The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of ...The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of China.However,there is controversy about the specific location of this geographical boundary in academic community due to the complexity,transition and heterogeneity of the transitional zone,as well as the differences in the delimitation indicators and research purposes.To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China,combined with SRTM topographic data,temperature and precipitation data,Pinus massoniana forest and Pinus tabulaeformis forest,which represent subtropical coniferous forest in South China and temperate coniferous forest in North China respectively,were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation,the coldest month(January) average temperature,the warmest month(July) average temperature and the annual average temperature.The results show that:(1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indexes for the delimitation of subtropical and warm temperate zones.The boundary between the subtropical coniferous forest(Pinus massoniana forest) and temperate coniferous forest(Pinus tabulaeformis forest) is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin(the south slope of Qinling Mountains) at an altitude of 1000–1200 m,where the climatic indictors are stable:the annual precipitation is about 750–1000 mm,the annual average temperature is about 12–14℃,the coldest monthly average temperature is 0–4℃,and the warmest monthly average temperature is about 22–26℃.(2) It can be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators.Additionally,the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests,broad-leaved forests and shrubs between subtropical and warm temperate zones.The results provide a scientific basis for the selection of delimitation index of subtropical and warm temperate zones.展开更多
Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the recipr...Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the reciprocal effects of C:N:P stoichiometry in plant–litter–soil systems. The present study analyzed C:N:P ratios in four age groups of Chinese pine, Pinus tabulaeformis Carr., forests in Shanxi Province, China: plantation young forests(AY,<20 year-old); plantation middle-aged forests(AM, 21–30 year-old); natural young forests(NY,<30 year-old); and natural middle-aged forests(NM,31–50 year-old). The average C:N:P ratios calculated for tree, shrub, and herbaceous leaves, litter, and soil(0–100 cm) were generally higher in NY followed by NM,AM, and AY. C:N and C:P ratios were higher in litter than in leaves and soils, and reached higher values in the litter and leaves of young forests than in middle-aged forests;however, C:N and C:P ratios were higher in soils of middle-aged forests than in young forests. N:P ratios were higher in leaves than in litter and soils regardless of stand age; the consistent N:P<14 values found in all forests indicated N limitations. With plant leaves, C:P ratios were highest in trees, followed by herbs and shrubs, indicating a higher efficiency in tree leaf formation. C:N ratios decreased with increasing soil depth, whereas there was no trend for C:P and N:P ratios. C:N:P stoichiometry of forest foliage did not exhibit a consistent variation according to stand age. Research on the relationships between N:P, and P, N nutrient limits and the characteristics of vegetation nutrient adaptation need to be continued.展开更多
Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the est...Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the estimation of the global CH_(4) budget. In this study, surface water CH_(4) concentrations were measured and diffusive CH_(4) fluxes were estimated via a thin boundary layer model in a temperate river–reservoir system in North China, using spatial(33 sites) and temporal(four seasons) monitoring;the system has experienced intensive aquaculture disturbance. Our results indicated that the dissolved CH_(4) concentration in the reservoir ranged from 0.07 to 0.58 μmol/L, with an annual average of 0.13 ± 0.10 μmol/L, and the diffusive CH_(4) flux across the water–air interface ranged from 0.66 to 3.61 μmol/(m^(2)·hr),with an annual average of 1.67 ± 0.75 μmol/(m^(2)·hr). During the study period, the dissolved CH_(4) concentration was supersaturated and was a net source of atmospheric CH_(4) . Notably,CH_(4) concentration and diffusive flux portrayed large temporal and spatial heterogeneity.The river inflow zone was determined to be a hotspot for CH_(4) emissions, and its flux was significantly higher than that of the tributary and main basin;the CH_(4) flux in autumn was greater than that in other seasons. We also deduced that the CH_(4) concentration/diffusive flux was co-regulated mainly by water temperature, water depth, and water productivity(Chla, trophic status). Our results highlight the importance of considering the spatiotemporal variability of diffusive CH_(4) flux from temperate reservoirs to estimate the CH_(4) budget at regional and global scales.展开更多
The Qinling Mountains has always been regarded as an essential dividing line between the warm temperate zone and the subtropical zone in eastern China and plays a vital role in the geoecological pattern of China.Howev...The Qinling Mountains has always been regarded as an essential dividing line between the warm temperate zone and the subtropical zone in eastern China and plays a vital role in the geoecological pattern of China.However,there is controversy about the specific location of this geographical boundary in the academic community.As a product of the combined effects of zonal and non-zonal factors,the mountain altitudinal belts(MABs)can reflect both the horizontal zonality and the vertical zonality of vegetation distribution.Using the MAB information,we can not only profoundly understand the complex mountain system of QinlingDaba Mountains but can also judge its nature as a geographical boundary more scientifically.Therefore,based on the comparative analysis of basal belt,dominant belt characteristics and belt structure characteristics of the MABs in Qinling-Daba Mountains,subtropical and temperate mountains,this paper analyzed the MAB differences and similarities among Qinling-Daba Mountains,subtropical and temperate typical mountains,to reveal the vegetation distribution characteristics in the north-south transitional zone.The results show that:(1)The MABs of the southern part of QinlingDaba Mountains(southern slope of the Daba Mountains)are the same or similar to those of the Subtropical Mountains,and the MABs of the northern part of Qinling-Daba Mountains(northern slope of the Qinling Mountains)are similar to those of the temperate mountains.While it shows obvious transitional characteristics in the vast area between the northern slope of the Daba Mountains and the southern slope of the Qinling Mountains:the basal belts gradually transit from the evergreen broadleaved forest belt(basal belt in subtropical mountains)to the evergreen and deciduous broad-leaved mixed forest belt,and the dominant belts also transit from the evergreen broad-leaved forest belt to the evergreen and deciduous broad-leaved mixed forest belt or the deciduous broad-leaved forest belt.(2)The transitional zone between the subtropical zone and the warm temperate zone is located between the northern slope of the Daba Mountains and the southern slope of the Qinling Mountains.The southern boundary of the transitional zone is along the northern slope of Shennongjia Mountain-the northern slope of Micang Mountain-Baishuijiang Nature Reserve,and the northern boundary is along the southern slope of Funiu Mountain-the southern slope of Taibai Mountain-Lianhua Mountain.Additionally,in the transitional zone,the average temperature in January is between-5°C and 1°C,the annual average temperature is between 10°C and 13°C except Hanzhong Basin and Hanshui Valley,and the accumulated temperature above 10°C ranges from 2000°C to 4000°C,the annual rainfall is about 800-1000 mm.The results provide a scientific basis for revealing the characteristics of China’s north-south transitional zone and scientific division of the boundary between the subtropical zone and warm temperate zone in China.展开更多
Studies of seven typical soil profiles showed that in the argillic soils derived from loess in the warmtemperate zone of China all the oxides of Fe, Mn, Al and Si were enriched with the accumulation of clayfraction in...Studies of seven typical soil profiles showed that in the argillic soils derived from loess in the warmtemperate zone of China all the oxides of Fe, Mn, Al and Si were enriched with the accumulation of clayfraction in the profiles. But owing to the influence of oxidation-reduction process the migration velocity ofFe and Mn was faster than that of clay. The free degrees of those metals were in the sequence Mn>Fe>Al,which reflected their different chemical activities in soil. In soils at the same level of development, the freedegree of iron and its activity, the free degree of Al, Alo/Alt× 100, SiO_2/R_2O_3, Sio/Sit× 100, and themagnetic susceptibility were relatively close to each other respectively. It might be considered that both thefres degrees of Fe and Al and Alo/Alt× 100 could serve as the distinctive indexes for argillic soils in warmtemperate zone. The paleoclimate corresponding to the fifth layer of paleosol (s_5) in Lnochuan, Shaanxiwas warmer and more humid than the present, and the paleoecological landscape approximated to today'sbioclimatic belt between the temperate deciduous broadleaved forest and the semiarid forest types.The Mossbouer spectra of the colloidal fraction (<1um) in the clayified horizon of argillic dark loessialsoil, cinnamon soil, brown earth and (s_5) paleosol indicated the superparamagnetic state at room temperature.The magnetic splitting six line spectra were observed clearly at 80 K. The results fitted with a computershowed that hematite and goethite were predominant in iron oxides and commonly existed as fine particles.The proportion of hematite and goethite in soil colloids varied considerably with different climates. Thehigher the temperature, the larger the proportion of hematite.展开更多
The outdoor thermal environment might become worse than at present. It causes health injuries through the deterioration of the outdoor thermal condition. It is necessary to study how humans stay outdoors and adjust to...The outdoor thermal environment might become worse than at present. It causes health injuries through the deterioration of the outdoor thermal condition. It is necessary to study how humans stay outdoors and adjust to thermal conditions. The purpose of this study was to clarify the influence of the outdoor tropical urban thermal environment on a subject who has been acclimatized to the environment studied using the outdoor thermal environment evaluation index ETFe. In addition, the tendency of human impacts was clarified through comparison to subjects from a temperate thermal environment region. As a result, it was found that an ETFe of up to 35°C could be recognized as a temperate thermal environment. However, when the ETFe was greater than 40°C, the subject could not tolerate the environment. There was not a significant difference of psychological reaction between Thai people, who were acclimatized to the tropical climate, and Japanese people, who were acclimatized to the temperate climate.展开更多
The aim of this study was to study the distribution of Selenium （Se） and Mercury （Hg） in feed and drinking water in Heilongjiang Province and the effect on body of beef cattle. The experiment selected four areas o...The aim of this study was to study the distribution of Selenium （Se） and Mercury （Hg） in feed and drinking water in Heilongjiang Province and the effect on body of beef cattle. The experiment selected four areas of Qiqihar, Harbin, Jixi and Hegang Cities in Heilongjiang Province. In each area, a pasture was selected. Five beef cattle from each ranch were collected. At the same time, blood, liver, muscle, kidney, urine and faece of the cattle were collected, as well as drinking water, feed and formula feed from the ranch. The contents of Se and Hg in the collected samples were detected by inductively coupled plasma mass spectrometry. The results showed that the contents of Se in liver, kidney, urine and blood of beef cattle were increased with the increase of Se contents in drinking water, while the contents of Se in muscle tissue and manure were decreased. When the contents of Se in feed increased, the contents of them in muscle, manure and liver of beef cattle were increased frst and then decreased, while the contents of Se in kidney, urine and blood were decreased frst and then increased. When Hg contents in drinking water were increased, the contents of them in beef cattle tissue, blood and manure were increased frst and then decreased, and the contents of Se in urine were increased frst and them decreased. And when Hg contents in feed increased, the contents of Se and Me were also increased. In conclusion, Se and Hg contents in these areas were within the safety standards, meanwhile, the contents of Se and Hg in body tissues of beef cattle were affected to varying degrees by the contents of selenium and mercury in feed.展开更多
基金National Natural Science Foundation of China,No.41871350Scientific and Technological Basic Resources Survey Project,No.2017FY100900。
文摘The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of China.However,there is controversy about the specific location of this geographical boundary in academic community due to the complexity,transition and heterogeneity of the transitional zone,as well as the differences in the delimitation indicators and research purposes.To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China,combined with SRTM topographic data,temperature and precipitation data,Pinus massoniana forest and Pinus tabulaeformis forest,which represent subtropical coniferous forest in South China and temperate coniferous forest in North China respectively,were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation,the coldest month(January) average temperature,the warmest month(July) average temperature and the annual average temperature.The results show that:(1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indexes for the delimitation of subtropical and warm temperate zones.The boundary between the subtropical coniferous forest(Pinus massoniana forest) and temperate coniferous forest(Pinus tabulaeformis forest) is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin(the south slope of Qinling Mountains) at an altitude of 1000–1200 m,where the climatic indictors are stable:the annual precipitation is about 750–1000 mm,the annual average temperature is about 12–14℃,the coldest monthly average temperature is 0–4℃,and the warmest monthly average temperature is about 22–26℃.(2) It can be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators.Additionally,the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests,broad-leaved forests and shrubs between subtropical and warm temperate zones.The results provide a scientific basis for the selection of delimitation index of subtropical and warm temperate zones.
基金supported by the ‘‘Doctoral Scientific Research Foundation’’ of Heilongjiang Bayi Agricultural University,Grant No.XDB2015-02 and the ‘‘Strategic Priority Research Program’’ of the Chinese Academy of Sciences,Grant No.XDA05050203-04-01
文摘Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the reciprocal effects of C:N:P stoichiometry in plant–litter–soil systems. The present study analyzed C:N:P ratios in four age groups of Chinese pine, Pinus tabulaeformis Carr., forests in Shanxi Province, China: plantation young forests(AY,<20 year-old); plantation middle-aged forests(AM, 21–30 year-old); natural young forests(NY,<30 year-old); and natural middle-aged forests(NM,31–50 year-old). The average C:N:P ratios calculated for tree, shrub, and herbaceous leaves, litter, and soil(0–100 cm) were generally higher in NY followed by NM,AM, and AY. C:N and C:P ratios were higher in litter than in leaves and soils, and reached higher values in the litter and leaves of young forests than in middle-aged forests;however, C:N and C:P ratios were higher in soils of middle-aged forests than in young forests. N:P ratios were higher in leaves than in litter and soils regardless of stand age; the consistent N:P<14 values found in all forests indicated N limitations. With plant leaves, C:P ratios were highest in trees, followed by herbs and shrubs, indicating a higher efficiency in tree leaf formation. C:N ratios decreased with increasing soil depth, whereas there was no trend for C:P and N:P ratios. C:N:P stoichiometry of forest foliage did not exhibit a consistent variation according to stand age. Research on the relationships between N:P, and P, N nutrient limits and the characteristics of vegetation nutrient adaptation need to be continued.
基金supported by the National Nature Science Foundation of China(Nos.41771516,41771122)the Bureau of Luanhe Diversion Project of the Haihe River Water Conservancy Commission,Ministry of Water Resources of China and Tianjin Water Affairs Bureau project(Nos.HYGP-2019-C-130,TJGC-2019-C-060)。
文摘Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the estimation of the global CH_(4) budget. In this study, surface water CH_(4) concentrations were measured and diffusive CH_(4) fluxes were estimated via a thin boundary layer model in a temperate river–reservoir system in North China, using spatial(33 sites) and temporal(four seasons) monitoring;the system has experienced intensive aquaculture disturbance. Our results indicated that the dissolved CH_(4) concentration in the reservoir ranged from 0.07 to 0.58 μmol/L, with an annual average of 0.13 ± 0.10 μmol/L, and the diffusive CH_(4) flux across the water–air interface ranged from 0.66 to 3.61 μmol/(m^(2)·hr),with an annual average of 1.67 ± 0.75 μmol/(m^(2)·hr). During the study period, the dissolved CH_(4) concentration was supersaturated and was a net source of atmospheric CH_(4) . Notably,CH_(4) concentration and diffusive flux portrayed large temporal and spatial heterogeneity.The river inflow zone was determined to be a hotspot for CH_(4) emissions, and its flux was significantly higher than that of the tributary and main basin;the CH_(4) flux in autumn was greater than that in other seasons. We also deduced that the CH_(4) concentration/diffusive flux was co-regulated mainly by water temperature, water depth, and water productivity(Chla, trophic status). Our results highlight the importance of considering the spatiotemporal variability of diffusive CH_(4) flux from temperate reservoirs to estimate the CH_(4) budget at regional and global scales.
基金funded by the Natural Science Foundation of China(Grant No.41871350)Scientific and Technological Basic Resources Survey Project(Grant No.2017FY100900)。
文摘The Qinling Mountains has always been regarded as an essential dividing line between the warm temperate zone and the subtropical zone in eastern China and plays a vital role in the geoecological pattern of China.However,there is controversy about the specific location of this geographical boundary in the academic community.As a product of the combined effects of zonal and non-zonal factors,the mountain altitudinal belts(MABs)can reflect both the horizontal zonality and the vertical zonality of vegetation distribution.Using the MAB information,we can not only profoundly understand the complex mountain system of QinlingDaba Mountains but can also judge its nature as a geographical boundary more scientifically.Therefore,based on the comparative analysis of basal belt,dominant belt characteristics and belt structure characteristics of the MABs in Qinling-Daba Mountains,subtropical and temperate mountains,this paper analyzed the MAB differences and similarities among Qinling-Daba Mountains,subtropical and temperate typical mountains,to reveal the vegetation distribution characteristics in the north-south transitional zone.The results show that:(1)The MABs of the southern part of QinlingDaba Mountains(southern slope of the Daba Mountains)are the same or similar to those of the Subtropical Mountains,and the MABs of the northern part of Qinling-Daba Mountains(northern slope of the Qinling Mountains)are similar to those of the temperate mountains.While it shows obvious transitional characteristics in the vast area between the northern slope of the Daba Mountains and the southern slope of the Qinling Mountains:the basal belts gradually transit from the evergreen broadleaved forest belt(basal belt in subtropical mountains)to the evergreen and deciduous broad-leaved mixed forest belt,and the dominant belts also transit from the evergreen broad-leaved forest belt to the evergreen and deciduous broad-leaved mixed forest belt or the deciduous broad-leaved forest belt.(2)The transitional zone between the subtropical zone and the warm temperate zone is located between the northern slope of the Daba Mountains and the southern slope of the Qinling Mountains.The southern boundary of the transitional zone is along the northern slope of Shennongjia Mountain-the northern slope of Micang Mountain-Baishuijiang Nature Reserve,and the northern boundary is along the southern slope of Funiu Mountain-the southern slope of Taibai Mountain-Lianhua Mountain.Additionally,in the transitional zone,the average temperature in January is between-5°C and 1°C,the annual average temperature is between 10°C and 13°C except Hanzhong Basin and Hanshui Valley,and the accumulated temperature above 10°C ranges from 2000°C to 4000°C,the annual rainfall is about 800-1000 mm.The results provide a scientific basis for revealing the characteristics of China’s north-south transitional zone and scientific division of the boundary between the subtropical zone and warm temperate zone in China.
文摘Studies of seven typical soil profiles showed that in the argillic soils derived from loess in the warmtemperate zone of China all the oxides of Fe, Mn, Al and Si were enriched with the accumulation of clayfraction in the profiles. But owing to the influence of oxidation-reduction process the migration velocity ofFe and Mn was faster than that of clay. The free degrees of those metals were in the sequence Mn>Fe>Al,which reflected their different chemical activities in soil. In soils at the same level of development, the freedegree of iron and its activity, the free degree of Al, Alo/Alt× 100, SiO_2/R_2O_3, Sio/Sit× 100, and themagnetic susceptibility were relatively close to each other respectively. It might be considered that both thefres degrees of Fe and Al and Alo/Alt× 100 could serve as the distinctive indexes for argillic soils in warmtemperate zone. The paleoclimate corresponding to the fifth layer of paleosol (s_5) in Lnochuan, Shaanxiwas warmer and more humid than the present, and the paleoecological landscape approximated to today'sbioclimatic belt between the temperate deciduous broadleaved forest and the semiarid forest types.The Mossbouer spectra of the colloidal fraction (<1um) in the clayified horizon of argillic dark loessialsoil, cinnamon soil, brown earth and (s_5) paleosol indicated the superparamagnetic state at room temperature.The magnetic splitting six line spectra were observed clearly at 80 K. The results fitted with a computershowed that hematite and goethite were predominant in iron oxides and commonly existed as fine particles.The proportion of hematite and goethite in soil colloids varied considerably with different climates. Thehigher the temperature, the larger the proportion of hematite.
文摘The outdoor thermal environment might become worse than at present. It causes health injuries through the deterioration of the outdoor thermal condition. It is necessary to study how humans stay outdoors and adjust to thermal conditions. The purpose of this study was to clarify the influence of the outdoor tropical urban thermal environment on a subject who has been acclimatized to the environment studied using the outdoor thermal environment evaluation index ETFe. In addition, the tendency of human impacts was clarified through comparison to subjects from a temperate thermal environment region. As a result, it was found that an ETFe of up to 35°C could be recognized as a temperate thermal environment. However, when the ETFe was greater than 40°C, the subject could not tolerate the environment. There was not a significant difference of psychological reaction between Thai people, who were acclimatized to the tropical climate, and Japanese people, who were acclimatized to the temperate climate.
基金Supported by"Beef Cattle Safety Production Technology Innovation Integration and Demonstration"(2014BAD13B03-1)from the National Science and Technology Support Program"Beef Safety Production Technology Integration and Demonstration"
文摘The aim of this study was to study the distribution of Selenium （Se） and Mercury （Hg） in feed and drinking water in Heilongjiang Province and the effect on body of beef cattle. The experiment selected four areas of Qiqihar, Harbin, Jixi and Hegang Cities in Heilongjiang Province. In each area, a pasture was selected. Five beef cattle from each ranch were collected. At the same time, blood, liver, muscle, kidney, urine and faece of the cattle were collected, as well as drinking water, feed and formula feed from the ranch. The contents of Se and Hg in the collected samples were detected by inductively coupled plasma mass spectrometry. The results showed that the contents of Se in liver, kidney, urine and blood of beef cattle were increased with the increase of Se contents in drinking water, while the contents of Se in muscle tissue and manure were decreased. When the contents of Se in feed increased, the contents of them in muscle, manure and liver of beef cattle were increased frst and then decreased, while the contents of Se in kidney, urine and blood were decreased frst and then increased. When Hg contents in drinking water were increased, the contents of them in beef cattle tissue, blood and manure were increased frst and then decreased, and the contents of Se in urine were increased frst and them decreased. And when Hg contents in feed increased, the contents of Se and Me were also increased. In conclusion, Se and Hg contents in these areas were within the safety standards, meanwhile, the contents of Se and Hg in body tissues of beef cattle were affected to varying degrees by the contents of selenium and mercury in feed.
