Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature 〉 activated time 〉 impregnati...Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature 〉 activated time 〉 impregnation ratio 〉 impregnation time. The optimum condition was found at an impregnation ratio of 2.5, an impregnation time of 9 hr, an activated temperature of 500℃, and an activated time of 80 min. The Brunauer-Emmett-Teller surface area and average pore size of the activated carbon were 1279 m^2/g and 5.585 nm, respectively. A heterogeneous structure in terms of both size and shape was highly developed and widely distributed on the carbon surface. Some groups containing oxygen and phosphorus were formed, and the carboxyl group was the major oxygen-containing functional group. An isotherm equilibrium study was carried out to investigate the adsorption capacity of the activated carbon. The data fit the Langmuir isotherm equation, with maximum monolayer adsorption capacities of 192.30 mg/g for Neutral Red and 196.08 mg/g for Malachite Green. Dye-exhausted carbon could be regenerated effectively by thermal treatment. The results indicated that cattail-derived activated carbon was a promising adsorbent for the removal of cationic dyes from aqueous solutions.展开更多
At present, chlorine dioxide has been widely used as a bactericide that may become an alternative to chlorine. In this study, fresh-cut narrow-leaf cattail was soaked with 45, 70 and 95 mg/L chlorine dioxide solution,...At present, chlorine dioxide has been widely used as a bactericide that may become an alternative to chlorine. In this study, fresh-cut narrow-leaf cattail was soaked with 45, 70 and 95 mg/L chlorine dioxide solution, respectively. Fresh-cut narrow-leaf cattail samples were collected regularly to determine changes in surface microbe amount, cellulose content, Vc content, reduction sugar content and sensory quality of narrow-leaf cattail, thus analyzing the effects of chlorine diox- ide on sterilization and preservation of fresh-cut narrow-leaf cattail. The results showed that all three concentrations of chlorine dioxide solution could significantly reduce the amount of microbes on the surface of fresh-cut narrow-leaf cattail and improve the edible safety of products. The initial sterilization efficiency was im- proved gradually as the concentration of chlorine dioxide increased. In addition, chlorine dioxide treatment postponed the increase of cellulose content of fresh-cut narrow-leaf cattail. However, chlorine dioxide oxidized Vc and reducing sugar, and its bleaching effect also exerted a certain impact on the sensory quality of fresh- cut narrow-leaf cattail. Based on comprehensive comparisons, 45 - 70 mg/L chlorine dioxide solution exerted the best effects on sterilization and preservation of fresh-cut narrow-leaf cattail. This study laid the foundation for the production and application of chlorine dioxide solution and promotion of rapid development of nar- row-leaf cattail industry.展开更多
Fresh-cut cattail was extremely not resistant to store at room temperature.In the first day,it began to etiolate and rot,the fiber content increased,but the vitamin C content and reducing sugar content decreased.The a...Fresh-cut cattail was extremely not resistant to store at room temperature.In the first day,it began to etiolate and rot,the fiber content increased,but the vitamin C content and reducing sugar content decreased.The aerobic bacterial count increased,the weight loss rate sharply increased,and the sensory quality and food value were gradually lost.Low temperature storage could decrease the loss of vitamin C and reducing sugar of fresh-cut cattail,reduce the weight loss rate and delay the increase of fiber content,maintain the water and nutrient of fresh-cut cattail,and the storage effect of 0 ℃ was better than 4 ℃.展开更多
Here,we report the mechanical and water sorption properties of a green composite based on Typha latifolia fibres.The composite was prepared either completely binder-less or bonded with 10%(w/w)of a bio-based resin whi...Here,we report the mechanical and water sorption properties of a green composite based on Typha latifolia fibres.The composite was prepared either completely binder-less or bonded with 10%(w/w)of a bio-based resin which was a mixture of an epoxidized linseed oil and a tall-oil based polyamide.The flexural modulus of elasticity,the flexural strength and the water absorption of hot pressed Typha panels were measured and the influence of pressing time and panel density on these properties was investigated.The cure kinetics of the biobased resin was analyzed by differential scanning calorimetry(DSC)in combination with the iso-conversional kinetic analysis method of Vyazovkin to derive the curing conditions required for achieving completely cured resin.For the binderless Typha panels the best technological properties were achieved for panels with high density.By adding 10%of the binder resin the flexural strength and especially the water absorption were improved significantly.展开更多
A molecular biology method, fluorescent in situ hybridization(FISH), in which the pre-treatment was improved in allusion to the media of the constructed wetlands(CW), e.g. the soil and the grit, was used to invest...A molecular biology method, fluorescent in situ hybridization(FISH), in which the pre-treatment was improved in allusion to the media of the constructed wetlands(CW), e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria(AOB) quantity and the relation with oxidation-reduction potential(ORP) in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.展开更多
In this article, information about the geographical location of the Karakir Lake in Bukhara region, high water plants, systematics and their distribution is presented. As a result of the research, Lake Karakir has 34 ...In this article, information about the geographical location of the Karakir Lake in Bukhara region, high water plants, systematics and their distribution is presented. As a result of the research, Lake Karakir has 34 species of high water plants belonging to 16 families. These plants were divided into ecological groups and analyzed.展开更多
The concentrations of Ag, Co and Ni in the sediments and the different organs of Typha domingensis from Lake Burullus, Egypt, were investigated monthly from February to September 2010 to evaluate the aquatic environme...The concentrations of Ag, Co and Ni in the sediments and the different organs of Typha domingensis from Lake Burullus, Egypt, were investigated monthly from February to September 2010 to evaluate the aquatic environment quality of the lake and to test the suitability of these organs for bio-indicating of sediment metals. The sediment heavy metals were found to decrease in the order of Ni > Co > Ag. The sediment contents of Ag were about 45 times above the worldwide range. On the other hand, Co concentrations were below the reference ranges of United States and Chinese soils. The heavy metals bioaccumulation decreased according to the order of rhizome > root > leaf for Ag;and root > rhizome > leaf for Co and Ni. It was found also that, T. domingensis had no significant differences in heavy metals concentrations over time. The transfer factors of Ag, Co and Ni from sediment to below-ground organs were smaller than one. Co had the maximum transport from below-ground to above-ground organs, while Ag had the minimum. There was a significant linear correlation between the concentration of Ag in root of T. domingensis and that in sediment. This result suggested that T. domingensis can be regarded as bio-indicator for Ag pollution of Lake Burullus.展开更多
In this study,ecofriendly and economic carboxy-terminated plant fibers(PFs)were used as adsorbents for the effective in-syringe solid phase extraction(IS-SPE)of fluoroquinolone(FQ)residues from water.Based on the ther...In this study,ecofriendly and economic carboxy-terminated plant fibers(PFs)were used as adsorbents for the effective in-syringe solid phase extraction(IS-SPE)of fluoroquinolone(FQ)residues from water.Based on the thermal esterification and etherification reaction of cellulose hydroxy with citric acid(CA)and sodium chloroacetate in aqueous solutions,carboxy groups grafted onto cotton,cattail,and corncob fibers were fabricated.Compared with carboxy-terminated corncob and cotton,CA-modified cattail with more carboxy groups showed excellent adsorption capacity for FQs.The modified cattail fibers were reproducible and reusable with relative standard deviations of 3.2%-4.2% within 10 cycles of adsorptiondesorption.A good extraction efficiency of 71.3%-80.9% was achieved after optimizing the extraction condition.Based on carboxylated cattail,IS-SPE coupled with ultra-performance liquid chromatography with a photodiode array detector was conducted to analyze FQs in environmental water samples.High sensitivity with limit of detections of 0.08-0.25 mg/L and good accuracy with recoveries of 83.8%-111.7% were obtained.Overall,the simple and environment-friendly modified waste PFs have potential applications in the effective extraction and detection of FQs in natural waters.展开更多
Typha shuttleworthii is the semi-aquatic plant in the modern areal which embraces mainly the ocean districts of Europe. The eastern border of the area of this species is located in Eastern Europe on the territory of V...Typha shuttleworthii is the semi-aquatic plant in the modern areal which embraces mainly the ocean districts of Europe. The eastern border of the area of this species is located in Eastern Europe on the territory of Vyatka-Kama Cis-Urals (VKCU). Almost everywhere species is considered rare and is included in the Red Data Books in many European countries. However, on the territory of Russia, T. shuttleworthii is not protected. The rarity of this species makes it necessary to study its natural populations for their protection. In the paper, we present the materials on some biological and ecological features of the Typha shuttleworthii, growing on the territory of Vyatka-Kama Cis-Urals, where the species is represented by its extreme eastern populations. This species is offered to the protection on the territory of the European part of Russia within the Republic of Tatarstan and Udmurtia.展开更多
Cattail, a type of herbaceous emergent aquatic macrophyte, has upright-standing leaves with a large slenderness ratio and a ehiral morphology. With the aim of understanding the effect of chiral morphology on their mec...Cattail, a type of herbaceous emergent aquatic macrophyte, has upright-standing leaves with a large slenderness ratio and a ehiral morphology. With the aim of understanding the effect of chiral morphology on their mechanical behavior, we investi- gated, both experimentally and theoretically, the twisting chiral morphologies and wind-adaptive reconfigurations of cattail leaves. Their multiscale structures were observed by using optical microscope and scanning electron microscopy. Their me- chanical properties were measured by uniaxial tension and three-point bending tests. By modeling a chiral leaf as a pre-twisted cantilever-free beam, fluid dynamics simulations were performed to elucidate the synergistic effects of the leaf's chiral mor- phology and reconfiguration in wind. It was observed that the leaves have evolved multiscale structures and superior mechanical properties, both of which feature functionally gradient variations in the height direction, to improve their ability to resist lodging failure by reducing the maximal stress. The synergistic effect ofchiral morphology and reconfiguration can greatly improve the survivability of cattail plants in wind.展开更多
Introduction:Although fire as a critical ecological process shapes the Florida Everglades landscape,researchers lack landscape-based approach for fire management.The interactive effect of fire,nutrients,water depth,an...Introduction:Although fire as a critical ecological process shapes the Florida Everglades landscape,researchers lack landscape-based approach for fire management.The interactive effect of fire,nutrients,water depth,and invasive cattails(Typha spp.)on vegetation communities is of special concern for ecosystem restoration.In particular,questions concerning the effect of fire on nutrient release and,by extension,the potential thereof to stimulate sawgrass(Cladium jamaicense Crantz)re-growth and cattail expansion under varying hydrological conditions are of immediate relevance to ecologists and land managers who work to restore the Everglades.Methods:In late April of 1999,a 42,875 ha surface fire,including a 100 ha peat fire,burned the northern section of Water Conservation Area 3A(WCA-3A)in the Everglades.In this study,total phosphorus(TP)in soil,surface water,pore-water,and vegetation was sampled at non-burned,surface-burned and peat-burned areas within one and five months after the burn.Four years after the initial fire,field data were collected in a large scale survey to analyze how the 1999 fire affected cattail distribution in the altered landscape of high soil TP and cattail habitats.Existing GIS maps were utilized to select field sampling locations and to provide additional information for the analysis.Results:The analyses showed that five months after the fire,sawgrass biomass re-growth was about 5 times higher in burned areas(611±47 g/m^(2))than in non-burned areas(102±18 g/m^(2)).Sawgrass re-growth in water depths less than 30 cm was 4.9±0.4 g/m^(2)/day while sawgrass re-growth in water depths deeper than 60 cm decreased to 0.5±0.3 g/m^(2)/day.Cattail biomass re-growth in peat-burned areas was as high as 1,079±38 g/m^(2).The data also showed that post-fire cattail expansion could be related to cattail stands existing before the fire.Furthermore,post-fire cattail appeared more significant expansion in the areas with soil TP above 900 mg/kg than in that with soil TP below 900 mg/kg.Conclusions:The data showed that fire within altered landscapes(e.g.high soil TP and/or cattail)of the Everglades could stimulate the re-growth and expansion of cattails,and post-fire re-growth of sawgrass could be severely impeded by deep water after a surface-burn.This research indicates that fire continues to be an effective ecological process for maintaining the Everglades;therefore,ecologists and land managers may have to reevaluate the future management of natural fire with regard to its dynamic relationship with high soil TP and cattail expansion in the altered Everglades landscape.展开更多
Background:Florida’s Everglades is a vast freshwater peatland that has been impacted by the alterations of hydrological pattern and water quality which led to changes in plant species composition and biodiversity.In ...Background:Florida’s Everglades is a vast freshwater peatland that has been impacted by the alterations of hydrological pattern and water quality which led to changes in plant species composition and biodiversity.In this study,carbon and nitrogen stable isotopes(δ13C andδ15N)in cattail(Typha domingensis)are evaluated as indicators of environmental changes in the Everglades wetlands along nutrient and hydrological gradients represented by reference sites with total phosphorus(TP)<10μg L−1,transition sites with TP≥10μg L−1<20μg L−1 and impacted sites with TP≥20μg L−1 which differed in hydrology or habitats(marsh and canal).Results:Cattailδ13C values decreased significantly from reference(–24.1‰),transition(–26.8‰)to the impacted sites(–28.2‰).In contrast,δ15N values increased significantly from reference(–5.2‰),transition(2.4‰)to the impacted site(5.9‰).In response to a poor hydrological condition,cattail in marsh area displayed 13C enrichment(–26.0‰)and 15N depletion(0.2‰).By contrast,cattail grown in the canal sites with favorable hydropattern displayed 13C depletion(–27.6‰)and 15N enrichment(5.9‰)from the canal sites with more favorable hydrological condition.Conclusions:The different patterns for the changes inδ13C andδ15N in cattail suggested that increased nutrients led to increased stomatal conductance and 13C fractionation during carbon uptake and decreased 15N fractionation with increasing nitrogen demand while poor hydrological condition coupled with low nutrients led to reduced plant growth indicated by higherδ13C and lowerδ15N values.Findings from this study suggested thatδ13C in emerged macrophytes such as cattail can be used as an indicator for environmental stress whileδ15N is a robust indicator for wetland eutrophication.展开更多
基金supported by the National Key Technology R&D Program for the 11th Five-year Plan of China (No.2006BAC10B03)the National Natural Science Foundation of China-Japan Science and Technology Agency (NSFC-JST) Strategic Joint Research Project (No.50721140017)the National Natural Science Foundation of China (No.50508019)
文摘Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature 〉 activated time 〉 impregnation ratio 〉 impregnation time. The optimum condition was found at an impregnation ratio of 2.5, an impregnation time of 9 hr, an activated temperature of 500℃, and an activated time of 80 min. The Brunauer-Emmett-Teller surface area and average pore size of the activated carbon were 1279 m^2/g and 5.585 nm, respectively. A heterogeneous structure in terms of both size and shape was highly developed and widely distributed on the carbon surface. Some groups containing oxygen and phosphorus were formed, and the carboxyl group was the major oxygen-containing functional group. An isotherm equilibrium study was carried out to investigate the adsorption capacity of the activated carbon. The data fit the Langmuir isotherm equation, with maximum monolayer adsorption capacities of 192.30 mg/g for Neutral Red and 196.08 mg/g for Malachite Green. Dye-exhausted carbon could be regenerated effectively by thermal treatment. The results indicated that cattail-derived activated carbon was a promising adsorbent for the removal of cationic dyes from aqueous solutions.
基金Supported by Practice and Innovation Training Project for College Students in Jiangsu Province(2012JSSPITP3590)
文摘At present, chlorine dioxide has been widely used as a bactericide that may become an alternative to chlorine. In this study, fresh-cut narrow-leaf cattail was soaked with 45, 70 and 95 mg/L chlorine dioxide solution, respectively. Fresh-cut narrow-leaf cattail samples were collected regularly to determine changes in surface microbe amount, cellulose content, Vc content, reduction sugar content and sensory quality of narrow-leaf cattail, thus analyzing the effects of chlorine diox- ide on sterilization and preservation of fresh-cut narrow-leaf cattail. The results showed that all three concentrations of chlorine dioxide solution could significantly reduce the amount of microbes on the surface of fresh-cut narrow-leaf cattail and improve the edible safety of products. The initial sterilization efficiency was im- proved gradually as the concentration of chlorine dioxide increased. In addition, chlorine dioxide treatment postponed the increase of cellulose content of fresh-cut narrow-leaf cattail. However, chlorine dioxide oxidized Vc and reducing sugar, and its bleaching effect also exerted a certain impact on the sensory quality of fresh- cut narrow-leaf cattail. Based on comprehensive comparisons, 45 - 70 mg/L chlorine dioxide solution exerted the best effects on sterilization and preservation of fresh-cut narrow-leaf cattail. This study laid the foundation for the production and application of chlorine dioxide solution and promotion of rapid development of nar- row-leaf cattail industry.
基金Supported by Students Practice Innovation Projects in Jiangsu Province(2012JSSPITP3590)
文摘Fresh-cut cattail was extremely not resistant to store at room temperature.In the first day,it began to etiolate and rot,the fiber content increased,but the vitamin C content and reducing sugar content decreased.The aerobic bacterial count increased,the weight loss rate sharply increased,and the sensory quality and food value were gradually lost.Low temperature storage could decrease the loss of vitamin C and reducing sugar of fresh-cut cattail,reduce the weight loss rate and delay the increase of fiber content,maintain the water and nutrient of fresh-cut cattail,and the storage effect of 0 ℃ was better than 4 ℃.
基金funding and support from the Austrian Research Promotion Agency(FFG).
文摘Here,we report the mechanical and water sorption properties of a green composite based on Typha latifolia fibres.The composite was prepared either completely binder-less or bonded with 10%(w/w)of a bio-based resin which was a mixture of an epoxidized linseed oil and a tall-oil based polyamide.The flexural modulus of elasticity,the flexural strength and the water absorption of hot pressed Typha panels were measured and the influence of pressing time and panel density on these properties was investigated.The cure kinetics of the biobased resin was analyzed by differential scanning calorimetry(DSC)in combination with the iso-conversional kinetic analysis method of Vyazovkin to derive the curing conditions required for achieving completely cured resin.For the binderless Typha panels the best technological properties were achieved for panels with high density.By adding 10%of the binder resin the flexural strength and especially the water absorption were improved significantly.
文摘A molecular biology method, fluorescent in situ hybridization(FISH), in which the pre-treatment was improved in allusion to the media of the constructed wetlands(CW), e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria(AOB) quantity and the relation with oxidation-reduction potential(ORP) in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.
文摘In this article, information about the geographical location of the Karakir Lake in Bukhara region, high water plants, systematics and their distribution is presented. As a result of the research, Lake Karakir has 34 species of high water plants belonging to 16 families. These plants were divided into ecological groups and analyzed.
文摘The concentrations of Ag, Co and Ni in the sediments and the different organs of Typha domingensis from Lake Burullus, Egypt, were investigated monthly from February to September 2010 to evaluate the aquatic environment quality of the lake and to test the suitability of these organs for bio-indicating of sediment metals. The sediment heavy metals were found to decrease in the order of Ni > Co > Ag. The sediment contents of Ag were about 45 times above the worldwide range. On the other hand, Co concentrations were below the reference ranges of United States and Chinese soils. The heavy metals bioaccumulation decreased according to the order of rhizome > root > leaf for Ag;and root > rhizome > leaf for Co and Ni. It was found also that, T. domingensis had no significant differences in heavy metals concentrations over time. The transfer factors of Ag, Co and Ni from sediment to below-ground organs were smaller than one. Co had the maximum transport from below-ground to above-ground organs, while Ag had the minimum. There was a significant linear correlation between the concentration of Ag in root of T. domingensis and that in sediment. This result suggested that T. domingensis can be regarded as bio-indicator for Ag pollution of Lake Burullus.
基金supported by the National Natural Science Foundation of China(Grant Nos.:81703469 and 81973277)Open Fund of the State Key Laboratory of Quality Research in Chinese Medicine,University of Macao(Grant No.:SKL-QRCM(UM)-2020-2022,QRCM-OP21007)the World-Class Universities(Disciplines)and the Characteristic Development Guidance Funds for the Central Universities(Grant No.:PY3A012).
文摘In this study,ecofriendly and economic carboxy-terminated plant fibers(PFs)were used as adsorbents for the effective in-syringe solid phase extraction(IS-SPE)of fluoroquinolone(FQ)residues from water.Based on the thermal esterification and etherification reaction of cellulose hydroxy with citric acid(CA)and sodium chloroacetate in aqueous solutions,carboxy groups grafted onto cotton,cattail,and corncob fibers were fabricated.Compared with carboxy-terminated corncob and cotton,CA-modified cattail with more carboxy groups showed excellent adsorption capacity for FQs.The modified cattail fibers were reproducible and reusable with relative standard deviations of 3.2%-4.2% within 10 cycles of adsorptiondesorption.A good extraction efficiency of 71.3%-80.9% was achieved after optimizing the extraction condition.Based on carboxylated cattail,IS-SPE coupled with ultra-performance liquid chromatography with a photodiode array detector was conducted to analyze FQs in environmental water samples.High sensitivity with limit of detections of 0.08-0.25 mg/L and good accuracy with recoveries of 83.8%-111.7% were obtained.Overall,the simple and environment-friendly modified waste PFs have potential applications in the effective extraction and detection of FQs in natural waters.
文摘Typha shuttleworthii is the semi-aquatic plant in the modern areal which embraces mainly the ocean districts of Europe. The eastern border of the area of this species is located in Eastern Europe on the territory of Vyatka-Kama Cis-Urals (VKCU). Almost everywhere species is considered rare and is included in the Red Data Books in many European countries. However, on the territory of Russia, T. shuttleworthii is not protected. The rarity of this species makes it necessary to study its natural populations for their protection. In the paper, we present the materials on some biological and ecological features of the Typha shuttleworthii, growing on the territory of Vyatka-Kama Cis-Urals, where the species is represented by its extreme eastern populations. This species is offered to the protection on the territory of the European part of Russia within the Republic of Tatarstan and Udmurtia.
文摘Cattail, a type of herbaceous emergent aquatic macrophyte, has upright-standing leaves with a large slenderness ratio and a ehiral morphology. With the aim of understanding the effect of chiral morphology on their mechanical behavior, we investi- gated, both experimentally and theoretically, the twisting chiral morphologies and wind-adaptive reconfigurations of cattail leaves. Their multiscale structures were observed by using optical microscope and scanning electron microscopy. Their me- chanical properties were measured by uniaxial tension and three-point bending tests. By modeling a chiral leaf as a pre-twisted cantilever-free beam, fluid dynamics simulations were performed to elucidate the synergistic effects of the leaf's chiral mor- phology and reconfiguration in wind. It was observed that the leaves have evolved multiscale structures and superior mechanical properties, both of which feature functionally gradient variations in the height direction, to improve their ability to resist lodging failure by reducing the maximal stress. The synergistic effect ofchiral morphology and reconfiguration can greatly improve the survivability of cattail plants in wind.
文摘Introduction:Although fire as a critical ecological process shapes the Florida Everglades landscape,researchers lack landscape-based approach for fire management.The interactive effect of fire,nutrients,water depth,and invasive cattails(Typha spp.)on vegetation communities is of special concern for ecosystem restoration.In particular,questions concerning the effect of fire on nutrient release and,by extension,the potential thereof to stimulate sawgrass(Cladium jamaicense Crantz)re-growth and cattail expansion under varying hydrological conditions are of immediate relevance to ecologists and land managers who work to restore the Everglades.Methods:In late April of 1999,a 42,875 ha surface fire,including a 100 ha peat fire,burned the northern section of Water Conservation Area 3A(WCA-3A)in the Everglades.In this study,total phosphorus(TP)in soil,surface water,pore-water,and vegetation was sampled at non-burned,surface-burned and peat-burned areas within one and five months after the burn.Four years after the initial fire,field data were collected in a large scale survey to analyze how the 1999 fire affected cattail distribution in the altered landscape of high soil TP and cattail habitats.Existing GIS maps were utilized to select field sampling locations and to provide additional information for the analysis.Results:The analyses showed that five months after the fire,sawgrass biomass re-growth was about 5 times higher in burned areas(611±47 g/m^(2))than in non-burned areas(102±18 g/m^(2)).Sawgrass re-growth in water depths less than 30 cm was 4.9±0.4 g/m^(2)/day while sawgrass re-growth in water depths deeper than 60 cm decreased to 0.5±0.3 g/m^(2)/day.Cattail biomass re-growth in peat-burned areas was as high as 1,079±38 g/m^(2).The data also showed that post-fire cattail expansion could be related to cattail stands existing before the fire.Furthermore,post-fire cattail appeared more significant expansion in the areas with soil TP above 900 mg/kg than in that with soil TP below 900 mg/kg.Conclusions:The data showed that fire within altered landscapes(e.g.high soil TP and/or cattail)of the Everglades could stimulate the re-growth and expansion of cattails,and post-fire re-growth of sawgrass could be severely impeded by deep water after a surface-burn.This research indicates that fire continues to be an effective ecological process for maintaining the Everglades;therefore,ecologists and land managers may have to reevaluate the future management of natural fire with regard to its dynamic relationship with high soil TP and cattail expansion in the altered Everglades landscape.
基金from an Overseas Research collaboration grant(2018AHB020)funded by Hubei Province,China.
文摘Background:Florida’s Everglades is a vast freshwater peatland that has been impacted by the alterations of hydrological pattern and water quality which led to changes in plant species composition and biodiversity.In this study,carbon and nitrogen stable isotopes(δ13C andδ15N)in cattail(Typha domingensis)are evaluated as indicators of environmental changes in the Everglades wetlands along nutrient and hydrological gradients represented by reference sites with total phosphorus(TP)<10μg L−1,transition sites with TP≥10μg L−1<20μg L−1 and impacted sites with TP≥20μg L−1 which differed in hydrology or habitats(marsh and canal).Results:Cattailδ13C values decreased significantly from reference(–24.1‰),transition(–26.8‰)to the impacted sites(–28.2‰).In contrast,δ15N values increased significantly from reference(–5.2‰),transition(2.4‰)to the impacted site(5.9‰).In response to a poor hydrological condition,cattail in marsh area displayed 13C enrichment(–26.0‰)and 15N depletion(0.2‰).By contrast,cattail grown in the canal sites with favorable hydropattern displayed 13C depletion(–27.6‰)and 15N enrichment(5.9‰)from the canal sites with more favorable hydrological condition.Conclusions:The different patterns for the changes inδ13C andδ15N in cattail suggested that increased nutrients led to increased stomatal conductance and 13C fractionation during carbon uptake and decreased 15N fractionation with increasing nitrogen demand while poor hydrological condition coupled with low nutrients led to reduced plant growth indicated by higherδ13C and lowerδ15N values.Findings from this study suggested thatδ13C in emerged macrophytes such as cattail can be used as an indicator for environmental stress whileδ15N is a robust indicator for wetland eutrophication.