Marine Environmental Research[JOURNAL]
Sun
200 papers
Do vertebrate-type steroids play a role in bivalve reproduction? A case study across two reproductive cycles of Magallana gigas.
Rato A, Joaquim S, Da Silva JP … +3 more , Anjos C, Matias D, Hubbard PC
Mar Environ Res · 2026 Jun · PMID 42308901 · Publisher ↗
In bivalves, reproduction is regulated by a complex interaction between endogenous and environmental factors, including temperature and food availability. However, hormonal control of the reproductive cycle in bivalves i...
In bivalves, reproduction is regulated by a complex interaction between endogenous and environmental factors, including temperature and food availability. However, hormonal control of the reproductive cycle in bivalves is poorly understood. There is a general belief that vertebrate-type steroids (testosterone, progesterone and 17β-oestradiol) are involved in the reproductive cycle of bivalves, even though the necessary enzymes and receptors for such steroids are apparently lacking in the molluscan genome. To investigate the potential role of vertebrate-type steroids in reproduction, the current study characterized two consecutive reproductive cycles of the Pacific oyster (Magallana gigas), integrating biochemical composition, reproductive indices, environmental parameters, and steroid levels. Gonadal index (GI), gonadosomatic index, and condition index exhibited clear seasonal fluctuations. Protein, glycogen, and total lipid displayed distinct seasonal patterns, with protein exhibiting structural functions, whereas glycogen and total lipid acted as energy reserves supporting gametogenesis. Both progesterone (0.69-142.33 ng g) and testosterone progesterone (2.55-262 ng g) levels fluctuated during sampling; progesterone showed correlations with GI, temperature, and protein content, whereas testosterone was mainly associated with environmental factors. These patterns suggest that progesterone may reflect gonadal tissue development and energetic investment rather than acting as a classical sex steroid. The absence of sex-specific steroid patterns, together with the lack of classical steroid receptors in the molluscan genome, supports the hypothesis of an environmental origin and/or an eco-physiological rather than an endocrine role for vertebrate-type steroids in oysters. These findings demonstrate that hormonal studies in bivalves should integrate biochemical, reproductive, and environmental data to understand reproductive strategies.
Shallow benthic Antarctic food webs recover complexity after disturbance.
Zwerschke N, Cobain MRD, Morley SA … +4 more , Peck LA, Newton J, Barnes DKA, Hill SL
Mar Environ Res · 2026 Jun · PMID 42308900 · Publisher ↗
Natural disturbance events are expected to increase with climate change. This is particularly evident in polar regions where reduced winter sea-ice has increased movement of icebergs, and thus seafloor scouring. This pre...
Natural disturbance events are expected to increase with climate change. This is particularly evident in polar regions where reduced winter sea-ice has increased movement of icebergs, and thus seafloor scouring. This predominantly affects shallow near-coast habitats, where iceberg scours can decimate local benthic ecosystems. Various metrics can be employed to measure recovery and resilience of ecosystems affected by disturbance. Here, we build a food web model for a near-shore benthic ecosystem along the West Antarctic Peninsula to evaluate the ecosystem's response to iceberg scouring and predict its response to increasing future impacts. The overall food web structure was consistent with other Antarctic benthic food webs with a low mean trophic level and connectance, a high degree of omnivory and similar average path length compared to more temperate systems. We show that chronically disturbed shallow (5 m) habitats had lower food web complexity than deeper (10-25m) habitats where disturbance intensity and frequency was reduced. Recovery with time since last disturbance showed that recently disturbed food webs had similar levels of complexity to those that had been undisturbed for 8+ years but complexity fell to a minimum after 2 years of disturbance before recovering gradually. This might be due to the influx of mobile scavengers immediately post scour. We identified some highly connected species within the food web that are found across most of the Antarctic coastal shallows, such as the starfish Odontaster validus, and conclude that these may be key to maintaining resilience in these ecosystems with increasing climate change.
Habitat-forming species as microclimatic refuges for intertidal organisms-a review and meta-analysis.
Schaefer N, Vadillo-Gonzalez S, Bishop MJ
Mar Environ Res · 2026 Jun · PMID 42302658 · Publisher ↗
The persistence of species in stressful environments can be dependent on the availability of microhabitat refuges. On intertidal rocky shores, habitat-forming species, such as seaweeds and bivalves, can provide thermally...
The persistence of species in stressful environments can be dependent on the availability of microhabitat refuges. On intertidal rocky shores, habitat-forming species, such as seaweeds and bivalves, can provide thermally stable and moist microhabitats that protect inhabitants from environmental extremes. It is, however, unclear how the protective functions of intertidal habitat-forming species vary among groups of habitat-forming species or across environmental gradients (e.g., shore height, latitude). We undertook a systematic review and meta-analysis of existing literature on effects of intertidal habitat-forming species (seaweeds, bivalves, barnacles, polychaetes) on microclimate (temperature, moisture, humidity), comparing effect sizes across taxonomic groups and environmental settings (temperature only). We identified 30 studies assessing effects of habitat-forming species on microclimates, including 29 studies measuring temperature, 6 measuring substrate moisture, and 3 air humidity. Studies were predominantly from mid-intertidal shore heights and temperate and sub-tropical regions, with only a single study from the tropics. The meta-analysis (based on 15 studies) showed that habitat-forming species significantly reduced maximum temperatures compared to bare plots, and that this effect size was similar between seaweeds and bivalves. There was a trend for greater effect sizes high on the shore, and at lower latitudes. Major gaps in the functional groups of habitat-formers and locations studied were found with limited identification of sources of variation across habitat-former effects. Advancing our understanding of how habitat-forming species shape microclimates across different environmental settings is critical to informing climate change adaptation strategies for biodiversity.
Gill dysfunction and metabolic disruption: the size-dependent effects of microplastics on Chiromantes haematocheir.
Tay Y, Liang J, Yang Y … +9 more , Ren D, Ma X, Bao M, Zhou Z, Han M, Li Z, Abdullah ALB, Gao T, Jiang Q
Mar Environ Res · 2026 Jun · PMID 42302657 · Publisher ↗
Plastic particles are emerging aquatic pollutants, but their size-associated effects on crab gill toxicity remain unclear. In this study, Chiromantes haematocheir was exposed to polystyrene particles of 75 nm, 500 nm, an...
Plastic particles are emerging aquatic pollutants, but their size-associated effects on crab gill toxicity remain unclear. In this study, Chiromantes haematocheir was exposed to polystyrene particles of 75 nm, 500 nm, and 1000 nm for 21 days to evaluate gill accumulation, oxidative stress, immune response, energy metabolism, and apoptosis. Polystyrene particles accumulated in the gills and induced tissue injury and apoptotic cell death, with PS75 causing the most severe damage. Biochemical assays showed that PS exposure disturbed glycolytic enzyme activities, antioxidant defence, and immune-related indicators. Transcriptomic analysis further revealed that different particle sizes affected pathways related to glycolysis, oxidative phosphorylation, mitochondrial electron transport, antioxidant response, immune regulation, and apoptosis. PS75 induced the strongest metabolic reprogramming, oxidative stress, and apoptotic activation, whereas PS1000 showed stronger compensatory antioxidant and mitochondrial responses. Overall, these results indicate that polystyrene particles induce size-associated gill toxicity in C. haematocheir, with smaller particles causing greater physiological and molecular disruption.
Seasonal variation of fish biodiversity in Xisha Islands based on dual-marker eDNA metabarcoding.
Deng S, Ye Y, Liu M … +9 more , Lin BA, Ma C, Xu Y, Zhou Y, Wang S, Guo W, Ou H, Zhang X, Li J
Mar Environ Res · 2026 Jun · PMID 42296681 · Publisher ↗
Environmental DNA (eDNA) is increasingly used for assessing marine biodiversity, yet its potential for monitoring seasonal dynamics in tropical coral reef ecosystems requires further systematic investigation. This study...
Environmental DNA (eDNA) is increasingly used for assessing marine biodiversity, yet its potential for monitoring seasonal dynamics in tropical coral reef ecosystems requires further systematic investigation. This study applied dual mitochondrial marker (Cytb and 12S rRNA) eDNA metabarcoding to systematically analyze fish biodiversity and community dynamics in spring (March 2021) and winter (January 2022) at Xisha Islands, a typical coral reef ecosystem in the South China Sea. A total of 432 fish species from 89 families were identified, with a stable core assemblage accounting for 64.81% of all species across both seasons. Community structure differed between seasons (ANOSIM, R = 0.375, p < 0.001). eDNA metabarcoding effectively detected cryptobenthic, deep-sea, and pelagic species that may be underdetected by established survey methods. Based on relative abundance, fish composition at Xisha Islands is dominated by Scaridae (parrotfishes) and Acanthuridae (surgeonfishes), consistent with previously documented local trophic transitions (from carnivore-dominated to herbivory-prevalent ecosystem) in this area. The dual-marker eDNA metabarcoding enhanced the efficiency of species detection, increasing taxonomic coverage by 54.38% (spring) and 62.50% (winter) compared to single markers, while mitigating primer bias and database limitations. Our results confirm that eDNA metabarcoding is an effective tool for monitoring fish biodiversity and community dynamics in remote and complex marine ecosystems. This study establishes critical baseline data for Xisha Islands coral reef ecosystem and provides a validated dual-marker framework aimed at supporting the effectiveness assessment and adaptive management of marine protected areas.
Application of environmental DNA technology in monitoring species diversity at multiple biological groups in marine protected area.
Zhang Y, Jia H, Men W … +1 more , Zhang H
Mar Environ Res · 2026 Jun · PMID 42296680 · Publisher ↗
Marine Protected Areas (MPAs) require reliable biodiversity baselines to support effective conservation and adaptive management. In this study, environmental DNA (eDNA) metabarcoding was used to assess multi-taxa biodive...
Marine Protected Areas (MPAs) require reliable biodiversity baselines to support effective conservation and adaptive management. In this study, environmental DNA (eDNA) metabarcoding was used to assess multi-taxa biodiversity in the Binzhou Shell Island and Wetland National Nature Reserve. A total of 20 surface and bottom-water samples were collected from ten sampling stations, and 123 fish species, 186 phytoplankton species and 82 invertebrate species were detected. The eDNA results revealed some degree of vertical differentiation among taxonomic groups, with phytoplankton showing clearer depth-related variation, while fish and invertebrate assemblages exhibited comparatively weaker vertical differentiation. Along the nearshore-offshore gradient, phytoplankton and invertebrates showed more evident variation in α-diversity patterns than fish communities. Cross-taxon comparisons indicated closer diversity coupling between phytoplankton and invertebrates. Environmental analyses further suggested that local physicochemical gradients, including temperature, turbidity, chlorophyll-a and water depth, may represent potential environmental correlates of community variation across different biological groups. Compared with recent fisheries records from Bohai Bay, several commercially important and small-bodied fish species, including Setipinna taty, Konosirus punctatus and Thryssa kammalensis, were recorded within the reserve, suggesting that the reserve may provide suitable habitat conditions for regional aquatic biodiversity. Overall, this study provides an initial eDNA-based biodiversity baseline for the reserve and demonstrates the value of multi-marker eDNA metabarcoding as a low-impact tool for biodiversity monitoring in shallow coastal MPAs.
Air temperature in fringe habitats: performance of climate reanalysis on Atlantic Patagonian rocky shores.
Robert MR, Pessacg N, Livore JP … +1 more , Mendez MM
Mar Environ Res · 2026 Jun · PMID 42287877 · Publisher ↗
Climate change and especially extreme events are affecting the distribution and abundance of species, with consequences on ecological processes and community structure. Long-term records of environmental parameters are i...
Climate change and especially extreme events are affecting the distribution and abundance of species, with consequences on ecological processes and community structure. Long-term records of environmental parameters are indispensable in climatological studies to better understand the processes involved. Such data is usually unavailable, like for Patagonian intertidal shores in the Southwestern Atlantic. The use of reanalysis products can help elucidate the climate of the past when in situ information is missing. In this work, we test the performance of reanalysis datasets in reproducing air temperature patterns and extreme heat events (heatwaves) on Atlantic Patagonia rocky intertidal. Thus, we evaluate the degree of correlation between reanalysis products and air temperature data from loggers placed on rocky shores. We also test whether those products accurately detect the duration, frequency and number of heatwaves and look for historical trends in their features. Our results showed that reanalysis products perform well for assessing broad-scale changes in temperature patterns. Products were also capable of detecting heatwaves, with little variation in their features for the 1960-2024 period. Additionally, real-time field temperatures to which intertidal organisms are exposed were obtained for the first time in the area; reporting heatwaves events. Thereby, reanalysis products complement local data, providing key information to understand the role that temperature increases and extreme heat can play in ecological processes. This work provides empiric evidence on the usefulness of reanalysis products of intertidal habitats and encourages similar approaches to properly understand climatological patterns that can drive ecological processes.
Resilience of submarine groundwater discharge to extreme drought in a large river-dominated estuary: A case study of the Changjiang Estuary.
Wu H, Liu J, Wu H … +3 more , Wang J, Zhang F, Du J
Mar Environ Res · 2026 Jun · PMID 42287876 · Publisher ↗
Submarine groundwater discharge (SGD) is a major chemical source to coastal ecosystems due to its large, nutrient-rich fluxes. However, its response to extreme drought remains unclear. Herein we investigated SGD in the C...
Submarine groundwater discharge (SGD) is a major chemical source to coastal ecosystems due to its large, nutrient-rich fluxes. However, its response to extreme drought remains unclear. Herein we investigated SGD in the Changjiang Estuary (CJE) during the 2022 extreme drought using radium mass balance (Ra, Ra) and three end-member mixing models. These two different models yielded consistent estimates, with an average SGD flux of (1.5 ± 0.7) × 10 m d (13.6 ± 6.4 cm d) for the CJE during the extreme drought. This flux was comparable to the range observed during normal dry season levels (18.4-44.0 cm d) but 4.4-22.7 times higher than the wet-season fluxes (0.6-3.1 cm d), demonstrating substantial resilience under drought conditions. During the extreme drought, SGD and riverine input were the dominant source of nutrients in the CJE, contributing approximately 96% of the total DIN and DIP fluxes. The large amount of dissolved DIN ((2.5 ± 1.9) × 10 mol d) and DIP ((2.0 ± 1.4) × 10 mol d) fluxes together with high N: P ratios (178:1) into the CJE would potentially exacerbate eutrophication, hypoxia, and harmful algal blooms.
Bacterial communities and antibiotic resistance genes in seawater adjacent to inhabited and uninhabited xisha coral reef islands: Insights from 16S rRNA and metagenomic sequencing.
Yang X, Wu P, Li C … +10 more , Zheng Q, Shi X, Su H, Wang T, Xiong X, Liu Y, Xiao Y, Xu S, Zou J, Liu Y
Mar Environ Res · 2026 Jun · PMID 42287875 · Publisher ↗
The Xisha coral reefs are highly biodiverse ecosystems in the South China Sea, China. Bacterial communities drive energy flow and biogeochemical cycling in coral-reef ecosystems, and serve as indicators of reef health. Y...
The Xisha coral reefs are highly biodiverse ecosystems in the South China Sea, China. Bacterial communities drive energy flow and biogeochemical cycling in coral-reef ecosystems, and serve as indicators of reef health. Yet the composition and dynamics of both bacterial assemblages and ARGs within the Xisha coral reefs remain poorly resolved. This study used 16S rRNA amplicon and metagenomic sequencing to compare bacterial community structure across surface and bottom waters, and surface-water ARGs profiles, in Beijiao Reef (BJ; an uninhabited reef) and Qilianyu Islands (QLY; an inhabited island) of the Xisha Islands. The results revealed bacterial community composition, bacterial co-occurrence network structure, and ARGs profiles differed markedly between the two reef areas. Dominant genera-Prochlorococcus_MIT9313, Salinimonas, Synechococcus_CC9902, Vibrio, and Alteromonas-were significantly more abundant in BJ (p < 0.05), whereas QLY showed higher abundances of Planococcus, Psychrobacter, Jeotgalibacillus, Salinicoccus, and Marinococcus (p < 0.05). The QLY bacterial co-occurrence network exhibited greater complexity (higher clustering coefficients and modularity), whereas the BJ network was simpler but displayed significantly higher closeness-centrality values (p < 0.001). Surface waters of the Xisha Islands were dominated by tetracycline, aminoglycoside, and macrolide resistance genes, whereas sulfonamide and multidrug resistance genes were less abundant. In addition, ARGs concentrations in BJ were slightly higher than those in QLY, suggesting that human habitation may not be a key environmental factor influencing ARGs concentrations in the seawater of the Xisha Islands. Correlation analysis showed that high-abundance ARGs in BJ (msbA, RanA, tetB(P), tet(T)) were linked to phototrophic Prochlorococcus_MIT9313 and Synechococcus_CC9902, whereas QLY dominant ARGs (baeS, patB, MexW) correlated with Gram-negative Vibrio and Pseudomonas. These ARGs are involved in bacterial efflux mechanisms, reflecting adaptive responses to environmental stress. This study provides valuable insights for assessing water quality and evaluating the impacts of human habitation pressure on coral reef ecosystems in the Xisha Islands.
Sunscreen pollution alters the role of detached seagrass leaves in the coastal carbon cycle.
Vilaplana MI, Jiménez-Ramos R, Rodríguez-Romero A … +3 more , Fortunato A, Vergara JJ, Egea LG
Mar Environ Res · 2026 Jun · PMID 42287874 · Publisher ↗
Seagrass macrophytodetritus plays a crucial role in coastal carbon dynamics, but little is known about primary production and dissolved organic carbon (DOC) release from freshly detached leaves and their associated micro...
Seagrass macrophytodetritus plays a crucial role in coastal carbon dynamics, but little is known about primary production and dissolved organic carbon (DOC) release from freshly detached leaves and their associated microbiome. Although this detritus is often exposed to sunscreen pollution in shallow coastal areas, the effects of sunscreen-derived compounds on macrophytodetritus decomposition also remain largely unknown. In this study, we exposed freshly detached leaves of the seagrass Cymodocea nodosa to a mixture of five commercial sunscreens in a 63-day mesocosm experiment. In the control treatment, leaves exhibited measurable primary production net biomass change, and net DOC release, throughout the experiment. Much of this production was attributed to residual photosynthetic activity in the leaves and a high relative abundance of phototrophic bacterial families in the phyllosphere microbiome. In contrast, sunscreen exposure caused severe metabolic disruption, accelerating necrosis, promoting DOC consumption until day 40, and shifting the leaf carbon metabolism towards net heterotrophy. These results demonstrate that freshly detached seagrass leaves are an active and dynamic component of coastal carbon cycling. Our results also reveal how sunscreen pollution associated with coastal tourism can alter the role of seagrass detritus as a source of DOC, trophic subsidies, and potential precursor to long-term oceanic carbon sequestration.
Zinc isotopes in muscle tissues as a novel niche tracer for elasmobranchs: a proof-of-concept study.
Queiroz APN, Jeong H, Garnier J … +3 more , Ra K, Lessa RPT, Araújo DF
Mar Environ Res · 2026 Jun · PMID 42287873 · Publisher ↗
Stable zinc isotopes (δZn) have recently emerged as promising ecological tracers, yet their application in elasmobranchs remains limited. Here, we evaluated the use of δZn in elasmobranch muscle tissue in combination wit...
Stable zinc isotopes (δZn) have recently emerged as promising ecological tracers, yet their application in elasmobranchs remains limited. Here, we evaluated the use of δZn in elasmobranch muscle tissue in combination with traditional isotopes (δC and δN) to compare isotopic variability among three sympatric stingray species inhabiting a heterogeneous coastal system along the Brazilian coast. The analyses revealed species-specific δZn patterns and differences in multitracer isotopic space among species. Hypanus guttatus exhibited broader isotopic variability than Hypanus marianae and Hypanus berthalutzae, which showed more constrained and partially overlapping isotopic patterns. Compared with δC and δN, δZn exhibited partially distinct isotopic behaviour, suggesting sensitivity to a more complex combination of trophic, environmental, and physiological influences. This additional isotopic variability contributed complementary information to species discrimination. Overall, our results suggest that Zn isotopes in soft tissues represent a promising addition to multitracer isotopic approaches in marine predators.
Divergent responses of prokaryotic and eukaryotic microbiomes drive assembly, stability, and functional dynamics in the Bohai sea.
Wu J, Wang B, Li Y … +8 more , Zhang X, Peng Y, Liu Q, Zhang C, Lian B, Cao H, Li K, Wang H
Mar Environ Res · 2026 Jun · PMID 42287872 · Publisher ↗
Coastal oceans, critical for biodiversity and biogeochemistry, are increasingly altered by anthropogenic pressures that interact with natural spatiotemporal variability. However, the relative influence of spatial versus...
Coastal oceans, critical for biodiversity and biogeochemistry, are increasingly altered by anthropogenic pressures that interact with natural spatiotemporal variability. However, the relative influence of spatial versus temporal drivers on microbiomes assembly, association, and function remains unclear. To resolve this, we integrated multi-kingdom amplicon and metagenomic sequencing to analyze microbial communities across spatial (Laizhou Bay vs. open Bohai Sea) and temporal (seasonal to interannual) gradients in the Bohai Sea, a semi-enclosed coastal system heavily influenced by recurrent human activities. Our results demonstrate that temporal variation exerts relatively stronger influences than spatial heterogeneity on the structure and dynamics of microbial communities in the Bohai Sea. Microeukaryotes exhibited the greatest responsiveness to spatiotemporal change, followed by archaea, with bacteria showing the highest stability. Archaeal and microeukaryotic communities were primarily governed by stochastic processes, whereas bacterial assembly transitioned from deterministic to stochastic control along spatiotemporal gradients. Microbiome co-occurrence networks were increasingly complex but less stable under spatiotemporal variability, dominated by competitive interactions and demonstrating a clear complexity-stability trade-off. Metagenomic analysis revealed a scale-dependent hierarchy of environmental drivers regulating metabolic pathways, with temperature predominant at the regional scale, DO in summer, and DON within homogeneous sub-regions. Two parallel microbial strategies for coping with anthropogenic pressure were identified, including enhanced catabolic pathways for xenobiotic degradation and a seasonally dynamic, mobile antibiotic resistome. This study provides a multidimensional and systematic perspective by demonstrating that temporal dynamics are the principal regulator of coastal microbiomes structure, stability, and function, with critical implications for predicting the responses of anthropogenically stressed coastal ecosystems under continuous environmental change.
Development and validation of a ddPCR & viability PCR assay for enhancing eDNA benthic surveys: A deep-sea case study.
Laroche O, Downes P, Middelboe M … +4 more , O'Malley B, Thompson-Laing J, Sissons J, von Ammon U
Mar Environ Res · 2026 Jun · PMID 42287871 · Publisher ↗
Environmental DNA metabarcoding represents a powerful and cost-efficient approach for benthic microbial surveys, but is limited by the lack of absolute abundance information, and by the conflation of contemporary and leg...
Environmental DNA metabarcoding represents a powerful and cost-efficient approach for benthic microbial surveys, but is limited by the lack of absolute abundance information, and by the conflation of contemporary and legacy DNA. In this study, we explored the combined use of a propidium-monoazide (PMA) treatment, 16S rRNA ddPCR and metabarcoding to assess the microbial density, composition and diversity of contemporary communities, and estimate the proportion of legacy DNA in deep-sea surface sediment. We used spike-in synthetic DNA to assess the efficiency of the PMA treatment and validated results against flow cytometry (FC) and environmental data. Overall, the efficiency of the PMA treatment was moderate (mean of 45%) and highly correlated with the proportion of extracellular DNA in the samples (r = -0.95). Microbial density estimates from ddPCR correlated weakly with FC results (r = 0.25), but strongly with sediment depth (r = -0.5) and dissolved oxygen (r = 0.56). Accounting for PMA treatment efficiency, legacy DNA amounted to approximately half of total microbial DNA. Comparison of eDNA, eRNA and PMA-treated eDNA (iDNA) microbial assemblages indicated substantially stronger correlation of the later with environmental data, followed by eDNA. Overall, this study provides encouraging results for the application of PMA treatment on sediment samples and the use of ddPCR-based microbial density estimates, but also highlight the need for protocol optimization and further validation to obtain better performance and further confidence.
Impacts of phytoplankton blooms on the benthic phosphorus cycle in a coastal ecosystem (Bay of Vilaine, France).
Ratmaya W, Andrieux-Loyer F, Rabouille C … +5 more , Collin K, Caradec F, Laverman AM, Barillé L, Souchu P
Mar Environ Res · 2026 Jun · PMID 42284673 · Publisher ↗
Temporal and spatial variations in benthic phosphorus (P) cycle were studied in the eutrophic temperate macro-tidal Vilaine Bay (VB) using field observations, laboratory measurements and an early diagenetic model. Time s...
Temporal and spatial variations in benthic phosphorus (P) cycle were studied in the eutrophic temperate macro-tidal Vilaine Bay (VB) using field observations, laboratory measurements and an early diagenetic model. Time series of sedimentary P speciation, benthic fluxes measurements and dissolved P pore water profiles at a monitoring station, together with a spatial survey, were complemented by an extensive set of physical, chemical, and biological descriptors of the water column. Benthic dissolved inorganic P (DIP) fluxes ranged from 0.5 to 7.0 μmol m h, while benthic dissolved organic P (DOP) fluxes remained weak and lacked a clear pattern, likely due to rapid microbial turnover of a labile DOP pool, contributing indirectly to DIP regeneration. Sedimentary P was dominated by Organic P (Org-P) and iron oxides-bound P (Fe-P). The model correctly reproduced observed variations in benthic DIP fluxes and identified phytoplankton-derived Org-P mineralisation and the Fe-P formation/dissolution balance as the main controls on benthic P dynamics. In spring, a fraction of DIP produced by bloom mineralisation was temporarily retained in sediments through Fe-P formation. This P was subsequently released during summer as bottom-water oxygen saturation decreased, promoting Fe-P dissolution. In summer, increased organic matter degradation further elevated sediment oxygen demand, enhancing DIP release through Fe-P dissolution and ongoing Org-P mineralisation. Benthic DIP release therefore constitutes a sustained internal P source that can prolong summer phytoplankton biomass and potentially exacerbate the effects of riverine nutrient inputs. These results highlight that reducing nitrogen inputs is necessary to mitigate eutrophication in coastal waters.
The response of the bacterial community to long-term pollution in coastal sediment cores.
Chen J, Su Z, Li F … +4 more , Zheng Y, Jiang B, Xing Y, Wen D
Mar Environ Res · 2026 Jun · PMID 42284672 · Publisher ↗
Coastal sediments are vital yet vulnerable interfaces of pollutant transformation and microbial activity. However, the response of coastal bacterial community to accumulating environmental pollution over time remains poo...
Coastal sediments are vital yet vulnerable interfaces of pollutant transformation and microbial activity. However, the response of coastal bacterial community to accumulating environmental pollution over time remains poorly resolved. Our study unraveled four decades from 1980 to 2020 of pollution dynamics and bacterial adaptation in coastal ecosystems by analyzing sediment cores. The concentrations of most detected contaminants exhibited a temporal increase as a function of core age, particularly for the heavy metals. Concurrently, bacterial alpha-diversity increased over time, accompanied by significant structural reorganization of community. In total, 16 bacterial metabolic pathways were predicted, with the majority intensifying over time. Bacterial networks displayed marked declines in complexity and stability under increasing pollution, and partial post-2000 enhancement remained below 1980-1990 baseline. Heavy metals emerged as the dominant stressor, profoundly shaping community composition and functional profiles. Notably, K-strategists demonstrated superior adaptation to heavy metals over r-strategists, reflecting their resilience in environment with resource-limited and high-stress. Our findings link the accumulated contamination to reorganized diversity, altered functionality, and reconfigured co-occurrence patterns, underscoring the dynamic adaptive strategies of coastal bacterial community to chronic pollution.
Non-consumptive effects of predator and conspecific exudates on different stages of an encapsulating gastropod.
Muñoz-Valdés JJ, Jaramillo HN, Paredes-Molina FJ … +5 more , Sabja-Llanos EN, Manzano ME, Pardo LM, Averbuj A, Chaparro OR
Mar Environ Res · 2026 Jun · PMID 42284671 · Publisher ↗
Prey can detect chemical cues from predators or injured conspecifics, triggering non-consumptive effects (NCEs) that influence behavior, physiology, or life-history traits. This study examined NCEs on the slipper limpet...
Prey can detect chemical cues from predators or injured conspecifics, triggering non-consumptive effects (NCEs) that influence behavior, physiology, or life-history traits. This study examined NCEs on the slipper limpet Crepipatella peruviana by measuring oxygen consumption rate (OCR) and clearance rate (CR) at three life stages (encapsulated larvae, males, and females). Individuals were exposed to exudates from two predators: the seastar Meyenaster gelatinosus (a top predator in wave-exposed coastal environments) and the gastropod Argobuccinum pustulosum (a sympatric predatory snail), as well as from injured conspecifics. We also assessed the actual predation capacity and attack rates of both predators on C. peruviana. Results showed no NCEs induced by M. gelatinosus exudates, likely due to habitat segregation preventing prey recognition. Conversely, exposure to A. pustulosum exudates increased OCR in larvae and females and increased CR in males, while females showed decreased CR. Injured conspecific exudates caused a reduction in CR in females, without affecting OCR. Predation trials revealed M. gelatinosus attacked prey only when detached from the substrate (0.5 individuals/day), while A. pustulosum effectively attacked substrate-attached prey (0.34 individuals/day) by shell perforation. These findings suggest that C. peruviana can detect and respond physiologically to certain predator cues, potentially as escape or antipredatory mechanisms, while the absence of response to M. gelatinosus may be explained by limited ecological overlap.
ENSO-driven distribution shifts in the critically endangered Mustelus whitneyi along the Northern Peruvian Coast.
López-García J, Navia AF, Cruz-Escalona VH … +4 more , Alfaro-Shigueto J, Mangel JC, Urcádiz-Cázares FJ, Yáñez-Arenas C
Mar Environ Res · 2026 Jun · PMID 42284670 · Publisher ↗
Mustelus whitneyi (humpback smooth-hound shark) is a Critically Endangered demersal species endemic to the southeastern Pacific and exploited by small-scale fisheries in northern Peru. This study evaluated how seasonal a...
Mustelus whitneyi (humpback smooth-hound shark) is a Critically Endangered demersal species endemic to the southeastern Pacific and exploited by small-scale fisheries in northern Peru. This study evaluated how seasonal and interannual environmental variability, particularly associated with the El Niño-Southern Oscillation (ENSO), influences the spatial distribution of the species. Presence-only data collected between 2015 and 2018 were combined with six oceanographic variables selected from an initial set of eight candidate predictors from the Copernicus Marine Service to develop seasonal species distribution models (SDMs) using Maxent. To account for sampling bias associated with fisheries-dependent records, background selection was informed by a distance-based bias raster. Models performed better than random expectations in all scenarios, although performance varied among seasons and several models exhibited elevated omission rates, indicating lower predictive reliability during specific periods. Bottom potential temperature emerged as the primary environmental predictor, highlighting the importance of subsurface thermal conditions for this demersal species. Predicted suitable habitat showed seasonal and interannual variability. The largest predicted distribution areas were observed during El Niño conditions, particularly in austral spring 2015 and winter 2016, coinciding with warmer bottom waters. In contrast, neutral conditions in 2017 were associated with a contraction of suitable habitat during austral summer, whereas La Niña conditions in 2018 produced more fragmented spatial patterns. Overall, the results suggest that climate-driven environmental variability influences the spatial extent and configuration of the predicted distribution for M. whitneyi. This study provides the first ENSO-phase-specific SDMs for the species and offers a baseline for incorporating environmental variability into fisheries management and conservation planning in the Northern Humboldt Current System.
Deep-sea soft-bottom macroinfaunal communities from SE Pacific: Composition, abundance, distribution, and their relationship with environmental forcing.
Soto EH, Sanchis C, Quiroga EJ
Mar Environ Res · 2026 Jun · PMID 42284669 · Publisher ↗
Abyssal and hadal macroinfaunal communities (>300 μm) were studied across a longitudinal geographic transect in the Southeast Pacific region (71°- 109°W). Composition, structure, and distribution were analyzed in relatio...
Abyssal and hadal macroinfaunal communities (>300 μm) were studied across a longitudinal geographic transect in the Southeast Pacific region (71°- 109°W). Composition, structure, and distribution were analyzed in relation to the seafloor organic content associated with surface productivity. Sediment samples were collected at each study site with a multicore containing eight cores of 7.5 cm internal diameter, covering associated seamounts, oceanic islands, and trench environments. Faunal composition was dominated by Crustacea, Mollusca, and Annelida, with Crustacea as the most diverse. Polychaeta and Copepoda were always the most common and abundant in all sites recording a relative abundance of 38% and 33%, respectively. Vertical distribution showed that 73% of fauna inhabit the first centimeter of sediment. The number of individuals was low and mean density per site was 710 ind. m, however the high number of species recorded only once would indicate a high diversity of species in the study zone. Ecological indices showed higher values in eutrophic and mesotrophic areas coinciding with the record of the highest concentrations of parameters related to sediment organic content. Differences between habitats were observed, recording higher abundance and diversity on Trench and Seamount sites from eutrophic and mesotrophic zones, while lower values of these descriptors on Seamount and Oceanic Island sites associated with less productive zones. Statistical analysis and correlations showed that Chloroplast Pigment Equivalent and Chlorophyll-a may explain the observed patterns for the benthic community. The macroinfaunal communities described are typical of abyssal and hadal sediment environments and they appear to respond to organic inputs according to recorded spatial distribution patterns.
Environmental context modulates macrofauna mediated functioning and potential resilience of tropical marine protected areas.
Ridha H, Sukumaran S, Sneha T … +2 more , Jimmy A, Manikandan B
Mar Environ Res · 2026 Jun · PMID 42275771 · Publisher ↗
Tropical Marine Protected Areas (MPAs) face growing threats from climate change and anthropogenic pressures. Abrupt environmental changes can disrupt core ecosystem functions, eroding the functional redundancy that under...
Tropical Marine Protected Areas (MPAs) face growing threats from climate change and anthropogenic pressures. Abrupt environmental changes can disrupt core ecosystem functions, eroding the functional redundancy that underpins potential resilience. A comparative study of two contrasting Indian coralline MPAs, the Gulf of Kachchh (GoK) and the Gulf of Mannar (GoM), employing macrobenthic functional studies revealed variable resilience, modulated by the contrasting environmental contexts of the MPAs. Functional evenness and divergence were comparable between MPAs, whereas GoK exhibited higher functional dispersion and RaoQ. GoM supported higher proportion of sensitive functional modalities, while GoK showed greater representation of opportunistic modalities, consistent with differing environmental contexts. Sedimentological parameters structured trait distributions in both MPAs, with nutrients adding a region-specific influence in GoK, as revealed by RLQ and fourth-corner analyses. GoM exhibited comparatively higher functional redundancy, suggesting that multiple species may perform similar ecological roles and thereby helping to maintain ecosystem functioning even during species loss, which may indicate greater resilience. This elevated trait overlap is consistent with GoM's biologically rich environment and low environmental variability. In contrast, GoK is governed by intense evaporation, strong currents, high sedimentation and energetic semidiurnal tides. These hydrodynamically unstable and climate responsive conditions can reduce the potential resilience, rendering the GoK ecosystem more vulnerable to future climate perturbations. Integrating functional diversity indices provided critical insights into ecosystem resilience relevant to coral reef management and conservation. This study highlights that environmental context modulates potential resilience of MPAs, underscoring that protected status alone does not shield ecosystems from environmental pressures.
Eco-engineered vertical seawall panels with augmented habitat complexity can create a novel and biodiverse ecosystem in a coastal megacity.
Bradford TE, Astudillo JC, Lai C … +7 more , Leung RWS, Minuti JJ, Morris RL, Hawkins SJ, Chan JKY, Chu CKC, Leung KMY
Mar Environ Res · 2026 Jun · PMID 42269307 · Publisher ↗
Vertical seawalls are extensive and rapidly expanding in coastal cities and ports but provide inadequate habitat for intertidal fauna and flora as they lack necessary refugia from heat and desiccation stresses, lowering...
Vertical seawalls are extensive and rapidly expanding in coastal cities and ports but provide inadequate habitat for intertidal fauna and flora as they lack necessary refugia from heat and desiccation stresses, lowering intertidal biodiversity. Ecological engineering through retrofitting suitable habitats aims to promote marine biodiversity through habitat provision. Two eco-engineered panel designs with augmented habitat complexity were tested on a seawall in a highly developed subtropical marina. One panel was commercially available, with a repetitive pattern of short extrusions - the Imported Commercially Available Design (ICAD). The other was a locally designed, double-sided panel with deep intrusions and shade behind the panel - the Hong Kong Design (HKD). Taxonomic richness of the intertidal fauna and flora on the panels were compared to flat, concrete panels (flat panel, representing a worst-case scenario) and scraped seawall plots (seawall control) for 18 months. Marine biodiversity on both eco-engineered panels was significantly higher than the flat concrete panels, and the HKD was colonised by the highest taxonomic richness (64 total taxa). The HKD had greater abundance of suspension feeders, higher richness within key functional groups, and enabled colonisation at higher tidal levels compared to the flat panel and seawall control. When compared to nearby vertical seawalls, the HKD and ICAD contributed to an increased within-site β diversity and functional diversity. These results imply that implementing similar eco-engineering of grey infrastructure while reducing other anthropogenic stressors can contribute to the aim of creating biodiverse intertidal ecosystems within coastal cities and ports.
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