Marine Environmental Research[JOURNAL]
Sun
200 papers
Blue and green: A portrait of two portunoidea crabs from away and their interactive effects on catch.
Marchessaux G, Crane LC, Gutzler BC … +3 more , Smith SA, Sarà G, Goldstein JS
Mar Environ Res · 2026 May · PMID 42218865 · Publisher ↗
Biological invasions and climate-driven range expansions are generating novel assemblages of interacting species with ecological and socio-economic consequences. While competition between invasive and native species has...
Biological invasions and climate-driven range expansions are generating novel assemblages of interacting species with ecological and socio-economic consequences. While competition between invasive and native species has been widely documented, interactions between invasive and range-expanding species remain comparatively underexplored, despite their growing relevance. This study set out to compare a "reciprocal invasion" of two Portunoidea crabs-American blue crab (Callinectes sapidus) and the European green crab complex (Carcinus spp.)-between the Mediterranean Sea (Italy), where the green crab is native and the blue crab a recent invader, and the Gulf of Maine (USA), where the green crab is an established invader and the blue crab is expanding its range. Through a series of trapping surveys, we found a consistent negative relationship in catches between these two species across regions, suggesting that C. sapidus is a competitive dominant regardless of geographic context. Further, we observed different responses to temperature and salinity between species, suggesting that their coexistence is likely limited by both competitive exclusion and environmental factors. Across both regions, blue crab catches peaked during warm seasons and higher temperature-salinity conditions, whereas green crabs dominated cooler periods and lower salinities, revealing consistent seasonal and environmental niche segregation that reinforces competitive exclusion patterns. This study highlights the importance of considering both environmental niches and biotic interactions as they jointly shape invasion outcomes, and demonstrates the utility of cross-region comparisons for better understanding the conservation implications of novel species interactions in an ever-changing ecosystem.
Kelp forests as natural barriers against invasive turf-forming algae.
Alvite N, Barrientos S, Barreiro R … +1 more , Piñeiro-Corbeira C
Mar Environ Res · 2026 May · PMID 42217338 · Publisher ↗
Kelps are key foundation species on temperate and Artic rocky shores, forming structurally complex habitats that are increasingly being lost and replaced by turf-forming algae. This study aimed to document the transition...
Kelps are key foundation species on temperate and Artic rocky shores, forming structurally complex habitats that are increasingly being lost and replaced by turf-forming algae. This study aimed to document the transition from Laminaria ochroleuca forests to the proliferation of the invasive turf-forming red algae Falkenbergia rufolanosa, the tetrasporophyte stadium of Asparagopsis armata, in NW Spain. Seasonal surveys (winter, spring and autumn) were conducted over a five-year period across eight rocky reefs to analyze the abundance of kelps and the cover of the invasive species. Our results indicate that the cover of the Falkenbergia stadium was significantly lower in healthy reefs than in degraded ones. Additionally, we observed a general decline in the number of adult Laminaria ochroleuca individuals across both healthy and degraded reef. The results of our study support the idea that healthy kelp forests could act as barriers to invasive turf species, while degraded forests may facilitate their spread. This resistance to invasion underscores the ecological importance of kelp forests and highlights the need for conservation and restoration strategies.
Long term salinity acclimation buffers combined impacts of heat-salinity on Daphnia by reconfiguring osmoregulatory transcription.
Huang J, Chen Y, Jin Z … +2 more , Wu R, Yang Z
Mar Environ Res · 2026 May · PMID 42217337 · Publisher ↗
Gradual salinization increasingly co-occurs with episodic heat stress, yet how these temporally asynchronous stressors jointly shape biotic responses remains unclear. Here, we tested whether prior salinity acclimation al...
Gradual salinization increasingly co-occurs with episodic heat stress, yet how these temporally asynchronous stressors jointly shape biotic responses remains unclear. Here, we tested whether prior salinity acclimation alters temperature and salinity interactions on Daphnia magna by comparing acclimated and non-acclimated individuals across five salinities (0, 0.06, 0.08, 0.10, 0.12 M) and three temperatures (20, 25, and 30 °C). In non-acclimated D. magna, warming and salinity synergistically impaired performance, reducing EC for offspring of the first brood and number of broods, and elevating integrated biomarker response (IBR) values under salinity stress. In contrast, salinity acclimation transformed this interaction into antagonism, with heat stress no longer exacerbating salinity induced damage or elevating IBR values. Salinity acclimation enhanced heat tolerance mainly at 0.08 M, where the change rate in the heat tolerance for reproductive traits, survival time, time to maturity, and spine length at maturity improved under warming (P < 0.001). Transcriptional and trait-gene correlations indicated a shift from an injury-linked, highly inducible state to a buffered state. In non-acclimated D. magna, combined stress synergistically upregulated osmoregulatory (Na/K-ATPase α/β), protein homeostasis (HSP70), and antioxidant (Cu/Zn SOD, CAT) genes. After acclimation, salinity still increased Na/K-ATPase α/β expression, but warming no longer amplified this response and instead dampened salinity-induced oxidative stress defenses. Gene expression was broadly negatively correlated with phenotype, but these correlations weakened after acclimation, supporting partial decoupling. Overall, salinity acclimation converts synergistic heat-salinity effects into antagonistic outcomes, highlighting the importance of exposure history and stressor timing for multiple-stressor risk assessment.
From carbonate chemistry to community responses: Thematic evolution in ocean acidification and microbial research- a bibliometric analysis.
Sun Y, Liu Y, Su Q … +3 more , Li C, Zhao S, Zhou J
Mar Environ Res · 2026 May · PMID 42214871 · Publisher ↗
Ocean acidification (OA) is reshaping marine biogeochemistry and threatens microbial communities that regulate carbon and nutrient cycling. Although existing bibliometric reviews have examined OA in relation to coral ree...
Ocean acidification (OA) is reshaping marine biogeochemistry and threatens microbial communities that regulate carbon and nutrient cycling. Although existing bibliometric reviews have examined OA in relation to coral reefs, calcifying organisms, and broader marine ecosystems, no study has systematically mapped the specific sub-domain of OA impacts on microbial ecology, a gap that hinders identification of methodological blind spots, collaboration imbalances, and under-explored research frontiers unique to microbial systems. Meanwhile, research progress on OA-driven microbial change remains fragmented and lacks a systematic analysis of the field's evolutionary trajectory and emerging frontiers. This study presents a comprehensive bibliometric analysis of 495 publications retrieved from the Web of Science Core Collection (2005-2025), utilizing CiteSpace to map the knowledge domain of OA impacts on microbial ecology. Temporal analysis reveals three distinct developmental phases: emergence (2005-2010), exponential growth (2011-2021), and recent stabilization (2022-2025). The global collaboration network spans 53 countries, characterized by a triadic leadership structure involving China, the United States, and Germany, with the GEOMAR Helmholtz Centre serving as a central institutional hub. Keyword co-occurrence and burst detection analyses uncover a significant paradigm shift: the research focus has transitioned from foundational carbonate chemistry parameters to complex ecosystem-relevant microbial processes, including community structure, functional genes, and biogeochemical cycling. Notably, "responses" emerges as the most active contemporary research frontier with the strongest recent citation burst, reflecting a consolidated focus on how microbial communities adapt to acidification stress at physiological, community-structural, and functional levels. However, network analysis also reveals structural blind spots: archaea and viral ecology remain conspicuously absent from high-frequency keyword clusters despite their recognized ecological importance, and research contributions from Africa, Southeast Asia, and Small Island Developing States are markedly limited. Based on these findings, we propose four evidence-linked strategic directions centered on multi-omics integration, spatiotemporal expansion through global observatory networks, factorial multi-stressor experimental designs, and bridging molecular processes to ecosystem-scale biogeochemical cycles. This study provides a data-driven roadmap for next-generation research on OA-microbe interactions, essential for predicting ecosystem resilience in a changing ocean.
Biophysical modeling of Posidonia oceanica fruit dispersal in the Mediterranean Sea.
Barrier C, Durieux ÉDH, Pasqualini V … +2 more , Astruch P, Monnier B
Mar Environ Res · 2026 May · PMID 42208192 · Publisher ↗
Understanding the dispersal dynamics of Posidonia oceanica fruits is essential to assess the resilience and connectivity of Mediterranean seagrass ecosystems. Given the species' clonal growth, floating fruit dispersion r...
Understanding the dispersal dynamics of Posidonia oceanica fruits is essential to assess the resilience and connectivity of Mediterranean seagrass ecosystems. Given the species' clonal growth, floating fruit dispersion represents the critical vector for long-range genetic diversification and population expansion. To characterize these dynamics, a biophysical modeling framework was applied across the Mediterranean Sea, coupling the Ichthyop Lagrangian tracker to high-resolution hydrodynamic fields from the NEMO-based Mediterranean Sea Physics Reanalysis (1/24° resolution). Fruit releases were simulated from 483 mapped meadow polygons over four years (2021-2024) under three buoyancy scenarios (14, 21, and 28 days) to capture biological variability. Results demonstrate that floating duration strongly controls the spatial footprint of dispersal. While short buoyancy (14 days) favors retention within localized hotspots, such as the Gulf of Gabès and the Aegean Sea, extended durations (21-28 days) activate long-distance corridors connecting North African sources to Central and Eastern basins. Network analysis reveals functional heterogeneity among meadows: while most act as localized exporters, a distinct subset emerges as "hub" sources with high export strength and broad sink diversity. Cross-scenario consistency maps identify robust coastal sinks where propagules accumulate regardless of buoyancy duration. Our results demonstrate that Mediterranean connectivity is partitioned between high local retention and strategic long-distance corridors, a structure determined by the interaction of regional currents and fruit floating potential. This study provides a scientific basis for Mediterranean conservation by identifying specific high-value hub meadows that sustain basin-scale gene flow and persistent sink zones where restoration efforts should be prioritized.
Viability-based assessment of antibiotic resistance in Vibrio scophthalmi using propidium monoazide-qPCR.
Son HS, Yun KW, Seong MJ … +2 more , Lee SM, Kim MC
Mar Environ Res · 2026 May · PMID 42208191 · Publisher ↗
Vibrio scophthalmi is a marine fish pathogen commonly isolated from Paralichthys olivaceus and Scophthalmus maximus, two flatfish species primarily farmed in East Asia. Conventional antibiotic susceptibility testing (AST...
Vibrio scophthalmi is a marine fish pathogen commonly isolated from Paralichthys olivaceus and Scophthalmus maximus, two flatfish species primarily farmed in East Asia. Conventional antibiotic susceptibility testing (AST) and minimum inhibitory concentration (MIC) assays detect only culturable cells and may therefore underestimate bacterial survival under antibiotic stress, whereas quantitative PCR (qPCR) can overestimate bacterial abundance by amplifying DNA from nonviable cells. To address these methodological limitations, propidium monoazide (PMA)-qPCR was applied as a viability-based molecular approach to quantify membrane-intact V. scophthalmi cells in isolates obtained from wild marine fish. Six antibiotics were evaluated, and the results of AST, MIC, and PMA-qPCR were comparatively analyzed using paired t-tests and Bland-Altman analyses. PMA-qPCR consistently reduced amplification from membrane-compromised cells and yielded more conservative estimates of bacterial abundance than conventional qPCR. Among the tested antibiotics, tetracycline treatments showed limited reductions in PMA-qPCR signals despite growth suppression in MIC assays, indicating the persistence of membrane-intact cells under bacteriostatic conditions. These findings are consistent with previous reports describing tetracycline tolerance in V. scophthalmi. This study represents the first application of PMA-qPCR for antibiotic susceptibility assessment in V. scophthalmi within a viability-based framework. The results highlight the methodological potential of this approach to complement culture-based assays and support future studies of antibiotic-resistant bacteria in marine and aquaculture contexts within a One Health-oriented perspective.
Impact of submarine groundwater discharge on meiofaunal nematode community structure along the southwest coast of India.
Vishnudattan N, Jayachandran PR, Nandan SB … +2 more , Aravind EH, Suresh Babu DS
Mar Environ Res · 2026 May · PMID 42202598 · Publisher ↗
Submarine groundwater discharge (SGD) is a vital yet understudied driver of ecological change in coastal ecosystems, particularly in relation to sediment dwelling meiofaunal communities. This study investigates the impac...
Submarine groundwater discharge (SGD) is a vital yet understudied driver of ecological change in coastal ecosystems, particularly in relation to sediment dwelling meiofaunal communities. This study investigates the impact of SGD on the richness, density, biomass, structural and functional diversity of free-living meiofaunal nematodes along the southwest coast of India. Field sampling was conducted across fifteen locations, including 11 SGD impacted and 4 unimpacted sites during three seasonal cycles for two years. Results showed significantly reduced nematode taxa richness, density, and biomass at SGD impacted sites compared to unimpacted sites, highlighting remarkable difference in community structure. The Co-occurrence network analysis revealed fragmented species interactions in SGD sites, in contrast to the denser and more stable networks at unimpacted sites. RLQ analysis demonstrated that SGD significantly structures nematode communities through environmental gradients, particularly salinity, dissolved oxygen, and grain size, shaping distinct trait associations. Finally, these findings underscore the importance of nematodes as sensitive ecological indicators and highlight the structuring role of SGD on coastal benthos.
Organic matter, microplastics and macrofaunal communities associated with Posidonia oceanica meadows.
Martinez M, Minetti R, La Marca EC … +6 more , Montalto V, Rinaldi A, Costa E, Garaventa F, Mirto S, Ape F
Mar Environ Res · 2026 May · PMID 42202597 · Publisher ↗
Coastal ecosystems are increasingly affected by anthropogenic pressures such as organic enrichment and microplastic contamination, which threaten benthic habitats and biodiversity. Seagrass meadows, such as those formed...
Coastal ecosystems are increasingly affected by anthropogenic pressures such as organic enrichment and microplastic contamination, which threaten benthic habitats and biodiversity. Seagrass meadows, such as those formed by Posidonia oceanica, are particularly vulnerable in urbanized areas, making it essential to understand the combined effects of multiple stressors on their functioning and associated communities. Here we study the benthic macrofaunal community structure at two coastal sites characterised by the presence of Posidonia oceanica meadows affected by microplastic contamination and organic enrichment. The results showed that faunal abundance and taxa richness were lower in sediments characterised by higher organic matter and MPs amount, and lower P. oceanica density, coinciding with the area subjected to higher urbanisation, as revealed by the biopolymeric carbon and total phyto-pigments analysis. Therefore, these results suggest that the high input of organic matter of human origin can represent a stressor for P. oceanica meadows, leading to a reduction in shoot density. This condition, associated with a greater accumulation of microplastics in the underlying sediments, appeared to have negative effects on the associated biodiversity. Our findings contribute to advancing current knowledge on the effect of multiple stressors (i.e. the organic enrichment and the MPs contamination) on marine ecosystems and on the species diversity they support, and highlight the urgent need to implement the investigations on potential cumulative effects among pollutants and actions mitigating pressures on key coastal habitats such as seagrass meadows.
Current and future thermal habitat suitability of the European clam Ruditapes decussatus (Linnaeus, 1758) in Mediterranean coastal lagoons.
Palmas F, Gentili A, Cabiddu S … +6 more , Pasquini V, Addis P, Sarà G, Bosch-Belmar M, Tantillo MF, Pusceddu A
Mar Environ Res · 2026 May · PMID 42202596 · Publisher ↗
The European clam Ruditapes decussatus contributes to ecosystem functioning and supports fisheries in coastal lagoons across the North-Eastern Atlantic and Mediterranean. Although the ecological consequences of climate-d...
The European clam Ruditapes decussatus contributes to ecosystem functioning and supports fisheries in coastal lagoons across the North-Eastern Atlantic and Mediterranean. Although the ecological consequences of climate-driven warming in lagoon systems are increasingly documented, its implications for the spatial distribution and habitat suitability of benthic species remain poorly understood. To address this gap, we quantified the metabolic response of R. decussatus across a wide range of temperatures (8-38 °C) by measuring respiration rate (RR). RR increased with temperature, from low values at 8 °C (0.07 ± 0.04 mg O h g DW) to a maximum around 26 °C (1.55 ± 0.40 mg O h g DW), followed by a sharp decline at higher temperatures. Among 24 candidate Thermal Performance Curve (TPC) models, the best-fitting function indicated an optimal temperature of 26.7 °C and a critical thermal maximum of 38.0 °C. TPC-derived parameters were then used to generate seasonal maps of Thermal Habitat Suitability (THS) under reference conditions (2017-2022) and future climate warming scenarios (RCP 4.5 and RCP 8.5 for 2050) across four Mediterranean lagoons. Under reference conditions, THS showed seasonal and spatial variability, with highest suitability during summer and early autumn and lower values in winter. Future projections indicate a seasonal reshaping of habitat suitability, with increased values during winter, spring, and autumn, and a moderate decline during summer (up to 4% under RCP 8.5). Climate warming may therefore reshape the reproduction timing of the species, with implications for population dynamics and ecosystem functioning. Integrating THS into management frameworks may support future aquaculture and conservation planning.
Neglected impacts and modeling uncertainties of seismic surveys on fish and fisheries: Knowledge gaps and research needs.
Reis-Filho JA, Tomás ARG, Neto DG … +1 more , Noleto-Filho E
Mar Environ Res · 2026 May · PMID 42202595 · Publisher ↗
Offshore oil and gas exploration has long driven global economic growth, and marine seismic surveys (MSS) constitute the initial phase of these operations. Although much of the impact literature focuses on marine mammals...
Offshore oil and gas exploration has long driven global economic growth, and marine seismic surveys (MSS) constitute the initial phase of these operations. Although much of the impact literature focuses on marine mammals and, to a lesser extent, sea turtles and birds, empirical understanding of how MSS may affect fish and fisheries remains limited, particularly in the South Atlantic, where large-scale assessments are virtually absent. Here, we address this gap using a two-decade spatiotemporal dataset encompassing approximately 800,000 km of MSS along the Brazilian coast. We integrated seismic effort metrics with fishery catch data from the Sea Around Us database to derive a Seismic Sensitivity Index (SSI) representing the relative sensitivity of key exploited groups, including tunas, billfishes, sharks, and rays, across all Brazilian sedimentary basins. We implemented multiple SSI frameworks combining seismic pressure indicators (e.g., Sound Exposure Level, licensed survey area, ramp-up zones), catches-weighted fishery importance, environmental stochasticity, and estimates of fish-seismic overlap probability. These complementary approaches revealed marked spatial contrasts in relative sensitivity and potential exposure. Southern basins, where seismic activity has been most frequent and intense, consistently showed higher SSI values for tunas and billfishes, whereas sharks and rays exhibited elevated SSI values in northern basins. Given the scarcity of comprehensive empirical studies in the South Atlantic and the extensive footprint of seismic operations across Brazil's continental shelf, our results provide the first large-scale, data-driven screening of potential sensitivity to MSS among ecologically and economically important fish groups. This framework offers a foundation for prioritizing future empirical research, guiding risk assessments, and informing the spatial management of seismic activities.
Global-scale quantification of mesopelagic fish-mediated carbon fluxes.
Liu Q, Chen Z, Zhang L … +3 more , Saba GK, Zhou L, Huang H
Mar Environ Res · 2026 May · PMID 42190556 · Publisher ↗
Mesopelagic fish represent the largest vertebrate biomass on Earth, yet quantifying their role in marine carbon fluxes and the marine environment remains a challenge. Here, we present a mechanistic model integrating body...
Mesopelagic fish represent the largest vertebrate biomass on Earth, yet quantifying their role in marine carbon fluxes and the marine environment remains a challenge. Here, we present a mechanistic model integrating body size- and temperature-dependent daily carbon release processes to estimate dissolved organic carbon (DOC), carbon dioxide (CO), and particulate carbon (PC) released by mesopelagic fish across the global open ocean. Carbon budgets were modeled separately for diel vertically migratory (DVM) and non-vertically migratory (NM) mesopelagic fish in tropical/subtropical (40°N-40°S) and high-latitude (40°-70°N/S) zones. Our results indicate that mesopelagic fish release 0.64-8.29, 0.48-6.17, and 0.18-2.30 Pg C/yr of DOC, CO, and PC, respectively, with a net production of 0.16-2.20 Pg C/yr. DVM fish mediate an active carbon export of 0.23-3.85 Pg C/yr through vertical migration, which is comparable to the active carbon fluxes mediated by mesozooplankton. Our results also show that the gross growth efficiency (i.e., net production divided by ingested food carbon, 12%) of DVM mesopelagic fish is, on average 21% higher than that of NM mesopelagic fish on a global scale, which provides a new explanation for the advantages of diel vertical migration. These findings provide the first global estimates of mesopelagic fish-driven DOC, CO, and PC fluxes, highlighting their important role in the ocean carbon cycle, biological carbon pump, and marine environment.
Designing with dispersal: Connectivity-informed site selection for bivalve recruitment.
Grieco G, Larsen J, Schourup-Kristensen V … +5 more , Clubley CH, Ishimwe AP, Knudsen MA, Dolmer P, Maar M
Mar Environ Res · 2026 May · PMID 42190555 · Publisher ↗
Bivalve beds play an important role in coastal ecosystems and understanding factors that influence their persistence and recruitment is critical, especially given the strong impact of human activities on these habitats....
Bivalve beds play an important role in coastal ecosystems and understanding factors that influence their persistence and recruitment is critical, especially given the strong impact of human activities on these habitats. Consequently, marine mussel bed restoration projects have gained momentum in recent years. However, bivalve bed restoration success critically depends on well-planned site selection that optimises larval connectivity to ensure recruitment and long-term population viability. Here, we present a comprehensive connectivity analysis to determine recruitment and potential restoration of blue mussel (Mytilus edulis) reefs, exemplified for Roskilde Fjord, Denmark. A biophysical model was used to predict larval dispersal. Hotspots for potential new blue mussel reefs were first identified based on habitat suitability and environmental conditions and then overlapped with site selection guidelines. Graph theory metrics were used to characterise the connectivity patterns in the basin. This analysis showed that carefully planned reef placement can improve survival of the mussel population by achieving more homogeneous connectivity and increasing inter-site connections. Modelling of the external larval supply demonstrated minimal recolonisation potential from outside the system, highlighting the importance of internal connectivity for recruitment. While nutrient loads remain a key pressure affecting mussel health in this system and reducing them is a major concern, our results provide quantitative evidence-based guidance for optimising bivalve recruitment. Moreover, integrating biophysical modelling with network analysis provides an improved framework for identifying sites with a higher chance of establishing new bivalve reefs through enhanced larval connectivity, with broader applications for potential marine restoration efforts in semi-enclosed coastal systems worldwide.
Tidal pumping modulates the dissolved organic carbon dynamics and exchange fluxes across the mangrove-fringed estuary-coast interface in Zhanjiang Bay, China.
Zhang P, Lei J, Zhou L … +5 more , Chen X, Yu H, Ye Q, Huang K, Zhang J
Mar Environ Res · 2026 May · PMID 42190554 · Publisher ↗
Estuaries, as key interfaces between land and sea, play an important role in coastal carbon cycling. This study investigates how tidal pumping influences dissolved organic carbon (DOC) dynamics at the estuary-coastal int...
Estuaries, as key interfaces between land and sea, play an important role in coastal carbon cycling. This study investigates how tidal pumping influences dissolved organic carbon (DOC) dynamics at the estuary-coastal interface of Zhanjiang Bay (ZJB). DOC concentrations were higher in the dry season than in the wet season, with mean values of 3.34 ± 1.10 mg Land 2.82 ± 0.83 mg L, respectively, and similar patterns were observed at the estuarine mixing zone (Site E2:3.68 mg L and 2.58 mg L, respectively). It indicated enhanced retention and tidal remobilization of terrestrially influenced organic matter under low river discharge. Optical signatures revealed tidal-phase mediated DOM transformation: ebb tides export more aromatic, terrestrial-like DOM (SUVA = 10.28 ± 4.42 L mg m), while fluorescence components shift from terrestrial humic-like material upstream to microbial/protein-like material seaward. Net DOC flux across the monitored estuarine section showed persistent seaward transport, averaging approximately 0.14 ± 0.01 t h in the dry season and 0.27 ± 0.02 t h in the wet season. Overall, DOC dynamics in the ZJB estuary were influenced by terrestrial inputs and were closely coupled with tidal exchange and biogeochemical processes, providing insights into carbon cycling in mangrove-fringed estuarine systems.
Formation and detection of marine algal toxins and their distribution in Chinese coastal waters.
Cheng F, Zhang J, Li Q … +4 more , Hu B, Yu HB, Li S, Zhang X
Mar Environ Res · 2026 May · PMID 42190553 · Publisher ↗
Marine algal toxins, a diverse group of bioactive secondary metabolites produced by harmful algal species, pose significant threats to human health, marine ecosystems, and aquaculture economies. Driven by human activitie...
Marine algal toxins, a diverse group of bioactive secondary metabolites produced by harmful algal species, pose significant threats to human health, marine ecosystems, and aquaculture economies. Driven by human activities and climate change, the increasing frequency and scale of harmful algal blooms have expanded the contamination scope of these toxins. This trend underscores an urgent need to better understand their formation and distribution, and to develop more effective methods for their detection and monitoring. This review summarizes recent advances in the formation, detection and monitoring of marine algal toxins, with special emphasis on cases of toxin distribution and pollution in Chinese coastal waters. Notably, advances in genomics and enzymology have begun to decipher the formation mechanism of these toxins, thus laying a fundamental basis for toxin research and risk management. Furthermore, the rapid development of detection technologies and the continuous strengthening of monitoring efforts enable us to track the formation and distribution of toxins in a more timely and accurate manner. Beyond their adverse effects, the unique bioactivities and mechanisms of action of marine algal toxins offer valuable molecular candidates for drug development or scientific research, underscoring the dual role of these natural products. Future research should prioritize the development of rapid, portable detection tools, elucidation of unresolved biosynthetic mechanisms, and exploration of safe therapeutic applications to better mitigate risks and explore the potential of these marine-derived compounds.
Flood events from climate extremes drastically shift prey energy densities.
Nitschke J, Ye Q, Baring R … +1 more , Dittmann S
Mar Environ Res · 2026 May · PMID 42184792 · Publisher ↗
The variability and intensity of climate events is increasing with global warming. Estuaries are subject to more frequent and severe droughts and floods, which impact biota directly and through environmental changes. Imp...
The variability and intensity of climate events is increasing with global warming. Estuaries are subject to more frequent and severe droughts and floods, which impact biota directly and through environmental changes. Impacts on prey propagate through food webs by affecting energy availability for higher trophic-level predators. This study investigated changes in energy density of macroinvertebrates and small-bodied fish in the estuary of Australia's largest river system, before and after the largest flood in 70 years, to test impacts on prey for birds and fish in this Ramsar listed wetland. The flood led to a pronounced shift in prey energy density and changes in several environmental conditions, including in the hypersaline southern parts of the ecosystem, where salinities substantially declined, allowing prey to colonise this region. The spatiotemporal trends in macroinvertebrate energy density were more distinct than for fish and largely followed salinity gradients. The area of greatest prey energy density shifted from near the river mouth before the flood to approximately 50 km into the coastal lagoon after the flood. Around 10 months after the flood peak, after an initial decline, macroinvertebrate energy density had increased again in the northern estuary region and remained elevated in the south, thereby expanding the area with moderate energy resources. The effects of this flood demonstrate that higher flows could help enhance energy provisioning for predators by reducing hypersaline conditions. Overall, this study improves our understanding of the effects of extreme climate events on prey dynamics and trophic functioning in estuarine food webs.
Foraging ecology of the critically endangered hawksbill sea turtle in the Gulf of Guinea.
Vieira S, Ferreira-Airaud B, Baptista V … +3 more , Tiwari M, Castilho R, Teodósio MA
Mar Environ Res · 2026 May · PMID 42184791 · Publisher ↗
Understanding the ecological roles of critically endangered species is essential for effective conservation planning. This study investigates the foraging ecology and nutritional condition of the hawksbill sea turtle (Er...
Understanding the ecological roles of critically endangered species is essential for effective conservation planning. This study investigates the foraging ecology and nutritional condition of the hawksbill sea turtle (Eretmochelys imbricata) in São Tomé Island, a key foraging ground in the Gulf of Guinea. We integrated stable isotope analyses of epidermal tissues with RNA/DNA ratios to assess habitat use, trophic position, and physiological status across life stages. Thirty hawksbill turtles (juveniles and adults) were sampled during in-water surveys conducted between 2021 and 2022 using minimally invasive techniques. Prey samples were also collected for isotopic baselines. Carbon (δC) and nitrogen (δN) values revealed significant ontogenetic shifts, with adults occupying broader isotopic niches. While sponges remained the dominant food source at both stages, adults exhibited greater dietary diversity, including red algae and tunicates. Juveniles showed higher spatial and temporal fidelity, suggesting stronger residency patterns. Estimated trophic positions ranged from 2.57 to 2.79, consistent with secondary consumers. RNA/DNA ratios indicated higher metabolic activity in juveniles and males, while lower values in females likely reflect reproductive metabolic suppression. These findings represent the first integrative assessment of hawksbill turtle foraging and nutritional condition in the region. The study provides critical baseline data on one of the most genetically isolated and endangered hawksbill populations worldwide. This approach enhances understanding of their ecological function and supports the development of targeted conservation actions that account for life-stage-specific needs, contributing to adaptive management and long-term recovery of this critically endangered population.
Proteomic insights into the combined effects of near-threshold bleaching temperature and prometryn exposure on the coral Galaxea fascicularis.
Li S, Zhou Y, Niu H … +4 more , Kang W, Fu G, Hu B, Zhao H
Mar Environ Res · 2026 May · PMID 42184790 · Publisher ↗
Ocean warming events increasingly co-occur with coastal agrochemical pollution, yet their joint effects on coral holobiont molecular responses remain poorly resolved. We exposed the reef-building coral Galaxea fascicular...
Ocean warming events increasingly co-occur with coastal agrochemical pollution, yet their joint effects on coral holobiont molecular responses remain poorly resolved. We exposed the reef-building coral Galaxea fascicularis to near-threshold warming (30 °C), prometryn (1 μg L), and their combination for 4 days, and quantified coral host and Symbiodiniaceae protein abundance using TMT-based proteomics to capture early-stage molecular responses. Heat was the primary driver of proteome shifts, consistent with suppressed biosynthesis and reallocation toward maintenance, whereas prometryn imposed additional changes on specific pathways under heat. Under combined stress, symbionts showed a mismatch in which light harvesting increased without a proportional rise in reaction-center/electron-transport capacity, which may elevate excitation pressure and oxidative stress risk. Consistent with this interpretation, photophysiological measurements showed that light-adapted PSII parameters were more responsive than dark-adapted maximum photosystem II quantum yields (Fv/Fm) during acute exposure, with the combined treatment showing modest but the clearest decline in photochemical performance. In parallel, host stress-associated signaling pathways were enriched, while antioxidant/detoxification functions were reduced in both partners. Together, these proteomic patterns suggest that prometryn exposure may compromise glutathione-based redox buffering capacity, thereby weakening the molecular response of a relatively heat-tolerant coral to near-threshold warming. The present study provides valuable insights into the critical need to prioritize the reduction of PSII herbicide pollution as part of coral reef protection strategies. Our findings support management efforts to reduce coastal PSII herbicide inputs as a local lever that could mitigate bleaching susceptibility under warming.
Spectral response of Siderastrea sp. corals under varying Iron concentrations during a Mesocosm Experiment.
Gomes PH, de Magalhães Neto N, Evangelista H … +10 more , Oaquim ABJ, Grillo AC, YumiInagaki K, Salvi KP, Lacerda CHF, Bianchini A, Costa PG, Mies M, Cordeiro RC, Vidal TJ
Mar Environ Res · 2026 May · PMID 42184789 · Publisher ↗
Coral reefs are among the most biodiverse marine ecosystems, providing essential services such as coastal protection, fisheries support, and nutrient cycling. Owing to their physiological sensitivity, reef-building coral...
Coral reefs are among the most biodiverse marine ecosystems, providing essential services such as coastal protection, fisheries support, and nutrient cycling. Owing to their physiological sensitivity, reef-building corals are widely recognized as bioindicators of changes in water quality and nutrient availability. Iron is an essential micronutrient that plays a central role in coral-dinoflagellate symbiosis by regulating metabolic and photosynthetic processes. However, the combined spectral and trophic responses of corals to iron enrichment remain poorly understood, particularly in Southwestern Atlantic reef systems. This study investigated the effects of increasing dissolved iron (DFe) concentrations (0, 100, 300, and 900 μg L) on the spectral and trophic responses of the coral Siderastrea sp. during a 28-day mesocosm experiment under semi-natural conditions. Physiological performance was assessed using handheld spectroradiometry targeting wavelengths associated with photosynthetic pigments, and trophic strategies were evaluated through fatty acid biomarkers, including the Photoautotrophic Trophic Marker Index (PTMI). Results revealed a dose-dependent spectral response to iron enrichment. Higher DFe concentrations (300 and 900 μg L) were associated with lower reflectance values across the visible spectrum (400-700 nm), indicating increased light absorption consistent with higher pigment density. In contrast, fatty acid profiles and PTMI values remained stable across treatments, indicating no significant shift in trophic strategy over the experimental period. These findings demonstrate that iron enrichment induced measurable dose-dependent increases in photosynthetic pigmentation without trophic displacement, and highlight the potential of combining spectroradiometry and biochemical trophic markers as non-invasive tools for monitoring subtle coral physiological responses under controlled micronutrient enrichment.
Mitochondrial dysfunction and DNA damage reveal nanoplastic-induced cytotoxicity in the sea cucumber Apostichopus japonicus.
Zhou Q, Gu Y, Sun B … +7 more , Ni L, Liu P, Xu D, Du J, Li X, Song Y, Xia B
Mar Environ Res · 2026 May · PMID 42176698 · Publisher ↗
Nanoplastics (NPs), as an emerging class of pollutants, have become pervasive in marine environments due to the fragmentation of larger plastic debris and intentional production for industrial applications. In this study...
Nanoplastics (NPs), as an emerging class of pollutants, have become pervasive in marine environments due to the fragmentation of larger plastic debris and intentional production for industrial applications. In this study, we investigated the cytotoxic effects of NPs on intestinal and respiratory tree cells of the sea cucumber Apostichopus japonicus, focusing on oxidative stress, mitochondrial integrity, and DNA damage. Cells were exposed to 100 nm NPs dispersed in culture media at concentrations of 0.1, 1.0 and 10.0 μg mL for 24 h, with untreated cells serving as the control. Transmission electron microscopy revealed progressive cell membrane rupture, extensive vacuolation, and the presence of bilayered autophagy-like structures and monolayered lysosome-like vesicles following NP exposure. TUNEL assays revealed a significant increase in TUNEL-positive DNA fragmentation across PS-NP exposure levels, suggesting enhanced apoptosis-like cell death. A 1.0-1.4-fold increase in ROS production confirmed that NPs induced significant oxidative stress. Mitochondrial disruption was evident by increased ADP levels and reduced ATP content, oxygen consumption rate, and activities of respiratory chain complex I-V, suggesting impaired oxidative phosphorylation. Transcriptomic analysis further supported the involvement of mitochondrial pathways in NP-induced apoptosis. Moreover, after 24 h of exposure, both olive tail moment (with an 8.0-11.8-fold increase) and DNA-protein crosslinking (25.7-30.2%) were markedly elevated, even at the lowest NP concentration of 0.1 μg mL, demonstrating substantial genotoxic effects. Overall, NPs induced cytotoxicity and apoptosis in A. japonicus cells in a dose-dependent manner, with time-dependent changes in mitochondrial function. These findings highlight the sensitivity of A. japonicus cells to nanoplastic exposure and propose cellular response indicators such as ROS accumulation, ATP/ADP imbalance, and MPTP opening as potential biomarkers for ecological risk assessment in marine benthic systems.
Artificial reefs alter viral communities and functional traits in coastal waters.
Yao J, Zhu T, Tian W … +3 more , Xu J, Nie M, Wan J
Mar Environ Res · 2026 May · PMID 42176697 · Publisher ↗
Artificial reefs (ARs) are widely deployed as engineered coastal structures to enhance habitat complexity and support marine resource management, yet their impacts on marine viral ecology remain poorly understood. Viruse...
Artificial reefs (ARs) are widely deployed as engineered coastal structures to enhance habitat complexity and support marine resource management, yet their impacts on marine viral ecology remain poorly understood. Viruses regulate microbial communities and biogeochemical processes, and their functional traits are sensitive to environmental change. Here, we investigated how artificial reefs influence viral community composition, functional gene profiles, and virus-environment interactions across paired reef and non-reef sites in coastal shelf systems. Using an integrated viromic and metagenomic approach, we compared viral assemblages in both seawater and sediments under artificial reef influence. ARs significantly modified seawater physicochemical conditions, including pH, sulfate concentration, dissolved oxygen, and salinity, whereas sediment properties remained largely unchanged. These environmental differences coincided with distinct virus-environment association patterns across habitats. Notably, artificial reefs were associated with viral functional profiles characterized by a reduced genomic representation of lysis-related genes and an increased representation of genes involved in DNA replication and nucleotide metabolism. Network analyses further showed differences in the balance of positive and negative virus-host correlations between AR and non-AR sites. Together, these results indicate that engineered coastal structures are linked to habitat-specific patterns in viral functional traits and virus-host associations. Our findings highlight viruses as sensitive indicators of anthropogenic habitat modification and underscore the importance of incorporating viral dynamics into assessments of microbial and biogeochemical responses in engineered coastal ecosystems.
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