see if it was capable of forecasting acidified bottom water conditions several months in advance. The cold and carbon rich waters of the Bering Sea make the region vulnerable to ocean acidification (OA) due to the naturally low carbonate saturation states. Scientists assessed the ocean model by running a suite of reforecasts (retroactively forecasting previous years) and comparing to the conditions that did occur.
They found that the ocean forecasting model was skilled at predicting anomalies in bottom water pH on lead times up to nine months owing primarily to strong persistence. However, predictive skill for finer scale spatial anomalies was more limited and variable. They found that the model can be an effective tool to notify marine resource managers several months in advance of the expected development of relatively more acidic water conditions. This early warning can enable managers to make tactical decisions regarding upcoming fisheries quotas and assist rebuilding plans following fishery closures, such as the red king crab fishery that has faced recent closures and is threatened by OA.
Learn how NOAA Pacific Marine Environmental Laboratory studies the ecosystems of the North Pacific Ocean, Bering Sea and U.S. Arctic to improve understanding of ecosystem dynamics and applies that understanding to the management of living marine resources by clicking here.
Continue reading ‘Seasonal forecasts of pH and aragonite saturation for the Bering Sea Shelf’SDG14 assessment of progress against sustaining life below water: a case study from Torres Strait
Published 31 August 2026 Science Leave a CommentTags: crustaceans, fisheries, socio-economy, South Pacific
The United Nations Sustainable Development Goals (SDGs) represent a global call for action to sustain humans, the planet and prosperity. SDG14 (Sustaining Life below water) focuses on oceans, their conservation and sustainable use. Since committing to the 2030 Agenda for Sustainable Development, there have been several calls to take stock of progress and encourage decisive action to build a sustainable future. Here we evaluate progress against achieving each of the SDG14 goals using as an example Australia’s Torres Strait tropical rock lobster (TRL) Panulirus ornatus fishery because of the very strong dependence of Indigenous fishers and local communities on this resource. Our evaluation draws on 40 years of research, highlighting how changes have improved alignment or are on-track to meet the 2030 targets. We assessed that all targets were achieved to 2025 due to the small fishery ecological footprint, sound sustainable fishery and ecosystem management, science-based management plans, economic benefits derived though sustainable management, growth in research capacity as well as access for small-scale artisanal fishers to marine resources and markets. Our case-study therefore complements best practices examples in achieving SDG14 for a regionally important fishery. To meet 2030 aspirational goals, progress was assessed as on-track to address impacts of ocean acidification, enhanced transfer of marine technology and need to work with global partners to encourage market access for sustainable fisheries that are vital in supporting Indigenous and regional livelihoods. Overall, we calculated a conservative score of 3.5 reflecting very high achievement (~ 88%) towards future aspirational SDG targets.
Continue reading ‘SDG14 assessment of progress against sustaining life below water: a case study from Torres Strait’What can a lobster fishery teach us about SDG 14?
Published 31 August 2026 Web sites and blogs Leave a CommentAs the deadline for the United Nations Sustainable Development Goals approaches, there is increasing interest in understanding where progress is being made and what practical examples can offer useful lessons. A new, open access article in Reviews in Fish Biology and Fisheries takes this perspective to the ocean, using the Torres Strait tropical rock lobster fishery in northern Australia as a case study to assess progress toward SDG 14, the goal focused on conserving and sustainably using marine resources.
The fishery is unusual in several respects. Tropical rock lobster (Panulirus ornatus) is a high-value species that supports livelihoods in Torres Strait communities, where Indigenous peoples have managed and depended on marine resources for generations. The fishery is also jointly connected to Australia and Papua New Guinea through the species’ migratory life cycle and shared management arrangements.
Drawing on four decades of scientific monitoring, the authors evaluated progress across all ten SDG 14 targets. Their assessment highlights a combination of factors behind positive outcomes, including long-term ecological surveys, science-based stock assessment, precautionary fisheries management and strong participation from Indigenous fishers and communities. According to the study, the fishery currently meets the SDG 14 targets that can be assessed against present-day conditions and shows substantial progress toward the longer-term aspirational goals for 2030.
Ecological footprint
One aspect of the case study that stands out is the fishery’s relatively small ecological footprint. Lobsters are collected by hand rather than through trap-based methods, reducing impacts on habitats and limiting the amount of fishing gear deployed in the environment. The article also describes how monitoring programs have evolved over time, incorporating new technologies and extensive fishery-independent surveys while maintaining continuity in the data needed for management decisions.
The authors are careful not to present the fishery as a finished success story. Some targets remain works in progress, particularly those related to the impacts of ocean acidification, technology transfer and broader international cooperation that can help support sustainable fisheries and market access. The study also notes that external pressures, including marine pollution transported from outside the region and environmental variability affecting lobster recruitment, continue to require attention.
While the findings are specific to Torres Strait, the paper offers a useful example of how sustainability goals can be evaluated using long-term evidence rather than broad assumptions. For researchers working on fisheries, marine conservation, resource management or sustainability policy, it provides a detailed look at how local practices, community engagement and sustained scientific investment can be brought together to track progress toward global environmental objectives.
Continue reading ‘What can a lobster fishery teach us about SDG 14?’
