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’Posts Tagged 'toxicants'
Environmental impact on calcifying organisms: focus on the effects of river runoff and ocean acidification on health status and pollutant bioaccumulation
Published 29 September 2026 Science ClosedTags: biogeochemistry, biological response, chemistry, corals, field, growth, Mediterranean, multiple factors, physiology, temperature, toxicants, vents
This doctoral thesis presents a multi-scale and interdisciplinary investigation into the impacts of climate change and anthropogenic pressures on coastal marine ecosystems, integrating the regional dynamics of the Adriatic Sea and the broader context of the Mediterranean Sea. This research combines long-term environmental data analysis with physiological and biochemical studies on key indicator species to elucidate the complex, and often synergistic, nature of the major threats facing these vulnerable environments. The first part of the work highlights a shift in the Adriatic Sea’s physical and biogeochemical regime, from historical eutrophication toward contemporary oligotrophic conditions. The combined effects of reduced Po River runoff and climate-driven warming, particularly during summer, modify the hydrography of the entire basin. These changes have cascading effects, clearly visible in the clam Chamelea gallina. Northern populations, while showing short-term resilience (e.g., higher survival in air), exhibit a lower condition index and higher bioaccumulation of trace metals, which activate costly metabolic defense mechanisms. This energetic stress makes the populations more vulnerable to additional pressures, possibly aligning with the recurrent mass mortality events. The second part of this work was conducted at the Panarea CO2 vents, which constitute a natural laboratory for assessing future global change impacts. Through the study of the coral Balanophyllia europaea, it is found that ocean acidification (OA), especially when combined with ocean warming, significantly impairs coral tissue regeneration, with species-specific responses. A crucial finding was that OA appears to stimulate a response mediated by the coral’s microbiome, enhancing its bacterial degradation capacity and reducing the presence of PAHs in coral tissues. Collectively, this work demonstrates that synergistic stressor interactions pose the greatest threat to marine ecosystems. While evidence of resilience emerges through physiological and microbial adaptations, the findings emphasize the urgent need for integrated management strategies that address cumulative impacts across scales.
Continue reading ‘Environmental impact on calcifying organisms: focus on the effects of river runoff and ocean acidification on health status and pollutant bioaccumulation’Evaluating the combined effects of harmful algal blooms and low pH exposure on the development and hatching success of Artemia salina
Published 21 September 2026 Science ClosedTags: biological response, communityMF, crustaceans, laboratory, morphology, multiple factors, North Atlantic, reproduction, toxicants, zooplankton
Highlights
- Hatching success of Artemia salina was impaired by acidified conditions.
- Development of Artemia salina pre-nauplii was negatively impacted by both species of harmful algae and low pH exposure.
- Only toxin-producing harmful algal species produced significant morphological abnormalities of pre-naupliar Artemia salina.
- No synergistic effects of harmful algae and low pH exposure was seen in this study.
Abstract
Harmful algal blooms (HABs) and ocean acidification are major stressors in coastal marine ecosystems, yet their combined effects on early zooplankton development remain poorly understood. This study tested whether HABs and low pH exposure exert synergistic effects on the embryonic development and hatching success of brine shrimp (Artemia salina) cysts. Cysts were exposed to controls, toxin-producing HAB species (i.e. Margalefidinium polykrikoides or Alexandrium catenella), or a non-toxin producing HAB control (i.e. Gymnodinium aureolum) and at either ambient (pH ∼ 8) or acidified (pH ∼ 7.2) conditions. We hypothesized that the combined exposure to a toxin-producing HAB at acidified pH conditions would reduce hatching success and alter embryonic morphology. Low pH exposure consistently reduced hatching success and slowed developmental progression across treatments, reducing nauplii production. HAB exposure alone did not affect hatching success, but exposure to toxin-producing HABs in ambient pH conditions did significantly increase the morphological abnormalities at the membrane stage. Overall, no synergistic effects of HABs and low pH exposure were found for any response variable. Instead, HABs and low pH exposure exerted distinct, stage-specific impacts that were additive rather than interactive. These findings suggest that while exposure to toxin-producing HABs primarily disrupts morphology and low pH exposure slows development and reduces hatching success, their combined effects do not exceed additive expectations. Future work should explore physiological mechanisms underlying these stress responses and assess whether similar patterns occur in other cyst-producing zooplankton.
Development of hypoxia and acidification during harmful algal blooms: dynamic multi-stressor conditions in NY, USA, estuaries
Published 14 July 2026 Science ClosedTags: algae, biological response, chemistry, field, multiple factors, North Atlantic, sensor, toxicants
Highlights
- Alexandrium blooms occurred with normoxic conditions and moderate pH (7.5-8.0).
- Alexandrium blooms occurred with moderate pCO2 (400 – 1,000 µatm) and saturating conditions for aragonite.
- Dinophysis blooms co-occurred nocturnal acidification (8.71 to 13.6 hr d−1) and hypoxia (0.52 to 3.88 hr d−1).
- Dinophysis blooms co-occurred with high pCO2 (1,000 – 3,500 µatm) and undersaturated aragonite (Ωar < 1).
- The co-occurrence of nocturnal hypoxia, acidification, Ωar undersaturation, and HABs coupled is a significant threat for marine life.
Abstract
While harmful algal blooms (HABs), hypoxia, and ocean acidification are common occurrences in coastal zones, research investigating the co-occurrence and interactions between these processes has been lacking. Here, we documented the initiation, peak, and demise of eight distinct HAB events caused by Alexandrium catenella and Dinophysis acuminata over a two-year period in two estuaries (Northport Harbor and Cold Spring Harbor, NY, USA). We concurrently characterized the dynamics of carbonate chemistry, including pCO2 and the saturation state of aragonite (Ωar), pH, dissolved oxygen (DO), and general environmental conditions in space and time. HABs occurred in succession and reached high densities with A. catenella blooms exceeding 104 cells L−1 being succeeded by D. acuminata blooms exceeding 106 cells L−1. A. catenella blooms occurred during spring months under generally normoxic conditions with moderate levels of pCO2 (400 – 1,000 µatm), only brief periods of acidification (pH < 7.5), mostly saturating conditions for aragonite, and an absence of hypoxia. In contrast, D. acuminata blooms, which occurred in summer, consistently co-occurred with bouts of extended nocturnal acidification (8.71 to 13.6 hr d−1) and hypoxia (0.52 to 3.88 hr d−1) coupled with higher levels of pCO2 (1,000 – 3,500 µatm), and undersaturating conditions for aragonite (Ωar < 1). During both blooms, nearshore locations hosted higher cell densities, lower pH and DO, and higher pCO2 compared to open water regions. The co-occurrence of multiple stressors including nocturnal hypoxia, acidification, Ωar undersaturation, and HABs, coupled with strong diel cycling of DO, pH, and pCO2, especially during D. acuminata blooms, represents a significant and previously unrecognized threat for marine life.
Continue reading ‘Development of hypoxia and acidification during harmful algal blooms: dynamic multi-stressor conditions in NY, USA, estuaries’Evaluating the combined effects of ocean acidification and harmful algal blooms on the fitness of Artemia salina
Published 6 July 2026 Science ClosedTags: biological response, crustaceans, laboratory, 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’Interactive effects of triclosan, microplastic vectors, and ocean warming–acidification on sea urchin embryo development
Published 6 July 2026 Science ClosedTags: 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’Combined effects of ammonium and pH on sea urchin embryogenesis: insights for sediment quality assessment
Published 30 April 2026 Science ClosedTags: biological response, echinoderms, laboratory, Mediterranean, multiple factors, physiology, reproduction, sediment, toxicants
Highlights
- Reduced pH enhances ammonium toxicity on sea urchin embryos in filtered seawater.
- In elutriates ammonium is a major driver of P. lividus embryotoxicity.
- Data support setting ammonium thresholds in sediment quality frameworks.
- Ocean acidification potentially increases ammonium toxicity for sea urchin larvae.
Abstract
Ammonium is a key component of coastal marine systems, originating from both natural and anthropogenic sources, with possible toxic effects on marine organisms depending on the concentration and pH. This study evaluates, for the first time, the combined effects of ammonium and seawater acidification on early development of the sea urchin Paracentrotus lividus under both laboratory conditions and exposure to environmental matrices derived by dredged sediments from harbor area. Embryos were incubated with increasing concentrations of ammonium in filtered seawater at pH 8.1 and 7.6, as well as in sediment elutriates from the Pescara harbor (Adriatic Sea, Italy), selected as a case study with relevant concentrations of ammonium (0.1–3.5 mg/L). A combined effect between ammonium and pH was observed, with increasing ammonium toxicity by ∼20% at pH 7. Moreover, in sediment elutriates, ammonium affect sea urchin embryo development, with EC50 ranging between 1.388 and 1.538 mg/L NH4+ at pH 8.1 and 7.6, respectively, without significant differences due to pH. Chemical analyses of sediments confirmed low levels of trace metals and organic pollutants, indicating that ammonium is the primary driver of embryotoxicity without a direct toxic effect of other contaminants. The results further underscore the need to integrate ammonium assessment into sediment quality frameworks and for management strategies, particularly in the context of future ocean acidification, to safeguard the early life stages of sensitive marine invertebrates.
Continue reading ‘Combined effects of ammonium and pH on sea urchin embryogenesis: insights for sediment quality assessment’Research progress on the comprehensive response mechanisms of marine organisms to multiple environmental stressors
Published 28 April 2026 Science ClosedTags: biological response, corals, fish, mollusks, multiple factors, plastics, review, toxicants
The ocean constitutes a vital component of the Earth’s ecosystem, serving as the breeding and habitat ground for marine organisms. Currently, the global marine ecosystem is confronting combined threats from multiple environmental stressors, such as seawater warming, acidification, hypoxia, and microplastic pollution. Research focusing solely on individual stressors can hardly reveal the authentic response patterns of marine organisms accurately. This paper presents a comprehensive review. It systematically integrates cutting-edge research findings from recent years. The review centers on two core themes. These themes are the interactive effects of multiple environmental stressors and the response mechanisms of marine organisms. Studies indicate significant species-specific differences in organism responses to combined stress. These differences exist across various organism groups. Additionally, the interactive effects of multiple environmental stressors often induce biological responses. These responses deviate from the predictions derived from single-factor studies. The research results presented herein can provide crucial theoretical support for the conservation of marine biological resources, the restoration of biodiversity, and the protection of the marine ecological environment. Meanwhile, they lay a foundation for the establishment of predictable marine stress-response relationship models.
Continue reading ‘Research progress on the comprehensive response mechanisms of marine organisms to multiple environmental stressors’Combined ecotoxicity of microplastics and crude oil co-pollutants: occurrence, distribution and its synergistic impact with ocean acidification on Artemia franciscana
Published 3 April 2026 Science ClosedTags: biological response, crustaceans, Indian, laboratory, multiple factors, physiology, plastics, reproduction, toxicants, zooplankton
Microplastics (MPs) are recognized as a global concern, with specific attention shifted towards marine MPs pollution. This particular study investigates the abundance and distribution of crude oil-loaded microplastics (COMPs) along the Chennai coastline, Tamil Nadu, India and evaluates their combined toxicological effects with ocean acidification on Artemia franciscana. Spatial analysis revealed that Ennore Creek exhibited the highest MP concentration (10.82 ± 0.2 items/L). Polypropylene was recorded as the predominant polymer type followed by low density polyethylene and polyethylene terephthalate, with particle size ranging from 250 to 500 µm. COMPs were detected across all sampling sites, with concentrations declining from Ennore Creek (0.21 ± 0.03 items/L) to Kasimedu Beach (0.10 ± 0.02 items/L). The adsorption of crude oil on MPs is primarily mediated by physical interaction with multi-layer adsorption behaviour. The results highlighted that increase in MP concentration and decrease in seawater pH significantly induced acute toxicity and oxidative stress responses in A. franciscana. At pH 7.8, experimental groups exposed to 0.5 mg/mL of COMPs developed higher ROS, SOD and catalase activity (p<0.001). Whereas control groups alone showed significant increase in oxidative stress responses at lower pH level such as pH 7.8 and 8.0. Combined exposure of COMPs and low pH conditions significantly increased oxidative damages in A. franciscana and affected its hatching ability. The observations from this study emphasize the urgent need for integrated monitoring and further research to explore combined toxicological effects of MPs and ocean acidification to other marine organisms as well.
Continue reading ‘Combined ecotoxicity of microplastics and crude oil co-pollutants: occurrence, distribution and its synergistic impact with ocean acidification on Artemia franciscana’Multi-level holobiont dysregulation increases the ecological risk of combined ocean acidification and benzo[a]pyrene pollution to the reef-building coral Porites lutea
Published 17 March 2026 Science ClosedTags: archaea, biological response, BRcommunity, community composition, corals, laboratory, molecular biology, multiple factors, North Pacific, otherprocess, photosynthesis, physiology, phytoplankton, prokaryotes, toxicants
Highlights
- Combined ocean acidification and BaP induce holobiont dysregulation, evidencing by a decoupled Symbiodiniaceae proliferation and a collapse of the archaeal Nanoarchaeota-Halobacterota symbiosis.
- The coral host shifts its defense strategy from antioxidant capacity to cellular homeostasis, while the bacterial community increases functional redundancy, revealing a costly acclimation mechanism.
- The multi-level dysregulation demonstrates an underestimated ecological risk, highlighting that current single-stressor risk assessments are inadequate for protecting corals under complex pollution scenarios.
Abstract
Reef-building corals are increasingly threatened by the combined effects of global climate change and localized organic pollutants. However, the holistic impacts of co-exposure to ocean acidification (OA) and benzo[a]pyrene (BaP) on coral holobionts remain poorly understood. Here, we investigated the multi-level responses of the reef-building coral Porites lutea to short-term (7-day) exposure to OA (pH 7.80), BaP (10 µg/L), and their combination, by integrating physiological measurements with microbiome profiling (ITS2 and 16S rRNA). We found that combined stress was associated with a dysregulated response in Symbiodiniaceae, characterized by a significant increase in cell density without a parallel rise in chlorophyll content, suggesting a possible compensatory but inefficient proliferation response. Despite this, the dominant symbiont Cladocopium C15 remained stable. The bacterial diversity increased (e.g., enrichment of Ruegeria and Acanthopleuribacter, decline of Endozoicomonas), which may suggest enhanced functional redundancy, while the archaeal community was significantly restructured, most notably a marked decline of the putative obligate Nanoarchaeota–Halobacterota symbiosis. At the host level, combined stress was associated with suppressed antioxidant enzyme activities (SOD/POD) but upregulated genes related to protein folding (Hsp90) and calcium homeostasis (NCX1, VAMP4). These findings suggest a complex holobiont reconfiguration under combined stress, involving a stabilized core symbiont, altered microbiomes, and a shifted host defense strategy. Our study suggests that the ecological risk of combined OA and organic pollution may not be extrapolated from single-stressor responses, indicating the need to incorporate multi-stressor frameworks into coral reef risk assessments.
Continue reading ‘Multi-level holobiont dysregulation increases the ecological risk of combined ocean acidification and benzo[a]pyrene pollution to the reef-building coral Porites lutea’Ocean acidification enhances TiO2 nanoparticle toxicity in Oryzias melastigma: dominant role of size effects in driving bioaccumulation and hepatotoxicity
Published 21 October 2025 Science ClosedTags: biological response, fish, laboratory, molecular biology, multiple factors, physiology, toxicants
Highlights
- OA reduces TiO₂ NPs aggregation/sedimentation, increasing NP bioaccumulation
- NPs preferentially accumulate in liver, inducing hepatotoxicity via oxidative stress
- Size effect outweighs biological resistance as primary NP toxicity driver under OA
- Combined OA-NPs suppress hepatic genes, activate senescence and cell death pathways
- First evidence quantifying hydrodynamic size dominance in OA-enhanced NP toxicity
ABSTRACT
Ocean acidification (OA) and engineered nanoparticles (NPs) pollution represent two critical global environmental challenges. Marine organisms are suffering from their combined stress. However, few studies address their combined effects, and the toxicity mechanisms of NPs under OA are largely unresolved. In this study, we investigated the responses of the marine medaka Oryzias melastigma to environmentally relevant concentration of TiO2 NPs (1.0 mg/L) under OA (pH 7.40). We found that OA alleviated the aggregation and sedimentation of NPs, and decreased the resistance ability of the marine medaka to NPs stress, leading to elevated bioaccumulation of TiO2 NPs. Notably, NPs preferentially accumulated in the liver, inducing hepatotoxicity through oxidative stress and histopathological and ultrastructural damage. Critically, an integrated biomarker approach quantified the relative contributions of size effects (58%) and biological resistance (42%) to NP toxicity under OA, demonstrating that hydrodynamic size dominates toxicity outcomes. Transcriptomic analysis further revealed suppressed hepatic gene transcription and translation, alongside activated cellular senescence and programmed cell death pathways under combined exposure. These findings provide critical insight into the combined toxicity mechanisms of NPs and OA, significantly advancing our understanding of the profound risks that NPs pose to marine ecosystems under OA conditions.
Continue reading ‘Ocean acidification enhances TiO2 nanoparticle toxicity in Oryzias melastigma: dominant role of size effects in driving bioaccumulation and hepatotoxicity’The impact of an early exposure to 17α-ethynylestradiol on the physiology of the three-spined stickleback (Gasterosteus aculeatus) under current and future climatic scenarios
Published 9 October 2025 Science ClosedTags: biological response, fish, laboratory, molecular biology, morphology, mortality, multiple factors, reproduction, temperature, toxicants
Highlights
- RCP8.5 scenario modulated some of the long-lasting physiological responses to EE2.
- RCP8.5-EE2 group led to sex and tissue specific responses.
- RCP8.5-EE2 scenario resulted in lower body length at five months post-contamination.
- RCP8.5 reduced survival rate of embryo-larval but not juvenile stages.
- Early-life exposure to EE2 led to stickleback feminisation.
- Early-life exposure to EE2, led to long-lasting effect on stickleback physiological responses.
Abstract
Ocean warming and acidification are climate change related drivers that impact the physiology of marine organisms and their ability to cope with future environments. Marine ecosystems are also facing pollution from an ever-growing diversity of chemical contaminants, including endocrine disruptors. A common example is the 17α-ethynylestradiol (EE2), which can affect the endocrine regulation of fish and hence potentially impact their fitness. Thus, fish have to cope to multiple climatic and chemical stresses that can interact, influencing the overall impact on fish physiology. In this study, we investigated whether the direct and carry-over effect of early exposure to EE2 (15 ng.L−1; one month during embryo-larval development) are modulated by the RCP8.5 scenario (+3°C; -0.4 pH unit). Five months post-contamination, we measured survival, growth and reproductive axis of prepubertal sticklebacks. Our findings revealed that the survival of juveniles, when exposed to EE2 during early development, is reduced under Current but not RCP8.5 scenario. Furthermore, under RCP8.5-EE2, a significantly lower body length was observed. Sex and tissue specific responses in terms of the expression profiles of genes related to development and sexual maturation was reported. Interestingly, significant interaction between RCP8.5 and EE2 was observed for the expression of ovarian aromatase (cyp19a1a), suggesting a long-lasting estrogenic effect under RCP8.5 scenario. Additionally, the skewed sex ratios and the presence of intersex individuals in both scenarios early exposed to EE2 suggested a feminization due to EE2, which could potentially disrupt sexual maturation and future reproduction. Hence, the early EE2 exposure had carry-over physiological effects on sticklebacks, and these effects can be modulated by the climate scenario. This underscores the importance of conducting long-term multi-stress studies to comprehensively understand the vulnerability on fish populations in future environments.
Continue reading ‘The impact of an early exposure to 17α-ethynylestradiol on the physiology of the three-spined stickleback (Gasterosteus aculeatus) under current and future climatic scenarios’Molecular markers of stress in the sea urchin embryo test: analysing the effect of climate change and pollutant mixtures on Paracentrotus lividus larvae
Published 15 August 2025 Science ClosedTags: biological response, echinoderms, laboratory, molecular biology, morphology, multiple factors, North Atlantic, plastics, reproduction, temperature, toxicants
Highlights
- Combined effects of ocean stressors on sea urchin larvae were analysed.
- RNA-seq revealed key transcriptional changes under stressor combinations.
- Larval growth and deformities worsened with acidification and warming.
- Biomarkers for early detection of stress in marine larvae were identified.
- Insights contribute to predicting organismal responses to climate change.
Abstract
Climate change and pollution represent critical stressors for marine ecosystems, particularly for calcifying organisms such as the sea urchin Paracentrotus lividus. This study examines the combined effects of ocean acidification (OA), ocean warming (OW), and microplastics (MP) loaded with chlorpyrifos (CPF), a broad-spectrum organophosphate insecticide, on sea urchin larvae, evaluating growth and molecular endpoints. Experimental treatments simulated future ocean conditions predicted for 2100, exposing larvae to varying temperature and pH levels, alongside CPF-contaminated MP. RNA sequencing (RNA-seq) was utilized to assess gene expression changes, revealing significant transcriptional shifts in metabolic, cellular, and developmental pathways. Morphological responses showed reduced larval growth, exacerbated under OA and OW conditions. Molecular analyses identified key upregulated pathways associated with stress response, including nitrogen metabolism and extracellular matrix remodelling, while downregulated genes involved DNA stability, cell cycle regulation, and enzymatic activities. These findings suggest a dual compensatory and deleterious response to combined stressors. Notably, temperature acted as a modulator of stressor effects, amplifying oxidative stress and metabolic costs at higher temperatures. Potential biomarkers, such as genes involved in actin regulation and embryonic development, were identified, offering possible tools for early detection of environmental stress. This study highlights the compounded impacts of anthropogenic and climate-induced stressors on marine invertebrates, emphasizing the need for integrative molecular approaches in ecotoxicology. Our findings contribute to the understanding of organismal adaptation and vulnerability in the face of global climate change and pollution, informing conservation strategies for marine ecosystems.
Continue reading ‘Molecular markers of stress in the sea urchin embryo test: analysing the effect of climate change and pollutant mixtures on Paracentrotus lividus larvae’Effect of acidification on the chronic toxicity of diclofenac to Daphnia magna
Published 28 July 2025 Science ClosedTags: biological response, laboratory, multiple factors, phytoplankton, reproduction, toxicants
Highlights
- Chronic diclofenac (DCF) exposure was tested in Daphnia magna at pH 7.0 and 8.7.
- An unexpected pH increase in M4 medium was observed during the experiment.
- The NOEC (no observed effect concentration) of DCF was 5 mg l-1 at pH 8.7.
- Initial pH 7.0 prolonged the time to release of the first hatchlings.
- At 1.3 mg l-1 DCF, fewer neonates were observed at pH 7.0 than at pH 8.7.
Abstract
Pharmaceuticals, as ionizable compounds, are a challenging group of pollutants to analyze because the pH of the environment can alter its ecotoxicological features. However, changes in the toxicity of pharmaceuticals toward aquatic organisms were observed even when there was no change in the ionization of the molecules with a pH shift. Therefore, we conducted a study that aimed to check how pH influences the chronic toxicity of diclofenac (DCF, pKa ≈ 4.0) toward Daphnia magna at two pH levels, 7.0 and 8.7, where DCF is obtained as relatively polar anion. The performance of the experiment with OECD 211 was found to be challenging because of the medium pH shift during the exposure test. Acidification increased the toxicity of DCF, reducing the number of neonates (at a concentration of 1.3 mg l-1) and showing a tendency towards delayed hatching and reduced number of hatchings. In addition, the acidification itself also changes D. magna reproduction, affecting the number of hatchings and the first day of hatching. We conclude that the pH, as a factor of toxicity modulation for ionizable compounds, needs to be evaluated and presented in scientific protocols.
Continue reading ‘Effect of acidification on the chronic toxicity of diclofenac to Daphnia magna’Biomarkers responses in the amphipod Tiburonella viscana exposed to the biocide DCOIT and CO2-induced ocean acidification
Published 10 March 2025 Science ClosedTags: biological response, crustaceans, laboratory, multiple factors, physiology, South Atlantic, toxicants, zooplankton
Highlights
- Biomarkers responses in amphipods assessed in sediment testing with the biocide DCOIT;
- Environmentally relevant concentrations of DCOIT produced biomarker responses;
- Enzymatic activities of GST and AChe were reported, including LPO and DNA damage;
- Biomarkers responses were observed in CO2-induced acidification conditions.
Abstract
Anthropogenic carbon dioxide emissions (CO2) have led to climate change and marine acidification, with an estimated decrease in ocean surface pH of 0.3-0.4 units by the end of the current century. Chemical pollution also contributes to biodiversity loss in marine environments. This issue is particularly critical in areas under pressure from shipping activities, where the introduction of new antifouling system formulations poses a major threat to non-target species. The biocide DCOIT is the most widely used alternative to organotin compounds due to its rapid degradation in seawater. The toxicity of waterborne DCOIT to marine organisms has been documented, but sediment-bound effects are limited to apical responses and pH scenarios corresponding to current levels. In this study, we determine in a combined way, the toxicity of DCOIT under marine acidification scenarios assessing biomarker responses in the burrowing amphipod Tiburonella viscana as a parameter of sublethal effects in solid phase exposures. Environmental relevant concentrations of DCOIT caused inhibition of the enzyme glutathione S-transferases (GST), changed acetylcholinesterase-like activity (AChE), and increased DNA damage at pHs of 7.7 and 7.4. For lipid peroxidation (LPO), increased levels caused by DCOIT were found for both control (8.1) and intermediate (7.7) conditions of pH. Our data provides evidence of oxidative and genotoxic effects induced by DCOIT, with activation of detoxification and defense mechanisms in T. viscana. These results are important for ecological risk assessment and managing of antifouling paint biocides in multiple stressors scenarios.
Continue reading ‘Biomarkers responses in the amphipod Tiburonella viscana exposed to the biocide DCOIT and CO2-induced ocean acidification’Adaptive resilience of sea urchins against seawater acidification: a study on egg quality and offspring performance within a volcanic vents area
Published 20 February 2025 Science ClosedTags: adaptation, biological response, echinoderms, field, multiple factors, otherprocess, reproduction, toxicants, vents
Highlights
- Sea urchins were collected within and outside a volcanic carbon vents area
- Egg quality was investigated revealing differences in size and energetic profile
- Offspring performances were tested at 2 pH levels both with and without herbicide
- Sea urchins from the Vents area showed better offspring performance
- Glyphosate-AMPA mixture caused additional but limited effects compared to pH.
Abstract
Local adaptation plays a critical role in an organism’s ability to survive and reproduce in diverse environmental conditions, potentially improving an organism’s response to stressful conditions such as ocean acidification or pollution. In this study, the effects of lower pH coupled with the presence of environmental contaminants were assessed on sea urchins (Paracentrotus lividus) collected outside and inside a volcanic CO2-vent system, where the mean ambient pH is 8.1 and 7.7, respectively.
Both groups of sea urchins were spawned, and offspring were reared at pH 8.1 and 7.7, and in the presence or absence of a mixture of 100 μg/L of glyphosate and its main metabolite aminomethylphosphonic acid. Offspring performance metrics (development, abnormalities, and growth) were investigated under the different exposure conditions. The exposure to reduced pH affected the development and larval growth in echinoplutei obtained from adults of both sites, although to a different extent. Chemicals mixture had an additive effect in slowing embryo development.
Results revealed that sea urchins living within the lower pH Vents area exhibited significantly higher egg quality, which likely enhanced embryonic development, reduced abnormalities, and increased larval size compared to their counterparts outside the Vents system, both in the presence and absence of contaminants. Findings suggest that sea urchins living within the CO2-Vents system developed adaptations to thrive under lower pH conditions. Elevated egg quality and improved offspring performance suggest organisms’ resilience to environmental stressors associated with seawater acidification. Although insights gained from this study are preliminary, mostly due to the limited number of replicates in the egg biochemical analysis, they contribute to unveiling the adaptive capabilities of sea urchins in facing ongoing ocean acidification challenges.
Continue reading ‘Adaptive resilience of sea urchins against seawater acidification: a study on egg quality and offspring performance within a volcanic vents area’Toxicity of PAHs-enriched sediments on meiobenthic communities under ocean warming and CO2-driven acidification scenarios
Published 6 January 2025 Science ClosedTags: annelids, biological response, BRcommunity, community composition, crustaceans, laboratory, mollusks, multiple factors, nematodes, otherprocess, platyhelminthes, sediment, South Atlantic, tardigrada, temperature, toxicants, zooplankton
Highlights
- Temperature rise reduced the densities of Copepoda and certain Nematoda groups.
- CO2 acidification prevented some Nematoda groups from increasing at high temperatures.
- CO2 acidification reduced Copepoda and nauplii densities, but increased Ostracoda.
- Complex interactions increased certain meiobenthic groups exposed to sediment PAHs.
- Global change and pollution showed interactive effects in meiobenthic communities.
Abstract
This study aimed to assess the interactive effects of CO2-driven acidification, temperature rise, and PAHs toxicity on meiobenthic communities. Laboratory microcosms were established in a full factorial experimental design, manipulating temperature (25 °C and 27 °C), pH (8.1 and 7.6), and PAH contamination (acenaphthene + benzo(a)pyrene spiked sediments and negative control). Temperature rise and CO2-driven acidification led to a decrease in the densities of Copepoda. The density of nematodes Pseudochromadora and Daptonema also decreased, while Sphaerotheristus and Sabatieria densities increased, particularly in the absence of CO2-driven acidification. Ostracoda densities increased in the acidified scenario. PAH contamination resulted in decreased Daptonema densities but increased Turbellaria and certain Nematoda genera (e.g. Pseudochromadora). Overall, the results indicate that the changes of meiobenthic communities caused by CO2 acidification, warming, and PAH contamination are shaped by the vulnerability and tolerance of each taxonomic group, alongside indirect effects observed in Nematoda assemblages.
Continue reading ‘Toxicity of PAHs-enriched sediments on meiobenthic communities under ocean warming and CO2-driven acidification scenarios’Synergistic effects of ocean acidification and sulfamethoxazole on immune function, energy allocation, and oxidative stress in Trochus niloticus
Published 9 December 2024 Science ClosedTags: biological response, mollusks, multiple factors, physiology, respiration, toxicants
Highlights
- Dual stress of OA and SMX may harm survival and reproduction in T. niloticus.
- OA increased immune and antioxidant responses in T. niloticus.
- SMX exposure boosted antioxidant responses and oxygen consumption.
- Exposure to OA combined with SMX impaired cellular energy allocation in T. niloticus.
Abstract
Ocean acidification, a major consequence of climate change, poses significant threats to marine organisms, particularly when combined with other environmental stressors such as chemical pollution. This study investigated the physiological responses of Trochus niloticus to a 28-day exposure of ocean acidification and/or sulfamethoxazole, a commonly detected antibiotic in the South China Sea. Exposure to either acidification or sulfamethoxazole individually triggered adaptive responses through immune activation, antioxidant reactions, and metabolic adjustments. However, concurrent exposure resulted in significant adverse effects, including compromised immunity, oxidative damage, and disrupted energy budget. These findings provide new insights into how ocean acidification interacts with antibiotic pollution to synergistically impact marine gastropods, suggesting that multiple stressors may pose greater threats to T. niloticus populations than single stressors alone.
Continue reading ‘Synergistic effects of ocean acidification and sulfamethoxazole on immune function, energy allocation, and oxidative stress in Trochus niloticus’
