The dynamics of calcium carbonate structures in marine organisms (skeletons and shells) has become increasingly important due to heightened interest in marine environmental acidification. Research into molluscan shell corrosion and calcification in response to acidification is typically carried out in laboratory-controlled settings, which often overlooks the intricate interactions found in natural environments. Mollusks inhabiting intertidal zones are especially susceptible to intense shell weathering caused by tidal cycles of heating, cooling, wetting, and drying, exacerbated by solar radiation during periods of air exposure. We investigated the effect of sun exposure (solar radiative heating) on both outer shell corrosion and inner shell compensatory calcification in the tropical oyster, Saccostrea scyphophilla. Shell properties were compared between oysters from neighboring populations in sun-exposed and shaded habitats. Habitat temperatures were measured using iButtons, and right shell valve corrosion was quantified. Compensatory calcification was assessed through measurements of shell thickness, shell density, shell compression strength, and mineralogical properties. Our results revealed that oysters in the sun that experience global irradiance, higher temperature peaks and broader daily temperature ranges (averaging an increase of 10 °C) show considerably greater outer shell surface corrosion (87%) compared to shaded oysters (31%) that experience only diffuse irradiance. Sun-exposed shells also become thickened in the midsection and around the adductor muscle, and they are slightly stronger, indicating compensation for the outer shell loss. These findings highlight the need for caution when interpreting molluscan shell dynamics based on laboratory marine acidification protocols that fail to account for the many natural environmental factors influencing shell formation and dissolution.
Continue reading ‘Strong effects of sun exposure on oyster shell corrosion and compensatory calcification: a factor confounding coastal acidification responses’Strong effects of sun exposure on oyster shell corrosion and compensatory calcification: a factor confounding coastal acidification responses
Published 13 July 2026 Science Leave a CommentImpacts of warming, acidification, and deoxygenation on embryos and larvae of gilthead seabream (Sparus aurata)
Published 13 July 2026 Science Leave a CommentSimple Summary
This study evaluated how the combination of ocean warming, acidification, and deoxygenation (“deadly trio”) affects the early development of the fish Sparus aurata. Embryos and recently hatched larvae were exposed to increased temperature (Δ + 4 °C; 22 °C), elevated CO2 levels (pCO2 ~1000 μatm, Δ − 0.4 units; pH 7.7), and reduced oxygen (Δ − 60% O2 saturation; 3 mg O2 L −1). Deoxygenation emerged as the primary stressor, significantly reducing hatching rates, larval survival, and heart rates. These effects were further intensified when combined with warming and acidification. Acidification alone also reduced larval phototactic behavior by 50%, while exposure to all three stressors eliminated phototactic responses entirely. Overall, the results demonstrate that multiple climate-related stressors together severely harm fish early life stages, emphasizing the need to study combined environmental changes to better predict future impacts of climate change on marine fish populations and ecosystem functioning.
Abstract
The interaction between increased dissolved carbon dioxide, rising temperatures, and oxygen loss—the so-called “deadly trio”—is expected to strongly affect marine biota over the coming years, undermining ocean services and uses. Nonetheless, no study has so far scrutinized the cumulative impact of these three stressors on fish embryos and larvae. To fill this knowledge gap, we conducted a fully multi-factorial experiment to investigate the effects of warming (+4 °C: 22 °C), acidification (Δ − 0.4 pH units: 7.7 pH, pCO2 ~1000 μatm), and deoxygenation (Δ − 60% O2 saturation: 3 mg O2 L−1) on physiological and behavioral responses of the commercially important species Sparus aurata. Deoxygenation was the primary factor reducing hatching rates (64.25%), survival (46.71%), and heart rates (31.99%) of recently hatched larvae, being generally further exacerbated when combined with warming and acidification. No larvae exposed to the interaction of the three treatments reacted to the phototactic behavior test. However, acidification alone caused a 50% reduction in phototactic behavior. Our findings demonstrate that the deadly trio is detrimental to early fish development, impacting several key features at this critical life stage, and the need to assess the impacts of stressors’ interaction on marine taxa to better predict future ecosystem responses to ocean changes.
Continue reading ‘Impacts of warming, acidification, and deoxygenation on embryos and larvae of gilthead seabream (Sparus aurata)’TRACE-Python: tracer-based rapid anthropogenic carbon estimation implemented in Python (version 1.0)
Published 13 July 2026 Science Leave a CommentAn implementation of Tracer-based Rapid Anthropogenic Carbon Estimation (TRACE), an algorithm for estimating anthropogenic carbon in the ocean, was produced using the Python coding language. TRACE is a transit time distribution approach intended to increase the accessibility of reliable and accurate anthropogenic carbon estimates. This algorithm produces estimates of ocean anthropogenic carbon as a function of user-supplied coordinates, time, seawater salinity, atmospheric carbon dioxide pathway, and optionally seawater temperature. We demonstrate the identical results of this implementation relative to its MATLAB predecessor, explore the sensitivity of anthropogenic carbon estimates to a newly-expanded range of available user input parameters, and suggest further lines of development for this software product as well as transient tracer-based ocean state estimation in general. Additionally, a new column integration routine was developed and deployed on anthropogenic carbon estimates generated from TRACE-Python when applied to the GLODAPv2.2016b gridded product temperature and salinity, yielding updated global and regional anthropogenic carbon inventories for the industrial era through the year 2500 along a range of atmospheric carbon dioxide trajectories. These inventories demonstrate satisfactory agreement with previous observation-based anthropogenic carbon inventories within the uncertainty of the estimate, demonstrating the skill of the TRACE method at the global level. This implementation of TRACE represents a step forward in accessibility to a wider user base, flexibility in user-specification of a greater number of estimation parameters, and skill as measured against other anthropogenic carbon estimates.
Continue reading ‘TRACE-Python: tracer-based rapid anthropogenic carbon estimation implemented in Python (version 1.0)’Jamaica signs on to four international environmental agreements
Published 13 July 2026 Media coverage Leave a Comment
Minister of Water, Environment and Climate Change, Hon. Matthew Samuda, provides details about the outcomes of the 11th Our Ocean Conference held in Mombasa, Kenya, during a Post-Cabinet Press Briefing at Jamaica House on Wednesday (June 24). Photo: Adrian Walker.
Jamaica signed on to four key international environmental partnerships during the 11th Our Ocean Conference in Mombasa, Kenya, held from June 16 to 18.
The agreements are the Caribbean Ocean Coordination Mechanism, the Ocean Acidification Alliance, the Action in Blue Regional Network, and the Mangrove Breakthrough.
Minister of Water, Environment and Climate Change, Hon. Matthew Samuda, provided the details during Wednesday’s (June 24) Post-Cabinet Press Briefing at Jamaica House.
He explained that the Caribbean Ocean Coordination Mechanism is a platform that “shares the burden of environmental management of our shared Caribbean Sea”.
Anchored by the United Nations Environment Programme (UNEP), the mechanism places Jamaica in a leadership position to manage many of the issues that face Caribbean nations, he pointed out.
As it relates to Ocean Acidification Alliance, he explained that it is a network of scientists who are “specifically focused on the issue of ocean acidification, which is critical to the health of our coral reefs, fisheries and, indeed, to tourism”.
The nation also joined the Action in Blue Regional Network, which is focused on coordinating the protection of 30 per cent of the Caribbean Sea.
“That is something that Jamaica would have lobbied for from as far back as 2015, when Jamaica joined what is called the High Ambition Coalition for Nature, which led the way in calling for 30 per cent protection of our marine environment,” the Minister stated.
Meanwhile, through the Mangrove Breakthrough, which is managed by an alliance chaired by Colombia and Jamaica, the country will be working with partner nations and institutions to strengthen efforts on mangrove protection and restoration.
The Minister noted that Jamaica needs support in protecting its mangroves, especially along the south coast “where we are exposed to heavy storm surge in times of storms and have low coastal defences”.
Meanwhile, the Minister noted that while in Kenya, he had a bilateral meeting with the Green Climate Fund, which is also currently in Jamaica for a technical mission.
“While there, it was announced that Jamaica was approved for an additional US$2.1-million grant being managed by the CCCCC (Caribbean Community Climate Change Centre), which is the CARICOM unit that manages climate change, to assist Jamaica with getting projects ready for submission for significant grant funding,” Mr. Samuda shared.
The grant is titled ‘Catalysing Climate Action by building Jamaica’s NDA Capacity & Country Investment Platform’.
CARICOM has indicated that it will help Jamaica access international climate financing and develop a pipeline of projects needed to protect its people, economy and environment.
Continue reading ‘Jamaica signs on to four international environmental agreements’The effects of single and multiple climate-driven stressors exposures on the seagrass Posidonia oceanica: phenological, cellular, and genetic adaptations
Published 10 July 2026 Science Leave a CommentTags: adaptation, biological response, Mediterranean, phanerogams
Posidonia oceanica is a foundation seagrass species endemic to the Mediterranean Sea, where it forms highly productive meadows that support biodiversity, coastal protection and long-term blue carbon storage. However, these ecosystems are increasingly threatened by the combined effects of climate change and local anthropogenic pressures, including ocean warming, marine heatwaves, ocean acidification, hypersalinity and thermal pollution. Despite growing evidence of the vulnerability of P. oceanica to environmental change, the mechanisms underlying its acclimation capacity, resilience and potential vulnerability thresholds remain only partially understood, particularly under multiple-stressor scenarios.This study investigates the responses of P. oceanica to climate change-related stressors across multiple levels of biological organization, integrating evidence from meta-analysis, controlled mesocosm experiments, molecular analyses and field observations. Special attention is given to the role of environmental history in shaping population-specific responses, comparing plants exposed to contrasting environmental conditions and assessing their phenological, physiological, metabolic and molecular performance under single and combined stressors.By linking organismal, molecular and meadow-scale responses, this work provides new insights into the capacity of P. oceanica to cope with future climate scenarios and local anthropogenic disturbances. The findings contribute to identifying resilience mechanisms and vulnerability patterns in Mediterranean seagrass ecosystems, supporting the development of more effective monitoring, management and conservation strategies under ongoing global change.
Continue reading ‘The effects of single and multiple climate-driven stressors exposures on the seagrass Posidonia oceanica: phenological, cellular, and genetic adaptations’Coastal Ocean Data Analysis Product in North America (CODAP-NA, Version 2026) from 1981-08-23 to 2024-11-23 (NCEI Accession 0315529)
Published 10 July 2026 Science Leave a CommentTags: chemistry
The coastal Ocean Data Analysis Product in North America (CODAP-NA) Version 2026 represents a major expansion of coastal ocean carbonate chemistry synthesis for North American continental margins. Compared to CODAP-NA Version 2021 (61 cruises, 3,391 profiles, and 28,206 data rows), the updated product integrates newly available cruise observations spanning more than four decades, substantially increasing both the spatial and temporal coverage of coastal biogeochemical measurements across all North American continental shelves. This version of the CODAP-NA is composed of 32,250 oceanographic profiles from 446 research cruises covering all continental shelves in North America (U.S. west coast, U.S. east coast, Gulf of Mexico, and Alaska coast). Data for 14 variables (temperature; salinity; dissolved oxygen concentration; dissolved inorganic carbon concentration; total alkalinity; pH on the Total Scale; carbonate ion concentration; fugacity of carbon dioxide; and concentrations of silicate, phosphate, nitrate, nitrite, nitrate plus nitrite, and ammonium) have been subjected to extensive quality control. Funding for this work comes from the National Oceanic and Atmospheric Administration (NOAA) Ocean Acidification Program.
Continue reading ‘Coastal Ocean Data Analysis Product in North America (CODAP-NA, Version 2026) from 1981-08-23 to 2024-11-23 (NCEI Accession 0315529)’Global governance failing to address growing threat of ocean acidification to food security, new study warns
Published 10 July 2026 Press releases Leave a CommentInternational institutions managing fisheries and climate change operate in silos, leaving a critical gap in protection for communities dependent on blue foods.
London, 18th June 2026 – A new study, launched during Our Oceans Conference being held in Mombasa, finds that international governance frameworks are poorly equipped to address the combined threat of ocean acidification (OA) and blue food insecurity — despite both issues becoming increasingly urgent for global sustainability. The research, published in Environmental Research: Food Systems, maps the international governance landscape for both issues and finds that, while the two policy domains overlap significantly, they are rarely addressed together.
Annika Frosch, lead author and Research Fellow at the UCL Energy Institute Shipping and Oceans Research Group, said: “Without coordinated action across climate and food systems, the growing impacts of ocean acidification will continue to undermine fisheries and aquaculture that underpin global nutrition and livelihoods.”
The thematic nodes represent issue areas related to blue food security (blue) and ocean acidification (green). The nodes in the centre are those that apply to both blue food security and ocean acidification, and issues that were identified as critical governance areas at the OA-blue food nexus. The fisheries, aquaculture, and climate change nodes represented in red are discussed further in the paper.
Blue foods — fish, shellfish, and algae sourced from marine and freshwater environments — provide essential nutrients to millions of people worldwide, and global consumption has grown more than fivefold over the past 60 years. At the same time, ocean acidification, driven primarily by rising CO₂ emissions, is already harming shellfish aquaculture and fisheries, degrading coral reef ecosystems, and altering the nutritional quality and safety of seafood. Communities in the Global South, which rely most heavily on blue foods for daily protein, face the greatest risks — yet also receive the least research attention and policy support.
Using a structured review of international governance literature and a thematic mapping exercise, the researchers identified thirteen policy domains relevant to blue food security and ten relevant to ocean acidification, seven of which overlap — including fisheries and aquaculture, biodiversity, climate change, and land-based pollution.
Despite this overlap, the study finds that most international actors and instruments treat the two issues in isolation. A detailed examination of two central institutions — the Food and Agriculture Organization (FAO) and the UN Framework Convention on Climate Change (UNFCCC) — illustrates the problem clearly:
- The FAO lacks an explicit mandate to govern ocean acidification. When OA is mentioned in FAO instruments, it typically appears as one item in a longer list of climate stressors, rather than being treated as a distinct and direct threat to food security.
- The UNFCCC addresses ocean acidification only indirectly, through its broader CO₂ mitigation goals. Neither the UNFCCC nor the Paris Agreement explicitly names OA, and it does not feature as a core governance priority. Food security is referenced in UNFCCC objectives but is not linked to OA even in documents that mention both.
The study also highlights a troubling asymmetry: blue food security tends to receive legal and political recognition, while ocean acidification remains largely confined to scientific discussion — making coordinated policy action harder to achieve.
Keiko Nomura, co-author and Postdoctoral Researcher at the University of Colorado Boulder, said “Our findings suggest that ocean acidification remains more visible in scientific discussions than in international policy frameworks. Bridging this science-policy divide could help improve governance of climate risks to blue food systems.”
The paper makes recommendations for policy makers to bridge these governance gaps, including:
- Strengthening FAO instruments to treat OA as a distinct climate-related stressor to fisheries and aquaculture, including through binding policies, vulnerability thresholds for key species, and the promotion of socioeconomic strategies.
- Developing a dedicated OA workstream or technical body under the UNFCCC
- Incentivising countries to include OA monitoring and adaptation measures in their Nationally Determined Contributions (NDCs)
- Creating formal institutional links and coordination between climate bodies and marine science and fisheries organisations modelled on the Joint Capacity-building Programme of the three ‘Rio Conventions’, adapted for the OA–blue food security nexus
Inken Dressler, co-author and European Programme Lead at the International Alliance to Combat Ocean Acidification (OA Alliance): “The siloed recognition and approach to ocean acidification and blue food security hinders effective governance of both issues. To bridge this gap, closer cooperation between existing frameworks such as the UNFCCC and FAO must be achieved.”
The researchers note that some Pacific Island nations — including Fiji and the Solomon Islands — are already leading the way by integrating ocean acidification into their national climate strategies and fisheries management plans, demonstrating what more coherent governance could look like.
The study accompanies Dr Frosch’s new book ‘Navigating the Souring Seas: The Global Experimentalist Governance of Ocean Acidification’ which explores how OA is being addressed at the global stage. Bridging science, law, and international policy, this interdisciplinary book provides a clear overview of the scientific background of OA and maps the international governance landscape, identifying it as a regime complex. Through detailed interview-based case studies of the Ocean Acidification Alliance and the International Maritime Organization, the book evaluates real-world efforts to govern OA and highlights how flexibility, learning, and multilevel collaboration, can enhance their effectiveness.
Continue reading ‘Global governance failing to address growing threat of ocean acidification to food security, new study warns’Job opportunity: Ocean acidification education intern (WRM-2026-5i)
Published 9 July 2026 Jobs Leave a CommentOpen to: General Public
Work Week: Up to 35 hours per week (5 days per week)
Hourly Rate: Sliding Scale based on Education Level ($19-$24 Per Hour)
Opening Date: 7/1/2026
Closing Date: 7/22/2026
Existing Vacancies: 1
Internship Length: 9/21/2026 – 12/11/2026
Program/Location:
Department of Environmental Protection
Water Resource Management
Division of Water Monitoring, Standards, and Pesticide Control
Bureau of Environmental Analysis and Restoration
401 East State Street
Trenton, NJ 08625
Program Description: The WRM Program establishes water quality and drinking water standards, monitors the waters of the State to ensure surface and groundwater standards are met, helps ensure delivery of water that meets drinking water standards, and regulates discharges of wastewater and storm water to surface and ground water. The WRM Program also regulates and manages the diversion of water from surface and groundwaters to ensure protection of the resources and provides low cost financial assistance for finance capital improvements to water infrastructure. The Program works to ensure adequate, reliable, sustainable supplies for current and future needs, uses, and the environment.
Project Description: NJ’s shellfish and fisheries are expected to be impacted by ocean acidification due to atmospheric CO2 emissions. NJ’s coastal waters are monitored for pH and dissolved oxygen to understand ecological impact and ecosystem stress. The Bureau of Environmental Analysis and Restoration is part of the DEP’s Ocean Acidification Workgroup tasked with monitoring, research, and education. The Spark Intern project would enable the DEP to meet its mission to protect water resources and educate the public on this issue. AmeriCorps NJ Watershed Ambassadors will pilot the materials developed.
Specific to the Position: The intern will be tasked with developing educational materials that explain ocean acidification to the K-12 audience.
Preferred Area of Study: Seeking individuals enrolled at an accredited university/college studying one of the Physical Sciences, Environmental Sciences/Studies, Chemical Sciences, Biological Sciences, or in Environmental Planning, Environmental Policy, or Physical Geography; or in Civil Engineering, Sanitary Engineering, Chemical Engineering, Environmental Engineering, Mechanical Engineering, Agricultural Engineering, Mining Engineering, Industrial Engineering, or Bio-resource Engineering.
License: Appointee will be required to possess a driver’s license valid in New Jersey only if the operation of a vehicle, rather than employee mobility, is necessary to perform the essential duties of the position.
Employee Benefits
TES / Hourly employee benefits include:
- Earned Sick Time*
*Pursuant to the State/Department’s policy, procedures, and/or guidelines.
SAME applicants: If you are applying under the NJ SAME program, your supporting documents (Schedule A or B letter) must be submitted along with your resume by the closing date indicated above. For more information on the SAME program, please email SAME@csc.nj.gov, or call CSC at (609) 292- 4144 and select Option #3.
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Continue reading ‘Job opportunity: Ocean acidification education intern (WRM-2026-5i)’Impact of climate change on Portuguese marine coastal environments
Published 9 July 2026 Science Leave a CommentTags: chemistry, modeling, regionalmodeling, review
The potential impacts of climate change on marine habitats were assessed using RCP4.5 and RCP8.5 projections of environmental parameters that included sea surface temperature (SST), pH, salinity, planktonic productivity (PP) and current strength (CS). The analysis was conducted separately for three distinct oceanographic regions of the Portuguese coastline (North, Centre and South) up to the middle of the century. Temporal trends in environmental variables were assessed using time series analyses. Overall, changes expected up to the middle of the century include increasing SST and PP, decreasing pH and salinity, and slight increases in CS. Spatial–temporal analyses revealed high present–future environmental overlay for most environmental variables. However, changes in individual environmental variables cumulatively resulted in statistically significant changes in environmental similarity. Still, the projected changes are not expected to exceed ecological thresholds, above which they would be likely to alter species’ habitat suitability or to result in species distribution shifts. Anomaly analyses suggest that present–future shifts do not surpass 1/5 (pH, PP, CS) or 2/3 (salinity) of the unit, regardless of projection and area, while SST anomalies ranged from −1.1 °C to 1.1 °C. Compared to IPCC large-scale predictions for Atlantic/Mediterranean regions, the intensity of shifts on the Portuguese coast may be lower.
Continue reading ‘Impact of climate change on Portuguese marine coastal environments’Climate assessment report for the Central Arctic Ocean (CAO) [Suppl. to ICES Scientific Reports 8(25)]
Published 9 July 2026 Science Leave a CommentTags: Arctic, chemistry, community composition, fish, mammals, zooplankton
Climate change is transforming the Central Arctic Ocean (CAO) at an unprecedented pace. Sea ice is rapidly declining in extent, thickness, and age, with projections indicating an ice-free summer Arctic by mid-century, possibly earlier. This loss of ice amplifies warming, alters stratification and circulation, and accelerates ocean acidification—occurring up to four times faster than the global average—threatening calcifying organisms and ecosystem stability.
Biological impacts are profound: shifts in microbial and primary producer communities, reduced ice-associated biodiversity, and boreal species moving northward disrupt food webs. Benthic ecosystems show signs of long-term decline in biodiversity and organic carbon supply, while fish, seabirds, and marine mammals face habitat loss, changing prey availability, and new stressors such as increased predation and contaminants. Some species may benefit from enhanced productivity, but cumulative effects of warming, acidification, and ice loss remain uncertain. These changes interact with other pressures—pollution, invasive species, and human activities—creating complex, compounding stress on the CAO ecosystem. Knowledge gaps on tipping points and resilience underscore the urgent need for research on circulation, carbon dynamics, and species adaptation to inform conservation and management strategies.
Continue reading ‘Climate assessment report for the Central Arctic Ocean (CAO) [Suppl. to ICES Scientific Reports 8(25)]’Globally the ocean absorbs about a quarter of the carbon dioxide produced on land. This varies seasonally and by region. We visit the PAP-SO in spring just as the largest plankton bloom is starting, shown by the orange and red colours in the satellite map below. This productivity makes the northeast Atlantic a key region for carbon dioxide uptake into the ocean.
Satellite image of NE Atlantic chlorophyll.
On JC247 we are using several methods to measure this process. The Met Office ODAS buoy carries instruments for year-round measurement of ocean biogeochemistry, including seawater and atmospheric carbon dioxide (Pro-Oceanus). We observe the phytoplankton bloom at PAP-SO with chlorophyll, oxygen and nutrient sensors that we can compare with satellite images. This year we have an exciting addition to our upper ocean measurements – an underwater holographic camera (LISST-Holo) we can use to measure plankton communities in the surface water. All these measurements help us understand drivers of carbon dioxide uptake.
PAP buoy on deck.
During the research cruise we take physical water samples around the PAP-SO, sampling right down to 4850m depth. The water will be analysed in our laboratories on board, and ashore at NOC. We also have a SubCtech ‘flow through’ system on board. It allows us to map surface seawater carbon dioxide in the whole region around PAP-SO. From the summer of this year a similar system will be fitted permanently to the ship to make measurements during other research cruises and during transit, with the benefit of gathering data in under surveyed regions of the world.
All of the carbon dioxide data we collect on JC247 will contribute to the Surface Ocean CO2 Atlas (SOCAT). This global map of carbon dioxide helps in our understanding of climate change and ocean acidification. PAP data also contributes to the Integrated Carbon Observation System which uses key long-running ocean, land and atmospheric greenhouse gas sites across Europe. We are excited that the PAP-SO has been accepted as a ‘labelled ICOS station’ for carbon dioxide measurements from 2023.
Sue Hartman operating our underway CO2 system.
The team on board the RRS James Cook are grateful to the Met Office for use of the ODAS buoy at PAP-SO as well as all of the technicians, scientists and engineers (both onboard and ashore) who have helped instrument the buoy.
Continue reading ‘Measuring carbon dioxide uptake at PAP-SO’Acidification dominates over hypoxia in controlling estuarine nitrogen removal Dynamics under coupled stressors
Published 8 July 2026 Science Leave a CommentTags: North Pacific
As critical transitional zones between land and sea, estuaries are confronting the dual threats of increasing acidification and hypoxia driven by human activities and climate change. However, the combined effects of these stressors on estuarine nitrogen removal processes remain poorly understood. In this study, using stable-isotope tracing and molecular techniques in the Yangtze estuary, we found that hypoxia promoted N removal, yet concurrent acidification can override this effect, leading to net inhibition and a consequent reduction in estuarine nitrogen removal capacity. However, in seasonally hypoxic zones, these combined stressors generally enhanced nitrogen removal rates (by up to 34.4%), which suggests a degree of resilience under such perturbations. Nevertheless, the concurrent acidification–hypoxia in seasonally hypoxic areas stimulated N2O emissions (8.5–44.4%), which may intensify climate forcing and thereby further exacerbate these environmental stressors. Metagenomic and quantitative PCR analyses corroborated these response patterns, revealing coordinated changes in the abundance and expression of key nitrogen-removal genes, as well as divergent microbial response strategies and niche differentiation under acidification–hypoxia stress. This study elucidates the previously overlooked interactive effects of acidification and hypoxia on estuarine nitrogen removal, providing a mechanistic basis for refining biogeochemical models to improve the reliability of simulations under multiple stressors.
Continue reading ‘Acidification dominates over hypoxia in controlling estuarine nitrogen removal Dynamics under coupled stressors’The fate of macroalgal carbon under microbial anaerobic respiration: a critical factor in macroalgae cultivation for climate change mitigation
Published 8 July 2026 Science Leave a CommentTags: algae, biological response, laboratory, mitigation
Highlights
- Anoxic remineralization rates were not consistently lower than oxic rates.
- Macroalgal degradation modulates the DIC pool, crucial for carbon sequestration.
- Alkalinity generated by anaerobic respiration stabilizes the DIC pool.
Abstract
Macroalgae play a significant role in global carbon sequestration. Substantial macroalgal organic carbon inputs and subsequent degradation can cause deoxygenation; however, the impact of oxygen deficiency on carbon fate remains understudied, which is critical for assessing the climate mitigation role of macroalgae. Here, we investigated changes in the carbon pool and non-CO2 greenhouse gases (N2O and CH4) to assess the influence of oxygen levels on the carbon sink capacity of macroalgae. The microbial remineralization rate of macroalgal organic matter was not consistently slower under anoxic conditions (AK) compared to oxic conditions (OK). Total organic carbon (TOC) concentrations in the water column were 530 ± 94 (OK) and 282 ± 38 (AK) μmol kg−1. For dissolved inorganic carbon (DIC), concentrations on day 30 were 4585 ± 197 (OK) and 5200 ± 492 (AK) μmol kg−1, while those for total alkalinity (TA) were 2684 ± 18 (OK) and 4523 ± 671 (AK) μmol kg−1. Following a 30-day sealed incubation, the bags were opened to reach atmospheric equilibrium. Subsequently, DIC dropped to 1837 ± 79 (OK) and 3744 ± 354 (AK) μmol kg−1, and TA fell to 2059 ± 14 (OK) and 4431 ± 657 (AK) μmol kg−1. Ultimately, relative to the control group (seawater only, OS) under air-sea equilibrium, the ΔDIC values were −22 ± 76 and 1885 ± 351 μmol kg−1 in the OK and AK treatments, respectively, while ΔTA values were −57 ± 11 and 2315 ± 655 μmol kg−1. The emissions of N2O and CH4 did not substantially offset the climate effect of carbon sequestration. These results suggest that, beyond the traditional focus on organic carbon preservation, anaerobic respiration under anoxic conditions may also contribute to macroalgal carbon sequestration by generating alkalinity that enhances the retention and stabilization of DIC.
Continue reading ‘The fate of macroalgal carbon under microbial anaerobic respiration: a critical factor in macroalgae cultivation for climate change mitigation’An updated version of the OA-ICC bibliographic database is available online.
The database currently contains 9,902 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, 7 July 2026.
Evaluating the combined effects of ocean acidification and harmful algal blooms on the fitness of Artemia salina
Published 6 July 2026 Science Leave a CommentTags: biological response, crustaceans, mortality, multiple factors, performance, physiology, reproduction, toxicants, zooplankton
This study assessed the potential synergistic effects of harmful algal blooms (HABs) and ocean acidification (OA) on the survival and grazing potential on HABs by brine shrimp (Artemia salina). The effects on the fitness of three life stages (i.e. newly hatched, 1-week old, and 2-week old post hatch) of A. salina was evaluated over a 24-hour period. Using well plates, A. salina were individually exposed to toxin producing HABs (i.e. Alexandrium catenella or Margalefidinium polykrikoides), a non-toxin producing HAB (i.e. Gymnodinium aureolum), and fed or unfed non-HAB controls. pH conditions administered were ambient (pH ~ 8) or acidified (pH ~ 7.2). Survival analysis revealed a significant effect of treatment on mortality across life stages. Hazard ratios showed elevated mortality in HAB treatments relative to controls, while OA alone did not. HAB exposure or ontogeny are more important for survival of A. salina than short-term OA exposure. Regarding grazing potential, significant reductions in HAB cell density were more commonly found in treatments with older individuals than younger conspecifics. Cell density of A. catenella was never significantly reduced as compared with other HAB treatments. Overall, exposure to OA conditions did not affect the survival or grazing potential of A. salina, but the species of HAB did.
Continue reading ‘Evaluating the combined effects of ocean acidification and harmful algal blooms on the fitness of Artemia salina’Reassessing the climate mitigation benefits and environmental risks of coastal seaweed farming
Published 6 July 2026 Science Leave a CommentTags: algae, mitigation, socio-economy
Seaweed farming is increasingly promoted as a nature-based solution for marine carbon dioxide removal (mCDR), offering the dual promise of climate mitigation and ecosystem enhancement. However, here we highlight a fundamental paradox: while macroalgae cultivation can significantly boost carbon sequestration and support biodiversity, it also introduces site-specific ecological risks—most notably eutrophication, hypoxia, and acidification—particularly in semi-enclosed coastal systems with limited water exchange. We synthesize current understanding of both the positive and negative impacts of large-scale macroalgae farming, examining pathways of carbon uptake, storage, and export alongside biogeochemical and food web disruptions. Critically, we identify the overlooked roles of hydrodynamic conditions and benthic-pelagic coupling in mediating ecological outcomes. To ensure that macroalgae aquaculture contributes effectively to climate goals while safeguarding coastal ecosystem resilience, we call for the development of a targeted and comprehensive evaluation framework capable of accurately assessing its impacts on adjacent waters. Such a framework should incorporate site-specific water-exchange characteristics and biogeochemical vulnerability, thereby enabling more informed and adaptive management strategies—including hydrodynamically guided site zoning—to support sustainable, long-term ecosystem benefits.
Continue reading ‘Reassessing the climate mitigation benefits and environmental risks of coastal seaweed farming’Interactive effects of triclosan, microplastic vectors, and ocean warming–acidification on sea urchin embryo development
Published 6 July 2026 Science Leave a CommentTags: biological response, echinoderms, growth, laboratory, morphology, multiple factors, North Atlantic, physiology, plastics, reproduction, toxicants
Highlights
- Microplastics modulate triclosan toxicity in a concentration-dependent manner.
- Microplastic loads reverse triclosan attenuation affecting larval development.
- Acidification amplifies triclosan–microplastic toxicity in sea urchin embryos.
- Ocean Warming modulates toxicity; degree-day normalization reveals hidden stress.
Abstract
Understanding how emerging contaminants interact with climate-driven stressors is essential for accurate ecological risk assessment in coastal ecosystems. This study evaluates the individual and combined effects of triclosan (TC), polyethylene microplastics (MP), ocean warming (OW), and ocean acidification (OA) on the early development of Paracentrotus lividus embryos. A tiered experimental design was implemented to: (i) characterize TC dose–response curves alone and in combination with increasing concentrations of MP (300–3000 particles mL−1), and (ii) assess how OW (24 °C) and OA (pH 7.6) modulate contaminant toxicity. TC showed concentration-dependent growth inhibition, while MP exhibited a biphasic interaction with TC: at moderate concentrations, MP increased EC10 values and steepened dose–response slopes, consistent with contaminant sorption reducing freely dissolved TC. At 3000 particles mL−1, this trend reversed, lowering EC50 values and enhancing toxicity. Morphometric analyses revealed that co-exposure to TC alone and with MP loads impaired arm elongation, increased body-width ratios, and reduced stomach volume, indicating compromised feeding and skeletal development. Climate stressors significantly altered toxicological outcomes. OA strongly amplified the combined toxicity of TC + MP, reducing larval growth to near-zero levels, whereas OW alone did not exacerbate toxicity and partially mitigated OA-driven effects in MP-TC treated groups. Degree-day normalization demonstrated that warming accelerates development but reduces growth efficiency across treatments. Overall, these results reveal threshold-dependent MP–TC interactions and highlight acidification as a critical amplifier of contaminant effects. Incorporating realistic MP–pollutant interactions and climate variables is crucial for improving hazard assessments under future ocean scenarios.
Continue reading ‘Interactive effects of triclosan, microplastic vectors, and ocean warming–acidification on sea urchin embryo development’Study on the mechanical characteristics of the stress relaxation in the carbonate rock after high-temperature acidification
Published 3 July 2026 Science Leave a CommentTags: chemistry, laboratory, modeling, paleo
To elucidate the mechanism by which acidification influences wellbore stability in deep reservoir formations, this study investigates the rheological and mechanical behaviors of the carbonate rock subjected to high-temperature acid etching. A novel experimental system was developed to characterize the stress relaxation behavior of the acid-etched carbonate rock, and the characteristics of the stress relaxation curves under various acid etching conditions and strain levels were systematically analyzed. Combined with Burgers model and the Levenberg–Marquardt algorithm, the evolution of rheological parameters of the carbonate rock under different acid etching regimes was quantitatively evaluated. The results indicate that the acid-etched carbonate rock exhibit significant rheological mechanical properties due to the presence of developed microcracks and complex pore structures. Under the identical acid etching duration and temperature, the initial stress, residual stress, and time required for stress relaxation stabilization all increase with increasing the strain level. Overall, the stress relaxation magnitude prior to the core fracture ranges from 15 to 25 MPa, and the stabilization time for the core stress relaxation falls between 5 and 7 h. The stress relaxation behavior of the acid-etched carbonate core is well described by the Burgers model. At fixed strain levels and temperatures, the instantaneous shear modulus decreases linearly with extended acid etching time, whereas the instantaneous shear modulus and the viscosity coefficients and exhibit exponential degradation. The final variation ranges of the key rheological parameters are determined as follows: instantaneous shear modulus ranges from 5 × 103 to 2 × 104 MPa, instantaneous shear modulus ranges from 6 × 105 to 2 × 106 MPa, viscosity coefficient ranges from 2 × 107 to 8 × 107 MPa h, and viscosity coefficient ranges from 1 × 105 to 1.2 × 106 MPa h. Furthermore, the evolutionary equations correlating the global model fitting parameters with the porosity of acid-etched samples are established, using acid etching time as an intermediate variable. The results of this study provide a theoretical basis for the analysis of wellbore stability after acidification and the selection of acid fracturing completion methods of deep reservoirs.
Continue reading ‘Study on the mechanical characteristics of the stress relaxation in the carbonate rock after high-temperature acidification’Assessing early oil industry awareness of the impacts of fossil fuels on coral reefs using a novel AI agent
Published 3 July 2026 Science Leave a CommentTags: biological response, corals, modeling, review
Global warming threatens to eradicate Earth’s tropical corals. As legal interventions addressing climate change expand, fossil fuel companies’ historical awareness of their products’ damaging effects is increasingly important. We searched historical documents using a large-language-model-based agent, finding that carbon majors were aware by the 1980s of prospective impacts of fossil fuels on corals from ocean acidification, marine heatwaves, sea-level rise, and intensified storms and later funded efforts downplaying such impacts.
Introduction
The world’s tropical coral reefs are under imminent threat of collapse from global warming. Living corals have declined by approximately 50% worldwide since the 1990s, with global warming now the greatest threat to future survival1. Global warming kills corals primarily through increased ocean temperatures and more frequent and intense marine heatwaves, which cause coral bleaching (loss of coral symbionts), exacerbated by ocean acidification (from increased carbon dioxide levels), which weakens coral health, and intensified storms (from increased sea surface temperatures), which physically destroy coral assemblages, all ultimately caused by fossil fuels1. Approximately one billion people worldwide depend directly on coral reefs for livelihoods, food security, and protection from storms and coastal erosion, and coral reefs provide shelter and nourishment to over 30% of the world’s named marine species2. Economically, coral reefs provide an estimated 10 trillion USD per year in ecosystem services, including tens of billions of dollars per year in coral reef tourism3, and potential efforts to restore reefs lost over the last decade alone have been estimated to cost around 1 trillion USD2. Mass coral bleaching and mortality from marine heatwaves driven by global warming is ongoing4. The Intergovernmental Panel on Climate Change (IPCC) predicts mortality of 70—90% of the world’s reef-building corals at global warming of 1.5 °C and mortality of more than 99% at 2 °C1.
Legal interventions may play a critical role in helping to protect the world’s coral reefs and associated ecosystems (for example, by securing funding for reef monitoring and rehabilitation) and in compensating affected communities for economic losses associated with climate-change-driven coral impacts. In this context, the history of fossil fuel industry awareness of the foreseeable impacts of climate change on coral reefs is highly relevant. Climate lawsuits against governments, fossil fuel producers, and other parties have expanded in number and sophistication over the past decade5 and have recently cited impacts on coral reefs6. Additionally, the 2024 and 2025 advisory opinions from the International Tribunal for the Law of the Sea (ITLOS)7 and the International Court of Justice (ICJ)8 on climate change clarified, respectively, that greenhouse gases are marine pollutants under the United Nations Convention on the Law of the Sea (UNCLOS) and that best efforts to attain the 1.5 °C warming limit of the United Nations Framework Convention on Climate Change (UNFCCC) Paris Agreement are legally binding on governments under international law, strengthening the basis for legal actions seeking to mitigate global warming and obtain reparations for damages. Research on the fossil fuel industry’s internal knowledge of global warming9, public-facing denial and minimization of the problem10,11, and false assurances to be solving it12 has clarified global warming as not only a scientific and technological problem but also one of corporate corruption subject to legal correction and remedy13. Such research has so far informed dozens of ongoing legal actions seeking industry accountability for climate change14.
Continue reading ‘Assessing early oil industry awareness of the impacts of fossil fuels on coral reefs using a novel AI agent’Thermal regulation of benthic fluxes in temperate estuaries
Published 2 July 2026 Science Leave a CommentTags: biogeochemistry, laboratory, multiple factors, sediment, temperature
The effects of short-term heatwave extremes on biogeochemical cycling and fluxes in a temperate estuary of a semi-dry climate were studied using an experimental setup of temperature-controlled benthic incubations. The results demonstrated a strong thermal effect, notably under extreme warming events, for shifts in exchanges across the sediment-water interface. Extreme heatwave conditions (+5 °C of the seasonal mean) boosted acidification, hypoxia, and ammonification, due to accelerated remineralization rates, resulting in strong effluxes of NH4, Si(OH)4, and PO4 to the overlying water. These excessive nutrient loads may increase eutrophication risk via runoff or tidal action, specifically in adjacent oligotrophic coastal waters. CO2 production rates reached ~4000 µatm under extreme hypoxia and acidification, 2.3-fold higher than the ambient rate, with a maximal flux of ~27.0 mmol m-2 d-1. Hence, our experiments show that marine heatwaves amplify CO2 emissions while reducing the CO2 buffering capacity of temperate estuaries. It emphasizes temperate estuaries as highly sensitive ecosystems to climate change.
Continue reading ‘Thermal regulation of benthic fluxes in temperate estuaries’
