Posts Tagged 'review'

Inside the Extinction Envelope: a systemic review and meta-analysis of paleoclimate extinction markers with comments on the necessary array of last-threshold interventions

Every element of the causal chain that produced the five largest mass extinctions of the last half-billion years is presently active in the Earth system. The rate of the modern perturbation exceeds every peer-reviewed paleoclimate reference case. A six-intervention portfolio, deployed together at wartime industrial scale beginning now, is the physically necessary and sufficient response. The window in which that portfolio remains fully effective closes between 2028 and 2040. The anthropogenic-versus-feedback tipping point is expected between 2035 and 2040; corrected for the at-least-order-of-magnitude higher rate of contemporary carbon release, loss of agency — the point at which coordinated intervention can no longer arrest the cascade — arrives 200 to 400 years after feedback engagement under sustained portfolio deployment, and collapses onto the tipping point itself under any scenario in which the portfolio is not deployed within the 2028–2040 window.

Continue reading ‘Inside the Extinction Envelope: a systemic review and meta-analysis of paleoclimate extinction markers with comments on the necessary array of last-threshold interventions’

Present but overlooked: biogenic acidification in aquaculture waters and its implication for mollusc mariculture

Mollusc mariculture, a critical global source of high-quality protein, is increasingly threatened by seawater acidification. While climate-driven ocean acidification (OA) has been widely studied, intensive aquaculture systems face an additional, locally exacerbated phenomenon: biogenic acidification. In this review, we comprehensively compare biogenic acidification with OA and other seawater acidification types, highlighting its occurrence across various aquaculture systems and its capacity to induce conditions more corrosive than end-of-century OA projections under densely stocked settings. Driven by the respiration and calcification of high-density mollusc populations, biogenic acidification leads to distinct alterations in the carbonate chemistry of mollusc farming systems—notably a reduction in total alkalinity (TA)—that are mechanistically different from OA. We further discuss how biogenic acidification imposes stronger physiological stresses on molluscs, impairing calcification, growth, and energy allocation, and how it synergistically interacts with climate change. Finally, we propose practical mitigation strategies, including TA supplementation and integrated multi-trophic aquaculture, to enhance the resilience and sustainability of mollusc farming. This review underscores the necessity to address biogenic acidification as a distinct and ongoing challenge in global mariculture.

Continue reading ‘Present but overlooked: biogenic acidification in aquaculture waters and its implication for mollusc mariculture’

The impact of the CO2 fertilization effect in seagrasses: a comparative perspective with terrestrial plants

This article comments on:

Pazzaglia J, Marín-Guirao L, Ambrosino L, Pes K, Costa M, Barrote I, Silva J, Procaccini G. 2025. Handling the heat: ocean acidification mitigates the effects of marine heatwaves on Posidonia oceanica seedlings. Journal of Experimental Botany 76, 6958–6973. https://doi.org/10.1093/jxb/eraf276.

Seagrass meadows are among the world’s most ecologically and economically important marine ecosystems. Although they cover only 0.1% of the seafloor, they sequester carbon at rates rivalling tropical rainforests, protect coastlines, and support marine biodiversity (do Amaral Camara Lima et al., 2023). Yet they are declining globally due to anthropogenic pressures including coastal development, pollution, and climate change (Waycott et al., 2009; Dunic et al., 2021). While ocean acidification and ocean warming are pervasive stressors under accelerating global change, Pazzaglia et al. (2025) have demonstrated that elevated dissolved CO2 may enhance seagrass resilience by increasing thermal tolerance in Posidonia oceanica seedlings through the CO2 fertilization effect.

Continue reading ‘The impact of the CO2 fertilization effect in seagrasses: a comparative perspective with terrestrial plants’

Functional saturation of Earth’s habitable domains: constraints on land systems and potential in marine environments

In this context, functional saturation is defined as the state in which a system’s capacity to sustain additional productive or regulatory functions becomes constrained due to cumulative anthropogenic pressures, even if some physical space remains available. This review examines whether the progressive contraction of terrestrial plant communities under intensifying anthropogenic pressure can be functionally compensated by the expansion of marine macroalgal systems in a high-CO2 world. Integrating perspectives from Earth system ecology, biogeochemistry, and spatial analysis, the study evaluates three interdependent dimensions: the saturation of habitable terrestrial space, the relative openness yet ecological constraint of marine environments, and the dynamic coupling between atmospheric CO2 and ocean chemistry. The synthesis reveals a fundamental asymmetry between land and ocean systems. Terrestrial ecosystems are undergoing direct structural transformation through land-use change, resulting in a measurable contraction of ecologically functional space and increasing transgression of planetary boundaries. In contrast, marine systems retain substantial geometric space but are subject to diffuse, cumulative stressors, particularly in productive coastal zones where macroalgal communities are most viable. Elevated CO2 exerts dual effects on marine primary producers, simultaneously enhancing photosynthetic potential while intensifying ocean acidification, with temporally lagged responses mediated by air–sea exchange dynamics. Although macroalgae may exhibit localized increases in productivity, their capacity to provide long-term carbon sequestration and ecosystem stability remains inherently limited due to rapid biomass turnover, susceptibility to regime shifts, and the interaction of multiple stressors. The available evidence suggests that marine macroalgal expansion is unlikely to fully compensate for terrestrial vegetation loss at global ecological and biogeochemical scales. Instead, the Earth system is undergoing a net reduction in biospheric resilience, characterized by declining terrestrial complexity and increasingly unstable marine productivity. These findings challenge assumptions of compensatory redistribution of primary production and underscore the necessity of preserving terrestrial ecosystems alongside mitigating pressures on marine environments.

Continue reading ‘Functional saturation of Earth’s habitable domains: constraints on land systems and potential in marine environments’

Environmental regulation of interspecific interactions among macrobenthic seaweeds and its implications for community phase transition

Macrobenthic seaweeds are key species in temperate and boreal nearshore rocky ecosystems, and their interspecific interactions profoundly affect the species composition, spatial distribution and dynamic succession of the community. This paper systematically reviews the mechanisms of interspecific competition and facilitative effects among macrobenthic seaweeds. We also examine their environmental regulation and impacts on community phase transitions. Competition mainly centers on three major resources: light, space and nutrients. It manifests as an asymmetric hierarchical structure, in which canopy-forming species exert a disproportionate repressive effect on lower algal layers through light competition. Facilitative effects are realized through several mechanisms. These include canopy shading to mitigate heat stress and water loss, physical structure building to create complex habitats, and nutrient retention with chemical microenvironment regulation. Moreover, the relative strengths of facilitation and competition shift systematically across environmental stress gradients. Multi-trophic level regulation further shapes community diversity maintenance mechanisms through the suppression of dominant species by vegetative predators and the cascading effect of top predators on vegetative predators. In the context of global change, physiological asymmetries driven by oceanic heat waves are tilting the competitive balance in favor of opportunistic turf algae. These algae form a lock-in state through the triple positive feedbacks: physical barriers, biogeochemical deterioration, and chemosensory exclusion. This significantly decreases the resilience of algal field recovery. Tropical coral-macroalgae phase transition is highly consistent with the degradation of temperate algal fields in terms of driving logic. They follow the law of coupling resource competition imbalance, downward regulatory relaxation, and positive feedback lock-up. This paper suggests several priorities for future research. Studies should focus on the nonlinear response of multifactor interaction, the quantitative correlation between key functional traits and community resilience, and the establishment of a cross-ecosystem comparison framework. These efforts will provide theoretical support for predicting and adaptively managing offshore ecosystems under global change.

Continue reading ‘Environmental regulation of interspecific interactions among macrobenthic seaweeds and its implications for community phase transition’

Bioturbation under stress: linking coastal environmental change to the physiology and function of marine bioturbators

Coastal benthic habitats are increasingly exposed to human-driven environmental changes, resulting in multiple co-occurring stressors. Bioturbators, which provide vital ecosystem services, are particularly vulnerable due to their limited mobility and are directly exposed to these multiple stressors. However, the ecological impacts of these stressors on bioturbators, especially their activity levels, remain poorly understood. This review synthesizes current knowledge on how selected environmental stressors, including extreme weather events, eutrophication, and anthropogenic emissions, affect bioturbation, organismal physiology and survival. Reported impacts vary widely depending on the species and stressors’ intensity. The strongest negative effects were typically observed under high-intensity stressor scenarios, which sometimes exceeded environmentally relevant thresholds. However, only a few studies examined the combined effects of multiple stressors. Their effects on bioturbators can be neutral, antagonistic, synergistic or additive, highlighting the complexity of stressor interactions in natural systems. The summary of this review suggests that key ecosystem functions provided by bioturbators are threatened by constant exposure to multiple environmental stressors and that ongoing environmental changes are further exacerbating this situation. To better understand the risks faced by these organisms, it is important to explore the combined effects of multiple stressors, to support more accurate predictions and effective conservation and restoration efforts.

Continue reading ‘Bioturbation under stress: linking coastal environmental change to the physiology and function of marine bioturbators’

Microplastics in a warming ocean with coupled climate change interactions and implications for marine ecosystem functioning

Highlights

  • Climate driven processes intensify microplastic fragmentation and redistribution.
  • Microplastics disrupt carbon cycling and climate sensitive ocean processes.
  • Warming acidification and ice melt amplify microplastic impacts on marine biota.
  • Polar ice acts as a major reservoir and emerging source of legacy microplastics.
  • Integrating microplastics into climate policy is critical for ocean resilience.

Abstract

Microplastics (MPs) pollution and climate change are now recognized as two pervasive and interacting stressors reshaping marine ecosystems, yet their combined effects remain insufficiently integrated within marine pollution research. This review synthesizes current global evidence on how climate-driven processes modulate the sources, transport, fate, and ecological impacts of MPs, and how MPs in turn influence climate-linked ocean processes. A systematic literature review was conducted following PRISMA principles, drawing on peer-reviewed studies retrieved from major scientific databases without temporal restriction. A total of 205 publications included for qualitative synthesis. The results demonstrate that ocean warming, acidification, sea-ice melt, extreme weather events, and altered circulation patterns intensify MP fragmentation, redistribution, and bioavailability across marine environments. Warming accelerates polymer degradation and enhances biological interactions, acidification alters surface chemistry and toxicity, and polar ice melt releases large reservoirs of legacy MPs into vulnerable ecosystems. Evidence further shows that MPs disrupt key climate-related processes, including primary productivity, nutrient cycling, and the biological carbon pump, thereby creating feedbacks that may weaken oceanic climate regulation. Combined exposure to MPs and climate stressors amplifies physiological stress, reduces growth and reproductive performance, and compromises resilience across multiple trophic levels. These findings highlight that MPs are not passive contaminants but active modifiers of climate-sensitive marine systems. Integrating MP dynamics into climate research, monitoring frameworks, and policy instruments is therefore essential. Addressing plastic pollution alongside climate mitigation and adaptation strategies will be critical to safeguarding marine ecosystem functioning under future global change.

Continue reading ‘Microplastics in a warming ocean with coupled climate change interactions and implications for marine ecosystem functioning’

Behavioural responses of fishes to abiotic stressors: a comparative synthesis of shared physiological mechanisms and ecological consequences

Highlights

  • Comparative review of behavioural responses to major abiotic stressors
  • Conserved physiological mechanisms underlie diverse behavioural responses
  • Cross-stressor synthesis identifies common and stressor-specific effects
  • Ecological consequences extend from individuals to populations
  • Research priorities for predicting fish responses to global environmental change

Abstract

Anthropogenic activities, including global warming, deforestation, urbanization, intensive agriculture, and aquaculture, are accelerating environmental change with consequences for aquatic ecosystems. As ectothermic vertebrates, fishes are sensitive to alterations in abiotic conditions, responding through behavioural changes that influence survival, reproduction, and species interactions. Although several studies have investigated the effects of abiotic stressors, comparative syntheses across stressors remain limited, constraining our understanding of how environmental drivers influence fish behaviour. In this review, we synthesize evidence on the impacts of six abiotic stressors, including temperature, hypoxia, acidification, turbidity, salinity, and ammonia, and examine the processes underlying responses. Across these stressors, behavioural alterations affect swimming performance, feeding, predator avoidance, social interactions, habitat selection, exploration, courtship, and anxiety-like behaviours. Despite differences in their primary modes of action, these stressors frequently converge on physiological disturbances involving oxidative stress, neurotransmitter regulation, sensory impairment, ion homeostasis, and energy metabolism, ultimately producing behavioural outcomes with ecological consequences. Most studies have been conducted under controlled laboratory settings, limiting ecological relevance. Furthermore, the combined effects of multiple abiotic stressors, together with long-term, multigenerational, and transgenerational responses, remain poorly understood despite their potential consequences for fish growth, reproduction, recruitment, and community structure. This review highlights the urgent need for integrative, multi-stressor, and multigenerational studies spanning diverse species, developmental stages, and ecosystems to improve predictions of fish responses under environmental change. By identifying shared and stressor-specific responses, this synthesis provides a conceptual framework for understanding how abiotic stressors affect fish through physiological pathways that ultimately converge on common behavioural outcomes with important ecological implications.

Graphical abstract

Continue reading ‘Behavioural responses of fishes to abiotic stressors: a comparative synthesis of shared physiological mechanisms and ecological consequences’

Carbon in the ocean

This chapter examines the role of the oceans as the largest active surface reservoir of carbon in the Earth system and the chemical and physical processes that regulate the storage and redistribution of carbon in seawater. The oceans contain roughly 38,700 Gt of carbon, about fifty times more than the atmosphere, mostly in the form of dissolved inorganic carbon distributed among carbonic acid, bicarbonate, and carbonate species, whose proportions are largely controlled by seawater pH and alkalinity. The chapter introduces the fundamental equilibria of the marine carbonate system, including gas exchange with the atmosphere governed by Henry’s law, and explains how dissolved inorganic carbon and alkalinity determine the ocean’s capacity to absorb atmospheric CO2. It also reviews the origin and composition of seawater and the geochemical processes responsible for ocean salinity. Finally, the chapter describes the major mechanisms transferring carbon from the surface ocean to deeper waters, by the solubility, biological, and carbonate pumps, and examines how the depth of the saturation state of calcium carbonate, the lysocline, and the carbonate compensation depth regulate carbonate sedimentation and provide long-term negative feedback on atmospheric CO2.

Continue reading ‘Carbon in the ocean’

The future of aquatic food systems: climate change adaptation and resilience strategies – a narrative review

Across the world’s oceans, lakes, and rivers, climate change is reshaping fisheries and aquaculture systems on which billions of people depend for food and millions rely for their livelihoods. This narrative review summarizes peer-reviewed and selected literature published between 2008 and 2026 on climate impacts, adaptation options, and critical knowledge gaps in marine and freshwater fisheries, with a particular focus on tropical and African inland fisheries. This review shows that warming, acidification, deoxygenation, and altered hydrology are disrupting fish physiology; shifting the distribution of marine species poleward by over 70 km per decade, at rates that vary greatly by taxon, depth, and area; and destroying critical habitats. Although this rapid poleward shift is well documented in open marine environments, it contrasts sharply with landlocked or fragmented freshwater systems, where horizontal migration is physically constrained, a contrast central to the concept of climate entrapment developed in this review. In scenarios characterized by high emissions, tropical fisheries may see a reduction of up to 40% in their maximum catch potential, a statistic relevant to specific tropical Exclusive Economic Zones based on bioclimate-envelope forecasts, which should not be interpreted as a global or universal result. This figure is a model-derived projection under a bioclimate-envelope framework rather than an observed trend, and the realized outcome will depend on future emission pathways. These biophysical changes compound already serious pressures, overfishing, habitat loss, and pollution, and the burden falls heaviest on those least responsible: small-scale fishers, women, and indigenous communities. We introduce the concept of climate entrapment to describe the distinct vulnerability of freshwater fisheries: trapped by fragmented habitats and hydrological barriers, fish stocks cannot migrate to more secure waters as conditions deteriorate. While there are promising adaptation strategies, major gaps remain in understanding what works, for whom, and under what conditions. We conclude with priority recommendations for research, policy, and practice.

Continue reading ‘The future of aquatic food systems: climate change adaptation and resilience strategies – a narrative review’

The effects of ocean warming and acidification on fatty acid contents of marine organisms: a global meta-analysis

Ocean warming and acidification pose significant threats to marine biodiversity and human nutrition by fundamentally altering the biochemical composition of marine organisms. A primary concern is the potential decline in omega-3 fatty acids (FAs) that are essential to human health and primarily obtained through seafood consumption. The influence of these climate stressors on FA content across marine food webs remains poorly understood. To address this critical knowledge gap, we conducted a global meta-analysis of 489 experiments across 143 publications and 132 marine species, quantifying the effects of warming and acidification on nutritionally important FAs in marine primary producers, invertebrates and fishes. Under warmer conditions, we detected reductions of up to 34% and 50% in omega-3 FA proportions and concentrations, respectively, and up to 53% in omega-3: omega-6 ratios, together with increases of up to 22% and 17% in saturated FA proportions and concentrations, respectively across taxa groups. Critically, these effects were intensified as warming increased. The most severe reductions in omega-3 FAs were observed in primary producers, suggesting that climate-driven changes at the base of the food web could impair trophic transfer of these micronutrients, limiting nutrient availability for higher trophic levels and ultimately humans. Ocean acidification, conversely, demonstrated a minor overall effect on FA levels, although this result was based on substantially fewer studies. Furthermore, we identified species from environments with broader temperature ranges, diatoms, herbivorous invertebrates and low-resilience fish to display larger reductions in omega-3 FA proportions under warming. Our meta-analysis further highlighted the need for long-term studies under ecologically realistic conditions to improve predictions of nutritional responses to climate change. These findings are essential for understanding how the nutritional value of species change under climate change, and can inform fisheries management, aquaculture and public health policy aimed at securing the future availability of these vital micronutrients.

Continue reading ‘The effects of ocean warming and acidification on fatty acid contents of marine organisms: a global meta-analysis’

Potentially toxic elements in multi-stressor marine environments: bioaccumulation, ecosystem impacts, and human health implications

Potentially toxic elements pollution in marine environments is intensifying under anthropogenic activities and climate-driven changes, yet the interactive effects of multiple stressors on metal bioaccumulation, ecosystem health, and human risk remain inadequately synthesized. This review aims to quantitatively integrate multi-stressor interactions involving ocean warming, acidification, and eutrophication with potentially toxic elements dynamics across coastal, estuarine, and open ocean systems. Following PRISMA guidelines, 154 peer-reviewed studies from 652 screened records were synthesized to establish a comprehensive, evidence-based framework for predictive risk assessment. This review indicates that multi-stressor conditions fundamentally alter speciation and bioavailability of mercury (Hg), cadmium (Cd), lead (Pb), arsenic (As), and chromium (Cr), producing synergistic and other non-additive effects that amplify biomagnification. Methylmercury (MeHg) exhibits the strongest trophic magnification, with factors reaching 11.1 in polar shelf ecosystems, while cadmium and lead show biodilution yet elevated tissue burdens in benthic organisms under combined warming and acidification. Arsenic speciation shifts toward more toxic inorganic forms under acidification, and chromium bioavailability increases with pH-dependent redox changes. Sublethal effects, including reproductive impairment, oxidative stress, and metabolic disruption, cascade to population declines and impaired ecosystem functions, with early life stages exhibiting up to 40% greater sensitivity under combined exposures. Human health risk assessments reveal that seafood-consuming populations face elevated risks, with hazard quotients for mercury exceeding one in high-consumption groups, lifetime cancer risks from arsenic and cadmium surpassing safe thresholds, and lead and chromium contributing to cardiovascular and renal toxicities. These findings suggest that current regulatory thresholds, which overlook interactive effects and additive toxicities, systematically underestimate cumulative threats in a changing ocean, necessitating urgent adoption of integrated, climate-aware frameworks aligned with international instruments such as the Minamata Convention on Mercury to protect marine ecosystems and human health.

Continue reading ‘Potentially toxic elements in multi-stressor marine environments: bioaccumulation, ecosystem impacts, and human health implications’

Coastal and marine ecosystems under climate change ecological and socio-environmental impacts

Coastal and marine systems are some of the most biologically productive and economically important systems on Earth, yet they are being compromised at an accelerating pace by climate change. Ocean warming, marine heatwaves, sea-level rise, ocean acidification and deoxygenation along with increasing extreme events are interacting to change the structure, function and resilience of ecosystems among coral reefs, mangroves seagrass meadows and salt marshes. Although effort has been devoted to understanding individual ecosystem effects of climatic change, we know less about comparative mechanistic synthesis and cross-ecosystem vulnerability trajectories. This synthesis explores recent understanding of the biophysical determinants of ecosystem decline, with particular reference to thresholds, regime shifts and feedbacks that limit capacity to adapt. We explore different sensitivities among these biogenic coastal systems, and explain why coral reefs are confronted with sharp thermal and carbonate chemistry thresholds, while mangroves and tidal wetlands have threshold-based resilience contingent on sediment supply and geomorphologic setting. Beyond ecological effects, we compile social–environmental responses including fishery reduction, coastal defense loss and blue carbon release, and rising human vulnerability especially in small island and developing coastal regions. The review also examines ecosystem-based adaptation and nature-based solutions, considering their co-benefits and implementation challenges in a high-emission world. By synthesizing climate drivers, ecosystem thresholds, and social–ecological tipping points within a unified conceptual framework, this review integrates mechanisms of change and alternative stable-state transitions to improve understanding of coastal ecosystem resilience under accelerating climate change.

Continue reading ‘Coastal and marine ecosystems under climate change ecological and socio-environmental impacts’

Natural environmental drivers of seagrass degradation: a global systematic review with implications for Indonesia

Highlights

  • Thermal stress was the most studied natural driver of seagrass decline.
  • Study frequency reflects research effort, not ecological importance.
  • Most multi-stressor studies assessed only two interacting drivers.
  • Warming–acidification effects varied among species and exposure contexts.
  • Indonesia remains underrepresented in long-term seagrass research.

Abstract

Seagrass ecosystems are exposed to natural environmental variability and climate-modulated extremes that can interact with anthropogenic pressures and accelerate ecological decline. This systematic review synthesized 60 peer-reviewed publications published between 2010 and 2025 to examine how temperature and marine heatwaves, ocean acidification and pH, salinity, drought and flooding, hydrodynamics, sea-level change, turbidity and light limitation, sediment conditions, and oxygen availability affect seagrass ecosystems. Thermal variables were the most frequently investigated category; however, publication frequency was treated as an indicator of research effort rather than a ranking of ecological importance. Experimental and field evidence showed that warming and marine heatwaves often reduce growth, photosynthetic performance, biomass, and recovery, although outcomes depend on species, exposure duration, light, nutrients, and prior stress history. Evidence for warming–acidification interactions was contrasting: acidification impaired plant performance during thermal stress in some studies, whereas enhanced inorganic carbon availability supported biomass or carbon metabolism in others. Most multi-stressor experiments evaluated only two drivers, and relatively few examined three or more simultaneous or successive stressors. The most commonly reported ecosystem consequences included habitat contraction, canopy and biomass loss, physiological impairment, altered carbon and nutrient cycling, sediment destabilization, community reorganization, and reduced resilience. Geographic evidence remained concentrated in Europe, the Mediterranean, Australia, China, and North America. Indonesia and much of Southeast Asia were comparatively underrepresented despite high seagrass diversity and documented declines associated with interacting environmental change. Future research should prioritize standardized long-term monitoring and multifactorial experiments that distinguish research frequency from ecological effect and support regionally calibrated risk assessment.

Continue reading ‘Natural environmental drivers of seagrass degradation: a global systematic review with implications for Indonesia’

Environmental regulation and disruption of shell biomineralization in bivalves and gastropods: a mechanistic review

Molluscan shells are increasingly threatened by a complex array of environmental stressors—climate-related drivers, changes in seawater chemistry, contaminants, and biotic cues. This review provides a mechanistic synthesis of how these stressors disrupt the biomineralization process across life stages. We develop a conditional hierarchical response framework from the reviewed evidence. The framework links ionoregulatory and acid-base disturbances with molecular, microstructural, and shell-level responses, while allowing for compensatory, nonlinear, species-specific, and life-stage-specific outcomes. This molecular disruption manifests as defects in calcium carbonate (CaCO3) crystalline microstructure, which may in turn compromise shell macro-scale physical properties (strength, hardness, growth). We synthesize combined and context-dependent effects of co-occurring stressors and distinguish formally tested interactions from qualitative comparisons of combined treatments. Future research must leverage integrated multi-omics, advanced in vivo imaging, and multi-stressor experimental designs to unravel candidate molecular and physiological thresholds and predict adaptive potential. This framework may help identify testable mechanisms, evidence gaps, and context-dependent vulnerabilities relevant to conservation.

Highlights

  • A conditional framework links molecular, microstructural, and shell-level responses.
  • Early stages often show high sensitivity, although direct ontogenetic comparisons remain limited.
  • Energy limitation is a recurrent, but often indirectly inferred, physiological constraint.
Continue reading ‘Environmental regulation and disruption of shell biomineralization in bivalves and gastropods: a mechanistic review’

Shark responses to ocean acidification: physiological buffering, behavioural vulnerability, and comparative insights from teleost fishes

Highlights

  • Sharks maintain acid-base balance under elevated CO₂ via effective buffering.
  • Physiological compensation carries energetic costs that constrain aerobic scope.
  • Olfactory-mediated foraging is more OA-sensitive than baseline locomotor function.
  • Multi-stressor effects (warming + OA) amplify biological impacts across life stages.
  • Evidence is biased toward benthic species; pelagic sharks remain understudied.

Abstract

Ocean acidification (OA), driven by increasing atmospheric carbon dioxide (CO₂), is a major component of global ocean change with widespread implications for marine organisms. Sharks (elasmobranchs) are often assumed to be relatively resilient to OA due to their distinctive physiology, including strong acid–base regulation and urea-based osmoconformation. However, empirical evidence evaluating this assumption remains limited and fragmented. This review synthesizes current knowledge on the physiological, behavioural, and sensory responses of sharks to OA within a comparative framework that incorporates insights from teleost fishes. A systematic literature search following PRISMA guidelines identified studies examining OA effects across shark species and life stages. Available evidence indicates that sharks generally maintain extracellular acid-base balance under elevated CO₂, demonstrating effective physiological buffering. However, this compensation is not without cost. Energetic trade-offs, reduced aerobic scope under multi-stressor conditions, and alterations in metabolic and oxidative responses have been reported. Behavioural and sensory-mediated processes, particularly olfactory-driven foraging, appear more sensitive to OA, with impairments emerging even in the absence of obvious physiological failure. Responses are highly species-specific and often amplified by co-occurring stressors such as warming. Despite these findings, current data are strongly biased toward small, benthic species, with limited representation of pelagic taxa and long-term responses. Sharks cannot be considered uniformly resilient to OA; rather, their responses are context-dependent, energetically constrained, and potentially consequential at population and ecosystem levels. Future research integrating long-term, multi-stressor, and mechanistic approaches will be critical for improving predictions of shark responses under ongoing ocean change.

Continue reading ‘Shark responses to ocean acidification: physiological buffering, behavioural vulnerability, and comparative insights from teleost fishes’

Characterizing decision optimization strategies for managing climate change impacts on aquatic ecosystems and public health in Asia

Climate change is dramatically reshaping the delicate balance of Asia’s freshwater and marine ecosystems, intensifying threats to biodiversity, water quality, and public health. This review explores the profound interconnections between climate change and aquatic environments, highlighting the escalating risks posed by rising temperatures, shifting precipitation patterns, and extreme weather events. The paper delves into the alarming surge in harmful algal blooms, shifts in species distributions, and the increasing prevalence of waterborne diseases, all of which undermine both potable water sources and food security. In addition, the review examines the compounding impact of pollution, which further exacerbates the vulnerability of aquatic ecosystems. As global temperatures rise, the resulting decrease in dissolved oxygen and proliferation of pathogens create hostile environments for aquatic life, while extreme climatic events exacerbate water contamination and scarcity in many regions. Vulnerable communities, heavily reliant on aquatic resources for survival, face a dual challenge of environmental and socioeconomic instability. As Asia’s aquatic ecosystems continue to face unprecedented stress, proactive interventions are essential to safeguard food security, water resources, and public health for future generations.

Continue reading ‘Characterizing decision optimization strategies for managing climate change impacts on aquatic ecosystems and public health in Asia’

Climatic factors effects on gastropods (Phylum: Mollusca): a review of the biodiversity of freshwater, marine, and terrestrial snails

Climate change is altering ecosystems worldwide through rising temperatures, changing precipitation patterns, and more frequent extreme weather events, including heatwaves. Gastropods in freshwater, marine, and terrestrial environments are affected through changes in habitat characteristics, geographic distribution, abundance, physiology, and behavior. In freshwater systems, warming and drought can reduce dissolved oxygen and shrink suitable habitats. In marine environments, ocean acidification can impair shell formation and, under severe conditions, dissolve calcium-carbonate shells. In terrestrial habitats, increasing temperature and declining soil moisture can force snails into prolonged inactivity and increase desiccation risk. Effective climate information, predictive models, and early-warning systems are therefore essential for climate resilience, biodiversity conservation, and disease-risk management. Further comparative research is needed to clarify how phylogenetic history and adaptive variation influence heat tolerance and resilience among gastropod taxa.

Continue reading ‘Climatic factors effects on gastropods (Phylum: Mollusca): a review of the biodiversity of freshwater, marine, and terrestrial snails’

Climate change drivers of harmful algal blooms in marine and coastal ecosystems

Climate change is widely recognized to contribute to marine warming, acidification, and deoxygenation, while the frequency of harmful algal blooms (HABs) is increasing, causing severe ecological disruptions. Eutrophic regions are increasingly exposed to thermal extremes, hypoxic conditions, and low pH levels and may therefore serve as sensitive indicators of ecosystem responses to climate forcing. HAB occurrence reflects interactions among nutrient availability, temperature variability, and hydrodynamic conditions. Future work should aim to quantify the relative contributions of interacting environmental drivers to improve the robustness of predictive models of HAB dynamics under future climate scenarios. Climate change is likely to amplify HAB intensity and spatial distribution, although regional outcomes depend on interacting environmental drivers. These findings have implications for fisheries management, aquaculture sustainability, public health issues and long-term monitoring. Monitoring strategies should ideally prioritize ecosystem functional responses and early-warning indicators of climatic variability.

Continue reading ‘Climate change drivers of harmful algal blooms in marine and coastal ecosystems’

Calcium carbonate formation in coastal macroalgal ecosystems via multiple pathways

Calcium carbonate formation in coastal macroalgal ecosystems via multiple pathways

Highlights

  • Focused on a novel inorganic carbon sequestration pathway of non-calcifying macroalgae.
  • Clarified algae-bacteria synergistic driving mechanism for calcium carbonate precipitation.
  • Systematically sorted out potential mineralizing microbial taxa within the phycosphere and their core metabolic pathways.

Abstract

Macroalgae are dominant primary producers that drive carbon sequestration in coastal ecosystems. Macroalgal carbon sequestration primarily refers to the long-term storage of macroalgae-derived organic carbon in the ocean. However, calcium carbonate (CaCO3) formation is frequently observed in non-calcifying macroalgal environments, suggesting the existence of an overlooked inorganic carbon process in macroalgal ecosystems. Here, we introduce multiple pathways that may drive CaCO3 formation in macroalgal ecosystems. These include the effects of macroalgal photosynthesis and carbon-concentrating mechanisms on the seawater carbonate system, the role of phycosphere interfacial properties in facilitating CaCO3 nucleation, and the macroalgae-bacteria synergy that promotes CaCO3 formation. We identified several current knowledge gaps—the unclear carbon sequestration or source effect of CaCO3 formation in macroalgal ecosystems and the stability of CaCO3 minerals in macroalgal ecosystems—that require further investigation. This review advances the understanding of macroalgal carbon cycling beyond organic pathways and emphasizes the importance of a comprehensive assessment of macroalgal carbon sequestration, including that of inorganic carbon.

Continue reading ‘Calcium carbonate formation in coastal macroalgal ecosystems via multiple pathways’

Subscribe

Search

  • Reset

OA-ICC Highlights

Resources