Salt marshes are among the most important coastal wetlands and provide critical ecological services,including climate regulation,biodiversity maintenance,and blue carbon sequestration.However,most salt marshes worldwi...Salt marshes are among the most important coastal wetlands and provide critical ecological services,including climate regulation,biodiversity maintenance,and blue carbon sequestration.However,most salt marshes worldwide are shrinking,owing to the effects of natural and human factors,such as climate change and artificial reclamation.Therefore,it is essential to understand the decline in the morphological processes of salt marshes,and accordingly,the likely evolution of these marshes,in order to enable measures to be taken to mitigate this decline.To this end,this study presented an extensive systematic review of the current state of morphological models and their application to salt marshes.The emergence of process-based(PB)and data-driven(DD)models has contributed to the development of morphological models.In morphodynamic simulations in PB models,multiple physical and biological factors(e.g.,the hydrodynamics of water bodies,sediment erosion,sediment deposition,and vegetation type)have been considered.The systematic review revealed that PB models have been extended to a broader interdisciplinary field.Further,most DD models are based on remote sensing database for the prediction of morphological characteristics with latent uncertainty.Compared to DD models,PB models are more transparent but can be complex and require a lot of computational power.Therefore,to make up for the shortcomings of each model,future studies could couple PB with DD models that consider vegetation,microorganisms,and benthic animals together to simulate or predict the biogeomorphology of salt marsh systems.Nevertheless,this review found that there is a lack of unified metrics to evaluate model performance,so it is important to define clear objectives,use multiple metrics,compare multiple models,incorporate uncertainty,and involve experts in the field to provide guidance in the further study.展开更多
Based on plant specimen data,sediment samples,photos,and sketches from 45 coastal cross-sections,and materials from two recent countrywide comprehensive investigations on Chinese coasts and is-lands,this paper deals w...Based on plant specimen data,sediment samples,photos,and sketches from 45 coastal cross-sections,and materials from two recent countrywide comprehensive investigations on Chinese coasts and is-lands,this paper deals with China’s vegetative tidal-flats:salt marshes and mangrove swamps.Thereare now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about30% of the mud-coast area of the country and distribute between 18°N(Southem Hainan Island)and41°N(Liaodong Bay).Over the past 45 years.about 1750000 acres of salt marshes and 49400 acres ofmangrove swamps have been reclaimed.The2.0×10~9 tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats,the soil basis of coastal helophytes.Different climates result inthe diversity of vegetation.The 3~8m tidal range favors intertidal zone development.Of over 20plant species in the salt marshes,native Suaeda salsa,Phragmites australis,Aeluropus littoralis,Zoysiamaerostachys,Imperata cylindrica and展开更多
Characteristics and tidal flat trends of soil organic matter (SOM) turnover were studied for the Chongmingdongtan Salt Marsh in the Yangtze River estuary, based on analyses of stable carbon isotope composition (δ^...Characteristics and tidal flat trends of soil organic matter (SOM) turnover were studied for the Chongmingdongtan Salt Marsh in the Yangtze River estuary, based on analyses of stable carbon isotope composition (δ^13C), grain sizes and contents of particulate organic carbon (POC), total nitrogen (TN) and inorganic carbon (TIC) for three cores excavated from high tidal flat, middle tidal flat and bare flat. Results demonstrate that correlations between soil POC contents and δ^13C values of the salt marsh cores were similar to those between soil organic carbon (SOC) contents and δ^13C values of the upper soil layers of mountainous soil profiles with different altitudes. SOM of salt marsh was generally younger than 100 years, and originated mainly from topsoil erosions in catchments of the Yangtze River. Correlations of TN content with C/N ratio, POC content with TIC content and POC content with δ^13C values for the cores suggest that turnover degrees of SOM from the salt marsh are overall low, and trends of SOM turnover are clear from the bare flat to the high tidal flat. Bare flat samples show characteristics of original sediments, with minor SOM turnover. Turnover processes of SOM have occurred and are discernable in the high and middle tidal flats, and the mixing degrees of SOM compartments with different turnover rates increase with evolution of the muddy tidal flat. The exclusive strata structure of alternate muddy laminae and silty laminae originated from dynamic depositional processes on muddy tidal flat was a great obstacle to vertical migration of dissolved materials, and SOM turnover was then constrained. The muddy tidal flat processes exerted direct influences on sequestration and turnover of SOM in the salt marsh, and had great constraints on the spatial and temporal characteristics of SOM turnover of the Chongmingdongtan Salt Marsh in the Yangtze River estuary.展开更多
The effects of nitrogen (N) addition on microbial biomass, bacterial abundance, and community composition in sediment colonized by Suaeda heteroptera were examined by chloroform fumigation extraction method, real-ti...The effects of nitrogen (N) addition on microbial biomass, bacterial abundance, and community composition in sediment colonized by Suaeda heteroptera were examined by chloroform fumigation extraction method, real-time quantitative polymerase chain reaction, and denaturing gradient gel electrophoresis (DGGE) in a salt marsh located in Shuangtai Estuary, China. The sediment samples were collected from plots treated with different amounts of a single N fertilizer (urea supplied at 0.1, 0.2, 0.4 and 0.8 g/kg (nitrogen content in sediment) and different forms of N fertilizers (urea, (NH4)2SO4, and NH4NO3, each supplied at 0.2 g/kg (calculated by nitrogen). The fertilizers were applied 1-4 times during the plant-growing season in May, luly, August, and September of 2013. Untreated plots were included as a control. The results showed that both the amount and form of N positively influenced microbial biomass carbon, microbial biomass nitrogen, and bacterial abundance. The DGGE profiles revealed that the bacterial community composition was also affected by the amount and form of N. Thus, our findings indicate that short-term N amendment increases microbial biomass and bacterial abundance, and alters the structure of bacterial community.展开更多
To obtain information on food web structure in salt marshes of the Changjiang (Yangtze) River Estuary, the ( δ3C and δ15N values of primary producers and consumers were determined. The mean δ13C values of 31 d...To obtain information on food web structure in salt marshes of the Changjiang (Yangtze) River Estuary, the ( δ3C and δ15N values of primary producers and consumers were determined. The mean δ13C values of 31 dominant consumers ranged from -23.13‰ to -14.37‰. Except for several species ( Eriocheir sinensis, Sinonovacula constricta and Potamocorbula ustulata), consumers had interme- diate δ13C values between those of benthic microalgae and Spartina alterniflora. The mean δ15N values of 31 dominant consumers varied between 6.87‰ and 13.33‰, which indicate three trophic levels in salt marshes of the Changjiang River Estuary. A total of 18 macroinvertebrates species and four fish species represented primary consumers with trophic levels ranging from 2.0 to 2.7. Secondary consumers included two maeroinvertebrates and seven fishes with trophic levels varying between 3.0 and 3.9. The consumers were divided into three trophic guilds, i.e., detritivorous/algae feeders, omnivores and carnivores. The detrital food chain was the main energy flow pathway in the salt marsh food web of the Changjiang River Estuary, and the marsh vascular plants were at least as equally important as microphytobenthos for secondary production. The important trophic function of the salt marsh habitats in the estuary is revealed.展开更多
In western Songnen Plain of China, the saline-alkaline degree of water bodies is high in salt marsh wetlands. Generally, pH is above 8.0, and the hydrochemical types belong to HCO3 2?-Na+. Through analysis on the basi...In western Songnen Plain of China, the saline-alkaline degree of water bodies is high in salt marsh wetlands. Generally, pH is above 8.0, and the hydrochemical types belong to HCO3 2?-Na+. Through analysis on the basic saline variables such as CO3 2?, HCO3 2?, Cl?, Ca2+, Mg2+, SO4 2?, Na+, and the derivative variables such as SAR, SDR, RSC, SSP, the relationships between different variables are found, and the discriminant equations are established to identify different saline-alkaline water bodies by using principal component analysis.展开更多
The analysis of vegetation-environment relationships has always been a study hotspot in ecology. A number of biotic, hydrologic and edaphic factors have great influence on the distribution of macrophytes within salt m...The analysis of vegetation-environment relationships has always been a study hotspot in ecology. A number of biotic, hydrologic and edaphic factors have great influence on the distribution of macrophytes within salt marsh.Since the exotic species Spartina alterniflora(S. alterniflora) was introduced in 1995, a rapid expansion has occurred at Chongming Dongtan Nature Reserve(CDNR) in the Changjiang(Yangtze) River Estuary, China.Several important vegetation-environment factors including soil elevation, tidal channels density(TCD),vegetation classification and fractional vegetation cover(FVC) were extracted by remote sensing method combined with field measurement. To ignore the details in interaction between biological and physical process,the relationship between them was discussed at a large scale of the whole saltmarsh. The results showed that Scirpus mariqueter(S. mariqueter) can endure the greatest elevation variance with 0.33 m throughout the marsh in CDNR. But it is dominant in the area less than 2.5 m with the occurrence frequency reaching 98%. S. alterniflora has usually been found on the most elevated soils higher than 3.5 m but has a narrow spatial distribution. The rapid decrease of S. mariqueter can be explained by stronger competitive capacity of S. alterniflora on the high tidal flat. FVC increases with elevation which shows significant correlation with elevation(r=0.30, p〈0.001). But the frequency distribution of FVC indicates that vegetation is not well developed on both elevated banks near tidal channels from the whole scale mainly due to tidal channel lateral swing and human activities. The significant negative correlation(r=–0.20, p〈0.001) was found between FVC and TCD, which shows vegetation is restricted to grow in higher TCD area corresponding to lower elevation mainly occupied by S. mariqueter communities. The maximum occurrence frequency of this species reaches to 97% at the salt marsh with TCD more than 8 m/m2.展开更多
Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nit...Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P < 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P > 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.展开更多
Salt marshes are among the most common morphological features found in tidal landscapes and provide ecosystem services of primary ecological and economic importance.However,the continued rise in relative sea level and...Salt marshes are among the most common morphological features found in tidal landscapes and provide ecosystem services of primary ecological and economic importance.However,the continued rise in relative sea level and increasing anthropogenic pressures threaten the sustainability of these environments.The alarmingly high rates of salt marsh loss observed worldwide,mainly dictated by the lateral erosion of their margins,call for new insights into the mutual feedbacks among physical,biological,and morphological processes that take place at the critical interface between salt marshes and the adjoining tidal flats.We combined field measurements,remote sensing data,and numerical modeling to investigate the interplays between wind waves and the morphology,ecology,and planform evolution of salt marsh margins in the Venice Lagoon of Italy.Our results confirm the existence of a positive linear relationship between incoming wave power density and rates of salt marsh lateral retreat.In addition,we show that lateral erosion significantly decreases when halophytic vegetation colonizes the marsh margins,and that different erosion rates in vegetated margins are associated with different halophytes.High marsh cliffs and smooth shorelines are expected along rapidly eroding margins,whereas erosion rates are reduced in gently sloped,irregular edges facing shallow tidal flats that are typically exposed to low wind-energy conditions.By highlighting the relationships between the dynamics and functional forms of salt marsh margins,our results represent a critical step to address issues related to conservation and restoration of salt marsh ecosystems,especially in the face of changing environmental forcings.展开更多
In this study, we examined the influence of changes in the degree and frequency of disturbance in estuarine tidal flats on the annual salt marsh plant communities (Suaeda maritima, Artemisia fukudo) in Mie Prefecture,...In this study, we examined the influence of changes in the degree and frequency of disturbance in estuarine tidal flats on the annual salt marsh plant communities (Suaeda maritima, Artemisia fukudo) in Mie Prefecture, Japan. Suaeda maritima and Artemisia fukudo communities occur in the branch river of the Kushida River. Although the areas occupied by these communities were very small in 2006, the Suaeda maritima community expanded significantly to 3609 m2 in 2008, and the Artemisia fukudo community expanded significantly to 2726 m2 in 2008 and 10,396 m2 in 2010. Before the onset of the investigation period in 2006, the overflow warning water level (3.5 m) and the flood fighting corps standby water level (3.0 m) each occurred on one day in August 2004 and October 2004, respectively;at those times, the water volume exceeded 1000 m3·s-1 and 1500 m3·s-1, respectively. We suggest that because much of the estuarine tidal flat erodes when the water volume exceeds 1000 m3·sǃ, the establishment of the Suaeda maritima and Artemisia fukudo communities is delayed until sufficient substrate is formed by the deposition of new sediment. In contrast, a water level of 2 - 3 m was observed on one day each in 2005, 2007 and 2009, with average water volumes of 488.5, 566.4 and 690.1 m3·s-1, respectively. We suggest that following the repeated disturbances caused by water levels of 1 - 3 m and flow volumes of 500 - 700 m3·s-1 over the bare ground exposed after flooding and erosion, Suaeda maritima is a pioneer species that colonizes on bare ground deposited by sediment transported from upstream and the sea during high tides, and following the same level of disturbance, Artemisia fukudo is secondary colonizer that has germinated and grown on the sediment deposited on the Suaeda maritima community.展开更多
During the past century,natural and human modifications of environmental systems have greatly accelerated coastal salt marsh deterioration and shoreline retreat in many regions worldwide. Field investigation,profile a...During the past century,natural and human modifications of environmental systems have greatly accelerated coastal salt marsh deterioration and shoreline retreat in many regions worldwide. Field investigation,profile analysis,geographical information analysis,and remote sensing were employed in combination to study the effect of sediment on Spartina alterniflora salt marshes of the coast in Jiangsu Province,East China. The results indicated that the propagation of Spartina alterniflora salt marshes was closely related to regional sediment conditions,especially the supply of fine-grained materials. Additionally,because of the dense and high grass in Spartina alterniflora salt marshes,wave energy and tidal currents were baffled and weaker than those of the adjacent,unvegetated mud flats. Fine sediment was hardly resuspended under the low energy conditions in the Spartina alterniflora salt marshes.展开更多
Coastal wetlands are the most productive ecosystems worldwide and can provide important ecosystem services,yet the characteristics of microbial community within these systems remain poorly understood.Microbial communi...Coastal wetlands are the most productive ecosystems worldwide and can provide important ecosystem services,yet the characteristics of microbial community within these systems remain poorly understood.Microbial community of salt marsh vegetation and the associated soil physio-chemical properties were investigated in this study.Three typical Suaeda australis,Phragmites australis,Spartina alterniflora wetlands,and non-vegetated bare mudflats in the Zhoushan Islands were studied to advance the understanding of the characteristics of soil bacterial communities in coastal wetlands.Results showed that the bare mudflats exhibited high pH value and soil moisture content compared with the vegetated samples.In different vegetation types,the organic matter content,total nitrogen,and total potassium content decreased in the order:S.alterniflora wetland>P.australis wetland>S.australis wetland,and there was no obvious difference in total phosphorous content.The halophytes could decrease soil salinity compared with bare mudflats.Proteobacteria,Nitrospinae,Bacteroidetes,Acidobacteria,and Nitrospirae were the predominant level across all samples.Functional prediction showed that SPA-covered soil might play vital roles in sulphur cycling,while SUA and PHR covered soils were involved in nitrogen cycling.This study could provide the first insight into the microbial community of this study area and contribute to a better understanding of vegetation microbiota and bioremediation in coastal wetland ecosystem.展开更多
Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic car...Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.展开更多
Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this s...Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this study,we explored the changes of tidal flat and salt marsh coverage in a small-scale tidal flat with an area of ~160 000 m^2 in the plain coast of Jiangsu Province,China.Human activities(e.g.,the construction of dikes) are a crucial contributor that benefits for the tidal flat accretions and the following changes of salt marsh coverage.Located in the front of the man-made "concave coastline",the study area is suitable for sediment accretion after the dike construction in the end of 2006.On the basis of the annual tidal surface elevation survey from 2007 to 2012,the sedimentation rates in the human influenced tidal flat varied from a few centimeters per year to 23 cm/a.The study area experienced a rapid accretion in the tidal flat and the expansion of the salt marsh,with the formation of a longshore bar,and a subsequent decline of the salt marsh.Breaking waves during the flooding tide brought much sediment from the adjacent tidal flat to the study area,which caused burial and degeneration of the salt marsh.The vertical grain size changes within a 66 cm long core in the study area also demonstrated the above changes in the tidal environment.This study indicates that the responses of small-scale tidal flat changes to reclamation are significant,and the rational reclamation would benefit for the new salt marsh formation in front of the dikes.Further research about the evolution of small scale tidal flat as well as the spatial planning of the polder dike should be strengthened for the purpose to maintain a healthier coastal environment.展开更多
Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt...Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.展开更多
Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year.A total of 1 996 fish specimens (10 967.8 g) comprising 26 spec...Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year.A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected.Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%),Collichthys lucidus (18.6%),Periophthalmus magnuspinnatus (18.2%),Liza haematocheilus (17.9%),and secondarily by Mugilogobius abei (8.5%),L.carinatus (7.2%),Odontamblyopus lacepedii (4.3%),and Acanthogobius ommaturus (3.9%);another 18 species were present only occasionally.Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek.In spring,the communities were dominated by B.pectinirostris,P.magnuspinnatus,C.lucidus and M.abei;in summer,autumn,and winter by L.haematocheilus,L.carinatus,A.ommaturus and O.lacepedii.Some species showed strong habitat selection;L.carinatus and P.magnuspinnatus were distributed mainly in the upper and middle creek,while B.pectinirostris,M.abei and O.lacepedii inhabited the middle and lower creek.The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.展开更多
Between April 2002 and April 2003,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Chang...Between April 2002 and April 2003,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Changjiang (Yangtze) Estuary under different weather conditions.Cross-shore suspended sediment flux was calculated and analyzed.The results show that under calm weather conditions,the current velocity process in bald field and salt marsh area varied differently during semidiurnal tidal cycles.Owing to current velocity asymmetry,mean SSC during flood tide phase was 1.8 times higher than that of ebb tide phase.As a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally accreting.There was significant positive correlation between total sediment flux and quartic power of maximum water depth.It indicates that tidal ranges dominate suspended sediment transport and sedimentation process in the salt marsh pioneer zone under the calm weather condition.The sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stable accreting of salt marsh towards the sea.The wind events enhanced SSC and current velocity during the semidiurnal tides.And the remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.展开更多
The Tuckerton Peninsula, a large expanse (~2000 ha) of highly inundated Spartina alterniflora salt marsh habitat, forms one of the most extensive coastal wetland systems in New Jersey (USA). It is projected to be amon...The Tuckerton Peninsula, a large expanse (~2000 ha) of highly inundated Spartina alterniflora salt marsh habitat, forms one of the most extensive coastal wetland systems in New Jersey (USA). It is projected to be among the first salt marsh systems in New Jersey to be lost by rising sea level driven by climate change. The changes that occur in the demographic, ecologic, and ecogeomorphic characteristics of the salt marsh habitat at this location will be vital to understanding future habitat change in coastal wetlands in the Mid-Atlantic region. As a consequence, the Tuckerton Peninsula salt marsh system is designated as a sentinel site of the Jacques Cousteau National Estuarine Research Reserve (JCNERR) for the detection, monitoring, and assessment of climate change effects, most notably sea-level rise and inundation. Development of the Tuckerton Peninsula as a sentinel site requires a high accuracy local geodetic control network to connect existing water quality monitoring stations, vegetation transects and monitoring surface elevation tables, ground water wells, and digital elevation models on the same vertical datum. The integration of these monitoring infrastructure components is crucial to effective operation of the sentinel site. It will enable the collection of essential data to assess rates of marsh migration and upland transgression, as well as delineate key natural and anthropogenic drivers influencing habitat condition and change. The JCNERR sentinel site designation supports the National Oceanic and Atmospheric Administration’s long-term goal of assessing coastal vulnerability in the USA to climate change and generating data useful for forging climate adaptation and mitigation initiatives for coastal communities. Habitat and vertical control data collected at this sentinel site will be made available to decision makers across the nation and will enable them to determine how the loss of critical salt marsh habitat will affect coastal communities, their adaptation to future habitat loss, and their development of mitigation plans to address impacts and enhance resiliency.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2040204)the Jiangsu Provincial Natural Science Foundation of China(Grants No.BK2020020,BK20220979,and BK20220993)the Fundamental Research Funds for the Central University(Grant No.B220202057).
文摘Salt marshes are among the most important coastal wetlands and provide critical ecological services,including climate regulation,biodiversity maintenance,and blue carbon sequestration.However,most salt marshes worldwide are shrinking,owing to the effects of natural and human factors,such as climate change and artificial reclamation.Therefore,it is essential to understand the decline in the morphological processes of salt marshes,and accordingly,the likely evolution of these marshes,in order to enable measures to be taken to mitigate this decline.To this end,this study presented an extensive systematic review of the current state of morphological models and their application to salt marshes.The emergence of process-based(PB)and data-driven(DD)models has contributed to the development of morphological models.In morphodynamic simulations in PB models,multiple physical and biological factors(e.g.,the hydrodynamics of water bodies,sediment erosion,sediment deposition,and vegetation type)have been considered.The systematic review revealed that PB models have been extended to a broader interdisciplinary field.Further,most DD models are based on remote sensing database for the prediction of morphological characteristics with latent uncertainty.Compared to DD models,PB models are more transparent but can be complex and require a lot of computational power.Therefore,to make up for the shortcomings of each model,future studies could couple PB with DD models that consider vegetation,microorganisms,and benthic animals together to simulate or predict the biogeomorphology of salt marsh systems.Nevertheless,this review found that there is a lack of unified metrics to evaluate model performance,so it is important to define clear objectives,use multiple metrics,compare multiple models,incorporate uncertainty,and involve experts in the field to provide guidance in the further study.
基金The project was supported by the NSFC(No.49476281)
文摘Based on plant specimen data,sediment samples,photos,and sketches from 45 coastal cross-sections,and materials from two recent countrywide comprehensive investigations on Chinese coasts and is-lands,this paper deals with China’s vegetative tidal-flats:salt marshes and mangrove swamps.Thereare now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about30% of the mud-coast area of the country and distribute between 18°N(Southem Hainan Island)and41°N(Liaodong Bay).Over the past 45 years.about 1750000 acres of salt marshes and 49400 acres ofmangrove swamps have been reclaimed.The2.0×10~9 tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats,the soil basis of coastal helophytes.Different climates result inthe diversity of vegetation.The 3~8m tidal range favors intertidal zone development.Of over 20plant species in the salt marshes,native Suaeda salsa,Phragmites australis,Aeluropus littoralis,Zoysiamaerostachys,Imperata cylindrica and
基金Foundation: National Natural Science foundation of China, No.40202032 National 973 Project, No.2002CB412403 Program for Young Teachers in Universities in Shanghai, No.2000QN 14 Acknowledgments: We are grateful to the members taking part in a field survey supervised by Professor Zhang Jing for their kind helps in sampling the studied cores in this paper. Thanks are also extended to Mr. Wu Runming and Mr. Zhang Guosen for their instructions and helps in laboratory analyses.
文摘Characteristics and tidal flat trends of soil organic matter (SOM) turnover were studied for the Chongmingdongtan Salt Marsh in the Yangtze River estuary, based on analyses of stable carbon isotope composition (δ^13C), grain sizes and contents of particulate organic carbon (POC), total nitrogen (TN) and inorganic carbon (TIC) for three cores excavated from high tidal flat, middle tidal flat and bare flat. Results demonstrate that correlations between soil POC contents and δ^13C values of the salt marsh cores were similar to those between soil organic carbon (SOC) contents and δ^13C values of the upper soil layers of mountainous soil profiles with different altitudes. SOM of salt marsh was generally younger than 100 years, and originated mainly from topsoil erosions in catchments of the Yangtze River. Correlations of TN content with C/N ratio, POC content with TIC content and POC content with δ^13C values for the cores suggest that turnover degrees of SOM from the salt marsh are overall low, and trends of SOM turnover are clear from the bare flat to the high tidal flat. Bare flat samples show characteristics of original sediments, with minor SOM turnover. Turnover processes of SOM have occurred and are discernable in the high and middle tidal flats, and the mixing degrees of SOM compartments with different turnover rates increase with evolution of the muddy tidal flat. The exclusive strata structure of alternate muddy laminae and silty laminae originated from dynamic depositional processes on muddy tidal flat was a great obstacle to vertical migration of dissolved materials, and SOM turnover was then constrained. The muddy tidal flat processes exerted direct influences on sequestration and turnover of SOM in the salt marsh, and had great constraints on the spatial and temporal characteristics of SOM turnover of the Chongmingdongtan Salt Marsh in the Yangtze River estuary.
基金The National Natural Science Foundation of China under contract No.41171389the Public Science and Technology Research Funds Projects of Ocean under contract No.201305043Program for Liaoning Excellent Talents in University under contract No.LR2013035
文摘The effects of nitrogen (N) addition on microbial biomass, bacterial abundance, and community composition in sediment colonized by Suaeda heteroptera were examined by chloroform fumigation extraction method, real-time quantitative polymerase chain reaction, and denaturing gradient gel electrophoresis (DGGE) in a salt marsh located in Shuangtai Estuary, China. The sediment samples were collected from plots treated with different amounts of a single N fertilizer (urea supplied at 0.1, 0.2, 0.4 and 0.8 g/kg (nitrogen content in sediment) and different forms of N fertilizers (urea, (NH4)2SO4, and NH4NO3, each supplied at 0.2 g/kg (calculated by nitrogen). The fertilizers were applied 1-4 times during the plant-growing season in May, luly, August, and September of 2013. Untreated plots were included as a control. The results showed that both the amount and form of N positively influenced microbial biomass carbon, microbial biomass nitrogen, and bacterial abundance. The DGGE profiles revealed that the bacterial community composition was also affected by the amount and form of N. Thus, our findings indicate that short-term N amendment increases microbial biomass and bacterial abundance, and alters the structure of bacterial community.
基金The Science and Technology Department of Shanghai under contract Nos 08231200705, 07DZ12038 and 072312032the National Natural Science Foundation of China under contract No. 40876044
文摘To obtain information on food web structure in salt marshes of the Changjiang (Yangtze) River Estuary, the ( δ3C and δ15N values of primary producers and consumers were determined. The mean δ13C values of 31 dominant consumers ranged from -23.13‰ to -14.37‰. Except for several species ( Eriocheir sinensis, Sinonovacula constricta and Potamocorbula ustulata), consumers had interme- diate δ13C values between those of benthic microalgae and Spartina alterniflora. The mean δ15N values of 31 dominant consumers varied between 6.87‰ and 13.33‰, which indicate three trophic levels in salt marshes of the Changjiang River Estuary. A total of 18 macroinvertebrates species and four fish species represented primary consumers with trophic levels ranging from 2.0 to 2.7. Secondary consumers included two maeroinvertebrates and seven fishes with trophic levels varying between 3.0 and 3.9. The consumers were divided into three trophic guilds, i.e., detritivorous/algae feeders, omnivores and carnivores. The detrital food chain was the main energy flow pathway in the salt marsh food web of the Changjiang River Estuary, and the marsh vascular plants were at least as equally important as microphytobenthos for secondary production. The important trophic function of the salt marsh habitats in the estuary is revealed.
基金Project of the Limnic Foundation of the Chinese Academy of Sciences, ZKHZ-2-3
文摘In western Songnen Plain of China, the saline-alkaline degree of water bodies is high in salt marsh wetlands. Generally, pH is above 8.0, and the hydrochemical types belong to HCO3 2?-Na+. Through analysis on the basic saline variables such as CO3 2?, HCO3 2?, Cl?, Ca2+, Mg2+, SO4 2?, Na+, and the derivative variables such as SAR, SDR, RSC, SSP, the relationships between different variables are found, and the discriminant equations are established to identify different saline-alkaline water bodies by using principal component analysis.
基金Project supported by the National Natural Science Foundation of China (Nos.30370235 and 30670330)Science and Technology Commission of Shanghai (No.04DZ19304)Ministry of Education of China (No.105063)
基金Program Strategic Scientific Alliances between China and the Netherlands under contract No.2008DFB90240Open Research Fund Program for State Key Laboratory of Estuarine and Coastal Research under contract No.SKLEC201207Open Research Fund Program for Shandong Province Key Laboratory of Marine Ecology Environment and Disaster Prevention under contract No.2012011
文摘The analysis of vegetation-environment relationships has always been a study hotspot in ecology. A number of biotic, hydrologic and edaphic factors have great influence on the distribution of macrophytes within salt marsh.Since the exotic species Spartina alterniflora(S. alterniflora) was introduced in 1995, a rapid expansion has occurred at Chongming Dongtan Nature Reserve(CDNR) in the Changjiang(Yangtze) River Estuary, China.Several important vegetation-environment factors including soil elevation, tidal channels density(TCD),vegetation classification and fractional vegetation cover(FVC) were extracted by remote sensing method combined with field measurement. To ignore the details in interaction between biological and physical process,the relationship between them was discussed at a large scale of the whole saltmarsh. The results showed that Scirpus mariqueter(S. mariqueter) can endure the greatest elevation variance with 0.33 m throughout the marsh in CDNR. But it is dominant in the area less than 2.5 m with the occurrence frequency reaching 98%. S. alterniflora has usually been found on the most elevated soils higher than 3.5 m but has a narrow spatial distribution. The rapid decrease of S. mariqueter can be explained by stronger competitive capacity of S. alterniflora on the high tidal flat. FVC increases with elevation which shows significant correlation with elevation(r=0.30, p〈0.001). But the frequency distribution of FVC indicates that vegetation is not well developed on both elevated banks near tidal channels from the whole scale mainly due to tidal channel lateral swing and human activities. The significant negative correlation(r=–0.20, p〈0.001) was found between FVC and TCD, which shows vegetation is restricted to grow in higher TCD area corresponding to lower elevation mainly occupied by S. mariqueter communities. The maximum occurrence frequency of this species reaches to 97% at the salt marsh with TCD more than 8 m/m2.
基金Under the auspices of National Key R&D Program of China(No.2017YFC0505906)National Natural Science Foundation of China(No.51639001,51379012)Interdiscipline Research Funds of Beijing Normal University
文摘Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P < 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P > 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.
文摘Salt marshes are among the most common morphological features found in tidal landscapes and provide ecosystem services of primary ecological and economic importance.However,the continued rise in relative sea level and increasing anthropogenic pressures threaten the sustainability of these environments.The alarmingly high rates of salt marsh loss observed worldwide,mainly dictated by the lateral erosion of their margins,call for new insights into the mutual feedbacks among physical,biological,and morphological processes that take place at the critical interface between salt marshes and the adjoining tidal flats.We combined field measurements,remote sensing data,and numerical modeling to investigate the interplays between wind waves and the morphology,ecology,and planform evolution of salt marsh margins in the Venice Lagoon of Italy.Our results confirm the existence of a positive linear relationship between incoming wave power density and rates of salt marsh lateral retreat.In addition,we show that lateral erosion significantly decreases when halophytic vegetation colonizes the marsh margins,and that different erosion rates in vegetated margins are associated with different halophytes.High marsh cliffs and smooth shorelines are expected along rapidly eroding margins,whereas erosion rates are reduced in gently sloped,irregular edges facing shallow tidal flats that are typically exposed to low wind-energy conditions.By highlighting the relationships between the dynamics and functional forms of salt marsh margins,our results represent a critical step to address issues related to conservation and restoration of salt marsh ecosystems,especially in the face of changing environmental forcings.
文摘In this study, we examined the influence of changes in the degree and frequency of disturbance in estuarine tidal flats on the annual salt marsh plant communities (Suaeda maritima, Artemisia fukudo) in Mie Prefecture, Japan. Suaeda maritima and Artemisia fukudo communities occur in the branch river of the Kushida River. Although the areas occupied by these communities were very small in 2006, the Suaeda maritima community expanded significantly to 3609 m2 in 2008, and the Artemisia fukudo community expanded significantly to 2726 m2 in 2008 and 10,396 m2 in 2010. Before the onset of the investigation period in 2006, the overflow warning water level (3.5 m) and the flood fighting corps standby water level (3.0 m) each occurred on one day in August 2004 and October 2004, respectively;at those times, the water volume exceeded 1000 m3·s-1 and 1500 m3·s-1, respectively. We suggest that because much of the estuarine tidal flat erodes when the water volume exceeds 1000 m3·sǃ, the establishment of the Suaeda maritima and Artemisia fukudo communities is delayed until sufficient substrate is formed by the deposition of new sediment. In contrast, a water level of 2 - 3 m was observed on one day each in 2005, 2007 and 2009, with average water volumes of 488.5, 566.4 and 690.1 m3·s-1, respectively. We suggest that following the repeated disturbances caused by water levels of 1 - 3 m and flow volumes of 500 - 700 m3·s-1 over the bare ground exposed after flooding and erosion, Suaeda maritima is a pioneer species that colonizes on bare ground deposited by sediment transported from upstream and the sea during high tides, and following the same level of disturbance, Artemisia fukudo is secondary colonizer that has germinated and grown on the sediment deposited on the Suaeda maritima community.
基金the National Natural Science Foundation of China (Nos.40401059 and 40576040).
文摘During the past century,natural and human modifications of environmental systems have greatly accelerated coastal salt marsh deterioration and shoreline retreat in many regions worldwide. Field investigation,profile analysis,geographical information analysis,and remote sensing were employed in combination to study the effect of sediment on Spartina alterniflora salt marshes of the coast in Jiangsu Province,East China. The results indicated that the propagation of Spartina alterniflora salt marshes was closely related to regional sediment conditions,especially the supply of fine-grained materials. Additionally,because of the dense and high grass in Spartina alterniflora salt marshes,wave energy and tidal currents were baffled and weaker than those of the adjacent,unvegetated mud flats. Fine sediment was hardly resuspended under the low energy conditions in the Spartina alterniflora salt marshes.
基金supported by the grant from the Postdoctoral Advance Programs of Zhejiang Province and Scientific Project Establishment of Huadong Engineering Corporation Limited(No.KY2020-SD-11).
文摘Coastal wetlands are the most productive ecosystems worldwide and can provide important ecosystem services,yet the characteristics of microbial community within these systems remain poorly understood.Microbial community of salt marsh vegetation and the associated soil physio-chemical properties were investigated in this study.Three typical Suaeda australis,Phragmites australis,Spartina alterniflora wetlands,and non-vegetated bare mudflats in the Zhoushan Islands were studied to advance the understanding of the characteristics of soil bacterial communities in coastal wetlands.Results showed that the bare mudflats exhibited high pH value and soil moisture content compared with the vegetated samples.In different vegetation types,the organic matter content,total nitrogen,and total potassium content decreased in the order:S.alterniflora wetland>P.australis wetland>S.australis wetland,and there was no obvious difference in total phosphorous content.The halophytes could decrease soil salinity compared with bare mudflats.Proteobacteria,Nitrospinae,Bacteroidetes,Acidobacteria,and Nitrospirae were the predominant level across all samples.Functional prediction showed that SPA-covered soil might play vital roles in sulphur cycling,while SUA and PHR covered soils were involved in nitrogen cycling.This study could provide the first insight into the microbial community of this study area and contribute to a better understanding of vegetation microbiota and bioremediation in coastal wetland ecosystem.
基金Supported by the Natural Science Foundation of Shanghai(No.19ZR1415300)the Zhejiang Provincial Natural Science Foundation of China(No.LQ21D060005)the China Postdoctoral Science Foundation(No.2020M681931)。
文摘Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.
基金The National Key Technology Research and Development Program of the Ministry of Science and Technology of China under contract No.2012BAC07B01the National Natural Science Foundation of China under contract Nos 41371024,41230751 and 41071006
文摘Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this study,we explored the changes of tidal flat and salt marsh coverage in a small-scale tidal flat with an area of ~160 000 m^2 in the plain coast of Jiangsu Province,China.Human activities(e.g.,the construction of dikes) are a crucial contributor that benefits for the tidal flat accretions and the following changes of salt marsh coverage.Located in the front of the man-made "concave coastline",the study area is suitable for sediment accretion after the dike construction in the end of 2006.On the basis of the annual tidal surface elevation survey from 2007 to 2012,the sedimentation rates in the human influenced tidal flat varied from a few centimeters per year to 23 cm/a.The study area experienced a rapid accretion in the tidal flat and the expansion of the salt marsh,with the formation of a longshore bar,and a subsequent decline of the salt marsh.Breaking waves during the flooding tide brought much sediment from the adjacent tidal flat to the study area,which caused burial and degeneration of the salt marsh.The vertical grain size changes within a 66 cm long core in the study area also demonstrated the above changes in the tidal environment.This study indicates that the responses of small-scale tidal flat changes to reclamation are significant,and the rational reclamation would benefit for the new salt marsh formation in front of the dikes.Further research about the evolution of small scale tidal flat as well as the spatial planning of the polder dike should be strengthened for the purpose to maintain a healthier coastal environment.
基金Under the auspices of the National Key R&D Program of China(No.2017YFC0505906)the National Natural Science Foundation of China(No.51639001,51379012)the Interdiscipline Research Funds of Beijing Normal University
文摘Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.
基金Supported by Special Research Fund for the National Non-profit Institutes (East China Sea Fisheries Research Institute) (No.2007M03) and Administration Bureau of Virescence of Shanghai Municipality
文摘Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year.A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected.Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%),Collichthys lucidus (18.6%),Periophthalmus magnuspinnatus (18.2%),Liza haematocheilus (17.9%),and secondarily by Mugilogobius abei (8.5%),L.carinatus (7.2%),Odontamblyopus lacepedii (4.3%),and Acanthogobius ommaturus (3.9%);another 18 species were present only occasionally.Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek.In spring,the communities were dominated by B.pectinirostris,P.magnuspinnatus,C.lucidus and M.abei;in summer,autumn,and winter by L.haematocheilus,L.carinatus,A.ommaturus and O.lacepedii.Some species showed strong habitat selection;L.carinatus and P.magnuspinnatus were distributed mainly in the upper and middle creek,while B.pectinirostris,M.abei and O.lacepedii inhabited the middle and lower creek.The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.
基金The National Natural Science Foundation of China under contract Nos 40901010 and 40730526Leading Academic Discipline Project of Shanghai Normal University under contract No.DZL809
文摘Between April 2002 and April 2003,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Changjiang (Yangtze) Estuary under different weather conditions.Cross-shore suspended sediment flux was calculated and analyzed.The results show that under calm weather conditions,the current velocity process in bald field and salt marsh area varied differently during semidiurnal tidal cycles.Owing to current velocity asymmetry,mean SSC during flood tide phase was 1.8 times higher than that of ebb tide phase.As a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally accreting.There was significant positive correlation between total sediment flux and quartic power of maximum water depth.It indicates that tidal ranges dominate suspended sediment transport and sedimentation process in the salt marsh pioneer zone under the calm weather condition.The sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stable accreting of salt marsh towards the sea.The wind events enhanced SSC and current velocity during the semidiurnal tides.And the remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.
文摘The Tuckerton Peninsula, a large expanse (~2000 ha) of highly inundated Spartina alterniflora salt marsh habitat, forms one of the most extensive coastal wetland systems in New Jersey (USA). It is projected to be among the first salt marsh systems in New Jersey to be lost by rising sea level driven by climate change. The changes that occur in the demographic, ecologic, and ecogeomorphic characteristics of the salt marsh habitat at this location will be vital to understanding future habitat change in coastal wetlands in the Mid-Atlantic region. As a consequence, the Tuckerton Peninsula salt marsh system is designated as a sentinel site of the Jacques Cousteau National Estuarine Research Reserve (JCNERR) for the detection, monitoring, and assessment of climate change effects, most notably sea-level rise and inundation. Development of the Tuckerton Peninsula as a sentinel site requires a high accuracy local geodetic control network to connect existing water quality monitoring stations, vegetation transects and monitoring surface elevation tables, ground water wells, and digital elevation models on the same vertical datum. The integration of these monitoring infrastructure components is crucial to effective operation of the sentinel site. It will enable the collection of essential data to assess rates of marsh migration and upland transgression, as well as delineate key natural and anthropogenic drivers influencing habitat condition and change. The JCNERR sentinel site designation supports the National Oceanic and Atmospheric Administration’s long-term goal of assessing coastal vulnerability in the USA to climate change and generating data useful for forging climate adaptation and mitigation initiatives for coastal communities. Habitat and vertical control data collected at this sentinel site will be made available to decision makers across the nation and will enable them to determine how the loss of critical salt marsh habitat will affect coastal communities, their adaptation to future habitat loss, and their development of mitigation plans to address impacts and enhance resiliency.