Marine environmental research最新文献

{"title":"Human activities regulate the sources and composition pattern of organic matter in the coastal bays of the East China Sea during spring","authors":"Yangyang Li ,&nbsp;Kui Wang ,&nbsp;Kai Cai ,&nbsp;Yan Bai ,&nbsp;Xuan Zhang ,&nbsp;Xianqiang He ,&nbsp;Zixuan Min ,&nbsp;Xinwen Ning","doi":"10.1016/j.marenvres.2025.107818","DOIUrl":"10.1016/j.marenvres.2025.107818","url":null,"abstract":"<div><div>The sources and composition of organic matter (including particulate and dissolved organic matter (POM and DOM)) are typically influenced by both natural processes and human activities. However, few studies have combined stable isotopic signatures of POM with the optical characteristics of DOM to quantify the contribution of human activities to the sources and composition of organic matter in complex environments. To differentiate the contributions of natural processes and human activities to POM and DOM in the coastal bays of the East China Sea (ECS), stable carbon and nitrogen isotopes in POM, along with the optical properties of DOM, were analyzed. The results revealed that POM was primarily composed of soil organic matter (OM), phytoplankton OM and sewage OM. The findings indicated that human activities dominated the POM pool (58.08 ± 19.40 %), primarily through two pathways: (1) the part of phytoplankton POM supported by anthropogenic nutrients, and (2) the direct input of sewage-derived particles. Meanwhile, the DOM in these regions was primarily composed of terrestrial humic-like substances (C1), tryptophan-like components (C2) derived from the microbial degradation of sewage-derived particles, and untreated, directly discharged protein-like wastewater components (C3). The C2 and C3, collectively accounting for 66.9 ± 9.5 % of the total, indicated that the composition of the DOM pool was regulated by anthropogenic influences. This predominant anthropogenic influence was further corroborated by a clear land-sea gradient, evidenced by significant differences in stable isotopic (POM) and fluorescent signatures (DOM) between the coastal bays and offshore region. Furthermore, a significant positive correlation was observed between the nitrogen stable isotope in POM, a tracer for sewage, and the relative abundance of C2 (r = 0.31, <em>p</em> &lt; 0.05). This correlation suggested a common anthropogenic source and implied that a portion of the sewage-derived DOM might be produced through the degradation of labile sewage-derived POM. This suggests a potential transformation linkage between the POM and DOM pools, likely mediated by microbial activity. These findings provide key insights into the sources and composition of organic matter in coastal bays of ECS, contributing to a better understanding of how human factors affect coastal ecosystems.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107818"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145850412","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}

{"title":"Effect of anthropogenic electromagnetic fields used for subsurface oil and gas exploration (controlled-source electromagnetics, CSEM) on the fertilization success and embryonic development of Atlantic cod (Gadus morhua)","authors":"Gauthier F. Lorillard ,&nbsp;Caroline M.F. Durif ,&nbsp;Alessandro Cresci ,&nbsp;Anne Berit Skiftesvik ,&nbsp;Howard I. Browman ,&nbsp;Reidun Bjelland ,&nbsp;Anders Thorsen ,&nbsp;Guosong Zhang ,&nbsp;Lise Doksæter Sivle ,&nbsp;Prescilla Perrichon","doi":"10.1016/j.marenvres.2025.107811","DOIUrl":"10.1016/j.marenvres.2025.107811","url":null,"abstract":"<div><div>Surveys that rely on Controlled Source Electromagnetics (CSEM) explore the seabed for hydrocarbon deposits. These surveys can overlap temporally and spatially with spawning areas for Atlantic cod (<em>Gadus morhua</em>). Cod eggs are planktonic and develop in the water column and therefore may be exposed to the electromagnetic fields (EMFs) generated by CSEM. We replicated equivalent EMFs in the laboratory and tested their potential effects on cod reproduction. Two experiments were conducted: 1) 15-min. single EMF exposure of male cod, followed by assessment of sperm motility and subsequent monitoring of offspring development; 2) 15-min, single EMF exposure of fertilized eggs, followed by monitoring of embryonic development. Three EMF intensities, corresponding to 30 [50.3 μT], 100 [12.6 μT] and 1000 m [0.126 μT] between the organism and the source, were applied in each experiment. Exposure to EMFs had no effect on size, morphology or cardiac function in any of the experiments. Sperm velocities increased slightly, by 0.5 % in curvilinear path and 0.6 % in average path length post-exposure. However, the functional significance of this effect is likely negligible.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107811"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145863220","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}

{"title":"Temporal shifts in diversity and functional traits of free-living nematode associated to Cystoseira","authors":"Amel Hannachi ,&nbsp;Mohamed Allouche ,&nbsp;Ahmed Nasri ,&nbsp;Badreddine Sellami ,&nbsp;Hamouda Beyrem ,&nbsp;Ezzeddine Mahmoudi ,&nbsp;Cristina Gambi ,&nbsp;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":"2026-03-01","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}

{"title":"Marine heatwaves disrupt germination and seedling physiology in Zostera marina","authors":"Riccardo Pieraccini ,&nbsp;Ann Vanreusel ,&nbsp;Nico Koedam ,&nbsp;Chiara Marulli ,&nbsp;Tobias Dolch ,&nbsp;Tom Van der Stocken","doi":"10.1016/j.marenvres.2025.107789","DOIUrl":"10.1016/j.marenvres.2025.107789","url":null,"abstract":"<div><div>Marine heatwaves (MHWs) are intensifying with climate change, posing a growing threat to the resilience of coastal marine ecosystems, such as seagrasses. While MHW impacts on adult seagrasses are increasingly studied, their effects on early developmental stages remain unexplored. This represents a critical knowledge gap, as recruitment success is essential for long-term population persistence, particularly in degraded or restored meadows.</div><div>Here, we exposed <em>Zostera marina</em> seeds to three realistic MHW categories (moderate, strong, and severe) during the natural spring germination period. We assessed how thermal stress influences germination dynamics, seedling morphology, and physiological performance.</div><div>Germination exhibited a non-linear response to MHW intensity. Moderate MHW (Category I) significantly delayed germination and reduced emergence, while strong MHW (Category II) unexpectedly enhanced germination but induced a shoot–root growth imbalance, with greater shoot than root development. Severe MHW (Category III) suppressed pigment concentrations and electron transport rates, suggesting reduced photoprotection and probable PSII damage.</div><div>These carry-over effects reveal a narrow thermal window for successful seedling development, where temperatures only slightly above the baseline affect germination, early growth stages and pigment composition, making early life stages a physiological bottleneck under climate extremes. By identifying critical thresholds and associated developmental trade-offs, our study advances understanding of how early-stage sensitivity can constrain population recovery and facilitates integration of seed-based responses into predictive frameworks of seagrass resilience and coastal habitat stability in a warming ocean.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107789"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145819864","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}

{"title":"Temporal shifts in stable isotopes tracks climate variability in a benthic foraging marine predator","authors":"Saia N. Bartes ,&nbsp;Hilary Stuart-Williams ,&nbsp;John P.Y. Arnould","doi":"10.1016/j.marenvres.2025.107813","DOIUrl":"10.1016/j.marenvres.2025.107813","url":null,"abstract":"<div><div>Understanding how top-order predators respond to environmental variability is essential for predicting the resilience of marine ecosystems under climate change. We investigated long-term trophic niche dynamics in 115 adult female Australian fur seals (<em>Arctocephalus pusillus doriferus</em>) by analysing δ¹³C and δ¹⁵N values from 4187 whiskers subsamples collected between 2010 and 2023. Using wavelet analysis derived growth rates, we temporally aligned isotopic data over a 22-yer period and applied trophic niche metrics to quantify individual specialisation and population-level variation. Isotopic trends revealed a consistent increase in δ¹³C and decrease in δ¹⁵N values, with significant associations to lagged values of broad-scale climate indices (SOI, IOD, SAM). However, these environmental drivers did not explain niche width and individual specialisation. A marked shift was observed after-2015 in the niche dynamics coinciding with the strongest El Nino event for the area. These changes suggest that individuals broadened their diets within a narrowing resource base, potentially in response to heightened intra-specific competition, altered prey availability or changes in the environmental baseline. Our findings highlight the importance of integrating long-term isotopic data with niche metrics to detect subtle ecological responses to climate variability. While AUFS females display some buffering capacity, continued environmental change may challenge their foraging flexibility and impact population resilience.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107813"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145896633","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}

{"title":"Sperm whale acoustic ecology around two sub-Antarctic islands","authors":"Fannie W. Shabangu","doi":"10.1016/j.marenvres.2025.107805","DOIUrl":"10.1016/j.marenvres.2025.107805","url":null,"abstract":"<div><div>Sperm whales are cosmopolitan in nature, but very little is known about their occurrence in the sub-Antarctic region. This study aimed to investigate the acoustic occurrence of sperm whales relative to environmental conditions and underwater noise around two sub-Antarctic Prince Edward Islands (PEIs) using passive acoustic monitoring data collected between early 2021 and early 2023. Sperm whale clicks were detected continuously throughout the study period with high presence of calls in February through August, highlighting the PEIs as an essential habitat with sufficient year-round prey for this species. Moreover, the February through August peak occurrence corresponds to the migration period of males from Antarctica to the low latitudes for mating. Diel vocalizing pattern revealed high nighttime vocalization that varied slightly between seasons. Wind speed was classified by the random forest model as the most important predictor of sperm whale acoustic occurrence, indicating possible masking and attenuation of whale signals by wind-induced noise and wind-induced air bubbles respectively. Generalized additive model showed that the probability of detecting sperm whale clicks decreased with increasing high frequency band (25001–48000 Hz) noise, reflecting a significant influence of the high frequency noise on this species’ ecology. This is the first study to document the acoustic presence of sperm whales around the sub-Antarctic PEIs, showcasing the capability of bioacoustics method to effectively study marine mammals that are rarely sighted. Sperm whales should be considered in the spatial management and conservation plans of the PEIs given their year-round presence in this region.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107805"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789441","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}

{"title":"Assessment of microbial community changes in seawater of marine cage- culture large yellow croaker (Larimichthys crocea) farms","authors":"Tumusenge Daniel,&nbsp;Chenchen Hu,&nbsp;Shuaiqing Wang,&nbsp;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":"2026-03-01","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}

{"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 ,&nbsp;Yiguo Hong ,&nbsp;Fei Ye ,&nbsp;Jiapeng Wu ,&nbsp;Yu Wang ,&nbsp;Fen Guo ,&nbsp;Hang Wan ,&nbsp;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_org) variability remain poorly understood. To address these issues, we investigated the spatial patterns of blue carbon storage and sediment C_org 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 C_org 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_org 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_org (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":"2026-03-01","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}

{"title":"Zooplankton trophic dynamics in response to upwelling phases in the eastern arabian sea: Insights from stable isotopes","authors":"Prachi Marathe ,&nbsp;Anil Kumar Vijayan ,&nbsp;B. Bikram Reddy ,&nbsp;C.K. Sherin ,&nbsp;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 (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 Chl<em>a</em> 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.</div></div>","PeriodicalId":18204,"journal":{"name":"Marine environmental research","volume":"215 ","pages":"Article 107838"},"PeriodicalIF":3.2,"publicationDate":"2026-03-01","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}

{"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 ,&nbsp;Maria del Mar Gil ,&nbsp;Paula Anglada ,&nbsp;José Maria Disdier ,&nbsp;Olga Reñones ,&nbsp;Gaetano Catanese ,&nbsp;Julia Castro-Fernández ,&nbsp;Antoni Sureda ,&nbsp;Amalia Grau ,&nbsp;Adam Gouraguine ,&nbsp;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":"2026-03-01","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}