Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are import...Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are important 'refueling' point along the East Asian/Australian flyway of migratory birds. The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid economic developments in Hong Kong and Shenzhen in recent decades. Macroinfauna of Mai Po and Futian mudflats was investigated in December 2000 and the faunal data were used to assess their environmental quality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Keng intertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfauna and used as reference mudflats. Shannon - Weaver species diversity index (Isd), biotic coefficient (Cb) and macrofaunal pollution index (Imp) of the macrofauna community on four intertidal mudflats were used to determine their environmental quality. The results showed that Luk Keng intertidal mudflat was unpolluted, Mai Po and Futian mudflats were slightly polluted, and Ma Wan was moderately polluted. The pollution in Ma Wan Typhoon Shelter mainly came from various types of rubbish and fishing boats that disturbed the sediment, while pollution sources in Mai Po and Futian mudflats were discharges of industrial water, municipal sewage and from nearby rivers.展开更多
Sewage sludge amendment （SSA） is an alternative waste disposal technique and a potential way to increase fertility of mudflats for crop growth. The present study aimed to assess the suitability of SSA by assessing t...Sewage sludge amendment （SSA） is an alternative waste disposal technique and a potential way to increase fertility of mudflats for crop growth. The present study aimed to assess the suitability of SSA by assessing the nitrogen （N） and phosphorous （P） uptakes, heavy metal accumulation, growth, biomass, and yield response of ryegrass （Lolium perenne L.） at 0, 30, 75, 150, and 300 t ha-1 SSA rates at various growth stages. The results showed that the highest biomass ofryegrass at seedling and vegetative stages were at 300 and 150 t ha-1 SSA rate, respectively. The increments of ryegrass yield at reproductive stage at 30, 75, 150, and 300 t ha1 SSA rates were 98.0, 122.6, 88.1, and 61.2%, compared to unamended soil. N and P concentrations in ryegrass increased with increasing SSA rates at all stages except N and P in roots dropped significantly at 300 t ha-1 rate at vegetative stage. The metal concentration for Mn, Cu, Zn, Ni, Cd, Cr, and Pb in shoot of ryegrass at 300 t ha-1 S SA rate increased by 0.63-, 2.34-, 15.02-, 0.97-, 10.00-, 0.01- and 1.13-fold, respectively, compared to unamended soil. However, heavy metal concentrations in shoot of ryegrass were lower than the standard for forage products in China. The study suggested that sewage sludge amendment in mudflat soils might be feasible. However, the impacts of sludge application on edible crop plants and soil environment need further investigations.展开更多
In order to examine the seasonal and spatial distributions of benthic animals in the intertidal mudflat of the southern Yellow River Delta,field investigations were carried out in 2007 and 2008 and multiple methods we...In order to examine the seasonal and spatial distributions of benthic animals in the intertidal mudflat of the southern Yellow River Delta,field investigations were carried out in 2007 and 2008 and multiple methods were applied.Results showed that,the biomass of macro benthos ranged at 0.75-1151.00 g wet m^(-2) and averaged at 156.31 g wet m^(-2),in which Mactra veneriformis accounted for 75.6%-93.4% of the total macro benthic biomass.More than 90% of macro benthos inhabited in the middle and low tide lines,and higher biomass occurred in early summer and lower in winter.Statistical analysis showed that:1)M.veneriformis growth was primarily favored at higher temperature and lower salinity;2)after long time interaction,benthic bivalve grazers led to patching distributions of Chlorophyll a(Chl a);3)macro benthic biomass positively related with Chl a when the concentration of Chl a was low,but they were negatively related when Chl a concentration was high;and 4)furthermore,the biomass of benthic bivalves peaked in the sediment with median grain size about 0.55 mm,but decreased gradually in coarse or fine sediments.The secondary productivity ranged at 0.37-283.68 g m^(-2)yr^(-1) and averaged at 47.88 g m^(-2) yr^(-1),in which 69.7% was contributed by M.veneriformis It was estimated that primary production was transformed to secondary production at a rate of 6.87%approximately,which implies that there is a local sustainability of high bivalve production.展开更多
Mudflats play a vital role in maintaining the dynamic balance between sea and land.To understand the characteristics,sources,and pollution risks of six heavy metals(As,Cd,Cr,Cu,Hg,and Pb)in the coastal mudflats on the...Mudflats play a vital role in maintaining the dynamic balance between sea and land.To understand the characteristics,sources,and pollution risks of six heavy metals(As,Cd,Cr,Cu,Hg,and Pb)in the coastal mudflats on the Leizhou Peninsula,257 surface sediment samples were studied using mathematical statistics,correlation analysis,and factor analysis.The results show that the overall concentrations of these heavy metals are low although there are several high abnormal points in the local areas.The strong correlation between these heavy metals indicates that the sources of some of the metals are similar,yet their elemental combinations in different cities(counties)varied.According to the calculated enrichment factor(EF),anthropogenic activity-induced heavy metals were determined in order of decreasing influence:As,Cd,Pb,Cr,Cu,and Hg.The low EF values of Hg indicate that it does not present as a contaminant in the study area,while low values of Cr and Cu from the Lianjiang City suggest that these two metals were also attributed to natural sources.The presence of As,Cd,Cr,Cu,and Pb from the remaining cities(counties)should be influenced by anthropogenic activities.The overall potential ecological risk index indicates that the ecological risks posed by the six analyzed heavy metals to the Leizhou Peninsula mudflats,in order of decreasing risk,are Cd,As,Hg,Pb,Cu,and Cr.It is noteworthy that only Cd in Lianjiang City demonstrated substantial ecological risk.Other examined heavy metals in other cities of the study area showed slight ecological risk.展开更多
Despite coastal mudflats serving as essential ecological zones interconnecting terrestrial/freshwater and marine systems,little is known about the profiles of antibiotic resistance genes(ARGs)in this area.In this stud...Despite coastal mudflats serving as essential ecological zones interconnecting terrestrial/freshwater and marine systems,little is known about the profiles of antibiotic resistance genes(ARGs)in this area.In this study,characteristics of typical ARGs,involving both intracellular(iARGs)and extracellular ARGs(eARGs)at different physical states,were explored in over 1000 km of coastal mudflats in Eastern China.Results indicated the presence of iARGs and eARGs at states of both freely present or attached by particles.The abundance of eARGs was significantly higher than that of iARGs(87.3%vs 12.7%),and their dominance was more significant than those in other habitats(52.7%-76.3%).ARG abundance,especially for eARGs,showed an increasing trend(p<0.05)from southern(Nantong)to northern(Lianyungang)coastalmudflats.Higher salinity facilitated the transformation from iARGs to eARGs,and smaller soil particle size was conducive to the persistence of eARGs in northern coastal mudflats.This study addresses the neglected function of coastal mudflats as eARGs reservoirs.展开更多
Directing at the characteristics of coastal mudfiat saline and alkaline land, the yield of salt-tolerant Spartina and rice could reach 5 925-8 280 kg/hm^2 by the techniques of land and water resource utilization, farm...Directing at the characteristics of coastal mudfiat saline and alkaline land, the yield of salt-tolerant Spartina and rice could reach 5 925-8 280 kg/hm^2 by the techniques of land and water resource utilization, farming improvement, construction of matched water system, seed selection and treatment, water direct seeding, seedling raising on seedbed, field transplanting, weeding, nutrient and water management, and disease and pest control, providing a scientific basis for the cultivation of Spartina and Rice in coast mudflat.展开更多
Non-barrier mudflats in the Changjiang Estuary is examined to obtain preservation potentials and deposition rates over different time scales. The preservation potential of couplet is ca. 46.6% within daily scale and d...Non-barrier mudflats in the Changjiang Estuary is examined to obtain preservation potentials and deposition rates over different time scales. The preservation potential of couplet is ca. 46.6% within daily scale and decreases as the time-interval extending, with 9.2% on a semi-lunar scale and 3.7% on a seasonal scale. In the long term, only 1.6% of daily deposition can potentially be preserved in the tidal flat sequence and other 98.4% have been eroded and leave sedimentary discordances, discernable or un-discernable, in the mudflat deposits. A negative log-linear relationship is examined between sedimentation rates and the time spans. The length of sedimentary hiatuses on the mudflat deposition were estimated with considerable uncertainty, but it can provide from an actualistic base some further insights into the nature and origin of ancient mudflat deposits with emphasis on the sedimentary discordances.展开更多
Understanding of erosion and accretion patterns over intertidal mudflats during storm periods is vital for the management and sustainable development of coastal areas.This study aimed to investigate the effect of the ...Understanding of erosion and accretion patterns over intertidal mudflats during storm periods is vital for the management and sustainable development of coastal areas.This study aimed to investigate the effect of the 2014 storm Fung-wong on the erosion and accretion patterns of the Nanhui intertidal mudflats in the Yangtze estuary,China,based on field measurements and Delft3D numerical modeling.Results show that prolonged easterly winds during the storm enhance the flood velocity,weaken the ebb velocity,and even change the current direction.The current velocity,wave heights,and bed-level changes increased by 1-1.43 times,2.40-3.88 times,and 2.28-2.70 times than those of normal weather,respectively.The mudflats show a spatial pattern of overall erosion but increasing erosion magnitude from the high(landward)mudflat to the low(seaward)mudflat during the storm.The magnitude of bed-level change increases with increasing wind speed,but the spatial pattern of erosion and accretion remains the same.The main reason for this pattern is the longer submersion duration of the low mudflat compared with the high mudflat,so the hydrodynamic process is longer and stronger,leading to an enhancement in bed shear stress and sediment transport rate.Wind speed increases the hydrodynamic intensity but does not affect on the submersion duration over each part of the intertidal mudflat.This study is helpful to improve the understanding of physical processes during storms on intertidal mudflats and provides a reference for their protection,utilization,and management,as well as for research in related disciplines.展开更多
The diffusion boundary layer (DBL) significantly limits the exchange between sediment and overlying water and therefore becomes a bottleneck of diffusive vertical flux at the sediment-water interface (SWI). Variable D...The diffusion boundary layer (DBL) significantly limits the exchange between sediment and overlying water and therefore becomes a bottleneck of diffusive vertical flux at the sediment-water interface (SWI). Variable DBL thickness and diffusion flux in response to dynamic forcing may influence replenishment of nutrients and secondary pollution in coastal waters. In situ measurements of velocity in the bottom boundary layer (BBL) and oxygen concentration in the DBL were made over an intertidal mudflat, using an acoustic Doppler current and mini profiler. A linear distributed zone in the oxygen profile, the profile slope discontinuity and variance of concentration can be used to derive accurate DBL thickness. Diffusion fluxes calculated from the water column and sediment are identical, and their bias is less than 6%. A numerical model PROFILE is used to simulate the in situ dissolved oxygen profile, and layered dissolved oxygen consumption rates in the sediment are calculated. The DBL thickness (0.10-0.35 mm) and diffusion flux (15.4-53.6 mmol m 2 d 1) vary with a factor of 3.5 during a tidal period. Over an intertidal mudflat, DBL thickness is controlled by flow speed U in the BBL, according to δDBL=1686.1DU 1+0.1 (D is the molecular diffusion coefficient). That is, the DBL thickness δDBL increases with decreasing flow speed U. Changes of diffusion flux at the SWI are caused by variations in the water above the sediment and the turbulent mixing intensity. The diffusion flux is positively related to the turbulent dissipation rate, friction velocity and turbulent energy. Under the influence of dynamics in the BBL, DBL thickness and flux vary significantly.展开更多
文摘Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are important 'refueling' point along the East Asian/Australian flyway of migratory birds. The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid economic developments in Hong Kong and Shenzhen in recent decades. Macroinfauna of Mai Po and Futian mudflats was investigated in December 2000 and the faunal data were used to assess their environmental quality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Keng intertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfauna and used as reference mudflats. Shannon - Weaver species diversity index (Isd), biotic coefficient (Cb) and macrofaunal pollution index (Imp) of the macrofauna community on four intertidal mudflats were used to determine their environmental quality. The results showed that Luk Keng intertidal mudflat was unpolluted, Mai Po and Futian mudflats were slightly polluted, and Ma Wan was moderately polluted. The pollution in Ma Wan Typhoon Shelter mainly came from various types of rubbish and fishing boats that disturbed the sediment, while pollution sources in Mai Po and Futian mudflats were discharges of industrial water, municipal sewage and from nearby rivers.
基金financially supported by the National Natural Science Foundation of China(31101604)the Public Foundation of Key Laboratory of Environmental Materials and Engineering of Jiangsu Province,China(JHCG201011)the Foundation of Jiangsu Educational Committee,China(12KJB210008)
文摘Sewage sludge amendment （SSA） is an alternative waste disposal technique and a potential way to increase fertility of mudflats for crop growth. The present study aimed to assess the suitability of SSA by assessing the nitrogen （N） and phosphorous （P） uptakes, heavy metal accumulation, growth, biomass, and yield response of ryegrass （Lolium perenne L.） at 0, 30, 75, 150, and 300 t ha-1 SSA rates at various growth stages. The results showed that the highest biomass ofryegrass at seedling and vegetative stages were at 300 and 150 t ha-1 SSA rate, respectively. The increments of ryegrass yield at reproductive stage at 30, 75, 150, and 300 t ha1 SSA rates were 98.0, 122.6, 88.1, and 61.2%, compared to unamended soil. N and P concentrations in ryegrass increased with increasing SSA rates at all stages except N and P in roots dropped significantly at 300 t ha-1 rate at vegetative stage. The metal concentration for Mn, Cu, Zn, Ni, Cd, Cr, and Pb in shoot of ryegrass at 300 t ha-1 S SA rate increased by 0.63-, 2.34-, 15.02-, 0.97-, 10.00-, 0.01- and 1.13-fold, respectively, compared to unamended soil. However, heavy metal concentrations in shoot of ryegrass were lower than the standard for forage products in China. The study suggested that sewage sludge amendment in mudflat soils might be feasible. However, the impacts of sludge application on edible crop plants and soil environment need further investigations.
基金supported by the National Natural Science Foundation of China(No.41176064)NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406403)
文摘In order to examine the seasonal and spatial distributions of benthic animals in the intertidal mudflat of the southern Yellow River Delta,field investigations were carried out in 2007 and 2008 and multiple methods were applied.Results showed that,the biomass of macro benthos ranged at 0.75-1151.00 g wet m^(-2) and averaged at 156.31 g wet m^(-2),in which Mactra veneriformis accounted for 75.6%-93.4% of the total macro benthic biomass.More than 90% of macro benthos inhabited in the middle and low tide lines,and higher biomass occurred in early summer and lower in winter.Statistical analysis showed that:1)M.veneriformis growth was primarily favored at higher temperature and lower salinity;2)after long time interaction,benthic bivalve grazers led to patching distributions of Chlorophyll a(Chl a);3)macro benthic biomass positively related with Chl a when the concentration of Chl a was low,but they were negatively related when Chl a concentration was high;and 4)furthermore,the biomass of benthic bivalves peaked in the sediment with median grain size about 0.55 mm,but decreased gradually in coarse or fine sediments.The secondary productivity ranged at 0.37-283.68 g m^(-2)yr^(-1) and averaged at 47.88 g m^(-2) yr^(-1),in which 69.7% was contributed by M.veneriformis It was estimated that primary production was transformed to secondary production at a rate of 6.87%approximately,which implies that there is a local sustainability of high bivalve production.
基金The Guangdong,Guizhou,Hunan and Jiangxi 1:250000 Land Quality Geochemical Survey under contract No.DD20160327-04the National Natural Science Foundation of China under contract No.U1911202+1 种基金the Guangdong Basic and Applied Basic Research Foundation under contract No.2021A1515011547the Guangzhou Basic and Applied Basic Research Foundation under contract No.202102020465.
文摘Mudflats play a vital role in maintaining the dynamic balance between sea and land.To understand the characteristics,sources,and pollution risks of six heavy metals(As,Cd,Cr,Cu,Hg,and Pb)in the coastal mudflats on the Leizhou Peninsula,257 surface sediment samples were studied using mathematical statistics,correlation analysis,and factor analysis.The results show that the overall concentrations of these heavy metals are low although there are several high abnormal points in the local areas.The strong correlation between these heavy metals indicates that the sources of some of the metals are similar,yet their elemental combinations in different cities(counties)varied.According to the calculated enrichment factor(EF),anthropogenic activity-induced heavy metals were determined in order of decreasing influence:As,Cd,Pb,Cr,Cu,and Hg.The low EF values of Hg indicate that it does not present as a contaminant in the study area,while low values of Cr and Cu from the Lianjiang City suggest that these two metals were also attributed to natural sources.The presence of As,Cd,Cr,Cu,and Pb from the remaining cities(counties)should be influenced by anthropogenic activities.The overall potential ecological risk index indicates that the ecological risks posed by the six analyzed heavy metals to the Leizhou Peninsula mudflats,in order of decreasing risk,are Cd,As,Hg,Pb,Cu,and Cr.It is noteworthy that only Cd in Lianjiang City demonstrated substantial ecological risk.Other examined heavy metals in other cities of the study area showed slight ecological risk.
基金This study was supported by the National Natural Science Foundation of China(No.42177348)the Natural Science Foundation of Jiangsu Province(No.BK20201367)China Postdoctoral Science Foundation(No.2021M701663).
文摘Despite coastal mudflats serving as essential ecological zones interconnecting terrestrial/freshwater and marine systems,little is known about the profiles of antibiotic resistance genes(ARGs)in this area.In this study,characteristics of typical ARGs,involving both intracellular(iARGs)and extracellular ARGs(eARGs)at different physical states,were explored in over 1000 km of coastal mudflats in Eastern China.Results indicated the presence of iARGs and eARGs at states of both freely present or attached by particles.The abundance of eARGs was significantly higher than that of iARGs(87.3%vs 12.7%),and their dominance was more significant than those in other habitats(52.7%-76.3%).ARG abundance,especially for eARGs,showed an increasing trend(p<0.05)from southern(Nantong)to northern(Lianyungang)coastalmudflats.Higher salinity facilitated the transformation from iARGs to eARGs,and smaller soil particle size was conducive to the persistence of eARGs in northern coastal mudflats.This study addresses the neglected function of coastal mudflats as eARGs reservoirs.
文摘Directing at the characteristics of coastal mudfiat saline and alkaline land, the yield of salt-tolerant Spartina and rice could reach 5 925-8 280 kg/hm^2 by the techniques of land and water resource utilization, farming improvement, construction of matched water system, seed selection and treatment, water direct seeding, seedling raising on seedbed, field transplanting, weeding, nutrient and water management, and disease and pest control, providing a scientific basis for the cultivation of Spartina and Rice in coast mudflat.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 49976016 and 40046019) also by the State Key Laboratory for Estuarine and Coastal Research.
文摘Non-barrier mudflats in the Changjiang Estuary is examined to obtain preservation potentials and deposition rates over different time scales. The preservation potential of couplet is ca. 46.6% within daily scale and decreases as the time-interval extending, with 9.2% on a semi-lunar scale and 3.7% on a seasonal scale. In the long term, only 1.6% of daily deposition can potentially be preserved in the tidal flat sequence and other 98.4% have been eroded and leave sedimentary discordances, discernable or un-discernable, in the mudflat deposits. A negative log-linear relationship is examined between sedimentation rates and the time spans. The length of sedimentary hiatuses on the mudflat deposition were estimated with considerable uncertainty, but it can provide from an actualistic base some further insights into the nature and origin of ancient mudflat deposits with emphasis on the sedimentary discordances.
基金provided by the Natural Science Foundation of China(Grant number:42076170,42176164)the Key Laboratory of Coastal Salt Marsh Ecosystems and Resources,Ministry of Natural Resources(Grant number:KLCSMERMNR2021108)Jiangsu Special Program for Science and Technology Innovation(Grant number:JSZRHYKJ202106).
文摘Understanding of erosion and accretion patterns over intertidal mudflats during storm periods is vital for the management and sustainable development of coastal areas.This study aimed to investigate the effect of the 2014 storm Fung-wong on the erosion and accretion patterns of the Nanhui intertidal mudflats in the Yangtze estuary,China,based on field measurements and Delft3D numerical modeling.Results show that prolonged easterly winds during the storm enhance the flood velocity,weaken the ebb velocity,and even change the current direction.The current velocity,wave heights,and bed-level changes increased by 1-1.43 times,2.40-3.88 times,and 2.28-2.70 times than those of normal weather,respectively.The mudflats show a spatial pattern of overall erosion but increasing erosion magnitude from the high(landward)mudflat to the low(seaward)mudflat during the storm.The magnitude of bed-level change increases with increasing wind speed,but the spatial pattern of erosion and accretion remains the same.The main reason for this pattern is the longer submersion duration of the low mudflat compared with the high mudflat,so the hydrodynamic process is longer and stronger,leading to an enhancement in bed shear stress and sediment transport rate.Wind speed increases the hydrodynamic intensity but does not affect on the submersion duration over each part of the intertidal mudflat.This study is helpful to improve the understanding of physical processes during storms on intertidal mudflats and provides a reference for their protection,utilization,and management,as well as for research in related disciplines.
基金supported by the National Basic Research Program of China (2011CB403606)the National Natural Science Foundation of China (40830854 and 40806001)
文摘The diffusion boundary layer (DBL) significantly limits the exchange between sediment and overlying water and therefore becomes a bottleneck of diffusive vertical flux at the sediment-water interface (SWI). Variable DBL thickness and diffusion flux in response to dynamic forcing may influence replenishment of nutrients and secondary pollution in coastal waters. In situ measurements of velocity in the bottom boundary layer (BBL) and oxygen concentration in the DBL were made over an intertidal mudflat, using an acoustic Doppler current and mini profiler. A linear distributed zone in the oxygen profile, the profile slope discontinuity and variance of concentration can be used to derive accurate DBL thickness. Diffusion fluxes calculated from the water column and sediment are identical, and their bias is less than 6%. A numerical model PROFILE is used to simulate the in situ dissolved oxygen profile, and layered dissolved oxygen consumption rates in the sediment are calculated. The DBL thickness (0.10-0.35 mm) and diffusion flux (15.4-53.6 mmol m 2 d 1) vary with a factor of 3.5 during a tidal period. Over an intertidal mudflat, DBL thickness is controlled by flow speed U in the BBL, according to δDBL=1686.1DU 1+0.1 (D is the molecular diffusion coefficient). That is, the DBL thickness δDBL increases with decreasing flow speed U. Changes of diffusion flux at the SWI are caused by variations in the water above the sediment and the turbulent mixing intensity. The diffusion flux is positively related to the turbulent dissipation rate, friction velocity and turbulent energy. Under the influence of dynamics in the BBL, DBL thickness and flux vary significantly.
