Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advance...Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advances within the field of estuarial,coastal,offshore,and deepwater engineering with particular reference to developments.The Journal is concerned with all engineering aspects involved in the exploration and utilization of ocean resources.Topics regularly covered include research,design and construction of structures(including wharfs,dikes,breakwaters,platforms,mooring systems,etc.),instrumentation/testing(physical model and numerical model),wave dynamics,sedimentation,structural/stress analysis,soil mechanics,and material research.展开更多
Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advance...Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advances within the field of estuarial,coastal,offshore,and deepwater engineering with particular reference to developments.The Journal is concerned with all engineering aspects involved in the exploration and utilization of ocean resources.Topics regularly covered include research,design and construction of structures(including wharfs,dikes,breakwaters,platforms,mooring systems,etc.),instrumentation/testing(physical model and numerical model),wave dynamics,sedimentation,structural/stress analysis,soil mechanics,and material research.展开更多
Spartina alterniflora invasions seriously threaten the structure and functions of coastal wetlands in China.In this study,the Suaeda salsa community in the Yellow River Estuary wetland was monitored using long-term La...Spartina alterniflora invasions seriously threaten the structure and functions of coastal wetlands in China.In this study,the Suaeda salsa community in the Yellow River Estuary wetland was monitored using long-term Landsat satellite images acquired from 1997 to 2020 to quantify the impact of changes in hydrological connectivity induced by S.alterniflora on neighboring vegetation com-munities.The results showed that S.alterniflora rapidly expanded in the estuary area at a rate of 4.91 km^(2)/yr from 2010 to 2020.At the same time,the hydrological connectivity of the area and the distribution of S.salsa changed significantly.Small tidal creeks dominated the S.alterniflora landscape.The number of tidal creeks increased significantly,but their average length decreased and they tended to develop in a horizontal tree-like pattern.Affected by the changes in hydrological connectivity due to the S.alterniflora invasion,the area of S.salsa decreased by 41.1%,and the degree of landscape fragmentation increased from 1997 to 2020.Variations in the Largest Patch Index(LPI)indicated that the S.alterniflora landscape had become the dominant landscape type in the Yellow River Estuary.The res-ults of standard deviation ellipse(SDE)and Pearson’s correlation analyses indicated that a well-developed hydrological connectivity could promote the maintenance of the S.salsa landscape.The degradation of most S.salsa communities is caused by the influence of S.alterniflora on the morphological characteristics of the hydrological connectivity of tidal creek systems.展开更多
Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impac...Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impact on marine biodiversity and human health.This study examined the occurrence,spatial distribution,physical and chemical properties,ecological risks,and probable sources of MPs in estuarine and coastal marine environments in the northeastern Bay of Bengal.The average concentration of MPs in surface water of the Karnaphuli estuary,the Meghna estuary,and the southeastern coastal region were 916.7±462.6 items/m^(3),462.9±324.5 items/m^(3),and 350.0±190.5 items/m^(3),respectively,varying from 105.0±324.5 items/m^(3)to 1640.0±462.6 items/m^(3).In the sediments of the Karnaphuli estuary,the Meghna estuary,and the southeast coast of Bangladesh,the average amount of MPs were 94.3±33.1 items/kg,157.6±89.0 items/kg,and 134.3±38.7 items/kg,with a range of 60±33.1 items/kg to 334.3±89.0 items/kg.Most observed MPs were fibers(60.0%in the water;56.0%in the sediments),followed by fragments and lines.Detected MPs were dominated by polypropylene(20.7%)in the water,and acrylic(15.4%)in the sediment,black colored(76.2%in the water,72.7%in the sediments),and 200-500μm sized(48%in the water,37%in the sediments).Pollution Risk Index(PRI)indicated significant pollution levels(from medium to very high)in estuarine and coastal areas.Multi-statistical analysis indicated land-based inputs(tourists,local waste,agriculture,and industry)dominated the studied regions.The study emphasized the potential impact of MPs pollution on aquatic ecosystems,emphasizing the need for effective management,mitigation methods,continuous surveillance,and thorough evaluation.展开更多
The spatial variability of mesozooplankton(MZ)community characteristics,with an emphasis on the predominant taxa,copepods,were evaluated between two distinct coastal water environments of Mangalore:the Netravati-Gurup...The spatial variability of mesozooplankton(MZ)community characteristics,with an emphasis on the predominant taxa,copepods,were evaluated between two distinct coastal water environments of Mangalore:the Netravati-Gurupura estuarine system(NGES)and the adjacent nearshore waters(<20 m depth)on the southwest coast of India during winter 2018.The nearshore waters were characterised by uniformly distributed hydrographic properties,particularly in terms of water column temperature,salinity and turbidity.This well-mixed water column likely stimulated increased phytoplankton chlorophyll a concentrations[av.(2.9±2.2)mg/m^(3)],which in turn supported higher MZ biomass[av.(0.4±0.15)mL/m^(3)]and abundance[av.(6889±3387)ind./m^(3)]in the nearshore waters.In contrast,the NGES exhibited highly variable hydrographic conditions,leading to inconsistent chlorophyll a[av.(3.2±3.7)mg/m^(3)],along with significantly lower MZ biomass[av.(0.1±0.2)mL/m^(3)]and abundance[av.(238±339)ind./m^(3)].The MZ community was dominated by herbivorous copepods(HCs),particularly Bestiolina similis,in the entire study region;however,the nearshore waters supported a more diverse taxon.The overall dominance of HCs,e.g.,B.similis and Pseudodiaptomous aurivillii,in the nearshore waters,indicates the presence of stable hydrographic conditions,especially consistently higher salinity and chlorophyll a level.In contrast,the unstable hydrographic conditions in the NGES,primarily reflected in the uneven salinity distributions,likely contributed to the reduced MZ biomass and abundance.The relative increase in the abundance of B.similis observed exclusively in the euhaline zones of the estuary highlights the significant influence of neritic waters.展开更多
Macrobenthos can serve as an indicator of hypoxia in the estuarine ecosystem.This comparative study surveyed macrobenthos from hypoxic and non-hypoxic areas of the Zhujiang(Pearl)River Estuary(PRE),and explores the ef...Macrobenthos can serve as an indicator of hypoxia in the estuarine ecosystem.This comparative study surveyed macrobenthos from hypoxic and non-hypoxic areas of the Zhujiang(Pearl)River Estuary(PRE),and explores the effects of environmental factor on the macrobenthos community structure.In July 2020,49 macrobenthos species were collected from the hypoxic area,contrasting with 91 species found in the non-hypoxic area.July 2021 recorded 51 species in the hypoxic area and 76 in the non-hypoxic area.Analysis of similarities(ANOSIM)and non-metric multidimentional scaling(NMDS)showed no significant difference in the macrobenthos community structure between the two areas.However,Polychaeta displays higher species richness,abundance,and biomass in the hypoxic zone,negatively correlating to dissolved oxygen(DO).Canonical correspondence analysis(CCA)also showed that the abundance of Polychaeta was negatively correlated with that of Crustacea.Interestingly,despite the differences in Polychaeta,macrobenthos community structure remains stable between hypoxic and non-hypoxic samples.This study suggests Polychaeta’s potential adaptation to hypoxic conditions in the PRE’s hypoxic area.Finally,Spearman correlation analysis showed that DO have a significant negative correlation with total phosphorus(TP),total nitrogen(TN)and total organic carbon(TOC)in the PRE,indicating that water eutrophication would exacerbate the occurrence of hypoxia.展开更多
Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic...Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire.展开更多
We investigated the concentrations,vertical distribution,and enrichment status of ten trace metal elements(Cr,Hg,Cu,Pb,Zn,Cd,As,Co,V,and Ni)in sediments of core D04 from the muddy area outside the Oujiang River Estuar...We investigated the concentrations,vertical distribution,and enrichment status of ten trace metal elements(Cr,Hg,Cu,Pb,Zn,Cd,As,Co,V,and Ni)in sediments of core D04 from the muddy area outside the Oujiang River Estuary.In addition to V,As,and Hg,the concentrations of Cr,Cu,Zn,Pb,Cd,Ni and Co were constrained by sediment grain size and organic matter.Al-though the concentrations of trace metals fluctuated during the 5.8–2.5 kyr BP period,overall variations remained relatively stable.However,during the 2.5–0 kyr BP period,the concentrations of Cd,Zn,Cu,Pb,Ni,Ni,and Cr showed an increasing trend within the fluctuations,ultimately reaching relatively high levels.The muddy area was lightly contaminated by heavy metals such as As,Hg,and Cu.The concentrations of Hg,As,and Cu have been continuously increasing since 2.5 kyr BP,indicating clear impacts from fre-quent human activities.展开更多
The flux of dissolved inorganic nitrogen(DIN),predominantly nitrate(NO_(3)^(-))and ammonium(NH_(4)^(+)),from land to coastal waters via rivers is commonly estimated simply by multiplying water flux with nitrogen conce...The flux of dissolved inorganic nitrogen(DIN),predominantly nitrate(NO_(3)^(-))and ammonium(NH_(4)^(+)),from land to coastal waters via rivers is commonly estimated simply by multiplying water flux with nitrogen concentration.Understanding DIN fluxes in gated estuaries is critical as these systems often serve as hotspots for nutrient transformations,influencing coastal water quality and ecosystem health.However,the subsequent interactions involving NO_(3)^(-)and NH_(4)^(+)adsorption or desorption on suspended sediments are often overlooked.To better understand the impact of these interactions on the overall NO_(3)^(-)and NH_(4)^(+)sorption or desorption and subsequently,the mobility and transport to the coastal zone,we conducted a series of NO_(3)^(-)and NH_(4)^(+)adsorption and desorption experiments.These experiments involved varying suspended sediment concentrations,particle sizes,salinities,and sea-salt ions to assess their potential effects.Results indicate that desorption of NO_(3)^(-)and NH_(4)^(+)from suspended sediments is more prominent than adsorption,with NH_(4)^(+)desorption being particularly significant.Notably,at low suspended particle concentrations and high salinity,NH_(4)^(+)desorption from sediments increased markedly,which further amplified in polyhaline conditions.This effect could result from ion pairing between NH_(4)^(+)and seawater anions,along with competition from seawater cations for sediment cation exchange sites,enhancing NH_(4)^(+)diffusion from estuarine sediments,and the elevated NH_(4)^(+)release could promote DIN transport to nearshore waters,especially in gated estuaries where sediment resuspension occurs.Given the critical role of NH_(4)^(+)in estuarine nitrogen cycling,ignoring these dynamics could lead to underestimations of DIN transport in river-estuary systems.Therefore,incorporating sediment dynamics into DIN flux estimations is crucial for accurately assessing nitrogen transport in gated estuaries.展开更多
Penaeus vannamei, known as the whiteleg shrimp, holds significant economic importance in aquaculture. The intensive culture of P. vannamei poses substantial environmental risks, particularly in fragile ecosystems like...Penaeus vannamei, known as the whiteleg shrimp, holds significant economic importance in aquaculture. The intensive culture of P. vannamei poses substantial environmental risks, particularly in fragile ecosystems like estuarine mangroves. Although there is a consensus on the pollution and harmful effects of microplastics(MPs), study on the pollution and potential risks posed by P. vannamei in estuary mangroves remains scarce. Therefore, the extent of microplastic pollution was evaluated and the correlation between the properties of MPs and the potential risks they pose to P. vannamei was examined.The average MP abundance in P. vannamei from Jiulong River estuary was determined to be 0.46±0.03 n/g in five different polymers, i.e., polypropylene(PP), polyethylene(PE), polystyrene(PS), polyethylene terephthalate(PET), and polyvinyl chloride resin(PVC). The total percentage of PS, PE, and PET polymers was the greatest(73.85%), where PET and PP(26.16%) were highly correlated in size and shape. Small MPs(1-200 μm) come in irregular particles, fragments, films, and large-sized MPs(200-1 000 μm) were mainly foam-shaped. The hazard risk level of MPs in P. vannamei from Jiulong River estuary reached grade Ⅲ, and the overall hazard risk index(H) value was 593.66. Among all samples,PVC polymer accounted for the lowest proportion(5.52%), but the H value was as high as 582.42, which contributed 98.11% to the overall hazard risk index. Regardless of global or Chinese, the microplastic pollution of P. vannamei in the estuary is at a moderate level. The protocol for MPs characteristics and correlation in seafood should be the basis for the risk assessment framework. Further studies are needed to evaluate how the exposure to MPs poses a risk for human health.展开更多
A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between ...A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between morphology and vegetation under similar tidal conditions.Our analysis of correlations and inferences revealed several significant trends in the SRD:(1)an overall expansion of land area and intertidal vegetation,with the most pronounced changes occurring in the eastern sector;(2)the predominance of river discharge influencing the southwestern and northern sectors,contrasted with the primary impact of storm surges in the eastern sector;and(3)three distinct causal relationships among estuarine morphology,vegetation,storm surges,and river discharge:a direct model where river discharge shapes estuarine morphology,a progressive model in which river discharge affects vegetation distribution,subsequently influencing estuarine morphology,and a hybrid model where storm surges directly impact vegetation and indirectly modify its distribution through changes in estuarine morphology.The stability of sediment supply and the role of intertidal vegetation are crucial for the continuous seaward advance,providing a vital foundation for the protection and development of estuarine deltas.展开更多
The turbidity maximum zone(TMZ)is a distinctive aquatic environment marked by consistently higher turbidity compared to upstream and downstream section.In the TMZ,physicochemical properties such as intense light limit...The turbidity maximum zone(TMZ)is a distinctive aquatic environment marked by consistently higher turbidity compared to upstream and downstream section.In the TMZ,physicochemical properties such as intense light limitation,abundant nutrients,and rapid salinity shifts play a crucial role in shaping phytoplankton dynamics.The Qiantang River estuary-Hangzhou Bay(QRE-HZB)is a macrotidal estuary system known for its exceptionally high suspended solids concentration.To investigate the impact of TMZ on the standing crop and size structure of phytoplankton in the QRE-HZB,we conducted three cruises in dry,wet,and dry-to-wet transition seasons during 2022-2023,by assessing parameters including size fractionated chlorophyll a(chl a),turbidity,Secchi depth,temperature,salinity,nutrients,and mesozooplankton.Results reveal significant variations in the TMZ and associated environmental factors in different periods,which markedly influenced the phytoplankton chl-a concentration,size structure,and cell activity(pheophytin/chl a).The chl-a concentration was high with micro-phytoplankton predominance in wet season,while nano-phytoplankton dominated in dry season.Within the TMZ,lower chl-a concentrations and pico-chl-a contributions,alongside higher pheophytin/chl-a and micro-chl-a contributions,were observed.The Spearman’s rank correlation and generalized additive model analyses indicated strong correlations of chl-a concentrations with turbidity,nutrients,and mesozooplankton.Redundancy analysis further revealed that salinity,nutrients,and turbidity significantly regulated variations in size structure.Phytoplankton mortality within the TMZ was primarily driven by high turbidity and salinity fluctuations,reflecting the vigorous resuspension and mixing of freshwater and seawater in the QRE-HZB.These findings highlight that the standing crop and size structure of phytoplankton were strongly regulated by the TMZ and associated physicochemical factors in the macrotidal QRE-HZB.展开更多
Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water sup...Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water supplement on tidal creek development and saltmarsh vegetation restoration,time series of high-resolution remote sensing images from2000 to 2021 were used to extract and analyze tidal creeks and saltmarsh vegetation in the Diaokou Estuary Reserve.The results are summarized as follows:(1)All tidal creek indices,except curvature,exhibited a significant linear increase with time,while curvature initially decreased and increased afterwards.The 5-year cumulative ecological water supplement volume was significantly positively correlated(R^(2)>0.7)with all tidal creek indices.(2)During the same period,most landscape pattern metrics of Phragmites australis increased,while those of Tamarix chinensis initially increased and then declined.Although the class area(CA)of Suaeda salsa increased with time,its perimeter-area fractal dimension(PAFRAC)and aggregation index(AI)fluctuated.(3)The CA of P.australis and S.salsa was significantly positively correlated with most tidal creek indices except curvature,while that of T.chinensis showed no significant correlation with any tidal creek index.Moreover,the AI and PAFRAC of P.australis were significantly positively correlated with fractal dimension,frequency/curvature of tidal creeks,respectively,while those of S.salsa and T.chinensis exhibited no significant correlation.In summary,the ecological water supplement project enhanced tidal creek development in coastal wetlands,promoting the restoration of P.australis and S.salsa,while having little impact on the restoration of T.chinensis.展开更多
Oyster farming provides substantial ecological and economic benefits but is often constrained by the challenges of selecting suitable sites in dynamic coastal environments.This study presents a tailored oyster suitabi...Oyster farming provides substantial ecological and economic benefits but is often constrained by the challenges of selecting suitable sites in dynamic coastal environments.This study presents a tailored oyster suitability index(OSI)for the Zhujiang(Pearl)River Estuary(PRE),developed using Landsat satellite imagery and in situ observations collected from 2013 to 2023.Key environmental parameters,including sea surface temperature(SST),salinity,turbidity,and chlorophyll-a(Chl-a)concentration,were integrated for OSI retrieval.Optimal algorithms for each parameter were identified through evaluation using field measurements,yielding high accuracy,as evidenced by strong determination coefficients(R^(2))and low root mean square error(RMSE):R^(2)=0.98,RMSE=0.74℃for SST;R^(2)=0.94,RMSE=0.50 for salinity;R^(2)=0.95,RMSE=1.21 mg/m^(3)for Chl-a;R^(2)=0.91,RMSE=1.48 NTU for turbidity.The OSI revealed pronounced seasonal and spatial variability,with the highest suitability observed during winter and the lowest during summer.Validation results demonstrated strong alignment between OSI predictions and existing oyster farming zones.These findings underscore the value of remote sensing for scalable,near-real-time aquaculture site assessments.The OSI framework provides a robust decision-support tool for optimizing oyster cultivation,promoting sustainable aquaculture development in dynamic estuarine systems such as the PRE and beyond.展开更多
Global warming underscores the urgent need to enhance carbon sinks to mitigate climate change,yet the role of coastal shellfish aquaculture area as either carbon sinks or sources remains unclear.In this study,we condu...Global warming underscores the urgent need to enhance carbon sinks to mitigate climate change,yet the role of coastal shellfish aquaculture area as either carbon sinks or sources remains unclear.In this study,we conducted high-resolution profiling observations of CO_(2)dynamics and net community production(NCP)in a mussel farm located in the Changjiang(Yangtze)River estuary(CRE)during early autumn.Results indicate that the partial pressure of CO_(2)(pCO_(2))in the water column was consistently higher than the atmospheric level,averaging 74.75±2.44 Pa,signaling that the mussel farm acted as a CO_(2)source.The average air-water CO_(2)exchange flux(FCO_(2))averaged-1.91±1.16 mmol/(m^(2)·h),and NCP in the water column(NCPCOL)averaged-6.66±12.81 mmol/(m^(2)·h),revealing a heterotrophic condition.A significant inverse correlation was found between NCPCOLand sea surface pCO_(2)with a lag time of approximately 3.31 h,highlighting the influence of biological activity in modulating CO_(2)dynamics.Physical processes such as freshwater inputs,vertical mixing,and wind patterns,also played a crucial role in shaping pCO_(2)variations.The study emphasizes the complexity of CO_(2)dynamics in costal aquaculture areas and the need for long-term,high-resolution monitoring to better understand their contribution to climate change mitigation.The high-resolution profiling system provided novel insights into the dynamics of NCP and CO_(2)fluxes,showing its potential as an advanced tool for studying aquaculture systems.Future research should focus on expanding the geographic and temporal scope of studies,combining observational and modeling approaches to better predict the responses of aquaculture systems to environmental changes.展开更多
High-dimensional data(a dataset with many features)were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea,North China.The twenty-five water quality parameters ...High-dimensional data(a dataset with many features)were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea,North China.The twenty-five water quality parameters analyzed were collected monthly from January 2021 to December 2021.Multivariate statistical techniques,such as the absolute principal component score-multiple linear regression model(APCS-MLR),correlation analysis,and analysis of variance were used to identify and quantify the potential sources or factors affecting water quality and to analyze the spatial-temporal variation in water quality.The water quality indices(WQIs),ranging from 67.96 to 70.67,showed that the water quality was at an intermediate level in the estuaries during both the flood and nonflood seasons.The concentrations of total phosphorus(TP),ammonia N(AN),and organic pollutants were greater in the Haihe River Basin than in the Liaohe River and Huanghe-Huaihe River Basins.The concentration of total nitrogen(TN)in the Haihe River Basin was lower than that in the Liaohe River and Huanghe-Huaihe River Basins.Heavy metal concentrations in the Liaohe River Basin were greater than those in the Haihe River and Huanghe-Huaihe River Basins.The annual mean concentrations of AN in the estuaries of the Haihe,Liaohe,and Huanghe(Yellow)rivers exhibited significant decreasing trends from 2013 to 2022,but no significant decreasing trends were found for permanganate index(COD_(Mn))or the TP.The concentrations of TN and AN were lower in the flood season than in the nonflood season,and the TP concentration was greater in the flood season than in the nonflood season.However,the concentrations of organic pollutants did not exhibit significant differences.Domestic sewage and industrial wastewater,substance exchange between air and water,nonpoint sources from rural and urban areas,and aquaculture wastewater were the major sources or factors responsible for water pollution in the estuaries.展开更多
The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the...The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary(PRE)region in winter 2021.The sum concentration of SOA tracers was 6.2–132.8 ng m^(−3),with SOAM and SOAI as the main components in both continental(scenarios A1 and A2)and marine air masses(scenario A3),as well as their combination(scenario A4).The highest and lowest levels of SOAM were observed in A1 and A3,respectively,which were mainly related to the variations in meteorological conditions,precursor concentrations,and the degree of photochemical processes.Higher MBTCA/HGA(3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid)ratios suggested a less significant contribution fromα-pinene to SOAM.The variations of SOAI in the different scenarios were associated with differences in relative humidity,particle acidity,and isoprene/NOx ratios.The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas,which was confirmed by the correlation among biogenic and anthropogenic precursors.The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes,with the highest concentrations in A1.A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25%to the total SOA at DWS,while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.展开更多
Mangrove forests are critical ecosystems for carbon sequestration,effectively capturing atmospheric carbon and permanently storing soil organic carbon(SOC)in coastal wetlands.Recent restoration and afforestation initi...Mangrove forests are critical ecosystems for carbon sequestration,effectively capturing atmospheric carbon and permanently storing soil organic carbon(SOC)in coastal wetlands.Recent restoration and afforestation initiatives have been undertaken to mitigate the rising atmospheric CO_(2) concentrations along tropical ocean coasts worldwide.The expansion of mangrove forests has garnered significant attention for elucidating their contributions to the permanent storage of carbon in both surface and subsoil layers.In this study,we investigated a recently expanding mangrove forest in the Beilun River Estuary of Guangxi Province,focusing on the abundance and sources of organic carbon(OC)in surface sediments.We also analyzed sediment grain size distribution,SOC,total nitrogen(TN)content,and stable carbon isotope composition(δ^(13)C).Additionally,we determined the molar ratio of SOC to nitrogen(C/N).The SOC content ranged from 0.25%to 6.58%,the C/N ratio varied from 9.85 to 17.73,δ^(13)C values spanned from-29.58‰to-24.93‰,andδ^(15)N values ranged from 3.10‰to 7.36‰.A strong correlation was observed between SOC and TN content.However,particle size did not significantly influence these relationships.In terms of SOC sources in the sediments,contributions from mangrove,terrestrial,and marine sources accounted for 37.1%to 99.5%,0.5%to 47.4%,and 0%to 17.6%,respectively.The findings of this study provide essential insights for evaluating and managing carbon sinks within the mangrove ecosystems of the Beibu Gulf region,contributing to more effective carbon management strategies in coastal areas.展开更多
The Changjiang River Estuary(CRE) and its offshore plumes host a diverse phytoplankton community;however, the spatiotemporal dynamics of these microorganisms and their environmental drivers remain poorly understood. T...The Changjiang River Estuary(CRE) and its offshore plumes host a diverse phytoplankton community;however, the spatiotemporal dynamics of these microorganisms and their environmental drivers remain poorly understood. This study aims to elucidate the spatiotemporal variations and environmental heterogeneity of phytoplankton communities in the CRE, as well as to understand the factors driving their assemblage. Utilizing ecological survey data collected from the CRE and adjacent waters during spring and summer from 2018 to 2020, we conducted a spatiotemporal analysis of phytoplankton β-diversity in the region. We decomposed β-diversity into species contributions to β-diversity(SCBD)and local contributions to β-diversity(LCBD) to examine spatial differences in phytoplankton diversity and the contributions of individual species within the community. Our findings reveal that spatial differences, primarily driven by water salinity and distance from the coastline, are key factors influencing the heterogeneity of phytoplankton community composition. Key species such as Skeletonema costatum, Melosira granulata, and M. granulata var.angustissima significantly affected β-diversity. Further, β-diversity decomposition reveals that community assembly is driven by interactive biogeochemical forces: salinity gradients shape spatial heterogeneity through runoff-seawater mixing, eutrophic conditions promote the dominance of nutrient-dependent taxa, and silica availability regulates diatom-to-flagellate succession. This study provides a methodological paradigm for analyzing phytoplankton community assembly mechanisms in estuaries, thereby offering scientific support for biogeography-based ecosystem management in the CRE.展开更多
The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from t...The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from the Yangtze River estuary to the upper Jinsha River,which extend to nearly 3 000 km.However,their migration behaviors remain relatively unknown.We analyzed the biological characteristics of 153 specimens of silver eels collected from the Jingjiang section of Yangtze River（31o30＇N,120o42＇E） between September and November,2008,and tested the sagittal Sr/Ca ratios of 27 specimens.Among the 153 specimens examined,85 were female and 68 were male,which translated to a female-male ratio of 1：0.8.The ages of the female specimens ranged from 3 to 7 a（average 5.52） with an average total length（TL） of（669±80） mm,average body weight（BW） of（555±229）g,average condition factor of 1.77±0.22,and average gonad somatic index（GSI） of 1.32±0.31.The ages of the males ranged from 3 to 5 a（average：4.38） with an average TL of（518±51） mm,average BW of（234±76） g,average condition factor of 1.62±0.18,and average GSI of 0.21±0.11.All biological parameters of females were significantly larger than those of the male specimens（P0.05）.According to the average Sr/Ca ratio（7.99±1.05） ×10-3 of the elver mark of sagitta,17 individuals（62.96%） were river eels and 10 individuals（37.04%） were estuarine eels.Of 16 females,13 individuals（81.25%） were river eels and 3 were estuarine eels,while of 11 males,36.36% were river eels and 63.64% were estuarine eels.The analysis on Sr/Ca ratios for every growth layer group（GLG） indicated there were no significant differences between second-age males and females.However,significant differences were observed between the third-age,fourth-age,and migration-age male and female specimens.This was likely related to the fact that second-age eels of both sexes stay in the same inhabitation waters;however,as they grow older,they move to different areas.展开更多
文摘Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advances within the field of estuarial,coastal,offshore,and deepwater engineering with particular reference to developments.The Journal is concerned with all engineering aspects involved in the exploration and utilization of ocean resources.Topics regularly covered include research,design and construction of structures(including wharfs,dikes,breakwaters,platforms,mooring systems,etc.),instrumentation/testing(physical model and numerical model),wave dynamics,sedimentation,structural/stress analysis,soil mechanics,and material research.
文摘Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advances within the field of estuarial,coastal,offshore,and deepwater engineering with particular reference to developments.The Journal is concerned with all engineering aspects involved in the exploration and utilization of ocean resources.Topics regularly covered include research,design and construction of structures(including wharfs,dikes,breakwaters,platforms,mooring systems,etc.),instrumentation/testing(physical model and numerical model),wave dynamics,sedimentation,structural/stress analysis,soil mechanics,and material research.
基金Under the auspices of Key Program of the National Natural Science Foundation of China(No.U2006215,U1806218)the National Key R&D Program of China(No.2017YFC0505902)。
文摘Spartina alterniflora invasions seriously threaten the structure and functions of coastal wetlands in China.In this study,the Suaeda salsa community in the Yellow River Estuary wetland was monitored using long-term Landsat satellite images acquired from 1997 to 2020 to quantify the impact of changes in hydrological connectivity induced by S.alterniflora on neighboring vegetation com-munities.The results showed that S.alterniflora rapidly expanded in the estuary area at a rate of 4.91 km^(2)/yr from 2010 to 2020.At the same time,the hydrological connectivity of the area and the distribution of S.salsa changed significantly.Small tidal creeks dominated the S.alterniflora landscape.The number of tidal creeks increased significantly,but their average length decreased and they tended to develop in a horizontal tree-like pattern.Affected by the changes in hydrological connectivity due to the S.alterniflora invasion,the area of S.salsa decreased by 41.1%,and the degree of landscape fragmentation increased from 1997 to 2020.Variations in the Largest Patch Index(LPI)indicated that the S.alterniflora landscape had become the dominant landscape type in the Yellow River Estuary.The res-ults of standard deviation ellipse(SDE)and Pearson’s correlation analyses indicated that a well-developed hydrological connectivity could promote the maintenance of the S.salsa landscape.The degradation of most S.salsa communities is caused by the influence of S.alterniflora on the morphological characteristics of the hydrological connectivity of tidal creek systems.
基金Supported by the National Natural Science Foundation of China(NSFC)Shared Voyage Project(Nos.41776088,41976018,42049911,U20A20103,U2005207)the Natural Science Key Foundation of Fujian Province,China(No.2020J01412103)+5 种基金the Hainan Province Science and Technology Special Fund(No.ZDYF2022SHFZ317)the Guangxi Talent and Innovation Base Project(No.2018AD19280)the Guangxi Funding Project(No.04024XM20N0006)the Beihai Science&Technology Project(Nos.201995037,202082031,202082022)the Natural Science Foundation of Xiamen City of China(No.502Z20227322)the China Scholarship Council(CSC Marine Scholarship)。
文摘Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impact on marine biodiversity and human health.This study examined the occurrence,spatial distribution,physical and chemical properties,ecological risks,and probable sources of MPs in estuarine and coastal marine environments in the northeastern Bay of Bengal.The average concentration of MPs in surface water of the Karnaphuli estuary,the Meghna estuary,and the southeastern coastal region were 916.7±462.6 items/m^(3),462.9±324.5 items/m^(3),and 350.0±190.5 items/m^(3),respectively,varying from 105.0±324.5 items/m^(3)to 1640.0±462.6 items/m^(3).In the sediments of the Karnaphuli estuary,the Meghna estuary,and the southeast coast of Bangladesh,the average amount of MPs were 94.3±33.1 items/kg,157.6±89.0 items/kg,and 134.3±38.7 items/kg,with a range of 60±33.1 items/kg to 334.3±89.0 items/kg.Most observed MPs were fibers(60.0%in the water;56.0%in the sediments),followed by fragments and lines.Detected MPs were dominated by polypropylene(20.7%)in the water,and acrylic(15.4%)in the sediment,black colored(76.2%in the water,72.7%in the sediments),and 200-500μm sized(48%in the water,37%in the sediments).Pollution Risk Index(PRI)indicated significant pollution levels(from medium to very high)in estuarine and coastal areas.Multi-statistical analysis indicated land-based inputs(tourists,local waste,agriculture,and industry)dominated the studied regions.The study emphasized the potential impact of MPs pollution on aquatic ecosystems,emphasizing the need for effective management,mitigation methods,continuous surveillance,and thorough evaluation.
基金the Port and Fisheries Division of the PWD and IWT Department, Government of Karnataka,for providing the research grant for executing the project(SSP 3243)
文摘The spatial variability of mesozooplankton(MZ)community characteristics,with an emphasis on the predominant taxa,copepods,were evaluated between two distinct coastal water environments of Mangalore:the Netravati-Gurupura estuarine system(NGES)and the adjacent nearshore waters(<20 m depth)on the southwest coast of India during winter 2018.The nearshore waters were characterised by uniformly distributed hydrographic properties,particularly in terms of water column temperature,salinity and turbidity.This well-mixed water column likely stimulated increased phytoplankton chlorophyll a concentrations[av.(2.9±2.2)mg/m^(3)],which in turn supported higher MZ biomass[av.(0.4±0.15)mL/m^(3)]and abundance[av.(6889±3387)ind./m^(3)]in the nearshore waters.In contrast,the NGES exhibited highly variable hydrographic conditions,leading to inconsistent chlorophyll a[av.(3.2±3.7)mg/m^(3)],along with significantly lower MZ biomass[av.(0.1±0.2)mL/m^(3)]and abundance[av.(238±339)ind./m^(3)].The MZ community was dominated by herbivorous copepods(HCs),particularly Bestiolina similis,in the entire study region;however,the nearshore waters supported a more diverse taxon.The overall dominance of HCs,e.g.,B.similis and Pseudodiaptomous aurivillii,in the nearshore waters,indicates the presence of stable hydrographic conditions,especially consistently higher salinity and chlorophyll a level.In contrast,the unstable hydrographic conditions in the NGES,primarily reflected in the uneven salinity distributions,likely contributed to the reduced MZ biomass and abundance.The relative increase in the abundance of B.similis observed exclusively in the euhaline zones of the estuary highlights the significant influence of neritic waters.
基金The Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.311021004the Biodiversity Assessment of Key Marine Habitat in China under contract Nos PM-zx555-202107-208 and PM-zx555-202106-195.
文摘Macrobenthos can serve as an indicator of hypoxia in the estuarine ecosystem.This comparative study surveyed macrobenthos from hypoxic and non-hypoxic areas of the Zhujiang(Pearl)River Estuary(PRE),and explores the effects of environmental factor on the macrobenthos community structure.In July 2020,49 macrobenthos species were collected from the hypoxic area,contrasting with 91 species found in the non-hypoxic area.July 2021 recorded 51 species in the hypoxic area and 76 in the non-hypoxic area.Analysis of similarities(ANOSIM)and non-metric multidimentional scaling(NMDS)showed no significant difference in the macrobenthos community structure between the two areas.However,Polychaeta displays higher species richness,abundance,and biomass in the hypoxic zone,negatively correlating to dissolved oxygen(DO).Canonical correspondence analysis(CCA)also showed that the abundance of Polychaeta was negatively correlated with that of Crustacea.Interestingly,despite the differences in Polychaeta,macrobenthos community structure remains stable between hypoxic and non-hypoxic samples.This study suggests Polychaeta’s potential adaptation to hypoxic conditions in the PRE’s hypoxic area.Finally,Spearman correlation analysis showed that DO have a significant negative correlation with total phosphorus(TP),total nitrogen(TN)and total organic carbon(TOC)in the PRE,indicating that water eutrophication would exacerbate the occurrence of hypoxia.
文摘Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire.
基金funded by National Natural Science Foundation of China(No.41706074)Natural Science Foundation of Shandong Province(No.ZR2022 MD114)Geological Environment Investigation and Monitoring of the Coastal Zone in the Yangtze River Estuary(No.DD20242714).
文摘We investigated the concentrations,vertical distribution,and enrichment status of ten trace metal elements(Cr,Hg,Cu,Pb,Zn,Cd,As,Co,V,and Ni)in sediments of core D04 from the muddy area outside the Oujiang River Estuary.In addition to V,As,and Hg,the concentrations of Cr,Cu,Zn,Pb,Cd,Ni and Co were constrained by sediment grain size and organic matter.Al-though the concentrations of trace metals fluctuated during the 5.8–2.5 kyr BP period,overall variations remained relatively stable.However,during the 2.5–0 kyr BP period,the concentrations of Cd,Zn,Cu,Pb,Ni,Ni,and Cr showed an increasing trend within the fluctuations,ultimately reaching relatively high levels.The muddy area was lightly contaminated by heavy metals such as As,Hg,and Cu.The concentrations of Hg,As,and Cu have been continuously increasing since 2.5 kyr BP,indicating clear impacts from fre-quent human activities.
基金Supported by the Tianjin Key R&D Program(No.21YFSNSN00220)。
文摘The flux of dissolved inorganic nitrogen(DIN),predominantly nitrate(NO_(3)^(-))and ammonium(NH_(4)^(+)),from land to coastal waters via rivers is commonly estimated simply by multiplying water flux with nitrogen concentration.Understanding DIN fluxes in gated estuaries is critical as these systems often serve as hotspots for nutrient transformations,influencing coastal water quality and ecosystem health.However,the subsequent interactions involving NO_(3)^(-)and NH_(4)^(+)adsorption or desorption on suspended sediments are often overlooked.To better understand the impact of these interactions on the overall NO_(3)^(-)and NH_(4)^(+)sorption or desorption and subsequently,the mobility and transport to the coastal zone,we conducted a series of NO_(3)^(-)and NH_(4)^(+)adsorption and desorption experiments.These experiments involved varying suspended sediment concentrations,particle sizes,salinities,and sea-salt ions to assess their potential effects.Results indicate that desorption of NO_(3)^(-)and NH_(4)^(+)from suspended sediments is more prominent than adsorption,with NH_(4)^(+)desorption being particularly significant.Notably,at low suspended particle concentrations and high salinity,NH_(4)^(+)desorption from sediments increased markedly,which further amplified in polyhaline conditions.This effect could result from ion pairing between NH_(4)^(+)and seawater anions,along with competition from seawater cations for sediment cation exchange sites,enhancing NH_(4)^(+)diffusion from estuarine sediments,and the elevated NH_(4)^(+)release could promote DIN transport to nearshore waters,especially in gated estuaries where sediment resuspension occurs.Given the critical role of NH_(4)^(+)in estuarine nitrogen cycling,ignoring these dynamics could lead to underestimations of DIN transport in river-estuary systems.Therefore,incorporating sediment dynamics into DIN flux estimations is crucial for accurately assessing nitrogen transport in gated estuaries.
基金Supported by the Natural Science Foundation of Xiamen (No. 3502Z20227322)the Natural Science Key Foundation of Fujian Province (No. 2020J02002)+1 种基金the Social Science Foundation of Fujian Province (No. FJ2024BF047)the Financial Research Projects of Fujian Province (No. 2024-48)。
文摘Penaeus vannamei, known as the whiteleg shrimp, holds significant economic importance in aquaculture. The intensive culture of P. vannamei poses substantial environmental risks, particularly in fragile ecosystems like estuarine mangroves. Although there is a consensus on the pollution and harmful effects of microplastics(MPs), study on the pollution and potential risks posed by P. vannamei in estuary mangroves remains scarce. Therefore, the extent of microplastic pollution was evaluated and the correlation between the properties of MPs and the potential risks they pose to P. vannamei was examined.The average MP abundance in P. vannamei from Jiulong River estuary was determined to be 0.46±0.03 n/g in five different polymers, i.e., polypropylene(PP), polyethylene(PE), polystyrene(PS), polyethylene terephthalate(PET), and polyvinyl chloride resin(PVC). The total percentage of PS, PE, and PET polymers was the greatest(73.85%), where PET and PP(26.16%) were highly correlated in size and shape. Small MPs(1-200 μm) come in irregular particles, fragments, films, and large-sized MPs(200-1 000 μm) were mainly foam-shaped. The hazard risk level of MPs in P. vannamei from Jiulong River estuary reached grade Ⅲ, and the overall hazard risk index(H) value was 593.66. Among all samples,PVC polymer accounted for the lowest proportion(5.52%), but the H value was as high as 582.42, which contributed 98.11% to the overall hazard risk index. Regardless of global or Chinese, the microplastic pollution of P. vannamei in the estuary is at a moderate level. The protocol for MPs characteristics and correlation in seafood should be the basis for the risk assessment framework. Further studies are needed to evaluate how the exposure to MPs poses a risk for human health.
基金National Natural Science Foundation of China,No.41906148,No.42271086Rejuvenating Yunnan Talents Support Plan Young Talent Program,No.XDYC-QNRC-2023-0322。
文摘A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between morphology and vegetation under similar tidal conditions.Our analysis of correlations and inferences revealed several significant trends in the SRD:(1)an overall expansion of land area and intertidal vegetation,with the most pronounced changes occurring in the eastern sector;(2)the predominance of river discharge influencing the southwestern and northern sectors,contrasted with the primary impact of storm surges in the eastern sector;and(3)three distinct causal relationships among estuarine morphology,vegetation,storm surges,and river discharge:a direct model where river discharge shapes estuarine morphology,a progressive model in which river discharge affects vegetation distribution,subsequently influencing estuarine morphology,and a hybrid model where storm surges directly impact vegetation and indirectly modify its distribution through changes in estuarine morphology.The stability of sediment supply and the role of intertidal vegetation are crucial for the continuous seaward advance,providing a vital foundation for the protection and development of estuarine deltas.
基金Supported by the National Key Research and Development Program of China(No.2021 YFC 3101702)the Key R&D Program of Zhejiang(No.2022 C 03044)+2 种基金the Scientific Research Fund of the Second Institute of Oceanography,MNR(No.JG 1521)the Project of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography(No.SOEDZZ 2202)the National Program on Global Change and Air-Sea Interaction(Phase Ⅱ)-Hypoxia and Acidification Monitoring and Warning Project in the Changjiang River estuary,and Long-term Observation and Research Plan in the Changjiang River estuary and Adjacent East China Sea(LORCE)Project(No.SZ 2001)。
文摘The turbidity maximum zone(TMZ)is a distinctive aquatic environment marked by consistently higher turbidity compared to upstream and downstream section.In the TMZ,physicochemical properties such as intense light limitation,abundant nutrients,and rapid salinity shifts play a crucial role in shaping phytoplankton dynamics.The Qiantang River estuary-Hangzhou Bay(QRE-HZB)is a macrotidal estuary system known for its exceptionally high suspended solids concentration.To investigate the impact of TMZ on the standing crop and size structure of phytoplankton in the QRE-HZB,we conducted three cruises in dry,wet,and dry-to-wet transition seasons during 2022-2023,by assessing parameters including size fractionated chlorophyll a(chl a),turbidity,Secchi depth,temperature,salinity,nutrients,and mesozooplankton.Results reveal significant variations in the TMZ and associated environmental factors in different periods,which markedly influenced the phytoplankton chl-a concentration,size structure,and cell activity(pheophytin/chl a).The chl-a concentration was high with micro-phytoplankton predominance in wet season,while nano-phytoplankton dominated in dry season.Within the TMZ,lower chl-a concentrations and pico-chl-a contributions,alongside higher pheophytin/chl-a and micro-chl-a contributions,were observed.The Spearman’s rank correlation and generalized additive model analyses indicated strong correlations of chl-a concentrations with turbidity,nutrients,and mesozooplankton.Redundancy analysis further revealed that salinity,nutrients,and turbidity significantly regulated variations in size structure.Phytoplankton mortality within the TMZ was primarily driven by high turbidity and salinity fluctuations,reflecting the vigorous resuspension and mixing of freshwater and seawater in the QRE-HZB.These findings highlight that the standing crop and size structure of phytoplankton were strongly regulated by the TMZ and associated physicochemical factors in the macrotidal QRE-HZB.
基金National Key Research and Development Program of China,No.2022YFC3204302China National Admin-istration of Coal Geology,No.ZMKJ-2021-ZX04。
文摘Ecological water supplement projects have been implemented in many coastal wetlands,influencing saltmarsh vegetation restoration by altering tidal creek development.To clarify the effectiveness of ecological water supplement on tidal creek development and saltmarsh vegetation restoration,time series of high-resolution remote sensing images from2000 to 2021 were used to extract and analyze tidal creeks and saltmarsh vegetation in the Diaokou Estuary Reserve.The results are summarized as follows:(1)All tidal creek indices,except curvature,exhibited a significant linear increase with time,while curvature initially decreased and increased afterwards.The 5-year cumulative ecological water supplement volume was significantly positively correlated(R^(2)>0.7)with all tidal creek indices.(2)During the same period,most landscape pattern metrics of Phragmites australis increased,while those of Tamarix chinensis initially increased and then declined.Although the class area(CA)of Suaeda salsa increased with time,its perimeter-area fractal dimension(PAFRAC)and aggregation index(AI)fluctuated.(3)The CA of P.australis and S.salsa was significantly positively correlated with most tidal creek indices except curvature,while that of T.chinensis showed no significant correlation with any tidal creek index.Moreover,the AI and PAFRAC of P.australis were significantly positively correlated with fractal dimension,frequency/curvature of tidal creeks,respectively,while those of S.salsa and T.chinensis exhibited no significant correlation.In summary,the ecological water supplement project enhanced tidal creek development in coastal wetlands,promoting the restoration of P.australis and S.salsa,while having little impact on the restoration of T.chinensis.
基金The Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.SML2021SP308the National Natural Science Foundation of China under contract Nos 42176173 and 42476268+1 种基金the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.311020004Guangdong Geographical Science Data Center under contract No.2021B1212100003.
文摘Oyster farming provides substantial ecological and economic benefits but is often constrained by the challenges of selecting suitable sites in dynamic coastal environments.This study presents a tailored oyster suitability index(OSI)for the Zhujiang(Pearl)River Estuary(PRE),developed using Landsat satellite imagery and in situ observations collected from 2013 to 2023.Key environmental parameters,including sea surface temperature(SST),salinity,turbidity,and chlorophyll-a(Chl-a)concentration,were integrated for OSI retrieval.Optimal algorithms for each parameter were identified through evaluation using field measurements,yielding high accuracy,as evidenced by strong determination coefficients(R^(2))and low root mean square error(RMSE):R^(2)=0.98,RMSE=0.74℃for SST;R^(2)=0.94,RMSE=0.50 for salinity;R^(2)=0.95,RMSE=1.21 mg/m^(3)for Chl-a;R^(2)=0.91,RMSE=1.48 NTU for turbidity.The OSI revealed pronounced seasonal and spatial variability,with the highest suitability observed during winter and the lowest during summer.Validation results demonstrated strong alignment between OSI predictions and existing oyster farming zones.These findings underscore the value of remote sensing for scalable,near-real-time aquaculture site assessments.The OSI framework provides a robust decision-support tool for optimizing oyster cultivation,promoting sustainable aquaculture development in dynamic estuarine systems such as the PRE and beyond.
基金Supported by the National Natural Science Foundation of China(Nos.U23A2033,41976154)the Key R&D Program of Zhejiang Province,China(No.2023C03011)+2 种基金the Key R&D Program of Guangxi,China(No.Guike AB22080099)the Science Foundation of Donghai Laboratory(No.DH-2022KF0205)the Bureau of Science and Technology of Zhoushan(No.2022C81006)。
文摘Global warming underscores the urgent need to enhance carbon sinks to mitigate climate change,yet the role of coastal shellfish aquaculture area as either carbon sinks or sources remains unclear.In this study,we conducted high-resolution profiling observations of CO_(2)dynamics and net community production(NCP)in a mussel farm located in the Changjiang(Yangtze)River estuary(CRE)during early autumn.Results indicate that the partial pressure of CO_(2)(pCO_(2))in the water column was consistently higher than the atmospheric level,averaging 74.75±2.44 Pa,signaling that the mussel farm acted as a CO_(2)source.The average air-water CO_(2)exchange flux(FCO_(2))averaged-1.91±1.16 mmol/(m^(2)·h),and NCP in the water column(NCPCOL)averaged-6.66±12.81 mmol/(m^(2)·h),revealing a heterotrophic condition.A significant inverse correlation was found between NCPCOLand sea surface pCO_(2)with a lag time of approximately 3.31 h,highlighting the influence of biological activity in modulating CO_(2)dynamics.Physical processes such as freshwater inputs,vertical mixing,and wind patterns,also played a crucial role in shaping pCO_(2)variations.The study emphasizes the complexity of CO_(2)dynamics in costal aquaculture areas and the need for long-term,high-resolution monitoring to better understand their contribution to climate change mitigation.The high-resolution profiling system provided novel insights into the dynamics of NCP and CO_(2)fluxes,showing its potential as an advanced tool for studying aquaculture systems.Future research should focus on expanding the geographic and temporal scope of studies,combining observational and modeling approaches to better predict the responses of aquaculture systems to environmental changes.
基金Supported by the National Natural Science Foundation of China(No.41571479)。
文摘High-dimensional data(a dataset with many features)were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea,North China.The twenty-five water quality parameters analyzed were collected monthly from January 2021 to December 2021.Multivariate statistical techniques,such as the absolute principal component score-multiple linear regression model(APCS-MLR),correlation analysis,and analysis of variance were used to identify and quantify the potential sources or factors affecting water quality and to analyze the spatial-temporal variation in water quality.The water quality indices(WQIs),ranging from 67.96 to 70.67,showed that the water quality was at an intermediate level in the estuaries during both the flood and nonflood seasons.The concentrations of total phosphorus(TP),ammonia N(AN),and organic pollutants were greater in the Haihe River Basin than in the Liaohe River and Huanghe-Huaihe River Basins.The concentration of total nitrogen(TN)in the Haihe River Basin was lower than that in the Liaohe River and Huanghe-Huaihe River Basins.Heavy metal concentrations in the Liaohe River Basin were greater than those in the Haihe River and Huanghe-Huaihe River Basins.The annual mean concentrations of AN in the estuaries of the Haihe,Liaohe,and Huanghe(Yellow)rivers exhibited significant decreasing trends from 2013 to 2022,but no significant decreasing trends were found for permanganate index(COD_(Mn))or the TP.The concentrations of TN and AN were lower in the flood season than in the nonflood season,and the TP concentration was greater in the flood season than in the nonflood season.However,the concentrations of organic pollutants did not exhibit significant differences.Domestic sewage and industrial wastewater,substance exchange between air and water,nonpoint sources from rural and urban areas,and aquaculture wastewater were the major sources or factors responsible for water pollution in the estuaries.
基金supported by the State Key Program of the National Natural Science Foundation of China(Grant Nos.42230701,91644215)the National Natural ScienceFoundation of China(Grant Nos.42122062 and 42307137)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010852)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.23hytd002)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2023SP218)L.M.acknowledges the Zhuhai Science and Technology Plan Project(Grant No.ZH22036201210115PWC).
文摘The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary(PRE)region in winter 2021.The sum concentration of SOA tracers was 6.2–132.8 ng m^(−3),with SOAM and SOAI as the main components in both continental(scenarios A1 and A2)and marine air masses(scenario A3),as well as their combination(scenario A4).The highest and lowest levels of SOAM were observed in A1 and A3,respectively,which were mainly related to the variations in meteorological conditions,precursor concentrations,and the degree of photochemical processes.Higher MBTCA/HGA(3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid)ratios suggested a less significant contribution fromα-pinene to SOAM.The variations of SOAI in the different scenarios were associated with differences in relative humidity,particle acidity,and isoprene/NOx ratios.The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas,which was confirmed by the correlation among biogenic and anthropogenic precursors.The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes,with the highest concentrations in A1.A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25%to the total SOA at DWS,while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.
基金The National Natural Science Foundation of China under contract No.42476043the Guangxi Key Research and Development Project under contract No.AB21076016+2 种基金the Scientific Research and Technology Development Project of Qinzhou under contract No.202116623the Natural Science Foundation of Guangxi under contract No.2021GXNSFAA075013the China College Students’Innovation and Entrepreneurship Training Program Project under contract No.S202411607002。
文摘Mangrove forests are critical ecosystems for carbon sequestration,effectively capturing atmospheric carbon and permanently storing soil organic carbon(SOC)in coastal wetlands.Recent restoration and afforestation initiatives have been undertaken to mitigate the rising atmospheric CO_(2) concentrations along tropical ocean coasts worldwide.The expansion of mangrove forests has garnered significant attention for elucidating their contributions to the permanent storage of carbon in both surface and subsoil layers.In this study,we investigated a recently expanding mangrove forest in the Beilun River Estuary of Guangxi Province,focusing on the abundance and sources of organic carbon(OC)in surface sediments.We also analyzed sediment grain size distribution,SOC,total nitrogen(TN)content,and stable carbon isotope composition(δ^(13)C).Additionally,we determined the molar ratio of SOC to nitrogen(C/N).The SOC content ranged from 0.25%to 6.58%,the C/N ratio varied from 9.85 to 17.73,δ^(13)C values spanned from-29.58‰to-24.93‰,andδ^(15)N values ranged from 3.10‰to 7.36‰.A strong correlation was observed between SOC and TN content.However,particle size did not significantly influence these relationships.In terms of SOC sources in the sediments,contributions from mangrove,terrestrial,and marine sources accounted for 37.1%to 99.5%,0.5%to 47.4%,and 0%to 17.6%,respectively.The findings of this study provide essential insights for evaluating and managing carbon sinks within the mangrove ecosystems of the Beibu Gulf region,contributing to more effective carbon management strategies in coastal areas.
基金The program of opening ceremony to select the best candidates of the Key Laboratory of Marine Ecological Monitoring and Restoration Technologies,MNR under contract No. MEMRT2024JBGS01。
文摘The Changjiang River Estuary(CRE) and its offshore plumes host a diverse phytoplankton community;however, the spatiotemporal dynamics of these microorganisms and their environmental drivers remain poorly understood. This study aims to elucidate the spatiotemporal variations and environmental heterogeneity of phytoplankton communities in the CRE, as well as to understand the factors driving their assemblage. Utilizing ecological survey data collected from the CRE and adjacent waters during spring and summer from 2018 to 2020, we conducted a spatiotemporal analysis of phytoplankton β-diversity in the region. We decomposed β-diversity into species contributions to β-diversity(SCBD)and local contributions to β-diversity(LCBD) to examine spatial differences in phytoplankton diversity and the contributions of individual species within the community. Our findings reveal that spatial differences, primarily driven by water salinity and distance from the coastline, are key factors influencing the heterogeneity of phytoplankton community composition. Key species such as Skeletonema costatum, Melosira granulata, and M. granulata var.angustissima significantly affected β-diversity. Further, β-diversity decomposition reveals that community assembly is driven by interactive biogeochemical forces: salinity gradients shape spatial heterogeneity through runoff-seawater mixing, eutrophic conditions promote the dominance of nutrient-dependent taxa, and silica availability regulates diatom-to-flagellate succession. This study provides a methodological paradigm for analyzing phytoplankton community assembly mechanisms in estuaries, thereby offering scientific support for biogeography-based ecosystem management in the CRE.
基金supported by the Chinese National Science Foundation under the Grant(30771650)the Key Programs of Science and Technology Commission Foundation of Shanghai(08391910200)+3 种基金Special Fund for Agroscientific Research in the Public Interest(201203065)Research Fund for the Doctoral Program of Higher Education of China(20070264001)E-class Programs of Shanghai Municipal Education Commission(E03009)the Key Subject Construction of Shanghai(S30701)
文摘The Yangtze River estuary is the main production area of Anguilla japonica in China,as well as the only existing fishery area for adult eels.Japanese eels are distributed in the main rivers and many tributaries from the Yangtze River estuary to the upper Jinsha River,which extend to nearly 3 000 km.However,their migration behaviors remain relatively unknown.We analyzed the biological characteristics of 153 specimens of silver eels collected from the Jingjiang section of Yangtze River（31o30＇N,120o42＇E） between September and November,2008,and tested the sagittal Sr/Ca ratios of 27 specimens.Among the 153 specimens examined,85 were female and 68 were male,which translated to a female-male ratio of 1：0.8.The ages of the female specimens ranged from 3 to 7 a（average 5.52） with an average total length（TL） of（669±80） mm,average body weight（BW） of（555±229）g,average condition factor of 1.77±0.22,and average gonad somatic index（GSI） of 1.32±0.31.The ages of the males ranged from 3 to 5 a（average：4.38） with an average TL of（518±51） mm,average BW of（234±76） g,average condition factor of 1.62±0.18,and average GSI of 0.21±0.11.All biological parameters of females were significantly larger than those of the male specimens（P0.05）.According to the average Sr/Ca ratio（7.99±1.05） ×10-3 of the elver mark of sagitta,17 individuals（62.96%） were river eels and 10 individuals（37.04%） were estuarine eels.Of 16 females,13 individuals（81.25%） were river eels and 3 were estuarine eels,while of 11 males,36.36% were river eels and 63.64% were estuarine eels.The analysis on Sr/Ca ratios for every growth layer group（GLG） indicated there were no significant differences between second-age males and females.However,significant differences were observed between the third-age,fourth-age,and migration-age male and female specimens.This was likely related to the fact that second-age eels of both sexes stay in the same inhabitation waters;however,as they grow older,they move to different areas.
