The Anthropocene is being considered as a new geological epoch because human activities now rival geological forces to radically alter the natural state and functioning of the Earth system,producing its own distinctiv...The Anthropocene is being considered as a new geological epoch because human activities now rival geological forces to radically alter the natural state and functioning of the Earth system,producing its own distinctive sedimentary records(Waters et al.2016).These changes of varied magnitude can be traced over different spatiotemporal scales.展开更多
The present study uses nine machine learning(ML)methods to predict wave runup in an innovative and comprehensive methodology.Unlike previous investigations,which often limited the factors considered when applying ML m...The present study uses nine machine learning(ML)methods to predict wave runup in an innovative and comprehensive methodology.Unlike previous investigations,which often limited the factors considered when applying ML methodologies to predict wave runup,this approach takes a holistic perspective.The analysis takes into account a comprehensive range of crucial coastal parameters,including the 2%exceedance value for runup,setup,total swash excursion,incident swash,infragravity swash,significant wave height,peak wave period,foreshore beach slope,and median sediment size.Model performance,interpretability,and practicality were assessed.The findings from this study showes that linear models,while valuable in many applications,proved insufficient in grasping the complexity of this dataset.On the other hand,we found that non-linear models are essential for achieving accurate wave runup predictions,underscoring their significance in the context of the research.Within the framework of this examination,it was found that wave runup is affected by median sediment size,significant wave height,and foreshore beach slope.Coastal engineers and managers can utilize these findings to design more resilient coastal structures and evaluate the risks posed by coastal hazards.To improve forecast accuracy,the research stressed feature selection and model complexity management.This research proves machine learning algorithms can predict wave runup,aiding coastal engineering and management.These models help build coastal infrastructure and predict coastal hazards.展开更多
Coastal zones are transition zones between the land and sea,characterised by unique coastal ecosystems and natural resources,making them the focal point of human activities.Vulnerability assessments have been carried ...Coastal zones are transition zones between the land and sea,characterised by unique coastal ecosystems and natural resources,making them the focal point of human activities.Vulnerability assessments have been carried out along several coastal zones across the world.These assessments help coastal scientists,engineers,and policymakers prepare plans and devise mitigation measures to safeguard the environment and coastal population against climate change and coastal hazard impacts.The present study evaluates the vulnerability of the Kasaragod coast in Kerala,the west coast of India,due to sea-level rise.Eleven variables,viz.relative sea-level change,mean significant wave height,tidal range,geomorphology,shoreline change rate,regional elevation,coastal slope,population,road/railway networks,tourist sites and land use/land cover are considered in the estimation of the Coastal Vulnerability Index(CVI).The resulting CVI values were categorized into low,moderate,high and very high vulnerability classes.Based on this classification,41.33%of the Kasaragod sub-district and 13.26%of the Hosdurg sub-district fall under the‘very high’vulnerability category.A significant decrease in vulnerability was observed along the Kasaragod sub-district when socioeconomic variables were excluded from the CVI calculation.However,in the Hosdurg sub-district exclusion of the socioeconomic variables led to increased vulnerability along the coast.The vulnerability maps developed in this study provide a crucial tool for identifying highly vulnerable coastal stretches and guiding effective strategies to safeguard the Kasaragod coast and its communities.展开更多
Dark carbon fixation(DCF)is an integral component of the global carbon sink.However,quantitative data on its contribution to total carbon fixation in estuaries are scarce,and factors driving DCF remain under explorati...Dark carbon fixation(DCF)is an integral component of the global carbon sink.However,quantitative data on its contribution to total carbon fixation in estuaries are scarce,and factors driving DCF remain under exploration.In this study,radio-14C labeling and molecular techniques were employed to investigate the temporal-spatial distribution of DCF and photosynthesis rates in the Yangtze Estuary and its adjacent coastal areas(YEA),along with the potential microorganisms involved.DCF rates ranged from 0.17 to 3.79μmol C L^(−1) h^(−1) in the YEA,accounting for 15.4-97.7%of integrated total daily carbon fixation,suggesting the large variability in both DCF rates and their contributions to the carbon sink.An estimate based on 15NH4Cl labeling experiments revealed that the contribution of DCF by ammonia-oxidizing microorganisms was low(<3.97%)in surface waters of the YEA.Bacteria bearing the cbbL-IA&IC gene were the potential essential contributors to DCF,while eukaryotic phytoplankton harboring the cbbL-ID gene may also contribute to DCF through light-independentβ-carboxylation.DCF rates were mainly influenced by nutrients,particulate organic carbon,and salinity,which affect microbial abundance.Our findings underscore the importance and variability of the DCF process in human-impacted estuarine and coastal waters,contributing to a better understanding of microbial carbon fixation processes and their potential mechanisms.展开更多
The Baros coastal area in Yogyakarta,a mangrove conservation and ecotourism site,experiences high accumulation of anthropogenic marine debris(AMD)due to its location at the Opak River estuary.In addition,the presence ...The Baros coastal area in Yogyakarta,a mangrove conservation and ecotourism site,experiences high accumulation of anthropogenic marine debris(AMD)due to its location at the Opak River estuary.In addition,the presence of mangroves can trap debris carried by river flow,causing structural changes and a decrease in the function of the mangrove ecosystem.Therefore,it is necessary to analyze anthropogenic marine debris in mangrove areas as an integrated handling effort,both in terms of policy,control,and implementation.This study assesses mangrove habitat characteristics,AMD distribution,and environmental quality using the Clean Coast Index(CCI)and Hazardous Items Index(HII).The results showed that the characteristics of mangrove habitat,consisting of landward and middle zones,are freshwater/tasteless since they are only submerged during high tide conditions.Meanwhile,the seaward zone is brackish water since it is submerged all the time.The substrate of the landward zone consists of sand and clay,whilst the middle and seaward zones are predominantly composed of sand.Furthermore,our results indicate that macro debris(96%)and plastic waste(76%)dominate the area,with 83%of the study area classified as‘very dirty’and 50%under Class IV for hazardous debris,the mangrove ecosystem is at significant risk.The presence of sharp debris poses significant risks to ecosystem health.Given the critical AMD levels,urgent intervention is necessary to prevent further degradation of the mangrove ecosystem.展开更多
A large-scale sand ridge group is distributed in the central Jiangsu coastal area,and a deposition muddy sea bank was developed in the nearshore area.Quantitative monitoring of coastline changes is of great significan...A large-scale sand ridge group is distributed in the central Jiangsu coastal area,and a deposition muddy sea bank was developed in the nearshore area.Quantitative monitoring of coastline changes is of great significance for tidal beach development and protection.The shorelines of the central coast of Jiangsu within six periods(1973-2018)were extracted in this study,and their length changes over the years were analyzed.The Digital Shoreline Analysis System(DSAS)was employed to generate a cross section perpendicular to the baseline and calculate the linear regression rate(LRR)of the shoreline,changes in end point rate(EPR),and net shoreline movement(NSM),based on which the shoreline change features were analyzed.The DSAS results indicated that the shorelines in the study area maintained fluctuating growth and presented a continuous advancing trend towards the sea.From the changes in shoreline evolution distance during 1973-2018,the advancing shorelines in the study area accounted for over 50%of the total shorelines and presented first rising and then declining trends with the period of 2003-2013 taken as the time boundary.The average shoreline change rate was 207 m/year,and the periods with the highest change degrees were 1983-1993 and 1993-2013.The shoreline change tended to be stable during 2013-2018,and only a few estuaries and ports underwent obvious erosion and sedimentation.展开更多
Land clearing,river impoundments,and other human modifications to the upland landscape and within estuarine systems can drive coastal change at local to regional scales.However,as compared with mid-latitude coasts,the...Land clearing,river impoundments,and other human modifications to the upland landscape and within estuarine systems can drive coastal change at local to regional scales.However,as compared with mid-latitude coasts,the impacts of human modifications along sediment-starved formerly glaciated coastal landscapes are relatively understudied.To address this gap,we present a late-Holocene record of changing sediment accumulation rates and sediment sources from sediment cores collected across a tidal flat in the Merrimack River estuary(Mass.,USA).We pair sedimentology,geochronology,bulk-and stable-isotope organic geochemistry,and hydrodynamic simulations with historical data to evaluate human and natural impacts on coastal sediment fluxes.During the 17th to 19th centuries,accumulation rates increased by an order of magnitude in the central tidal flat,likely in response to enhanced delivery of terrestrial sediment resulting from upland deforestation.However,the overall increase in accumulation(0.56–2.6 mm/year)within the estuary is subtle and spatially variable across the tidal flats because of coincident anthropogenic land clearing and dam building,upland sediment storage,and estuarine hydrodynamics.This study provides insight into the response of formerly glaciated fluvialcoastal systems to human modifications,and underscores the role of estuarine environmental conditions in modifying upland signals of land-use change.展开更多
Cephalopods contribute to the food security of coastal communities in the Philippines.Despite their importance,the role of cephalopods in local food security remains relatively underexplored,posing challenges for effe...Cephalopods contribute to the food security of coastal communities in the Philippines.Despite their importance,the role of cephalopods in local food security remains relatively underexplored,posing challenges for effective coastal resource management.This study applies a modified food security framework(FAO 2006)to analyze the four dimensions of food security—availability,access,utilization,and stability—in the cephalopod fishery of Malalison Island,Philippines.The island's local management system includes a Territorial Use Rights for Fisheries scheme integrated with a Marine Protected Area,operating under a community-based management.Data was collected in 36 semi-structured interviews and during a focus group discussion with ten fishers featuring a participatory mapping activity.Findings reveal that while cephalopods remain a stable food source,cephalopods are perceived by fishers to be threatened by climate change,unsustainable fishing practices,illegal activities,as well as resource and physical constraints among fishers.To ensure cephalopods as a source of food security,future research and coastal management efforts should prioritize biological surveys and catch landing data collection,together with enhanced enforcement and community engagement.展开更多
To better understand the alteration of the estuarine circulation caused by estuarine dams,four major Korean estuaries were classified by using the Hansen and Rattray stratification–circulation classification scheme.T...To better understand the alteration of the estuarine circulation caused by estuarine dams,four major Korean estuaries were classified by using the Hansen and Rattray stratification–circulation classification scheme.The stratification and circulation parameters were calculated for both discharge and no-discharge periods from the tidally averaged salinity and velocity data obtained from these four Korean estuaries.The estuarine types of the altered Korean estuaries were compared with the previous results for natural estuaries in other countries of similar magnitude in tidal range,water depth,and discharge.This comparison revealed that the estuarine types of the altered Korean estuaries have been shifted from a partially mixed to a well-mixed type(Nakdong River Estuary),from a partially mixed to a coastal bay or a fjord type(Yeongsan River Estuary),and from a well-mixed to a well-mixed type with less tidal modulation(Geum River Estuary).The controlling factors that determined the type in natural estuaries were tide,discharge,and water depth,whereas for altered estuaries,they were the controlled river discharge and water depth.The different estuarine dam gate types with their different modes of operation(surface or bottom discharge)played an important role in the mixing and circulation of the altered estuaries.展开更多
The impacts of climate change on marine fisheries are becoming increasingly evident;however,climate resilient fisheries management and policy making continues to be challenging.In the Arabian Peninsula Region(APR),pro...The impacts of climate change on marine fisheries are becoming increasingly evident;however,climate resilient fisheries management and policy making continues to be challenging.In the Arabian Peninsula Region(APR),productivity of the marine and coastal fisheries is largely impacted by climate change.The present study provides perspectives of the existing fisheries management plans of the APR with special emphasis on the Sultanate of Oman(SO)by conducting a comprehensive literature survey that includes primary research articles,academic theses,reports,governmental decisions and legislations and reputable websites.The study proposes future climate-adaptive management strategies for APR and SO,emphasizing the risk assessments,stakeholder collaboration by taking a transboundary approach.Fisheries management in the APR currently faces challenges of overfishing,habitat degradation,and climate change impacts,with each country employing unique approaches;regional cooperation and sharing best practices are deemed essential for long-term sustainability.Fisheries management in the SO,a critical part of the country's economy,includes measures such as licensing and seasonal closures;however,a climate-resilient framework for pelagic fisheries is lacking,which is creating an uncertainty in fisheries management the face of ongoing climate change.Effective climate-adaptive fisheries management in the SO necessitates risk assessments,stakeholder engagement,and cross-border collaborations.The APR as a whole requires integrated short-and long-term strategies for addressing climate change impacts on marine ecosystems and fisheries,with a focus on flexibility and local participation.The study recommends ecosystem-based fisheries management,which incorporates both biotic and abiotic elements,as well as regional evaluations and co-management solutions to mitigate the effects of climate change.展开更多
Using numerical modelling,we study changes in tidal dynamics in Daya Bay(DYB)between 1989 and 2014.During this period,a total water area of 30 km^(2)was reclaimed and the average water depth increased by 38 cm.As DYB ...Using numerical modelling,we study changes in tidal dynamics in Daya Bay(DYB)between 1989 and 2014.During this period,a total water area of 30 km^(2)was reclaimed and the average water depth increased by 38 cm.As DYB is a sexta-diurnal tidal resonant bay,the sexta-diurnal tides respond differently to the coastline and bathymetry changes than other tides.Taking K_(1),M_(2),M_(4),and M_(6)as examples,model results show a decrease in tidal elevation amplitude,tidal current magnitude,and tidal energy flux for K1,M_(2),and M_(4)tides.For the M_(6)tide,however,the model predicted an increase in tidal elevation amplitude,tidal current magnitude in some parts of the bay,and the tidal energy flowing into the bay.Land reclamation leads to the enhancement of sexta-diurnal tidal resonance and thus the magnitude of the M_(6)tide.Furthermore,due to the magnification of M_(6),tidal duration asymmetry in DYB changed from ebb-dominance to flood-dominance,and water exchange became much more active.Therefore,owing to the sexta-diurnal tidal resonance,the impact of human activities on tidal dynamics in DYB is different from that in previously reported semi-enclosed bays where large-scale land reclamation has been carried out.展开更多
The massive Qingcaosha Reservoir(QCSR)is located in the Changjiang Estuary along the northwest coast of Changxing Island.The reservoir significantly narrowed the upper reaches of the North Channel and deepened the cha...The massive Qingcaosha Reservoir(QCSR)is located in the Changjiang Estuary along the northwest coast of Changxing Island.The reservoir significantly narrowed the upper reaches of the North Channel and deepened the channel near the reservoir.These topographical changes inevitably influenced hydrodynamic processes and saltwater intrusion in the estuary.A well-validated model was employed to investigate the influence of the QCSR on saltwater intrusion in the Changjiang Estuary.The model results showed that the narrowed upper reaches of the North Channel decreased the water diversion ratio and thus increased salinity in the North Channel.During the moderate tide after neap tide,the salinity decreased at the water intake of the QCSR because saltwater intrusion was obstructed at flood slack at the surface,while the salinity increase during the moderate tide after spring tide was mainly due to the intensified saltwater intrusion during spring tide.The deepening of the channel near the QCSR resulted in an increased water diversion ratio,and the salinity in the Eastern Chongming Shoal decreased by more than 0.5 psu during spring tide;however,the saltwater intrusion was enhanced due to the strengthened baroclinic force,which is proportional to the water depth.During neap tide,the salinity in the entire North Channel decreased because of a 1.4%increase in the water diversion ratio of the North Channel and the relatively weak tide.展开更多
The growing push for open data resulted in an abundance of data for coastal researchers,which can lead to problems for individual researchers related to data discoverability.One solution is to explicitly develop servi...The growing push for open data resulted in an abundance of data for coastal researchers,which can lead to problems for individual researchers related to data discoverability.One solution is to explicitly develop services for coastal researchers to help curate data for discovery,hosting discussions around reuse,community building,and finding collaborators.To develop the idea of a coastal data curation service,we investigate aspects of the UNESCO International Coastal Atlas Network member sites that could be used to build a curation service.We develop a minimal example of a coastal data curation service,deploy this as a website,and describe the next steps to move beyond the prototype phase.We envision a coastal data curation service as a way to cultivate a community focused on coastal data discovery and reuse.展开更多
Since 1958,there have been significant changes in the Yangtze River estuary.Due to extensive reclamation and con-struction of ports and channels,the water area has drastically decreased,resulting in corresponding chan...Since 1958,there have been significant changes in the Yangtze River estuary.Due to extensive reclamation and con-struction of ports and channels,the water area has drastically decreased,resulting in corresponding changes in hydrodynamics and riverbeds at the mouth of the river.According to the analysis of measured topographic data and Delft3D-FLOW model for seven typical historical periods since 1958 at the Yangtze River Estuary,this study investigates the characteristics of riverbed evolution and tidal flow dynamics.From 1958 to 2019,driven by strong human activities,the total area of the Yangtze River Estuary decreased from 2084km^(2)to 1403km^(2),with a decrease of 32.7%,while the total volume of the corresponding river channel changed slightly and remained stable.Com-pared with 1958,the volume of the Yangtze River Estuary in 2019 only increased by 345 million m^(3),with an increase of about 4.1%.The tidal dynamic change of the Yangtze Estuary is closely related to the riverbed evolution of each reach,which not only shapes the estuary landform,but also is affected by the riverbed evolution.Tidal level,tidal range and water area change are closely related.With the decrease of water area in the Yangtze River Estuary,tidal range tends to increase.Tidal prism change is closely related to channel volume.In the past 60 years,the tidal vol-ume at the mouth of the Yangtze River has decreased by 8%.The research findings will provide technical support for enhancing flood control and tide resistance measures at the Yangtze River Estuary,as well as formulating compre-hensive management plans for estuaries,contributing to the protection and sustainable development of the Yangtze River Estuary.展开更多
Salt marshes are key coastal ecosystems that provide habitats for wildlife,including invertebrates,fishes,and birds.They provide ecosystem services such as protection from storm surges and waves,attenuation of floodin...Salt marshes are key coastal ecosystems that provide habitats for wildlife,including invertebrates,fishes,and birds.They provide ecosystem services such as protection from storm surges and waves,attenuation of flooding,sequestration of pollutants(e.g.,blue carbon),and nutrient removal.They are currently under great threat from sea level rise(SLR).We collected information about trends in the horizontal extent(acreage)of New Jersey salt marshes and recent elevation changes compared with the current local rate of SLR in New Jersey,which is between 5 and 6 mm year^(-1).We found pervasive,although variable,rates of marsh loss that resulted from both anthropogenic disturbance as well as edge erosion and interior ponding expected from SLR.Elevation trends suggest that the current rates of SLR exceed most marsh elevation gains,although some Phragmites-dominated marshes keep pace with SLR.Four potential remedies to address current coastal trends of marsh loss were described in the context of New Jersey’s regulatory and management environment:protection of marsh inland migration pathways,altered management of Phragmites,thin layer sediment placement,and living shoreline installations.Proactive steps are necessary if coastal wetland ecosystems are to be maintained over the next few decades.展开更多
Coastal lagoons are highly susceptible to the impacts of climate change.In lagoons of the Global South development challenges and growing coastal populations compound climate stressors to create complex inter-connecte...Coastal lagoons are highly susceptible to the impacts of climate change.In lagoons of the Global South development challenges and growing coastal populations compound climate stressors to create complex inter-connected problems that cross social,economic and environmental boundaries.The successful governance of lagoons thus requires multidimensional approaches that combine disciplines and incorporate multiple knowledges.A stakeholder informed management framework was developed for West African lagoons using a transdisciplinary and participatory approach.A network of researchers from across the region,collectively known as the Resilient Lagoon Network,facilitated participatory platforms for stakeholders to share their experiences of the stressors facing lagoons and their management.Participants were from academia,government organisations,NGOs,traditional authorities and coastal lagoon communities.The information acquired enabled an understanding and relative importance of the challenges facing lagoons as well as what constituted good management practice and an appreciation for the breadth of lagoon stakeholders.From this information a framework was created comprising three strands that outlined the“what,how and who”of sustainable lagoon management.The“what”consists of a series of social,economic,environmental and governance indicators,linked to the sustainable development goals,that provide a checklist for lagoon sustainability.The“how”outlines tenets of good governance with an emphasis on equity,participation,cooperation and open communication.The“who”maps the range of possible lagoon stakeholders.The framework has been sense tested with lagoon practitioners and made available across the region.Although based on the experience of West African lagoon stakeholders,it could be used to inform the management of lagoons across the Global South.展开更多
The dynamic response of marine sediment from the Yellow River under extreme sea conditions is attracting increasing academic and engineering attention because of the high occurrence frequency of geologic hazards.To si...The dynamic response of marine sediment from the Yellow River under extreme sea conditions is attracting increasing academic and engineering attention because of the high occurrence frequency of geologic hazards.To simulate the dynamic response process of sediment samples under waves with a 50 year recurrence interval,we collected undisturbed sediment samples from six sites on the intertidal flats of the Yellow River Delta and performed dynamic triaxial experiments to analyze the pore-water pressure and liquefaction process.The empirical patterns of pore-water pressure generation and ranges of sediment parameters were determined,and the factors affecting sediment liquefaction were discussed.Under the cyclic loading of waves with a 50 year recurrence interval,the pore pressure response of sediments at a depth of 4 m could be generalized into three stages:rapid growth,slow growth,and stable maintenance.Moreover,the build-up of pore-water pressure was effectively represented by a logarithmic growth model.The liquefaction characteristics of sediment in the Yellow River Delta were more related to its plasticity index,mean particle size,and clay,silt,and sand contents,as well as the sedimentary history.These factors should be considered in the development of disaster assessment models in coastal environments of the Yellow River Delta.展开更多
In the present paper,tides in the port of Vancouver Harbour have been investigated with a high-resolution three-dimensional hydrodynamic model based on FVCOM(Finite Volume Community Ocean Model).The model was evaluate...In the present paper,tides in the port of Vancouver Harbour have been investigated with a high-resolution three-dimensional hydrodynamic model based on FVCOM(Finite Volume Community Ocean Model).The model was evaluated against field observations including tidal elevations and tidal currents,and the evaluation showed that the model was in good agreement with the observational data.Using the model,we first investigated the horizontal distributions of tides,tidal currents,and tidally induced residual circulation,and then investigated the tidal asymmetry and dynamic mechanisms of tidal flows in the harbour.The tidal residual circulation shows a strong spatial pattern,which is associated with the local coastlines and variation of topography.The tidal asymmetry in the harbour is caused by different mechanisms,not only including the traditional factors,such as residual flows,the interaction between M_(2)and its overtide M_(4),but also the interaction of principal astronomical tides of O_(1),K_(1),and M_(2).The momentum balance is dominated by terms of the advection and the pressure gradient in First Narrows and Second Narrows,whereas terms of the local acceleration and the Coriolis are also important in the central harbour.The spatial variations of the momentum terms are strongly associated with the local changes in coastline and topography.展开更多
The typhoon process has a significant influence on the distribution of heavy metals in sediments.Based on the heavy metal(V,Cr,Co,Ni,Cu,Zn,Pb,and Mn)contents in surface sediments collected under normal conditions and ...The typhoon process has a significant influence on the distribution of heavy metals in sediments.Based on the heavy metal(V,Cr,Co,Ni,Cu,Zn,Pb,and Mn)contents in surface sediments collected under normal conditions and post-typhoon Matmo in Quanzhou Bay in 2014,the distributions,sources,and impacts of typhoon processes on heavy metals and pollution conditions were studied and discussed.The results showed that the heavy metals can be divided into two categories:Class I metals(Cu,Zn,Pb,and Mn)were mainly distributed in the estuary and significantly increased after the typhoon,and Class II metals(V,Cr,Co,and Ni)were distributed in the coastal intertidal zone and estuary and remained unchanged or decreased after the typhoon.The heavy metal assessment showed that heavy metal pollution in Quanzhou Bay was serious and tended to increase after the typhoon.The increased metal supply and enhanced riverine and tidal hydrodynamics after the typhoon may be the main factors influencing the variations in heavy metal content and distribution.This study provided a basis for the accurate evaluation and scientific management of heavy metal pollution caused by typhoon processes in Quanzhou Bay.展开更多
The western Bay of Bengal is particularly susceptible to the harmful impacts of increasing coastal pollution,as coastal population and urban development are occurring at unprecedented rates.The rapid urbanization and ...The western Bay of Bengal is particularly susceptible to the harmful impacts of increasing coastal pollution,as coastal population and urban development are occurring at unprecedented rates.The rapid urbanization and industrialization along the east coast of India coupled with the transfer of contaminants into the Bay of Bengal through riverine systems,causing a direct impact on marine ecosystems.In the present study,an attempt has been made to understand the heavy metal distribution on shelf sediments in the western part of the Bay of Bengal to infer their source,processes,and historical changes in marine pollution.Three short sediment core samples were collected and analysed for sediment texture,organic matter,and heavy metals.Cores 1 and 2 contain a high amount of sand content,representing shallow marine with moderate to high-energy conditions,and were deposited at a recent time.Core 3 was dominated by muddy sand to sandy mud,which denotes calm sedimentation without any turbulence,and these sediments were deposited under relatively low-energy conditions.The higher concentration of organic matter in the top layers of the core indicates both marine and terrestrial input.The heavy metal contents show quite heterogeneous and variable distributions from one element to another and from one core to another.The calculated pollution indices such as Contamination Factor(CF),and Geoaccumulation Index(Igeo)and Pollution Load Index(PLI)values indicate that all the core sub-samples are severely enriched and highly polluted by Cd and moderately polluted by Pb.The increased heavy metal concentration in the upper portion of the sediment cores and moderate to considerable ecological risks indicate that these metals have been deposited in the study area for the past few decades.展开更多
基金funded by the National Natural Science Foundation of China(41776052)the Nanjing Geological Survey Center of China Geological Survey(NJZX-W-2019-099).
文摘The Anthropocene is being considered as a new geological epoch because human activities now rival geological forces to radically alter the natural state and functioning of the Earth system,producing its own distinctive sedimentary records(Waters et al.2016).These changes of varied magnitude can be traced over different spatiotemporal scales.
文摘The present study uses nine machine learning(ML)methods to predict wave runup in an innovative and comprehensive methodology.Unlike previous investigations,which often limited the factors considered when applying ML methodologies to predict wave runup,this approach takes a holistic perspective.The analysis takes into account a comprehensive range of crucial coastal parameters,including the 2%exceedance value for runup,setup,total swash excursion,incident swash,infragravity swash,significant wave height,peak wave period,foreshore beach slope,and median sediment size.Model performance,interpretability,and practicality were assessed.The findings from this study showes that linear models,while valuable in many applications,proved insufficient in grasping the complexity of this dataset.On the other hand,we found that non-linear models are essential for achieving accurate wave runup predictions,underscoring their significance in the context of the research.Within the framework of this examination,it was found that wave runup is affected by median sediment size,significant wave height,and foreshore beach slope.Coastal engineers and managers can utilize these findings to design more resilient coastal structures and evaluate the risks posed by coastal hazards.To improve forecast accuracy,the research stressed feature selection and model complexity management.This research proves machine learning algorithms can predict wave runup,aiding coastal engineering and management.These models help build coastal infrastructure and predict coastal hazards.
文摘Coastal zones are transition zones between the land and sea,characterised by unique coastal ecosystems and natural resources,making them the focal point of human activities.Vulnerability assessments have been carried out along several coastal zones across the world.These assessments help coastal scientists,engineers,and policymakers prepare plans and devise mitigation measures to safeguard the environment and coastal population against climate change and coastal hazard impacts.The present study evaluates the vulnerability of the Kasaragod coast in Kerala,the west coast of India,due to sea-level rise.Eleven variables,viz.relative sea-level change,mean significant wave height,tidal range,geomorphology,shoreline change rate,regional elevation,coastal slope,population,road/railway networks,tourist sites and land use/land cover are considered in the estimation of the Coastal Vulnerability Index(CVI).The resulting CVI values were categorized into low,moderate,high and very high vulnerability classes.Based on this classification,41.33%of the Kasaragod sub-district and 13.26%of the Hosdurg sub-district fall under the‘very high’vulnerability category.A significant decrease in vulnerability was observed along the Kasaragod sub-district when socioeconomic variables were excluded from the CVI calculation.However,in the Hosdurg sub-district exclusion of the socioeconomic variables led to increased vulnerability along the coast.The vulnerability maps developed in this study provide a crucial tool for identifying highly vulnerable coastal stretches and guiding effective strategies to safeguard the Kasaragod coast and its communities.
基金supported by the National Natural Science Foundation of China(42030411 and 41971125)the Chinese National Key Programs for Fundamental Research and Development(2023YFC3709005)the National Science Foundation for Distinguished Young Scholars(41725002).
文摘Dark carbon fixation(DCF)is an integral component of the global carbon sink.However,quantitative data on its contribution to total carbon fixation in estuaries are scarce,and factors driving DCF remain under exploration.In this study,radio-14C labeling and molecular techniques were employed to investigate the temporal-spatial distribution of DCF and photosynthesis rates in the Yangtze Estuary and its adjacent coastal areas(YEA),along with the potential microorganisms involved.DCF rates ranged from 0.17 to 3.79μmol C L^(−1) h^(−1) in the YEA,accounting for 15.4-97.7%of integrated total daily carbon fixation,suggesting the large variability in both DCF rates and their contributions to the carbon sink.An estimate based on 15NH4Cl labeling experiments revealed that the contribution of DCF by ammonia-oxidizing microorganisms was low(<3.97%)in surface waters of the YEA.Bacteria bearing the cbbL-IA&IC gene were the potential essential contributors to DCF,while eukaryotic phytoplankton harboring the cbbL-ID gene may also contribute to DCF through light-independentβ-carboxylation.DCF rates were mainly influenced by nutrients,particulate organic carbon,and salinity,which affect microbial abundance.Our findings underscore the importance and variability of the DCF process in human-impacted estuarine and coastal waters,contributing to a better understanding of microbial carbon fixation processes and their potential mechanisms.
文摘The Baros coastal area in Yogyakarta,a mangrove conservation and ecotourism site,experiences high accumulation of anthropogenic marine debris(AMD)due to its location at the Opak River estuary.In addition,the presence of mangroves can trap debris carried by river flow,causing structural changes and a decrease in the function of the mangrove ecosystem.Therefore,it is necessary to analyze anthropogenic marine debris in mangrove areas as an integrated handling effort,both in terms of policy,control,and implementation.This study assesses mangrove habitat characteristics,AMD distribution,and environmental quality using the Clean Coast Index(CCI)and Hazardous Items Index(HII).The results showed that the characteristics of mangrove habitat,consisting of landward and middle zones,are freshwater/tasteless since they are only submerged during high tide conditions.Meanwhile,the seaward zone is brackish water since it is submerged all the time.The substrate of the landward zone consists of sand and clay,whilst the middle and seaward zones are predominantly composed of sand.Furthermore,our results indicate that macro debris(96%)and plastic waste(76%)dominate the area,with 83%of the study area classified as‘very dirty’and 50%under Class IV for hazardous debris,the mangrove ecosystem is at significant risk.The presence of sharp debris poses significant risks to ecosystem health.Given the critical AMD levels,urgent intervention is necessary to prevent further degradation of the mangrove ecosystem.
基金support from the Jiangsu Bureau of Surveying and Mapping Geographic Information,National Earth System Science Data Sharing Infrastructure,and National Science and Technology Infrastructure of China(http://nnu.geodata.cn)supported by funding from the NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(No.U1609203)and the National Natural Science Foundation of China(No.41771447).
文摘A large-scale sand ridge group is distributed in the central Jiangsu coastal area,and a deposition muddy sea bank was developed in the nearshore area.Quantitative monitoring of coastline changes is of great significance for tidal beach development and protection.The shorelines of the central coast of Jiangsu within six periods(1973-2018)were extracted in this study,and their length changes over the years were analyzed.The Digital Shoreline Analysis System(DSAS)was employed to generate a cross section perpendicular to the baseline and calculate the linear regression rate(LRR)of the shoreline,changes in end point rate(EPR),and net shoreline movement(NSM),based on which the shoreline change features were analyzed.The DSAS results indicated that the shorelines in the study area maintained fluctuating growth and presented a continuous advancing trend towards the sea.From the changes in shoreline evolution distance during 1973-2018,the advancing shorelines in the study area accounted for over 50%of the total shorelines and presented first rising and then declining trends with the period of 2003-2013 taken as the time boundary.The average shoreline change rate was 207 m/year,and the periods with the highest change degrees were 1983-1993 and 1993-2013.The shoreline change tended to be stable during 2013-2018,and only a few estuaries and ports underwent obvious erosion and sedimentation.
基金funded by the National Science Foundation Coastal SEES(award No.OCE 1325430)the Charles Center at William&Mary,and the Southeastern Section of the Geological Society of America+1 种基金The Virginia Institute of Marine Science(VIMS)National Science Foundation REU Program(award No.OCE 1062882)a VIMS Short Trust GK-12 Fellowship supported JLS.
文摘Land clearing,river impoundments,and other human modifications to the upland landscape and within estuarine systems can drive coastal change at local to regional scales.However,as compared with mid-latitude coasts,the impacts of human modifications along sediment-starved formerly glaciated coastal landscapes are relatively understudied.To address this gap,we present a late-Holocene record of changing sediment accumulation rates and sediment sources from sediment cores collected across a tidal flat in the Merrimack River estuary(Mass.,USA).We pair sedimentology,geochronology,bulk-and stable-isotope organic geochemistry,and hydrodynamic simulations with historical data to evaluate human and natural impacts on coastal sediment fluxes.During the 17th to 19th centuries,accumulation rates increased by an order of magnitude in the central tidal flat,likely in response to enhanced delivery of terrestrial sediment resulting from upland deforestation.However,the overall increase in accumulation(0.56–2.6 mm/year)within the estuary is subtle and spatially variable across the tidal flats because of coincident anthropogenic land clearing and dam building,upland sediment storage,and estuarine hydrodynamics.This study provides insight into the response of formerly glaciated fluvialcoastal systems to human modifications,and underscores the role of estuarine environmental conditions in modifying upland signals of land-use change.
文摘Cephalopods contribute to the food security of coastal communities in the Philippines.Despite their importance,the role of cephalopods in local food security remains relatively underexplored,posing challenges for effective coastal resource management.This study applies a modified food security framework(FAO 2006)to analyze the four dimensions of food security—availability,access,utilization,and stability—in the cephalopod fishery of Malalison Island,Philippines.The island's local management system includes a Territorial Use Rights for Fisheries scheme integrated with a Marine Protected Area,operating under a community-based management.Data was collected in 36 semi-structured interviews and during a focus group discussion with ten fishers featuring a participatory mapping activity.Findings reveal that while cephalopods remain a stable food source,cephalopods are perceived by fishers to be threatened by climate change,unsustainable fishing practices,illegal activities,as well as resource and physical constraints among fishers.To ensure cephalopods as a source of food security,future research and coastal management efforts should prioritize biological surveys and catch landing data collection,together with enhanced enforcement and community engagement.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2017R1D1A1B05033162).
文摘To better understand the alteration of the estuarine circulation caused by estuarine dams,four major Korean estuaries were classified by using the Hansen and Rattray stratification–circulation classification scheme.The stratification and circulation parameters were calculated for both discharge and no-discharge periods from the tidally averaged salinity and velocity data obtained from these four Korean estuaries.The estuarine types of the altered Korean estuaries were compared with the previous results for natural estuaries in other countries of similar magnitude in tidal range,water depth,and discharge.This comparison revealed that the estuarine types of the altered Korean estuaries have been shifted from a partially mixed to a well-mixed type(Nakdong River Estuary),from a partially mixed to a coastal bay or a fjord type(Yeongsan River Estuary),and from a well-mixed to a well-mixed type with less tidal modulation(Geum River Estuary).The controlling factors that determined the type in natural estuaries were tide,discharge,and water depth,whereas for altered estuaries,they were the controlled river discharge and water depth.The different estuarine dam gate types with their different modes of operation(surface or bottom discharge)played an important role in the mixing and circulation of the altered estuaries.
文摘The impacts of climate change on marine fisheries are becoming increasingly evident;however,climate resilient fisheries management and policy making continues to be challenging.In the Arabian Peninsula Region(APR),productivity of the marine and coastal fisheries is largely impacted by climate change.The present study provides perspectives of the existing fisheries management plans of the APR with special emphasis on the Sultanate of Oman(SO)by conducting a comprehensive literature survey that includes primary research articles,academic theses,reports,governmental decisions and legislations and reputable websites.The study proposes future climate-adaptive management strategies for APR and SO,emphasizing the risk assessments,stakeholder collaboration by taking a transboundary approach.Fisheries management in the APR currently faces challenges of overfishing,habitat degradation,and climate change impacts,with each country employing unique approaches;regional cooperation and sharing best practices are deemed essential for long-term sustainability.Fisheries management in the SO,a critical part of the country's economy,includes measures such as licensing and seasonal closures;however,a climate-resilient framework for pelagic fisheries is lacking,which is creating an uncertainty in fisheries management the face of ongoing climate change.Effective climate-adaptive fisheries management in the SO necessitates risk assessments,stakeholder engagement,and cross-border collaborations.The APR as a whole requires integrated short-and long-term strategies for addressing climate change impacts on marine ecosystems and fisheries,with a focus on flexibility and local participation.The study recommends ecosystem-based fisheries management,which incorporates both biotic and abiotic elements,as well as regional evaluations and co-management solutions to mitigate the effects of climate change.
基金supported by the National Natural Science Foundation of China(Grant No.41806132)the Ministry of Science and Technology of China(Grant No.2015CB452905).
文摘Using numerical modelling,we study changes in tidal dynamics in Daya Bay(DYB)between 1989 and 2014.During this period,a total water area of 30 km^(2)was reclaimed and the average water depth increased by 38 cm.As DYB is a sexta-diurnal tidal resonant bay,the sexta-diurnal tides respond differently to the coastline and bathymetry changes than other tides.Taking K_(1),M_(2),M_(4),and M_(6)as examples,model results show a decrease in tidal elevation amplitude,tidal current magnitude,and tidal energy flux for K1,M_(2),and M_(4)tides.For the M_(6)tide,however,the model predicted an increase in tidal elevation amplitude,tidal current magnitude in some parts of the bay,and the tidal energy flowing into the bay.Land reclamation leads to the enhancement of sexta-diurnal tidal resonance and thus the magnitude of the M_(6)tide.Furthermore,due to the magnification of M_(6),tidal duration asymmetry in DYB changed from ebb-dominance to flood-dominance,and water exchange became much more active.Therefore,owing to the sexta-diurnal tidal resonance,the impact of human activities on tidal dynamics in DYB is different from that in previously reported semi-enclosed bays where large-scale land reclamation has been carried out.
基金supported by the National Natural Science Foundation of China(41676083).
文摘The massive Qingcaosha Reservoir(QCSR)is located in the Changjiang Estuary along the northwest coast of Changxing Island.The reservoir significantly narrowed the upper reaches of the North Channel and deepened the channel near the reservoir.These topographical changes inevitably influenced hydrodynamic processes and saltwater intrusion in the estuary.A well-validated model was employed to investigate the influence of the QCSR on saltwater intrusion in the Changjiang Estuary.The model results showed that the narrowed upper reaches of the North Channel decreased the water diversion ratio and thus increased salinity in the North Channel.During the moderate tide after neap tide,the salinity decreased at the water intake of the QCSR because saltwater intrusion was obstructed at flood slack at the surface,while the salinity increase during the moderate tide after spring tide was mainly due to the intensified saltwater intrusion during spring tide.The deepening of the channel near the QCSR resulted in an increased water diversion ratio,and the salinity in the Eastern Chongming Shoal decreased by more than 0.5 psu during spring tide;however,the saltwater intrusion was enhanced due to the strengthened baroclinic force,which is proportional to the water depth.During neap tide,the salinity in the entire North Channel decreased because of a 1.4%increase in the water diversion ratio of the North Channel and the relatively weak tide.
基金support from US National Science Foundation(1939954,1953412 to E.B.G.1940006,1924670 to A.E.B.)+1 种基金a US National Science Foundation Graduate Research Fellowship(Grant No.DGE 1650115 to C.M.M.)an Early-Career Research Fellowship from the Gulf Research Program of the National Academies of Sciences,Engineering,and Medicine(to E.B.G.).
文摘The growing push for open data resulted in an abundance of data for coastal researchers,which can lead to problems for individual researchers related to data discoverability.One solution is to explicitly develop services for coastal researchers to help curate data for discovery,hosting discussions around reuse,community building,and finding collaborators.To develop the idea of a coastal data curation service,we investigate aspects of the UNESCO International Coastal Atlas Network member sites that could be used to build a curation service.We develop a minimal example of a coastal data curation service,deploy this as a website,and describe the next steps to move beyond the prototype phase.We envision a coastal data curation service as a way to cultivate a community focused on coastal data discovery and reuse.
基金funded by the National Key R&D Program of China(2023YFC3208500).
文摘Since 1958,there have been significant changes in the Yangtze River estuary.Due to extensive reclamation and con-struction of ports and channels,the water area has drastically decreased,resulting in corresponding changes in hydrodynamics and riverbeds at the mouth of the river.According to the analysis of measured topographic data and Delft3D-FLOW model for seven typical historical periods since 1958 at the Yangtze River Estuary,this study investigates the characteristics of riverbed evolution and tidal flow dynamics.From 1958 to 2019,driven by strong human activities,the total area of the Yangtze River Estuary decreased from 2084km^(2)to 1403km^(2),with a decrease of 32.7%,while the total volume of the corresponding river channel changed slightly and remained stable.Com-pared with 1958,the volume of the Yangtze River Estuary in 2019 only increased by 345 million m^(3),with an increase of about 4.1%.The tidal dynamic change of the Yangtze Estuary is closely related to the riverbed evolution of each reach,which not only shapes the estuary landform,but also is affected by the riverbed evolution.Tidal level,tidal range and water area change are closely related.With the decrease of water area in the Yangtze River Estuary,tidal range tends to increase.Tidal prism change is closely related to channel volume.In the past 60 years,the tidal vol-ume at the mouth of the Yangtze River has decreased by 8%.The research findings will provide technical support for enhancing flood control and tide resistance measures at the Yangtze River Estuary,as well as formulating compre-hensive management plans for estuaries,contributing to the protection and sustainable development of the Yangtze River Estuary.
文摘Salt marshes are key coastal ecosystems that provide habitats for wildlife,including invertebrates,fishes,and birds.They provide ecosystem services such as protection from storm surges and waves,attenuation of flooding,sequestration of pollutants(e.g.,blue carbon),and nutrient removal.They are currently under great threat from sea level rise(SLR).We collected information about trends in the horizontal extent(acreage)of New Jersey salt marshes and recent elevation changes compared with the current local rate of SLR in New Jersey,which is between 5 and 6 mm year^(-1).We found pervasive,although variable,rates of marsh loss that resulted from both anthropogenic disturbance as well as edge erosion and interior ponding expected from SLR.Elevation trends suggest that the current rates of SLR exceed most marsh elevation gains,although some Phragmites-dominated marshes keep pace with SLR.Four potential remedies to address current coastal trends of marsh loss were described in the context of New Jersey’s regulatory and management environment:protection of marsh inland migration pathways,altered management of Phragmites,thin layer sediment placement,and living shoreline installations.Proactive steps are necessary if coastal wetland ecosystems are to be maintained over the next few decades.
文摘Coastal lagoons are highly susceptible to the impacts of climate change.In lagoons of the Global South development challenges and growing coastal populations compound climate stressors to create complex inter-connected problems that cross social,economic and environmental boundaries.The successful governance of lagoons thus requires multidimensional approaches that combine disciplines and incorporate multiple knowledges.A stakeholder informed management framework was developed for West African lagoons using a transdisciplinary and participatory approach.A network of researchers from across the region,collectively known as the Resilient Lagoon Network,facilitated participatory platforms for stakeholders to share their experiences of the stressors facing lagoons and their management.Participants were from academia,government organisations,NGOs,traditional authorities and coastal lagoon communities.The information acquired enabled an understanding and relative importance of the challenges facing lagoons as well as what constituted good management practice and an appreciation for the breadth of lagoon stakeholders.From this information a framework was created comprising three strands that outlined the“what,how and who”of sustainable lagoon management.The“what”consists of a series of social,economic,environmental and governance indicators,linked to the sustainable development goals,that provide a checklist for lagoon sustainability.The“how”outlines tenets of good governance with an emphasis on equity,participation,cooperation and open communication.The“who”maps the range of possible lagoon stakeholders.The framework has been sense tested with lagoon practitioners and made available across the region.Although based on the experience of West African lagoon stakeholders,it could be used to inform the management of lagoons across the Global South.
基金supported by Qingdao National Laboratory for Marine Science and Technology(QNLM2016ORP0110)the National Natural Science Foundation of China(41506077 and 41877221)the Fundamental Research Funds for the Central Universities(201822013).
文摘The dynamic response of marine sediment from the Yellow River under extreme sea conditions is attracting increasing academic and engineering attention because of the high occurrence frequency of geologic hazards.To simulate the dynamic response process of sediment samples under waves with a 50 year recurrence interval,we collected undisturbed sediment samples from six sites on the intertidal flats of the Yellow River Delta and performed dynamic triaxial experiments to analyze the pore-water pressure and liquefaction process.The empirical patterns of pore-water pressure generation and ranges of sediment parameters were determined,and the factors affecting sediment liquefaction were discussed.Under the cyclic loading of waves with a 50 year recurrence interval,the pore pressure response of sediments at a depth of 4 m could be generalized into three stages:rapid growth,slow growth,and stable maintenance.Moreover,the build-up of pore-water pressure was effectively represented by a logarithmic growth model.The liquefaction characteristics of sediment in the Yellow River Delta were more related to its plasticity index,mean particle size,and clay,silt,and sand contents,as well as the sedimentary history.These factors should be considered in the development of disaster assessment models in coastal environments of the Yellow River Delta.
基金supported by the Department of Fisheries and Oceans Canada(DFO).
文摘In the present paper,tides in the port of Vancouver Harbour have been investigated with a high-resolution three-dimensional hydrodynamic model based on FVCOM(Finite Volume Community Ocean Model).The model was evaluated against field observations including tidal elevations and tidal currents,and the evaluation showed that the model was in good agreement with the observational data.Using the model,we first investigated the horizontal distributions of tides,tidal currents,and tidally induced residual circulation,and then investigated the tidal asymmetry and dynamic mechanisms of tidal flows in the harbour.The tidal residual circulation shows a strong spatial pattern,which is associated with the local coastlines and variation of topography.The tidal asymmetry in the harbour is caused by different mechanisms,not only including the traditional factors,such as residual flows,the interaction between M_(2)and its overtide M_(4),but also the interaction of principal astronomical tides of O_(1),K_(1),and M_(2).The momentum balance is dominated by terms of the advection and the pressure gradient in First Narrows and Second Narrows,whereas terms of the local acceleration and the Coriolis are also important in the central harbour.The spatial variations of the momentum terms are strongly associated with the local changes in coastline and topography.
基金supported by the Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources(Nos.TIO2015014 and TIO2014016)the National Programme on Global Change and Air-Sea Interaction(No.GASI-GEOGE-03)the National Science Foundation of China(NSFC,No.41676028).
文摘The typhoon process has a significant influence on the distribution of heavy metals in sediments.Based on the heavy metal(V,Cr,Co,Ni,Cu,Zn,Pb,and Mn)contents in surface sediments collected under normal conditions and post-typhoon Matmo in Quanzhou Bay in 2014,the distributions,sources,and impacts of typhoon processes on heavy metals and pollution conditions were studied and discussed.The results showed that the heavy metals can be divided into two categories:Class I metals(Cu,Zn,Pb,and Mn)were mainly distributed in the estuary and significantly increased after the typhoon,and Class II metals(V,Cr,Co,and Ni)were distributed in the coastal intertidal zone and estuary and remained unchanged or decreased after the typhoon.The heavy metal assessment showed that heavy metal pollution in Quanzhou Bay was serious and tended to increase after the typhoon.The increased metal supply and enhanced riverine and tidal hydrodynamics after the typhoon may be the main factors influencing the variations in heavy metal content and distribution.This study provided a basis for the accurate evaluation and scientific management of heavy metal pollution caused by typhoon processes in Quanzhou Bay.
文摘The western Bay of Bengal is particularly susceptible to the harmful impacts of increasing coastal pollution,as coastal population and urban development are occurring at unprecedented rates.The rapid urbanization and industrialization along the east coast of India coupled with the transfer of contaminants into the Bay of Bengal through riverine systems,causing a direct impact on marine ecosystems.In the present study,an attempt has been made to understand the heavy metal distribution on shelf sediments in the western part of the Bay of Bengal to infer their source,processes,and historical changes in marine pollution.Three short sediment core samples were collected and analysed for sediment texture,organic matter,and heavy metals.Cores 1 and 2 contain a high amount of sand content,representing shallow marine with moderate to high-energy conditions,and were deposited at a recent time.Core 3 was dominated by muddy sand to sandy mud,which denotes calm sedimentation without any turbulence,and these sediments were deposited under relatively low-energy conditions.The higher concentration of organic matter in the top layers of the core indicates both marine and terrestrial input.The heavy metal contents show quite heterogeneous and variable distributions from one element to another and from one core to another.The calculated pollution indices such as Contamination Factor(CF),and Geoaccumulation Index(Igeo)and Pollution Load Index(PLI)values indicate that all the core sub-samples are severely enriched and highly polluted by Cd and moderately polluted by Pb.The increased heavy metal concentration in the upper portion of the sediment cores and moderate to considerable ecological risks indicate that these metals have been deposited in the study area for the past few decades.
