Microbial communities in aquaculture seawater are fundamental to ecosystem stability and health, serving as critical indicators of environmental change. However, the specific impacts of large-scale marine cage culture on these planktonic communities remain poorly understood. Using 16S and 18S rRNA sequencing, we assessed prokaryotic and eukaryotic communities in seawater from nearshore and offshore large yellow croaker farms, as well as a non-farmed site on Nanji Island, China. Our analysis revealed ecologically notable taxonomic and functional trends, despite overall community composition showing only modest changes. Cage-culture operations were associated with an apparent reduction in eukaryotic diversity alongside enrichment of heterotrophic (Cryothecomonas aestivalis) and parasitic taxa (Syndiniales). In contrast, prokaryotic communities exhibited increased phylogenetic diversity at the offshore farm, suggesting organic enrichment may drive niche diversification. Functionally, core metabolic pathways were largely conserved, though nitrogen and sulfur cycling processes appeared more prominent in the farmed sites. Co-occurrence networks revealed a modular structure, with key associations surviving False Discovery Rate (FDR) correction, characterized by a negative association between oligotrophic and copiotrophic niches. Crucially, the absence of significant biomarkers for classic pathogens, combined with microbial patterns indicative of system stability, suggests that the microbial community in this region may remain balanced despite the presence of aquaculture activity. These findings provide preliminary insights that could inform the management of ecological sustainability in offshore mariculture.
{"title":"Assessment of microbial community changes in seawater of marine cage- culture large yellow croaker (Larimichthys crocea) farms","authors":"Tumusenge Daniel, Chenchen Hu, Shuaiqing Wang, Guangyang Zhang","doi":"10.1016/j.marenvres.2026.107849","DOIUrl":"10.1016/j.marenvres.2026.107849","url":null,"abstract":"<div><div>Microbial communities in aquaculture seawater are fundamental to ecosystem stability and health, serving as critical indicators of environmental change. However, the specific impacts of large-scale marine cage culture on these planktonic communities remain poorly understood. Using 16S and 18S rRNA sequencing, we assessed prokaryotic and eukaryotic communities in seawater from nearshore and offshore large yellow croaker farms, as well as a non-farmed site on Nanji Island, China. Our analysis revealed ecologically notable taxonomic and functional trends, despite overall community composition showing only modest changes. Cage-culture operations were associated with an apparent reduction in eukaryotic diversity alongside enrichment of heterotrophic (<em>Cryothecomonas aestivalis</em>) and parasitic taxa (Syndiniales). In contrast, prokaryotic communities exhibited increased phylogenetic diversity at the offshore farm, suggesting organic enrichment may drive niche diversification. Functionally, core metabolic pathways were largely conserved, though nitrogen and sulfur cycling processes appeared more prominent in the farmed sites. Co-occurrence networks revealed a modular structure, with key associations surviving False Discovery Rate (FDR) correction, characterized by a negative association between oligotrophic and copiotrophic niches. Crucially, the absence of significant biomarkers for classic pathogens, combined with microbial patterns indicative of system stability, suggests that the microbial community in this region may remain balanced despite the presence of aquaculture activity. These findings provide preliminary insights that could inform the management of ecological sustainability in offshore mariculture.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107849"},"PeriodicalIF":3.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146010854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.marenvres.2026.107850
Hao Sun , Xinchen Miao , Fengfeng Dong , Rong Sun , Xuan Jia , Xing Liu , Zilan Wu , Ziwei Yao , Jiayin Dai , Jianhui Tang , Jianmin Chen , Yitao Pan
This study investigated the occurrence, gas–particle partitioning, and potential sources of legacy perfluoroalkyl acids (PFAAs) and emerging perfluoroalkyl ether carboxylic acids (PFECAs) in the atmospheric estuaries of Laizhou Bay in North China during 2024. The total concentrations of 28 individual per- and polyfluoroalkyl substances (PFAS) ranged from 31.4 to 2340 pg/m3 in the gaseous phase and from 31.0 to 7262 pg/m3 in the particulate phase. The Yellow River estuary exhibited slightly higher atmospheric PFAS pollution levels than the Xiaoqing River estuary. PFECAs dominated both the gaseous (69.2 %) and particulate phases (88.0 %), with concentrations significantly exceeding those of legacy PFAAs. Seasonal variations indicated that particulate PFAS concentrations peaked in winter. However, higher PFAS levels observed during summer at the Yellow River estuary compared with other seasons were attributed to its unique hydrological and meteorological conditions. Gas–particle partitioning analysis revealed that the partition coefficient (Log Kp) of PFECAs exhibited a non-linear “U-shaped” trend with carbon chain length, distinct from the pattern observed for legacy PFAAs. The partitioning behavior of PFECAs differed from that of legacy PFAAs owing to the presence of ether bonds, which altered their fundamental physicochemical properties. The positive matrix factorization model identified five major sources of PFAS in the two estuaries. The similarity in source profiles between the estuaries suggests that PFAS emissions were primarily driven by large-scale, basin-level industrial activities, rather than local geographical variations. The findings underscore the need to include emerging PFECAs in monitoring programs and to develop basin-scale management strategies for PFAS control.
{"title":"Legacy perfluoroalkyl acids and emerging perfluoroalkyl ether carboxylic acids in the atmosphere of Laizhou Bay estuaries: Occurrence, gas–particle partitioning, and potential sources","authors":"Hao Sun , Xinchen Miao , Fengfeng Dong , Rong Sun , Xuan Jia , Xing Liu , Zilan Wu , Ziwei Yao , Jiayin Dai , Jianhui Tang , Jianmin Chen , Yitao Pan","doi":"10.1016/j.marenvres.2026.107850","DOIUrl":"10.1016/j.marenvres.2026.107850","url":null,"abstract":"<div><div>This study investigated the occurrence, gas–particle partitioning, and potential sources of legacy perfluoroalkyl acids (PFAAs) and emerging perfluoroalkyl ether carboxylic acids (PFECAs) in the atmospheric estuaries of Laizhou Bay in North China during 2024. The total concentrations of 28 individual per- and polyfluoroalkyl substances (PFAS) ranged from 31.4 to 2340 pg/m<sup>3</sup> in the gaseous phase and from 31.0 to 7262 pg/m<sup>3</sup> in the particulate phase. The Yellow River estuary exhibited slightly higher atmospheric PFAS pollution levels than the Xiaoqing River estuary. PFECAs dominated both the gaseous (69.2 %) and particulate phases (88.0 %), with concentrations significantly exceeding those of legacy PFAAs. Seasonal variations indicated that particulate PFAS concentrations peaked in winter. However, higher PFAS levels observed during summer at the Yellow River estuary compared with other seasons were attributed to its unique hydrological and meteorological conditions. Gas–particle partitioning analysis revealed that the partition coefficient (Log <em>K</em><sub><em>p</em></sub>) of PFECAs exhibited a non-linear “U-shaped” trend with carbon chain length, distinct from the pattern observed for legacy PFAAs. The partitioning behavior of PFECAs differed from that of legacy PFAAs owing to the presence of ether bonds, which altered their fundamental physicochemical properties. The positive matrix factorization model identified five major sources of PFAS in the two estuaries. The similarity in source profiles between the estuaries suggests that PFAS emissions were primarily driven by large-scale, basin-level industrial activities, rather than local geographical variations. The findings underscore the need to include emerging PFECAs in monitoring programs and to develop basin-scale management strategies for PFAS control.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107850"},"PeriodicalIF":3.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.marenvres.2026.107847
Dinis Costa , Diana Bordalo , Marta Cunha , Amadeu M.V.M. Soares , Susana Carvalho , Rosa Freitas
Although the use of ultraviolet (UV) filters in personal care products is steadily increasing, their ecological consequences remain poorly characterized despite evidence of persistence and bioaccumulation in marine systems. In parallel, climate change stressors such as rising temperatures and fluctuations in salinity are known to modulate the toxicity of contaminants and the physiological tolerance of marine organisms. The combined action of these factors can intensify biological stress, highlighting the need for studies that evaluate pollutant effects under realistic multi-stressor scenarios. This study investigated the biochemical effects of octinoxate (also known as ethylhexyl methoxycinnamate, EHMC), a widely used organic UV filter, on the sea urchin Paracentrotus lividus under environmentally relevant conditions. A 28-day laboratory exposure was conducted using three EHMC concentrations (50, 500, and 5000 ng/L) under control conditions (17 °C, salinity 35) and climate change scenarios (21 °C, salinity 40). Multiple biomarkers were analysed, including metabolic activity, antioxidant and biotransformation responses, redox balance, cellular damage, and neurotoxicity. Results showed that the biochemical responses of P. lividus were significantly influenced by environmental conditions. Combined exposure to EHMC and elevated temperature (21 °C) induced marked oxidative stress, metabolic alterations, and shifts in detoxification responses. These effects were less pronounced under increased salinity, though still detectable. The present findings emphasize the heightened vulnerability of marine invertebrates to chemical pollutants under climate stress. Furthermore, the present study highlights the importance of integrating multiple stressors into ecotoxicological assessments and supports the use of bioindicator species, such as P. lividus, for more realistic environmental risk evaluations. Given that UV filters remain understudied contaminants and that data on their effects in echinoderms are still almost nonexistent, this work provides a timely contribution and highlights a critical knowledge gap that warrants urgent scientific attention.
{"title":"First evidence of climate-driven modulation of octinoxate toxicity in the sea urchin Paracentrotus lividus","authors":"Dinis Costa , Diana Bordalo , Marta Cunha , Amadeu M.V.M. Soares , Susana Carvalho , Rosa Freitas","doi":"10.1016/j.marenvres.2026.107847","DOIUrl":"10.1016/j.marenvres.2026.107847","url":null,"abstract":"<div><div>Although the use of ultraviolet (UV) filters in personal care products is steadily increasing, their ecological consequences remain poorly characterized despite evidence of persistence and bioaccumulation in marine systems. In parallel, climate change stressors such as rising temperatures and fluctuations in salinity are known to modulate the toxicity of contaminants and the physiological tolerance of marine organisms. The combined action of these factors can intensify biological stress, highlighting the need for studies that evaluate pollutant effects under realistic multi-stressor scenarios. This study investigated the biochemical effects of octinoxate (also known as ethylhexyl methoxycinnamate, EHMC), a widely used organic UV filter, on the sea urchin <em>Paracentrotus lividus</em> under environmentally relevant conditions. A 28-day laboratory exposure was conducted using three EHMC concentrations (50, 500, and 5000 ng/L) under control conditions (17 °C, salinity 35) and climate change scenarios (21 °C, salinity 40). Multiple biomarkers were analysed, including metabolic activity, antioxidant and biotransformation responses, redox balance, cellular damage, and neurotoxicity. Results showed that the biochemical responses of <em>P. lividus</em> were significantly influenced by environmental conditions. Combined exposure to EHMC and elevated temperature (21 °C) induced marked oxidative stress, metabolic alterations, and shifts in detoxification responses. These effects were less pronounced under increased salinity, though still detectable. The present findings emphasize the heightened vulnerability of marine invertebrates to chemical pollutants under climate stress. Furthermore, the present study highlights the importance of integrating multiple stressors into ecotoxicological assessments and supports the use of bioindicator species, such as <em>P. lividus</em>, for more realistic environmental risk evaluations. Given that UV filters remain understudied contaminants and that data on their effects in echinoderms are still almost nonexistent, this work provides a timely contribution and highlights a critical knowledge gap that warrants urgent scientific attention.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107847"},"PeriodicalIF":3.2,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145998633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents the first comprehensive, year-long assessment of free-living marine nematode assemblages inhabiting Cystoseira-dominated rocky substrates along the Rimel coast (Bizerte, Tunisia). Monthly sampling was conducted from March 2021 to February 2022 to explore both the taxonomic composition and functional trait dynamics of nematodes in response to temporal changes of the environmental conditions. A total of 50 species belonging to 38 genera and 18 families were identified, with Chromadoridae and Linhomoeidae being the most species-rich families. Despite the persistence of a core nematode assemblage, notable temporal changes were observed in both species-rich families and trait composition, particularly during spring (March–May) and summer (June–September) months. Multivariate analyses (nMDS, cluster analysis, and SIMPER) revealed distinct seasonal groupings, with brief periods of ecological turnover detected in April–May and June–July corresponding to short temporal windows during which nematode assemblages undergo rapid compositional and functional change. Functional traits, including feeding groups, tail and amphidial shapes, adult size, and c–p life-history strategies, exhibited significant temporal reorganization, corresponding to seasonally shifts, emergence, or decline of specific traits over time. Opportunistic traits (e.g., cp-2, non-selective deposit (1B) feeders, elongated tails, pocket and spiral amphids) were dominant during spring (April–May) and early autumn (September). In contrast, long-lived, stress-sensitive groups (cp-5) were not present. Although abiotic variables such as temperature, salinity, and oxygen displayed a strong temporal variability, no direct linear correlations with nematode diversity were observed, suggesting that assemblages’ dynamics are shaped by other and complex factors such as macroalgae structure, food sources availability, and colonization processes.
{"title":"Temporal shifts in diversity and functional traits of free-living nematode associated to Cystoseira","authors":"Amel Hannachi , Mohamed Allouche , Ahmed Nasri , Badreddine Sellami , Hamouda Beyrem , Ezzeddine Mahmoudi , Cristina Gambi , Roberto Danovaro","doi":"10.1016/j.marenvres.2026.107846","DOIUrl":"10.1016/j.marenvres.2026.107846","url":null,"abstract":"<div><div>This study presents the first comprehensive, year-long assessment of free-living marine nematode assemblages inhabiting Cystoseira-dominated rocky substrates along the Rimel coast (Bizerte, Tunisia). Monthly sampling was conducted from March 2021 to February 2022 to explore both the taxonomic composition and functional trait dynamics of nematodes in response to temporal changes of the environmental conditions. A total of 50 species belonging to 38 genera and 18 families were identified, with <em>Chromadoridae</em> and <em>Linhomoeidae</em> being the most species-rich families. Despite the persistence of a core nematode assemblage, notable temporal changes were observed in both species-rich families and trait composition, particularly during spring (March–May) and summer (June–September) months. Multivariate analyses (nMDS, cluster analysis, and SIMPER) revealed distinct seasonal groupings, with brief periods of ecological turnover detected in April–May and June–July corresponding to short temporal windows during which nematode assemblages undergo rapid compositional and functional change. Functional traits, including feeding groups, tail and amphidial shapes, adult size, and c–p life-history strategies, exhibited significant temporal reorganization, corresponding to seasonally shifts, emergence, or decline of specific traits over time. Opportunistic traits (e.g., cp-2, non-selective deposit (1B) feeders, elongated tails, pocket and spiral amphids) were dominant during spring (April–May) and early autumn (September). In contrast, long-lived, stress-sensitive groups (cp-5) were not present. Although abiotic variables such as temperature, salinity, and oxygen displayed a strong temporal variability, no direct linear correlations with nematode diversity were observed, suggesting that assemblages’ dynamics are shaped by other and complex factors such as macroalgae structure, food sources availability, and colonization processes.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107846"},"PeriodicalIF":3.2,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-08DOI: 10.1016/j.marenvres.2026.107841
Xiaomei Shen , Yiguo Hong , Fei Ye , Jiapeng Wu , Yu Wang , Fen Guo , Hang Wan , Hongbin Liu
Seagrass meadows are crucial in marine blue carbon storage. However, in subtropical estuaries dominated by small-sized species, their carbon storage capacity tends to be underestimated, and the key drivers of organic carbon (Corg) variability remain poorly understood. To address these issues, we investigated the spatial patterns of blue carbon storage and sediment Corg sources in a subtropical estuarine meadow dominated by the small seagrass Halophila beccarii in the Yifengxi Estuary, China, and identified the primary environmental factors governing its spatial heterogeneity. Our results showed that although the living biomass carbon stock was relatively low (0.028 ± 0.017 Mg C ha−1), consistent with the pioneer traits of Halophila beccarii, the sediment carbon stock in the upper 1 m was substantial (82.41 ± 29.99 Mg C ha−1), with considerable spatial variability (33.57–125.29 Mg C ha−1). Sediment Corg served as a robust indicator of carbon storage, showing positive correlations with multiple carbon metrics. The observed positive correlation with higher salinity and moisture suggests that sediment Corg preferentially accumulates in low-energy, waterlogged environments. Stable carbon isotope analysis and Bayesian mixing model results showed that terrestrial sources constituted the largest proportion of sediment Corg (49.84 ± 23.57 %), followed by seagrass (26.83 ± 21.43 %) and phytoplankton-derived carbon (23.33 ± 19.98 %), with clear spatial and vertical variations. These patterns reflect the combined influence of terrestrial inputs and intrinsic ecological dynamics on the carbon sink function of the meadow. Our findings provide critical biogeochemical insights into the carbon sequestration role of this ecosystem and underscore the need for management strategies that mitigate terrestrial pressures, enhance autochthonous carbon, implement zonal management, and sustain long-term monitoring.
海草草甸对海洋蓝碳储存至关重要。然而，在以小型物种为主的亚热带河口，其碳储存能力往往被低估，有机碳（Corg）变异的关键驱动因素仍然知之甚少。为了解决这些问题，我们研究了宜丰溪河口小海草贝氏盐藻（Halophila beccarii）主导的亚热带河口草甸蓝碳储量和沉积物碳源的空间格局，并确定了影响其空间异质性的主要环境因子。结果表明，虽然生物碳储量相对较低（0.028±0.017 Mg C ha-1），符合贝氏嗜盐菌的先行者特征，但上层1 m沉积物碳储量较大（82.41±29.99 Mg C ha-1），且空间变异较大（33.57 ~ 125.29 Mg C ha-1）。沉积物碳储量是碳储量的可靠指标，与多个碳指标呈正相关。观测到的高盐度和高湿度正相关表明，沉积物更倾向于在低能量、涝渍环境中积累。稳定碳同位素分析和贝叶斯混合模型结果表明，陆源碳占比最大（49.84±23.57%），其次是海草碳（26.83±21.43%）和浮游植物碳（23.33±19.98%），且空间和垂直变化明显。这些模式反映了陆地输入和内在生态动态对草甸碳汇功能的综合影响。我们的研究结果为该生态系统的碳固存作用提供了重要的生物地球化学见解，并强调了减轻陆地压力、增加原生碳、实施地带性管理和维持长期监测的管理策略的必要性。
{"title":"Factors affecting spatial variability in organic carbon storage and sources in an intertidal Halophila beccarii seagrass meadow of the Yifengxi Estuary, Southern China","authors":"Xiaomei Shen , Yiguo Hong , Fei Ye , Jiapeng Wu , Yu Wang , Fen Guo , Hang Wan , Hongbin Liu","doi":"10.1016/j.marenvres.2026.107841","DOIUrl":"10.1016/j.marenvres.2026.107841","url":null,"abstract":"<div><div>Seagrass meadows are crucial in marine blue carbon storage. However, in subtropical estuaries dominated by small-sized species, their carbon storage capacity tends to be underestimated, and the key drivers of organic carbon (C<sub>org</sub>) variability remain poorly understood. To address these issues, we investigated the spatial patterns of blue carbon storage and sediment C<sub>org</sub> sources in a subtropical estuarine meadow dominated by the small seagrass Halophila beccarii in the Yifengxi Estuary, China, and identified the primary environmental factors governing its spatial heterogeneity. Our results showed that although the living biomass carbon stock was relatively low (0.028 ± 0.017 Mg C ha<sup>−1</sup>), consistent with the pioneer traits of Halophila beccarii, the sediment carbon stock in the upper 1 m was substantial (82.41 ± 29.99 Mg C ha<sup>−1</sup>), with considerable spatial variability (33.57–125.29 Mg C ha<sup>−1</sup>). Sediment C<sub>org</sub> served as a robust indicator of carbon storage, showing positive correlations with multiple carbon metrics. The observed positive correlation with higher salinity and moisture suggests that sediment C<sub>org</sub> preferentially accumulates in low-energy, waterlogged environments. Stable carbon isotope analysis and Bayesian mixing model results showed that terrestrial sources constituted the largest proportion of sediment C<sub>org</sub> (49.84 ± 23.57 %), followed by seagrass (26.83 ± 21.43 %) and phytoplankton-derived carbon (23.33 ± 19.98 %), with clear spatial and vertical variations. These patterns reflect the combined influence of terrestrial inputs and intrinsic ecological dynamics on the carbon sink function of the meadow. Our findings provide critical biogeochemical insights into the carbon sequestration role of this ecosystem and underscore the need for management strategies that mitigate terrestrial pressures, enhance autochthonous carbon, implement zonal management, and sustain long-term monitoring.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107841"},"PeriodicalIF":3.2,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146010821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.marenvres.2026.107844
Hilmar Hinz , Maria del Mar Gil , Paula Anglada , José Maria Disdier , Olga Reñones , Gaetano Catanese , Julia Castro-Fernández , Antoni Sureda , Amalia Grau , Adam Gouraguine , Joan Moranta
Macrophyte habitats are key for juvenile fish survival in coastal littoral zones, yet they are increasingly degraded by human activities. While macrophytes offer both shelter and food, their protective function may be context-dependent, particularly in relation to predator abundance, which varies with fishing pressure and protection. In protected areas, where predator densities are higher, juvenile fish may face increased risk and rely more on complex habitats for refuge. Despite the potential benefits of structural complexity, studies on its effects on juvenile fish growth, condition, stress, and mortality remain limited.
This study tested the influence of macrophyte complexity on two Mediterranean fish, Symphodus ocellatus and Diplodus vulgaris, selected for their contrasting habitat preferences, under laboratory conditions. We hypothesized that juveniles would show improved growth, condition, and survival in complex habitats, especially under predator presence.
Results revealed species-specific responses. S. ocellatus, contrary to expectations, exhibited a slight reduction in body size, likely due to stress-induced physiological changes. However, this size loss was mitigated in structurally complex habitats. Mortality was also lowest in the highest complexity treatment. In contrast, D. vulgaris showed consistent fast growth across treatments, with only tentative effects of habitat complexity. For this species predator presence had a significant negative effect on weight gain in the unvegetated control treatment compared to the high complexity habitat treatment. Biochemical stress indicators supported these patterns. Elevated catalase activity in structurally complex habitats under predator presence, observed in both species, suggests a habitat-mediated physiological stress response. In contrast, the absence of significant differences in superoxide dismutase activity or RNA:DNA ratios across simpler habitats may indicate that stress levels exceeded physiological response limits, resulting in dampened or exhausted enzymatic responses. Circumstantial evidence for this interpretation is provided by the elevated mortality observed in S. ocellatus in no-habitat control treatments and the reduced weight gain in D. vulgaris under predator presence in the same habitat.
{"title":"The influence of algae habitat refuge complexity on juvenile fish growth, condition, and survival under the presence or absence of predators","authors":"Hilmar Hinz , Maria del Mar Gil , Paula Anglada , José Maria Disdier , Olga Reñones , Gaetano Catanese , Julia Castro-Fernández , Antoni Sureda , Amalia Grau , Adam Gouraguine , Joan Moranta","doi":"10.1016/j.marenvres.2026.107844","DOIUrl":"10.1016/j.marenvres.2026.107844","url":null,"abstract":"<div><div>Macrophyte habitats are key for juvenile fish survival in coastal littoral zones, yet they are increasingly degraded by human activities. While macrophytes offer both shelter and food, their protective function may be context-dependent, particularly in relation to predator abundance, which varies with fishing pressure and protection. In protected areas, where predator densities are higher, juvenile fish may face increased risk and rely more on complex habitats for refuge. Despite the potential benefits of structural complexity, studies on its effects on juvenile fish growth, condition, stress, and mortality remain limited.</div><div>This study tested the influence of macrophyte complexity on two Mediterranean fish, <em>Symphodus ocellatus</em> and <em>Diplodus vulgaris</em>, selected for their contrasting habitat preferences, under laboratory conditions. We hypothesized that juveniles would show improved growth, condition, and survival in complex habitats, especially under predator presence.</div><div>Results revealed species-specific responses. <em>S. ocellatus</em>, contrary to expectations, exhibited a slight reduction in body size, likely due to stress-induced physiological changes. However, this size loss was mitigated in structurally complex habitats. Mortality was also lowest in the highest complexity treatment. In contrast, <em>D. vulgaris</em> showed consistent fast growth across treatments, with only tentative effects of habitat complexity. For this species predator presence had a significant negative effect on weight gain in the unvegetated control treatment compared to the high complexity habitat treatment. Biochemical stress indicators supported these patterns. Elevated catalase activity in structurally complex habitats under predator presence, observed in both species, suggests a habitat-mediated physiological stress response. In contrast, the absence of significant differences in superoxide dismutase activity or RNA:DNA ratios across simpler habitats may indicate that stress levels exceeded physiological response limits, resulting in dampened or exhausted enzymatic responses. Circumstantial evidence for this interpretation is provided by the elevated mortality observed in <em>S. ocellatus</em> in no-habitat control treatments and the reduced weight gain in <em>D. vulgaris</em> under predator presence in the same habitat.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107844"},"PeriodicalIF":3.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145952361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.marenvres.2026.107838
Prachi Marathe , Anil Kumar Vijayan , B. Bikram Reddy , C.K. Sherin , V. Sudheesh
The study investigated the influence of upwelling-driven changes in physicochemical conditions and phytoplankton structure on the carbon (δ13C) and nitrogen (δ15N) stable isotope composition of particulate organic matter (POM) and major zooplankton groups (crustaceans, chaetognaths, and fish larvae) in the eastern Arabian Sea (EAS) during the 2018 summer monsoon (SM). Enhanced upwelling in the early and peak phases stimulated diatom-dominated blooms (73–91 %) resulting in elevated Chla concentrations (1.39 ± 1.09 and 3.94 ± 3.38 μg L−1). In contrast late-phase upwelling conditions were characterised by a deeper nitracline, leading to a shift towards smaller phytoplankton and dinoflagellates. The δ13C of POM (−21.8 ± 1.9 ‰) remained relatively enriched throughout, reflecting a sustained contribution from micro-phytoplankton. In contrast, δ15N of POM increased during late-monsoon (9.0 ± 2.5 ‰), consistent with nitrogen loss processes under low-oxygen conditions. Zooplankton δ13C and δ15N values exhibited similar phase-dependent pattern, indicating strong coupling with POM. Group-level isotopic signatures and trophic positions (TPs) revealed distinct feeding strategies: crustaceans exhibited herbivorous diets and lower TPs, whereas chaetognaths, and fish larvae occupied higher TPs indicative of carnivory. These findings underscore the dominant role of micro-phytoplankton (diatoms and dinoflagellates) in sustaining a shorter, classical food-chain during upwelling. This study provides the first regional-scale isotopic baseline for the EAS SM, with implications for isoscape development and trophodynamic modelling.
{"title":"Zooplankton trophic dynamics in response to upwelling phases in the eastern arabian sea: Insights from stable isotopes","authors":"Prachi Marathe , Anil Kumar Vijayan , B. Bikram Reddy , C.K. Sherin , V. Sudheesh","doi":"10.1016/j.marenvres.2026.107838","DOIUrl":"10.1016/j.marenvres.2026.107838","url":null,"abstract":"<div><div>The study investigated the influence of upwelling-driven changes in physicochemical conditions and phytoplankton structure on the carbon (δ<sup>13</sup>C) and nitrogen (δ<sup>15</sup>N) stable isotope composition of particulate organic matter (POM) and major zooplankton groups (crustaceans, chaetognaths, and fish larvae) in the eastern Arabian Sea (EAS) during the 2018 summer monsoon (SM). Enhanced upwelling in the early and peak phases stimulated diatom-dominated blooms (73–91 %) resulting in elevated Chl<em>a</em> concentrations (1.39 ± 1.09 and 3.94 ± 3.38 μg L<sup>−1</sup>). In contrast late-phase upwelling conditions were characterised by a deeper nitracline, leading to a shift towards smaller phytoplankton and dinoflagellates. The δ<sup>13</sup>C of POM (−21.8 ± 1.9 ‰) remained relatively enriched throughout, reflecting a sustained contribution from micro-phytoplankton. In contrast, δ<sup>15</sup>N of POM increased during late-monsoon (9.0 ± 2.5 ‰), consistent with nitrogen loss processes under low-oxygen conditions. Zooplankton δ<sup>13</sup>C and δ<sup>15</sup>N values exhibited similar phase-dependent pattern, indicating strong coupling with POM. Group-level isotopic signatures and trophic positions (TPs) revealed distinct feeding strategies: crustaceans exhibited herbivorous diets and lower TPs, whereas chaetognaths, and fish larvae occupied higher TPs indicative of carnivory. These findings underscore the dominant role of micro-phytoplankton (diatoms and dinoflagellates) in sustaining a shorter, classical food-chain during upwelling. This study provides the first regional-scale isotopic baseline for the EAS SM, with implications for isoscape development and trophodynamic modelling.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107838"},"PeriodicalIF":3.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phaeocystis globosa-forming blooms pose serious ecological and economic risks by releasing hemolytic toxins, inducing hypoxia, threatening fisheries, and even obstructing seawater intake in nuclear power plants. Rapid and reliable detection of this alga is therefore critical. Here, a rapid, sensitive, and quantitative visual detection method that is referred to as split aptamer–gold nanoparticle colorimetric assay (SAGCA) was established for P. globosa. For this purpose, a parent aptamer (PAP) (Pg-TA1) against P. globosa was first split into two segments (Pg-SP1 and Pg-SP2) followed by analyzing their synergistic binding efficiency. The results demonstrated that neither Pg-SP1 nor Pg-SP2 alone could recognize target cells. By contrast, Pg-SP1 and Pg-SP2 restored the binding ability comparable to the PAP when they were combined. Subsequently, the binding conditions of the split aptamers were optimized, and a SAGCA detection system based on the split aptamers was established. The detection limit of SAGCA was 2 cells mL−1, with a linear range of 1 × 101 cells mL−1–1 × 108 cells mL−1 (R2 = 0.965). SAGCA demonstrated good specificity and strong anti-interference effectiveness. The quantification results of SAGCA were substantially consistent with those from microscopic examination. SAGCA may be used as a good alternative to the microscopy-based detection method for P. globosa, and thus offers an efficient, low-cost way for monitoring other hazardous microalgae.
{"title":"A novel split aptamer–gold nanoparticle colorimetric assay for the rapid detection of Phaeocystis globosa","authors":"Xueyang Tian, Qianyu Liu, Siqi Cheng, Wenqing Chen, Chunyun Zhang, Yuanyuan Wang, Changlu Guo, Guofu Chen","doi":"10.1016/j.marenvres.2026.107835","DOIUrl":"10.1016/j.marenvres.2026.107835","url":null,"abstract":"<div><div><em>Phaeocystis globosa-</em>forming blooms pose serious ecological and economic risks by releasing hemolytic toxins, inducing hypoxia, threatening fisheries, and even obstructing seawater intake in nuclear power plants. Rapid and reliable detection of this alga is therefore critical. Here, a rapid, sensitive, and quantitative visual detection method that is referred to as split aptamer–gold nanoparticle colorimetric assay (SAGCA) was established for <em>P. globosa</em>. For this purpose, a parent aptamer (PAP) (Pg-TA1) against <em>P. globosa</em> was first split into two segments (Pg-SP1 and Pg-SP2) followed by analyzing their synergistic binding efficiency. The results demonstrated that neither Pg-SP1 nor Pg-SP2 alone could recognize target cells. By contrast, Pg-SP1 and Pg-SP2 restored the binding ability comparable to the PAP when they were combined. Subsequently, the binding conditions of the split aptamers were optimized, and a SAGCA detection system based on the split aptamers was established. The detection limit of SAGCA was 2 cells mL<sup>−1</sup>, with a linear range of 1 × 10<sup>1</sup> cells mL<sup>−1</sup>–1 × 10<sup>8</sup> cells mL<sup>−1</sup> (<em>R</em><sup><em>2</em></sup> = 0.965). SAGCA demonstrated good specificity and strong anti-interference effectiveness. The quantification results of SAGCA were substantially consistent with those from microscopic examination. SAGCA may be used as a good alternative to the microscopy-based detection method for <em>P. globosa</em>, and thus offers an efficient, low-cost way for monitoring other hazardous microalgae.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107835"},"PeriodicalIF":3.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.marenvres.2026.107832
A.M. Blázquez , A. Rodríguez-Pérez , J. Caicedo-Rodríguez , I. Montoya-Blázquez , J. Guillem
Coastal wetlands are the most common environments in the Spanish Mediterranean. They provide valuable information about past interactions between sea level fluctuations, climate variability and sediment dynamics, which could enable us to predict the future response of coastal systems to global climate change.
This study analyses the palaeoenvironmental evolution of the Moros Marsh (Western Mediterranean) during the Holocene, with the aim of assessing the impact of the MIS 1 marine transgression and climate change on the configuration of the wetland during this period. To achieve this goal, 347 samples extracted from four boreholes were studied from a sedimentological, micropalaeontological and chronological perspective.
The results show a thick alluvial unit at the base of all the boreholes, dated as Middle Holocene, on which brackish marsh facies developed, which later became freshwater. A barrier facies has been detected in the most coastal borehole (Moro 2), with a maximum Holocene transgression (MIS 1) dated around 5200 cal yr BP. The first flooding evidence appears in the innermost borehole (Moro 1) around 3562-3440 cal yr BP and continues to the present day, with episodes of oscillation in the water table related to climatic changes in the Northern Hemisphere. A low-salinity, low-energy environment is determined, with little marine influence and a powerful supply of fresh water from the aquifer.
This environment is the result of the interaction between eustatic and climatic factors. The former account for the formation of the lagoon system, and the latter are the main controllers of its subsequent evolution.
{"title":"Impact of Holocene marine transgression and climatic changes on the Moros marsh (western Mediterranean, Spain)","authors":"A.M. Blázquez , A. Rodríguez-Pérez , J. Caicedo-Rodríguez , I. Montoya-Blázquez , J. Guillem","doi":"10.1016/j.marenvres.2026.107832","DOIUrl":"10.1016/j.marenvres.2026.107832","url":null,"abstract":"<div><div>Coastal wetlands are the most common environments in the Spanish Mediterranean. They provide valuable information about past interactions between sea level fluctuations, climate variability and sediment dynamics, which could enable us to predict the future response of coastal systems to global climate change.</div><div>This study analyses the palaeoenvironmental evolution of the Moros Marsh (Western Mediterranean) during the Holocene, with the aim of assessing the impact of the MIS 1 marine transgression and climate change on the configuration of the wetland during this period. To achieve this goal, 347 samples extracted from four boreholes were studied from a sedimentological, micropalaeontological and chronological perspective.</div><div>The results show a thick alluvial unit at the base of all the boreholes, dated as Middle Holocene, on which brackish marsh facies developed, which later became freshwater. A barrier facies has been detected in the most coastal borehole (Moro 2), with a maximum Holocene transgression (MIS 1) dated around 5200 cal yr BP. The first flooding evidence appears in the innermost borehole (Moro 1) around 3562-3440 cal yr BP and continues to the present day, with episodes of oscillation in the water table related to climatic changes in the Northern Hemisphere. A low-salinity, low-energy environment is determined, with little marine influence and a powerful supply of fresh water from the aquifer.</div><div>This environment is the result of the interaction between eustatic and climatic factors. The former account for the formation of the lagoon system, and the latter are the main controllers of its subsequent evolution.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107832"},"PeriodicalIF":3.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-06DOI: 10.1016/j.marenvres.2026.107836
Zhengyu Qin , Zuofang Yao , Yuanle Pan , Fei Yang
Global warming and urbanization have greatly intensified the heat threats to urban residents. Marine cooling effect (MCE) is essential for mitigating urban heat threats in coastal cities, yet there is still big gap of understanding its seasonal dynamics and underlying drivers in subtropical nearshore zones. Taking the Guangxi Beibu Gulf as a case, this study combined multi-temporal Landsat 8 land surface temperature datasets with Spearman correlation, local spatial autocorrelation (LISA), and optimal-parameter geographical detector (OPGD) analyses to quantify MCE, which is indicated by marine cooling intensity (MCI) and marine cooling distance (MCD), and to dissect their spatiotemporal heterogeneity and driving mechanisms. Results reveal distinct seasonal changes regimes. MCI peaked in summer (up to 23.75 °C) and was lowest in autumn, while MCD reached its maximum inland extent in spring (750m). High intensity cooling consistently clustered around coastal port areas and dense gray-space urban core zones, whereas blue-space and green-space-rich zones exhibited weaker cooling. Gray space exerted a persistent positive influence on MCI across seasons (summer q > 0.55), while blue space extended MCD only in spring and green space generally shortened it. Landscape fragmentation (ED, LSI) weakened cooling in most seasons, underscoring the role of spatial continuity in facilitating MCE. Driver interactions varied by season. Blue-gray synergy produced the strongest nonlinear enhancement of MCI year-round (q > 0.60), indicating that mixed land-water configurations sharpen cooling contrasts at the land-sea interface. MCD propagation was governed in spring by blue-building coupling interactions (AI_BS × ABH, q = 0.34), in summer by gray-green coupling interactions (AI_IS × LPI_GS, q = 0.26), and in autumn by more and weaker balanced multi-factor effects. These findings highlight the seasonal shifts in how gray, blue, and green spaces individually and interactively regulate coastal thermal environments. The framework provides transferable metrics for diagnosing and optimizing blue-green-gray spatial patterns in climate adaptive coastal urban planning, with potential to maximize cooling benefits for densely built port cities in subtropical regions.
{"title":"Quantification of marine cooling effect and driving mechanism along Beibu Gulf coastal areas","authors":"Zhengyu Qin , Zuofang Yao , Yuanle Pan , Fei Yang","doi":"10.1016/j.marenvres.2026.107836","DOIUrl":"10.1016/j.marenvres.2026.107836","url":null,"abstract":"<div><div>Global warming and urbanization have greatly intensified the heat threats to urban residents. Marine cooling effect (MCE) is essential for mitigating urban heat threats in coastal cities, yet there is still big gap of understanding its seasonal dynamics and underlying drivers in subtropical nearshore zones. Taking the Guangxi Beibu Gulf as a case, this study combined multi-temporal Landsat 8 land surface temperature datasets with Spearman correlation, local spatial autocorrelation (LISA), and optimal-parameter geographical detector (OPGD) analyses to quantify MCE, which is indicated by marine cooling intensity (MCI) and marine cooling distance (MCD), and to dissect their spatiotemporal heterogeneity and driving mechanisms. Results reveal distinct seasonal changes regimes. MCI peaked in summer (up to 23.75 °C) and was lowest in autumn, while MCD reached its maximum inland extent in spring (750m). High intensity cooling consistently clustered around coastal port areas and dense gray-space urban core zones, whereas blue-space and green-space-rich zones exhibited weaker cooling. Gray space exerted a persistent positive influence on MCI across seasons (summer q > 0.55), while blue space extended MCD only in spring and green space generally shortened it. Landscape fragmentation (ED, LSI) weakened cooling in most seasons, underscoring the role of spatial continuity in facilitating MCE. Driver interactions varied by season. Blue-gray synergy produced the strongest nonlinear enhancement of MCI year-round (q > 0.60), indicating that mixed land-water configurations sharpen cooling contrasts at the land-sea interface. MCD propagation was governed in spring by blue-building coupling interactions (AI_BS × ABH, q = 0.34), in summer by gray-green coupling interactions (AI_IS × LPI_GS, q = 0.26), and in autumn by more and weaker balanced multi-factor effects. These findings highlight the seasonal shifts in how gray, blue, and green spaces individually and interactively regulate coastal thermal environments. The framework provides transferable metrics for diagnosing and optimizing blue-green-gray spatial patterns in climate adaptive coastal urban planning, with potential to maximize cooling benefits for densely built port cities in subtropical regions.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107836"},"PeriodicalIF":3.2,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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