Ocean warming is driving species range extensions into cooler regions. The direct physiological influence of warming on species performance can accelerate such extensions into novel ecosystems; however, indirect effects of invader–resident interactions in cooler regions may counter these positive effects. Here, we examined the foraging performance and densities of competing warm‐water and cool‐water fishes across a latitudinal temperature gradient spanning 1500 km from tropical to temperate reefs subjected to rapid ocean warming in the southern hemisphere, and across natural analogs of temperate, tropicalized, and acidified reef localities in the northern hemisphere, and during a severe marine heatwave at a temperate reef. While current levels of ocean warming have allowed the warm‐water fish to extend their ranges into temperate ecosystems at both hemispheres, their foraging performance was reduced at both the cold‐ and warm‐temperate reefs compared to the (sub)tropical reefs. However, at the (warmer) tropicalized reef, the warm‐water fish had higher foraging performance and maintained densities, even under extreme pH reduction, compared to the temperate reef. In contrast, the cool‐water species struggled at the warmer tropicalized and extreme reefs with reduced foraging performance and lower population densities compared to the temperate reef. Contrastingly, the severe heatwave experienced at the temperate reef did not alter the foraging behaviors of either species. We suggest that ocean warming boosts the foraging performance of the range‐extending warm‐water fish and impairs that of their cool‐water competitor at temperate reefs, irrespective of acidification and heatwaves, leading to a shift in dominance hierarchies on temperate reefs. We conclude that warming‐driven increases in foraging performance of the warm‐water species may alleviate foraging limitations and enhance its establishment at its leading range edges under climate change, to the detriment of its cool‐water competitors.
Continue reading ‘Range-extending fish become competitive dominants under ocean warming but not heatwaves or acidification’Range-extending fish become competitive dominants under ocean warming but not heatwaves or acidification
Published 27 February 2026 Science Leave a CommentTags: biological response, field, fish, multiple factors, North Pacific, performance, temperature, vents
The invisible engine of the oceans: marine microorganisms driving climate resilience and ecosystem stability: a literature review
Published 27 February 2026 Science Leave a CommentTags: biological response, community composition, otherprocess, physiology, review
Marine microorganisms form the invisible foundation upon which ocean life depends. Despite their microscopic size, they regulate major biogeochemical cycles, sustain primary productivity, and play a decisive role in maintaining the balance and resilience of marine ecosystems. As climate change intensifies and marine pollution expands in scale and complexity, the responses of these microbial communities have become central to understanding the future of the oceans. This work explores the diversity of marine microorganisms and examines how rising sea temperatures, ocean acidification, physical oceanographic changes, and multiple pollution sources interact to reshape microbial structure and function. Current evidence shows that shifts in temperature and seawater chemistry can alter microbial metabolism, community composition, and ecological interactions, with far-reaching consequences for carbon cycling, nutrient availability, and food web dynamics. At the same time, chemical pollutants, plastics, heavy metals, and excess nutrients impose strong selective pressures, often disrupting microbial balance while also promoting the emergence of microorganisms capable of degrading contaminants. These dual responses highlight marine microbes as both sensitive indicators of environmental stress and active contributors to ecosystem recovery. By bringing together recent scientific insights, this study underscores the essential role of marine microorganisms in ocean ecosystem regulation and climate change adaptation and emphasizes the need to incorporate microbial processes more fully into ocean monitoring, climate modeling, and sustainable marine management efforts.
Continue reading ‘The invisible engine of the oceans: marine microorganisms driving climate resilience and ecosystem stability: a literature review’Decadal biogeochemical predictions for the bottom marine environment of the Northeast U.S. Continental Shelf
Published 27 February 2026 Science Leave a CommentTags: chemistry, modeling, North Atlantic, regionalmodeling
The Gulf of Maine and the surrounding Northeast U.S. Continental Shelf are experiencing rapid marine environmental change arising from complex regional dynamics that challenge near-term (1–10 years) predictive capabilities for valuable living marine resources. Here, using a high-resolution regional ocean model, we demonstrate skilful decadal forecasts of ocean bottom habitat characteristics including bottom temperature, dissolved oxygen (O2), pH and aragonite saturation state (Ωar). Bottom temperature and pH predictions show substantial skill driven primarily by radiatively forced warming and carbon uptake trends, while bottom O2 and Ωar predictions benefit more from initialization due to stronger internal variability. Retrospective forecasts successfully predicted observed historical changes in water masses and environmental properties, including recent cooling/freshening transitions driven by replacement of Warm Slope Water with Labrador Slope Water. This water mass variability also modulates biogeochemical conditions and ocean acidification buffering capacity, with our recent forecasts indicating that benefits from the expected respite from rapid warming might be tempered by challenges posed by rapid acidification. The demonstrated predictability of coupled physical-biogeochemical processes supports developing integrated prediction systems for climate-informed marine resource management.
Continue reading ‘Decadal biogeochemical predictions for the bottom marine environment of the Northeast U.S. Continental Shelf’Physiology and survival of intertidal calcifiers in two contrasting upwelling systems
Published 27 February 2026 Science Leave a CommentTags: adaptation, biological response, field, laboratory, mollusks, morphology, mortality, otherprocess, physiology, South Pacific
Climate change alters the oceans’ temperature, pH, and oxygen concentration. These changes are expected to increase globally over the coming decades, affecting a wide range of marine organisms. Coastal upwelling zones, characterized by their high environmental variability, serve as ideal natural laboratories to study the potential impacts on marine organisms and ecosystems of temperature change, acidification, and ocean deoxygenation. The estimation of survival using capture‐mark‐recapture (CMR) data has been commonly applied to vertebrates, and to date, very few studies have been done on marine invertebrate organisms. In this study, we combined field CMR data and laboratory measurements to assess the physiological responses (metabolic rate and heart rate) and survival probability of individuals in two populations of intertidal mollusks, Chiton granosus and Scurria zebrina, in contrasting upwelling environments (i.e., semi‐permanent vs. seasonal). We found that (1) there are no differences between the two studied populations for heart rate in both species, (2) the S. zebrina population subjected to seasonal upwelling has a higher metabolism, (3) there are no differences in the calcification rate between the two studied populations of both species, and (4) survival is significantly higher in the semi‐permanent upwelling location for both species. Our findings highlight species‐specific responses to contrasting upwelling regimes, suggesting that phenotypic plasticity and survival differences may influence resilience under ongoing climate change.
Continue reading ‘Physiology and survival of intertidal calcifiers in two contrasting upwelling systems’Seawater pH fluctuations during the Ordovician to Silurian transition: insights from δ11B records in carbonates
Published 26 February 2026 Science Leave a CommentTags: chemistry, field, North Pacific, paleo
Highlights
- A positive δ11Bcarb excursion has been observed during the Hirnantian coinciding with Gondwana glaciation.
- Seawater pH fluctuations during the OST are caused by declining atmospheric pCO₂, sea level fall and carbonate weathering.
- The fluctuation of seawater pH exerted a crucial role in the climatic changes and biotic evolutions during the OST.
Abstract
Environmental changes during the Ordovician to Silurian transition (OST) and the cause of Late Ordovician Mass Extinctions (LOMEs) remain a subject of debate. This study presents the first continuous seawater pH record spanning the Late Ordovician and Early Silurian, based on carbonate boron isotope (δ11Bcarb) data obtained from a carbonate-dominated section in South China. Our results reveal predominantly stable δ11Bcarb values throughout the Late Ordovician and Early Silurian, punctuated by a positive δ11Bcarb excursion during the Hirnantian coinciding with Gondwana glaciation. The calculated seawater pH pattern indicates a generally low pH baseline across the OST, temporarily interrupted by a transient increase in surface ocean pH coinciding with the glacial episode. These pH fluctuations are interpreted to result from a combination of factors, including declining atmospheric pCO₂ levels, sea level changes, weathering of carbonate rocks, and decomposition of organic matter. This study suggests that the fluctuation of seawater pH exerted a crucial role in the climatic changes and biotic evolution during the OST. The enhanced carbonate weathering and increased seawater pH, together with sea level fall and a reduction in shelf area, likely contributed to the decreased net accumulation of carbonates and represented a negative feedback for the development of glaciation and cooling climate. Given that the living of organisms (e.g. brachiopod, conodont, sponge and radiolarian) was sensitive to the changes in seawater pH, if and how the seawater pH fluctuations affected the LOMEs still needs more detailed work in the future.
Continue reading ‘Seawater pH fluctuations during the Ordovician to Silurian transition: insights from δ11B records in carbonates’Natural analogues of climate change can reveal fish responses across multiple levels of biological organisation
Published 26 February 2026 Science Leave a CommentTags: biological response, field, fish, review, vents
Anthropogenic climate change is threatening ecosystem functionality and biodiversity globally. While significant research has been dedicated to understanding how organisms may respond to future climate change, most of these studies focus on individual levels of biological organisation in controlled laboratory settings, which often fail to capture the complexity of natural ecosystems. Organisms respond to climate stressors across various levels of biological organisation, which also involve complex interactions or feedback mechanisms among levels, making it difficult to generalise responses to climate change from laboratory experiments or single levels alone. Natural analogues provide a unique opportunity to observe complex ecological interactions in real-world environments with long-term exposure to climate change stressors. Here, we provide a systematic literature review to reveal how natural analogues of ocean warming and ocean acidification can be used to assess fish responses to climate change across multiple levels of biological organisation (from molecular to biogeographical scales) and to assess how cross-level buffering and feedback mechanisms may shape fish species persistence in a future ocean. We identify key knowledge gaps and propose research frameworks that integrate natural analogues with laboratory experiments, mesocosms, and predictive models to better capture the complexity of fish responses to climate stressors in a more holistic way. Finally, we highlight the importance of coordinated, cross-system research using multiple natural analogues to reveal adaptive mechanisms and strengthen predictions of fish community reorganisation under climate change.
Continue reading ‘Natural analogues of climate change can reveal fish responses across multiple levels of biological organisation’A standardised experimental setup for simulating ocean warming and acidification in benthic marine invertebrates
Published 26 February 2026 Science Leave a CommentTags: biological response, laboratory, Mediterranean, methods, mollusks, multiple factors, porifera, temperature
Recent studies identify ocean warming and acidification as major drivers of ecological change in the Eastern Mediterranean, posing serious threats to marine biodiversity, particularly for sessile or low-mobility organisms that cannot escape unfavourable conditions. At the same time, the need for standardised experimental approaches capable of generating high-quality data on organismal responses to multiple climate stressors has become increasingly evident. This manuscript presents a fully detailed and replicable experimental framework for simulating ocean warming and acidification in benthic marine invertebrates under controlled laboratory conditions. Detailed protocols include the technical set-up, experimental design, selection of climate scenarios, monitoring procedures and criteria for species selection and demonstrating its application through a validation case study from the MACCIMO project.
Continue reading ‘A standardised experimental setup for simulating ocean warming and acidification in benthic marine invertebrates’Ocean acidification reduces diatom and photosynthetic gene abundance on plastic in an coastal bay mesocosm experiment
Published 25 February 2026 Science Leave a CommentTags: abundance, biological response, BRcommunity, community composition, laboratory, mesocosms, molecular biology, North Pacific, otherprocess, phytoplankton, prokaryotes
Discarded plastics are accumulating in the global ocean and posing threat to marine life. The plastisphere – the community colonizing plastic surfaces – profoundly influences plastic’s environmental behavior, affecting its degradation and entry into marine food webs. Ocean acidification (OA) resulted from anthropogenic CO2 emissions, is also threatening marine ecosystems, but the effect of OA on the structure and ecological function of the plastisphere community remains poorly understood. Here, using a mesocosm experiment, we investigated the effects of OA on the plastisphere colonizing floating PET plastic bottles. The study was conducted using subtropical eutrophic coastal water from Southern China under two CO2 conditions: increased CO2 to 1000 μatm (HC) and ambient CO2 410 μatm (LC). Metagenomic sequencing of the plastic samples, after exposure for 32 days, showed striking changes in relative abundance of eukaryotes and bacteria caused by HC. There was a 75.3 % decrease in eukaryote read abundances at high CO2, most strikingly a 95.6% decrease in the relative abundance of diatoms. In addition, the relative abundance of genes involved in photosystem II light reactions and pigment synthesis decreased under high CO2 conditions. This suggests that OA could reduce the photosynthetic potential within the plastisphere. Shifts in plastisphere community structure and potentially diminished photosynthesis under OA could influence the food chains within plastisphere, plastic degradation, transportation, and carbon cycle involving plastics. Overall, our results suggest that OA can alter the functional ecology of the plastisphere, with potential implications for marine biogeochemical processes and food web dynamics in subtropical eutrophic coastal water.
Continue reading ‘Ocean acidification reduces diatom and photosynthetic gene abundance on plastic in an coastal bay mesocosm experiment’Ocean acidification modifies site fidelity and patterns of seagrass habitat use by a herbivorous fish
Published 25 February 2026 Science Leave a CommentTags: algae, biological response, BRcommunity, field, fish, Mediterranean, morphology, performance, physiology, vents
Ocean acidification (OA), characterized by changes in seawater chemistry and a concomitant decline of pH due to the uptake by seawater of the atmospheric CO2, will profoundly shape marine ecosystems. The lower pH/higher pCO2 can act negatively (as a stressor for organisms with a calcareous exoskeleton) or positively (as a direct resource for primary producers like macrophytes). Consequently, herbivores may indirectly benefit from OA counteracting the direct negative effects of living under high pCO2/low pH conditions. Here, we investigated how OA may influence site fidelity, habitat use, and trophic behaviour patterns of Sarpa salpa, the main herbivorous fish associated with Posidonia oceanica meadows in the north-western Mediterranean Sea. We assessed if and how OA influences the habitat use of S. salpa by comparing natural tags, in otoliths and muscle tissues, between CO2 vents and reference pH sites. We did not find differences in otolith elemental composition and shape among fish exposed to different pH conditions (CO2 vent vs ambient pH sites). However, otolith isotopic signatures differed between life stages (young vs sub-adults), consistent with the variations observed in seawater-dissolved inorganic carbon across sites. Finally, comparisons of the nutritional value marine vegetation (macroalgae, P. oceanica, epiphytes) showed that P. oceanica and epiphytes were more nutritious at CO2 vents, along with increased consumption by S. salpa. This trophic separation indicates that S. salpa spent more time exploiting the trophic resources in the CO2 vents. Together, our findings shed new light on plant–herbivore interactions within P. oceanica meadows under future OA scenarios.
Continue reading ‘Ocean acidification modifies site fidelity and patterns of seagrass habitat use by a herbivorous fish’Climate change impacts on coral reefs and emerging resilience pathways: a systematic review
Published 25 February 2026 Science Leave a CommentTags: biological response, corals, review
Highlights
- Rising temperatures, acidification, sea level rise and storms are accelerating coral bleaching and reef weakening worldwide.
- Review of 220 studies from 1996–2025 reveals major biodiversity loss and high risk of reef collapse under warming.
- The 2023–2025 global bleaching event impacted about 84 percent of reefs, the most severe on record.
- Coral gardening, larval restoration, assisted evolution and connected marine protected areas boost reef resilience.
- Emission cuts combined with local conservation, community stewardship and adaptive management are vital for reef survival.
Abstract
Coral reefs are one of the ecosystems that are most affected by climate change, but they also support biodiversity, coastal stability, fisheries, and tourism around the world. This review uses a structured narrative literature review based on PRISMA protocols to put together evidence from 220 peer-reviewed articles (1996 to 2025) to see how warming seas, ocean acidification, rising sea levels, and stronger storms change coral ecology, structure, and ecosystem functioning. The results indicate that heightened thermal stress is the principal catalyst of mass bleaching and mortality, occurring with greater frequency and at larger spatial scales, whereas ongoing acidification persists in diminishing calcification, skeletal density, and recruitment success. The rise in sea level and damage caused by storms make habitat loss happen even faster, make reefs less complex, and make communities of reef-associated species less stable. Even though things are going this way, new interventions like coral gardening, larval propagation, assisted evolution, marine protected areas, and community-led co-management show promise for making things more resilient in the face of future climate change. The review emphasizes the necessity of immediate global carbon reduction in conjunction with customized conservation and restoration strategies at the local level. If no strong action is taken, coral reefs may not last long, and the economic security they provide may also go down.
Continue reading ‘Climate change impacts on coral reefs and emerging resilience pathways: a systematic review’Plasticity and adaptation in a changing ocean: a review of research trends and challenges
Published 24 February 2026 Science Leave a CommentTags: adaptation, biological response, otherprocess, review
Climate change and ocean acidification pose significant challenges to both terrestrial and aquatic ecosystems, making it critical to understand species’ vulnerability. Phenotypic plasticity and evolutionary adaptation are key mechanisms enabling organisms to cope with environmental shifts, with marine species appearing particularly susceptible. This semi-quantitative bibliometric review, conducted following PRISMA guidelines, examines research on climate change and ocean acidification impacts on marine organisms, focusing on plasticity and adaptation. We analysed 168 peer-reviewed articles published between 1995 and 2024 from Web of Science and Scopus. Publications remained low until 2013, then increased threefold, peaking in 2019, with the US, Australia, and China leading. Research predominantly addressed marine animals, especially fish, bivalves, and other invertebrates. Most studies focused on plasticity (57%) and examined molecular traits as response variables. Temperature, pH, and their combination were the most studied environmental drivers, whereas salinity and dissolved oxygen received little attention. Conceptual ambiguities in the use of plasticity and adaptation were noted. Our review highlights research gaps and emphasizes the need for integrated studies on plasticity and adaptation to better understand marine species’ vulnerability to climate change and ocean acidification and guide effective conservation and management strategies.
Continue reading ‘Plasticity and adaptation in a changing ocean: a review of research trends and challenges’Understanding the resilient carbon cycle response to the 2014–2015 Blob event in the Gulf of Alaska using a regional ocean biogeochemical model
Published 24 February 2026 Science Leave a CommentTags: chemistry, modeling, North Pacific, regionalmodeling
Marine heatwaves (MHWs), characterized by anomalously high sea surface temperatures, are occurring with increasing frequency and intensity, profoundly impacting ocean circulation, biogeochemistry, and marine ecosystems. The MHW known as the Blob, which persisted in the subarctic NE Pacific from 2014 to 2015, significantly affected surrounding ecosystems. Warming-induced solubility reduction is expected to raise the partial pressure of carbon dioxide (pCO2) in the surface water, causing outgassing of CO2 to the atmosphere. Outgassing of CO2 is another source of atmospheric CO2 in addition to anthropogenic fossil fuel burning. However, moored observations at Ocean Station Papa (OSP; 145° W, 50° N) shows a moderate decrease in oceanic pCO2 during the Blob, resisting the warming-induced outgassing of CO2. This response is opposite of what is expected from warming alone, and instead has been attributed to reductions in dissolved inorganic carbon (DIC), although the mechanisms driving this reduction have remained unclear. We employed a regional model that accurately reproduces the temporal variability of oceanic pCO2 at OSP to investigate the cause of decrease pCO2 during the Blob. The analysis of model outputs indicates that the observed oceanic pCO2 decline resulted from the offset between warming-induced solubility reduction (increasing pCO2) and weakened physical transport of DIC (decreasing pCO2), with the latter dominating. Both horizontal and vertical transports played important roles. The near-surface carbon budget over the broad region was primarily driven by changes in the vertical transport. The decrease in DIC during the Blob resulted from the suppression of upwelling of DIC-rich subsurface waters in the winter of 2013. In this period, the horizontal transport also contributed substantially to DIC reduction. In particular, at OSP, the effect of the horizontal transport was comparable to that of the vertical transport, reflecting the northward advection of low-DIC water masses. These findings indicate that changes in physical circulation were the primary driver of the moderately enhanced CO2 uptake observed during the Blob. This study provides a critical insight into the complexity of biogeochemical response to extreme warming events and underscores the importance of resolving physical transport processes in assessing oceanic carbon uptake during MHWs.
Continue reading ‘Understanding the resilient carbon cycle response to the 2014–2015 Blob event in the Gulf of Alaska using a regional ocean biogeochemical model’Shell-shocked: local oyster farmers confront a changing climate
Published 24 February 2026 Media coverage Leave a CommentTags: fisheries, North Pacific
For more than a century, oyster aquaculture has thrived in Morro Bay’s waters, but our changing climate now poses a significant threat to this multi-million-dollar industry. Local farmers are implementing innovative solutions to protect their operations as ocean acidification becomes an increasing concern.
Beneath the waves in Morro Bay, nearly 5 million oysters are growing. Onshore, the hands of shuckers work quickly to keep up with demand.
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However, changing climate conditions are putting aquaculture at risk. Temperature and pH changes, particularly ocean acidification, are creating new challenges for oyster farmers.
Nick Soares from the Morro Bay National Estuary Program works closely with the farmers in the bay and with the research teams keeping a close eye on the bay. He stated, “Temperature, pH being the big one, like ocean acidification, these are all things that we’re very aware of.”
At Cal Poly’s Center for Coastal and Marine Science, researchers are studying these impacts. In Dr. Emily Bockmon’s research lab, students and professors are documenting how rising atmospheric CO2 levels are affecting seawater chemistry. Learn more about her research here!
Continue reading ‘Shell-shocked: local oyster farmers confront a changing climate’Wind control of the interannual ocean‐biogeochemical variability in the South Atlantic Bight
Published 23 February 2026 Science Leave a CommentTags: biogeochemistry, chemistry, modeling, North Atlantic, regionalmodeling
Abstract
In the South Atlantic Bight (SAB), changes in the Gulf Stream (GS), particularly its strength and proximity to the coast, are thought to be primary factors determining the shelf-break upwelling rate. However, it is still not entirely clear if and to what extent those factors influence cross-shelf nutrient fluxes and shape the ocean biogeochemistry at interannual and longer timescales. Here, we use a high-resolution regional ocean-biogeochemical model and an ocean reanalysis product (1993–2022), along with a satellite-derived chlorophyll data set (1997–2022), to investigate the interannual ocean-biogeochemical variability in the SAB. Regional model outputs suggest that year-to-year changes in phytoplankton production are indeed largely driven by upwelling of cold and nutrient-rich water to the shelf-break. The upwelling variability, reflected in bottom temperature and vertically integrated production patterns, is strongly linked to surface velocity changes in the GS near the shelf break, but weakly related to the depth-integrated GS transport. The GS’s velocity changes, and the temperature and production anomalies, are well correlated to the alongshore wind stress, suggesting that local wind is the leading driver of the shelf-break upwelling variability at interannual timescales. Those relationships are also supported by circulation patterns from ocean reanalysis and satellite chlorophyll anomalies. Finally, examining the simulated shelf-slope interchanges in the carbonate system, we find that shelf-break upwelling significantly increases bottom acidification, a pattern linked to the low carbonate concentration in the slope waters. This study thus provides new insight for understanding and predicting GS and winds impacts on biogeochemical patterns from the SAB.
Plain Language Summary
The ocean current known as the Gulf Stream (GS) can induce upwelling of subsurface cold and nutrient-rich waters into the coastal margin of the South Atlantic Bight, influencing coastal temperature and phytoplankton growth. Previous studies suggested that the GS strength and its proximity to the coast are key factors determining the intensity of upwelling events. However, the degree to which these factors impact the year-to-year changes in phytoplankton production and other ocean properties remains unclear. Here we use numerical models of ocean currents and seawater biogeochemistry, as well as chlorophyll records derived from satellite measurements, to investigate that impact. The patterns showed that interannual changes in coastal temperature, phytoplankton production, water acidity, and dissolved oxygen are strongly modulated by upwelling changes in the outer edge of the continental margin (about 70 m depth in this region). This interannual upwelling variability is tightly coupled to variations in the surface alongshore GS velocity close to that outer edge, which is modulated by alongshore wind variability. Our study characterizes GS patterns associated with high and low productivity years, and highlights the role of surface wind as ultimate driver of the interannual upwelling variability in the South Atlantic Bight.
Key Points
- A regional ocean model is used to investigate interannual variability of ocean-biogeochemistry in the South Atlantic Bight
- Year-to-year changes in primary production, chlorophyll, and carbonate system patterns respond to shelf-break upwelling anomalies
- Shelf-break upwelling is closely linked to the Gulf Stream velocity near the shelf break, modulated by alongshore wind variability
Ocean acidification in Canada: the current state of knowledge and pathways for action
Published 23 February 2026 Science Leave a CommentTags: biological response, chemistry, modeling, policy, regionalmodeling, review, socio-economy
Ocean acidification (OA) generally receives far less consideration than other climate stressors and related hazards, such as global warming and extreme weather events. Canada is uniquely vulnerable to OA given its extensive coastal oceans, the oceanographic processes in its three basins, accelerated warming and sea-ice melt, and extensive coastal communities and maritime economic sectors. Canada’s coastline is also home to extensive and diverse First Nations peoples with distinct histories, rights, title, laws, governance and whose traditions and cultures are extrinsically linked to the sea. However, there are currently very limited pathways to support OA action, mitigation, and/or adaptation in Canada, particularly at the policy level. Here, we present a first synthesis of the current state of OA knowledge across Canada’s Pacific, Arctic, and Atlantic regions, including monitoring, modelling, biological responses, socioeconomic and policy perspectives, and examples of existing OA actions and efforts at local and provincial levels. We also suggest a step-wise pathway for actions to enhance the coordinated filling of OA knowledge gaps and integration of OA knowledge into decision-making frameworks. The goals of these recommendations are to improve our ability to respond to OA in Canada, and minimize risks to coastal marine environments and ecosystems, vulnerable sectors, and communities.
Continue reading ‘Ocean acidification in Canada: the current state of knowledge and pathways for action’Pacific cod gene expression analysis reveals how changing oceans impact larvae
Published 20 February 2026 Press releases Leave a CommentTags: biological response, fish, molecular biology, multiple factors, North Pacific, temperature
A new study used gene expression analysis to explore how temperature and ocean acidification affect Pacific cod larvae. Scientists discovered that larvae are equipped with genes that allow them to survive cool and acidified conditions. However, warming may cause mortality by depleting energy and triggering inflammatory responses. These mechanisms are possible links between changes in ocean conditions and the recruitment of young fish in the Gulf of Alaska Pacific cod population.
Decrease in Pacific Cod Population
Pacific cod is a highly valued commercial fishery, and cod also play a key role in the ecosystem as both predator and prey. However, cod populations in Alaska have declined in recent years. Decreased population size is likely linked to recent marine heat waves, and early life stages seem to be the most impacted. Scientists predict that marine heatwaves may be more common in the future and that ocean acidification will intensify, particularly at high latitudes.
Experiments have shown that Pacific cod are sensitive to temperature during their early life stages. Temperature influences how their eggs develop, how their bodies use energy, and how they grow and survive as larvae. We don’t know as much about the impacts of ocean acidification.
In a 2024 study at the NOAA Fisheries Alaska Fisheries Science Center, scientists raised Pacific cod from embryos to larvae at multiple temperatures (3°C, 6°C, 10°C). To examine the potential interaction between temperature and ocean acidification, they also raised them in water that replicated current ocean conditions and in more acidified conditions. This mimicked conditions projected for the end of this century. The study found that larval mortality was very high in warm water but the effect of acidification was more complex.
The effects of temperature and acidified conditions depended on the fish’s development stage. Scientists need to better understand how changing ocean conditions can affect important species like Pacific cod, and whether these species can adapt to these changes.
A Deeper Dive with Gene Expression
This new molecular study examined larvae to understand why heat wave temperatures might cause larvae to die at high rates. “Finding larvae that are dying in the field is very unlikely, but we were able to sample experimental larvae that we knew were dying rapidly due to warming,” said Emily Slesinger, researcher at NOAA’s Alaska Fisheries Science Center. They also sampled larvae exposed to other conditions. The experiments simulated more acidified water and colder temperatures which Pacific cod larvae currently experience in some regions and years. Slesinger continues, “The unique thing about this study’s approach is to look beyond whether these larvae live or die under different conditions, but to understand why through gene expression analysis.”
Continue reading ‘Pacific cod gene expression analysis reveals how changing oceans impact larvae’Blue carbon ecosystems and coral reefs as coupled nature-based climate solutions
Published 20 February 2026 Science Leave a CommentTags: mitigation, review
Restoring coastal ecosystems offers more than just carbon storage: it can also help bring coral reefs back to life. This Perspective explores how the carbon captured by mangroves and other blue carbon systems could be used to support reef restoration, creating a powerful synergy between climate action and marine conservation. By aligning ecological benefits with innovative funding strategies, this approach offers a practical path towards more resilient coastlines and more durable climate solutions.
Continue reading ‘Blue carbon ecosystems and coral reefs as coupled nature-based climate solutions’Short-term mechanisms, long-term consequences: molecular effects of ocean acidification on juvenile snow crab
Published 20 February 2026 Science Leave a CommentTags: adaptation, biological response, crustaceans, laboratory, molecular biology, morphology, mortality, North Pacific, otherprocess, physiology, reproduction
Understanding how marine species tolerate acidified conditions is critical for predicting biological responses to ocean change. A recent one-year experiment (Long 2026) found that juvenile snow crab (Chionoecetes opilio) maintain growth and molting under acidification (pH 7.8, 7.5), and survival begins to decline only after ∼250 days under severe acidification (pH 7.5). In this companion study, we characterized whole-transcriptome responses after 8 hours and 88 days of exposure to identify molecular mechanisms underlying short-term tolerance and chronic effects of ocean acidification. The immediate transcriptional response involved strong activation of genes associated with mitochondrial metabolism and biogenesis, protein homeostasis, cuticle maintenance, and immune modulation, processes shared between moderate and severe treatments but of greater magnitude under severe acidification. After 88 days, expression patterns diverged, revealing sustained upregulation of stress- and damage-mitigation pathways in the severe treatment (pH 7.5) compared to the moderate treatment (pH 7.8). These findings indicate that crabs in severe acidification are likely to experience chronic OA stress that precedes outward physiological effects, and provides a mechanistic basis for delayed mortality. We further highlight potential early indicators of chronic acidification stress in snow crab, among which a gene likely coding for carbonic anhydrase 7 (CA7, GWK47_031192) appears to be the most promising biomarker.
Continue reading ‘Short-term mechanisms, long-term consequences: molecular effects of ocean acidification on juvenile snow crab’Indo-Pacific coral reef sponge diversity declines under predicted future ocean conditions
Published 19 February 2026 Science Leave a CommentTags: abundance, biological response, BRcommunity, community composition, corals, laboratory, mesocosms, multiple factors, North Pacific, otherprocess, porifera, temperature
Future oceans are predicted to favor groups like sponges over calcifying taxa such as scleractinian corals. Here, we test this hypothesis by examining the development of coral reef communities in experimental mesocosms over 23 months. 85 sponge species among the calcifying class Calcarea (~33%), and non-calcifying Demospongiae (~60%) and Homoscleromorpha (<10%) recruited to warming (+2°C), acidification (-0.2 pH), and warming+acidification (+2°C, -0.2 pH) future ocean treatments. The diversity of calcifying sponges was unimpacted across any treatment, whereas non-calcifying classes showed greatest declines. 57-66% of demosponges decreased under future ocean conditions, and homoscleromorphs were entirely absent from acidified treatments. Through the sponge loop, sponges play a fundamental role in coral reef nutrient cycling, and altered coral reef community composition likely has functional consequences. This study challenges the assumption that non-calcifying species are less impacted and highlights the importance of understanding how community composition may alter ecosystem functioning under future ocean conditions.
Continue reading ‘Indo-Pacific coral reef sponge diversity declines under predicted future ocean conditions’Metrological assessment of pHT in TRIS buffers within artificial seawater: implications for high-salinity reference materials
Published 19 February 2026 Science Leave a CommentTags: chemistry, methods
Anthropogenic CO2 emissions drive ocean acidification through changes in the carbonate system, lowering seawater pH. In contrast, salinity variations arise from physical processes such as freshwater fluxes and circulation. This study reports the preparation and Harned cell characterization of three equimolal TRIS buffer solutions (0.01 mol·kg−1, 0.025 mol·kg−1, and 0.04 mol·kg−1) in artificial seawater (ASW) matrices with practical salinities of 35 and 50 and temperatures of 20 °C, 25 °C, and 30 °C. Determined pHT values achieved expanded uncertainties (𝑈pHT ≤ 0.006), meeting Global Ocean Acidification Observing Network (GOA-ON) “climate” quality standards. Absolute salinity (SA) was concurrently measured via density (TEOS-10), revealing systematic deviations from practical salinity due to TRIS content. A nonlinear regression model was developed to predict pHT as a function of salinity, temperature, and TRIS molality, with r2 = 0.99998. These results provide a robust dataset for developing Certified Reference Materials (CRMs) for pHT calibration under climate-relevant high-salinity environments at different temperature conditions, offering a practical tool for high-accuracy calibration in variable marine conditions.
Continue reading ‘Metrological assessment of pHT in TRIS buffers within artificial seawater: implications for high-salinity reference materials’
