Glyphosate (GPS) is a non-selective, post-mergence herbicide that is widely used throughout the world. Due to the similar molecular structures of glyphosate and phosphate, adsorption of glyphosate on soil is easily af...Glyphosate (GPS) is a non-selective, post-mergence herbicide that is widely used throughout the world. Due to the similar molecular structures of glyphosate and phosphate, adsorption of glyphosate on soil is easily affected by coexisting phosphate, especially when phosphate is applied at a significant rate in farmland. This paper studied the effects of phosphate on the adsorption of glyphosate on three different types of Chinese soils including two variable charge soils and one permanent charge soil. The results indicated that Freundlich equations used to simulate glyphosate adsorption isotherms gave high correlation coefficients(0.990—0.998) with K values of 2751, 2451 and 166 for the zhuanhong soil(ZH soil, Laterite), red soil(RS, Udic Ferrisol) and Wushan paddy soil(WS soil, Anthrosol), respectively. The more the soil iron and aluminum oxides and clay contained, the more glyphosate adsorbed. The presence of phosphate significantly decreased the adsorption of glyphosate to the soils by competing with glyphosate for adsorption sites of soils. Meanwhile, the effects of phosphate on adsorption of glyphosate on the two variable charge soils were more significant than that on the permanent charge soil. When phosphate and glyphosate were added in the soils in different orders, the adsorption quantities of glyphosate on the soils were different, which followed GPS-soil>GPS-P-soil=GPS-soil-P>P-soil-GPS, meaning a complex interaction occurred among glyphosate, phosphate and the soils.展开更多
We describe a new species of gerreid fish,Gerres septemfasciatus,based on four specimens collected from the northern South China Sea.G.septemfasciatus most closely resembles G.limbatus in general appearance.However,G....We describe a new species of gerreid fish,Gerres septemfasciatus,based on four specimens collected from the northern South China Sea.G.septemfasciatus most closely resembles G.limbatus in general appearance.However,G.septemfasciatus is distinguished from the latter and other congeners by having 3 to 3.5 scales between the base of the fifth dorsal spine and lateral line.This species has a distinctive color pattern,including 7-8 regular,vertical,blue-grayish bands on its side.The distribution of this species is currently known to include the Chinese coastal waters of the South China Sea,but may be also include the coastal waters of southeastern Asia.展开更多
The clotting protein(CP) plays important and diverse roles in crustaceans,such as coagulation and lipid transportation.A clotting protein was purified from the hemolymph of Chinese shrimp Fenneropenaeus chinensis(name...The clotting protein(CP) plays important and diverse roles in crustaceans,such as coagulation and lipid transportation.A clotting protein was purified from the hemolymph of Chinese shrimp Fenneropenaeus chinensis(named as Fc-CP) with Q sepharose HP anion-exchange chromatography and phenyl sepharose HP hydrophobic interaction chromatography.Fc-CP was able to form stable clots in vitro in the presence of hemocyte lysate and Ca2+,suggesting that the clotting reaction is catalyzed by a Ca2+-dependent transglutaminase in shrimp hemocytes.The molecular mass of Fc-CP was 380 kDa under non-reducing conditions and 190 kDa under reducing conditions as was determined with SDS-PAGE.CP exists as disulfide-linked homodimers and oligomers.The N-terminal amino acid sequence of Fc-CP was identical to that of shrimps including Penaeus monodon,Farfantepenaeus paulensis and Litopenaeus vannamei;and similar to that of other decapods.The purified Fc-CP was digested with trypsin and verified on an ABI 4700 matrix-assisted laser desorption/ionization tandem time-of-flight(MALDI-TOF/TOF) mass spectrometry.Our results will aid to better understanding the coagulation mechanism of shrimp hemolymph.展开更多
Population genetic structure and historical demography of Chinese horseshoe crab(T.tridentatus) along southeast coast of China were inferred from the sequence data of mitochondrial cytochrome c oxidase subunit I(COI) ...Population genetic structure and historical demography of Chinese horseshoe crab(T.tridentatus) along southeast coast of China were inferred from the sequence data of mitochondrial cytochrome c oxidase subunit I(COI) fragment.The sequence analysis for 964 bp COI fragment was conducted in 28 individuals collected from five localities:Ninghai in Zhejiang Province,Meizhou and Zhangpu in Fujian Province,Beihai of Guangxi Zhuang Autonomous Region and Danzhou of Hainan Province.Sequence variation was relatively low with a total of seven transitions observed.In all localities,Haplotype H3 was the dominant type observed among eight haplotypes defined previously,and was at the center of radiation in Median-Joining network.The prolonged star-like network suggests a signature of population expansions.The level of diversity was low in total,with haplotype diversity(H d) being equal to 0.765 and nucleotide diversity(π) being equal to 0.001 18,respectively.The genetic structure analysis revealed the significant genetic difference between Ninghai and Danzhou populations.Both mismatch distribution analysis and Fu's F s test provided consistent inference of historic population expansion.The low genetic diversity of horseshoe crab observed along China coast indicated that urgent measures should be taken to protect this rare marine animal.展开更多
In 2003, the International Solanaceae Project (SOL) was initiated by an international consortium of ten countries including Korea, China, the United Kingdom, India, the Netherlands, France, Japan, Spain, Italy and the...In 2003, the International Solanaceae Project (SOL) was initiated by an international consortium of ten countries including Korea, China, the United Kingdom, India, the Netherlands, France, Japan, Spain, Italy and the United States. The first major effort of the SOL aimed to produce a DNA sequence map for euchromatin regions of 12 chromosomes of tomato (Solanum lycopersicum) before 2010. Here we present an update on Chinese effort for sequencing the euchromatin region of chromosome 3.展开更多
Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total s...Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total suspended solids,Chlorophyll a and Secchi transparency in the water column was found,while levels of water depth,electrical conductivity,total dissolved solids and NO 3--N concentration increased markedly post-dredging.The effects of dredging on dissolved oxygen,pH value and temperature were almost negligible.The zooplankton community structure responded rapidly to the environmental changes caused mainly by dredging.As a result,the abundance of rotifers decreased,while the density of zooplanktonic crustaceans increased markedly.The representative taxa were Brachionus angularis,B.budapestinensis,B.diversicornis,Synchaeta spp.and Neodiaptomus schmackeri.A distinct relationship between zooplankton taxa composition and their environment,unraveled by a redundancy analysis,indicating that the measured environment contributed to the variations in the zooplankton community structure to some extent.The first four synthetic environmental variables explained 51.7% of the taxonomic structure.Therefore,with the reduction of internal nutrient load and a shift in dominance by less eutrophic species,it inferred that dredging might be one of effective measures for environmental improvements of such lakes.展开更多
A GIS-based method was used to assess land suitability in the Qinling Mountains, Shaanxi Province of China through simultaneous consideration of physical features and current land use. Through interpretation of Landsa...A GIS-based method was used to assess land suitability in the Qinling Mountains, Shaanxi Province of China through simultaneous consideration of physical features and current land use. Through interpretation of Landsat TM images and extensive field visits the area was modeled into 40 land types in five altitudinal zones (valleys and gullies, hillsides and terraces, foothills, mid-mountain, and sub-alpine mountain). Then, a suitability score was assigned to five physical factors (climate, hydrology, topography, soil, and vegetation). Next, their integrated overall suitability value scores were compared with the observed land cover to determine whether it should be reallocated a new use. Results showed that the five suitability classes of agriculture, forest, grassland, farmland-woodland, and scrub-pasture had altitudinal stratification and a total of 1151 km2 (8.89%) of lands on the northern slopes of the Qinling Mountains had to be reallocated. To achieve this reallocation, 657 km2 of arable land should be reduced, and forest, grassland and scrub-pasture increased by 615 km2, 131 km2 and 405 km2, respectively. Implementation of these recommended land reallocations should help achieve suitable use of land resources and prevent land degradation.展开更多
Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2008. Debris flow mitigation and risk assessment is a key issue for reconstruc...Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2008. Debris flow mitigation and risk assessment is a key issue for reconstruction.The existing methods of inundation simulation are based on historical disasters and have no power of prediction.The rain-flood method can not yield detailed flow hydrograph and does not meet the need of inundation simulation. In this paper,the process of water flow was studied by using the Arc-SCS model combined with hydraulic method,and then the debris flow runoff process was calculated using the empirical formula combining the result from Arc-SCS.The peak discharge and runoff duration served as input of inundation simulation. Then,the dangerous area is predicted using kinematic wave method and Manning equation.Taking the debris flow in Huashiban gully in Beichuan County,Sichuan Province,China on 24 Sep.2008 as example,the peak discharge of water flow and debris flow were calculated as 35.52 m3·s-1 and 215.66 m3·s-,with error of 4.15%compared to the measured values.The simulated area of debris-flow deposition was 161,500 m2,vs.the measured area of 144,097 m2,in error of 81.75%.The simulated maximum depth was 12.3 m,consistent with the real maximum depth between 10 and 15 m according to the field survey.The minor error is mainly due to the flow impact on buildings and variations in cross-section configuration.The present methodology can be applied to predict debris flow magnitude and evaluate its risk in other watersheds inthe earthquake area.展开更多
In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass...In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.展开更多
Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous,and lower in High Field Strength Elements (HFSE).These rocks are higher in Large ...Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous,and lower in High Field Strength Elements (HFSE).These rocks are higher in Large Ion Lithophile Elements (LILE),thorium and uranium contents,positive lead anomalies,negative Nb-Ta anomalies,and enrichment in Light Rare Earth Elements (LREE).Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB),and rhyolites from the northern Okinawa Trough have the highest 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios.The NECS shelf margin basalts have lower 87 Sr/ 86 Sr ratios,ε N d and σ 18 O than the northern Okinawa Trough silicic rocks.According to 40 K– 40 Ar isotopic ages of basalts from the NECS shelf margin,rifting of the Okinawa Trough may have been active since at least 3.65–3.86 Ma.The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere.The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough,and the formation of basaltic magmas closely relates to the thinning of continental crust.The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough,which could have been generated by the interaction of basaltic melt with an enriched crustal component.From the Ryukyu island arc to East China,the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE),suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate,and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.展开更多
A field survey concerning lead and cadmium pollution in environment mediums and hair samples around the Chatian mercury mining deposit in western Hunan Province,China,was conducted to preliminarily evaluate their heal...A field survey concerning lead and cadmium pollution in environment mediums and hair samples around the Chatian mercury mining deposit in western Hunan Province,China,was conducted to preliminarily evaluate their health hazard to local inhabitants.The results show that mining wastes,especially tailing,contain high cadmium level with the maximum of 79.92μg/g. High levels of lead and cadmium are accumulated in surface water and paddy soil,respectively,and both metals pollution occurs in brown rice.The average daily intake dose(ADD)of lead for local adults via three routes reaches up to 7.7μg/(kg·d),exceeding the provision tolerable daily intake by JECFA of 3.5μg/(kg·d),and drinking water exposure route contributes the highest daily intake.As an indicator for heavy metal exposure,the hair of local population contains Pb(5.06±3.02)μg/g.The average daily intake dose of cadmium for adults is 0.119μg/(kg·d).More attention must be paid on health risk from lead pollution compared with cadmium.展开更多
In order to evaluate ecological risk of agrochemicals in agricultural environment,single and joint toxic effects of an importantherbicide and a typical heavy metal on root elongation of crops were investigated.Seeds o...In order to evaluate ecological risk of agrochemicals in agricultural environment,single and joint toxic effects of an importantherbicide and a typical heavy metal on root elongation of crops were investigated.Seeds of the three crops including wheat(Triticumaestivum),Chinese cabbage(Brassica pekimensis)and soybean(Glycine max)as the main crops in northeast China were exposed toacetochlor as a herbicide and lead(Pb)as a heavy metal using the pot-culture method,and meadow brown soil as one of the main soilsdistributed in northeast China was applied in the investigation.The results indicated that the interactive effects of the two pollutantson root elongation of the three crops were very complicated although they had markedly significant(P<0.01)linear interrelationshipsbased on the regression analyses.When the concentration of added Pb2+reached 200 mg/kg,acetochlor and Pb had an antagonisticeffect on the inhibition of root elongation of the three crops.However,acetochlor and Pb had significantly(P<0.05)synergic effects onthe inhibition of root elongation when concentration of added Pb2+was up to 1000 mg/kg.At the low concentration of added Pb,jointtoxicity of acetochlor and Pb was more dependent on the concentration of Pb.Among the three crops,wheat was the most sensitive tothe toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.展开更多
An experiments were carried out with treatments differing in nitrogen supply (0, 5 and 15 g N/m2) and CO2 levels (350 and 700 μmol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrost...An experiments were carried out with treatments differing in nitrogen supply (0, 5 and 15 g N/m2) and CO2 levels (350 and 700 μmol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply (15 g N/m2). Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon (10.6%) > dissolved organic carbon (7.5%) > labile oxidable carbon (6.6%) > carbohydrate carbon (4.1%). Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.展开更多
To investigate the relationships between the degradation of plant community and groundwater level in the lower reaches of the Tarim River, nine monitored sections were set along the main stream, where there had been n...To investigate the relationships between the degradation of plant community and groundwater level in the lower reaches of the Tarim River, nine monitored sections were set along the main stream, where there had been no runoff for nearly 30 years. The characteristics of plant communities were analyzed. It was found that the coverage of trees gradually decreased along the groundwater depth gradient, while the coverage of shrubs slightly increased rather than decreased at first and then gradually decreased, and the coverage of herbs steadily decreased at the beginning and then quickly decreased. The species diversity and species richness of both herbs and woody plants showed obvious degrading trends, while the variations in species evenness were slight. The degrading sequences of species were related to their physiological and ecological characteristics, especially their sensitivity to changes of groundwater table. The herbs with shallow roots first degenerated or disappeared when the groundwater table fell, and then did the deep-rooted herbs, and finally the trees and shrubs with strong tolerance to drought degenerated. The Populus euphratica communities showed typical degrading characteristics, namely the dominant species Populus euphratica remained its dominant status during the degradation. Overall, the existence of strongly tolerant-drought species was the obvious indication of plant species degradation; while simplification of community structure and the decrease of species richness were the obvious indication of plant community degradation.展开更多
The effects of H3PO4 and Ca(H2PO4)2 on compressive strength, water resistance, hydration process of thermally decomposed magnesium oxychloride cement(TDMOC) pastes were studied. The mineral composition, hydration prod...The effects of H3PO4 and Ca(H2PO4)2 on compressive strength, water resistance, hydration process of thermally decomposed magnesium oxychloride cement(TDMOC) pastes were studied. The mineral composition, hydration products and hydration heat release were analyzed by XRD, FT-IR, SEM and TAM air isothermal calorimeter, etc. After being modified by H3 PO4 and Ca(H2 PO4)2, the properties of the TDMOC are improved obviously. The compressive strength increases from 14.8 MPa to 48.1 MPa and 37.1 MPa, respectively. The strength retention coefficient(Kn) increases from 0.38 to 0.99 and 0.94, respectively. The 24 h hydration heat release decreases by 10% and 4% and the time of hydration peak appearing is delayed from 1 h to about 10 h. The XRD, FT-IR and SEM results show that the main composition is 5Mg(OH)2 ·MgCl2 ·8H2 O in the modified TDMOC pastes. The possible mechanism for the strength enhancement was discussed. The purposes are to extend the potential applications of the salt lake magnesium resources and to improve the mechanical properties of TDMOC.展开更多
基金The Basic Research and Development Programof China(No.2002CB410808) andthe Director Foundation of Institute of Soil Science ,Chinese Academyof Sciences
文摘Glyphosate (GPS) is a non-selective, post-mergence herbicide that is widely used throughout the world. Due to the similar molecular structures of glyphosate and phosphate, adsorption of glyphosate on soil is easily affected by coexisting phosphate, especially when phosphate is applied at a significant rate in farmland. This paper studied the effects of phosphate on the adsorption of glyphosate on three different types of Chinese soils including two variable charge soils and one permanent charge soil. The results indicated that Freundlich equations used to simulate glyphosate adsorption isotherms gave high correlation coefficients(0.990—0.998) with K values of 2751, 2451 and 166 for the zhuanhong soil(ZH soil, Laterite), red soil(RS, Udic Ferrisol) and Wushan paddy soil(WS soil, Anthrosol), respectively. The more the soil iron and aluminum oxides and clay contained, the more glyphosate adsorbed. The presence of phosphate significantly decreased the adsorption of glyphosate to the soils by competing with glyphosate for adsorption sites of soils. Meanwhile, the effects of phosphate on adsorption of glyphosate on the two variable charge soils were more significant than that on the permanent charge soil. When phosphate and glyphosate were added in the soils in different orders, the adsorption quantities of glyphosate on the soils were different, which followed GPS-soil>GPS-P-soil=GPS-soil-P>P-soil-GPS, meaning a complex interaction occurred among glyphosate, phosphate and the soils.
基金Supported by the Ministry of Science and Technology of the People's Republic of China under contract (No 2006FY110500)
文摘We describe a new species of gerreid fish,Gerres septemfasciatus,based on four specimens collected from the northern South China Sea.G.septemfasciatus most closely resembles G.limbatus in general appearance.However,G.septemfasciatus is distinguished from the latter and other congeners by having 3 to 3.5 scales between the base of the fifth dorsal spine and lateral line.This species has a distinctive color pattern,including 7-8 regular,vertical,blue-grayish bands on its side.The distribution of this species is currently known to include the Chinese coastal waters of the South China Sea,but may be also include the coastal waters of southeastern Asia.
基金supported by the National Natural Science Foundation of China(No.30600458)
文摘The clotting protein(CP) plays important and diverse roles in crustaceans,such as coagulation and lipid transportation.A clotting protein was purified from the hemolymph of Chinese shrimp Fenneropenaeus chinensis(named as Fc-CP) with Q sepharose HP anion-exchange chromatography and phenyl sepharose HP hydrophobic interaction chromatography.Fc-CP was able to form stable clots in vitro in the presence of hemocyte lysate and Ca2+,suggesting that the clotting reaction is catalyzed by a Ca2+-dependent transglutaminase in shrimp hemocytes.The molecular mass of Fc-CP was 380 kDa under non-reducing conditions and 190 kDa under reducing conditions as was determined with SDS-PAGE.CP exists as disulfide-linked homodimers and oligomers.The N-terminal amino acid sequence of Fc-CP was identical to that of shrimps including Penaeus monodon,Farfantepenaeus paulensis and Litopenaeus vannamei;and similar to that of other decapods.The purified Fc-CP was digested with trypsin and verified on an ABI 4700 matrix-assisted laser desorption/ionization tandem time-of-flight(MALDI-TOF/TOF) mass spectrometry.Our results will aid to better understanding the coagulation mechanism of shrimp hemolymph.
基金F5 Subject from Science and Technology Department of Fujian Province under contract No. 2008F5038the Open Foundation from Ocean Fishery Science and Technology in the Most Important Subjects of Zhejiang under contract No.20100210
文摘Population genetic structure and historical demography of Chinese horseshoe crab(T.tridentatus) along southeast coast of China were inferred from the sequence data of mitochondrial cytochrome c oxidase subunit I(COI) fragment.The sequence analysis for 964 bp COI fragment was conducted in 28 individuals collected from five localities:Ninghai in Zhejiang Province,Meizhou and Zhangpu in Fujian Province,Beihai of Guangxi Zhuang Autonomous Region and Danzhou of Hainan Province.Sequence variation was relatively low with a total of seven transitions observed.In all localities,Haplotype H3 was the dominant type observed among eight haplotypes defined previously,and was at the center of radiation in Median-Joining network.The prolonged star-like network suggests a signature of population expansions.The level of diversity was low in total,with haplotype diversity(H d) being equal to 0.765 and nucleotide diversity(π) being equal to 0.001 18,respectively.The genetic structure analysis revealed the significant genetic difference between Ninghai and Danzhou populations.Both mismatch distribution analysis and Fu's F s test provided consistent inference of historic population expansion.The low genetic diversity of horseshoe crab observed along China coast indicated that urgent measures should be taken to protect this rare marine animal.
文摘In 2003, the International Solanaceae Project (SOL) was initiated by an international consortium of ten countries including Korea, China, the United Kingdom, India, the Netherlands, France, Japan, Spain, Italy and the United States. The first major effort of the SOL aimed to produce a DNA sequence map for euchromatin regions of 12 chromosomes of tomato (Solanum lycopersicum) before 2010. Here we present an update on Chinese effort for sequencing the euchromatin region of chromosome 3.
基金supported by the High-Tech Research Program (863) of China (No.2009ZX07106-002-004)the National Natural Science Foundation of China (No.30870221,20877093,50808172, 50909091)
文摘Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total suspended solids,Chlorophyll a and Secchi transparency in the water column was found,while levels of water depth,electrical conductivity,total dissolved solids and NO 3--N concentration increased markedly post-dredging.The effects of dredging on dissolved oxygen,pH value and temperature were almost negligible.The zooplankton community structure responded rapidly to the environmental changes caused mainly by dredging.As a result,the abundance of rotifers decreased,while the density of zooplanktonic crustaceans increased markedly.The representative taxa were Brachionus angularis,B.budapestinensis,B.diversicornis,Synchaeta spp.and Neodiaptomus schmackeri.A distinct relationship between zooplankton taxa composition and their environment,unraveled by a redundancy analysis,indicating that the measured environment contributed to the variations in the zooplankton community structure to some extent.The first four synthetic environmental variables explained 51.7% of the taxonomic structure.Therefore,with the reduction of internal nutrient load and a shift in dominance by less eutrophic species,it inferred that dredging might be one of effective measures for environmental improvements of such lakes.
基金supported by the National"973 Project"(No.2009CB421003)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No:KZCX2-YW-1 36-2,KZCX2-YW- 111-03)the Foundation of State Key Lab.Of Ore Deposit Geochemistry
文摘Muchang 合成侵入被定位 Fengwei 镇和 Baoshan-Zhenkang 块的南方的大约 14 km 东南。裂缝相关的侵入在东方和西方由早阶段的 riebeckite nordmarkite 组成方面和不连续的边缘的地区，主导的 riebeckite 花岗石的迟了阶段的主要身体，和次要的 aegirine 花岗石。petrological 地球化学和在花岗石和联系 skarn 类型 Luziyuan Pb-Zn 存款之间的 Muchang 碱花岗石和关系的迟了阶段的 riebeckite 花岗石，起源和进化标明日期的 LA-ICP-MS 锆石 U-Pb 上的研究在这份报纸被讨论。结果证明 Muchang 碱花岗石属于 A 类型花岗石，它被丰富在 Al2O3， SiO2，全部的碱和 Fe 描绘，在有高 FeOT/MgO 比率的 MgO 和 CaO 内容的弄空。REE 集中相对高，高度展出 fractionated LREE 模式与显著地 Eu 否定异例。Muchang 花岗石显然在亲石元素元素被充实(例如， Rb， K， U 和 Th ) 并且高领域力量元素(例如， Zr， Hf， Nb， Y 和 Ga ) 与高度
基金Project supported by the National Basic Research Program of China (No. 2006CB400505)the National Natural Science Foundation of China (No. 40171007).
文摘A GIS-based method was used to assess land suitability in the Qinling Mountains, Shaanxi Province of China through simultaneous consideration of physical features and current land use. Through interpretation of Landsat TM images and extensive field visits the area was modeled into 40 land types in five altitudinal zones (valleys and gullies, hillsides and terraces, foothills, mid-mountain, and sub-alpine mountain). Then, a suitability score was assigned to five physical factors (climate, hydrology, topography, soil, and vegetation). Next, their integrated overall suitability value scores were compared with the observed land cover to determine whether it should be reallocated a new use. Results showed that the five suitability classes of agriculture, forest, grassland, farmland-woodland, and scrub-pasture had altitudinal stratification and a total of 1151 km2 (8.89%) of lands on the northern slopes of the Qinling Mountains had to be reallocated. To achieve this reallocation, 657 km2 of arable land should be reduced, and forest, grassland and scrub-pasture increased by 615 km2, 131 km2 and 405 km2, respectively. Implementation of these recommended land reallocations should help achieve suitable use of land resources and prevent land degradation.
基金supported by the National Basic Research Program of China(973 Program)(Grant No.2011CB409902)the National Natural Sciences Foundation of China(Grant No. 40671025)
文摘Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2008. Debris flow mitigation and risk assessment is a key issue for reconstruction.The existing methods of inundation simulation are based on historical disasters and have no power of prediction.The rain-flood method can not yield detailed flow hydrograph and does not meet the need of inundation simulation. In this paper,the process of water flow was studied by using the Arc-SCS model combined with hydraulic method,and then the debris flow runoff process was calculated using the empirical formula combining the result from Arc-SCS.The peak discharge and runoff duration served as input of inundation simulation. Then,the dangerous area is predicted using kinematic wave method and Manning equation.Taking the debris flow in Huashiban gully in Beichuan County,Sichuan Province,China on 24 Sep.2008 as example,the peak discharge of water flow and debris flow were calculated as 35.52 m3·s-1 and 215.66 m3·s-,with error of 4.15%compared to the measured values.The simulated area of debris-flow deposition was 161,500 m2,vs.the measured area of 144,097 m2,in error of 81.75%.The simulated maximum depth was 12.3 m,consistent with the real maximum depth between 10 and 15 m according to the field survey.The minor error is mainly due to the flow impact on buildings and variations in cross-section configuration.The present methodology can be applied to predict debris flow magnitude and evaluate its risk in other watersheds inthe earthquake area.
基金This work was financially supported by Project of Scientific Innova-tion, Chinese Academy of Sciences (ZKCX2-211).
文摘In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.
基金The Pilot Project of Knowledge Innovation Project,Chinese Academy of Sciences under contract Nos KZCX2- YW-211 and KZCX3-SW-223the National Natural Science Foundation of China under contract Nos 40830849 and 40976027+1 种基金Shandong Province Natural Science Foundation of China for Distinguished Young Scholars under contract No.JQ200913the National Major Fundamental Research and Development Project under contract No.G2000046701
文摘Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous,and lower in High Field Strength Elements (HFSE).These rocks are higher in Large Ion Lithophile Elements (LILE),thorium and uranium contents,positive lead anomalies,negative Nb-Ta anomalies,and enrichment in Light Rare Earth Elements (LREE).Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB),and rhyolites from the northern Okinawa Trough have the highest 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios.The NECS shelf margin basalts have lower 87 Sr/ 86 Sr ratios,ε N d and σ 18 O than the northern Okinawa Trough silicic rocks.According to 40 K– 40 Ar isotopic ages of basalts from the NECS shelf margin,rifting of the Okinawa Trough may have been active since at least 3.65–3.86 Ma.The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere.The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough,and the formation of basaltic magmas closely relates to the thinning of continental crust.The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough,which could have been generated by the interaction of basaltic melt with an enriched crustal component.From the Ryukyu island arc to East China,the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE),suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate,and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.
基金Project(40571008)supported by the National Natural Science Foundation of ChinaProject(KZCX3-SW-437)supported by Knowledge Innovation Programs of the Chinese Academy of Sciences
文摘A field survey concerning lead and cadmium pollution in environment mediums and hair samples around the Chatian mercury mining deposit in western Hunan Province,China,was conducted to preliminarily evaluate their health hazard to local inhabitants.The results show that mining wastes,especially tailing,contain high cadmium level with the maximum of 79.92μg/g. High levels of lead and cadmium are accumulated in surface water and paddy soil,respectively,and both metals pollution occurs in brown rice.The average daily intake dose(ADD)of lead for local adults via three routes reaches up to 7.7μg/(kg·d),exceeding the provision tolerable daily intake by JECFA of 3.5μg/(kg·d),and drinking water exposure route contributes the highest daily intake.As an indicator for heavy metal exposure,the hair of local population contains Pb(5.06±3.02)μg/g.The average daily intake dose of cadmium for adults is 0.119μg/(kg·d).More attention must be paid on health risk from lead pollution compared with cadmium.
基金Project supported by the National Science Fund for Distinguished Young Scholar of China(No.20225722)the National Natural Science Founda-tion of China(No.20337010)the National Basic Research Program (973)of China(No.2004CB418503).
文摘In order to evaluate ecological risk of agrochemicals in agricultural environment,single and joint toxic effects of an importantherbicide and a typical heavy metal on root elongation of crops were investigated.Seeds of the three crops including wheat(Triticumaestivum),Chinese cabbage(Brassica pekimensis)and soybean(Glycine max)as the main crops in northeast China were exposed toacetochlor as a herbicide and lead(Pb)as a heavy metal using the pot-culture method,and meadow brown soil as one of the main soilsdistributed in northeast China was applied in the investigation.The results indicated that the interactive effects of the two pollutantson root elongation of the three crops were very complicated although they had markedly significant(P<0.01)linear interrelationshipsbased on the regression analyses.When the concentration of added Pb2+reached 200 mg/kg,acetochlor and Pb had an antagonisticeffect on the inhibition of root elongation of the three crops.However,acetochlor and Pb had significantly(P<0.05)synergic effects onthe inhibition of root elongation when concentration of added Pb2+was up to 1000 mg/kg.At the low concentration of added Pb,jointtoxicity of acetochlor and Pb was more dependent on the concentration of Pb.Among the three crops,wheat was the most sensitive tothe toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.
基金supported by the Chinese Academy of Sciences (No KZCX2-YW-309)the National Basic Research Program (973) of China (No 2004CB418507)
文摘An experiments were carried out with treatments differing in nitrogen supply (0, 5 and 15 g N/m2) and CO2 levels (350 and 700 μmol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply (15 g N/m2). Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon (10.6%) > dissolved organic carbon (7.5%) > labile oxidable carbon (6.6%) > carbohydrate carbon (4.1%). Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.
基金The National Basic Research Programof China(No.2004CB720201) ,the Knowledge Innovation Project of Chinese Academyof Sciences(No.KZCX1-08-03) andthe National Natural Science Foundation of China(No.90102007)
文摘To investigate the relationships between the degradation of plant community and groundwater level in the lower reaches of the Tarim River, nine monitored sections were set along the main stream, where there had been no runoff for nearly 30 years. The characteristics of plant communities were analyzed. It was found that the coverage of trees gradually decreased along the groundwater depth gradient, while the coverage of shrubs slightly increased rather than decreased at first and then gradually decreased, and the coverage of herbs steadily decreased at the beginning and then quickly decreased. The species diversity and species richness of both herbs and woody plants showed obvious degrading trends, while the variations in species evenness were slight. The degrading sequences of species were related to their physiological and ecological characteristics, especially their sensitivity to changes of groundwater table. The herbs with shallow roots first degenerated or disappeared when the groundwater table fell, and then did the deep-rooted herbs, and finally the trees and shrubs with strong tolerance to drought degenerated. The Populus euphratica communities showed typical degrading characteristics, namely the dominant species Populus euphratica remained its dominant status during the degradation. Overall, the existence of strongly tolerant-drought species was the obvious indication of plant species degradation; while simplification of community structure and the decrease of species richness were the obvious indication of plant community degradation.
基金Project(B0210)supported by One Hundred Talent Project of Chinese Academy of SciencesProject(2008-G-158)supported by Science and Technology Tackling Key Program of Qinghai Province,China
文摘The effects of H3PO4 and Ca(H2PO4)2 on compressive strength, water resistance, hydration process of thermally decomposed magnesium oxychloride cement(TDMOC) pastes were studied. The mineral composition, hydration products and hydration heat release were analyzed by XRD, FT-IR, SEM and TAM air isothermal calorimeter, etc. After being modified by H3 PO4 and Ca(H2 PO4)2, the properties of the TDMOC are improved obviously. The compressive strength increases from 14.8 MPa to 48.1 MPa and 37.1 MPa, respectively. The strength retention coefficient(Kn) increases from 0.38 to 0.99 and 0.94, respectively. The 24 h hydration heat release decreases by 10% and 4% and the time of hydration peak appearing is delayed from 1 h to about 10 h. The XRD, FT-IR and SEM results show that the main composition is 5Mg(OH)2 ·MgCl2 ·8H2 O in the modified TDMOC pastes. The possible mechanism for the strength enhancement was discussed. The purposes are to extend the potential applications of the salt lake magnesium resources and to improve the mechanical properties of TDMOC.
