Globally,various types of pollution affect coastal waters as a result of human activities.Bioaugmentation and biostimulation are effective methods for treating water pollution.However,few studies have explored the res...Globally,various types of pollution affect coastal waters as a result of human activities.Bioaugmentation and biostimulation are effective methods for treating water pollution.However,few studies have explored the response of coastal prokaryotic and eukaryotic communities to bioaugmentation and biostimulation.Here,a 28-day outdoor mesocosm experiment with two treatments(bioaugmentation-A and combined treatment of bioaugmentation and biostimulation-AS)and a control(untreated-C)were carried out.The experiment was conducted in Meishan Bay to explore the composition,dynamics,and co-occurrence patterns of prokaryotic and eukaryotic communities in response to the A and AS using 16S rRNA and 18S rRNA gene amplicon sequencing.After treatment,Gammaproteobacteria and Epsilonproteobacteria were significantly increased in group AS compared to group C,while Flavobacteriia and Saprospirae were significantly reduced.Dinoflagellata was significantly reduced in AS compared to C,while Chrysophyta was significantly reduced in both AS and A.Compared to C,the principal response curve analyses of the prokaryotic and eukaryotic communities both showed an increasing trend followed by a decreasing trend for AS.Furthermore,the trends of prokaryotic and eukaryotic communities in group A were similar to those in group AS compared with group C,but AS changed them more than A did.According to the species weight table on principal response curves,a significant increase was observed in beneficial bacteria in prokaryotic communities,such as Rhodobacterales and Oceanospirillales,along with a decrease in autotrophs in eukaryotic communities,such as Chrysophyta and Diatom.Topological properties of network analysis reveal that A and AS complicate the interactions between the prokaryotic and eukaryotic communities.Overall,these findings expand our understanding of the response pattern of the bioaugmentation and biostimulation on coastal prokaryotic and eukaryotic communities.展开更多
The first record of abnormal body coloration in Sebastes koreanus Kim and Lee,1994,from the Yellow Sea of China,was documented based on morphological characteristics and DNA barcoding.The two rockfish specimens were c...The first record of abnormal body coloration in Sebastes koreanus Kim and Lee,1994,from the Yellow Sea of China,was documented based on morphological characteristics and DNA barcoding.The two rockfish specimens were collected from the coastal waters of Qingdao,China,and the whole body and all fins of them were red.Of the two red-colored rockfish,there were tiny deep red spots on each fin,2 red radial stripes behind and below the eyes and 1 large deep red blotch on the opercula,while the similar stripe and spot patterns are also present in the S.koreanus specimens with normal body coloration.The countable characteristics of the two specimens are in the range of the morphometry of S.koreanus.To further clarify the species identity and taxonomic status of the two specimens,DNA barcode analysis was carried out.The genetic distance between the red-colored rockfish and S.koreanus was 0,and the minimum net genetic distances between the red-colored rockfish and other Sebastes species except for S.koreanus were 3.0%,which exceeds the threshold of species delimitation.The phylogenetic analysis showed that the DNA barcoding sequences of the two red-colored rockfish clustered with the S.koreanus sequences.The above results of DNA barcode analysis also support that the two red-colored rockfish could be identified as the species of S.koreanus.The mechanism of color variation in S.koreanus is desirable for further research and the species could be an ideal model to study the color-driven speciation of the rockfishes.展开更多
Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary productivity.The satellite observations show that the norther...Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary productivity.The satellite observations show that the northern Arafura Sea(NAS),especially in the coastal region,features high chlorophyll-a(chl-a)concentrations,implying a strong coastal upwelling.However,coastal upwelling in the NAS has not received much attention.Based on a semi-automatic image processing technology,the seasonal and interannual variability of coastal upwelling in the NAS are investigated in this study using satellite-observed sea surface temperature(SST)and wind data.The results suggest that there are seasonal coastal upwelling events in the NAS modulated by upwelling-favorable southeast monsoon(SEM).The annual mean days,mean area,and annual mean intensity of coastal upwelling events during the SEM season are 92 days,6514 km^(2),and-5.31×10^(5),respectively,while the corresponding values during the northwest monsoon(NWM)season are 32 days,5569 km^(2),and-1.41×10^(5).It is also found that the SEM coastal upwelling in the NAS displays prominent interannual variability.The strong upwelling events are found in 2010,2013,2016,and 2017 when the southeast monsoon winds were weaker.Further analysis suggests that at the interannual scale,the upwelling index(UI)averaged in the SEM season is negatively correlated with that of three upwelling indicators.This can be attributed to the limitation of onshore geostrophic flow which is evidenced by the negative correlation between the UI and the alongshore difference in sea surface height.This study highlights the important role of the southeast monsoon in the temporal variability of coastal upwelling in the NAS.展开更多
Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear c...Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear characteristics and nonlinear behavior of the medium-to long-term shoreline evolution of Jinghai Bay,eastern Guangdong Province.In particular,shoreline rotation caused by a shore-normal coastal structure is emphasized.The results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach,with an average erosion rate of 3.1 m/a,and significant accretion on the northeast beach,with an average accretion rate of 5.6 m/a.Results of the M–K trend test indicate that significant shoreline changes occurred in early 2006,which can be attributed to shore-normal engineering.Prior to that engineering construction,the shorelines are slightly eroded,where the average erosion rate is 0.7 m/a.However,after shore-normal engineering is performed,the shoreline is characterized by significant erosion(3.2 m/a)on the southwest beach and significant accretion(8.5 m/a)on the northeast beach,thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline rotation.Further analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast,but also by cross-shore sediment transport processes.These findings are crucial for beach erosion risk management,coastal disaster zoning,regional sediment budget assessments,and further observations and predictions of beach morphodynamics.展开更多
Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)structures.Limited research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonun...Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)structures.Limited research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonuniform corrosion using different materials.In this study,a reliability-based design optimization(RBDO)procedure is improved for the design of coastal bridge piers using six groups of commonly used materials,i.e.,normal performance concrete(NPC)with black steel(BS)rebar,high strength steel(HSS)rebar,epoxy coated(EC)rebar,and stainless steel(SS)rebar(named NPC-BS,NPC-HSS,NPC-EC,and NPC-SS,respectively),NPC with BS with silane soakage on the pier surface(named NPC-Silane),and high-performance concrete(HPC)with BS rebar(named HPC-BS).First,the RBDO procedure is improved for the design optimization of coastal bridge piers,and a bridge is selected to illustrate the procedure.Then,reliability analysis of the pier designed with each group of materials is carried out to obtain the time-dependent reliability in terms of the ultimate and serviceability performances.Next,the repair time of the pier is predicted based on the time-dependent reliability indices.Finally,the time-dependent LCCs for the pier are obtained for the selection of the optimal design.展开更多
Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.I...Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.It is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located nearby.This study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water surface.The results show that the spill overall profile is articulated in three major flow areas.The first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill site.The behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the model.The Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.展开更多
High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However,...High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However, low frequency GPR surveys to investigate fault-related depositional systems at greater depths are scarce. This survey was designed investigate a > 100 km long linear escarpment that controls the northwest margin of the Lagoa do Peixe, an important lagoon in Rio Grande do Sul Coastal Plain (RGSCP, Brazil). The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;no deformational structure is admitted to exist before. The low frequency GPR (50 MHz, RTA antenna) and geological surveys carried out in the RGSCP showed the existence of a large, gravity-driven listric growth fault controlling the Lagoa do Peixe escarpment and hangingwall sedimentation. The radargrams in four subareas along the Lagoa do Peixe Growth Fault could be interpreted following the seismic expression of rift-related depositional systems. The radargrams enabled to distinguish three main lagoonal deposition radarfacies. The lower lagoonal radarfacies is a convex upward unit, thicker close to growth fault;the radarfacies geometry indicates that fault displacement rate surpasses the sedimentation rate, and its upper stratum is aged ~3500 <sup>l4</sup>C years BP. The second lagoonal radarfacies is a triangular wedge restricted to the lagoon depocenter, whose geometry indicates that fault displacement and the sedimentation rates kept pace. The upper lagoonal radarfacies is being deposited since 1060 ± 70 <sup>l4</sup>C years BP, under sedimentation rate higher than fault displacement rate. The results indicate that low frequency GPR surveys can help in investigating fault-related depositional systems in coastal zones. They also point to a new approach in dealing with RGSCP stratigraphy.展开更多
Rivers are progressively being exposed to increased anthropogenic pollution stresses that are undermining their designated uses and affecting sensitive coastal areas. In this study, three adjacent eastern Mediterranea...Rivers are progressively being exposed to increased anthropogenic pollution stresses that are undermining their designated uses and affecting sensitive coastal areas. In this study, three adjacent eastern Mediterranean coastal rivers, Ibrahim, Kaleb and Beirut, were evaluated. Water quality samples were collected in dry and wet seasons from different sampling sites along the river from the source to the outlet which represent a gradient of increased urbanization. The spatiotemporal variability of the physio-chemical properties, heavy metals (Zn, Pb, Cu, Cr, and Cd) and organic matter (DOC) were statistically analyzed to better understand the contribution of point and nonpoint pollution sources. The three rivers (Beirut, Kaleb and Ibrahim) show a similar behavior in calcium and carbonate alkalinity due to the carbonate mineral weathering effect, so they are of calcium bicarbonate type due to their calcareous geological nature. The speciation of anions was affected by temporal variation. Moreover, it is obvious that the Beirut River has a different behavioral characteristic where the water is a sulfate type water with a preferable metal-OM complexation mainly with lead, zinc and copper, whereas Kaleb and Ibrahim are considered to be of a nitrate phosphate type with a preferable metal inorganic complexation, especially copper, that has a consistent behavior in both types of waters. This difference is attributed to the urbanization effect highly impacting the Beirut River.展开更多
Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern Ch...Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.展开更多
This paper explains various factors that contribute to saltwater intrusion, including overexploitation of freshwater resources and climate change as well as the different techniques essential for effective saltwater i...This paper explains various factors that contribute to saltwater intrusion, including overexploitation of freshwater resources and climate change as well as the different techniques essential for effective saltwater intrusion management. The impact of saltwater intrusion along coastal regions and its impact on the environment, hydrogeology and groundwater contamination. It suggests potential solutions to mitigate the impact of saltwater intrusion, including effective water management and techniques for managing SWI. The application of A.I (assessment index) serves as a guideline to correctly identify wells with SWI ranging from no intrusion, slight intrusion and strong intrusion. The challenges of saltwater intrusion in Lagos and the salinization of wells were investigated using the hydro-chemical parameters. The study identifies four wells (“AA”, “CMS”, “OBA” and “VIL”) as having high electric conductivities, indicating saline water intrusion, while other wells (“EBM”, “IKJ, and “IKO”) with lower electric conductivities, indicate little or no salt-water intrusion, and “AJ” well shows slight intrusion. The elevation of the wells also played a vital role in the SWI across coastal regions of Lagos. The study recommends continuous monitoring of coastal wells to help sustain and reduce saline intrusion. The findings of the study are important for policymakers, researchers, and practitioners who are interested in addressing the challenges of saltwater intrusion along coastal regions. We assessed the SWI across the eight (8) wells using the Assessment Index to identify wells with SWI. Wells in “CMS” and “VIL” has strong intrusions. A proposed classification system based on specific ion ratios categorizes water quality from good (+) to highly (-) contaminated (refer to Table 4). These findings underscore the need for attention and effective management strategies to address groundwater unsuitability for various purposes.展开更多
The coastal zone of Benin is inherited from the last marine oscillations of the Quaternary. A rich and very fragile environment, it presented until the 1960s, a shoreline in dynamic equilibrium over the entire 125 km ...The coastal zone of Benin is inherited from the last marine oscillations of the Quaternary. A rich and very fragile environment, it presented until the 1960s, a shoreline in dynamic equilibrium over the entire 125 km of coastal line. Since the 1960s, with the construction of important development infrastructures (ports, dams, groins), the Beninese coast is now subject to risks of coastal erosion and seasonal flooding due to the overflow of lagoon water bodies. The present study, based on socio-economic surveys in the communes of Ouidah, Comè and Grand Popo, exposes the extent of coastal risks and socio-economic and environmental damage in the southwestern coastal zone of Benin. The results show that in terms of land, 2.9 ha and 5.7 ha of land have been permanently lost to coastal erosion in the communes of Ouidah and Grand Popo respectively. Similarly, 212 ha of crops of all types were affected by the flooding, including 35 ha destroyed, i.e. 6.67 ha, 11.3 ha in Comè, 4.67 ha Ouidah and 14 ha Grand Popo. Also, 6435 buildings were affected, and 4235 huts were damaged. In addition, working tools, food stocks and other items are counted among the losses recorded by coastal hazards with their corollaries of diseases. The cost of losses and damages in the 08 districts amount to 418,000,000f cfa of which 266,000,000f cfa of damage and 152,000,000f cfa of loss.展开更多
Coastal erosion on islands is increasing due to sea level rise,frequent extreme events,and anthropogenic activities.However,studies on the multifactorial coastal erosion risk and the vulnerability of islands are limit...Coastal erosion on islands is increasing due to sea level rise,frequent extreme events,and anthropogenic activities.However,studies on the multifactorial coastal erosion risk and the vulnerability of islands are limited.In this study,the Coastal Erosion Risk Assessment(CERA)method was applied for the first time to the study area in China to assess the erosion risk on the coast of Hainan Island;to explore the effects of coastal ocean dynamics,sediment movement characteristics,and anthropogenic construction;and to discuss the suitability of the method and countermeasures for coastal protection.The results show that the coast of Hainan Island shows high sensitivity,high value,low exposure,and moderate erosion.The whole island showed high vulnerability but low erosion risk,with the eastern region being more affected by erosion,particularly the eastern side of Wulong Port and Yalin Bay in Wenchang,and the shore section of Yalong Bay in Sanya,having a very high risk of coastal erosion.In addition,Monte Carlo simulation was used to check the applicability of the CERA method,and it was found that the rate of shoreline change,population density,and number of storms significantly contributed to coastal erosion,but only the short-term effects of sea level rise were considered.The effects of sea level rise and sediment grain size were primarily analyzed as influencing factors.The effects of sea level rise continue to strengthen,with coastal retreat expected to be greater than 2 m by the mid-21st century.Moreover,Hainan Island is primarily composed of the fine and medium sand types,which have little resistance to coastal erosion.Currently,the impact of sediment grain size is rarely considered in coastal erosion risk assessment studies.However,it can be incorporated into the indicator system in the future,and the spatial variation of indicators can be fully considered to strengthen the refinement study.展开更多
Coastline changes were analyzed considering the land cover types and the analysis of the causes that have determined these changes during the past decades.Through the overlapping of aerial photographs and GIS an...Coastline changes were analyzed considering the land cover types and the analysis of the causes that have determined these changes during the past decades.Through the overlapping of aerial photographs and GIS analysis,the results showed that the land surface increased with respect to the previous stage,gaining terrain to the sea,but this increment was caused by anthropogenic processes.In fact,without human pressure,the land surface beside the coastal line would have decreased,especially on the sandy beaches and coastal dunes.Therefore,the beaches are one of the most vulnerable ecosystems and geomorphological systems due to erosion and lack of sediment supply associated with the modified river courses(i.e.by the construction of reservoirs,concrete channeling,etc.),the inner land use changes,and the effects of global warming on the sea level.Climate change studies predict specific increases in the sea level along the coast.The aim of this work is to know if anthropic activity can reverse the effects of sea level rise and coastal erosion.In fact,it has been done for decades with measures aimed to correct impacts and favour economic activity(i.e.maintaining tourism resources)and not from the environmental issues.展开更多
China’s coastal wetlands provide breeding,migration stopover,and wintering habitats for about 230 waterbird species,which is more than a quarter of all waterbirds in the world.Large-scale and high intensity human act...China’s coastal wetlands provide breeding,migration stopover,and wintering habitats for about 230 waterbird species,which is more than a quarter of all waterbirds in the world.Large-scale and high intensity human activities have resulted in serious loss and degradation of coastal wetlands over the past half century,causing population declines in many waterbirds.Through a literature review and expert surveys,this article reviews conservation measures taken in recent decades to protect waterbirds in China’s coastal wetlands and provides recommendations for future conservation action from three aspects:policy and administration,habitat conservation and management,and multiparty participation.Over the past decades,many conservation legislation,regulations and action plans at the national level and more site-specific measures and interventions have been implemented,with notable improvement in the effectiveness in policy making and multi-stakeholder participation.Accordingly,some threats to waterbirds have been mitigated and many key sites for waterbirds have been designated as strictly protected nature reserves.However,some critical issues still remain,mostly related to habitat conservation and management,such as coastal wetland restoration,control of invasive Spartina alterniflora,control of environmental pollution,and improvement of artificial habitat quality.We highlight that protecting natural tidal wetlands and improving habitat quality are critical for the conservation of coastal waterbirds,especially those highly dependent on the intertidal wetlands.China has demonstrated strong commitment to ecological conservation and restoration for the future,in terms of both funding and policies for biodiversity and wetland ecosystems.It is important that this commitment to conserve coastal waterbirds is supported continuously by science-and evidence-based decisions and actions.展开更多
The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here...The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here,we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019.Brassicasterol/epi-brassicasterol,dinosterol,and C37 alkenones were used as proxies of biomass for diatoms,dinoflagellates,and haptophytes,respectively,and their sum indicating total phytoplankton biomass.A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents.Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area;however,the two currents had distinct effects on the spatial distribution of phytoplankton.For phytoplankton biomass,the eutrophic coastal currents were likely to be the main controlling factors,while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites.For phytoplankton community structures,the Kuroshio and its intrusion were the main factors,resulting in an increase in the proportions of dinoflagellates and haptophytes.The proportion of diatoms slightly increased due to the influence of the coastal currents.Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters,providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions.展开更多
This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkl...This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkler irrigation in three stages was used to regulate soil matric potential at a 20-cm soil depth.Continued regulation of soil water and salt through micro-sprinkler irrigation consistently resulted in an increasingly large low-salinity region.The application of the three stages of soil wateresalt regulation resulted in an absence of salt accumulation throughout the soil profile and the conversion of highly saline soils into moderately saline soils.There were increases in the plant height,leaf width,leaf length,and tiller numbers of tall fescue throughout the leaching process.The results showed that micro-sprinkler irrigation in three soil water and salt regulation stages can be used to successfully cultivate tall festuca in highly saline coastal soil.This approach achieved better effects in sandy loam soil than in silt soil.Tall fescue showed greater survival rates in sandy loam soil due to the rapid reclamation process,whereas plant growth was higher in silt soil because of effective water conservation.In sandy loam,soil moisture should be maintained during soil reclamation,and in silt soil,soil root-zone environments optimal for the emergence of plants should be quickly established.Micro-sprinkler irrigation can be successfully applied to the cultivation of tall fescue in coastal heavy saline soils under a three-stage soil wateresalt regulation regime.展开更多
Increasing intense human activities have largely changed the coastal landscape and caused many environmental issues.However,whether human-induced activities could change the coastal land use gradient pattern,an import...Increasing intense human activities have largely changed the coastal landscape and caused many environmental issues.However,whether human-induced activities could change the coastal land use gradient pattern,an important coastal zonal characteristic along the sea-land direction,remains unclear.Manila Bay was selected as the study area in this work.According to the distance of the land use and land cover(LULC)to the coastline,we clustered the typical coastal land use sequence patterns(CLUSPs)along the sea-land direction between 1988 and 2016 in Manila Bay and found the following.(1)Four typical CLUSPs,including the natural CLUSP dominated by forest land and grassland,the agricultural CLUSP dominated by dry farm and paddy field,the urbanised CLUSP dominated by construction land and the fishery CLUSP dominated by fishing farm,were mined in 1988.Three typical CLUSPs(a natural CLUSP,an intermediate CLUSP between the agricultural and urbanised CLUSPs,and a fishery CLUSP)were mined in 2016.(2)Affected by the dominant LULC,these typical CLUSPs showed a regular spatial pattern along the sea-land direction.For example,the typical natural CLUSP showed a landward pattern due to the long distance between the forest land and grassland and the coastline.(3)However,influenced by urban and aquaculture expansion,the land intensification of the CLUSP exhibited an obvious increase and caused the decrease of the CLUSP diversity from 1988 to 2016.The increase in the area of LULC coverage showed no obvious correlation with its distance from the coastline(DFC),but the net increase rate of LULC coverage had a significant negative correlation with the DFC.Therefore,human-induced activities have a large impact on the gradient pattern of coastal land use along the sea-land direction.展开更多
The change of coastal wetland vulnerability affects the ecological environment and the economic development of the estuary area.In the past,most of the assessment studies on the vulnerability of coastal ecosystems sta...The change of coastal wetland vulnerability affects the ecological environment and the economic development of the estuary area.In the past,most of the assessment studies on the vulnerability of coastal ecosystems stayed in static qualitative research,lacking predictability,and the qualitative and quantitative relationship was not objective enough.In this study,the“Source-Pathway-Receptor-Consequence”model and the Intergovernmental Panel on Climate Change vulnerability definition were used to analyze the main impact of sea level rise caused by climate change on coastal wetland ecosystem in Minjiang River Estuary.The results show that:(1)With the increase of time and carbon emission,the area of high vulnerability and the higher vulnerability increased continuously,and the area of low vulnerability and the lower vulnerability decreased.(2)The eastern and northeastern part of the Culu Island in the Minjiang River Estuary of Fujian Province and the eastern coastal wetland of Meihua Town in Changle District are areas with high vulnerability risk.The area of high vulnerability area of coastal wetland under high emission scenario is wider than that under low emission scenario.(3)Under different sea level rise scenarios,elevation has the greatest impact on the vulnerability of coastal wetlands,and slope has less impact.The impact of sea level rise caused by climate change on the coastal wetland ecosystem in the Minjiang River Estuary is mainly manifested in the sea level rise,which changes the habitat elevation and daily flooding time of coastal wetlands,and then affects the survival and distribution of coastal wetland ecosystems.展开更多
Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan c...Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan coastal waters,explore the differences and applicability of two gene fragments(12S rRNA and COI)of DNA barcoding in fish species identification,and established a comprehensive fish barcoding reference database.Two hundred and eighty-seven captured fish samples from Zhoushan coastal waters were identified using morphological characteristics and DNA barcoding.A total of 26412S rRNA sequences(belonging to eight orders,31 families,55 genera,and 66 species)and 188 COI sequences(belonging to seven orders,30 families,48 genera,and 58 species)were obtained.The lengths of the 12S rRNA sequences ranged from 165 to 178 bp,and the guanine-cytosine(GC)content was 45.37%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.10%and 26.66%,respectively.The length of the COI sequence ranged 574–655 bp,and the content of GC was 45.97%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.16%and 27.45%,respectively.The minimum interspecific genetic distances of 12S rRNA and COI(1.23%and 1.86%)were both greater than their maximum intraspecific genetic distances(2.42%and 8.66%).Three molecular analyses(NJ tree,ABGD,and GMYC)were performed to accurately identify and delineate species.Clustering errors occurred when the 12S rRNA sequences were delimited using the NJ tree method,and the delimitation results of ABGD and GMYC are consistent with the final species identification results.Our results demonstrate that DNA barcoding based on 12S rRNA and COI can be used as an effective tool for fish species identification,and 12S rRNA has good application prospects in the environmental DNA(eDNA)metabarcoding of marine fish.展开更多
基金supported by the National Natural Science Foundation of China(No.42077219)the Ningbo Municipal Natural Science Foundation(No.2019A610443)+1 种基金the Hangzhou Municipal Agriculture and Social Development Project(No.2020ZDSJ0697)the Fundamental Research Funds for the Provincial Universities of Zhejiang(No.SJLY2020011)
文摘Globally,various types of pollution affect coastal waters as a result of human activities.Bioaugmentation and biostimulation are effective methods for treating water pollution.However,few studies have explored the response of coastal prokaryotic and eukaryotic communities to bioaugmentation and biostimulation.Here,a 28-day outdoor mesocosm experiment with two treatments(bioaugmentation-A and combined treatment of bioaugmentation and biostimulation-AS)and a control(untreated-C)were carried out.The experiment was conducted in Meishan Bay to explore the composition,dynamics,and co-occurrence patterns of prokaryotic and eukaryotic communities in response to the A and AS using 16S rRNA and 18S rRNA gene amplicon sequencing.After treatment,Gammaproteobacteria and Epsilonproteobacteria were significantly increased in group AS compared to group C,while Flavobacteriia and Saprospirae were significantly reduced.Dinoflagellata was significantly reduced in AS compared to C,while Chrysophyta was significantly reduced in both AS and A.Compared to C,the principal response curve analyses of the prokaryotic and eukaryotic communities both showed an increasing trend followed by a decreasing trend for AS.Furthermore,the trends of prokaryotic and eukaryotic communities in group A were similar to those in group AS compared with group C,but AS changed them more than A did.According to the species weight table on principal response curves,a significant increase was observed in beneficial bacteria in prokaryotic communities,such as Rhodobacterales and Oceanospirillales,along with a decrease in autotrophs in eukaryotic communities,such as Chrysophyta and Diatom.Topological properties of network analysis reveal that A and AS complicate the interactions between the prokaryotic and eukaryotic communities.Overall,these findings expand our understanding of the response pattern of the bioaugmentation and biostimulation on coastal prokaryotic and eukaryotic communities.
基金Supported by the National Key R&D Program of China (No.2018YFD0900803)the China Agriculture Research System of MOF and MARA (No.CARS-47)the Central Public-Interest Scientific Institution Basal Research Fund (Nos.2021JC01,20603022022024)
文摘The first record of abnormal body coloration in Sebastes koreanus Kim and Lee,1994,from the Yellow Sea of China,was documented based on morphological characteristics and DNA barcoding.The two rockfish specimens were collected from the coastal waters of Qingdao,China,and the whole body and all fins of them were red.Of the two red-colored rockfish,there were tiny deep red spots on each fin,2 red radial stripes behind and below the eyes and 1 large deep red blotch on the opercula,while the similar stripe and spot patterns are also present in the S.koreanus specimens with normal body coloration.The countable characteristics of the two specimens are in the range of the morphometry of S.koreanus.To further clarify the species identity and taxonomic status of the two specimens,DNA barcode analysis was carried out.The genetic distance between the red-colored rockfish and S.koreanus was 0,and the minimum net genetic distances between the red-colored rockfish and other Sebastes species except for S.koreanus were 3.0%,which exceeds the threshold of species delimitation.The phylogenetic analysis showed that the DNA barcoding sequences of the two red-colored rockfish clustered with the S.koreanus sequences.The above results of DNA barcode analysis also support that the two red-colored rockfish could be identified as the species of S.koreanus.The mechanism of color variation in S.koreanus is desirable for further research and the species could be an ideal model to study the color-driven speciation of the rockfishes.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB 42000000)the National Natural Science Foundation of China(No.92258301)+2 种基金the Scientific and Technological Innovation Project financially supported by Laoshan Laboratory(No.LSKJ202202502)the CAS Key Deployment Project of Center for Ocean Mega-Research of Science(No.COMS2020Q07)the CAS-CSIRO Jointly Project(No.133244KYSB20190031)。
文摘Coastal upwelling is significant for marine ecosystems by lifting nutrient-rich deep waters into the euphotic zone,thereby increasing primary and secondary productivity.The satellite observations show that the northern Arafura Sea(NAS),especially in the coastal region,features high chlorophyll-a(chl-a)concentrations,implying a strong coastal upwelling.However,coastal upwelling in the NAS has not received much attention.Based on a semi-automatic image processing technology,the seasonal and interannual variability of coastal upwelling in the NAS are investigated in this study using satellite-observed sea surface temperature(SST)and wind data.The results suggest that there are seasonal coastal upwelling events in the NAS modulated by upwelling-favorable southeast monsoon(SEM).The annual mean days,mean area,and annual mean intensity of coastal upwelling events during the SEM season are 92 days,6514 km^(2),and-5.31×10^(5),respectively,while the corresponding values during the northwest monsoon(NWM)season are 32 days,5569 km^(2),and-1.41×10^(5).It is also found that the SEM coastal upwelling in the NAS displays prominent interannual variability.The strong upwelling events are found in 2010,2013,2016,and 2017 when the southeast monsoon winds were weaker.Further analysis suggests that at the interannual scale,the upwelling index(UI)averaged in the SEM season is negatively correlated with that of three upwelling indicators.This can be attributed to the limitation of onshore geostrophic flow which is evidenced by the negative correlation between the UI and the alongshore difference in sea surface height.This study highlights the important role of the southeast monsoon in the temporal variability of coastal upwelling in the NAS.
基金The National Nature Science Foundation of China under contract No.42071007the Nature Science Foundation of Hainan Province under contract Nos 422RC665,421QN0883,and 423RC553。
文摘Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear characteristics and nonlinear behavior of the medium-to long-term shoreline evolution of Jinghai Bay,eastern Guangdong Province.In particular,shoreline rotation caused by a shore-normal coastal structure is emphasized.The results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach,with an average erosion rate of 3.1 m/a,and significant accretion on the northeast beach,with an average accretion rate of 5.6 m/a.Results of the M–K trend test indicate that significant shoreline changes occurred in early 2006,which can be attributed to shore-normal engineering.Prior to that engineering construction,the shorelines are slightly eroded,where the average erosion rate is 0.7 m/a.However,after shore-normal engineering is performed,the shoreline is characterized by significant erosion(3.2 m/a)on the southwest beach and significant accretion(8.5 m/a)on the northeast beach,thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline rotation.Further analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast,but also by cross-shore sediment transport processes.These findings are crucial for beach erosion risk management,coastal disaster zoning,regional sediment budget assessments,and further observations and predictions of beach morphodynamics.
基金National Natural Science Foundation of China under Grant Nos.51921006 and 51725801Fundamental Research Funds for the Central Universities under Grant No.FRFCU5710093320Heilongjiang Touyan Innovation Team Program。
文摘Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)structures.Limited research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonuniform corrosion using different materials.In this study,a reliability-based design optimization(RBDO)procedure is improved for the design of coastal bridge piers using six groups of commonly used materials,i.e.,normal performance concrete(NPC)with black steel(BS)rebar,high strength steel(HSS)rebar,epoxy coated(EC)rebar,and stainless steel(SS)rebar(named NPC-BS,NPC-HSS,NPC-EC,and NPC-SS,respectively),NPC with BS with silane soakage on the pier surface(named NPC-Silane),and high-performance concrete(HPC)with BS rebar(named HPC-BS).First,the RBDO procedure is improved for the design optimization of coastal bridge piers,and a bridge is selected to illustrate the procedure.Then,reliability analysis of the pier designed with each group of materials is carried out to obtain the time-dependent reliability in terms of the ultimate and serviceability performances.Next,the repair time of the pier is predicted based on the time-dependent reliability indices.Finally,the time-dependent LCCs for the pier are obtained for the selection of the optimal design.
文摘Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.It is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located nearby.This study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water surface.The results show that the spill overall profile is articulated in three major flow areas.The first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill site.The behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the model.The Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.
文摘High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However, low frequency GPR surveys to investigate fault-related depositional systems at greater depths are scarce. This survey was designed investigate a > 100 km long linear escarpment that controls the northwest margin of the Lagoa do Peixe, an important lagoon in Rio Grande do Sul Coastal Plain (RGSCP, Brazil). The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;no deformational structure is admitted to exist before. The low frequency GPR (50 MHz, RTA antenna) and geological surveys carried out in the RGSCP showed the existence of a large, gravity-driven listric growth fault controlling the Lagoa do Peixe escarpment and hangingwall sedimentation. The radargrams in four subareas along the Lagoa do Peixe Growth Fault could be interpreted following the seismic expression of rift-related depositional systems. The radargrams enabled to distinguish three main lagoonal deposition radarfacies. The lower lagoonal radarfacies is a convex upward unit, thicker close to growth fault;the radarfacies geometry indicates that fault displacement rate surpasses the sedimentation rate, and its upper stratum is aged ~3500 <sup>l4</sup>C years BP. The second lagoonal radarfacies is a triangular wedge restricted to the lagoon depocenter, whose geometry indicates that fault displacement and the sedimentation rates kept pace. The upper lagoonal radarfacies is being deposited since 1060 ± 70 <sup>l4</sup>C years BP, under sedimentation rate higher than fault displacement rate. The results indicate that low frequency GPR surveys can help in investigating fault-related depositional systems in coastal zones. They also point to a new approach in dealing with RGSCP stratigraphy.
文摘Rivers are progressively being exposed to increased anthropogenic pollution stresses that are undermining their designated uses and affecting sensitive coastal areas. In this study, three adjacent eastern Mediterranean coastal rivers, Ibrahim, Kaleb and Beirut, were evaluated. Water quality samples were collected in dry and wet seasons from different sampling sites along the river from the source to the outlet which represent a gradient of increased urbanization. The spatiotemporal variability of the physio-chemical properties, heavy metals (Zn, Pb, Cu, Cr, and Cd) and organic matter (DOC) were statistically analyzed to better understand the contribution of point and nonpoint pollution sources. The three rivers (Beirut, Kaleb and Ibrahim) show a similar behavior in calcium and carbonate alkalinity due to the carbonate mineral weathering effect, so they are of calcium bicarbonate type due to their calcareous geological nature. The speciation of anions was affected by temporal variation. Moreover, it is obvious that the Beirut River has a different behavioral characteristic where the water is a sulfate type water with a preferable metal-OM complexation mainly with lead, zinc and copper, whereas Kaleb and Ibrahim are considered to be of a nitrate phosphate type with a preferable metal inorganic complexation, especially copper, that has a consistent behavior in both types of waters. This difference is attributed to the urbanization effect highly impacting the Beirut River.
基金This research is supported by Hunan Provincial Natural Science Foundation of China(Grant No.2021JJ30304)the General Topics of Hunan Social Science Achievement Evaluation Committee of China(Grant No.XSP22YBC366)the Key Scientific Research Project of Hunan Provincial Department of Education of China(Grant No.21B0592).
文摘Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.
文摘This paper explains various factors that contribute to saltwater intrusion, including overexploitation of freshwater resources and climate change as well as the different techniques essential for effective saltwater intrusion management. The impact of saltwater intrusion along coastal regions and its impact on the environment, hydrogeology and groundwater contamination. It suggests potential solutions to mitigate the impact of saltwater intrusion, including effective water management and techniques for managing SWI. The application of A.I (assessment index) serves as a guideline to correctly identify wells with SWI ranging from no intrusion, slight intrusion and strong intrusion. The challenges of saltwater intrusion in Lagos and the salinization of wells were investigated using the hydro-chemical parameters. The study identifies four wells (“AA”, “CMS”, “OBA” and “VIL”) as having high electric conductivities, indicating saline water intrusion, while other wells (“EBM”, “IKJ, and “IKO”) with lower electric conductivities, indicate little or no salt-water intrusion, and “AJ” well shows slight intrusion. The elevation of the wells also played a vital role in the SWI across coastal regions of Lagos. The study recommends continuous monitoring of coastal wells to help sustain and reduce saline intrusion. The findings of the study are important for policymakers, researchers, and practitioners who are interested in addressing the challenges of saltwater intrusion along coastal regions. We assessed the SWI across the eight (8) wells using the Assessment Index to identify wells with SWI. Wells in “CMS” and “VIL” has strong intrusions. A proposed classification system based on specific ion ratios categorizes water quality from good (+) to highly (-) contaminated (refer to Table 4). These findings underscore the need for attention and effective management strategies to address groundwater unsuitability for various purposes.
文摘The coastal zone of Benin is inherited from the last marine oscillations of the Quaternary. A rich and very fragile environment, it presented until the 1960s, a shoreline in dynamic equilibrium over the entire 125 km of coastal line. Since the 1960s, with the construction of important development infrastructures (ports, dams, groins), the Beninese coast is now subject to risks of coastal erosion and seasonal flooding due to the overflow of lagoon water bodies. The present study, based on socio-economic surveys in the communes of Ouidah, Comè and Grand Popo, exposes the extent of coastal risks and socio-economic and environmental damage in the southwestern coastal zone of Benin. The results show that in terms of land, 2.9 ha and 5.7 ha of land have been permanently lost to coastal erosion in the communes of Ouidah and Grand Popo respectively. Similarly, 212 ha of crops of all types were affected by the flooding, including 35 ha destroyed, i.e. 6.67 ha, 11.3 ha in Comè, 4.67 ha Ouidah and 14 ha Grand Popo. Also, 6435 buildings were affected, and 4235 huts were damaged. In addition, working tools, food stocks and other items are counted among the losses recorded by coastal hazards with their corollaries of diseases. The cost of losses and damages in the 08 districts amount to 418,000,000f cfa of which 266,000,000f cfa of damage and 152,000,000f cfa of loss.
基金The National Natural Science Foundation of China under contract No.42176167the Innovation Fund of Guangdong Ocean University under contract No.Q18307the Postgraduate Education Innovation Project of Guangdong Ocean University under contract No.202252.
文摘Coastal erosion on islands is increasing due to sea level rise,frequent extreme events,and anthropogenic activities.However,studies on the multifactorial coastal erosion risk and the vulnerability of islands are limited.In this study,the Coastal Erosion Risk Assessment(CERA)method was applied for the first time to the study area in China to assess the erosion risk on the coast of Hainan Island;to explore the effects of coastal ocean dynamics,sediment movement characteristics,and anthropogenic construction;and to discuss the suitability of the method and countermeasures for coastal protection.The results show that the coast of Hainan Island shows high sensitivity,high value,low exposure,and moderate erosion.The whole island showed high vulnerability but low erosion risk,with the eastern region being more affected by erosion,particularly the eastern side of Wulong Port and Yalin Bay in Wenchang,and the shore section of Yalong Bay in Sanya,having a very high risk of coastal erosion.In addition,Monte Carlo simulation was used to check the applicability of the CERA method,and it was found that the rate of shoreline change,population density,and number of storms significantly contributed to coastal erosion,but only the short-term effects of sea level rise were considered.The effects of sea level rise and sediment grain size were primarily analyzed as influencing factors.The effects of sea level rise continue to strengthen,with coastal retreat expected to be greater than 2 m by the mid-21st century.Moreover,Hainan Island is primarily composed of the fine and medium sand types,which have little resistance to coastal erosion.Currently,the impact of sediment grain size is rarely considered in coastal erosion risk assessment studies.However,it can be incorporated into the indicator system in the future,and the spatial variation of indicators can be fully considered to strengthen the refinement study.
基金Acknowledge to the National Geographic Institute for supporting the free access and availability of geographical data for researchers.
文摘Coastline changes were analyzed considering the land cover types and the analysis of the causes that have determined these changes during the past decades.Through the overlapping of aerial photographs and GIS analysis,the results showed that the land surface increased with respect to the previous stage,gaining terrain to the sea,but this increment was caused by anthropogenic processes.In fact,without human pressure,the land surface beside the coastal line would have decreased,especially on the sandy beaches and coastal dunes.Therefore,the beaches are one of the most vulnerable ecosystems and geomorphological systems due to erosion and lack of sediment supply associated with the modified river courses(i.e.by the construction of reservoirs,concrete channeling,etc.),the inner land use changes,and the effects of global warming on the sea level.Climate change studies predict specific increases in the sea level along the coast.The aim of this work is to know if anthropic activity can reverse the effects of sea level rise and coastal erosion.In fact,it has been done for decades with measures aimed to correct impacts and favour economic activity(i.e.maintaining tourism resources)and not from the environmental issues.
基金financially supported by National Key Research and Development Program of China (2022YFF1301004)the National Natural Science Foundation of China (31830089 and 32170518)TP’s work in the East Asian-Australasian Flyway through Global Flyway Network was supported by WWF-Netherlands,the MAVA Foundation and many other benefactors
文摘China’s coastal wetlands provide breeding,migration stopover,and wintering habitats for about 230 waterbird species,which is more than a quarter of all waterbirds in the world.Large-scale and high intensity human activities have resulted in serious loss and degradation of coastal wetlands over the past half century,causing population declines in many waterbirds.Through a literature review and expert surveys,this article reviews conservation measures taken in recent decades to protect waterbirds in China’s coastal wetlands and provides recommendations for future conservation action from three aspects:policy and administration,habitat conservation and management,and multiparty participation.Over the past decades,many conservation legislation,regulations and action plans at the national level and more site-specific measures and interventions have been implemented,with notable improvement in the effectiveness in policy making and multi-stakeholder participation.Accordingly,some threats to waterbirds have been mitigated and many key sites for waterbirds have been designated as strictly protected nature reserves.However,some critical issues still remain,mostly related to habitat conservation and management,such as coastal wetland restoration,control of invasive Spartina alterniflora,control of environmental pollution,and improvement of artificial habitat quality.We highlight that protecting natural tidal wetlands and improving habitat quality are critical for the conservation of coastal waterbirds,especially those highly dependent on the intertidal wetlands.China has demonstrated strong commitment to ecological conservation and restoration for the future,in terms of both funding and policies for biodiversity and wetland ecosystems.It is important that this commitment to conserve coastal waterbirds is supported continuously by science-and evidence-based decisions and actions.
基金The study was supported by the National Natural Science Foundation of China(No.41876118)the Global Climate Changes and Air-Sea Interaction Program(No.GASI-02-PAC-ST-Wwin)This is MCTL(Key Laboratory of Marine Chemistry Theory and Technology)contribution#281.
文摘The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here,we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019.Brassicasterol/epi-brassicasterol,dinosterol,and C37 alkenones were used as proxies of biomass for diatoms,dinoflagellates,and haptophytes,respectively,and their sum indicating total phytoplankton biomass.A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents.Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area;however,the two currents had distinct effects on the spatial distribution of phytoplankton.For phytoplankton biomass,the eutrophic coastal currents were likely to be the main controlling factors,while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites.For phytoplankton community structures,the Kuroshio and its intrusion were the main factors,resulting in an increase in the proportions of dinoflagellates and haptophytes.The proportion of diatoms slightly increased due to the influence of the coastal currents.Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters,providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions.
基金supported by the China Scholarship Council(Grant No.201906715015)the Priority Academic Development Program of Jiangsu Higher Education Institutions.
文摘This study aimed to investigate whether saline silt and sandy loam coastal soils could be reclaimed by micro-sprinkler irrigation.The experiments were run using moderately salt-tolerant tall fescue grass.Micro-sprinkler irrigation in three stages was used to regulate soil matric potential at a 20-cm soil depth.Continued regulation of soil water and salt through micro-sprinkler irrigation consistently resulted in an increasingly large low-salinity region.The application of the three stages of soil wateresalt regulation resulted in an absence of salt accumulation throughout the soil profile and the conversion of highly saline soils into moderately saline soils.There were increases in the plant height,leaf width,leaf length,and tiller numbers of tall fescue throughout the leaching process.The results showed that micro-sprinkler irrigation in three soil water and salt regulation stages can be used to successfully cultivate tall festuca in highly saline coastal soil.This approach achieved better effects in sandy loam soil than in silt soil.Tall fescue showed greater survival rates in sandy loam soil due to the rapid reclamation process,whereas plant growth was higher in silt soil because of effective water conservation.In sandy loam,soil moisture should be maintained during soil reclamation,and in silt soil,soil root-zone environments optimal for the emergence of plants should be quickly established.Micro-sprinkler irrigation can be successfully applied to the cultivation of tall fescue in coastal heavy saline soils under a three-stage soil wateresalt regulation regime.
基金The Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences under contract No.ISEE2020YB06the National Natural Science Foundation of China under contract Nos 41830648 and 41801353+3 种基金the Chongqing Postdoctoral Innovation Fund under contract No.cstc2020jcyj-bshX0103the Grant from the State Key Laboratory of Resources and Environmental Information Systemthe Open Project Programme of the Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions under contract No.GTYR201906the Open Project Programme of Chongqing Key Laboratory of Karst Environment under contract No.Cqk201903.
文摘Increasing intense human activities have largely changed the coastal landscape and caused many environmental issues.However,whether human-induced activities could change the coastal land use gradient pattern,an important coastal zonal characteristic along the sea-land direction,remains unclear.Manila Bay was selected as the study area in this work.According to the distance of the land use and land cover(LULC)to the coastline,we clustered the typical coastal land use sequence patterns(CLUSPs)along the sea-land direction between 1988 and 2016 in Manila Bay and found the following.(1)Four typical CLUSPs,including the natural CLUSP dominated by forest land and grassland,the agricultural CLUSP dominated by dry farm and paddy field,the urbanised CLUSP dominated by construction land and the fishery CLUSP dominated by fishing farm,were mined in 1988.Three typical CLUSPs(a natural CLUSP,an intermediate CLUSP between the agricultural and urbanised CLUSPs,and a fishery CLUSP)were mined in 2016.(2)Affected by the dominant LULC,these typical CLUSPs showed a regular spatial pattern along the sea-land direction.For example,the typical natural CLUSP showed a landward pattern due to the long distance between the forest land and grassland and the coastline.(3)However,influenced by urban and aquaculture expansion,the land intensification of the CLUSP exhibited an obvious increase and caused the decrease of the CLUSP diversity from 1988 to 2016.The increase in the area of LULC coverage showed no obvious correlation with its distance from the coastline(DFC),but the net increase rate of LULC coverage had a significant negative correlation with the DFC.Therefore,human-induced activities have a large impact on the gradient pattern of coastal land use along the sea-land direction.
基金The National Natural Science Foundation of China under contract No.U22A20585the Education Research Project of Fujian Education Department under contract No.JAT200019.
文摘The change of coastal wetland vulnerability affects the ecological environment and the economic development of the estuary area.In the past,most of the assessment studies on the vulnerability of coastal ecosystems stayed in static qualitative research,lacking predictability,and the qualitative and quantitative relationship was not objective enough.In this study,the“Source-Pathway-Receptor-Consequence”model and the Intergovernmental Panel on Climate Change vulnerability definition were used to analyze the main impact of sea level rise caused by climate change on coastal wetland ecosystem in Minjiang River Estuary.The results show that:(1)With the increase of time and carbon emission,the area of high vulnerability and the higher vulnerability increased continuously,and the area of low vulnerability and the lower vulnerability decreased.(2)The eastern and northeastern part of the Culu Island in the Minjiang River Estuary of Fujian Province and the eastern coastal wetland of Meihua Town in Changle District are areas with high vulnerability risk.The area of high vulnerability area of coastal wetland under high emission scenario is wider than that under low emission scenario.(3)Under different sea level rise scenarios,elevation has the greatest impact on the vulnerability of coastal wetlands,and slope has less impact.The impact of sea level rise caused by climate change on the coastal wetland ecosystem in the Minjiang River Estuary is mainly manifested in the sea level rise,which changes the habitat elevation and daily flooding time of coastal wetlands,and then affects the survival and distribution of coastal wetland ecosystems.
基金Supported by the Zhejiang Provincial Key Research and Development Program (No.2021C02047)。
文摘Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan coastal waters,explore the differences and applicability of two gene fragments(12S rRNA and COI)of DNA barcoding in fish species identification,and established a comprehensive fish barcoding reference database.Two hundred and eighty-seven captured fish samples from Zhoushan coastal waters were identified using morphological characteristics and DNA barcoding.A total of 26412S rRNA sequences(belonging to eight orders,31 families,55 genera,and 66 species)and 188 COI sequences(belonging to seven orders,30 families,48 genera,and 58 species)were obtained.The lengths of the 12S rRNA sequences ranged from 165 to 178 bp,and the guanine-cytosine(GC)content was 45.37%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.10%and 26.66%,respectively.The length of the COI sequence ranged 574–655 bp,and the content of GC was 45.97%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.16%and 27.45%,respectively.The minimum interspecific genetic distances of 12S rRNA and COI(1.23%and 1.86%)were both greater than their maximum intraspecific genetic distances(2.42%and 8.66%).Three molecular analyses(NJ tree,ABGD,and GMYC)were performed to accurately identify and delineate species.Clustering errors occurred when the 12S rRNA sequences were delimited using the NJ tree method,and the delimitation results of ABGD and GMYC are consistent with the final species identification results.Our results demonstrate that DNA barcoding based on 12S rRNA and COI can be used as an effective tool for fish species identification,and 12S rRNA has good application prospects in the environmental DNA(eDNA)metabarcoding of marine fish.
