Climate change threatens shellfish aquaculture worldwide, with ocean acidification (OA) accelerating shell dissolution and reducing calcification, hindering growth. This study addressed the negative impacts of OA on juvenile red abalone (Haliotis rufescens), a life stage that is particularly susceptible to climate stressors, and the ability of the red seaweed, dulse (Devaleraea mollis), to mitigate these effects. I tested the hypothesis that Integrated Multi-Trophic Aquaculture (IMTA), with abalone and seaweed grown in co-culture, can raise seawater pH through photosynthesis to yield more favorable conditions for abalone growth and shell construction. A 5-month experiment was conducted to determine the benefits of IMTA on abalone growth, shell composition, and morphology under simulated ocean acidification conditions. In each tank, 620 abalone were raised in either High (8.1 ± 0.3), Ambient (7.9 ± 0.2), Medium (7.8 ± 0.3), or Low pH (7.6 ± 0.2). Abalone raised in High and Ambient pH treatments exhibited greater shell length, weight, area, and condition compared to those raised in medium and low pH treatments. Shell analyses indicated that these growth differences translate into differences in physical and chemical properties, with shells from the high and ambient pH treatments containing higher levels of Mg2+ and being more resistant to fracturing. These findings indicate that IMTA could shepherd abalone through the susceptible juvenile stage, increasing resilience of abalone aquaculture even within the context of future climate change.
Continue reading ‘Abalone and seaweed co-culture: growth and shell biomineralization of an iconic California gastropod’Posts Tagged 'mitigation'
Abalone and seaweed co-culture: growth and shell biomineralization of an iconic California gastropod
Published 5 August 2025 Science ClosedTags: algae, biological response, chemistry, fisheries, laboratory, mitigation, mollusks, morphology, physiology, reproduction
Potential for regional resilience to ocean warming and acidification extremes: projected vulnerability under contrasting pathways and thresholds
Published 30 July 2025 Science ClosedTags: adaptation, biogeochemistry, chemistry, globalmodeling, mitigation, modeling, otherprocess
We analyze the frequency and amplitude of projected warming and ocean acidification extremes under high CO2 and strongly mitigating scenarios. We find interpretational differences in projections arising from methodological choices associated with specification of stressor thresholds. Use of absolute versus distribution-based thresholds, and, in the distribution-based case, the inclusion or exclusion of seasonal variability, can lead to very different regional patterns in projected stress. The choice of fixed versus adaptive baseline, for example, determines whether future stress frequency in the low-CO2 scenario most closely resembles that in the high-emissions scenario or historical period. We find that mitigation through emissions reductions, in combination with representation of rates of adaptation that are realistic for some marine organisms, has the potential to dampen end of century threshold exceedance to frequencies of occurrence closer to the recent historical period than to the high-emissions scenario.
Continue reading ‘Potential for regional resilience to ocean warming and acidification extremes: projected vulnerability under contrasting pathways and thresholds’Harnessing nature’s buffer: assessing the role of bivalve shells in coastal alkalinity regeneration
Published 15 July 2025 Science ClosedTags: chemistry, field, mitigation, North Atlantic
Bivalve shells, a natural alkaline material, play a crucial role in coastal carbon cycles by influencing total alkalinity (TA) and dissolved inorganic carbon (DIC). This study investigated oyster shell dissolution in Narragansett Bay, Rhode Island, under varying pCO2 conditions, revealing TA regeneration rates of 4–56 μmol L-1 d-1, which could mitigate localized ocean acidification (OA). Notably, significant dissolution occurred even in oversaturated waters (Ωcalcite > 1) due to corrosive microenvironments created by microbial respiration. Although shell formation (calcification) emits CO2, TA regeneration (shell dissolution) buffers OA when the carbonate chemistry of the water is corrosive, offsetting the initial CO2 emissions. Therefore, recycling shells enhances ecosystem resilience by buffering acidification stress for OA-sensitive organisms. This research highlights the need to revisit shell management policies to promote sustainable aquaculture and sheds light on the potential of incorporating this nature-based alkaline material into ocean alkalinity enhancement strategies for improved coastal carbon management.
Continue reading ‘Harnessing nature’s buffer: assessing the role of bivalve shells in coastal alkalinity regeneration’Quantifying farmed kelp atmospheric CO2 uptake through localized air-sea flux in the Northern Gulf of Alaska
Published 14 July 2025 Science ClosedTags: chemistry, field, fisheries, mitigation, North Pacific
The rapid growth of mariculture in the United States, particularly in Alaska, has ignited interest in the co-benefit of using farmed kelp as a mitigation strategy against anthropogenic carbon dioxide (CO2) released to the atmosphere. Here, we quantified the air-sea CO2 flux in three kelp farms across the Northern Gulf of Alaska with differing oceanographic conditions and farming practices to determine the carbon sequestration potential over the growing season. Sensors were deployed on two subsurface moorings placed in proximity of one another at each farm site: one “inside” and one “outside” as a control upstream of the farm. Both sensor arrays conducted hourly measurements of pH or CO2, temperature, salinity, and oxygen during the time from seed line outplanting in winter (November to January) to spring harvest (April or May) in 2024. Nominal differences in carbonate chemistry parameters were detected between the inside and outside moorings until March, when the frequency of variability remained consistent between moorings but their respective magnitude diverged. Notably, apparent oxygen production, seawater CO2 concentration, air-sea CO2 flux, and strength of periodic signals varied by farm site. Integrated over the entire deployment, two farms demonstrated net negative air-sea CO2 fluxes while one served as a net source of carbon: -84,397 ± 41,374 mol m2 in Jakolof Bay, -11,115 ± 1,331 mol m2 in Kalsin Bay, and 543 ± 21 mol m2 in Windy Bay. This study highlights the nuance of farmed kelp carbon capture by demonstrating that farm site can influence overall air-sea CO2 flux and that kelp farms are not always a net sink for atmospheric carbon.
Continue reading ‘Quantifying farmed kelp atmospheric CO2 uptake through localized air-sea flux in the Northern Gulf of Alaska’Ocean acidification: impacts on marine ecosystems
Published 11 July 2025 Science ClosedTags: biological response, chemistry, education, mitigation, review
Ocean acidification, driven primarily by increased atmospheric CO₂ absorption, is one of the most pressing environmental challenges of our time. This paper examines the chemical mechanisms underlying acidification, its historical trends, and the widespread implications for marine organisms and ecosystems. It examines physiological and ecological effects on species ranging from microscopic plankton to coral reefs and addresses broader ecosystem-level disruptions and their cascading impacts. The socioeconomic implications, particularly for coastal communities and fisheries, are evaluated alongside mitigation strategies and the importance of long-term research and monitoring. The study underscores the urgency of interdisciplinary approaches to understanding and combating ocean acidification as part of the global climate agenda.
Continue reading ‘Ocean acidification: impacts on marine ecosystems’Handling the heat: ocean acidification mitigates the effects of marine heatwaves on Posidonia oceanica seedlings
Published 8 July 2025 Science ClosedTags: biological response, laboratory, Mediterranean, mitigation, molecular biology, multiple factors, phanerogams, photosynthesis, physiology, reproduction, respiration, temperature
Ocean acidification (OA) and marine heatwaves (MHWs) are key drivers of marine ecosystem changes that can interact and influence marine organisms. Seagrasses, including the long-lived Posidonia oceanica endemic to the Mediterranean Sea, are widely distributed along coastal habitats, forming highly valuable underwater meadows. The germination and survival of the early life stages of P. oceanica are strongly affected by environmental changes. To assess the impact of warming and acidification on its future, we conducted a multifactorial experiment where P. oceanica seedlings were grown under OA conditions for six months and then exposed to a seawater warming event. Seedlings’ performance was investigated by analyzing photo-physiology, antioxidant capacity, energetic metabolism and transcriptomic profiles. The Weighted Gene Correlation Network Analysis (WGCNA) was used to integrate phenotypic plant traits with transcriptomic results to identify central genes involved in plant responses to OA and temperature exposure. Results demonstrated that prolonged OA exposure enhances P. oceanica seedling resilience to MHW. Specifically, seedlings regulated their antioxidant systems and transcriptomic machinery to better cope with thermal stress. Under current CO2 concentrations, elevated temperatures induced stress in P. oceanica seedlings, impacting photosynthesis and respiration. However, OA could mitigate the impact of warming in the future, enhancing P. oceanica‘s resilience to global stressors.
Continue reading ‘Handling the heat: ocean acidification mitigates the effects of marine heatwaves on Posidonia oceanica seedlings ‘Something in the water: how kelp is helping Maine’s mussels boom
Published 8 July 2025 Media coverage ClosedTags: mitigation, North Atlantic
On a glimmering May morning, Tom Briggs pilots a 45ft aluminium barge through the waters of Casco Bay for one of the final days of the annual kelp harvest. Motoring past Clapboard Island, he points to a floating wooden platform where mussels have been seeded alongside ribbons of edible seaweed.
“This is our most productive mussel site,” says Briggs, the farm manager for Bangs Island Mussels, a Portland sea farm that grows, harvests and sells hundreds of thousands of pounds of shellfish and seaweed each year. “When we come here, we get the biggest, fastest-growing mussels with the thickest shells and the best quality. To my mind, unscientifically, it’s because of the kelp.”
A growing body of science supports Briggs’s intuition. The Gulf of Maine is uniquely vulnerable to ocean acidification, which can impede shell development in mussels, clams, oysters and lobster, threatening an industry that employs hundreds of people and generates $85m to $100m (£63m to £74m) annually.
Atmospheric carbon dioxide from fossil fuels is the main driver of declining ocean pH, increasing the acidity of the world’s oceans by more than 40% since the preindustrial era and by more than 15% since 1985. Add carbon runoff from growing coastal communities, regular inflows of colder, more acidic water from Canada, and intense thermal stress – the Gulf of Maine is warming three times faster than the global average – and you’re left with a delicate marine ecosystem and key economic resource under threat.
Enter kelp. The streams of glistening, brownish-green seaweed that Bangs Island seeds on lines under frigid November skies and harvests in late spring are a natural answer to ocean acidification because they devour carbon dioxide. Sensors placed near kelp lines in Casco Bay over the past decade have shown that growing seaweed changes water chemistry enough to lower the levels of carbon dioxide in the immediate vicinity, nourishing nearby molluscs.
Continue reading ‘Something in the water: how kelp is helping Maine’s mussels boom’The coupled oxygen and carbon dynamics in the subsurface waters of the Gulf and Lower St. Lawrence Estuary and implications for artificial oxygenation
Published 7 July 2025 Science ClosedTags: biogeochemistry, chemistry, mitigation, modeling, North Atlantic, regionalmodeling
The Gulf and Lower St. Lawrence Estuary have experienced major environmental change over the past century, including the development of hypoxic bottom waters and their simultaneous warming and acidification. Here, we use biogeochemical observations collected during the 2021–2023 TReX project as well as historical data, combined with a tracer-calibrated 1D Advection-Diffusion model with variable boundary conditions to represent dissolved oxygen (DO) and dissolved inorganic carbon (DIC) dynamics within the core of the oxygen minimum zone (27.15–27.3 kg m-3 isopycnals) of the Laurentian Channel. The rate of in-channel oxygen utilization in the deep layer was nearly invariant from 2003 to 2023 at 21.1 ± 2.5 µmol kg-1 yr-1 and the DIC accumulation rate was estimated to be 18.3 ± 2.5 μmol kg-1 yr-1. Using δ13CDIC data, we assess the effect of microbial organic matter remineralization processes and dilution of the 13CDIC pool (−6.6×10-3 ‰ per μmol of added metabolic DIC). These data and the use of a tracer-calibrated model to resolve advection and mixing dynamics reconcile differences in prior estimates of biogeochemical transformation rates. Finally, we apply the model to the mitigation scenario proposed by Wallace et al. (2023) for artificial re-oxygenation of the Laurentian Channel bottom waters using pure oxygen. We estimate that the injection of ~8.3 × 105 tonnes yr-1 of oxygen, equivalent to an additional 55 μmol kg-1 relative to the 2023 boundary concentration proximal to the Cabot Strait, would be required to achieve and maintain above hypoxic levels (>62.5 μmol kg-1) at the head of the Laurentian Channel. Using the model, we estimate the time required to re-establish steady-state along-channel distributions of DO and DIC following a change in offshore boundary conditions to be about 10 years, or twice the along-channel transit time.
Continue reading ‘The coupled oxygen and carbon dynamics in the subsurface waters of the Gulf and Lower St. Lawrence Estuary and implications for artificial oxygenation’Seaweed responses to ocean acidification: global impacts on growth, biochemical composition, and CO2 mitigation potential
Published 3 July 2025 Science ClosedTags: biological response, mitigation, phanerogams, physiology, review
Ocean acidification, driven by the absorption of elevated atmospheric CO2 levels, significantly affecting the growth and nutritional composition of marine biota, including seaweeds. The increasing expansion of the cultivation of seaweed is a promising method for removing carbon dioxide through both government and private sectors. There are notable comprehensive assessments that evaluated the effectiveness of seaweed farming to achieve significant climate change mitigation and it ended with positive outcome. Hence the present article reviews about the global impacts of ocean acidification on seaweed communities including growth dynamics, nutritional trends, and their potential for CO2 mitigation. The ecological consequences of ocean acidification and providing an overview of its status. Amplified CO2 levels affect seaweed physiology and ecosystem dynamics that have an influence on biodiversity, carbon cycling, and nutrient flows. The review highlights the trends in seaweed growth under elevated CO2 conditions, through identification of both opportunities and challenges for maintenance of productivity and nutritional quality. Seaweeds exhibit potential for CO2 sequestration, that whorls to offset carbon emissions through aquaculture practices. Furthermore, integrated seaweed farming practices can enhance environmental benefits, such as biodiversity conservation, nutrient remediation, and improved carbon storage. Finally, yet importantly this article emphasizes the necessity for targeted research that aimed at optimization of seaweed cultivation techniques, decipher species-specific responses to ocean acidification, and leveraging biotechnological advancements for maximation in mitigation of CO2. The findings underscore the role of seaweed aquaculture as a sustainable strategy to combat climate change and protect marine ecosystems.
Continue reading ‘Seaweed responses to ocean acidification: global impacts on growth, biochemical composition, and CO2 mitigation potential’Biophysical model of eelgrass and water quality in Coos Bay, OR shows greater mitigation potential for ocean acidification than hypoxia
Published 30 June 2025 Science ClosedTags: biological response, chemistry, communitymodeling, mitigation, modeling, North Pacific, phanerogams
Seagrass beds provide important ecosystem services and are valued, in part, for their potential to mediate stressors such as ocean acidification and hypoxia (OAH) for sensitive species. However, the susceptibility of seagrasses to anthropogenic impacts and recent declines motivate the need to better understand the drivers of seagrass and the water quality consequences that occur with variation in seagrass abundance. To meet this need, we leveraged existing monitoring data (water quality and seagrass), hydrodynamic circulation model, and biogeochemical model framework with seagrass submodel, to produce a biophysical model of Coos Bay estuary, Oregon, U.S. The model includes biogeochemical processes involving water quality, plankton, seagrass, and sediment-water interactions. Ecosystem models like this are useful for evaluating complex estuarine systems because they allow us to extend our understanding of system dynamics beyond existing observations and perform experiments to identify the processes driving observed patterns. We used the biophysical model of Coos Bay to evaluate the dynamics of water quality and native eelgrass (Zostera marina) under three eelgrass abundance scenarios (zero eelgrass, current extent, and maximum observed extent) to elucidate the relationship between eelgrass and OAH. Including eelgrass in the Coos Bay model produced results that more closely resembled water quality observations – dissolved oxygen (DO) and pH were more dynamic in simulations with eelgrass, often having both higher highs and lower lows. While there were some areas of the estuary where DO improved with the addition of eelgrass to the model there was overall a small net increase in harmful DO conditions (based on a salmon physiological threshold). In contrast, ocean acidification conditions, pH and calcium carbonate saturation state for aragonite (Ω), were improved (based on oyster requirements) with the addition of eelgrass – although the magnitude of improvement differed seasonally and spatially. Our new model represents a useful tool – one which accounts for and controls the relevant physical and biogeochemical processes – to evaluate conditions that confer resilience or enhance vulnerability to OAH in an important Pacific Northwest coastal estuary and results can inform the OAH-related dynamics occurring in other eastern boundary current estuaries.
Continue reading ‘Biophysical model of eelgrass and water quality in Coos Bay, OR shows greater mitigation potential for ocean acidification than hypoxia’Revisiting wastewater pH standards: a policy lever for mitigating coastal acidification and enhancing blue carbon
Published 25 June 2025 Science ClosedTags: mitigation, policy, socio-economy
Global ocean acidification driven by atmospheric CO2 uptake is well recognized; however, coastal zones are subject to additional, localized acidification pressures. Among these, the chronic discharge of low pH treated wastewater (often pH 6.0), permitted under many current regulations, represents a significant but often overlooked stressor. This practice introduces highly acidic loads into sensitive nearshore ecosystems that are chemically incompatible with ambient seawater (pH ∼8.1). This perspective argues for reframing effluent pH not only as a pollutant parameter to be bounded but also as a modifiable policy lever. Revising discharge standards to require a minimum effluent pH > 8.0 for marine outfalls offers a novel pathway to mitigate localized coastal acidification. Furthermore, this approach aligns with emerging ocean alkalinity enhancement strategies, potentially enhancing coastal carbon sequestration and offering cobenefits such as reduced metal toxicity. Such a policy shift necessitates technological adaptation but promises significant benefits for coastal resilience and broader ocean sustainability goals.
Continue reading ‘Revisiting wastewater pH standards: a policy lever for mitigating coastal acidification and enhancing blue carbon’Navigating ocean acidification in shellfish aquaculture: stakeholder perspectives of developing strategies in the U.S. Pacific region
Published 23 May 2025 Science ClosedTags: fisheries, mitigation, North Pacific, socio-economy
Highlights
- Aquaculture ocean acidification threat perceptions declined over the last decade.
- Shellfish industry interviews can guide adaptive strategy co-production.
- Native species portfolio diversification met more skepticism than parental priming.
- Enhanced environmental monitoring is a high research priority across respondents
Abstract
The marine shellfish aquaculture industry across the U.S. Pacific region faces escalating ocean acidification and its associated challenges. This study examines industry participant perceptions and experiences regarding ocean acidification, additional threats, and future research needs, finding a notable decrease in perceived concern regarding ocean acidification over the past decade. Through structured interviews, broad industry perspectives are explored regarding current practices and two specific ocean acidification adaptation strategies under development: parental priming and native species portfolio expansion. While parental priming garnered cautious support contingent on scientific validation, perceptions of native species expansion were polarized, driven by skepticism about regulatory barriers, economic viability, and scalability. Enhanced environmental monitoring emerged as the most widely supported adaptation measure, underscoring its importance in addressing multiple stressors in addition to ocean acidification. By considering industry and operation characteristics while examining potential decision-making biases, this study provides unique insights for co-producing relevant adaptation strategies. Additionally, the critical role of collaboration between stakeholders, researchers, and policymakers in fostering resilience is emphasized.
Continue reading ‘Navigating ocean acidification in shellfish aquaculture: stakeholder perspectives of developing strategies in the U.S. Pacific region’Ocean acidification and its consequences upon the environment
Published 9 May 2025 Science ClosedTags: biological response, mitigation, review
Ocean acidification describes the decline in pH of marine environments as the continue to absorb carbon dioxide (CO2). Research over the past ~15 years has reported the levels of ocean acidification forecasted for the end of the century (CO2 ~800-1000 µatm; pH ~7.6-7.7) This process alters the chemical balance of seawater, leading to significant ecological impacts on marine life, particularly those species that rely on calcium carbonate for shell and skeleton formation. This paper explores the causes, mechanisms, and consequences of ocean acidification, as well as its broader implications for marine ecosystems, biodiversity, fisheries, and human societies. It also highlights potential mitigation strategies to address this pressing environmental challenge, the aim of this study is finding a good strategies to decrease the ocean acidification and decreasing the amount of CO2, also suggesting a suitable ways for protection the animals which effected by ocean acidification. Understanding these impacts is crucial to addressing one of the lesser-known but profoundly important aspects of global climate change.
Continue reading ‘Ocean acidification and its consequences upon the environment’Evaluating the impact of ocean acidification on seafood – a global approach
Published 23 April 2025 Science ClosedTags: biological response, crustaceans, echinoderms, fish, fisheries, growth, mitigation, mollusks, mortality, review
The quality of human life and food security are closely linked to the health of the ocean and the many goods and services it provides. However, the ocean is under cumulative stress from various human-driven pressures, leading to eutrophication, deoxygenation, loss of genetic biodiversity, contamination with emerging pollutants (e.g., microplastics and pesticides), and climate change (warming and ocean acidification). The effects of multiple ocean stressors and their interplay on marine life and ecosystems remain poorly understood. This underscores the urgent need for innovative science to resolve the complexity of the interplay of stressors and the resulting impacts. This paper reports findings from the Coordinated Research Project CRP K41018, a five-year program framed by the IAEA. The project was explicitly designed to advance Member States’ understanding of both quantitative and qualitative impacts of ocean acidification on key economically relevant seafood species across different world regions. Furthermore, based on different sensitivity baselines across species, it aimed at exploring adaptation pathways for aquaculture and food industries. As a result, Member States would have improved their comprehension of resilience building in specific local contexts (e.g., types of environments, geographical parameters, human dimension). In this context, it is essential to look for ocean solutions to mitigate adverse impacts on seafood and support adaptation strategies based on nature that can counteract stressors. It is concluded that there is great synergy in planning integrated mitigation and adaptation strategies to multiple stressors in marine ecosystems.
Continue reading ‘Evaluating the impact of ocean acidification on seafood – a global approach’Long-term successional dynamics and response strategies of harmful algal blooms to environmental changes in Tolo Harbour
Published 18 April 2025 Science ClosedTags: biogeochemistry, biological response, BRcommunity, chemistry, community composition, communitymodeling, field, mitigation, modeling, North Pacific, otherprocess, physiology, phytoplankton, policy
Highlights
- Long-term monitoring reveals significant shifts in harmful algal bloom species and toxin dynamics in Tolo Harbour.
- Government actions reduced nutrient levels, but climate change and organic nutrients influenced HABs’ species succession.
- Number of HABs decreased, meanwhile frequency and types of new toxin species emerged, highlighting complex ecological changes.
- Balanced dual nutrient reduction strategies are essential for controlling HABs and restoring coastal ecosystem health.
ABSTRACT
The production and succession of harmful algae blooms (HABs) are attributed more to excessive nutrient concentrations and unbalanced nutrient stoichiometry than to other environmental drivers as the absence of long-term monitoring data. This study analyzed HABs succession patterns and key drivers in Tolo Harbour from 1986 to 2023, leveraging nearly 40 years of data. Effective governmental measures significantly improved water quality, with dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), 5-day biochemical oxygen demand (BOD5), and Escherichia coli (E. coli) concentrations decreasing by 53%, 80%, 45%, and 59%, respectively. Annual HABs events dropped from 28 to 3, and species diversity declined from 6 to 2. However, toxic species frequency rose from 21% to 46%. Dinoflagellates emerged as dominant initial species, with a shift in secondary dominance from diatoms to ochrophytes and toxin types from diarrhetic shellfish poisoning (DSP) to hemolytic toxins (HT). These shifts likely result from combined human and natural influences. Model simulations confirmed that red tide outbreaks, species succession, and shifts in toxin types were driven by declining pH, rising temperatures, unbalanced nitrogen-phosphorus ratios, organic nutrient increases, and algal antagonism. The study emphasizes the importance of the dual reduction of both DIN and DIP, meanwhile inorganic and organic nutrients, suggesting that overly focusing on or distract from one nutrient (e.g., DIP or DON) could lead to unintended ecological consequences, like the proliferation of rare and toxic species. We highlight the combined impacts of climate change (warming and ocean acidification) and anthropogenic activities (nutrient pollution and eutrophication) on HABs, particularly the number and toxin production. This research links policy changes to HAB dynamics, offering strategic recommendations for managing red tides and contribute novel perspectives on the impact of nutrient reduction in comparable bay ecosystems.
Continue reading ‘Long-term successional dynamics and response strategies of harmful algal blooms to environmental changes in Tolo Harbour’Chapter 6 – Ocean warming, acidification, plastic pollution, and water quality deterioration: a multifaceted crisis unveiled
Published 2 April 2025 Science ClosedTags: mitigation, review
The Earth’s oceans, vast and enigmatic, have long captivated human imaginations with their depths teeming with life. Since the Industrial Revolution, anthropogenic impacts on natural systems have constantly intensified, especially on marine systems. Although most stressors have an anthropogenic origin and occur worldwide, they present different characteristics on which they may be managed. Yet, beneath ocean surfaces lies a profound and intricate crisis – a convergence of challenges that threaten all biological realms and associated marine and coastal environments. This chapter embarks on the intensities and effects of ocean warming, acidification, and plastic pollution-induced water quality deterioration, revealing their interconnectedness and underscoring the urgency of our response. Due to increasing atmospheric CO2, the world’s oceans are warming and slowly becoming more acidic (ocean acidification), and profound changes in marine ecosystems are certain. Calcification is one of the primary targets for studies of the impact of CO2-driven climate change in the oceans. Plastic pollution is ubiquitous in the ocean but causes the most serious harm near coastlines and during its journey toward open waters. The formation of oxygen-depleted dead zones and toxic algal blooms narrate the threats of a compromised aquatic realm due to ocean water quality deterioration. Managing waste and litter streams better, eliminating unnecessary products, ensuring adequate waste management systems are in place, setting up a circular economy for plastic products and waste where possible, boosting recycling, and incinerating unrecyclable plastic waste for energy in conjunction with the development of carbon capture and storage technology help balancing the trade-off with greenhouse gas emissions. Ocean-based renewable energy sources like wave and tidal power can reduce greenhouse gas emissions, combating ocean warming. Carbon capture and storage systems can alleviate acidification by capturing CO 2 emissions from various sources. Advanced waste-removal technologies, including ocean cleanup vessels and AI-powered monitoring systems, aid in tackling plastic pollution. More stress ecology research is needed at the frontier between ecotoxicology and ecology, going beyond standardized tests using model marine species to address multiple water quality factors (pH, temperature, toxicants, etc.) and organisms’ health. These technologies, combined with global collaborations, blue economic strategies, and building awareness, can play a pivotal role in preserving the health and sustainability of Earth’s oceans.
Continue reading ‘Chapter 6 – Ocean warming, acidification, plastic pollution, and water quality deterioration: a multifaceted crisis unveiled’Ocean acidification: understanding the effects, exploring the solutions
Published 4 March 2025 Science ClosedTags: adaptation, biological response, mitigation, otherprocess, review
Human-induced climate change is now a proven fact, no longer in doubt in the scientific community. Heat waves, droughts and floods, storms and hurricanes of unprecedented power are current manifestations of this ongoing climate change, where exceptional events are becoming more and more frequent. The increasing combustion of fossil fuels such as coal, gas and oil, as well as deforestation for agriculture and urbanisation, are enlarging the concentration of greenhouse gases in the atmosphere, warming the planet. Of the greenhouse gases produced by this combustion, carbon dioxide (CO2) is by far the most abundant.
Climate change is not the only consequence of rising atmospheric CO2 concentrations. Anthropogenic CO2 is also partly absorbed by the oceans, where it is transformed into carbonic acid, causing “ocean acidification”. This phenomenon really emerged in the scientific literature in the early 2000s, becoming one of the most studied topics in marine science over the last twenty years. Through its effects on water chemistry, ocean acidification has multiple consequences for the marine world and its inhabitants, and consequently for the biological resources on which we depend to live. However, ocean acidification, often referred to as “the other CO2 problem” in reference to global warming, remains largely unknown to the general public. The few times the media mention this phenomenon, it is to ask whether we will still be eating oysters in 2100! While this question is relevant, as it suggests that these animals are sensitive to acidification, it deserves to be considerably broadened. In other words, the idea is to understand not only the world we live from, but also the world we live in, so that we can face the new climate regime with lucidity and pragmatism.
The aim of this book is to take a comprehensive look at ocean acidification by answering ten simple questions. It reviews the biogeochemical foundations of acidification; past, current and future trends; impacts on organisms, marine ecosystems and humans; and finally, remediation options and scientific perspectives.
The problem of ocean acidification is transdisciplinary, and finds its answers in biogeochemistry, marine biology and ecology, evolution, aquaculture and fisheries, as well as economics and sociology. May this book make accessible to as many people as possible the magnitude of this little-known phenomenon, which is nonetheless essential to understanding future changes.
Continue reading ‘Ocean acidification: understanding the effects, exploring the solutions’Using taxonomy to strengthen aquaculture for climate change, ocean acidification and invasive species
Published 28 February 2025 Science ClosedTags: fisheries, mitigation
The Government aimed to quintuple aquaculture production within 16 years, targeting a NZD 3 billion industry. However, challenges—such as Climate Change, Ocean Acidification and threats from pests—pose hurdles that cannot be overcome by the aquaculture sector alone. Robust collaboration between scientists and the industry is imperative to address these threats and ensure success. Climate Change and Ocean Acidification disrupt the reproduction and settlement of crops, hindering shell growth and increasing the risks of pest attacks. The projected annual cost of mitigating pest species will exceed NZD 150 million. While this figure has been economically evaluated, it does not account for the additional intensification from Ocean Acidification and Climate Change. Each of these factors, alone and in combination, poses a risk of collapse for farms. Collaboration between the industry and scientists is essential for developing solutions and advancing aquaculture practices. Establishing a balanced partnership is crucial for advancing New Zealand’s aquaculture sector, ensuring sustainability and resilience against challenges. Although this perspective is based on taxonomy, developmental biology and shellfish aquaculture, the challenges and insights are applicable across various sectors. Therefore, the obstacles and solutions described are relevant to the tasks and hurdles faced by scientists in other fields.
Continue reading ‘Using taxonomy to strengthen aquaculture for climate change, ocean acidification and invasive species’Future actions for the ocean acidification research community to support marine industries and coastal communities of Aotearoa New Zealand
Published 12 February 2025 Science ClosedTags: fisheries, mitigation, policy
Increasing atmospheric CO2 emissions are altering the carbonate chemistry of seawater in a process known as ocean acidification (OA). This is a growing issue for marine industries and communities. During the 2023 New Zealand Ocean Acidification Community (NZOAC) Conference, the community undertook a horizon scanning exercise to determine potential future activities and opportunities. Conference participants were sent questions that focussed on topics of importance to the Aotearoa New Zealand and global OA community. Sixteen potential actions were identified. During the conference, participants voted for actions they perceived to be most important to give each an overall priority score. In order, the five top priority actions were to (i) re-engage with policymakers to ensure OA is included in policies around climate change, oceans, fisheries, and education; (ii) focus on solutions during engagement actions; (iii) maintain funding for current observation platforms; (iv) engage more with the public through community/public participatory science; and (v) obtain funding for new OA focused research. We summarise the activities identified to address these actions and discuss potential ways forward for the NZOAC and wider research community to undertake the required research and provide much needed guidance to underpin OA mitigation and adaptation efforts.
Continue reading ‘Future actions for the ocean acidification research community to support marine industries and coastal communities of Aotearoa New Zealand’The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes (update)
Published 11 February 2025 Science ClosedTags: biogeochemistry, chemistry, dissolution, mitigation, modeling, regionalmodeling, sediment
Coastal sediments are hotspots of biogeochemical processes that are impacting subsurface and overlying water conditions. Fluid composition in sediments is altered through the mineralization of organic matter which, under oxic conditions, further lowers both pH and the carbonate saturation state. As a potential mitigation strategy for this sediment acidification, we explored the effects of mineral additions to coastal sediments. We experimentally quantified carbonate mineral dissolution kinetics of carbonate shells suitable for field application and then integrated these data into a reactive transport model that represents early diagenetic cycling of C, O, N, S, and Fe and traces total alkalinity, pH, and saturation state of CaCO3. Model simulations were carried out to delineate the impact of mineral type and amount added, porewater mixing, and organic matter mineralization rates on sediment alkalinity and its flux to the overlying water. Model results showed that the added minerals undergo initial rapid dissolution and generate saturated conditions demonstrating the potential of alkalinity enhancement in mitigating surface sediment acidification. Aragonite dissolution led to higher total alkalinity concentrations than calcite. Simulations of carbonate mineral additions to sediment environments with low rates of organic matter mineralization exhibited a substantial increase in mineral saturation state compared to sediments with high CO2 production rates, highlighting the environment-specific extent of the effect of mineral addition. Our work indicates that carbonate additions have the potential to effectively buffer surficial sediments over multiple years, yielding biogeochemical conditions that counteract the detrimental effect of low-pH sediment conditions on larval recruitment and potentially increase benthic alkalinity fluxes to support marine carbon dioxide removal (mCDR) in the overlying water.
Continue reading ‘The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes (update)’
