Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian z...Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m?00 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200-1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection.展开更多
Based on the time series data from the Aral hydrological station for the period of 1958-2005,the paper re-veals the long-term trend and fractal of the annual runoff process in the mainstream of the Tarim River by usin...Based on the time series data from the Aral hydrological station for the period of 1958-2005,the paper re-veals the long-term trend and fractal of the annual runoff process in the mainstream of the Tarim River by using the wavelet analysis method and the fractal theory.The main conclusions are as follows:1)From a large time scale point of view,i.e.the time scale of 16(24)years,the annual runoff basically shows a slightly decreasing trend as a whole from 1958 to 2005.If the time scale is reduced to 8(23)or 4(22)years,the annual runoff still displays the basic trend as the large time scale,but it has fluctuated more obviously during the period.2)The correlation dimension for the annual runoff process is 3.4307,non-integral,which indicates that the process has both fractal and chaotic characteris-tics.The correlation dimension is above 3,which means that at least four independent variables are needed to describe the dynamics of the annual runoff process.3)The Hurst exponent for the first period(1958-1973)is 0.5036,which equals 0.5 approximately and indicates that the annual runoff process is in chaos.The Hurst exponents for the second(1974-1989)and third(1990-2005)periods are both greater than 0.50,which indicate that the annual runoff process showed a long-enduring characteristic in the two periods.The Hurst exponent for the period from 1990 to 2005 indi-cates that the annual runoff will show a slightly increasing trend in the 16 years after 2005.展开更多
From April 2008 to November 2009, the nitrogen （N） cycle of plant-soil system in seepweed （Suaeda salsa） wetland in the intertidal zone of the Huanghe （Yellow） River estuary was studied. Results showed that soil...From April 2008 to November 2009, the nitrogen （N） cycle of plant-soil system in seepweed （Suaeda salsa） wetland in the intertidal zone of the Huanghe （Yellow） River estuary was studied. Results showed that soil N had sig- nificant seasonal fluctuations and vertical distribution, and the net N mineralization rates in topsoil were significantly different in growing season （p 〈 0.01）. The N/P ratio （9.87 ±1.23） of S. salsa was less than 14, indicating that plant growth was limited by N. The N accumulated in S. salsa litter at all times during decomposition, which was ascribed to the N immobilization by microbes from the environment. Soil organic N was the main N stock of plant-soil system, accounting for 97.35% of the total N stock. The N absorption and utilization coefficients of S. salsa were very low （0.0145 and 0.3844, respectively）, while the N cycle coefficient was high （0.7108）. The results of the N turnovers among compartments of S. salsa wetland showed that the N uptake amount of aboveground part and root were 7.764 g/m2and 4.332 g/m2, respectively. The N translocation amounts from aboveground part to root and from root to soil were 3.881 g/m2 and 0.626 g/m2, respectively. The N translocation amount from aboveground living body to litter was 3.883 g/m2, the annual N return amount from litter to soil was more than 0.125（-） g/m2 （minus represented immobili- zation）, and the net N mineralization amount in topsoil （0-15 cm） in growing season was 1.190 g/m2. The assessment of N biological cycle status orS. salsa wetland indicated that N was a very important limiting factor and the ecosystem was situated in unstable and vulnerable status. The S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the N quantitative relationships determined in the compartment model might provide scientific base for us to reveal the special adaptive strategy orS. salsa to the vulnerable habitat in the following studies.展开更多
Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average conce...Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average concentration of DIN increased and the PO4-P concentration sharply decreased compared to the previous data of corresponding period. The high concentrations of DIN and PO4-P occurred in coastal waters, especially in the bays and some river estuaries, while the high concentrations of SiO3-Si in the surface and middle depth occurred in the central area of the Bohai Sea. The average ratio of DIN/PO4-P was much higher than the Redfield Ratio （16：1）. Apparently, PO4-P was one of the limiting nutrient for phytoplankton growing in the sea. The average concentrations of DON and DOP were higher than their inorganic forms. The results of eutrophication assessment show that 22.1% of all stations were classified as violating the concentration levels of the National Seawater Quality Standard （GB 3097-1997） for DIN and only 3.9% for PO4-R The average eutrophication index in the overall area was 0.21±0.22 and the high values occurred in Bohai Bay, Liaodong Bay and near the Yellow River estuary. This means that the state of eutrophication was generally mesotrophic in the Bohai Sea, but relatively worse in the bays, especially some river estuaries.展开更多
Current vegetation patterns, biodiversity and adaptation of plants were studied during 1998-2001 in glacial landscape of Chaurabari situated above Kedarnath （30° 44＇ N- 79° 07＇ E; 3,000- 6,000 m） in Cent...Current vegetation patterns, biodiversity and adaptation of plants were studied during 1998-2001 in glacial landscape of Chaurabari situated above Kedarnath （30° 44＇ N- 79° 07＇ E; 3,000- 6,000 m） in Central Himalaya. Landscape was identified into different zones on account of the vegetation status, glacial features, geomorphology and altitudes. Cold environment with heavy snowfall, frost hailstorm and dense frost characterizes the study area Predominance of the soda rich feldspars indicates soda enrichment; orthoclase, microcline weathering and alternation would have contributed potash to the soil. The increasing severity of the environment as we ascend from timberline to snowline leads to progressive decline in the abundance and diversity of the plant species. The diversity of the higher plants decrease, while the diversity of microflora increase from alpine zone to snowline zone. Highly opulent and diverse flora with beautiful, delicate herbs occupy the alpine zone, but some specialized groups of the plants, particularly high energetic and cold resistant species reside in glacial environment. Asteraceae, Rananculaceae, Primulaceae, Rosaceae, Apiaceae and Ericaceae are the pioneer angiospermic families, while Anaphalis triplinervis, A. royleana, Androsacce sarmentosa, Cotoneaster rotundifolius,Lonicera myrtillus, Cassiope fastigiata, Gaultheria trichophylla and Erigeron multiradiatus are the pioneer species, which have invaded in glacial environment. Through its nature, alpine glacial ecotone can be seen easily due to environmental and edaphic differences.展开更多
A total of 348 species belonging to 8 phyla and 125 genera were observed in seasonally sampled phytoplankton of tidal rivers from 13 sampling sites around Luoyuan Bay, and all field samplings were carried out in produ...A total of 348 species belonging to 8 phyla and 125 genera were observed in seasonally sampled phytoplankton of tidal rivers from 13 sampling sites around Luoyuan Bay, and all field samplings were carried out in productive period(March/June/August/December) at ebb tide. Bacillariophyta species were the most abundant species, followed by Chlorophyta, Cyanophytes, Euglenophyta, Cryptophyta, Dinophyta, Xanthophyta and Chrysophytas. Seasonal distribution index(SDI) value ranged from 0.63 to 0.86, which meant that species found at those sites in 4 seasons tended to be largely different. Phytoplankton individuals ranged from 5.939×10~4 ind L^(-1) in winter to 75.31×10~4 ind L^(-1) in autumn. Phytoplankton biomass ranged from 0.620 mg L^(-1) in summer to 2.373 mg L^(-1) in autumn. The grey correlation analysis(GCA) showed that the nutrient variables played an important role in the influence on phytoplankton community in every season. The canonical correspondence analysis(CCA) revealed impact of environmental variables on the different species, most of Bacillariophyta species were negative correlation with nutrients(TP and NH_3-N) in the four seasons, Chlorophyta species and Cyanophyta species did not show obvious correlation with environment variables in every season. The combination of GRA analysis and CCA analysis provided a method to quantitatively reveal the correlation between phytoplankton community and environmental variables in water body of tidal rivers at this region.展开更多
A brief information about two subspecies mollusks in the bank of Amu Darya river is collected according to the experience. As a result, we identified 9 types and 2 small types of two sub species mollusks live in Amu D...A brief information about two subspecies mollusks in the bank of Amu Darya river is collected according to the experience. As a result, we identified 9 types and 2 small types of two sub species mollusks live in Amu Darya river. Sinanodonta gibba, Sinanodonta orbicularis and Sinanodonta puerorum types for fauna were shown for the first time from the river.展开更多
Mercury concentration in water, sediments and two aquatic plants were measured in the Tigris River for the period in 2013 Hg concentrations in water between 0.18-0.74 μg/g, however, in sediments ranged between 0.66-0...Mercury concentration in water, sediments and two aquatic plants were measured in the Tigris River for the period in 2013 Hg concentrations in water between 0.18-0.74 μg/g, however, in sediments ranged between 0.66-0.73 lag/g. The concentrations of accumulated mercury in aquatic plants ranged in Ceratophyllum demersum and Phragmitus australis were 0.035-0.022, 0.028-0.023 μg/g, respectively. The concentration bioconcentration factor B.C.F range between 0.331-0.209 μg/g and B.S.F 0.043-0.011 μg/g. These results indicate the ability of the aquatic plants of Tigris River to accumulate elements in their tissues more than water consequently, mercury concentrations in the food chain path way could cause health problems on public health by transfer through aquatic organisms to human. The studied plants could be considered as bioindicator for elements flow to the river from natural and anthropogenic sources. The study showed there is an increase in the concentration of this element in the Tigris River and due to the low rate of discharge of river water, which leads to high concentrations of ions dissolved and effect divorced industrial waste and sewage and irrigation water, especially in the area of Zafaraniyah a result of the large number of events industrialized as well as the impact of the Diyala River on the River Tigris.展开更多
Danube Delta--a unique, young and continuing growing region, is a favorable place for developing a unique flora and fauna with many rare and protected species in Europe. Even though the terrestrial environment is pres...Danube Delta--a unique, young and continuing growing region, is a favorable place for developing a unique flora and fauna with many rare and protected species in Europe. Even though the terrestrial environment is present in the area, the predominance of the aquatic environment led to the existence of a particular macrophytic flora. At the contact point of the sea-water and freshwater, physical, chemical and biological processes occur. As a consequence, researchers consider these coastal waters special ecosystem, in which Musura bay is the most representative one. The purpose of this paper is to contribute to the study of aquatic submerged and floating macrophytes. The present study took place over two years （2013-2014）. In each year, a number of expeditions were made in different seasons in order to observe the diverse flora and flora associations. This due to seasonal variation in water quality, and might be a significantly seasonality of the vegetation also. The importance of the studies regarding flora of the Danube Delta, consist in the fact that the plants in this area are of social and economical importance, but also very important for environmental conservation.展开更多
Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the ups...Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the upstream sections of the River Cauvery are still intact, as they are located in sacred groves. To understand the dynamism of riparian forests exposed to anthropogenic pressures, the upstream stretch of Cauvery extending from Kushalanagara to Talacauvery （~102 km） was categorized into two landscapes： agro ecosystem and sacred （i.e. preserved）. The tree species were sampled using belt transects at 5 km intervals and the regeneration status of endemic species assessed using quadrats. A total of 128 species belonging to 47 families, and representing 1,590 individuals, was observed. Amongst them, 65% of unique species were exclusive to sacred landscapes. A rarefaction plot confirmed higher species richness for the sacred compared to the agro ecosystem landscapes, and diversity indices with more evenness in distribution were evident in sacred landscapes. A significant loss of endemic tree species in the agro ecosystem landscapes was found. Overall, this study demonstrates that an intense biotic pressure in terms of plantations and other anthropogenic activities have altered the species composition of the riparian zone in non-sacred areas. A permanent policy implication is required for the conservation of riparian buffers to avoid further ecosystem degradation and loss of biodiversity.展开更多
Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods ...Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods In this study,we conducted laboratory experiments to investigate the processes of DOM leaching from three common marsh plants(Phragmites australis,Suaeda salsa and Aeluropus littoralis)collected from the Yellow River Delta(YRD)salt marsh in October 2016.The YRD is one of the largest and most well-protected coastal ecosystems on the east coast of China.Important Findings We found that the plant leaves released DOM at much higher concentrations than the plant roots or stems,as measured by the dissolved organic carbon(DOC)and dissolved nitrogen(DN).On average,15%of the biomass C and 30%of the biomass N were released from the plant leaves as DOC and DN during the 27-day incubation period.The DOM released from the plants was very labile,and 92.4%-98.1%of the DOC and 88.0%-94.6%of the DN released from the plants were consumed by bacteria during the 27-day incubation period.The fluorescence characteristics of the plant-released DOM indicated that chromophoric dissolved organic matter was a major fraction of the DOM and that protein-like components were the primary organic fractions released from the plants.Bacterial degradation altered both the fluorescence properties and the chemical composition of the DOM.The results of the laboratory experiments were well supported by the field investigation,which indicated that a large amount of DOM was outwelled from the YRD salt marshes in late autumn.Our study suggests that the DOM released from the biomass of salt marsh plants provides an important source of both DOC and DN for marsh and coastal waters.The highly labile DOC and DN provide essential food sources to support microbial communities in the YRD salt marsh and adjacent coastal waters.展开更多
Recently, environmental pressures along coasts have increased substantially. Classification of estuaries according to their sus- ceptibility to eutrophication nutrient load is a useful method to determine priority man...Recently, environmental pressures along coasts have increased substantially. Classification of estuaries according to their sus- ceptibility to eutrophication nutrient load is a useful method to determine priority management objects and to enforce control measures. Using historical monitoring data from 2007 to 2012, from 65 estuaries, including 101 estuarine monitoring sections and 260 coastal monitoring stations, a nutrient-driven phytoplankton dynamic model was developed based on the relationship among phytoplankton biomass, Total Nitrogen （TN） load and physical features of estuaries. The ecological filter effect of es- tuaries was quantified by introducing conversion efficiency parameter values into the model. Markov Chain Monte Carlo algo- rithm of Bayesian inference was then employed to estimate parameters in the mode/. The developed model fitted well to the observed chlorophyll, primary production, grazing, and sinking rates. The analysis suggests that an estuary with Q/V （the ratio of river flow to estuarine volume） greater than 2.0 per year and e （conversion efficiency ratio） less than 1.0 g C/g N can be classified as less susceptible to TN load, Q/V between 0.7 to 2.0 per year and e between 1.0 to 3.0 g C/g N as moderately sus- ceptible, and e greater than 3.0 g C/g N as very susceptible. The estuaries with Q/V less than 0.7 per year vary greatly in their susceptibility. The estuaries with high and moderate susceptibility accounted for 67% of all the analyzed estuaries. They have relatively high eutrophication risks and should be the focus of environmental supervision and pollution prevention.展开更多
Wetlands are important for maintaining global ecosystem functions,mitigating global climate change,and regulating regional climate change.Ecological problems caused by global climate change have had serious impacts on...Wetlands are important for maintaining global ecosystem functions,mitigating global climate change,and regulating regional climate change.Ecological problems caused by global climate change have had serious impacts on plant distribution patterns in the wetlands of riparian zones,as well as on microbial community habitats in the soil.This study was based on a field sampling survey of the distribution characteristics of plant communities in the Ulson River,combined with remote sensing to obtain the spatial distribution pattern of vegetation in the riparian wetland.High-throughput sequencing technology combined with the characteristics of soil physicochemical factors were then used to explore the distribution characteristics of the community structures of soil bacteria and fungi under different vegetation types in the Ulson River Basin,in order to reveal the pattern of changes of soil microbial microorganisms under the different vegetation types in the wetlands of the riparian area and the factors driving those changes.The results showed an obvious banding phenomenon of wetland vegetation in the Ulson River Basin.Proteobacteria ranked first in relative abundance in all the sample plots and were the dominant bacteria in the study area.Ascomycota and Basidiomycota were the dominant fungi in the study area.In swamp areas,degenerate swamp soils,soil moisture content,and soil bulk density affected the microbial richness directly or indirectly by controlling soil nutrients.Plant aboveground biomass was the most significant factor influencing microbial diversity in a typical wet meadow sample.In salinized meadows and swamped meadows,electrical conductivity affected microbial richness and soil bulk density was the main factor influencing microbial diversity.The findings of this study can provide a theoretical basis for the ecological restoration of degraded riparian wetlands and further clarification of soil ecosystem functions in riparian wetlands.展开更多
基金This project was supported by National Natural Science Foundation of China (NSFC39970123) Changbai Mountain Open Research Station, Chinese Acedamy of Science.
文摘Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m?00 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200-1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection.
基金Under the auspices of the Second-stage Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-XB2-03)Major Direction of Knowledge Innovation Progromt of Chinese Academy of Sciences (No. KZCX2-YW-127)Shanghai Academic Discipline Project (Human Geography) (No. B410)
文摘Based on the time series data from the Aral hydrological station for the period of 1958-2005,the paper re-veals the long-term trend and fractal of the annual runoff process in the mainstream of the Tarim River by using the wavelet analysis method and the fractal theory.The main conclusions are as follows:1)From a large time scale point of view,i.e.the time scale of 16(24)years,the annual runoff basically shows a slightly decreasing trend as a whole from 1958 to 2005.If the time scale is reduced to 8(23)or 4(22)years,the annual runoff still displays the basic trend as the large time scale,but it has fluctuated more obviously during the period.2)The correlation dimension for the annual runoff process is 3.4307,non-integral,which indicates that the process has both fractal and chaotic characteris-tics.The correlation dimension is above 3,which means that at least four independent variables are needed to describe the dynamics of the annual runoff process.3)The Hurst exponent for the first period(1958-1973)is 0.5036,which equals 0.5 approximately and indicates that the annual runoff process is in chaos.The Hurst exponents for the second(1974-1989)and third(1990-2005)periods are both greater than 0.50,which indicate that the annual runoff process showed a long-enduring characteristic in the two periods.The Hurst exponent for the period from 1990 to 2005 indi-cates that the annual runoff will show a slightly increasing trend in the 16 years after 2005.
基金Under the auspices of Open Research Fund Program of Shandong Key Laboratory for Yellow River Delta Eco-Environmental Science,Binzhou,China (No.2007KFJJ01)Knowledge Innovation Programs of Chinese Academy of Sciences (No.KZCX2-YW-223)+1 种基金National Natural Science Foundation of China (No.40803023,41171424)Key Program of Natural Science Foundation of Shandong Province (No.ZR2010DZ001)
文摘From April 2008 to November 2009, the nitrogen （N） cycle of plant-soil system in seepweed （Suaeda salsa） wetland in the intertidal zone of the Huanghe （Yellow） River estuary was studied. Results showed that soil N had sig- nificant seasonal fluctuations and vertical distribution, and the net N mineralization rates in topsoil were significantly different in growing season （p 〈 0.01）. The N/P ratio （9.87 ±1.23） of S. salsa was less than 14, indicating that plant growth was limited by N. The N accumulated in S. salsa litter at all times during decomposition, which was ascribed to the N immobilization by microbes from the environment. Soil organic N was the main N stock of plant-soil system, accounting for 97.35% of the total N stock. The N absorption and utilization coefficients of S. salsa were very low （0.0145 and 0.3844, respectively）, while the N cycle coefficient was high （0.7108）. The results of the N turnovers among compartments of S. salsa wetland showed that the N uptake amount of aboveground part and root were 7.764 g/m2and 4.332 g/m2, respectively. The N translocation amounts from aboveground part to root and from root to soil were 3.881 g/m2 and 0.626 g/m2, respectively. The N translocation amount from aboveground living body to litter was 3.883 g/m2, the annual N return amount from litter to soil was more than 0.125（-） g/m2 （minus represented immobili- zation）, and the net N mineralization amount in topsoil （0-15 cm） in growing season was 1.190 g/m2. The assessment of N biological cycle status orS. salsa wetland indicated that N was a very important limiting factor and the ecosystem was situated in unstable and vulnerable status. The S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the N quantitative relationships determined in the compartment model might provide scientific base for us to reveal the special adaptive strategy orS. salsa to the vulnerable habitat in the following studies.
基金Supported by the National Natural Science Foundation of China (No. 40136020)Key International Technology Cooperation Plan (No. 2004DFA03600)the National Basic Research Program of China (973 Program, No. 2005CB422305)
文摘Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average concentration of DIN increased and the PO4-P concentration sharply decreased compared to the previous data of corresponding period. The high concentrations of DIN and PO4-P occurred in coastal waters, especially in the bays and some river estuaries, while the high concentrations of SiO3-Si in the surface and middle depth occurred in the central area of the Bohai Sea. The average ratio of DIN/PO4-P was much higher than the Redfield Ratio （16：1）. Apparently, PO4-P was one of the limiting nutrient for phytoplankton growing in the sea. The average concentrations of DON and DOP were higher than their inorganic forms. The results of eutrophication assessment show that 22.1% of all stations were classified as violating the concentration levels of the National Seawater Quality Standard （GB 3097-1997） for DIN and only 3.9% for PO4-R The average eutrophication index in the overall area was 0.21±0.22 and the high values occurred in Bohai Bay, Liaodong Bay and near the Yellow River estuary. This means that the state of eutrophication was generally mesotrophic in the Bohai Sea, but relatively worse in the bays, especially some river estuaries.
文摘Current vegetation patterns, biodiversity and adaptation of plants were studied during 1998-2001 in glacial landscape of Chaurabari situated above Kedarnath （30° 44＇ N- 79° 07＇ E; 3,000- 6,000 m） in Central Himalaya. Landscape was identified into different zones on account of the vegetation status, glacial features, geomorphology and altitudes. Cold environment with heavy snowfall, frost hailstorm and dense frost characterizes the study area Predominance of the soda rich feldspars indicates soda enrichment; orthoclase, microcline weathering and alternation would have contributed potash to the soil. The increasing severity of the environment as we ascend from timberline to snowline leads to progressive decline in the abundance and diversity of the plant species. The diversity of the higher plants decrease, while the diversity of microflora increase from alpine zone to snowline zone. Highly opulent and diverse flora with beautiful, delicate herbs occupy the alpine zone, but some specialized groups of the plants, particularly high energetic and cold resistant species reside in glacial environment. Asteraceae, Rananculaceae, Primulaceae, Rosaceae, Apiaceae and Ericaceae are the pioneer angiospermic families, while Anaphalis triplinervis, A. royleana, Androsacce sarmentosa, Cotoneaster rotundifolius,Lonicera myrtillus, Cassiope fastigiata, Gaultheria trichophylla and Erigeron multiradiatus are the pioneer species, which have invaded in glacial environment. Through its nature, alpine glacial ecotone can be seen easily due to environmental and edaphic differences.
基金financially supported by China Shenhua Energy Company Limited
文摘A total of 348 species belonging to 8 phyla and 125 genera were observed in seasonally sampled phytoplankton of tidal rivers from 13 sampling sites around Luoyuan Bay, and all field samplings were carried out in productive period(March/June/August/December) at ebb tide. Bacillariophyta species were the most abundant species, followed by Chlorophyta, Cyanophytes, Euglenophyta, Cryptophyta, Dinophyta, Xanthophyta and Chrysophytas. Seasonal distribution index(SDI) value ranged from 0.63 to 0.86, which meant that species found at those sites in 4 seasons tended to be largely different. Phytoplankton individuals ranged from 5.939×10~4 ind L^(-1) in winter to 75.31×10~4 ind L^(-1) in autumn. Phytoplankton biomass ranged from 0.620 mg L^(-1) in summer to 2.373 mg L^(-1) in autumn. The grey correlation analysis(GCA) showed that the nutrient variables played an important role in the influence on phytoplankton community in every season. The canonical correspondence analysis(CCA) revealed impact of environmental variables on the different species, most of Bacillariophyta species were negative correlation with nutrients(TP and NH_3-N) in the four seasons, Chlorophyta species and Cyanophyta species did not show obvious correlation with environment variables in every season. The combination of GRA analysis and CCA analysis provided a method to quantitatively reveal the correlation between phytoplankton community and environmental variables in water body of tidal rivers at this region.
文摘A brief information about two subspecies mollusks in the bank of Amu Darya river is collected according to the experience. As a result, we identified 9 types and 2 small types of two sub species mollusks live in Amu Darya river. Sinanodonta gibba, Sinanodonta orbicularis and Sinanodonta puerorum types for fauna were shown for the first time from the river.
文摘Mercury concentration in water, sediments and two aquatic plants were measured in the Tigris River for the period in 2013 Hg concentrations in water between 0.18-0.74 μg/g, however, in sediments ranged between 0.66-0.73 lag/g. The concentrations of accumulated mercury in aquatic plants ranged in Ceratophyllum demersum and Phragmitus australis were 0.035-0.022, 0.028-0.023 μg/g, respectively. The concentration bioconcentration factor B.C.F range between 0.331-0.209 μg/g and B.S.F 0.043-0.011 μg/g. These results indicate the ability of the aquatic plants of Tigris River to accumulate elements in their tissues more than water consequently, mercury concentrations in the food chain path way could cause health problems on public health by transfer through aquatic organisms to human. The studied plants could be considered as bioindicator for elements flow to the river from natural and anthropogenic sources. The study showed there is an increase in the concentration of this element in the Tigris River and due to the low rate of discharge of river water, which leads to high concentrations of ions dissolved and effect divorced industrial waste and sewage and irrigation water, especially in the area of Zafaraniyah a result of the large number of events industrialized as well as the impact of the Diyala River on the River Tigris.
文摘Danube Delta--a unique, young and continuing growing region, is a favorable place for developing a unique flora and fauna with many rare and protected species in Europe. Even though the terrestrial environment is present in the area, the predominance of the aquatic environment led to the existence of a particular macrophytic flora. At the contact point of the sea-water and freshwater, physical, chemical and biological processes occur. As a consequence, researchers consider these coastal waters special ecosystem, in which Musura bay is the most representative one. The purpose of this paper is to contribute to the study of aquatic submerged and floating macrophytes. The present study took place over two years （2013-2014）. In each year, a number of expeditions were made in different seasons in order to observe the diverse flora and flora associations. This due to seasonal variation in water quality, and might be a significantly seasonality of the vegetation also. The importance of the studies regarding flora of the Danube Delta, consist in the fact that the plants in this area are of social and economical importance, but also very important for environmental conservation.
文摘Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the upstream sections of the River Cauvery are still intact, as they are located in sacred groves. To understand the dynamism of riparian forests exposed to anthropogenic pressures, the upstream stretch of Cauvery extending from Kushalanagara to Talacauvery （~102 km） was categorized into two landscapes： agro ecosystem and sacred （i.e. preserved）. The tree species were sampled using belt transects at 5 km intervals and the regeneration status of endemic species assessed using quadrats. A total of 128 species belonging to 47 families, and representing 1,590 individuals, was observed. Amongst them, 65% of unique species were exclusive to sacred landscapes. A rarefaction plot confirmed higher species richness for the sacred compared to the agro ecosystem landscapes, and diversity indices with more evenness in distribution were evident in sacred landscapes. A significant loss of endemic tree species in the agro ecosystem landscapes was found. Overall, this study demonstrates that an intense biotic pressure in terms of plantations and other anthropogenic activities have altered the species composition of the riparian zone in non-sacred areas. A permanent policy implication is required for the conservation of riparian buffers to avoid further ecosystem degradation and loss of biodiversity.
基金supported by the National Natural Science Foundation of China(grants#41776082 and 41476057)Funds of Jiangsu Key Laboratory of Marine Biotechnology of Jiangsu Ocean University(HS2019005)the Funds of Jiangsu Key Laboratory of Marine Bioresources and Environment(SH20191205)and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods In this study,we conducted laboratory experiments to investigate the processes of DOM leaching from three common marsh plants(Phragmites australis,Suaeda salsa and Aeluropus littoralis)collected from the Yellow River Delta(YRD)salt marsh in October 2016.The YRD is one of the largest and most well-protected coastal ecosystems on the east coast of China.Important Findings We found that the plant leaves released DOM at much higher concentrations than the plant roots or stems,as measured by the dissolved organic carbon(DOC)and dissolved nitrogen(DN).On average,15%of the biomass C and 30%of the biomass N were released from the plant leaves as DOC and DN during the 27-day incubation period.The DOM released from the plants was very labile,and 92.4%-98.1%of the DOC and 88.0%-94.6%of the DN released from the plants were consumed by bacteria during the 27-day incubation period.The fluorescence characteristics of the plant-released DOM indicated that chromophoric dissolved organic matter was a major fraction of the DOM and that protein-like components were the primary organic fractions released from the plants.Bacterial degradation altered both the fluorescence properties and the chemical composition of the DOM.The results of the laboratory experiments were well supported by the field investigation,which indicated that a large amount of DOM was outwelled from the YRD salt marshes in late autumn.Our study suggests that the DOM released from the biomass of salt marsh plants provides an important source of both DOC and DN for marsh and coastal waters.The highly labile DOC and DN provide essential food sources to support microbial communities in the YRD salt marsh and adjacent coastal waters.
基金supported by Environmental Protection Public Welfare Project of China(Grant No.201309008)
文摘Recently, environmental pressures along coasts have increased substantially. Classification of estuaries according to their sus- ceptibility to eutrophication nutrient load is a useful method to determine priority management objects and to enforce control measures. Using historical monitoring data from 2007 to 2012, from 65 estuaries, including 101 estuarine monitoring sections and 260 coastal monitoring stations, a nutrient-driven phytoplankton dynamic model was developed based on the relationship among phytoplankton biomass, Total Nitrogen （TN） load and physical features of estuaries. The ecological filter effect of es- tuaries was quantified by introducing conversion efficiency parameter values into the model. Markov Chain Monte Carlo algo- rithm of Bayesian inference was then employed to estimate parameters in the mode/. The developed model fitted well to the observed chlorophyll, primary production, grazing, and sinking rates. The analysis suggests that an estuary with Q/V （the ratio of river flow to estuarine volume） greater than 2.0 per year and e （conversion efficiency ratio） less than 1.0 g C/g N can be classified as less susceptible to TN load, Q/V between 0.7 to 2.0 per year and e between 1.0 to 3.0 g C/g N as moderately sus- ceptible, and e greater than 3.0 g C/g N as very susceptible. The estuaries with Q/V less than 0.7 per year vary greatly in their susceptibility. The estuaries with high and moderate susceptibility accounted for 67% of all the analyzed estuaries. They have relatively high eutrophication risks and should be the focus of environmental supervision and pollution prevention.
基金The National Natural Science Foundation of China(32161143025,32160279,31960249)The Science and Technology Major Project of Inner Mongolia(2022YFHH0017,2021ZD0011)+1 种基金The Ordos Science and Technology Plan(2022EEDSKJZDZX010,2022EEDSKJXM005)The Mongolian Foundation for Science and Technology(NSFC_2022/01,CHN2022/276)。
文摘Wetlands are important for maintaining global ecosystem functions,mitigating global climate change,and regulating regional climate change.Ecological problems caused by global climate change have had serious impacts on plant distribution patterns in the wetlands of riparian zones,as well as on microbial community habitats in the soil.This study was based on a field sampling survey of the distribution characteristics of plant communities in the Ulson River,combined with remote sensing to obtain the spatial distribution pattern of vegetation in the riparian wetland.High-throughput sequencing technology combined with the characteristics of soil physicochemical factors were then used to explore the distribution characteristics of the community structures of soil bacteria and fungi under different vegetation types in the Ulson River Basin,in order to reveal the pattern of changes of soil microbial microorganisms under the different vegetation types in the wetlands of the riparian area and the factors driving those changes.The results showed an obvious banding phenomenon of wetland vegetation in the Ulson River Basin.Proteobacteria ranked first in relative abundance in all the sample plots and were the dominant bacteria in the study area.Ascomycota and Basidiomycota were the dominant fungi in the study area.In swamp areas,degenerate swamp soils,soil moisture content,and soil bulk density affected the microbial richness directly or indirectly by controlling soil nutrients.Plant aboveground biomass was the most significant factor influencing microbial diversity in a typical wet meadow sample.In salinized meadows and swamped meadows,electrical conductivity affected microbial richness and soil bulk density was the main factor influencing microbial diversity.The findings of this study can provide a theoretical basis for the ecological restoration of degraded riparian wetlands and further clarification of soil ecosystem functions in riparian wetlands.
