Marine Environmental Research[JOURNAL]
Sun
200 papers
Crossing from shallow inshore to deep continental shelf habitats: Benthic-pelagic coupling and trophic position of the Lane snapper, Lutjanus synagris, in a tropical seascape.
Bastos RF, Garcia AM, Frédou T … +5 more , Le Loc'h F, Yogui GT, Rezende SM, Maida M, Ferreira BP
Mar Environ Res · 2026 Jul · PMID 42081858 · Publisher ↗
Trophic connectivity, or trophic subsidies, refers to the transfer of matter, energy and nutrients across both horizontal and vertical gradients in aquatic habitats. Seascape depth plays a critical role in regulating foo...
Trophic connectivity, or trophic subsidies, refers to the transfer of matter, energy and nutrients across both horizontal and vertical gradients in aquatic habitats. Seascape depth plays a critical role in regulating food webs and the coupling between benthic and pelagic pathways. On tropical shallow continental shelves (<30 m), benthic primary production often exceeds pelagic primary production due to the absence of light limitations. Conversely, mesophotic conditions on the outer continental shelf restrict light penetration, thereby limiting benthic production. Furthermore, oceanographic processes and local topography along the continental shelf and slope may enhance pelagic production near the shelf break and submarine canyons through upwelling. In this study, we investigated the role of the Lane snapper (Lutjanus synagris) in mediating benthic-pelagic coupling across a range of habitats, including coastal shallow seagrass meadows, mangroves, coral reefs, and continental shelf gradient. We employed stable isotope (δC, δN) of L. synagris, basal sources and consumers from both benthic and pelagic pathways to model trophic position (TP) and assess trophic support. TP were consistent regardless of whether basal sources or consumers served as baselines, although the model based on basal consumers produced narrower credible intervals. TP increased from inshore to continental shelf habitats, primarily reflecting increases in fish size; however, no significant differences were observed between shallow and mesophotic shelf areas. Mixing models based on basal consumer baselines further revealed that in seagrass meadows, coastal reefs, and mesophotic shelf habitats, the Lane snapper derives trophic support from both benthic and pelagic sources, whereas benthic support predominates in mangroves and shallow shelf habitats. Pelagic support showed a positive correlation with depth across the continental shelf, which could be related to physical and geological processes, such as upwelling near the shelf break and through submarine canyons, that augment pelagic subsidies, particularly when benthic production is limited at greater depths. In summary, our findings underscore the significance of both physical geological and biological drivers in shaping the trophic dynamics and ontogenetic habitat use of L. synagris. These insights emphasize the necessity of sustaining spatial connectivity among marine protected areas to maintain robust trophic interactions and overall ecosystem health.
Thermal threshold triggers hepatic immune reprogramming and oxidative exhaustion in large yellow croaker Larimichthys crocea.
Zheng C, Zeb R, Zheng R … +5 more , Fang C, You J, Liu K, Lin H, Bo J
Mar Environ Res · 2026 Jul · PMID 42070543 · Publisher ↗
Thermal effluents from coastal nuclear power plants (NPPs) typically raise near-field seawater temperatures by 2-4 °C for several hours to days, imposing thermal stress on local marine biota. This study investigates the...
Thermal effluents from coastal nuclear power plants (NPPs) typically raise near-field seawater temperatures by 2-4 °C for several hours to days, imposing thermal stress on local marine biota. This study investigates the biochemical and molecular responses of juvenile large yellow croaker Larimichthys crocea to acute thermal stress, simulating the thermal discharges from coastal NPPs. Fish were exposed to 28 °C (control), 29 °C, 30 °C, and 32 °C, with sampling conducted at 24 h and 96 h. At 32 °C, all fish died within 48 h, while exposure to 29 °C and 30 °C for 96 h induced oxidative stress in the liver, marked by elevated lipid peroxidation and altered antioxidant enzyme activities. Transcriptomic analysis showed a significant intensification of immune responses after 96 h compared to 24 h at both 29 °C and 30 °C. Notably, immune response adaptation occurred at 29 °C, whereas at 30 °C, immune-related pathways shifted from pro-inflammatory activation to broad transcriptional suppression as the temperature approached the species' upper thermal limit. These findings highlight the narrow thermal tolerance of L. crocea, provide insights into the risks of thermal pollution from NPPs, and emphasize the need for improved coastal aquaculture management to address the impacts of climate change and ocean warming.
No apparent impact of moderate temperature increase on growth and fecundity in the sea star Asterias rubens.
Le Bourg B, Keraudran M
Mar Environ Res · 2026 Jul · PMID 42068866 · Publisher ↗
Sea stars are considered as both keystone predators and pests for shellfish fisheries and aquaculture. Recurrent outbreaks after mild winters in temperate ecosystems suggest that the reproductive success of sea stars may...
Sea stars are considered as both keystone predators and pests for shellfish fisheries and aquaculture. Recurrent outbreaks after mild winters in temperate ecosystems suggest that the reproductive success of sea stars may be positively impacted by rising ocean temperatures induced by climate change, although previous studies have shown that the strongest projected increase of temperature may be detrimental to them. The impact of a moderate rise of ocean temperature on growth and fecundity of the sea star Asterias rubens was investigated. Males and females were exposed for 6 months either to monthly temperatures from the 1995-2014 periods or to these temperatures elevated by 1.5 °C, as projected at the end of the century by the "middle of the road" scenario of greenhouse gas emissions. Growth (measured as the change in arm length and body weight between the beginning and the end of the experiment), pyloric caeca weight, gonad weight, pyloric index, gonadosomatic index, gamete concentration (number of oocytes or sperm per gram of gonad), fecundity (number of oocytes or sperm per individual) and oocyte shape (volume and sphericity) were assessed at the end of the experimental period. No effect of temperature was observed for any of the investigated variables. Overall, these results indicate that A. rubens may not be impacted by the moderate increases of temperature that might occur if policies promoting the reduction of greenhouse gas emissions would be implemented.
Dual carbon isotope constraints on dissolved carbon cycling in an integrated aquaculture bay: A case study of Sanggou Bay, China.
Liu Y, Wang X, Yu J … +2 more , Wu W, Zhang J
Mar Environ Res · 2026 Jul · PMID 42068865 · Publisher ↗
Coastal aquaculture significantly alters marine carbon cycling, yet the underlying source and transformation processes remain poorly understood. This study investigated the spatiotemporal dynamics, drivers, and sources o...
Coastal aquaculture significantly alters marine carbon cycling, yet the underlying source and transformation processes remain poorly understood. This study investigated the spatiotemporal dynamics, drivers, and sources of dissolved organic and inorganic carbon (DOC and DIC) in Sanggou Bay, a typical integrated macroalgae-shellfish aquaculture system in northern China. By employing isotope ratio mass spectrometry (IRMS) and other analytical instruments, we characterized concentrations and stable carbon isotope signatures (δC-DOC and δC-DIC). These data were integrated with a Bayesian MixSIAR model and deviation analysis (deviations in ΔDIC/DIC and ΔδC from conservative mixing) to elucidate the spatiotemporal dynamics, sources, and driving factors of dissolved carbon in the study area. The results indicate that: DOC concentrations peaked in macroalgae areas, whereas DIC reached its maximum in shellfish areas. MixSIAR modeling identified macroalgae and phytoplankton as the predominant DOC sources (63-83%), with negligible terrestrial input (<1%). Deviation analysis further revealed that macroalgae exerted a more pronounced influence on dissolved carbon dynamics than shellfish. Furthermore, isotopic evidence confirmed the rapid microbial utilization of macroalgae-derived DOC and demonstrated a significant seasonal reversal in the carbon source-sink role of shellfish aquaculture. These findings demonstrate that intensive aquaculture fundamentally alters coastal dissolved carbon dynamics, providing critical insights into marine carbon sequestration mechanisms.
Climate change is likely to negatively affect a marine apex predator (Steno bredanensis, Cetacea) and its prey on the coast of Brazil.
do Nascimento Ferreira J, Vale MM, Maricato G … +6 more , Maciel I, Lodi L, Daura-Jorge FG, Milmann L, Marcondes MCC, Tardin RH
Mar Environ Res · 2026 Jul · PMID 42066413 · Publisher ↗
Climate change alters marine environments, affecting temperature, oxygen levels, and acidity, prompting species to relocate to suitable areas. Understanding these shifts is vital for top predators like cetaceans, crucial...
Climate change alters marine environments, affecting temperature, oxygen levels, and acidity, prompting species to relocate to suitable areas. Understanding these shifts is vital for top predators like cetaceans, crucial for marine ecosystem regulation. We mapped the highly suitable environments for the rough-toothed dolphin (Steno bredanensis)-considering its limited study in Brazil-and three of its prey: the largehead hairtail (Trichiurus lepturus), the lebranche mullet (Mugil liza), and the white mullet (Mugil curema). We used five modeling algorithms and 4-7 environmental variables to create ecological niche models, transformed into binary maps for interpretation. We also classified and overlaid Brazilian Marine Protected Areas (MPAs) with the rough-toothed dolphin's highly suitable environments using the MPA Guide. Under future climate change, we predicted an 8.7 to 13.6% reduction in highly suitable areas for the rough-toothed dolphins in Brazil, mainly in the country's Northern and Northeastern coast. We predicted a small loss of highly suitable areas for mullet species (3 to 7%) and a moderate loss for the largehead hairtail (31 to 35%). To date, only 3.7% of rough-toothed dolphin's highly suitable areas overlap with Brazilian MPAs, mainly in low-protection protected areas. Most highly suitable areas remain unprotected, and this situation is projected to persist under future climate scenarios. Our study reveals a significant range loss for rough-toothed dolphins and their prey in Northern and Northeastern Brazil because of climate change. Existing MPAs are inadequate, showing an urgent need for expansion.
Identifying lineages of cold-tolerant rotifers in a Korean brackish lagoon using eDNA metabarcoding, morphology, and life-history traits.
Shim BS, Lee JS, Park HG … +1 more , Lee YH
Mar Environ Res · 2026 Jul · PMID 42066412 · Publisher ↗
Environmental DNA (eDNA) metabarcoding has become a powerful tool for uncovering cryptic biodiversity in brackish ecosystems. However, ecological and physiological characterization of newly detected taxa remains limited....
Environmental DNA (eDNA) metabarcoding has become a powerful tool for uncovering cryptic biodiversity in brackish ecosystems. However, ecological and physiological characterization of newly detected taxa remains limited. In this study, we combined eDNA-based community profiling, morphological analysis, and in vivo life-parameter experiments to resolve the lineages and cold-adaptive traits of two rotifer strains (H-SL and H-US) collected from Hwajinpo Lagoon, East Sea, Korea. eDNA surveys revealed a rotifer-rich microfaunal community, particularly in Hwajinpo, where unidentified Brachionus taxa were dominant. Targeted isolation and subsequent analyses indicated that H-SL and H-US correspond to large- and small-type Brachionus lineages, respectively, each exhibiting distinct morphological traits and molecular affiliations with known species complexes. Life-parameter experiments revealed that H-SL maintained reproductive activity and population growth under cold conditions (16-20 °C), suggesting cold tolerance and demographic stability, whereas H-US exhibited a warm-adapted, fast-growing strategy with limited persistence. These findings underscore the value of combining eDNA detection with integrative biological characterization to reveal functional diversity in transitional ecosystems and identify candidate strains for cold-water aquaculture.
Environmental DNA metabarcoding reveals spatial patterns of benthic molluscan diversity across island reefs in the South China Sea.
Zhang H, Si M, He M
Mar Environ Res · 2026 Jul · PMID 42061008 · Publisher ↗
Coral reef ecosystems in the South China Sea (SCS) represent globally significant biodiversity hotspots but are increasingly threatened by environmental change and anthropogenic pressures. In this study, we applied envir...
Coral reef ecosystems in the South China Sea (SCS) represent globally significant biodiversity hotspots but are increasingly threatened by environmental change and anthropogenic pressures. In this study, we applied environmental DNA (eDNA) metabarcoding to assess the diversity and spatial distribution of benthic mollusks by with a focus on the subset of sequences annotated as Mollusca across 19 sampling sites spanning the Xisha, Zhongsha, and Nansha archipelagos. A total of 3338 amplicon sequence variants (ASVs) were quantification of annotation success to Mollusca, of which a fraction could be confidently assigned to 95 molluscan species. ASV richness was highest in the Nansha region, followed by Zhongsha and Xisha, while only six ASVs were shared among all regions, indicating pronounced spatial heterogeneity. Despite high beta diversity among sites (Bray-Curtis dissimilarity: 0.69-1.00), no significant differences in alpha diversity were detected among regions. Among the environmental variables examined, depth emerged as the primary factor influencing community structure. Comparison with traditional morphological surveys demonstrated that eDNA metabarcoding substantially enhances the detection of cryptic and rare taxa. These findings highlight the effectiveness of eDNA-based approaches for marine biodiversity assessment and provide a valuable baseline for conservation and ecosystem management in the SCS.
Effects of micro/nanoplastics on physiological and biochemical responses at different life history stages of Neopyropia yezoensis.
Wang S, Zhao M, Yu M … +6 more , Duan Y, Yang G, Chen G, Wang Z, Wang X, Feng Z
Mar Environ Res · 2026 Jul · PMID 42061007 · Publisher ↗
Micro- and nanoplastics (MNPs) pollution poses significant ecological risks to marine environments and has become a globally recognized environmental concern. As essential primary producers, macroalgae readily adsorb and...
Micro- and nanoplastics (MNPs) pollution poses significant ecological risks to marine environments and has become a globally recognized environmental concern. As essential primary producers, macroalgae readily adsorb and accumulate these particles, potentially disrupting their physiological processes. However, the effects of MNPs on different life history stages of economically important macroalgae remain poorly understood. In this study, we investigated the effects of polystyrene microplastics (PS-MPs, 1 μm) and nanoplastics (PS-NPs, 80 nm) at varying concentrations (0.02-10 mg/L) on the conchospore germination, seedling growth, and physiological biochemical responses of Neopyropia yezoensis. The results showed that 10 mg/L PS-MPs significantly inhibited early conchospore germination and seedling survival rates, whereas 0.1 mg/L PS-MPs promoted conchospore germination. Although PS-NPs had no significant effect on seedling survival, exposure to 10 mg/L PS-NPs significantly inhibited conchospore germination on the first day of exposure. During the thallus stage, PS-MPs exerted no significant effects on the photosynthesis and respiration of thalli but still induced disruption of cellular structural integrity. In contrast, PS-NPs reduced the relative growth rate and net photosynthetic rate, which may be attributed to decreased contents of phycoerythrin (PE) and phycocyanin (PC). Concurrently, both PS-MPs and PS-NPs increased superoxide dismutase (SOD) and catalase (CAT) activities as well as lipid peroxidation level. Integrated Biomarker Response analysis indicated that PS-NPs generally exhibited higher overall toxicity than PS-MPs at the thallus stage. Collectively, these findings demonstrate that the toxicity of MNPs to N. yezoensis depends on particle size, concentration, and life-history stage. This study provides new perspectives for the ecological risk assessment of MNPs.
Occurrence and distribution of waterborne substituted p-phenylenediamine antioxidants and their derivatives in coastal areas of China.
Wu Z, Liu X, Lin T … +3 more , Li J, Liu X, Yao Z
Mar Environ Res · 2026 Jul · PMID 42056787 · Publisher ↗
N,N'-Substituted p-phenylenediamines (PPDs) are rubber antioxidants of emerging concern due to their widespread occurrence in receiving waters via surface runoff. While interest has grown in the acute toxicity of N-(1,3-...
N,N'-Substituted p-phenylenediamines (PPDs) are rubber antioxidants of emerging concern due to their widespread occurrence in receiving waters via surface runoff. While interest has grown in the acute toxicity of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-derived quinone (6PPD-Q) to aquatic organisms, the occurrence and distribution of PPDs and their derivatives in marine environments remain poorly understood. Here, we analyzed PPDs, PPD-quinones (PPD-Qs), and several transformation products (TPs) of 6PPD in seven representative bays and estuaries along the coast of China. Total concentrations of ∑PPDs and ∑PPD-Qs ranged from 0.43 to 13.9 ng/L and from 0.01 to 0.82 ng/L, respectively. Higher ∑PPD and ∑PPD-Q concentrations were observed in the Yangtze River Estuary-Hangzhou Bay and the Pearl River Estuary, influenced by land-based emissions from PPD manufacturing, vehicle-related sources, and local environmental conditions. Correlation and principal component analyses indicated broad consistency in the sources and spatial patterns of PPDs across the studied bays and estuaries. Nonetheless, regional differences in rubber tire-related sources led to varying abundances of individual PPDs among coastal waters. Compared with freshwater environments and relative to their parent PPDs, PPD-Qs were less enriched in coastal waters-likely due to near-source inputs, degradation, and heterogeneous ozonation. Ratios of distinct TP/6PPD pairs highlighted the role of hydrolysis in the persistence and transformation of 6PPD. Notably, median to high ecological risks were associated with 4-hydroxydiphenylamine (a hydrolysis product of 6PPD), N-cyclohexyl-N'-phenyl-1,4-phenylenediamine, and N-1-methylheptyl-N'-phenyl-p-phenylenediamine. These findings underscore the need for broader monitoring of PPD antioxidants and their TPs, beyond just 6PPD and 6PPD-Q.
Effects of polystyrene microplastics on Sargassum fusiforme: concentration- and size-dependent responses.
Liu S, Gao C, Xiang H … +6 more , Jiao J, Zhang X, Wu M, Ma Z, Tong H, Chen B
Mar Environ Res · 2026 Jul · PMID 42056786 · Publisher ↗
Microplastics (MPs) pose a growing threat to global marine ecosystems. Sargassum fusiforme, a commercial brown seaweed, remains understudied with respect to its physiological responses to polystyrene MPs (PS-MPs). This s...
Microplastics (MPs) pose a growing threat to global marine ecosystems. Sargassum fusiforme, a commercial brown seaweed, remains understudied with respect to its physiological responses to polystyrene MPs (PS-MPs). This study investigated the effects of PS-MPs concentrations and particle sizes on key physiological parameters of S. fusiforme. Results demonstrated that, elevated PS-MPs concentrations and reduced particle size significantly inhibited their growth rate, which declined to 2.295% under 100 mg L, 1 μm PS-MPs and to 2.468% under 50 mg L, 1 μm PS-MPs. Concomitantly, photosynthetic performance deteriorated that the maximum electron transport rate, light-use efficiency, and maximal photochemical efficiency all decreased with most markedly in the MPS1 group. In contrast, nitrate uptake and the activities of nitrogen assimilation enzymes including nitrate reductase, glutamine synthetase, and glutamate synthase, were significantly enhanced, with peak activity observed in both MPC100 and MPS1 treatments. Soluble carbohydrate and soluble protein contents increased progressively with PS-MPs stress intensity, reaching maxima of 8.485 mg g and 4.826 mg g, respectively. Moreover, malondialdehyde content and antioxidant enzyme activities, including superoxide dismutase and catalase, rose markedly with increasing PS-MPs concentration and decreasing particle size, indicating escalating oxidative stress. Collectively, these findings indicated that PS-MPs suppress S. fusiforme growth primarily by impairing photosynthetic function and inducing oxidative damage. Concurrently, the alga mounted a compensatory response via accumulation of osmoprotective metabolites and upregulation of nitrogen metabolism. The results of this study provided a fundamental mechanism for ecological risk assessment and offer a reference for sustainable management strategies for seaweed farming in plastic-polluted marine areas.
Coordinated algicidal mechanism of rosenonolactone and fatty acids from Pseudoalteromonas sp. against Karenia mikimotoi.
Xu W, Liu X, Chen Z … +2 more , Guo Y, Shi X
Mar Environ Res · 2026 Jul · PMID 42048715 · Publisher ↗
Algicidal bacteria are critical regulators of harmful algal blooms (HABs), yet the chemical identity and coordinated mechanisms of their active metabolites remain poorly characterized. This study elucidates the algicidal...
Algicidal bacteria are critical regulators of harmful algal blooms (HABs), yet the chemical identity and coordinated mechanisms of their active metabolites remain poorly characterized. This study elucidates the algicidal characteristics of Pseudoalteromonas sp. FDHY-MZ2 against the toxic dinoflagellate Karenia mikimotoi. Using bioassay-guided fractionation coupled with NMR and LC-MS, we identified a novel naturally occurring algicidal complex comprising rosenonolactone and unsaturated fatty acids, rather than a single active compound. This complex exhibited potent algicidal activity, achieving 94.98% removal within 24 h at 12 μg/mL. Mechanistically, we demonstrate a lethal cascade initiated by the disruption of the photosynthetic electron transport chain. The active fraction induced a rapid collapse of the maximal quantum yield (Fv/Fm < 0.1) and relative electron transport rate (rETR), coupled with a failure of non-photochemical quenching (NPQ). This photosynthetic inhibition triggered an uncontrollable burst of reactive oxygen species (ROS) that overwhelmed algal antioxidant defenses (SOD and CAT), leading to severe lipid peroxidation and cell lysis. We propose a coordinated mechanism model where rosenonolactone specifically inhibits photosynthesis, facilitating the membrane-disrupting activity of fatty acids. These findings unravel the chemical basis of the algicidal phenotype in Pseudoalteromonas sp. and highlight the ecological significance of synergistic metabolite strategies in microbial competition and HAB mitigation.
Natural maintenance of biofouling on coral nurseries used across the Great Barrier Reef.
Gillette GM, Camp EF, Edmondson J … +3 more , Booth DJ, Scott RI, Suggett DJ
Mar Environ Res · 2026 Jul · PMID 42048714 · Publisher ↗
In-situ coral nurseries have become widespread across the Great Barrier Reef (GBR) as part of tourism-led stewardship efforts to grow and replant coral at sites of high ecological and socio-economic value. Such coral nur...
In-situ coral nurseries have become widespread across the Great Barrier Reef (GBR) as part of tourism-led stewardship efforts to grow and replant coral at sites of high ecological and socio-economic value. Such coral nursery practices are aimed at reducing costs and increasing propagation efficiency to remain effective at scale. Coral nursery structures are therefore routinely placed in close proximity (1-3 m) to natural reefs with diverse fish assemblages, where fish presence is assumed to reduce biofouling on nursery structures that compete with coral for space. However, the extent to which biofouling occurs has not yet been examined. We therefore assessed the effect of excluding fishes >2.5 cm on sessile community composition of coral nurseries at two GBR sites. Settlement substrates and coral fragments (Acropora species typically used for propagation on the GBR), were placed inside fish cage-exclusion treatments to assess this biofouling on nursery structures at the two reef sites for 112 days. Short-term video surveys were used to identify fish species present on nurseries that would be excluded by the cages. Across sites, mean filamentous turf biomass observed on settlement substrates after 30 days was ∼275-400% greater within cages than within uncaged treatments. At site Rayban, survival of Acropora kenti declined from 83% in controls to 17-33% in fish-exclusion treatments, while A. donei experienced complete mortality in full cages and higher, yet variable survivorship in control and partial-cage treatments (16-33%). In contrast, at site Mojo, A. aff. Abrolhosensis survived irrespective of treatment. Collectively, coral survivorship under enhanced biofouling was therefore species-specific and varied between sites. Fish assemblages on nurseries at both sites were numerically dominated by damselfish (pomacentridae); however, biomass largely comprised of species belonging to Labridae:Scarinae (parrotfishes) and Acanthuridae (surgeonfishes). Bite rate analysis indicated that Scarinae and Acanthuridae interacted most frequently with the nursery frames. We discuss the importance of understanding natural fish assemblage support of localised nursery operations for ensuring effective coral propagation, including use of low-cost experimental approaches we present here for the GBR.
DUST: A framework for quantifying dugong-seagrass interactions using low-cost UAVs.
Mohan M, Selvam PP, Stankovic M … +11 more , Macreadie PI, Gorman D, Karpowicz DA, Hendy I, Watt MS, Ventura D, Broadbent EN, Poursanidis D, Varsha V, Doaemo W, Udagedara S
Mar Environ Res · 2026 Jul · PMID 42048713 · Publisher ↗
Seagrass ecosystems are crucial to global environmental health, food security, and provide ecosystem services such as CO sequestration, environmental buffering and biodiversity maintenance. Dugongs are large marine mamma...
Seagrass ecosystems are crucial to global environmental health, food security, and provide ecosystem services such as CO sequestration, environmental buffering and biodiversity maintenance. Dugongs are large marine mammals primarily found in the Indo-Pacific region that rely on seagrass meadows as their primary food source. Their feeding activity helps maintain seagrass ecosystems. Dugong populations have been declining due to habitat loss, pollution and human activities. Despite their importance, research on dugong-seagrass interactions is limited due to the logistical challenges of traditional field methods and coarser resolution-related difficulties faced with satellite imagery. This study explores the use of low-cost unmanned aerial vehicles (UAVs) to overcome these challenges. UAVs provide high-resolution imagery and data collection in otherwise inaccessible areas, offering a more flexible, cost-effective and accurate method for monitoring seagrass extent and dugong behavior. Although there have been a few UAV-based studies exploring dugong-seagrass interactions in the past, no standard, easy-to-implement work plans are available. We propose a user-friendly, standardized approach - the Dugong UAV Seagrass Tracking (DUST) framework - for studying dugong-seagrass interactions using low-cost UAVs. Our priority is to uphold simplicity and make seagrass-dugong surveys accessible for community-based conservation projects in resource-limited regions. This framework is informed by the insights, applications, gaps and challenges identified through a review of literature and 1:1 meetings with experts in the field. By building on past and ongoing efforts, this straightforward approach aims to inform community-based marine wildlife conservation strategies and deepen our understanding of complex interactions between marine megafauna and vital coastal ecosystems.
Effects of extreme hydrological disturbances on the resilience, resistance, and functional redundancy of fish assemblages in a subtropical estuary.
Belarmino E, Grimm AM, Cabral H … +1 more , Garcia AM
Mar Environ Res · 2026 Jul · PMID 42048712 · Publisher ↗
Hydrological dynamics are fundamental drivers of estuarine ecosystem structure and functioning, directly regulating fish assemblage abundance, species richness and functional redundancy. Using a 24-year monthly time seri...
Hydrological dynamics are fundamental drivers of estuarine ecosystem structure and functioning, directly regulating fish assemblage abundance, species richness and functional redundancy. Using a 24-year monthly time series (1996-2019) combined with performance-based metrics of resistance, resilience and functional redundancy, this study provides evidence of the effects of extreme (>150 m/s) and prolonged (≥5 consecutive months) continental discharge events on fish assemblages in a subtropical estuary of the Southwest Atlantic (32°S, 52°W). Our findings reveal markedly low resistance of shallow-water assemblages to hydrological disturbances, yet highly variable resilience, demonstrating not only immediate ecological disruption but also the capacity for functional reorganization following perturbations. Disturbance intensity and duration exerted differential and lasting impacts on abundance patterns and key ecological functions, leading to both short-term destabilization and persistent structural losses. These alterations have the potential to compromise species recruitment and disrupt critical processes such as larval transport, nursery maintenance and fisheries productivity. The study exposes the heightened vulnerability of estuarine fish assemblages to hydrological stressors intensified by climate change and human pressures, emphasizing the urgent need for proactive management and conservation strategies. Advancing the understanding of ecological resistance, resilience and functional redundancy is crucial to safeguard ecosystem stability and sustain global marine biodiversity.
Distribution characteristics of emerging contaminants and microbial communities in Bohai Sea sediments.
Tian J, Wang L, Wang Y … +2 more , Zheng M, Sun C
Mar Environ Res · 2026 Jul · PMID 42033969 · Publisher ↗
As a semi-enclosed marginal sea in China, the Bohai Sea has long been influenced by substantial pollutant inputs from surrounding rivers, making it an important region for investigating the distribution patterns of pollu...
As a semi-enclosed marginal sea in China, the Bohai Sea has long been influenced by substantial pollutant inputs from surrounding rivers, making it an important region for investigating the distribution patterns of pollutants and microbial communities. In this study, the concentrations of emerging contaminants (ECs) in 19 sediment samples were determined, and metagenomic sequencing was employed to systematically analyze the structure and functional characteristics of microbial communities. The results showed that the detected ECs included synthetic musks (SMs, 7.96-22.85 ng/g dw), dominated by tonalide (AHTN) and galaxolide (HHCB); organophosphate esters (OPEs, not detected-282.27 ng/g dw), were not detected in most samples, but relatively high concentrations were observed at the NS-33 station; and polyhalogenated carbazoles (PHCZs, 0.70-4.36 ng/g dw), with 3,6-dichlorocarbazole (36-CCZ) constituting 61.87% of PHCZs. The microbial community was dominated by Proteobacteria (68.36%). Further network analysis indicated significant correlations between PHCZs and nitrogen metabolism genes, suggesting that PHCZs may inhibit nitrogen fixation and nitrification, while enhancing denitrification. Overall, this study reveals the distribution patterns of ECs and microbial communities in Bohai Sea sediments and their potential associations, providing insights into their interactions in coastal ecosystems.
Influence of suspended particulate matter input on phytoplankton community structure in estuarine environments.
Wang X, Xi Y, Fang K … +7 more , Li C, Li Y, Wang S, Bi R, Chi Z, Tian J, Zeng X
Mar Environ Res · 2026 Jul · PMID 42033968 · Publisher ↗
Riverine suspended particulate matter (SPM) inputs play a crucial role in regulating phytoplankton sedimentation and stability in estuarine ecosystems, thereby mediating organic matter cycling. However, our understanding...
Riverine suspended particulate matter (SPM) inputs play a crucial role in regulating phytoplankton sedimentation and stability in estuarine ecosystems, thereby mediating organic matter cycling. However, our understanding of how the physicochemical properties of SPM influence the short-term response mechanisms of phytoplankton remains insufficient. This study focuses on the sedimentation phase following SPM input and employs a controlled microcosm experimental system. Through short-term sedimentation experiments, it thoroughly investigates the effects of SPM particle size and surface charge on the sedimentation behavior and community composition of marine phytoplankton. The results show that SPM sedimentation substantially decreased phytoplankton biomass in seawater, with sedimentation rates increasing significantly as SPM particle size decreased. Surface charge also strongly enhanced phytoplankton sedimentation. In terms of community composition, SPM markedly altered phytoplankton structure by significantly reducing the relative abundance of Bacillariophyta and Dinophyta while increasing that of Heterokontophyta. Among the examined factors, SPM particle size emerged as a primary driver of these changes. Additionally, SPM inputs increased the relative abundance of microalgae-associated symbiotic bacteria, and combined with the changes in community composition and the results of co-occurrence network analysis, it is hypothesized that the enriched microalgae-associated bacteria may form potential ecological associations with phytoplankton under SPM disturbance conditions. Overall, this study provides new insights into the short-term responses of marine phytoplankton to riverine SPM input during the initial sedimentation phase, and offers preliminary mechanistic references for understanding particulate matter-driven plankton dynamics in estuarine systems.
Spatial and temporal consistency in green algae-induced oyster microbiota dysbiosis and associated increased disease risk.
Dugény E, de Lorgeril J, Petton B … +3 more , Toulza E, Gueguen Y, Pernet F
Mar Environ Res · 2026 Jul · PMID 42026434 · Publisher ↗
Growing interest in microorganisms has extended to the microbiota of hosts and how they interact, as many diseases result from a microbiota imbalance. Recent studies on Pacific oysters Magallana gigas have shown that ind...
Growing interest in microorganisms has extended to the microbiota of hosts and how they interact, as many diseases result from a microbiota imbalance. Recent studies on Pacific oysters Magallana gigas have shown that individuals exposed to particular communities, like green algae holobionts from the genus Ulva, were more susceptible to the infection by the Ostreid herpesvirus type 1 (OsHV-1), coinciding with dysbiosis of the bacterial microbiota and modification of host immune response. Considering that the microbiota of macroalgae and oysters vary with time and geographical location, dysbiosis induced by green algae on oysters may not be systematic and could depend on the origin of the green macroalgal assemblage. We therefore conducted an experiment with macroalgae and oysters from several origins to examine whether the biotic interactions previously observed can be extended more generally and attest to a negative effect of all green algae on several oyster families. Two multiparental lines of oysters with different disease resistance were acclimated with four sources of green algae from different sites in Brittany (France). Then, oysters were challenged with OsHV-1 and we followed host mortality and virus replication dynamics in seawater, while investigating the response of the oyster microbial community. Overall, the results confirm that green algae increase the risk of mortality, irrespective of their geographical origins and oyster line. This coincided with early dysbiosis of the oyster bacterial microbiota. The only exception concerned oysters exposed to green algae from the English Channel which presented mortalities similar to the control, although with a change in microbiota composition and structure, but less pronounced than in other exposures with stronger dysbiosis and levels of mortality.
Multi-omics investigation of the molecular response of typical bloom-forming species Prorocentrum shikokuense to stoichiometric phosphorus limitation under a high nitrogen-to-phosphorus ratio.
Shen A, Shen W, Zhu Y … +1 more , Zeng J
Mar Environ Res · 2026 Jun · PMID 42025279 · Publisher ↗
Nitrogen and phosphorus are essential nutrients for marine phytoplankton, with their ratio critically influencing ecosystem dynamics. The high nitrogen-to-phosphorus (N/P) ratio in the East China Sea (ECS) results in sto...
Nitrogen and phosphorus are essential nutrients for marine phytoplankton, with their ratio critically influencing ecosystem dynamics. The high nitrogen-to-phosphorus (N/P) ratio in the East China Sea (ECS) results in stoichiometric phosphorus limitation, which is a primary constraint on phytoplankton growth. Nevertheless, the dinoflagellate Prorocentrum shikokuense can form persistent, large-scale blooms even when dissolved inorganic phosphorus concentrations are low. The molecular mechanisms behind its adaptation to stoichiometric P limitation under high N/P ratios remain unclear. This study applied multi-omics analyses to investigate the response of P. shikokuense to stoichiometric P limitation under a high N/P ratio. We identified 431 differentially expressed genes (DEGs: 139 up, 292 down), 617 differentially expressed proteins (DEPs: 135 up, 482 down), and 217 differentially accumulated metabolites (DAMs: 51 up, 166 down). Integrated analysis revealed 61 metabolic pathways common to at least two omics layers. Key enriched pathways included photosynthesis, oxidative phosphorylation, nucleotide metabolism, and nitrogen metabolism. Pathways related to genetic information processing were downregulated, and energy metabolism was constrained. This subsequently suppressed nitrogen transport, assimilation, allocation, and secondary metabolism. In summary, these results elucidates the transcriptional, proteomic, and metabolic adjustments enabling P. shikokuense to thrive under stoichiometric P limitation based on a high N/P ratio. These findings provide a scientific basis for understanding its bloom dynamics in the ECS waters subject to stoichiometric P limitation under high N/P ratios.
Vegetation preference and the puzzle of abandonment: high-quality spawning habitat remains unused by Pacific herring (Clupea pallasii).
Dingwall JT, Qualley J, Thompson M … +2 more , Long S, Bates AE
Mar Environ Res · 2026 Jun · PMID 42019095 · Publisher ↗
Understanding factors that drive the spawning behaviour of migratory fish populations is essential for effective and sustainable fisheries management. Pacific herring (Clupea pallasii) in the Strait of Georgia, British C...
Understanding factors that drive the spawning behaviour of migratory fish populations is essential for effective and sustainable fisheries management. Pacific herring (Clupea pallasii) in the Strait of Georgia, British Columbia, Canada, have undergone a significant contraction in spawning range over the last century, abandoning numerous historical spawning sites in favour of a single dominant region. The mechanisms underpinning the reoccupation of these abandoned regions remain unclear. This study evaluated if habitat type limits reoccupation by quantifying spawning substrate availability at both active and abandoned sites and assessing spawning vegetation preferences. We developed a predictive model of egg deposition based on 36 years of dive surveys (1988-2024) and applied it to vegetation data collected via remotely operated vehicle surveys at eight sites. We found that herring prefer structurally complex vegetation, particularly the invasive macroalga (Sargassum muticum), which supports significantly higher predicted egg densities than native flat kelps or seagrasses. However, contrary to the habitat limitation hypothesis, abandoned sites frequently possess vegetation assemblages equal to or exceeding the quality and density of those at active spawning grounds. Substrate availability is thus not a primary bottleneck for spawning recovery at abandoned sites. Other factors may play a role, such as learned migratory behavior and the loss of diverse spawning contingents. Consequently, while vegetation restoration can benefit ecosystem functioning, the rapid recolonization of historical spawning grounds is unlikely without management interventions targeting population-level constraints rather than habitat enhancement alone.
Meiofaunal colonization potential in barren grounds: new cues for habitat rehabilitation.
Bianchelli S, Buschi E, Tamburello L
Mar Environ Res · 2026 Jun · PMID 42013676 · Publisher ↗
Anthropogenic pressures have a prominent role in fostering regime shifts, which, in turn, induce negative consequences like habitat and biodiversity loss. In the Mediterranean Sea, hard-bottom ecosystems dominated by mac...
Anthropogenic pressures have a prominent role in fostering regime shifts, which, in turn, induce negative consequences like habitat and biodiversity loss. In the Mediterranean Sea, hard-bottom ecosystems dominated by macroalgal forests formed by Cystoseira sensu lato may switch to less-productive barren grounds. Ecological restoration is increasingly acknowledged as the most effective strategy to reverse the biodiversity loss, together with conservation, fostered by resilience of marine ecosystems once the pressures are mitigated. Meiofauna have been studied both for assessing the loss of biodiversity and ecosystem functioning in barren grounds and the success of restoration intervention of Cystoseira s.l. forests. Here, we tested the possibility for meiofauna to colonize barren grounds, once they have a suitable habitat, simulating a possible habitat rehabilitation intervention (i.e., the presence of a substrate to settle, mimicking the three-dimensional structure of Cystoseira s.l. as substrate for associated biodiversity). We used artificial substrates to assess the potential capability of meiofauna to colonize macroalgal forests and barren grounds, comparing meiofaunal assemblages in the artificial substrates with those retrieved from benthos, in both habitats. Significant higher abundance, richness of higher taxa and different taxonomic composition were observed in macroalgal forests than barren grounds. Moreover, high abundance and richness of taxa were observed in artificial substrates in barren grounds. This suggests that meiofaunal diversity can be recovered once the habitat is rehabilitated, also in degraded barren grounds. Complementary actions, as reintroducing the habitat-forming species in combination with artificial substrates for benthic components, can augment the restoration success and shorten ecosystem recovery.
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