Frontiers in Marine Science

Introduction Razor clam ( Sinonovacula constricta ) is a bivalve of economic importance that widely resides in coastal and estuarine areas where salinity fluctuates rapidly. Gut microbiota, which plays a pivotal role in the disease resistance against pathogens and the growth and development of aquatic animals, is affected by salinityfluctuation in ambient environment. However, there is limited knowledge about the underlying mechanism of how clam gut microbiota respond to alternating salinity stress. Methods Here, we exposed S. constricta to different salinity treatments including normal salinity-acclimated (NN, 20 psu), low salinity-acclimated (LL, 5 psu), low salinity-stressed (NL, transferred from 20 to 5 psu) and normal salinity-stressed (LN, transferred from 5 to 20 psu) groups. The former two groups were used as the control, and the latter two groups aimed to investigate the effect of alternating salinity stress on clam growth and gut microbiota by 16S rRNA gene amplicon sequencing. Results Alternating salinity stress caused faster and higher mortality compared with the two control groups, and disrupted the gut microbiota including altered α-diversity, composition and structure. The salinity stress, hours post stress and their interaction had significant impact on the gut microbiota, which contributed 4.5%, 9.5% and 6.0%, respectively, to the variance in the gut communities. Alternating salinity stress increased the proportion of stochastic processes in governing the gut microbiota to a certain extent, and the stochasticity aggravated with the increase of stress time. Furthermore, the gut bacterial interspecies interaction networks exhibited more complex and higher connected topology in two alternating salinity stress groups compared with the control group (NN), and the interaction relationships between core OTUs in gut networks were altered after salinity stress. The functional potentials involved in immune system and metabolisms of amino acid, energy, carbohydrate and lipid remarkably increased in LN and NN groups after salinity exposure for 96 h compared to corresponding 0 h, while these pathways exhibited the opposite pattern in NL and LL groups. Discussion Collectively, our findings provide evidence that alternating salinity stress has potentially negative effect on the growth of S. constricta from an ecological viewpoint.

Introduction Biomass allocation between aboveground and belowground pools in salt marshes has distinct effects on salt marsh stability, and is influenced by climate warming and reproductive investment. However, the lack of studies on the effect of latitudinal variations in reproductive investments and biomass allocation in salt marshes makes it difficult to explore mechanisms of marsh plant growth to climate warming across geographical scales. The rapid invasion of the salt marsh grass Spartina alterniflora into lower latitude marshes around the world provides an opportunity to investigate biomass allocation and reproductive investment across latitudes, helping to understand how salt marshes respond to climate warming. Methods Therefore, we investigated aboveground biomass (AGB), belowground biomass (BGB), total biomass, sexual reproduction traits (inflorescence biomass, flowering culm), asexual reproduction traits (shoot number, rhizome biomass), among S. alterniflora at 19 sites in 10 geographic locations over a latitudinal gradient of ~2000 km from Dongying (37.82°N, high latitude) to Danzhou (19.73°N, low latitude) in China. Results The AGB, BGB, and total biomass displayed hump shaped relationships with latitude, but the BGB: AGB ratio decreased with increasing latitude (i.e. increased linearly with temperature). Interestingly, we found that the BGB: AGB ratio negatively correlated with sexual reproductive investment, but positively correlated with asexual reproductive investment. Discussion While conceptual and numerical models of salt marsh stability and carbon accumulation often infer responses based on aboveground biomass, our study suggests that salt marsh responses to climate warming based on aboveground biomass and static allocations may bias estimates of future salt marsh production driven by climate warming.

This paper examines the intraseasonal variabilities (ISVs) of the Wyrtki Jet in boreal spring and fall and their impacts on the oceanic ISVs along the southern coast of Sumatra-Java Island. The results reveal that the Wyrtki Jet ISVs in spring are significantly stronger than those in fall, with the standard deviation of the 0-30m-averaged zonal current reaching up to 0.25 m/s in spring, while the highest value in fall is only 0.2 m/s. The Wyrtki Jet ISVs are significantly correlated with surface zonal wind anomalies and sea level anomalies (SLAs) in the equatorial Indian Ocean (EIO) at intraseasonal timescale, and are modulated by the propagation of equatorial Kelvin waves. The intraseasonal SLAs along the southern coast of the Sumatra-Java Island are significantly correlated with the Wyrtki Jet ISVs, exhibiting similar seasonal fluctuation characteristics. In spring, the Wyrtki Jet intraseasonal signals initially appear near 75°E at the equator, approximately 10 days before the positive peaks of the intraseasonal SLAs, while in fall, the Wyrtki Jet intraseasonal signals first appear about 15 days before the peaks near 60°E at the equator, which is relatively further west compared to signals in spring. In addition, the composite Wyrtki Jet ISVs in spring are approximately 0.2 m/s stronger than those in fall. The enhanced ISVs of sea surface zonal wind forcing and Wyrtki Jet in spring, relative to those in fall, indicate that the seasonality in the intraseasonal SLAs along the southern coast of Sumatra-Java is attributable to the combined effects of surface wind forcing and current fields.

This study investigates the direct impact of green innovation in marine-related enterprises on pollution emissions, addressing a significant gap in existing research regarding the role of executives’ environmental awareness factor. Using a sample of 2,580 marine-related firm-year observations from the 2008-2022 period, we find that green innovation and improved environmental awareness among management can significantly reduce water pollution and air pollutants in enterprises and reduce the environmental problems caused by marine-related businesses. Moreover, enhancing environmental awareness within management can effectively substitute for the inhibitory effects of green innovation on pollution emissions. We conduct a heterogeneity test, and it proves that the inhibitory effects of green innovation and executives’ environmental awareness vary across industries and ownership types. These findings contribute to the literature on the sustainable development of marine enterprises.

The Venice Lagoon is the largest transitional environment within the Mediterranean Sea (almost 550 km ² ). Being a transitional environment, it contains many different ecological niches, hence the biodiversity in this environment is very high. However, at the same time, this lagoon system is under constant pressure from human activities, and it has been greatly modified by humans during the centuries. Examples are the construction of the city of Venice, the digging of the canals for commercial ships, and the modifications of the three inlets to the lagoon. All these activities altered the circulation inside the lagoon, modifying the equilibrium between river and sea inputs, also influencing the sediment intake, fundamental for saltmarshes stability. During the centuries, many authors monitored the photosynthetic taxa (seaweeds, halophytes, and seagrasses) inhabiting the Venice Lagoon. In this study, we reviewed works from the nineteenth century to the present time to obtain a complete and updated view of the photosynthetic species that inhabit this environment, observing a decrease in the presence of charophytes and heterokontophytes and an increase in rhodophytes in the analyzed period. Moreover, we also considered the ecological valence of the species reported in this environment through two different ecological indexes (Macroalgae Quality Index – MaQI, Ecological Evaluation Index – EEI), observing a decrease in the relative contribution of the species with high ecological valence along the centuries. We also reviewed the presence of threatened and non-indigenous species, observing some differences in the considered works. Finally, we also considered the molecular resources available on online databases, finding only half macroalgal species with a reference sequence, compared to almost 90% for higher plants.

N 2 O is one of the most important greenhouse gases and ozone depletor, which was a matter of more and more concerned. The Southern Ocean was considered as one of the most important N 2 O source and was believed to account for ~1/4 of oceanic budget. However, there is uncertainty about this budget due to limited data availability. In this study, field and lab works were conducted for better understanding of N 2 O dynamics during sea ice melting and sea ice formation. In the field study, taking advantage of the Chinese Antarctic cruise, a 10 days’ time series study was carried out at a station in the Prydz Bay, Antarctica, where, surface water N 2 O was observed continuously, and the adjacent ice cores were taken for N 2 O analysis. In the lab, an ice growing simulation system was constructed to study the N 2 O dynamics during the sea ice formation. The result of endmember mixing models and calculation of N 2 O partition in three phases during sea ice formation provide important information about the dynamics of N 2 O during ice melting and sea ice formation processes, that is, the sea ice melting regulated N 2 O concentration and saturation status, which can be an explanation for reported N 2 O undersaturation observed in polar oceans, whereas during the sea ice formation, most of the N 2 O will be expelled to the deeper water while a small amount of retain the sea ice and less amount of N 2 O release to the atmosphere.

The anthropogenic influences of historical shipwrecks on the marine environment remain largely uncharacterized, particularly for wrecks located at depths of~50 meters and lost over 80 years ago. Below 50 meters, the marine environment transitions from the euphotic to the mesophotic zone, where reduced light, significant changes in oxygen levels, and increased pressure may alter microbial communities and metabolic pathways. Understanding these shifts can provide insights into the adaptation and evolution of microorganisms. Sediment samples were collected by a team of divers from nine wreck sites off the coast of Malta, varying in depth from 5 to 100 meters. All sampling was conducted with the consent and authorization of the Government of Malta for the collection of marine genetic resources. Chemical analyses and metabarcoding techniques were employed to assess how shipwrecks influence microbial diversity and community composition in the surrounding sediments. Alpha (a) diversity of microbial communities was higher in sediments adjacent to the shipwrecks compared to those collected over 100 meters away from any wreck site. Across all nine wreck sites, sediment size emerged as the most significant driver of microbial diversity, followed by frame type and the presence of oil leaks. This study demonstrates that shipwrecks, varying in depth, frame type, and country of origin, significantly influence the microbial ecosystems and sediment chemistry of their surrounding environment. The findings suggest that shipwrecks act as focal points for ecological and chemical changes, contributing to the dynamic interactions between historical artifacts and marine ecosystems.

Small-scale fisheries provide seafood for billions of people and are one of the largest employers in many coastal communities. Those households engaged in these fisheries who maintain diverse income sources are generally thought to be better prepared to cope with social or ecological perturbations such as the crises presented by the COVID-19 pandemic. One outcome of the COVID-19 crisis was the collapse of international tourism after many nations instituted strict border controls to slow the virus’s spread, severely impacting coastal communities that depend on tourism-related employment. This research assessed the effects of COVID-19-induced collapse of tourism on small-scale coral reef fishers and households in Moorea, French Polynesia. Ninety-five households were surveyed about their livelihoods, fishing, demographics, and income-generating occupations before and after the lockdown. Shifts in fish biomass were evaluated using time series data collected through underwater visual surveys, and roadside fish vendors were surveyed to assess fish sales. Results showed that after tourism employment evaporated more Moorea households began fishing to boost their incomes and food security. However, the increase in fishing pressure showed no appreciable decline in the biomass of fishable species. The households responsible for the increased fishing activities were those who were working in the tourism economy prior to the pandemic and subsequently lost their jobs. Households that combined fishing with construction or other stable sectors showed greater abilities to cope, while those combining fishing with tourism were heavily impacted. Importantly, results showed that those households devoted solely to fishing managed the crisis adeptly due to their superior fishing skills and ecological knowledge. This pattern suggests that not all forms of household livelihood diversification confer equal advantages and that resource-dependent households are not necessarily intrinsically less resilient. More generally, it is argued that we should be cautious when promoting livelihood diversification as a blanket solution to decrease household vulnerability, and that ecological knowledge diversity is underappreciated.

How a pair of pollutant parcels deviates from each other with an initial separation distance r 0 , known as relative dispersion or Richardson dispersion, is relevant in many circumstances. This study examines the spatiotemporal similarity of the Richardson relative dispersion in the Gulf of Mexico by reanalyzing the Lagrangian trajectory of the surface drifter provided by two famous field experiments, that is, the Grand Lagrangian Deployment and the Lagrangian Submesoscale Experiment. The experimental dispersion curve indicates a critical separation time. When above this critical time, the dispersion shows an asymptotic power law growth independent of the initial separation distance r 0 . Below it, the dispersion curve shows a strong spatiotemporal dependence with two spatiotemporal similarity regimes that can be identified for both experiments by looking at the isoline of the normalized dispersion curve. A new similarity variable is introduced to successfully collapse measured dispersion curves. However, the observed spatiotemporal similarity cannot be reproduced by the submesoscale preserved model. Thus, our results suggest that small-scale fluctuations play a crucial role in the relative dispersion of oceanic flows.

Introduction China’s marine cities have reached a critical juncture after 40 years of rapid development. In this new stage, where internal circulation is the main focus, there is a need to enhance the internal circulation capabilities of these cities and unleash their full economic potential. This paper aims to explore the positioning and improvement path of marine cities in China's internal circulation network, and fully unleash the development potential of marine cities. Methods Based on data from 284 prefecture-level cities in China, this paper constructs the social network of China's urban internal circulation with the help of the modified gravity model, and explores the conditional configuration of the improvement of the status of marine cities in internal circulation network by using the fuzzy-set qualitative comparative analysis (fsQCA) method. Results and discussion (1) The development level of marine cities' internal circulation can be categorized into three tiers, led by Shanghai. The development gap between the 14 marine cities has gradually widened over recent years. (2) Chinese marine cities can be divided into three groups in the topological structure of China's urban internal circulation network: core, periphery, and edge, with Shanghai being the core "bridge" in the network. The traditional advantages of some northern economically strong cities in the construction of the internal circulation network have gradually been lost, and many marine cities have seen their leadership and control over the internal circulation network significantly weakened. (3) No single factor is a necessary condition for achieving a high-level status of marine cities in the internal circulation network. (4) The four conditional variables of demand side, supply side, industrial linkage and inter-regional integration have two sufficient condition configurations to enhance the status of marine cities in internal circulation network. Among them, the "industry-regional integration"-dominated configuration with the core of unblocking the bottlenecks of the internal circulation is the main path.

The aim of this study is to provide new insights on the age and growth of H. dactylopterus in the north-western Ionian Sea (central Mediterranean) by using different data sets and comparing three different methods, one direct by otolith reading corroborated by two indirect methods, by means of back calculation and Length Frequency Distribution analysis (LFDa), in order to obtain robust data for use in analytical management models. A total of 1403 specimens of blackbelly rosefish were sampled from habitats explored on muddy bottoms in the depth range 106-721 m and 309 individuals caught in the cold-water coral habitat between 418 and 635 m in depth. The length-frequency distributions of blackbelly rosefish showed a polymodal pattern in both habitats explored, with medium-small individuals caught on muddy bottoms and larger ones in coral habitats and canyons. The maximum age observed in females was 13 years (315 mm TL), while in males it was 15 years (336 mm TL), and no significant difference was observed comparing age-length keys from otolith readings of females with the males. The analysis of the daily increments allowed us to validate the average length of the first year of age (approximately 90-100 mm LT) obtained from the three different methods used. No significant difference was highlighted comparing the average lengths of age class 1, calculated with the direct method and by counting the daily increments. The von Bertalanffy growth parameters were estimated for the sexes and for the whole population from otolith readings and for the entire population by LFD analysis and the back calculation method. The growth curves were comparable between the different methods and no significant difference was observed. The von Bertalanffy growth parameters estimated for the different methods were comparable (otolith readings L ∞ 494 mm, k=0.06 years ⁻¹ , t 0 =-3.00 years; back calculation method L ∞ 487 mm, k=0.06 years ⁻¹ , t 0 =-2.30 years; LFDa L ∞ 415 mm, k=0.07 years ⁻¹ , t 0 =-2.23 years), indicating a slow growth in accordance with what has already been observed in other areas of the Mediterranean.

Dredged sediments, which are mud suspensions with concentrations exceeding the gelling point, are utilised in reclamation and Building with Nature projects. Beyond the gelling point, flocs occupy space and begin to form a network structure. This study investigates the impact of initial conditions, specifically the concentration above the gelling point and the stress state, on the consolidation of dredged sediment. The sediment from Lake Markermeer in the Netherlands was studied, specifically in the context of the construction of the Marker Wadden wetland. Material parameters were determined using two distinct experimental methods: settling columns and Seepage Induced Consolidation (SIC) tests. The differences observed between the two sets of material parameters suggest that the stress history and plastic deformation during mixing may influence the results. These effects were analysed using a one-dimensional vertical (1DV) consolidation model. The computed profiles were then compared with the profiles measured using an Ultrasonic High Concentration Meter. An initial concentration of 558.1 g/l, achieved by remixing the equilibrium profile of a normally consolidated suspension, resulted in larger final densities and a lower sediment-water interface. Conversely, a concentration of 175.6 g/l, achieved by remixing consolidating dredged sediment, yielded the same equilibrium layer thickness and density profile as virgin consolidation, albeit after a longer consolidation time. These findings are particularly relevant for land reclamation and wetland construction projects, where the initial density may be high and the dredging process’s mixing may alter the stress state.

It has been known that the cross-sectional shape of a column oscillator significantly influences its vibrational characteristics and energy conversion capacity, and can alter the nature of flow-excited vibration (FIV). Whether the addition of appendages to oscillators with different cross-sectional shapes enhances energy conversion capacity remains uncertain. In this study, the vibration characteristics and energy capture capabilities of an elastically supported oscillator with a semicircular appendage, suitable for low-speed seafloor current environments, are investigated. Experiments were conducted at zero degrees incidence for Reynolds numbers ranging from 5.041 × 10³ to 7.562 × 10 ⁴ , resulting in turbulent wake conditions. The hydrodynamic properties of the oscillators were evaluated through statistical analysis, Proper Orthogonal Decomposition (POD), and vortex core identification of Particle Image Velocimetry (PIV) fields. The energy capture capability of the oscillator was assessed through statistical analysis of its vibration displacement, frequency, and amplitude. The study's results indicate that an oscillator with symmetric sharp attachments and without vortex reattachment is favorable for galloping with self-excitation. Under equivalent conditions, the Circular-T-shaped oscillator demonstrates superior energy conversion capacity compared to existing models, with the galloping branch being the most efficient for energy conversion; the peak efficiency is 24.5% (Ur = 14.5). This study provides some baseline data and optimization solutions for flow-induced motion power generation.

We investigated the distribution, C:N elemental ratio, and δ¹³C of suspended particulate carbon in the surface and upper 100 m of the water column during three seasons in areas of the Western Tropical North Atlantic influenced by the Amazon River Plume: the Spring high flow period (KN197 Cruise, May-June), the late Summer period of reduced flow (AT2104 cruise, July), and the low flow period in the Fall (MV1110 cruise, Sept-Oct). We used a habitat delineation method to examine spatial and temporal variability in our biogeochemical parameters. We found the highest biomass concentration ([PC]=259.7 µM), high C:N ratio (13.6), and the most negative δ¹³C (-26.8 ‰) in the area proximate to the river mouth during the late summer cruise. We measured elevated [PC] (64.5 µM), C:N ratios (14.1), and δ¹³C (max -15.7 ‰) in the plume core habitats during the peak flow season, reflecting the impact of both the outflow and in situ phytoplankton production. We found that the western margin of the plume had relatively higher biomass, C:N ratios, and organic matter more enriched in ¹³ C than the east margins. In our work area, oceanic waters had the lowest [PC] (1.3 µM), a C:N ratio higher than the Redfield ratio (6.6), and an average δ¹³C of -22 ‰. We explored the relationships between PC and Chla, and δ¹³C and C:N ratio to estimate the contribution of phytoplankton production and terrigenous sources to the suspended particulate carbon pool. We found terrestrial and detrital sources contributing more to the organic matter of the river mouth area. However, the contribution of phytoplankton and living sources dominate most of our study area in all seasons. Our findings emphasize the role of the Amazon River Plume in enhancing biomass and productivity of the WTNA and the biogeochemical dynamic of the carbon cycle.

Coral bleaching events have become more frequent in recent years due to the impact of widespread marine heatwaves. The Coral Reef Watch (CRW) program, part of the National Oceanic and Atmospheric Administration (NOAA), assesses bleaching risk by considering measures of daily coral heat stress (Hotspot, HS) and accumulated heat stress (Degree Heating Week, DHW). However, there is a mismatch between coral bleaching alerts through satellite monitoring and records of coral bleaching in the South China Sea (SCS) and its surrounding seas in the historical database. Through comparison with field records of bleaching events in the SCS, this study examined the optimization of the DHW under a fixed or variable HS threshold, evaluating the accuracy of coral bleaching monitoring through a range of evaluation indices, including the Peirce Skill Score (PSS) and the Area Under the Curve (AUC). Our results show that when the DHW index was calculated based on the current operational HS threshold (1°C), reducing the DHW threshold from 4°C to 1.86°C-weeks significantly improved PSS from 0.17 to 0.66, and AUC from 0.58 to 0.83. Further, by optimizing both HS and DHW, evaluation statistics were further improved, with the PSS increasing to 0.71 and the AUC increasing to 0.85. While both methods could significantly optimize the operational bleaching alert level for the SCS, the results suggest that optimization of both the HS and DHW thresholds is better than optimizing DHW alone. As marine heatwaves become more frequent, accurately predicting when and where coral bleaching is likely to occur will be critical to improving the estimation of regional coral stress due to climate change and for understanding coral reefs’ response to recurrent bleaching events.

The rich and special biodiversity in mountain rivers is experiencing a continuous decline due to the influence of climate change and anthropogenic factors. To explore the alterations in the distribution of aquatic biodiversity in mountain rivers in the context of cascade dam development, the environmental DNA (eDNA) metabarcoding technique was used to examine the aquatic biodiversity of the Wujiang River, a representative mountain river with an 11-stage cascade dam. In this study, a comprehensive analysis of aquatic organisms in the Wujiang River mainstem was conducted, and 17 phyla and 38 classes were detected in the 36 water samples. The most abundant group is the benthic organisms, and the least abundant group is the amphibians. The results of the diversity analysis showed a clear longitudinal distribution pattern of aquatic organisms along the altitudinal gradient, with higher richness of aquatic organism communities the further to the lower reaches. Meanwhile, RDA analysis revealed that altitude, dissolved oxygen, reservoir length, and reservoir construction time were the key environmental factors influencing the distribution of aquatic organisms in the Wujiang River mainstem. The findings of this research also showed the applicability of the eDNA method in detecting aquatic biodiversity.

Sea-crossing bridges face critical challenges due to scour, which can destabilize foundations. This study investigates the scour characteristics of the large-diameter main pier of the Haiwen Bridge, with a pile diameter of 4.3 meters. Seabed changes were monitored over 630 days using field tests and numerical simulations. The study analyzed the relationship between flow velocity and scour depth, revealing that the maximum recorded scour depth was 3.65 meters at the upstream side. A linear regression model, developed from 75 sets of field data, produced a formula to estimate maximum local scour depth. Validation against field measurements showed a strong correlation, with the calculated values deviating by less than 10% from observed data. The findings indicate that upstream scour pits were 1.5 times wider and deeper than those downstream, while a shallow triangular scour zone, extending 1.2 times the pile diameter, formed downstream. Recommendations for scour protection include hydrological considerations, particularly on the upstream side and areas lacking sediment sources.

Effectively assessing the basic genomic information of a species is fundamental for conducting molecular research and provides a foundation for constructing whole-genome maps. Hapalogenys analis is a temperate and tropical nearshore marine fish in China’s coastal waters, with significant economic value and high aquaculture potential. However, the genomic differences between male and female individuals of this species are not yet apparent. This study conducted whole-genome survey analyses on male and female H. analis to provide basic genomic information. According to K-mer analysis, the genome sizes of female and male fish were 436.24 Mb and 493.21 Mb. The heterozygosity rates were 0.58% for females and 0.23% for males. The proportion of repetitive sequences of female and male fish were 42.95% and 51.20%. The GC content of the genomes was 43.30% for female and 43.20% for male. The sizes of the assembled genomes were 589.18 Mb for female and 592.02 Mb for male, with N50 lengths of 3,135 bp and 3,041 bp, respectively. SSR screening results showed that 959,447 and 894,158 SSR sequences were detected in the genomes of female and male, respectively. The lengths of the assembled mitochondrial genome sequences were 19,755 bp for female and 19,754 bp for male, each containing 38 genes. Among these mitochondrial sequences, 13 protein-coding genes were identified, including 7 NADH dehydrogenase, 3 cytochrome c oxidase, 1 cytochrome b, and 2 ATP synthase genes. Both sequences contained 23 tRNA genes and 2 rRNA genes. This study provides a theoretical basis for constructing a high-quality whole genome of H. analis and valuable data for subsequent molecular breeding research.

The cosmetics industry is experiencing continuous growth and the search for dermoactive metabolites continues to increase, positioning natural marine products as an essential element in this market. The genus Sargassum, a cosmopolitan brown alga, stands out for its diversified arsenal of metabolites with biological properties of great interest for the cosmetic sector. This study presents an updated review of the dermocosmetic properties of 17 Sargassum species published between 2020 and 2024, emphasizing increasing interest in its antioxidant and photoprotective properties. Furthermore, the review highlights the crucial role of green extraction methodologies, such as ultrassom-assisted extraction (EAU), enzyme-assisted extraction (EAE) and microwave-assisted extraction (MAE). It is also provided a conceptual outline of the spectrometric analytical techniques used for characterization of extracts and identification of active composts, such as polysaccharides (alginate and fucoidane), phenolic composts (phlorotannins and phenylpropanóids) and terpenoids (diterpenoids, saponins and norisoprenóids). In addition to addressing bioprospecting and the potential of the biorefinery in the cosmetics sector, this review analyzes challenges related to quality control of raw materials, seasonal fluctuations of seaweed and regulations governing the collection and use of seaweed. To provide a detailed update on the dermocosmetic potential of these algae, the review aims to support future research and encourage bioprospection of this biomass as a sustainable and promising source for the development of new bioproducts.

The marine ecological civilization construction (MECC) plays an indispensable role in the development of ecological civilization in China. With the growth of the marine economy, threats to ecological environment have been increasing. From the standpoint of land-sea coordination, this study evaluates the MECC in China's coastal province and employs social network analysis to explore the spatial correlation network structure and radiation capacity. The results show that: (1) The MECC in China's coastal provinces has exhibited a general upward trend with occasional fluctuations. However, the subsystems exhibit disparate developmental trends, with the pressure subsystem exhibiting a slight decline. (2) While the MECC of all coastal provinces has increased, the MECC of China's coastal provinces exhibits considerable variation, with each facing different development challenges. (3) The spatial correlations of the MECC among coastal provinces have become increasingly pronounced, particularly in the regions surrounding Hangzhou Bay and Bohai Bay, while long-distance trans-regional correlations are relatively weaker. (4) There have been notable improvements in the MECC radiation capacity of all provinces, most prominently in Shanghai, Zhejiang, Jiangsu, and Shandong, which currently rank among the highest in the country. Conversely, the MECC radiation capacity of Liaoning, Hebei, Fujian, and Hainan remains relatively underdeveloped. The results indicate that while the MECC has developed, it still encounters obstacles pertaining to regional disparities, subsystem challenges, and spatial correlation development. The study concludes with a series of recommendations aimed at fostering sustainable development of the MECC in China's coastal regions.

The widespread use of polymers across various industries has led to significant microplastic pollution in marine environments, with millions of tons of microplastics being released annually. This study examines the contribution of coatings particles released from commercial ships, to marine microplastic pollution. Key sources of these microplastics include the weathering and abrasion of coatings during ship maintenance activities. Marine coatings, which are rich in polymers such as polyurethanes and epoxies, are released into the ocean through processes like normal wear and tear, damage, in-water cleaning, and removal of old paint layers. Our research indicates that the global shipping sector could be a substantial contributor to microplastic pollution, potentially releasing thousands of tons annually. Predictive modeling identifies bulk carriers as the largest contributors, followed by tankers, containerships, and cargo vessels. This study also finds that manual biofouling cleaning by divers generates more microplastics than cleaning using mechanized in-water cleaning (IWC) systems with debris capture. Mitigation strategies, such as alternative cleaning methods and improved waste capture and processing, are proposed, but their effectiveness remains uncertain due to implementation challenges. A multidisciplinary approach and coordinated global efforts are essential to develop effective strategies for reducing microplastic pollution from ship coatings and protecting marine ecosystems.

Introduction Predators, such as sharks, play important ecological roles in coastal ecosystems when abundant and these roles change over ontogeny. However, these shifts in ecological role are often not evaluated in light of feeding performance. Bite force is an ecologically relevant metric of feeding performance that has been associated with a species’ foraging niche, which may serve as a key factor that constrains prey selection both within and among sympatric species. Methods This study applies an interdisciplinary approach to discern the ecomechanical relationships of sympatric bull (Carcharhinus leucas), blacktip (Carcharhinus limbatus), and bonnethead sharks (Sphyrna tiburo) using feeding biomechanics and bulk stable isotopes (δ¹³C, δ¹⁵N). We sought to (1) estimate theoretical bite force and scaling patterns over ontogeny of each species, (2) quantify niche breadth and overlap among species, and (3) characterize the relationship between ecological niche shifts and changes in bite force over ontogeny. Results Importantly, we found that smaller conspecifics exhibited positive allometric scaling of bite force, whereas larger conspecifics exhibited isometric scaling. Associations between bite force and ontogenetic niche shifts in habitat and diet were found in bull and bonnethead sharks, but not in blacktip sharks. Additionally, isotopic niche breadth was greatest in generalist bull sharks, followed by specialist bonnethead and blacktip sharks. Discussion These findings highlight animal performance measures as critical drivers ofecological relationships both within and among species. Size-based differences in bite force scaling should be considered when evaluating feeding performance in other taxa, which may be an important determinant of ontogenetic dietary shifts.

The phenomenon of transforming natural marine space into proliferative capital holds global significance in modern modes of production. Under China’s socialist market economy, the property rights system and resource allocation methods have created a unique approach to the capitalization of marine space. Drawing on concepts related to the capitalization of space and land, this paper develops the idea of the capitalization of marine space. It is a process where the right to use the sea area is transferred by the rights holders through methods such as transfer, lease, or shares and is ultimately put into production as a means of production to realize the creation of capital value and surplus value. Using the mariculture industry on Guanglu Island in Changhai County as a case, this analysis delves into the process and mechanisms of the capitalization of marine space in China, the world’s leading mariculture nation, while considering the material agency of marine space. The research results show that: ① The specific realization process of marine space capitalization in the mariculture industry has gone through three stages: from natural marine space to marine space resources, from marine space resources to marine space assets, and the participation of marine space assets in creating value and surplus value. ② The material agency of marine space determines the feasibility of the capitalization of marine space and is also the decisive subject in shaping the specific practice of capitalization. The survival and profit needs of mariculture fishermen and enterprises drive the realization of the capitalization of marine space. China’s central and local governments participate in realizing the capitalization of marine space with the relevant institutional policies and norms aimed at economic development.

Mesoscale dynamics is essential to understanding the physical and biological processes of the coastal ocean regions due to its ability to modulate water properties. However, on the shelf, interactions between eddies, coastal currents, and topography involve complex processes whose observation, understanding, and accurate simulation still pose a major challenge. The purpose of our work is to quantify the mesoscale eddies in the northern Gulf of Guinea, off West Africa (10°W–10°E, 2°N–7°N), and their dynamical interaction with the near-surface ocean particularly in the coastal upwelling that occurs in summer between 2°W and 2°E. We used a regional NEMO model simulation at 1/36° resolution over the 2007–2017 period with daily outputs. A total of 38 cyclonic and 35 anticyclonic eddy trajectories were detected over the 2007–2017 period in July–August–September (JAS), with a mean radius along their trajectories of 95 km and 125 km, respectively. The mean lifetime for cyclones and anticyclones is approximately 1 month with an associated sea-level amplitude between 1 and 2 cm. We then focused on the JAS upwelling period of the year 2016 and found a 73 km radius cyclonic eddy east of Cape Three Points (Ghana) with a lifetime of 1 month which interacted with the coastal upwelling. Indeed, the quasi-stationary eddy dwelled within the coastal upwelling region from mid-July to mid-August 2016. A Lagrangian study shows that the eddy waters come from the coastal upwelling, then mix with warmer offshore waters, and later are transported eastward by the Guinea Current. Using a heat budget analysis, we show that this eddy–coastal upwelling interaction has an impact on sea surface temperature (SST) with a double effect: i) the eddy expands offshore the cold and salty waters (23°C and 35.6) of the coastal upwelling from 14 to 26 July; and ii) from 27 July until its dissipation, the eddy weakens this upwelling by an easterly inflow of warm offshore waters. This study highlights how the eddy–upwelling interaction can modulate the coastal upwelling in the northern Gulf of Guinea.