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
The Gelsari and Lentini marshes, in east-central Sicily, are wetland under heavy anthropogenic pressure. This area is regularly subjected to water withdrawals and agriculture is practiced. Periodic bird census activit...The Gelsari and Lentini marshes, in east-central Sicily, are wetland under heavy anthropogenic pressure. This area is regularly subjected to water withdrawals and agriculture is practiced. Periodic bird census activities had been conducted in this area between 2016 and 2022 with collected data being supplemented with the data from a previous survey conducted between 2010 and 2016. During the censuses, numerous photographs were collected, which were later used for counts. In total, 121 surveys were carried out, with visits occurring approximately 20 times per year, covering all seasons. The data collected, both from bibliography and unpublished observations, were organised in table. 120 species and subspecies have been reported, 41 of which are in Annex I of the Birds Directive. Between 2021 and 2022, a water column measurement was taken in a central area of the Lentini marsh and compared with rainfall data in the area. It was found that water removal, occurring in both marshes in different modes, produced different effects on habitat conservation. Of the two marshes, Lentini is the one in which the existing favorable conditions in its most depressed areas, located below sea level, have allowed for the adequate conservation of the wetland. This environmental improvement having occurred with respect to the previous period has restored to the marsh its historically recognized possibility of not drying up completely during the summer period, allowing permanence of numerous birds. The obtained results suggest total elimination of agriculture and discontinuation of water withdrawals in the Lentini marsh as well as regulation of withdrawals in the Gelsari marsh.展开更多
The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From t...The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From their headwater sources in the mountains of eastern Iran, these rivers descend through valleys and gorges and flow into the plains of Iran. The Shatt al-Arab River drains an area of 879,790 square kilometers which includes land in Iran, Syria, Türkiye, Kuwait, and Iraq. The Karun joins Shatt al-Arab 110 km downriver from the confluence of the Euphrates and Tigris Rivers and flows 85 km into the Persian Gulf. The Karun river flows in a southwestern direction through the central plain and provides about 10 per cent of the water balance of Iran’s largest wetland, the Shadegan, which includes permanent marshes, lakes, and riparian habitats. The article summarizes a vast array of publications on the stated topic and this civilizationally important region in order to draw additional attention to its interdependent environmental, economic and political problems the successful resolution of which is only possible with the participation of the entire research community.展开更多
The structure and diversity of the bacterial communities in rhizosphere soils of native Phragmites australis and Scirpus rnariqueter and alien Spartina alterniflora in the Yangtze River Estuary were investigated by co...The structure and diversity of the bacterial communities in rhizosphere soils of native Phragmites australis and Scirpus rnariqueter and alien Spartina alterniflora in the Yangtze River Estuary were investigated by constructing 16S ribosomal DNA (rDNA) clone libraries. The bacterial diversity was quantified by placing the clones into operational taxonomic unit (OTU) groups at the level of sequence similarity of 〉 97%. Phylogenetic analysis of the resulting 398 clone sequences indicated a high diversity of bacteria in the rhizosphere soils of these plants. The members of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria of the phylum Proteobacteria were the most abundant in rhizobacteria. Chao 1 nonpaxametric diversity estimator coupled with the reciprocal of Simpson's index (l/D) was applied to sequence data obtained from each library to evaluate total sequence diversity and quantitatively compare the level of dominance. The results showed that Phragmites, Scirpus, and Spartina rhizosphere soils contained 200, 668, and 382 OTUs, respectively. The bacterial communities in the Spartina and Phragraites rhizosphere soils displayed species dominance revealed by 1/D, whereas the bacterial community in Scirpus rhizosphere soil had uniform distributions of species abundance. Overall, analysis of 16S rDNA clone libraries from the rhizosphere soils indicates that the changes in bacterial composition may occur concomitantly with the shift of species composition in plant communities.展开更多
Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 y...Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 years and projected for the near future. The distr/bution patterns and development mechanisms of the permafrost and marshes have been examined both in theories and in field observations, in order to better understand the symbiosis of permafrost and marshes. The permafrost and marshes in the Da and Xiao Hinggan Mountains display discernible zonations in latitude and elevation. The marsh vegetation canopy, litter and peat soil have good thermal insulation properties for the underlying permafrost, resulting in a thermal offset of 3 ℃ to 4℃ and subsequently suppressing soil temperature. In addition, the much higher thermal conductivity of frozen and ice-rich peat in the active layer is conducive to the development or in favor of the protection of permafrost due to the semi-conductor properties of the soils overlying the permafrost. On the other hand, because permafrost is almost impervious, the osmosis of water in marsh soils can be effectively reduced, timely providing water supplies for helophytes growth or germination in spring. In the Da and Xiao Hinggan Mountains, the permafrost degradation has been accelerating due to the marked climate warming, ever increasing human activities, and the resultant eco-environmental changes. Since the permafrost and marsh environments are symbiotic and interdependent, they need to be managed or protected in a well-coordinated and integrated way.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
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
Wetlands at the interface of the terrestrial and aquatic ecosystems are intensive sites for mineralization of organic matter, but the contribution of winter season fluxes of CH4, CO2 and N2O from wetland ecosystems to...Wetlands at the interface of the terrestrial and aquatic ecosystems are intensive sites for mineralization of organic matter, but the contribution of winter season fluxes of CH4, CO2 and N2O from wetland ecosystems to annual budgets is poorly known. By using the static opaque chamber and GC techniques, fluxes of CH4, CO2 and N2O at two freshwater marshes in the Sanjiang Plain were measured during the winter seasons of 2002/2003 and 2003/2004 with contrasting snow conditions and flooding regimes. The results showed that there were significant interannual and spatial differences in CH4, CO2 and N2O fluxes. The Carex lasiocarpa marsh emitted more CH4 and CO2 while absorbed less N2O than the Deyeuxia angustifolia marsh during the winter seasons. Over the winter season, emissions of CH4, CO2 and N2O ranged from 0.42 to 2.41 gC/m^2, from 24.13 to 50.16 gC/m^2, and from -25,20 to -148.96 mgN/m^2, respectively. The contributions of winter season CH4 and CO2 emission to the annual budgets were 2.32% 4.62% and 22.17%- 27.97%, respectively. Marshes uptake N2O during the freezing period, while release N2O during the thawing period. The winter uptake equaled to 13.70%-86.69% of the growing-season loss. We conclude that gas exchange between soil/snow and the atmosphere in the winter season contributed greatly to the annual budgets and cannot be ignored in a cool temperate freshwater marsh in Northeast China.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
Indices of Biological Integrity (IBIs) are being increasingly used as useful and direct tools for assessing general health of aquatic ecosystems. Although such ecosystems in Iraq, especially the southern marshes, unde...Indices of Biological Integrity (IBIs) are being increasingly used as useful and direct tools for assessing general health of aquatic ecosystems. Although such ecosystems in Iraq, especially the southern marshes, underwent severe alterations during the last two decades, including extensive desiccation in the 1990s, such tools are largely lacking. Phytoplankton Index of Biological Integrity (P-IBI) was developed from data collected seasonally from 2005 up to 2007 in different sites of the southern marshes of Iraq to evaluate the trend of these ecosystems based on phytoplankton data. Ten metrics were selected for measuring P-IBI for the first time in Iraq as a proposed project from Nature Iraq and Twin Rivers Institute, American University of Iraq-Sulaimani. Although generally fluctuated both spatially and temporally, mean P-IBI scores showed better conditions in Al Hawizeh marsh (Good) as compared to the Central and West & East Al Hammar marshes (Fair to Good). However, the results generally indicated evidence of improvement at the Central and West & East Al Hammar marshes, whereas no recovery of the status of water was evident throughout the data obtained at Al Hawizeh marsh. Values were generally higher in winter. These observations clearly reflect the relative stability of the Hawizeh marsh ecosystem which was not subject to the desiccation process in the 1990s, while the severely dried systems of the Central and Hammar marshes are showing positive responses to the restoration efforts that were started after 2003. Among the ten metrics comprising the index, relative abundance of diatoms had the most prominent effect on the P-IBI value in the three marshes. Metrics such as chlorophyll- a concentration and relative abundance of Cyanophyta and Chlorophyta also played a significant role in determining the index value. Continuous monitoring based on the selection of the most suitable metrics is recommended.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
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
Insects such as Acheta domesticus account for over half of marsh fish and migratory bird diet. Therefore, insects are very important to marsh and island ecosy stems and are susceptible to oil contamination, but little...Insects such as Acheta domesticus account for over half of marsh fish and migratory bird diet. Therefore, insects are very important to marsh and island ecosy stems and are susceptible to oil contamination, but little research has been done to study the effects of oil spills on cricket populations. The purpose of this experiment was to determine the effects of an oil spill event on Acheta domesticus mortality and hatch rate to establish environmental sustainability. The treatment groups included 0% oil contamination, 5% oil contamination and 10% oil contamination. The scientist counted the number of deaths in two-week, four-week, and six-week-old crickets after oil contamination. In addition, the scientist counted the number of hatchlings among treated cricket eggs. Error bar lines in the results section supported the scientist’s hypothesis that the crickets would be affected by oil contamination. In fact, over 90% of the 10% oil treatment group died and over 80% of the 5% oil treatment group died after five days of oil contamination in the six-week-old experiment. The scientist used a Gas Chromatography Mass Spectrometer to determine if benzene, toluene, ethylbenzene, or xylene (total) were present in the sediment samples. BTEX exposure is suspected to possibly cause insect mortality. These volatile organic compounds were present in the samples and were found in higher quantities in samples with higher concentrations of oil. The highest quantity of volatile organic compounds present was xylene. After studying the population dynamics of the tested Acheta domesticus, the scientist found that the two-week and four-week-old crickets’ survivability could fit a linear model while the six-week-old crickets fit an exponential model. The scientist used these models to observe how long it took each treatment group to approach zero, and the oiled groups grew closer to a population of zero significantly faster. For example, it took about twenty-seven days for the 10% treatment group’s population to approach zero whereas the control, 0% treatment group, took about seven days in the two-week-old cricket experiment. Overall, the six-week-old crickets had the highest mortality, and the cricket egg experiment resulted in extremely low hatch rate. Specifically, the highest number of crickets that hatched in an oiled replication either 5% or 10% oil was eight out of the five thousand eggs laid. Since the adult crickets are the most physically able to reproduce and the cricket eggs had low hatch rates, the cricket population would significantly decrease after an oil spill with 5% or more soil contamination. However, if the plant matter that crickets consume is still present in their environment, they may be able to recover.展开更多
Both Arc GIS 9.2 and ERDAS 9.1 software were used to analyze the concentrations in radiation exposure of marshlands in southern Iraq during June 2009 and January 2010. It was measured radiation exposure rates above th...Both Arc GIS 9.2 and ERDAS 9.1 software were used to analyze the concentrations in radiation exposure of marshlands in southern Iraq during June 2009 and January 2010. It was measured radiation exposure rates above the soil and water surface, and also measured radioactivity in the environmental models (soil, plants, sediment and water) for all the selected sites of the study area. Furthermore, it has" been measuring the level of radioactive contamination concentration of the isotope Bi-214 and Ac-228 and K-40 as well as peer-Cs-137-resulting from the operations of nuclear fission and measured the background radiation compared with other regions. Environmental samples (soil-water-plant-deposits) were taken and measuring the concentration ratio of radioisotopes in using the system account gentle rays Kama multi-channel and using the counter--Nal-tinged element--thallium--Type-WIZARD-1470 as well as a LB 1200. The results showed the regions of the marshes of radioactive contamination now.展开更多
Water quality of the East Hammar marsh after restoration was assessed by using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI).The model was applied in two approaches based on the h...Water quality of the East Hammar marsh after restoration was assessed by using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI).The model was applied in two approaches based on the historical data and the CCME aquatic life guidelines as objectives. Variables included in the index calculation were Water Temperature, Dissolved Oxygen, Salinity, pH value, Total Nitrogen, Ammonia, Nitrate, Phosphorus and Sodium. The CCME WQI analysis in both approaches reflected that water quality of the East Hammar marsh is rated as poor based on 2005-2006 data, meaning that the conditions of the marsh are often depart from natural or desirable levels particularly in respect to sodium and nitrogenous compounds;it simply has not recovered yet. The results reflect that the marsh area is still far from the current guideline criteria and, too far from restoration.展开更多
Preventing water flow through the marshes in southern Iraq was a policy of the previous regime in Iraq during 1990’s. This phenomena lead to tremendous structural changes in ecosystems, however after 2003 rehabilitat...Preventing water flow through the marshes in southern Iraq was a policy of the previous regime in Iraq during 1990’s. This phenomena lead to tremendous structural changes in ecosystems, however after 2003 rehabilitation policy applied to the area was implementd in order to re-establish marshes ecosystems. In this study, a zooplankton Index of Biotic Integrity (Z-IBI) was measured for the first time in different sites in the Iraqi marshes. The following eight metrics were used: zooplankton ratio, relative abundance of Calanoid, relative abundance of Cyclopoid, relative abundance of Cladocera, relative abundance of Rotifera, biomass of tolerant species, biomass of sensitive species, and ratio of zooplankton biomass to phytoplankton biomass. Results of application of Z-IBI on the Iraqi marshes in this study indicate a slight improvement of water quality in the central marshes and degradation in other parts of the marshes. This work may fill part of the existing research gap in the application of the IBI index in Iraqi inland waters to illustrate the effects of previous deterioration in water quality.展开更多
Wood treated with chromated copper arsenate (CCA) is a common material for pier pilings. Research on CCA impacts in estuarine systems indicates that the magnitude of the biological effect is variable and dependent o...Wood treated with chromated copper arsenate (CCA) is a common material for pier pilings. Research on CCA impacts in estuarine systems indicates that the magnitude of the biological effect is variable and dependent on sediment and water characteristics. To assist environmental agencies in assessing pier impacts a project was conducted in the U.S.A. to investigate the spatial distribution and magnitude of As, Cr, and Cu accumulation in waters and soils near old and new piers. For new piers, soluble metal levels were highest within 2.9 m of the piers. Total As and Cu levels approached background levels at distances of 2.9 m and 1.4 m, respectively. For old piers, total As and Cu approached background levels at a distance of 9.0 m. Total Cr never exceeded background levels. Threshold effects concentrations were exceeded by sedimented As and Cu within 3.6 m of old piers and 2.1 m of new piers. Apparent effects thresholds were never reached. The only water chemistry variable impacted by piers was As with new piers. It was concluded that leachates accumulate only close to piers and at levels below critical biological thresholds, and would be expected to have negligible ecological effects in reasonably flushed areas.展开更多
Elements (vanadium and zinc) were determined in the two most abundant species of shell mollusks (Unio tigridis and Fiviparous bengalensis) and the water where they live in five stations in the Iraqi marshes. The s...Elements (vanadium and zinc) were determined in the two most abundant species of shell mollusks (Unio tigridis and Fiviparous bengalensis) and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation (P = 0.224) for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.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.
文摘The Gelsari and Lentini marshes, in east-central Sicily, are wetland under heavy anthropogenic pressure. This area is regularly subjected to water withdrawals and agriculture is practiced. Periodic bird census activities had been conducted in this area between 2016 and 2022 with collected data being supplemented with the data from a previous survey conducted between 2010 and 2016. During the censuses, numerous photographs were collected, which were later used for counts. In total, 121 surveys were carried out, with visits occurring approximately 20 times per year, covering all seasons. The data collected, both from bibliography and unpublished observations, were organised in table. 120 species and subspecies have been reported, 41 of which are in Annex I of the Birds Directive. Between 2021 and 2022, a water column measurement was taken in a central area of the Lentini marsh and compared with rainfall data in the area. It was found that water removal, occurring in both marshes in different modes, produced different effects on habitat conservation. Of the two marshes, Lentini is the one in which the existing favorable conditions in its most depressed areas, located below sea level, have allowed for the adequate conservation of the wetland. This environmental improvement having occurred with respect to the previous period has restored to the marsh its historically recognized possibility of not drying up completely during the summer period, allowing permanence of numerous birds. The obtained results suggest total elimination of agriculture and discontinuation of water withdrawals in the Lentini marsh as well as regulation of withdrawals in the Gelsari marsh.
文摘The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From their headwater sources in the mountains of eastern Iran, these rivers descend through valleys and gorges and flow into the plains of Iran. The Shatt al-Arab River drains an area of 879,790 square kilometers which includes land in Iran, Syria, Türkiye, Kuwait, and Iraq. The Karun joins Shatt al-Arab 110 km downriver from the confluence of the Euphrates and Tigris Rivers and flows 85 km into the Persian Gulf. The Karun river flows in a southwestern direction through the central plain and provides about 10 per cent of the water balance of Iran’s largest wetland, the Shadegan, which includes permanent marshes, lakes, and riparian habitats. The article summarizes a vast array of publications on the stated topic and this civilizationally important region in order to draw additional attention to its interdependent environmental, economic and political problems the successful resolution of which is only possible with the participation of the entire research community.
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)
文摘The structure and diversity of the bacterial communities in rhizosphere soils of native Phragmites australis and Scirpus rnariqueter and alien Spartina alterniflora in the Yangtze River Estuary were investigated by constructing 16S ribosomal DNA (rDNA) clone libraries. The bacterial diversity was quantified by placing the clones into operational taxonomic unit (OTU) groups at the level of sequence similarity of 〉 97%. Phylogenetic analysis of the resulting 398 clone sequences indicated a high diversity of bacteria in the rhizosphere soils of these plants. The members of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria of the phylum Proteobacteria were the most abundant in rhizobacteria. Chao 1 nonpaxametric diversity estimator coupled with the reciprocal of Simpson's index (l/D) was applied to sequence data obtained from each library to evaluate total sequence diversity and quantitatively compare the level of dominance. The results showed that Phragmites, Scirpus, and Spartina rhizosphere soils contained 200, 668, and 382 OTUs, respectively. The bacterial communities in the Spartina and Phragraites rhizosphere soils displayed species dominance revealed by 1/D, whereas the bacterial community in Scirpus rhizosphere soil had uniform distributions of species abundance. Overall, analysis of 16S rDNA clone libraries from the rhizosphere soils indicates that the changes in bacterial composition may occur concomitantly with the shift of species composition in plant communities.
基金Under the auspices of National Natural Science Foundation of China (No. 40701031,40225001,J0630966)3rd-term Knowledge Innovation Program of Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences (No. O650445)
文摘Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 years and projected for the near future. The distr/bution patterns and development mechanisms of the permafrost and marshes have been examined both in theories and in field observations, in order to better understand the symbiosis of permafrost and marshes. The permafrost and marshes in the Da and Xiao Hinggan Mountains display discernible zonations in latitude and elevation. The marsh vegetation canopy, litter and peat soil have good thermal insulation properties for the underlying permafrost, resulting in a thermal offset of 3 ℃ to 4℃ and subsequently suppressing soil temperature. In addition, the much higher thermal conductivity of frozen and ice-rich peat in the active layer is conducive to the development or in favor of the protection of permafrost due to the semi-conductor properties of the soils overlying the permafrost. On the other hand, because permafrost is almost impervious, the osmosis of water in marsh soils can be effectively reduced, timely providing water supplies for helophytes growth or germination in spring. In the Da and Xiao Hinggan Mountains, the permafrost degradation has been accelerating due to the marked climate warming, ever increasing human activities, and the resultant eco-environmental changes. Since the permafrost and marsh environments are symbiotic and interdependent, they need to be managed or protected in a well-coordinated and integrated way.
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.
文摘Wetlands at the interface of the terrestrial and aquatic ecosystems are intensive sites for mineralization of organic matter, but the contribution of winter season fluxes of CH4, CO2 and N2O from wetland ecosystems to annual budgets is poorly known. By using the static opaque chamber and GC techniques, fluxes of CH4, CO2 and N2O at two freshwater marshes in the Sanjiang Plain were measured during the winter seasons of 2002/2003 and 2003/2004 with contrasting snow conditions and flooding regimes. The results showed that there were significant interannual and spatial differences in CH4, CO2 and N2O fluxes. The Carex lasiocarpa marsh emitted more CH4 and CO2 while absorbed less N2O than the Deyeuxia angustifolia marsh during the winter seasons. Over the winter season, emissions of CH4, CO2 and N2O ranged from 0.42 to 2.41 gC/m^2, from 24.13 to 50.16 gC/m^2, and from -25,20 to -148.96 mgN/m^2, respectively. The contributions of winter season CH4 and CO2 emission to the annual budgets were 2.32% 4.62% and 22.17%- 27.97%, respectively. Marshes uptake N2O during the freezing period, while release N2O during the thawing period. The winter uptake equaled to 13.70%-86.69% of the growing-season loss. We conclude that gas exchange between soil/snow and the atmosphere in the winter season contributed greatly to the annual budgets and cannot be ignored in a cool temperate freshwater marsh in Northeast China.
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.
文摘Indices of Biological Integrity (IBIs) are being increasingly used as useful and direct tools for assessing general health of aquatic ecosystems. Although such ecosystems in Iraq, especially the southern marshes, underwent severe alterations during the last two decades, including extensive desiccation in the 1990s, such tools are largely lacking. Phytoplankton Index of Biological Integrity (P-IBI) was developed from data collected seasonally from 2005 up to 2007 in different sites of the southern marshes of Iraq to evaluate the trend of these ecosystems based on phytoplankton data. Ten metrics were selected for measuring P-IBI for the first time in Iraq as a proposed project from Nature Iraq and Twin Rivers Institute, American University of Iraq-Sulaimani. Although generally fluctuated both spatially and temporally, mean P-IBI scores showed better conditions in Al Hawizeh marsh (Good) as compared to the Central and West & East Al Hammar marshes (Fair to Good). However, the results generally indicated evidence of improvement at the Central and West & East Al Hammar marshes, whereas no recovery of the status of water was evident throughout the data obtained at Al Hawizeh marsh. Values were generally higher in winter. These observations clearly reflect the relative stability of the Hawizeh marsh ecosystem which was not subject to the desiccation process in the 1990s, while the severely dried systems of the Central and Hammar marshes are showing positive responses to the restoration efforts that were started after 2003. Among the ten metrics comprising the index, relative abundance of diatoms had the most prominent effect on the P-IBI value in the three marshes. Metrics such as chlorophyll- a concentration and relative abundance of Cyanophyta and Chlorophyta also played a significant role in determining the index value. Continuous monitoring based on the selection of the most suitable metrics is recommended.
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Insects such as Acheta domesticus account for over half of marsh fish and migratory bird diet. Therefore, insects are very important to marsh and island ecosy stems and are susceptible to oil contamination, but little research has been done to study the effects of oil spills on cricket populations. The purpose of this experiment was to determine the effects of an oil spill event on Acheta domesticus mortality and hatch rate to establish environmental sustainability. The treatment groups included 0% oil contamination, 5% oil contamination and 10% oil contamination. The scientist counted the number of deaths in two-week, four-week, and six-week-old crickets after oil contamination. In addition, the scientist counted the number of hatchlings among treated cricket eggs. Error bar lines in the results section supported the scientist’s hypothesis that the crickets would be affected by oil contamination. In fact, over 90% of the 10% oil treatment group died and over 80% of the 5% oil treatment group died after five days of oil contamination in the six-week-old experiment. The scientist used a Gas Chromatography Mass Spectrometer to determine if benzene, toluene, ethylbenzene, or xylene (total) were present in the sediment samples. BTEX exposure is suspected to possibly cause insect mortality. These volatile organic compounds were present in the samples and were found in higher quantities in samples with higher concentrations of oil. The highest quantity of volatile organic compounds present was xylene. After studying the population dynamics of the tested Acheta domesticus, the scientist found that the two-week and four-week-old crickets’ survivability could fit a linear model while the six-week-old crickets fit an exponential model. The scientist used these models to observe how long it took each treatment group to approach zero, and the oiled groups grew closer to a population of zero significantly faster. For example, it took about twenty-seven days for the 10% treatment group’s population to approach zero whereas the control, 0% treatment group, took about seven days in the two-week-old cricket experiment. Overall, the six-week-old crickets had the highest mortality, and the cricket egg experiment resulted in extremely low hatch rate. Specifically, the highest number of crickets that hatched in an oiled replication either 5% or 10% oil was eight out of the five thousand eggs laid. Since the adult crickets are the most physically able to reproduce and the cricket eggs had low hatch rates, the cricket population would significantly decrease after an oil spill with 5% or more soil contamination. However, if the plant matter that crickets consume is still present in their environment, they may be able to recover.
文摘Both Arc GIS 9.2 and ERDAS 9.1 software were used to analyze the concentrations in radiation exposure of marshlands in southern Iraq during June 2009 and January 2010. It was measured radiation exposure rates above the soil and water surface, and also measured radioactivity in the environmental models (soil, plants, sediment and water) for all the selected sites of the study area. Furthermore, it has" been measuring the level of radioactive contamination concentration of the isotope Bi-214 and Ac-228 and K-40 as well as peer-Cs-137-resulting from the operations of nuclear fission and measured the background radiation compared with other regions. Environmental samples (soil-water-plant-deposits) were taken and measuring the concentration ratio of radioisotopes in using the system account gentle rays Kama multi-channel and using the counter--Nal-tinged element--thallium--Type-WIZARD-1470 as well as a LB 1200. The results showed the regions of the marshes of radioactive contamination now.
文摘Water quality of the East Hammar marsh after restoration was assessed by using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI).The model was applied in two approaches based on the historical data and the CCME aquatic life guidelines as objectives. Variables included in the index calculation were Water Temperature, Dissolved Oxygen, Salinity, pH value, Total Nitrogen, Ammonia, Nitrate, Phosphorus and Sodium. The CCME WQI analysis in both approaches reflected that water quality of the East Hammar marsh is rated as poor based on 2005-2006 data, meaning that the conditions of the marsh are often depart from natural or desirable levels particularly in respect to sodium and nitrogenous compounds;it simply has not recovered yet. The results reflect that the marsh area is still far from the current guideline criteria and, too far from restoration.
文摘Preventing water flow through the marshes in southern Iraq was a policy of the previous regime in Iraq during 1990’s. This phenomena lead to tremendous structural changes in ecosystems, however after 2003 rehabilitation policy applied to the area was implementd in order to re-establish marshes ecosystems. In this study, a zooplankton Index of Biotic Integrity (Z-IBI) was measured for the first time in different sites in the Iraqi marshes. The following eight metrics were used: zooplankton ratio, relative abundance of Calanoid, relative abundance of Cyclopoid, relative abundance of Cladocera, relative abundance of Rotifera, biomass of tolerant species, biomass of sensitive species, and ratio of zooplankton biomass to phytoplankton biomass. Results of application of Z-IBI on the Iraqi marshes in this study indicate a slight improvement of water quality in the central marshes and degradation in other parts of the marshes. This work may fill part of the existing research gap in the application of the IBI index in Iraqi inland waters to illustrate the effects of previous deterioration in water quality.
文摘Wood treated with chromated copper arsenate (CCA) is a common material for pier pilings. Research on CCA impacts in estuarine systems indicates that the magnitude of the biological effect is variable and dependent on sediment and water characteristics. To assist environmental agencies in assessing pier impacts a project was conducted in the U.S.A. to investigate the spatial distribution and magnitude of As, Cr, and Cu accumulation in waters and soils near old and new piers. For new piers, soluble metal levels were highest within 2.9 m of the piers. Total As and Cu levels approached background levels at distances of 2.9 m and 1.4 m, respectively. For old piers, total As and Cu approached background levels at a distance of 9.0 m. Total Cr never exceeded background levels. Threshold effects concentrations were exceeded by sedimented As and Cu within 3.6 m of old piers and 2.1 m of new piers. Apparent effects thresholds were never reached. The only water chemistry variable impacted by piers was As with new piers. It was concluded that leachates accumulate only close to piers and at levels below critical biological thresholds, and would be expected to have negligible ecological effects in reasonably flushed areas.
文摘Elements (vanadium and zinc) were determined in the two most abundant species of shell mollusks (Unio tigridis and Fiviparous bengalensis) and the water where they live in five stations in the Iraqi marshes. The study of concentrations elements was a target organ for aquatic environmental. Comparison between the mean concentrations of the elements in the water concentration levels of all studied elements was the highest with the mollusks. The results show that the station 5 is where the highest concentrations are found in water and in the two species. There is a significant correlation (P = 0.224) for concentrations of vanadium and P = 0.735 for zinc in two species of mollusks relative to their concentrations in surface water. All significant differences were accepted at a level of P 〈 0.05. The potential uptake of elements including V and Zn, as Viviparous bengalensi 〉 Unio tigridis, The mechanism for elements uptake determined by water for organisms confined to the contaminated areas seemed to be largely independent of species, mollusks demonstrated a significant positive relationship with water. These results have important implications for the utility of marshes biota as subjects for elements monitoring program.